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Ranta I, Wright P, Suilamo S, Kemppainen R, Schubert G, Kapanen M, Keyriläinen J. Clinical feasibility of a commercially available MRI-only method for radiotherapy treatment planning of the brain. J Appl Clin Med Phys 2023; 24:e14044. [PMID: 37345212 PMCID: PMC10476982 DOI: 10.1002/acm2.14044] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 01/19/2023] [Accepted: 04/25/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND Advancements in deep-learning based synthetic computed tomography (sCT) image conversion methods have enabled the development of magnetic resonance imaging (MRI)-only based radiotherapy treatment planning (RTP) of the brain. PURPOSE This study evaluates the clinical feasibility of a commercial, deep-learning based MRI-only RTP method with respect to dose calculation and patient positioning verification performance in RTP of the brain. METHODS Clinical validation of dose calculation accuracy was performed by a retrospective evaluation for 25 glioma and 25 brain metastasis patients. Dosimetric and image quality of the studied MRI-only RTP method was evaluated by a direct comparison of the sCT-based and computed tomography (CT)-based external beam radiation therapy (EBRT) images and treatment plans. Patient positioning verification accuracy of sCT images was evaluated retrospectively for 10 glioma and 10 brain metastasis patients based on clinical cone-beam computed tomography (CBCT) imaging. RESULTS An average mean dose difference of Dmean = 0.1% for planning target volume (PTV) and 0.6% for normal tissue (NT) structures were obtained for glioma patients. Respective results for brain metastasis patients were Dmean = 0.5% for PTVs and Dmean =1.0% for NTs. Global three-dimensional (3D) gamma pass rates using 2%/2 mm dose difference and distance-to-agreement (DTA) criterion were 98.0% for the glioma subgroup, and 95.2% for the brain metastasis subgroup using 1%/1 mm criterion. Mean distance differences of <1.0 mm were observed in all Cartesian directions between CT-based and sCT-based CBCT patient positioning in both subgroups. CONCLUSIONS In terms of dose calculation and patient positioning accuracy, the studied MRI-only method demonstrated its clinical feasibility for RTP of the brain. The results encourage the use of the studied method as part of a routine clinical workflow.
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Affiliation(s)
- Iiro Ranta
- Department of Physics and AstronomyUniversity of TurkuTurkuFinland
- Department of Medical PhysicsTurku University HospitalTurkuFinland
- Department of Oncology and RadiotherapyTurku University HospitalTurkuFinland
| | - Pauliina Wright
- Department of Medical PhysicsTurku University HospitalTurkuFinland
- Department of Oncology and RadiotherapyTurku University HospitalTurkuFinland
| | - Sami Suilamo
- Department of Medical PhysicsTurku University HospitalTurkuFinland
- Department of Oncology and RadiotherapyTurku University HospitalTurkuFinland
| | - Reko Kemppainen
- HUS Diagnostic CenterUniversity of Helsinki and Helsinki University HospitalHelsinkiFinland
| | | | - Mika Kapanen
- Department of Medical PhysicsMedical Imaging CenterTampere University HospitalTampereFinland
- Department of OncologyUnit of RadiotherapyTampere University HospitalTampereFinland
| | - Jani Keyriläinen
- Department of Physics and AstronomyUniversity of TurkuTurkuFinland
- Department of Medical PhysicsTurku University HospitalTurkuFinland
- Department of Oncology and RadiotherapyTurku University HospitalTurkuFinland
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Saikkonen A, Ojala J, Sipilä P, Boman E, Keyriläinen J. Validation of HDR brachytherapy doses in the treatment of keloid scars using the egs_brachy Monte Carlo application. Phys Med Biol 2023; 68. [PMID: 36893475 DOI: 10.1088/1361-6560/acc30a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 03/09/2023] [Indexed: 03/11/2023]
Abstract
OBJECTIVE Radiotherapy is a well-known alternative in the treatment of keloid scars to reduce the recurrence of scars. The purpose of this study was to investigate the feasibility and accuracy of dose delivered from a high-dose-rate (HDR) afterloaders in keloid scar brachytherapy using Monte Carlo (MC) simulations and measurements. APPROACH Treatment doses and central axis (CAX) dose profiles were measured using radiophotoluminescence dosimeters and radiochromic films, respectively, with two HDR afterloaders, both using an Ir-192 source, in a phantom made of solid water and polycarbonate sheets. The nominal treatment dose calculated by the AAPM Task Group No. 43 (TG-43) dose model was set to 8.5 Gy at a distance of 0.5 cm laterally from the middle of the source line located in a plastic applicator simulating a 15 cm long surgically removed scar treatment with 30 equally spaced (0.5 cm) source positions. The dose profiles were measured at three different distances from the applicator and the absolute doses at four points at different distances. MC simulations were performed using the egs_brachy, which is based on EGSnrc code system. MAIN RESULTS The measured and simulated dose profiles match well, especially at 10.0 mm (difference < 1 %) and 15.0 mm depths (difference < 4 %), and with a small dose difference at 5.0 mm depth (difference < 4 %). Point dose measurements agreed well in the dose maximum area (difference < 7 %) with the simulated dose profiles, although the largest difference near the edge of the profile was < 30 %. The dose differences between the TG-43 dose model and the MC simulation were small (differences < 4 %). SIGNIFICANCE Simulated and measured dose levels at a depth of 0.5 cm showed that the nominal treatment dose can be achieved with the utilized setup. The measurement results of the absolute dose agree well with the corresponding simulation results.
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Affiliation(s)
- Aleksi Saikkonen
- Department of Medical Physics & Department of Oncology and Radiotherapy, TYKS Turku University Hospital, Hämeentie 11, Turku, Varsinais-Suomi, 20521, FINLAND
| | - Jarkko Ojala
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, PO Box 2000, 33521 Tampere, Tampere, 33521, FINLAND
| | - Petri Sipilä
- Radiation and Nuclear Safety Authority, Jokiniemenkuja 1, Vantaa, Uusimaa, 01370, FINLAND
| | - Eeva Boman
- Department of Oncology, Tampere University Hospital, Teiskontie 35, PO BOX 2000, Tampere, FI-33521, FINLAND
| | - Jani Keyriläinen
- Department of Medical Physics & Department of Oncology and Radiotherapy, TYKS Turku University Hospital, Hämeentie 11, Turku, Varsinais-Suomi, 20521, FINLAND
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Partanen M, Niemelä J, Ojala J, Keyriläinen J, Kapanen M. Properties of IBA Razor Nano Chamber in small-field radiation therapy using 6 MV FF, 6 MV FFF, and 10 MV FFF photon beams. Acta Oncol 2021; 60:1419-1424. [PMID: 34596486 DOI: 10.1080/0284186x.2021.1979644] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Small megavoltage photon fields are increasingly used in modern radiotherapy techniques such as stereotactic radiotherapy. Therefore, it is important to study the reliability of dosimetry in the small-field conditions. The IBA Razor Nano Chamber (Nano chamber) ionization chamber is particularly intended for small-field measurements. In this work, properties of the Nano chamber were studied with both measurements and Monte Carlo (MC) simulations. MATERIAL AND METHODS The measurements and MC simulations were performed with 6 MV, 6 MV FFF and 10 MV FFF photon beams from the Varian TrueBeam linear accelerator. The source-to-surface distance was fixed at 100 cm. The measurements and MC simulations included profiles, percentage depth doses (PDD), and output factors (OF) in square jaw-collimated fields. The MC simulations were performed with the EGSnrc software system in a large water phantom. RESULTS The measured profiles and PDDs obtained with the Nano chamber were compared against IBA Razor Diode, PTW microDiamond and the PTW Semiflex ionization chamber. These results indicate that the Nano chamber is a high-resolution detector and thus suitable for small field profile measurements down to field sizes 2 × 2 cm2 and appropriate for the PDD measurements. The field output correction factors kQclin, Qmsrfclin, fmsr and field OFs ΩQclin, Qmsrfclin, fmsr were determined according to TRS-483 protocol In the 6 MV FF and FFF beams, the determined correction factors kQclin, Qmsrfclin, fmsr were within 1.2% for the field sizes of 1 × 1 cm2-3 × 3 cm2 and the experimental and MC defined field output factors ΩQclin,Qmsrfclin,fmsr showed good agreement. CONCLUSION The Nano chamber with its small cavity volume is a potential detector for the small-field dosimetry. In this study, the properties of this detector were characterized with measurements and MC simulations. The determined correction factors kQclin, Qmsrfclin, fmsr are novel results for the NC in the TrueBeam fields.
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Affiliation(s)
- Mari Partanen
- Unit of Radiotherapy, Department of Oncology, Tampere University Hospital, Tampere, Finland
- Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, Tampere, Finland
| | - Jarkko Niemelä
- Department of Medical Physics, Turku University Hospital, Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
- Department of Physics and Astronomy, University of Turku, Turku, Finland
| | - Jarkko Ojala
- Unit of Radiotherapy, Department of Oncology, Tampere University Hospital, Tampere, Finland
- Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, Tampere, Finland
| | - Jani Keyriläinen
- Department of Medical Physics, Turku University Hospital, Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | - Mika Kapanen
- Unit of Radiotherapy, Department of Oncology, Tampere University Hospital, Tampere, Finland
- Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, Tampere, Finland
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Keyriläinen J, Sjöblom O, Turnbull-Smith S, Hovirinta T, Minn H. Clinical experience and cost evaluation of magnetic resonance imaging -only workflow in radiation therapy planning of prostate cancer. Phys Imaging Radiat Oncol 2021; 19:66-71. [PMID: 34307921 PMCID: PMC8295845 DOI: 10.1016/j.phro.2021.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/31/2021] [Accepted: 07/01/2021] [Indexed: 12/24/2022]
Abstract
Using MRI-only for prostate cancer radiation therapy planning (RTP) can reduce costs. An MRI-only workflow is particularly suitable for medium-sized and large departments. Omitting CT in the RTP workflow saves scanner, staff, and patient time.
Background and purpose In radiation therapy (RT), significant improvements have been made recently particularly in the practices of planning imaging. This study aimed to conduct a cost evaluation between magnetic resonance imaging (MRI) -only and combined computed tomography (CT) and MRI workflows. Materials and methods The time-driven activity-based costing (TDABC) model was used to conduct a cost evaluation between the two workflows in those steps, where cost differences were expected. Costs were divided into capital costs and operational costs. The former consisted of fixed, one-time expenses, e.g. the purchase of a scanner, whereas the latter were partially based on the amount of activity consumed i.e. time required for image acquisition, image registration and structure contouring. Results In a review over a period of 10 years for 300 annual prostate cancer patients, the total cost of the workflow steps included in the study for an individual patient applying the MRI-only workflow was 903 € (100%), comprised of 537 € (59%) capital costs and 366 € (41%) operational costs. The corresponding total cost for an individual patient applying the CT + MRI workflow was 922 € (100%), comprised of 197 € (21%) capital costs and 726 € (79%) operational costs. In 10 years for 3000 patients, a total saving of 58,544 € (2%) was achieved with the MRI-only workflow compared with the dual imaging workflow. Conclusions MRI-only workflow is a feasible and economic way to perform clinical RT for localized prostate cancer, in particular for medium- and large-sized departments treating a sufficient number of patients.
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Affiliation(s)
- Jani Keyriläinen
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland
- Corresponding author at: Hämeentie 11, FIN-20521 Turku, Finland.
| | - Olli Sjöblom
- Turku University School of Economics, Information Systems Science, Rehtorinpellonkatu 3, FI-20500 Turku, Finland
| | - Sonja Turnbull-Smith
- Philips Oy, Philips Medical Systems MR Finland, Radiation Oncology Helsinki, Äyritie 4, FI-01510 Vantaa, Finland
| | - Taru Hovirinta
- Department of Finance, The Hospital District of Southwest Finland, Kiinamyllynkatu 4-8, FI-20521 Turku, Finland
| | - Heikki Minn
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland
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Niemelä J, Partanen M, Ojala J, Kapanen M, Keyriläinen J. Dose-area product ratio in external small-beam radiotherapy: beam shape, size and energy dependencies in clinical photon beams. Biomed Phys Eng Express 2021; 7. [PMID: 33836522 DOI: 10.1088/2057-1976/abf6aa] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 04/09/2021] [Indexed: 11/12/2022]
Abstract
In small-field radiotherapy (RT), a significant challenge is to define the amount of radiation dose absorbed in the patient where the quality of the beam has to be measured with high accuracy. The properties of a proposed new beam quality specifier, namely the dose-area-product ratio at 20 and 10 cm depths in water or DAPR20,10, were studied to yield more information on its feasibility over the conventional quality specifier tissue-phantom ratio or TPR20,10. The DAPR20,10may be measured with a large-area ionization chamber (LAC) instead of small volume chambers or semi-conductors where detector, beam and water phantom positioning and beam perturbations introduce uncertainties. The effects of beam shape, size and energy on the DAPR20,10were studied and it was shown that the DAPR20,10increases with increasing beam energy similarly to TPR20,10but in contrast exhibits a small beam size and shape dependence. The beam profile outside the beam limiting devices has been shown to have a large contribution to the DAPR20,10. There is potential in large area chambers to be used in DAPR measurement and its use in dosimetry of small-beam RT for beam quality measurements.
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Affiliation(s)
- Jarkko Niemelä
- University of Turku, Department of Physics and Astronomy, FI-20014 Turku, Finland.,Department of Medical Physics, Turku University Hospital, PO Box 52, FI-20521 Turku, Finland.,Department of Oncology and Radiotherapy, Turku University Hospital, PO Box 52, FI-20521 Turku, Finland
| | - Mari Partanen
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, PO Box 2000, FI-33521 Tampere, Finland.,Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, PO Box 2000, FI-33521 Tampere, Finland
| | - Jarkko Ojala
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, PO Box 2000, FI-33521 Tampere, Finland.,Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, PO Box 2000, FI-33521 Tampere, Finland
| | - Mika Kapanen
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, PO Box 2000, FI-33521 Tampere, Finland.,Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, PO Box 2000, FI-33521 Tampere, Finland
| | - Jani Keyriläinen
- Department of Medical Physics, Turku University Hospital, PO Box 52, FI-20521 Turku, Finland.,Department of Oncology and Radiotherapy, Turku University Hospital, PO Box 52, FI-20521 Turku, Finland
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Kiljunen T, Akram S, Niemelä J, Löyttyniemi E, Seppälä J, Heikkilä J, Vuolukka K, Kääriäinen OS, Heikkilä VP, Lehtiö K, Nikkinen J, Gershkevitsh E, Borkvel A, Adamson M, Zolotuhhin D, Kolk K, Pang EPP, Tuan JKL, Master Z, Chua MLK, Joensuu T, Kononen J, Myllykangas M, Riener M, Mokka M, Keyriläinen J. A Deep Learning-Based Automated CT Segmentation of Prostate Cancer Anatomy for Radiation Therapy Planning-A Retrospective Multicenter Study. Diagnostics (Basel) 2020; 10:E959. [PMID: 33212793 PMCID: PMC7697786 DOI: 10.3390/diagnostics10110959] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/06/2020] [Accepted: 11/13/2020] [Indexed: 12/24/2022] Open
Abstract
A commercial deep learning (DL)-based automated segmentation tool (AST) for computed tomography (CT) is evaluated for accuracy and efficiency gain within prostate cancer patients. Thirty patients from six clinics were reviewed with manual- (MC), automated- (AC) and automated and edited (AEC) contouring methods. In the AEC group, created contours (prostate, seminal vesicles, bladder, rectum, femoral heads and penile bulb) were edited, whereas the MC group included empty datasets for MC. In one clinic, lymph node CTV delineations were evaluated for interobserver variability. Compared to MC, the mean time saved using the AST was 12 min for the whole data set (46%) and 12 min for the lymph node CTV (60%), respectively. The delineation consistency between MC and AEC groups according to the Dice similarity coefficient (DSC) improved from 0.78 to 0.94 for the whole data set and from 0.76 to 0.91 for the lymph nodes. The mean DSCs between MC and AC for all six clinics were 0.82 for prostate, 0.72 for seminal vesicles, 0.93 for bladder, 0.84 for rectum, 0.69 for femoral heads and 0.51 for penile bulb. This study proves that using a general DL-based AST for CT images saves time and improves consistency.
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Affiliation(s)
- Timo Kiljunen
- Docrates Cancer Center, Saukonpaadenranta 2, FI-00180 Helsinki, Finland; (T.J.); (J.K.); (M.M.); (M.R.)
| | - Saad Akram
- MVision Ai, c/o Terkko Health hub, Haartmaninkatu 4, FI-00290 Helsinki, Finland; (S.A.); (J.N.)
| | - Jarkko Niemelä
- MVision Ai, c/o Terkko Health hub, Haartmaninkatu 4, FI-00290 Helsinki, Finland; (S.A.); (J.N.)
| | - Eliisa Löyttyniemi
- Department of Biostatistics, University of Turku, Kiinamyllynkatu 10, FI-20014 Turku, Finland;
| | - Jan Seppälä
- Kuopio University Hospital, Center of Oncology, Kelkkailijantie 7, FI-70210 Kuopio, Finland; (J.S.); (J.H.); (K.V.); (O.-S.K.)
| | - Janne Heikkilä
- Kuopio University Hospital, Center of Oncology, Kelkkailijantie 7, FI-70210 Kuopio, Finland; (J.S.); (J.H.); (K.V.); (O.-S.K.)
| | - Kristiina Vuolukka
- Kuopio University Hospital, Center of Oncology, Kelkkailijantie 7, FI-70210 Kuopio, Finland; (J.S.); (J.H.); (K.V.); (O.-S.K.)
| | - Okko-Sakari Kääriäinen
- Kuopio University Hospital, Center of Oncology, Kelkkailijantie 7, FI-70210 Kuopio, Finland; (J.S.); (J.H.); (K.V.); (O.-S.K.)
| | - Vesa-Pekka Heikkilä
- Oulu University Hospital, Department of Oncology and Radiotherapy, Kajaanintie 50, FI-90220 Oulu, Finland; (V.-P.H.); (K.L.); (J.N.)
- University of Oulu, Research Unit of Medical Imaging, Physics and Technology, Aapistie 5 A, FI-90220 Oulu, Finland
| | - Kaisa Lehtiö
- Oulu University Hospital, Department of Oncology and Radiotherapy, Kajaanintie 50, FI-90220 Oulu, Finland; (V.-P.H.); (K.L.); (J.N.)
| | - Juha Nikkinen
- Oulu University Hospital, Department of Oncology and Radiotherapy, Kajaanintie 50, FI-90220 Oulu, Finland; (V.-P.H.); (K.L.); (J.N.)
- University of Oulu, Research Unit of Medical Imaging, Physics and Technology, Aapistie 5 A, FI-90220 Oulu, Finland
| | - Eduard Gershkevitsh
- North Estonia Medical Centre, J. Sütiste tee 19, 13419 Tallinn, Estonia; (E.G.); (A.B.); (M.A.); (D.Z.); (K.K.)
| | - Anni Borkvel
- North Estonia Medical Centre, J. Sütiste tee 19, 13419 Tallinn, Estonia; (E.G.); (A.B.); (M.A.); (D.Z.); (K.K.)
| | - Merve Adamson
- North Estonia Medical Centre, J. Sütiste tee 19, 13419 Tallinn, Estonia; (E.G.); (A.B.); (M.A.); (D.Z.); (K.K.)
| | - Daniil Zolotuhhin
- North Estonia Medical Centre, J. Sütiste tee 19, 13419 Tallinn, Estonia; (E.G.); (A.B.); (M.A.); (D.Z.); (K.K.)
| | - Kati Kolk
- North Estonia Medical Centre, J. Sütiste tee 19, 13419 Tallinn, Estonia; (E.G.); (A.B.); (M.A.); (D.Z.); (K.K.)
| | - Eric Pei Ping Pang
- National Cancer Centre Singapore, Division of Radiation Oncology, 11 Hospital Crescent, Singapore 169610, Singapore; (E.P.P.P); (J.K.L.T); (Z.M.); (M.L.K.C)
| | - Jeffrey Kit Loong Tuan
- National Cancer Centre Singapore, Division of Radiation Oncology, 11 Hospital Crescent, Singapore 169610, Singapore; (E.P.P.P); (J.K.L.T); (Z.M.); (M.L.K.C)
- Oncology Academic Programme, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Zubin Master
- National Cancer Centre Singapore, Division of Radiation Oncology, 11 Hospital Crescent, Singapore 169610, Singapore; (E.P.P.P); (J.K.L.T); (Z.M.); (M.L.K.C)
| | - Melvin Lee Kiang Chua
- National Cancer Centre Singapore, Division of Radiation Oncology, 11 Hospital Crescent, Singapore 169610, Singapore; (E.P.P.P); (J.K.L.T); (Z.M.); (M.L.K.C)
- Oncology Academic Programme, Duke-NUS Medical School, Singapore 169857, Singapore
- National Cancer Centre Singapore, Division of Medical Sciences, Singapore 169610, Singapore
| | - Timo Joensuu
- Docrates Cancer Center, Saukonpaadenranta 2, FI-00180 Helsinki, Finland; (T.J.); (J.K.); (M.M.); (M.R.)
| | - Juha Kononen
- Docrates Cancer Center, Saukonpaadenranta 2, FI-00180 Helsinki, Finland; (T.J.); (J.K.); (M.M.); (M.R.)
| | - Mikko Myllykangas
- Docrates Cancer Center, Saukonpaadenranta 2, FI-00180 Helsinki, Finland; (T.J.); (J.K.); (M.M.); (M.R.)
| | - Maigo Riener
- Docrates Cancer Center, Saukonpaadenranta 2, FI-00180 Helsinki, Finland; (T.J.); (J.K.); (M.M.); (M.R.)
| | - Miia Mokka
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland; (M.M.); (J.K.)
| | - Jani Keyriläinen
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland; (M.M.); (J.K.)
- Turku University Hospital, Department of Medical Physics, Hämeentie 11, FI-20521 Turku, Finland
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Ranta I, Teuho J, Linden J, Klén R, Teräs M, Kapanen M, Keyriläinen J. Assessment of MRI-Based Attenuation Correction for MRI-Only Radiotherapy Treatment Planning of the Brain. Diagnostics (Basel) 2020; 10:E299. [PMID: 32422950 PMCID: PMC7278007 DOI: 10.3390/diagnostics10050299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 04/27/2020] [Accepted: 05/11/2020] [Indexed: 12/17/2022] Open
Abstract
Magnetic resonance imaging-only radiotherapy treatment planning (MRI-only RTP) and positron emission tomography (PET)-MRI imaging require generation of synthetic computed tomography (sCT) images from MRI images. In this study, initial dosimetric evaluation was performed for a previously developed MRI-based attenuation correction (MRAC) method for use in MRI-only RTP of the brain. MRAC-based sCT images were retrospectively generated from Dixon MR images of 20 patients who had previously received external beam radiation therapy (EBRT). Bone segmentation performance and Dice similarity coefficient of the sCT conversion method were evaluated for bone volumes on CT images. Dose calculation accuracy was assessed by recalculating the CT-based EBRT plans using the sCT images as the base attenuation data. Dose comparison was done for the sCT- and CT-based EBRT plans in planning target volume (PTV) and organs at risk (OAR). Parametric dose comparison showed mean relative differences of <0.4% for PTV and <1.0% for OARs. Mean gamma index pass rates of 95.7% with the 2%/2 mm agreement criterion and 96.5% with the 1%/1 mm agreement criterion were determined for glioma and metastasis patients, respectively. Based on the results, MRI-only RTP using sCT images generated from MRAC images can be a feasible alternative for radiotherapy of the brain.
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Affiliation(s)
- Iiro Ranta
- Department of Physics and Astronomy, University of Turku, Vesilinnantie 5, FI-20014 Turku, Finland;
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland; (J.T.); (M.T.)
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland
| | - Jarmo Teuho
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland; (J.T.); (M.T.)
- Turku PET Centre, University of Turku and Turku University Hospital, Kiinamyllynkatu 4-8, FI-20521 Turku, Finland; (J.L.); (R.K.)
| | - Jani Linden
- Turku PET Centre, University of Turku and Turku University Hospital, Kiinamyllynkatu 4-8, FI-20521 Turku, Finland; (J.L.); (R.K.)
- Department of Mathematics and Statistics, University of Turku, Vesilinnantie 5, FI-20014 Turku, Finland
| | - Riku Klén
- Turku PET Centre, University of Turku and Turku University Hospital, Kiinamyllynkatu 4-8, FI-20521 Turku, Finland; (J.L.); (R.K.)
| | - Mika Teräs
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland; (J.T.); (M.T.)
- Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FI-20014 Turku, Finland
| | - Mika Kapanen
- Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, Teiskontie 35, FI-33521 Tampere, Finland;
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, Teiskontie 35, FI-33521 Tampere, Finland
| | - Jani Keyriläinen
- Department of Physics and Astronomy, University of Turku, Vesilinnantie 5, FI-20014 Turku, Finland;
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland; (J.T.); (M.T.)
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland
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Kuisma A, Ranta I, Keyriläinen J, Suilamo S, Wright P, Pesola M, Warner L, Löyttyniemi E, Minn H. Validation of automated magnetic resonance image segmentation for radiation therapy planning in prostate cancer. Phys Imaging Radiat Oncol 2020; 13:14-20. [PMID: 33458302 PMCID: PMC7807774 DOI: 10.1016/j.phro.2020.02.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/23/2019] [Accepted: 02/24/2020] [Indexed: 01/06/2023]
Abstract
Background and purpose Magnetic resonance imaging (MRI) is increasingly used in radiation therapy planning of prostate cancer (PC) to reduce target volume delineation uncertainty. This study aimed to assess and validate the performance of a fully automated segmentation tool (AST) in MRI based radiation therapy planning of PC. Material and methods Pelvic structures of 65 PC patients delineated in an MRI-only workflow according to established guidelines were included in the analysis. Automatic vs manual segmentation by an experienced oncologist was compared with geometrical parameters, such as the dice similarity coefficient (DSC). Fifteen patients had a second MRI within 15 days to assess repeatability of the AST for prostate and seminal vesicles. Furthermore, we investigated whether hormonal therapy or body mass index (BMI) affected the AST results. Results The AST showed high agreement with manual segmentation expressed as DSC (mean, SD) for delineating prostate (0.84, 0.04), bladder (0.92, 0.04) and rectum (0.86, 0.04). For seminal vesicles (0.56, 0.17) and penile bulb (0.69, 0.12) the respective agreement was moderate. Performance of AST was not influenced by neoadjuvant hormonal therapy, although those on treatment had significantly smaller prostates than the hormone-naïve patients (p < 0.0001). In repeat assessment, consistency of prostate delineation resulted in mean DSC of 0.89, (SD 0.03) between the paired MRI scans for AST, while mean DSC of manual delineation was 0.82, (SD 0.05). Conclusion Fully automated MRI segmentation tool showed good agreement and repeatability compared with manual segmentation and was found clinically robust in patients with PC. However, manual review and adjustment of some structures in individual cases remain important in clinical use.
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Affiliation(s)
- Anna Kuisma
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland
| | - Iiro Ranta
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland.,Turku University Hospital, Department of Medical Physics, Hämeentie 11, FI-20521 Turku, Finland.,University of Turku, Department of Physics and Astronomy, Vesilinnantie 5, FI-20014 University of Turku, Finland
| | - Jani Keyriläinen
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland.,Turku University Hospital, Department of Medical Physics, Hämeentie 11, FI-20521 Turku, Finland.,University of Turku, Department of Physics and Astronomy, Vesilinnantie 5, FI-20014 University of Turku, Finland
| | - Sami Suilamo
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland.,Turku University Hospital, Department of Medical Physics, Hämeentie 11, FI-20521 Turku, Finland
| | - Pauliina Wright
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland.,Turku University Hospital, Department of Medical Physics, Hämeentie 11, FI-20521 Turku, Finland
| | - Marko Pesola
- Philips MR Therapy Oy, Äyritie 4, FI-01510 Vantaa, Finland
| | - Lizette Warner
- Philips MR Oncology, 3000 Minuteman Road, Andover, MA 01810, United States
| | - Eliisa Löyttyniemi
- University of Turku, Department of Biostatistics, Kiinamyllynkatu 10, FI-20014 University of Turku, Finland
| | - Heikki Minn
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland
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Depauw N, Keyriläinen J, Suilamo S, Warner L, Bzdusek K, Olsen C, Kooy H. MRI-based IMPT planning for prostate cancer. Radiother Oncol 2019; 144:79-85. [PMID: 31734604 DOI: 10.1016/j.radonc.2019.10.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 10/15/2019] [Accepted: 10/16/2019] [Indexed: 11/15/2022]
Abstract
PURPOSE Treatment planning for proton therapy requires the relative proton stopping power ratio (RSP) information of the patient for accurate dose calculations. RSP are conventionally obtained after mapping of the Hounsfield units (HU) from a calibrated patient computed tomography (CT). One or multiple CT are needed for a given treatment which represents additional, undesired dose to the patient. For prostate cancer, magnetic resonance imaging (MRI) scans are the gold standard for segmentation while offering dose-less imaging. We here quantify the clinical applicability of converted MR images as a substitute for intensity modulated proton therapy (IMPT) treatment of the prostate. METHODS MRCAT (Magnetic Resonance for Calculating ATtenuation) is a Philips-developed technology which produces a synthetic CT image consisting of five HU from a specific set of MRI acquisitions. MRCAT and original planning CT data sets were obtained for ten patients. An IMPT plan was generated on the MRCAT for each patient. Plans were produced such that they fulfill the prostate protocol in use at Massachusetts General Hospital (MGH). The plans were then recomputed onto the nominal planning CT for each patient. Robustness analyses (±5 mm setup shifts and ±3.5 % range uncertainties) were also performed. RESULTS Comparison of MRCAT plans and their recomputation onto the planning CT plan showed excellent agreement. Likewise, dose perturbations due to setup shifts and range uncertainties were well within clinical acceptance demonstrating the clinical viability of the approach. CONCLUSIONS This work demonstrate the clinical acceptability of substituting MR converted RSP images instead of CT for IMPT planning of prostate cancer. This further translates into higher contouring accuracy along with lesser imaging dose.
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Affiliation(s)
- Nicolas Depauw
- Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital (MGH), Boston, USA.
| | - Jani Keyriläinen
- Department of Medical Physics & Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | - Sami Suilamo
- Department of Medical Physics & Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | | | - Karl Bzdusek
- Philips Healthcare, Philips Radiation Oncology Systems, Fitchburg, USA
| | - Christine Olsen
- Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital (MGH), Boston, USA
| | - Hanne Kooy
- Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital (MGH), Boston, USA
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10
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Kemppainen R, Suilamo S, Ranta I, Pesola M, Halkola A, Eufemio A, Minn H, Keyriläinen J. Assessment of dosimetric and positioning accuracy of a magnetic resonance imaging-only solution for external beam radiotherapy of pelvic anatomy. Phys Imaging Radiat Oncol 2019; 11:1-8. [PMID: 33458269 PMCID: PMC7807675 DOI: 10.1016/j.phro.2019.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 05/30/2019] [Accepted: 06/02/2019] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND AND PURPOSE The clinical feasibility of synthetic computed tomography (sCT) images derived from magnetic resonance imaging (MRI) images for external beam radiation therapy (EBRT) planning have been studied and adopted into clinical use recently. This paper evaluates the dosimetric and positioning performance of a sCT approach for different pelvic cancers. MATERIALS AND METHODS Seventy-five patients receiving EBRT at Turku University Hospital (Turku, Finland) were enrolled in the study. The sCT images were generated as part of a clinical MRI-simulation procedure. Dose calculation accuracy was assessed by comparing the sCT-based calculation with a CT-based calculation. In addition, we evaluated the patient position verification accuracy for both digitally reconstructed radiograph (DRR) and cone beam computed tomography (CBCT) -based image guidance using a subset of the cohort. Furthermore, the relevance of using continuous Hounsfield unit values was assessed. RESULTS The mean (standard deviation) relative dose difference in the planning target volume mean dose computed over various cancer groups was less than 0.2 (0.4)% between sCT and CT. Among all groups, the average minimum gamma-index pass-rates were better than 95% with a 2%/2mm gamma-criteria. The difference between sCT- and CT-DRR-based patient positioning was less than 0.3 (1.4) mm in all directions. The registrations of sCT to CBCT produced similar results as compared with CT to CBCT registrations. CONCLUSIONS The use of sCT for clinical EBRT dose calculation and patient positioning in the investigated types of pelvic cancers was dosimetrically and geometrically accurate for clinical use.
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Affiliation(s)
- Reko Kemppainen
- Philips Oy, Äyritie 4, FI-01510 Vantaa, Finland
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2 C, FI-02150 Espoo, Finland
| | - Sami Suilamo
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
| | - Iiro Ranta
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
| | | | | | | | - Heikki Minn
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
| | - Jani Keyriläinen
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
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11
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Ranta I, Kemppainen R, Keyriläinen J, Suilamo S, Heikkinen S, Kapanen M, Saunavaara J. Quality assurance measurements of geometric accuracy for magnetic resonance imaging-based radiotherapy treatment planning. Phys Med 2019; 62:47-52. [PMID: 31153398 DOI: 10.1016/j.ejmp.2019.04.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/29/2019] [Accepted: 04/24/2019] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Using magnetic resonance imaging (MRI) as the only imaging method for radiotherapy treatment planning (RTP) is becoming more common as MRI-only RTP solutions have evolved. The geometric accuracy of MR images is an essential factor of image quality when determining the suitability of MRI for RTP. The need is therefore clear for clinically feasible quality assurance (QA) methods for the geometric accuracy measurement. MATERIALS AND METHODS This work evaluates long-term stability of geometric accuracy and the validity of a 2D geometric accuracy QA method compared to a prototype 3D method and analysis software in routine QA. The long-term follow-up measurements were conducted on one of the 1.5 T scanners over a period of 19 months using both methods. Inter-scanner variability of geometric distortions was also evaluated in three 1.5 T and three 3 T MRI scanners from a single vendor by using the prototype 3D QA method. RESULTS The geometric accuracy of the magnetic resonance for radiotherapy (MR-RT) platform remained stable within 2 mm at distances of <250 mm from isocenter. All scanners achieved good geometric accuracy with mean geometric distortions of <1 mm at <150 mm and <2 mm at <250 mm from the isocenter. Both measurement methods provided relevant information about geometric distortions. CONCLUSIONS Geometric distortions are often considered a limitation of MRI-only RTP. Results indicate that geometric accuracy of modern scanners remain within acceptable limits by default even after many years of clinical use based on the 3D QA evaluation.
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Affiliation(s)
- Iiro Ranta
- Department of Physics and Astronomy, University of Turku, Vesilinnantie 5, FI-20014 Turku, Finland; Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland; Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland.
| | | | - Jani Keyriläinen
- Department of Physics and Astronomy, University of Turku, Vesilinnantie 5, FI-20014 Turku, Finland; Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland; Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
| | - Sami Suilamo
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland; Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
| | - Samuli Heikkinen
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
| | - Mika Kapanen
- Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, P.O. Box 2000, FI-33521 Tampere, Finland; Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, P.O. Box 2000, FI-33521 Tampere, Finland
| | - Jani Saunavaara
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
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12
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Saikkonen A, Niemelä J, Sipilä P, Keyriläinen J. Commissioning of the MultiRad 350 cell and small animal x-ray irradiation system. Phys Med 2019; 59:107-111. [PMID: 30928058 DOI: 10.1016/j.ejmp.2019.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 01/22/2019] [Accepted: 03/05/2019] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The main objective of this study was to commission a commercial x-ray irradiation system to be used for cell and small animal studies. MATERIALS AND METHODS Evaluated characteristics of an x-ray irradiator included dose linearity and dose repeatability with respect to time, x-ray beam profiles, light field to irradiation field agreement and absolute radiation dose. Radiochromic films, ionization chambers and radiophotoluminescence dosimeters were used for dosimetry and the maximum settings of the irradiator were applied. RESULTS The dose was linear with time using several voltage settings and the dose repeatability with time was within 5% beyond 15 s of irradiation time. The x-ray beam profiles were acceptable, flatness being less than 4%. The light field to irradiation field agreement appeared to have a maximum difference of 0.5 cm; the irradiation field being closer to the irradiator's door than the light field. CONCLUSIONS The MultiRad 350 x-ray irradiation system can be used in a safe and controlled manner for irradiating cells and small animals. However, the user should be careful to verify the filter position prior the irradiation.
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Affiliation(s)
- Aleksi Saikkonen
- Department of Physics and Astronomy, Turku University, Vesilinnantie 5, FIN-20521 Turku, Finland; Department of Medical Physics & Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, FIN-20521 Turku, Finland.
| | - Jarkko Niemelä
- Department of Physics and Astronomy, Turku University, Vesilinnantie 5, FIN-20521 Turku, Finland; Department of Medical Physics & Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, FIN-20521 Turku, Finland
| | - Petri Sipilä
- Radiation and Nuclear Safety Authority (STUK), Laippatie 4, FIN-00880 Helsinki, Finland
| | - Jani Keyriläinen
- Department of Physics and Astronomy, Turku University, Vesilinnantie 5, FIN-20521 Turku, Finland; Department of Medical Physics & Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, FIN-20521 Turku, Finland
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Valve A, Keyriläinen J, Kulmala J. Compass model-based quality assurance for stereotactic VMAT treatment plans. Phys Med 2017; 44:42-50. [DOI: 10.1016/j.ejmp.2017.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 10/22/2017] [Accepted: 11/09/2017] [Indexed: 12/31/2022] Open
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Partanen M, Ojala J, Niemelä J, Björkqvist M, Keyriläinen J, Kapanen M. Comparison of two Monte Carlo-based codes for small-field dose calculations in external beam radiotherapy. Acta Oncol 2017; 56:891-893. [PMID: 28464738 DOI: 10.1080/0284186x.2017.1292048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Mari Partanen
- Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, Tampere, Finland
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, Tampere, Finland
| | - Jarkko Ojala
- Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, Tampere, Finland
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, Tampere, Finland
| | - Jarkko Niemelä
- Department of Medical Physics, Turku University Hospital, Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | - Mikko Björkqvist
- Department of Medical Physics, Turku University Hospital, Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | - Jani Keyriläinen
- Department of Medical Physics, Turku University Hospital, Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | - Mika Kapanen
- Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, Tampere, Finland
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, Tampere, Finland
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15
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Kemppainen R, Suilamo S, Tuokkola T, Lindholm P, Deppe MH, Keyriläinen J. Magnetic resonance-only simulation and dose calculation in external beam radiation therapy: a feasibility study for pelvic cancers. Acta Oncol 2017; 56:792-798. [PMID: 28270011 DOI: 10.1080/0284186x.2017.1293290] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND The clinical feasibility of using pseudo-computed tomography (pCT) images derived from magnetic resonance (MR) images for external bean radiation therapy (EBRT) planning for prostate cancer patients has been well demonstrated. This paper investigates the feasibility of applying an MR-derived, pCT planning approach to additional types of cancer in the pelvis. MATERIAL AND METHODS Fifteen patients (five prostate cancer patients, five rectal cancer patients, and five gynecological cancer patients) receiving EBRT at Turku University Hospital (Turku, Finland) were included in the study. Images from an MRCAT (Magnetic Resonance for Calculating ATtenuation, Philips, Vantaa, Finland) pCT method were generated as a part of a clinical MR-simulation procedure. Dose calculation accuracy was assessed by comparing the pCT-based calculation with a CT-based calculation. In addition, the degree of geometric accuracy was studied. RESULTS The median relative difference of PTV mean dose between CT and pCT images was within 0.8% for all tumor types. When assessing the tumor site-specific accuracy, the median [range] relative dose differences to the PTV mean were 0.7 [-0.11;1.05]% for the prostate cases, 0.3 [-0.25;0.57]% for the rectal cases, and 0.09 [-0.69;0.25]% for the gynecological cancer cases. System-induced geometric distortion was measured to be less than 1 mm for all PTV volumes and the effect on the PTV median dose was less than 0.1%. CONCLUSIONS According to the comparison, using pCT for clinical EBRT planning and dose calculation in the three investigated types of pelvic cancers is feasible. Further studies are required to demonstrate the applicability to a larger cohort of patients.
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Affiliation(s)
- Reko Kemppainen
- Philips MR Therapy, Vantaa, Finland
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Sami Suilamo
- Department of Medical Physics, Turku University Hospital, Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | - Terhi Tuokkola
- Turku PET-Centre, Turku University Hospital, Finland and University of Turku, Turku, Finland
| | - Paula Lindholm
- Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | | | - Jani Keyriläinen
- Department of Medical Physics, Turku University Hospital, Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
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Niemelä J, Partanen M, Ojala J, Sipilä P, Björkqvist M, Kapanen M, Keyriläinen J. Measurement and properties of the dose–area product ratio in external small-beam radiotherapy. Phys Med Biol 2017; 62:4870-4883. [DOI: 10.1088/1361-6560/aa6861] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Seppälä J, Suilamo S, Tenhunen M, Sailas L, Virsunen H, Kaleva E, Keyriläinen J. Dosimetric Comparison and Evaluation of 4 Stereotactic Body Radiotherapy Techniques for the Treatment of Prostate Cancer. Technol Cancer Res Treat 2016; 16:238-245. [PMID: 28279147 PMCID: PMC5616037 DOI: 10.1177/1533034616682156] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
PURPOSE The aim of this study was to compare dosimetric characteristics, monitor unit, and delivery efficiency of 4 different stereotactic body radiotherapy techniques for the treatment of prostate cancer. METHODS This study included 8 patients with localized prostate cancer. Dosimetric assets of 4 delivery techniques for stereotactic body radiotherapy were evaluated: robotic CyberKnife, noncoplanar intensity-modulated radiotherapy, and 2 intensity-modulated arc therapy techniques (RapidArc and Elekta volumetric-modulated arc therapy). All the plans had equal treatment margins and a prescription dose of 35 Gy in 5 fractions. RESULTS Statistically significant differences were observed in homogeneity index and mean doses of bladder wall and penile bulb, all of which were highest with CyberKnife. No significant differences were observed in the mean doses of rectum, with values of 15.2 ± 2.6, 13.3 ± 2.6, 13.1 ± 2.8, and 13.8 ± 1.6 Gy with CyberKnife, RapidArc, volumetric-modulated arc therapy, and noncoplanar intensity-modulated radiotherapy, respectively. The highest dose conformity was realized with RapidArc. The dose coverage of the planning target volume was lowest with noncoplanar intensity-modulated radiotherapy. Treatment times and number of monitor units were largest with CyberKnife (on average 34.0 ± 5.0 minutes and 8704 ± 1449 monitor units) and least with intensity-modulated arc therapy techniques (on average 5.1 ± 1.1 minutes and 2270 ± 497 monitor units). CONCLUSION Compared to CyberKnife, the RapidArc, volumetric-modulated arc therapy, and noncoplanar intensity-modulated radiotherapy produced treatment plans with similar dosimetric quality, with RapidArc achieving the highest dose conformity. Overall, the dosimetric differences between the studied techniques were marginal, and thus, the choice of the technique should rather focus on the delivery accuracies and dose delivery times.
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Affiliation(s)
- Jan Seppälä
- 1 Radiotherapy Department, Cancer Center, Kuopio University Hospital, Kuopio, Finland
| | - Sami Suilamo
- 2 Department of Medical Physics & Department of Radiotherapy and Oncology, Turku University Hospital, Turku, Finland
| | - Mikko Tenhunen
- 3 Comprehensive Cancer Center, Helsinki University Central Hospital, Helsinki, Finland
| | - Liisa Sailas
- 4 Department of Radiotherapy, North Karelia Central Hospital, Joensuu, Finland
| | - Heli Virsunen
- 1 Radiotherapy Department, Cancer Center, Kuopio University Hospital, Kuopio, Finland
| | - Erna Kaleva
- 3 Comprehensive Cancer Center, Helsinki University Central Hospital, Helsinki, Finland.,5 Lahti Department of Radiotherapy, Tampere University Hospital, Lahti, Finland
| | - Jani Keyriläinen
- 2 Department of Medical Physics & Department of Radiotherapy and Oncology, Turku University Hospital, Turku, Finland.,3 Comprehensive Cancer Center, Helsinki University Central Hospital, Helsinki, Finland
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Tuomikoski L, Kapanen M, Collan J, Keyriläinen J, Saarilahti K, Loimu V, Seppälä T, Tenhunen M. Toward a more patient-specific model of post-radiotherapy saliva secretion for head and neck cancer patients. Acta Oncol 2015. [PMID: 26203929 DOI: 10.3109/0284186x.2015.1067717] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Reduction of saliva secretion is a common side effect following radiotherapy (RT) for cancer of the head and neck region. The aim of this study is to predict the post-RT salivary function for individual patients prior to treatment and to recognise possible differences in individual radiosensitivity. MATERIAL AND METHODS A predictive model for post-RT salivary function was validated for 64 head and neck cancer patients. The input parameters for the model were salivary excretion fraction (sEF) measured by 99mTc-pertechnetate scintigraphy, total stimulated salivary flow and mean absorbed dose for the major salivary glands. SEF values after RT relative to the baseline before RT (rEF) were compared among the patients using the distance ΔrEF between single gland rEF and the corresponding expected value at the dose response curve. RESULTS A significant correlation (R = 0.86, p = 0.018) was found between the modelled and the measured values of stimulated salivary flow six months after RT. The average prediction error for the saliva flow rate was 6 ml/15 min. A linear relationship between ΔrEF for the left and the right parotid glands was observed both six (R = 0.53) and 12 (R = 0.79) months after RT. The average of absolute values of ΔrEF was 0.20 for parotid glands and 0.22 for submandibular glands. CONCLUSIONS The salivary flow model was validated for 64 patients. The results imply, that one explanation for the discrepancies between the predicted and the measured salivary flow rate values and the common variations found in ΔrEF for the parotid glands may be differences in patients' individual response to radiation. However, quantitative extraction of individual radiosensitivity would require further studies in order to take it into account in predictive models.
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Affiliation(s)
- Laura Tuomikoski
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Mika Kapanen
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
- b Department of Medical Physics , Tampere University Hospital , Tampere , Finland
| | - Juhani Collan
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Jani Keyriläinen
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
- c Department of Oncology and Radiotherapy , Turku University Hospital , Turku , Finland
| | - Kauko Saarilahti
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Venla Loimu
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Tiina Seppälä
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Mikko Tenhunen
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
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Korhonen J, Kapanen M, Sonke JJ, Wee L, Salli E, Keyriläinen J, Seppälä T, Tenhunen M. Feasibility of MRI-based reference images for image-guided radiotherapy of the pelvis with either cone-beam computed tomography or planar localization images. Acta Oncol 2015; 54:889-95. [PMID: 25233439 DOI: 10.3109/0284186x.2014.958197] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE This study introduces methods to conduct image-guided radiotherapy (IGRT) of the pelvis with either cone-beam computed tomography (CBCT) or planar localization images by relying solely on magnetic resonance imaging (MRI)-based reference images. MATERIAL AND METHODS Feasibility of MRI-based reference images for IGRT was evaluated against kV CBCT (50 scans, 5 prostate cancer patients) and kV & MV planar (5 & 5 image pairs and patients) localization images by comparing the achieved patient position corrections to those obtained by standard CT-based reference images. T1/T2*-weighted in-phase MRI, Hounsfield unit conversion-based heterogeneous pseudo-CT, and bulk pseudo-CT images were applied for reference against localization CBCTs, and patient position corrections were obtained by automatic image registration. IGRT with planar localization images was performed manually by 10 observers using reference digitally reconstructed radiographs (DRRs) reconstructed from the pseudo-CTs and standard CTs. Quality of pseudo-DRRs against CT-DRRs was evaluated with image similarity metrics. RESULTS The SDs of differences between CBCT-to-MRI and CBCT-to-CT automatic gray-value registrations were ≤1.0 mm & ≤0.8° and ≤2.5 mm & ≤3.6° with 10 cm diameter cubic VOI and prostate-shaped VOI, respectively. The corresponding values for reference heterogeneous pseudo-CT were ≤1.0 mm & ≤0.7° and ≤2.2 mm & ≤3.3°, respectively. Heterogeneous pseudo-CT was the only type of MRI-based reference image working reliably with automatic bone registration (SDs were ≤0.9 mm & ≤0.7°). The differences include possible residual errors from planning CT to MRI registration. The image similarity metrics were significantly (p≤0.01) better in agreement between heterogeneous pseudo-DRRs and CT-DRRs than between bulk pseudo-DRRs and CT-DRRs. The SDs of differences in manual registrations (3D) with planar kV and MV localization images were ≤1.0 mm and ≤1.7 mm, respectively, between heterogeneous pseudo-DRRs and CT-DRRs, and ≤1.4 mm and ≤2.1 mm between bulk pseudo-DRRs and CT-DRRs. CONCLUSION This study demonstrated that it is feasible to conduct IGRT of the pelvis with MRI-based reference images.
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Affiliation(s)
- Juha Korhonen
- Clinical Research Institute Helsinki University Central Hospital Ltd , Helsinki , Finland
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Strengell S, Keyriläinen J, Suortti P, Bayat S, Sovijärvi ARA, Porra L. Radiation dose and image quality in K-edge subtraction computed tomography of lung in vivo. J Synchrotron Radiat 2014; 21:1305-1313. [PMID: 25343799 DOI: 10.1107/s160057751401697x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/23/2014] [Indexed: 06/04/2023]
Abstract
K-edge subtraction computed tomography (KES-CT) allows simultaneous imaging of both structural features and regional distribution of contrast elements inside an organ. Using this technique, regional lung ventilation and blood volume distributions can be measured experimentally in vivo. In order for this imaging technology to be applicable in humans, it is crucial to minimize exposure to ionizing radiation with little compromise in image quality. The goal of this study was to assess the changes in signal-to-noise ratio (SNR) of KES-CT lung images as a function of radiation dose. The experiments were performed in anesthetized and ventilated rabbits using inhaled xenon gas in O2 at two concentrations: 20% and 70%. Radiation dose, defined as air kerma (Ka), was measured free-in-air and in a 16 cm polymethyl methacrylate phantom with a cylindrical ionization chamber. The dose free-in-air was varied from 2.7 mGy to 8.0 Gy. SNR in the images of xenon in air spaces was above the Rose criterion (SNR > 5) when Ka was over 400 mGy with 20% xenon, and over 40 mGy with 70% xenon. Although in human thorax attenuation is higher, based on these findings it is estimated that, by optimizing the imaging sequence and reconstruction algorithms, the radiation dose could be further reduced to clinically acceptable levels.
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Affiliation(s)
- S Strengell
- Department of Physics, University of Helsinki, Helsinki 00370, Finland
| | - J Keyriläinen
- Department of Oncology, Helsinki University Central Hospital, Helsinki, Finland
| | - P Suortti
- Department of Physics, University of Helsinki, Helsinki 00370, Finland
| | - S Bayat
- Université de Picardie Jules Verne, Inserm U1105 and CHU Amiens, France
| | - A R A Sovijärvi
- Department of Clinical Physiology and Nuclear Medicine, Helsinki University Central Hospital, Helsinki, Finland
| | - L Porra
- Department of Physics, University of Helsinki, Helsinki 00370, Finland
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Korhonen J, Kapanen M, Keyriläinen J, Seppälä T, Tenhunen M. MRI-Only Based RTP Workflow for Prostate Cancer Patients. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.2630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Korhonen J, Kapanen M, Keyriläinen J, Seppälä T, Tenhunen M. A dual model HU conversion from MRI intensity values within and outside of bone segment for MRI-based radiotherapy treatment planning of prostate cancer. Med Phys 2014; 41:011704. [PMID: 24387496 DOI: 10.1118/1.4842575] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The lack of electron density information in magnetic resonance images (MRI) poses a major challenge for MRI-based radiotherapy treatment planning (RTP). In this study the authors convert MRI intensity values into Hounsfield units (HUs) in the male pelvis and thus enable accurate MRI-based RTP for prostate cancer patients with varying tissue anatomy and body fat contents. METHODS T1/T2*-weighted MRI intensity values and standard computed tomography (CT) image HUs in the male pelvis were analyzed using image data of 10 prostate cancer patients. The collected data were utilized to generate a dual model HU conversion technique from MRI intensity values of the single image set separately within and outside of contoured pelvic bones. Within the bone segment local MRI intensity values were converted to HUs by applying a second-order polynomial model. This model was tuned for each patient by two patient-specific adjustments: MR signal normalization to correct shifts in absolute intensity level and application of a cutoff value to accurately represent low density bony tissue HUs. For soft tissues, such as fat and muscle, located outside of the bone contours, a threshold-based segmentation method without requirements for any patient-specific adjustments was introduced to convert MRI intensity values into HUs. The dual model HU conversion technique was implemented by constructing pseudo-CT images for 10 other prostate cancer patients. The feasibility of these images for RTP was evaluated by comparing HUs in the generated pseudo-CT images with those in standard CT images, and by determining deviations in MRI-based dose distributions compared to those in CT images with 7-field intensity modulated radiation therapy (IMRT) with the anisotropic analytical algorithm and 360° volumetric-modulated arc therapy (VMAT) with the Voxel Monte Carlo algorithm. RESULTS The average HU differences between the constructed pseudo-CT images and standard CT images of each test patient ranged from -2 to 5 HUs and from 22 to 78 HUs in soft and bony tissues, respectively. The average local absolute value differences were 11 HUs in soft tissues and 99 HUs in bones. The planning target volume doses (volumes 95%, 50%, 5%) in the pseudo-CT images were within 0.8% compared to those in CT images in all of the 20 treatment plans. The average deviation was 0.3%. With all the test patients over 94% (IMRT) and 92% (VMAT) of dose points within body (lower than 10% of maximum dose suppressed) passed the 1 mm and 1% 2D gamma index criterion. The statistical tests (t- and F-tests) showed significantly improved (p ≤ 0.05) HU and dose calculation accuracies with the soft tissue conversion method instead of homogeneous representation of these tissues in MRI-based RTP images. CONCLUSIONS This study indicates that it is possible to construct high quality pseudo-CT images by converting the intensity values of a single MRI series into HUs in the male pelvis, and to use these images for accurate MRI-based prostate RTP dose calculations.
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Affiliation(s)
- Juha Korhonen
- Clinical Research Institute Helsinki University Central Hospital Ltd., POB-700, 00029 HUS, Finland and Department of Oncology, Helsinki University Central Hospital, POB-180, 00029 HUS, Finland
| | - Mika Kapanen
- Clinical Research Institute Helsinki University Central Hospital Ltd., POB-700, 00029 HUS, Finland; Department of Oncology, Helsinki University Central Hospital, POB-180, 00029 HUS, Finland; and Department of Medical Physics, Tampere University Hospital, POB-2000, 33521 Tampere, Finland
| | - Jani Keyriläinen
- Department of Oncology, Helsinki University Central Hospital, POB-180, 00029 HUS, Finland
| | - Tiina Seppälä
- Department of Oncology, Helsinki University Central Hospital, POB-180, 00029 HUS, Finland
| | - Mikko Tenhunen
- Department of Oncology, Helsinki University Central Hospital, POB-180, 00029 HUS, Finland
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Korhonen J, Kapanen M, Keyriläinen J, Seppälä T, Tuomikoski L, Tenhunen M. Influence of MRI-based bone outline definition errors on external radiotherapy dose calculation accuracy in heterogeneous pseudo-CT images of prostate cancer patients. Acta Oncol 2014; 53:1100-6. [PMID: 24998163 DOI: 10.3109/0284186x.2014.929737] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND This work evaluates influences of susceptibility-induced bone outline shift and perturbations, and bone segmentation errors on external radiotherapy dose calculation accuracy in magnetic resonance imaging (MRI)-based pseudo-computed tomography (CT) images of the male pelvis. MATERIAL AND METHODS T₁/T₂*-weighted fast gradient echo, T₁-weighted spin echo and T₂-weighted fast spin echo images were used in bone detection investigation. Bone edge location and bone diameter in MRI were evaluated by comparing those in the images with actual physical measurements of fresh deer bones positioned in a gelatine phantom. Dose calculation accuracy in pseudo-CT images was investigated for 15 prostate cancer patients. Bone outlines in T₁/T₂*-weighted images were contoured and additional segmentation errors were simulated by expanding and contracting the bone contours with 1 mm spacing. Heterogeneous pseudo-CT images were constructed by adopting a technique transforming the MRI intensity values into Hounsfield units with separate conversion models within and outside of bone segment. RESULTS Bone edges and diameter in the phantom were illustrated correctly within a 1 mm-pixel size in MRI. Each 1 mm-sized systematic error in bone segment resulted in roughly 0.4% change to the prostate dose level in the pseudo-CT images. The prostate average (range) dose levels in pseudo-CT images with additional systematic bone segmentation errors of -2 mm, 0 mm and 2 mm were 0.5% (-0.5-1.4%), -0.2% (-1.0-0.7%), and -0.9% (-1.8-0.0%) compared to those in CT images, respectively, in volumetric modulated arc therapy treatment plans calculated by Monte Carlo algorithm. CONCLUSIONS Susceptibility-induced bone outline shift and perturbations do not result in substantial uncertainty for MRI-based dose calculation. Dose consistency of 2% can be achieved reliably for the prostate if heterogeneous pseudo-CT images are constructed with ≤± 2 mm systematic error in bone segment.
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Affiliation(s)
- Juha Korhonen
- Clinical Research Institute Helsinki University Central Hospital Ltd , Helsinki , Finland
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Ålander E, Visapää H, Kouri M, Keyriläinen J, Saarilahti K, Tenhunen M. Gold seed fiducials in analysis of linear and rotational displacement of the prostate bed. Radiother Oncol 2013; 110:256-60. [PMID: 24332022 DOI: 10.1016/j.radonc.2013.10.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 10/25/2013] [Accepted: 10/26/2013] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE This study aimed to investigate the magnitude of interfraction prostate bed motion during radiotherapy using both the implanted gold seed fiducials and the soft tissue registration and to define reasonable planning target volume (PTV) margins for different localization methods. MATERIAL AND METHODS Thirteen prostatectomized prostate cancer patients, after implanting four gold seed fiducials into their prostate bed, were imaged daily using a pretreatment cone-beam computed tomography (CBCT). Linear and the rotational prostate bed motion (PBM) was measured for 466 CBCTs. RESULTS The linear PBM mean and standard deviation values in millimeters are 0.0 ± 0.5, 0.7 ± 2.1 and 0.8 ± 1.6 in the LR, SI and AP axes, respectively. In 20% of the fractions the rotation of the prostate bed in sagittal plane exceeds ±6° and in 5% it exceeds ±10° from the position on the planning CT. In the transversal and coronal planes 1% and 2% of it exceeds ±6°. The PTV margins are 2.4, 6.5 and 6.6mm in the LR, SI and AP axes, respectively, if imaging is performed for the first three treatment fractions. CONCLUSION The linear PBM is largest in the SI and AP axis, whereas the rotation is largest in the sagittal plane. Bone localization during the first three treatment fractions can reduce PTV margins by 52%, 18% and 10% in the LR, SI and AP axes, respectively, whereas in daily CBCT the use of the gold seed fiducials seems profitable.
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Affiliation(s)
- Elisa Ålander
- Helsinki University Central Hospital, Department of Oncology, Finland.
| | - Harri Visapää
- Helsinki University Central Hospital, Department of Oncology, Finland
| | - Mauri Kouri
- Helsinki University Central Hospital, Department of Oncology, Finland
| | - Jani Keyriläinen
- Helsinki University Central Hospital, Department of Oncology, Finland
| | - Kauko Saarilahti
- Helsinki University Central Hospital, Department of Oncology, Finland
| | - Mikko Tenhunen
- Helsinki University Central Hospital, Department of Oncology, Finland
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Tuomikoski L, Korhonen J, Collan J, Keyriläinen J, Visapää H, Sairanen J, Saarilahti K, Tenhunen M. Implementation of adaptive radiation therapy for urinary bladder carcinoma: imaging, planning and image guidance. Acta Oncol 2013; 52:1451-7. [PMID: 23968261 DOI: 10.3109/0284186x.2013.813639] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Adaptive radiation therapy (ART) for urinary bladder cancer has emerged as a promising alternative to conventional RT with potential to minimize radiation-induced toxicity to healthy tissues. In this work we have studied bladder volume variations and their effect on healthy bladder dose sparing and intrafractional margins, in order to refine our ART strategy. MATERIAL AND METHODS An online ART treatment strategy was followed for five patients with urinary bladder cancer with the tumors demarcated using Lipiodol(®). A library of 3-4 predefined treatment plans for each patient was created based on four successive computed tomography (CT) scans. Cone beam CT (CBCT) images were acquired before each treatment fraction and after the treatment at least weekly. In partial bladder treatment the sparing of the healthy part of the bladder was investigated. The bladder wall displacements due to bladder filling were determined in three orthogonal directions (CC, AP, DEX-SIN) using the treatment planning CT scans. An ellipsoidal model was applied in order to find the theoretical maximum values for the bladder wall displacements. Moreover, the actual bladder filling rate during treatment was evaluated using the CBCT images. Results. In partial bladder treatment the volume of the bladder receiving high absorbed doses was generally smaller with a full than empty bladder. The estimation of the bladder volume and the upper limit for the intrafractional movement of the bladder wall could be represented with an ellipsoidal model with a reasonable accuracy. Observed maximum growth of bladder dimensions was less than 10 mm in all three orthogonal directions during 15 minute interval. CONCLUSION The use of Lipiodol contrast agent enables partial bladder treatment with reduced irradiation of the healthy bladder volume. The ellipsoidal bladder model can be used for the estimation of the bladder volume changes and the upper limit of the bladder wall movement during the treatment fraction.
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Affiliation(s)
- Laura Tuomikoski
- Department of Oncology, Helsinki University Central Hospital , Helsinki , Finland
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Ålander E, Visapää H, Keyriläinen J, Kouri M, Tenhunen M. EP-1272: Gold seed markers in prostate bed image-guided radiotherapy. Radiother Oncol 2013. [DOI: 10.1016/s0167-8140(15)33578-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Tuomikoski L, Collan J, Kapanen M, Keyriläinen J, Saarilahti K, Tenhunen M. PO-0906: Can signs of individual radiosensitivity be seen in salivary gland scintigraphy after head and neck radiotherapy? Radiother Oncol 2013. [DOI: 10.1016/s0167-8140(15)33212-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Laissue JA, Bartzsch S, Blattmann H, Bräuer-Krisch E, Bravin A, Dalléry D, Djonov V, Hanson AL, Hopewell JW, Kaser-Hotz B, Keyriläinen J, Laissue PP, Miura M, Serduc R, Siegbahn AE, Slatkin DN. Response of the rat spinal cord to X-ray microbeams. Radiother Oncol 2013; 106:106-11. [DOI: 10.1016/j.radonc.2012.12.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 12/07/2012] [Accepted: 12/11/2012] [Indexed: 11/26/2022]
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Korhonen J, Kapanen M, Keyriläinen J, Seppälä T, Tuomikoski L, Tenhunen M. Absorbed doses behind bones with MR image-based dose calculations for radiotherapy treatment planning. Med Phys 2012; 40:011701. [DOI: 10.1118/1.4769407] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Korhonen J, Kapanen M, Keyriläinen J, Seppälä T, Tuomikoski L, Tenhunen M. SU-E-J-54: Bone Detection in MR Images and Absorbed Dose in a Material Behind Bones in Radiotherapy. Med Phys 2012; 39:3664. [PMID: 28517612 DOI: 10.1118/1.4734889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To determine whether bones could be localized accurately by using MR images only in radiotherapy treatment planning. Furthermore, to measure absorbed dose in a material behind different parts of the bone, and to evaluate dose calculation error in a pseudo-CT image by assuming a single electron density for the bones. METHODS A dedicated phantom was constructed using fresh deer bones and gelatine. The accuracy of the bone edge location and the bone diameter in MR images were evaluated by comparing those in the images with the actual measures. The absorbed dose behind the bones was measured by a matrix detector at 6 and 15 MV. Thedose calculation error in the bulk density pseudo-CT image was quantified by comparing the calculation results with those obtained in a standard CT image by superposition and Monte Carlo algorithms (TPSs: Xio 4.60 and Monaco 3.00, Elekta CMS Software). RESULTS The examination of bone position revealed that the bones can be localized within a 1-mm-pixel-size in the MR images. The measured dose behind less than 2.5-cm-thick femur indicated that the absorbed dose behind the middle part of the bone is approximately one percentage unit (6 MV: 1.3%, 15 MV: 0.9%) smallerthan that of the physically narrower bone edge. The calculations illustrated that the bulk density pseudo-CT image used causes errors up to nearly 2% to the dose behind the middle part, but also, the edge of the femur. CONCLUSIONS This research ascertains that the bone localization is not a restrictive issue for radiotherapy treatment planning by using MR imageonly. The work indicates also that the decrease in absorbed dose is not necessarily dependent on the diameter of the bone. Future research shouldinvestigate the generation of more complex pseudo-CT images and the dosecalculations by using these. Supported by Elekta.
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Affiliation(s)
- J Korhonen
- Helsinki University Central Hospital, Department of Oncology, Helsinki, Finland
| | - M Kapanen
- Helsinki University Central Hospital, Department of Oncology, Helsinki, Finland
| | - J Keyriläinen
- Helsinki University Central Hospital, Department of Oncology, Helsinki, Finland
| | - T Seppälä
- Helsinki University Central Hospital, Department of Oncology, Helsinki, Finland
| | - L Tuomikoski
- Helsinki University Central Hospital, Department of Oncology, Helsinki, Finland
| | - M Tenhunen
- Helsinki University Central Hospital, Department of Oncology, Helsinki, Finland
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Keyriläinen J, Fernández M, Bravin A, Karjalainen-Lindsberg ML, Leidenius M, von Smitten K, Tenhunen M, Kangasmäki A, Sipilä P, Nemoz C, Virkkunen P, Suortti P. Comparison of in vitro breast cancer visibility in analyser-based computed tomography with histopathology, mammography, computed tomography and magnetic resonance imaging. J Synchrotron Radiat 2011; 18:689-696. [PMID: 21862846 DOI: 10.1107/s090904951102810x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 07/13/2011] [Indexed: 05/31/2023]
Abstract
High-resolution analyser-based X-ray imaging computed tomography (HR ABI-CT) findings on in vitro human breast cancer are compared with histopathology, mammography, computed tomography (CT) and magnetic resonance imaging. The HR ABI-CT images provided significantly better low-contrast visibility compared with the standard radiological images. Fine cancer structures indistinguishable and superimposed in mammograms were seen, and could be matched with the histopathological results. The mean glandular dose was less than 1 mGy in mammography and 12-13 mGy in CT and ABI-CT. The excellent visibility of in vitro breast cancer suggests that HR ABI-CT may have a valuable role in the future as an adjunct or even alternative to current breast diagnostics, when radiation dose is further decreased, and compact synchrotron radiation sources become available.
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Affiliation(s)
- Jani Keyriläinen
- Department of Physics, HUCH Cancer Center, Helsinki University Central Hospital, Helsinki, Finland.
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Tuomikoski L, Collan J, Keyriläinen J, Visapää H, Saarilahti K, Tenhunen M. Adaptive radiotherapy in muscle invasive urinary bladder cancer – An effective method to reduce the irradiated bowel volume. Radiother Oncol 2011; 99:61-6. [DOI: 10.1016/j.radonc.2011.02.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 01/13/2011] [Accepted: 02/17/2011] [Indexed: 11/30/2022]
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Coan P, Wagner A, Bravin A, Diemoz PC, Keyriläinen J, Mollenhauer J. In vivo x-ray phase contrast analyzer-based imaging for longitudinal osteoarthritis studies in guinea pigs. Phys Med Biol 2010; 55:7649-62. [PMID: 21113092 DOI: 10.1088/0031-9155/55/24/017] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Over the last two decades phase contrast x-ray imaging techniques have been extensively studied for applications in the biomedical field. Published results demonstrate the high capability of these imaging modalities of improving the image contrast of biological samples with respect to standard absorption-based radiography and routinely used clinical imaging techniques. A clear depiction of the anatomic structures and a more accurate disease diagnosis may be provided by using radiation doses comparable to or lower than those used in current clinical methods. In the literature many works show images of phantoms and excised biological samples proving the high sensitivity of the phase contrast imaging methods for in vitro investigations. In this scenario, the applications of the so-called analyzer-based x-ray imaging (ABI) phase contrast technique are particularly noteworthy. The objective of this work is to demonstrate the feasibility of in vivo x-ray ABI phase contrast imaging for biomedical applications and in particular with respect to joint anatomic depiction and osteoarthritis detection. ABI in planar and tomographic modes was performed in vivo on articular joints of guinea pigs in order to investigate the animals with respect to osteoarthritis by using highly monochromatic x-rays of 52 keV and a low noise detector with a pixel size of 47 × 47 µm(2). Images give strong evidence of the ability of ABI in depicting both anatomic structures in complex systems as living organisms and all known signs of osteoarthritis with high contrast, high spatial resolution and with an acceptable radiation dose. This paper presents the first proof of principle study of in vivo application of ABI. The technical challenges encountered when imaging an animal in vivo are discussed. This experimental study is an important step toward the study of clinical applications of phase contrast x-ray imaging techniques.
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Affiliation(s)
- Paola Coan
- Faculty of Medicine and Institute of Clinical Radiology, Ludwig-Maximilians University, Munich, Germany.
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Abstract
When an X-ray wave traverses an object, its amplitude and phase change, resulting in attenuation, interference, and refraction, and in phase-contrast X-ray imaging (PCI) these are converted to intensity changes. The relative change of the X-ray phase per unit path length is even orders of magnitude larger than that of the X-ray amplitude, so that the image contrast based on variation of the X-ray phase is potentially much stronger than the contrast based on X-ray amplitude (absorption contrast). An important medical application of PCI methods is soft-tissue imaging, where the absorption contrast is inherently weak. It is shown by in vitro examples that signs of malignant human breast tumor are enhanced in PCI images. Owing to the strong contrast, the radiation dose can be greatly reduced, so that a high-resolution phase-contrast X-ray tomography of the breast is possible with about 1 mGy mean glandular dose. Scattered radiation carries essential information on the atomic and molecular structure of the object, and particularly small-angle X-ray scattering can be used to trace cancer. The imaging methods developed at the synchrotron radiation facilities will become available in the clinical environment with the ongoing development of compact radiation sources, which produce intense X-ray beams of sufficient coherence. Several developments that are under way are described here.
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Affiliation(s)
- Jani Keyriläinen
- Department of Physics, HUCH Cancer Center, Helsinki University Central Hospital (HUCH), Helsinki, Finland
| | - Alberto Bravin
- Bio-medical Beamline ID17, European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - Manuel Fernández
- High Brilliance Beamline ID2, European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - Mikko Tenhunen
- Department of Physics, HUCH Cancer Center, Helsinki University Central Hospital (HUCH), Helsinki, Finland
| | - Pekka Virkkunen
- Department of Radiology, HUCH Cancer Center, Helsinki University Central Hospital (HUCH), Helsinki, Finland
| | - Pekka Suortti
- Department of Physics, University of Helsinki, Helsinki, Finland
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Fernández M, Suhonen H, Keyriläinen J, Bravin A, Fiedler S, Karjalainen-Lindsberg ML, Leidenius M, von Smitten K, Suortti P. USAXS and SAXS from cancer-bearing breast tissue samples. Eur J Radiol 2008; 68:S89-94. [DOI: 10.1016/j.ejrad.2008.04.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 04/25/2008] [Indexed: 10/21/2022]
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Régnard P, Bräuer-Krisch E, Troprès I, Keyriläinen J, Bravin A, Le Duc G. Enhancement of survival of 9L gliosarcoma bearing rats following intracerebral delivery of drugs in combination with microbeam radiation therapy. Eur J Radiol 2008; 68:S151-5. [DOI: 10.1016/j.ejrad.2008.04.049] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 04/28/2008] [Indexed: 11/28/2022]
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Keyriläinen J, Fernández M, Karjalainen-Lindsberg ML, Virkkunen P, Leidenius M, von Smitten K, Sipilä P, Fiedler S, Suhonen H, Suortti P, Bravin A. Toward High-Contrast Breast CT at Low Radiation Dose. Radiology 2008; 249:321-7. [PMID: 18796684 DOI: 10.1148/radiol.2491072129] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jani Keyriläinen
- Department of Oncology and Radiotherapy, Turku University Central Hospital, Savitehtaankatu 1, FIN-20521 Turku, Finland.
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Felici MD, Siegbahn EA, Spiga J, Hanson AL, Felici R, Ferrero C, Tartari A, Gambaccini M, Keyriläinen J, Bräuer-Krisch E, Randaccio P, Bravin A. Monte Carlo code comparison of dose delivery prediction for microbeam radiation therapy. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/102/1/012005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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39
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Suhonen H, Fernández M, Bravin A, Keyriläinen J, Suortti P. Refraction and scattering of X-rays in analyzer-based imaging. J Synchrotron Radiat 2007; 14:512-21. [PMID: 17960034 DOI: 10.1107/s0909049507044664] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 09/12/2007] [Indexed: 05/11/2023]
Abstract
A new algorithm is introduced for separation of the scattered and non-scattered parts of a monochromatic and well collimated synchrotron radiation beam transmitted through a sample and analyzed by reflection from a perfect crystal in the non-dispersive setting. The observed rocking curve is described by the Voigt function, which is a convolution of Lorentzian and Gaussian functions. For the actual fitting, pseudo-Voigtians are used. The fit yields the scaled integrated intensity (the effect of absorption), the center of the rocking curve (the effect of refraction), and the intensity of the transmitted beam is divided into the scattered and non-scattered parts. The algorithm is tested using samples that exhibit various degrees of refraction and scattering. Very close fits are achieved in an angular range that is 15 times the full width at half-maximum of the intrinsic rocking curve of the analyzer. The scattering part has long tails of Lorentzian shape owing to the ;long-slit geometry' of the set-up. Quantitative images of absorption, refraction and scattering are constructed and compared with results of earlier treatments. The portion of scattering and the second moment of the observed rocking curve both increase linearly with the sample thickness and yield identical maps of the effects of scattering. The effects of refraction are calculated using the geometrical optics approximation, and a good agreement with experiment is found. The fits with reduced number of data points (minimum number is five) yield closely the same results as fits to the full data set.
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Affiliation(s)
- Heikki Suhonen
- Department of Physical Sciences, PL 64, FIN-00014 Helsinki University, Finland.
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Bravin A, Keyriläinen J, Fernández M, Fiedler S, Nemoz C, Karjalainen-Lindsberg ML, Tenhunen M, Virkkunen P, Leidenius M, von Smitten K, Sipilä P, Suortti P. High-resolution CT by diffraction-enhanced x-ray imaging: mapping of breast tissue samples and comparison with their histo-pathology. Phys Med Biol 2007; 52:2197-211. [PMID: 17404464 DOI: 10.1088/0031-9155/52/8/011] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The aim of this study was to introduce high-resolution computed tomography (CT) of breast tumours using the diffraction-enhanced x-ray imaging (DEI) technique and to compare results with radiological and histo-pathological examinations. X-ray CT images of tumour-bearing breast tissue samples were acquired by monochromatic synchrotron radiation (SR). Due to the narrow beam and a large sample-to-detector distance scattering is rejected in the absorption contrast images (SR-CT). Large contrast enhancement is achieved by the use of the DEI-CT method, where the effects of refraction and scatter rejection are analysed by crystal optics. Clinical mammograms and CT images were recorded as reference material for a radiological examination. Three malignant and benign samples were studied in detail. Their radiographs were compared with optical images of stained histological sections. The DEI-CT images map accurately the morphology of the samples, including collagen strands and micro-calcifications of dimensions less than 0.1 mm. Histo-pathological examination and reading of the radiographs were done independently, and the conclusions were in general agreement. High-resolution DEI-CT images show strong contrast and permit visualization of details invisible in clinical radiographs. The radiation dose may be reduced by an order of magnitude without compromising image quality, which would make possible clinical in vivo DEI-CT with future compact SR sources.
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Affiliation(s)
- Alberto Bravin
- ID17, European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France.
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41
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Fernández M, Keyriläinen J, Serimaa R, Torkkeli M, Karjalainen-Lindsberg ML, Leidenius M, von Smitten K, Tenhunen M, Fiedler S, Bravin A, Weiss TM, Suortti P. Human breast cancerin vitro: matching histo-pathology with small-angle x-ray scattering and diffraction enhanced x-ray imaging. Phys Med Biol 2005; 50:2991-3006. [PMID: 15972976 DOI: 10.1088/0031-9155/50/13/002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Twenty-eight human breast tumour specimens were studied with small-angle x-ray scattering (SAXS), and 10 of those were imaged by the diffraction enhanced x-ray imaging (DEI) technique. The sample diameter was 20 mm and the thickness 1 mm. Two examples of ductal carcinoma are illustrated by histology images, DEI, and maps of the collagen d-spacing and scattered intensity in the Porod regime, which characterize the SAXS patterns from collagen-rich regions of the samples. Histo-pathology reveals the cancer-invaded regions, and the maps of the SAXS parameters show that in these regions the scattering signal differs significantly from scattering by the surrounding tissue, indicating a degradation of the collagen structure in the invaded regions. The DEI images show the borders between collagen and adipose tissue and provide a co-ordinate system for tissue mapping by SAXS. In addition, degradation of the collagen structure in an invaded region is revealed by fading contrast of the DEI refraction image. The 28 samples include fresh, defrosted tissue and formalin-fixed tissue. The d-values with their standard deviations are given. In the fresh samples there is a systematic 0.76% increase of the d-value in the invaded regions, averaged over 11 samples. Only intra-sample comparisons are made for the formalin-fixed samples, and with a long fixation time, the difference in the d-value stabilizes at about 0.7%. The correspondence between the DEI images, the SAXS maps and the histo-pathology suggests that definitive information on tumour growth and malignancy is obtained by combining these x-ray methods.
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Affiliation(s)
- Manuel Fernández
- Department of Physical Sciences, POB 64, FIN-00014 University of Helsinki, Finland.
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42
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Keyriläinen J, Fernández M, Fiedler S, Bravin A, Karjalainen-Lindsberg ML, Virkkunen P, Elo EM, Tenhunen M, Suortti P, Thomlinson W. Visualisation of calcifications and thin collagen strands in human breast tumour specimens by the diffraction-enhanced imaging technique: a comparison with conventional mammography and histology. Eur J Radiol 2005; 53:226-37. [PMID: 15664286 DOI: 10.1016/j.ejrad.2004.03.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2003] [Revised: 03/08/2004] [Accepted: 03/10/2004] [Indexed: 10/26/2022]
Abstract
Six excised human breast tissue specimens carrying benign and malignant tumours were examined with the diffraction-enhanced imaging technique. Diffraction-enhanced images were compared with diagnostic screen-film mammograms and the correlation with histological information of the specimens was established. The enhanced visibility of calcifications, some of which were smaller than 0.15 mm in diameter, is reported in detail. Fine details of the structures such as strands of collagen and contours between glandular and adipose tissue, which are barely visible at the contrast detection limit in the conventional absorption-based mammograms, are clearly visible in the diffraction-enhanced images. Microscopic study of the stained histopathological sections unequivocally confirms the correlation of the radiographic findings with the morphologic changes in specimens. An increased soft tissue contrast and a combination of information obtained with disparate diffraction-enhanced images provide better visibility of mammographically indistinguishable features. This kind of additional structural information of the breast tissue is required to improve assessment accuracy and earlier detection of the breast lesions. These advances in image quality make the method a very promising candidate for mammography.
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Affiliation(s)
- Jani Keyriläinen
- Department of Physical Sciences, University of Helsinki, Gustaf Hällströmin katu 2, FIN-00014 Helsinki, Finland.
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Pagot E, Fiedler S, Cloetens P, Bravin A, Coan P, Fezzaa K, Baruchel J, Härtwig J, von Smitten K, Leidenius M, Karjalainen-Lindsberg ML, Keyriläinen J. Quantitative comparison between two phase contrast techniques: diffraction enhanced imaging and phase propagation imaging. Phys Med Biol 2005; 50:709-24. [PMID: 15773629 DOI: 10.1088/0031-9155/50/4/010] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Two x-ray phase contrast imaging techniques are compared in a quantitative way for future mammographic applications: diffraction enhanced imaging (DEI) and phase propagation imaging (PPI). DEI involves, downstream of the sample, an analyser crystal acting as an angular filter for x-rays refracted by the sample. PPI simply uses the propagation (Fresnel diffraction) of the monochromatic and partially coherent x-ray beam over large distances. The information given by the two techniques is assessed by theoretical simulations and compared at the level of the experimental results for different kinds of samples (phantoms and real tissues). The imaging parameters such as the energy, the angular position of the analyser crystal in the DEI case or the sample to detector distance in the PPI case were varied in order to optimize the image quality in terms of contrast, visibility and figure of merit.
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Affiliation(s)
- Elodie Pagot
- European Synchrotron Radiation Facility, 6 rue Horowitz, BP220, F-38043 Grenoble, France.
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Fiedler S, Bravin A, Keyriläinen J, Fernández M, Suortti P, Thomlinson W, Tenhunen M, Virkkunen P, Karjalainen-Lindsberg M. Imaging lobular breast carcinoma: comparison of synchrotron radiation DEI-CT technique with clinical CT, mammography and histology. Phys Med Biol 2004; 49:175-88. [PMID: 15083665 DOI: 10.1088/0031-9155/49/2/001] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Different modalities for imaging cancer-bearing breast tissue samples are described and compared. The images include clinical mammograms and computed tomography (CT) images, CT images with partly coherent synchrotron radiation (SR), and CT and radiography images taken with SR using the diffraction enhanced imaging (DEI) method. The images are evaluated by a radiologist and compared with histopathological examination of the samples. Two cases of lobular carcinoma are studied in detail. The indications of cancer are very weak or invisible in the conventional images, but the morphological changes due to invasion of cancer become pronounced in the images taken by the DEI method. The strands penetrating adipose tissue are seen clearly in the DEI-CT images, and the histopathology confirms that some strands contain the so-called 'Indian file' formations of cancer cells. The radiation dose is carefully measured for each of the imaging modalities. The mean glandular dose (MGD) for 50% glandular breast tissue is about 1 mGy in conventional mammography and less than 0.25 mGy in projection DEI, while in the clinical CT imaging the MGD is very high, about 45 mGy. The entrance dose of 95 mGy in DEI-CT imaging gives rise to an MGD of 40 mGy, but the dose may be reduced by an order of magnitude, because the contrast is very large in most images.
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Affiliation(s)
- S Fiedler
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France
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Abstract
A new type of fine-rotation stage has been constructed and tested. It can be attached to standard goniometers used in X-ray and neutron crystallography. The device consists of a shaft and a bar that is fitted tightly to a hole traversing the shaft. The diameter of the shaft is 5 to 10 times larger than the diameter of the bar and the length of the bar is about 5 times larger than the height of the shaft. The bottom of the shaft is attached to the top plate of the goniometer and a goniometer head can be fitted to the other end of the shaft. The free end of the bar is pushed tangentially by a linear actuator to produce a torsion moment at the shaft. The dimensions and materials of the prototype were chosen such that a 1 mm bend of the bar corresponded to a torsion angle of the shaft of about 20 µrad. The rotation angle was measured using a double-crystal diffractometer in the non-dispersive setting, with MoKα1radiation from a fine-focus X-ray tube. Accurately known angular deviations were produced by refraction in a prism and the shifts in the rocking-curve position were measured. The measured torsion angle agreed within 4% with the value calculated from the elastic constants and dimensions of the device. The repeatability of the angle was ±20 nrad (0.004 arcsec).
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Fernández M, Keyriläinen J, Serimaa R, Torkkeli M, Karjalainen-Lindsberg ML, Tenhunen M, Thomlinson W, Urban V, Suortti P. Small-angle x-ray scattering studies of human breast tissue samples. Phys Med Biol 2002; 47:577-92. [PMID: 11900192 DOI: 10.1088/0031-9155/47/4/303] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Small-angle x-ray scattering (SAXS) patterns are recorded from thin breast tissue samples containing healthy and cancerous regions. The SAXS patterns are compared with histo-pathological observations. The information available from SAXS is reviewed, and a model for scattering from collagen is presented. Scattering patterns of collagen at regions far from the tumours are essentially different from those at tumours. The axial period of collagen fibrils is 65.0 +/- 0.1 nm in healthy regions, and 0.3 nm larger in cancer-invaded regions. The average intensity of scattering from cancerous regions is an order of magnitude higher than the intensity from healthy regions. This is interpreted to arise from an increase of the specific surface area of the scatterers, which is due to a disruption of the molecular and supra-molecular structures in cancerous regions and invasion of new types of cells. The differences of the SAXS patterns are large and distinctive enough to suggest that these phenomena may be utilized in mammography.
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Affiliation(s)
- M Fernández
- Department of Physics, University of Helsinki, Finland.
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Hernberg M, Virkkunen P, Maasilta P, Keyriläinen J, Blomqvist C, Bergh J, Wiklund T. Pulmonary toxicity after radiotherapy in primary breast cancer patients: results from a randomized chemotherapy study. Int J Radiat Oncol Biol Phys 2002; 52:128-36. [PMID: 11777630 DOI: 10.1016/s0360-3016(01)01760-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE Pulmonary toxicity was prospectively evaluated within a randomized trial for breast cancer patients at high risk for relapse, who postoperatively received as adjuvant therapy either 9 cycles of tailored chemotherapy (20 patients) (cyclophosphamide, epirubicin, 5-fluorouracil [FEC]) or standard FEC x 3 followed by high-dose chemotherapy (cyclophosphamide, thiotepa, carboplatin [CTCb]) supported by peripheral blood stem cell transplantation (14 patients). After high-dose chemotherapy or tailored FEC, all patients received locoregional radiotherapy (50 Gy/5 weeks), plus tamoxifen for 5 years. METHODS AND MATERIALS Lung function tests (FVC, FEV1, and DL(CO)) were performed before chemotherapy and 9 months after radiotherapy. Computed tomography of the lungs was performed before radiotherapy and 6 weeks, 3 months, and 9 months after radiotherapy. RESULTS Clinical signs of suspected pneumonitis were noted in 29% of patients, but only 1 patient needed symptomatic therapy. Radiologic changes were detected in 68% of patients, and they were most frequent at 3 months after radiotherapy. FVC decreased in both groups (tailored FEC: mean difference, -6.5%, p = 0.0005; CTCb: -2.0%, p = 0.21; tailored FEC vs. CTCb: -4.5%, p = 0.05). DL(CO) decreased significantly in both groups (tailored FEC: mean difference, -11.2%, p < 0.0001; CTCb: -5.6%, p = 0.02; tailored FEC vs. CTCb: -5.6%, p = 0.07). FEV1 decreased by 7.3% in patients treated with tailored FEC (p < 0.0001) and by 2.5% in patients treated with CTCb (p = 0.03) (tailored FEC vs. CTCb: 3.7%, p = 0.08). CONCLUSIONS Changes in pulmonary function were thus detected in both groups, although to a greater extent in the tailored FEC group. The clinical significance of these findings should be balanced carefully against the improved, statistically significant relapse-free survival achieved with the tailored FEC regimen compared to high-dose CTCb + peripheral blood stem cell transplantation (PSCT).
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Affiliation(s)
- Micaela Hernberg
- Department of Oncology, Helsinki University Central Hospital, Helsinki, Finland.
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