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Renkamp CK, Eulenstein D, Sebald M, Schlüter F, Buchele C, Rippke C, Debus J, Klüter S. Evaluation of 2D ion chamber arrays for patient specific quality assurance using a static phantom at a 0.35 T MR-Linac. Z Med Phys 2024:S0939-3889(23)00150-2. [PMID: 38184375 DOI: 10.1016/j.zemedi.2023.12.003] [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: 02/27/2023] [Revised: 10/31/2023] [Accepted: 12/18/2023] [Indexed: 01/08/2024]
Abstract
INTRODUCTION Patient specific quality assurance (QA) in MR-Linacs can be performed with MR-compatible ion chamber arrays. However, the presence of a static magnetic field can alter the angular response of such arrays substantially. This works investigates the suitability of two ion chamber arrays, an air-filled and a liquid-filled array, for patient specific QA at a 0.35 T MR-Linac using a static phantom. METHODS In order to study the angular response, the two arrays were placed in a static, solid phantom and irradiated with 9.96 × 9.96 cm2 fields every 10° beam angle at a 0.35 T MR-Linac. Measurements were compared to the TPS calculated dose in terms of gamma passing rate and relative dose to the central chamber. 20 patient specific quality assurance plans were measured using the liquid-filled array. RESULTS The air-filled array showed asymmetric angular response changes of central chamber dose of up to 18% and down to local 3 mm / 3% gamma rates of 20%, while only minor differences within 3% (excluding parallel irradiation and beams through the couch edges) were found for the liquid-filled ion chamber array without rotating the phantom. Patient plan QA using the liquid-filled array yielded a median local 3 mm / 3% 3D gamma passing rate of 99.8% (range 96.9%-100%). CONCLUSION A liquid-filled ionization chamber array in combination with a static phantom can be used for efficient patient specific plan QA in a single measurement set-up in a 0.35 T MR-Linac, while the air-filled ion chamber array phantom shows large angular response changes and has its limitations regarding patient specific QA measurements.
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Affiliation(s)
- C K Renkamp
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg, Germany.
| | | | - M Sebald
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg, Germany
| | - F Schlüter
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg, Germany
| | - C Buchele
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg, Germany; Medical Faculty, University of Heidelberg, Heidelberg, Germany
| | - C Rippke
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg, Germany; Medical Faculty, University of Heidelberg, Heidelberg, Germany
| | - J Debus
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg, Germany; Medical Faculty, University of Heidelberg, Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany; National Center for Tumor diseases (NCT), Heidelberg, Germany; Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; German Cancer Consortium (DKTK), Core-Center Heidelberg, Heidelberg, Germany
| | - S Klüter
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany; Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg, Germany
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Klavsen MF, Ankjærgaard C, Boye K, Behrens CP, Vogelius IR, Ehrbar S, Baumgartl M, Rippke C, Buchele C, Renkamp CK, Santurio GV, Andersen CE. Accumulated dose implications from systematic dose-rate transients in gated treatments with Viewray MRIdian accelerators. Biomed Phys Eng Express 2023; 9:065001. [PMID: 37591227 DOI: 10.1088/2057-1976/acf138] [Citation(s) in RCA: 1] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 08/17/2023] [Indexed: 08/19/2023]
Abstract
The combination of magnetic resonance (MR) imaging and linear accelerators (linacs) into MR-Linacs enables continuous MR imaging and advanced gated treatments of patients. Previously, a dose-rate transient (∼8% reduced dose rate during the initial 0.5 s of each beam) was identified for a Viewray MRIdian MR-Linac (Klavsenet al2022Radiation Measurement106759). Here, the dose-rate transient is studied in more detail at four linacs of the same type at different hospitals. The implications of dose-rate transients were examined for gated treatments. The dose-rate transients were investigated using dose-per pulse measurements with organic plastic scintillators in three experiments: (i) A gated treatment with the scintillator placed in a moving target in a dynamic phantom, (ii) a gated treatment with the same dynamic conditions but with the scintillator placed in a stationary target, and (iii) measurements in a water-equivalent material to examine beam quality deviations at a dose-per-pulse basis. Gated treatments (i) compared with non-gated treatments with a static target in the same setup showed a broadening of accumulated dose profiles due to motion (dose smearing). The linac with the largest dose-rate transient had a reduced accumulated dose of up to (3.1 ± 0.65) % in the center of the PTV due to the combined dose smearing and dose-rate transient effect. Dose-rate transients were found to vary between different machines. Two MR-Linacs showed initial dose-rate transients that could not be identified from conventional linearity tests. The source of the transients includes an initial change in photon fluence rate and an initial change in x-ray beam quality. For gated treatments, this caused a reduction of more than 1% dose delivered at the central part of the beam for the studied, cyclic-motion treatment plan. Quality assurance of this effect should be considered when gated treatment with the Viewray MRIdian is implemented clinically.
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Affiliation(s)
- M F Klavsen
- DTU Health Tech, Technical University of Denmark, Roskilde, Denmark
| | - C Ankjærgaard
- DTU Health Tech, Technical University of Denmark, Roskilde, Denmark
| | - K Boye
- Dept. of Oncology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
| | - C P Behrens
- DTU Health Tech, Technical University of Denmark, Roskilde, Denmark
- Dept. of Oncology, Copenhagen University Hospital-Herlev and Gentofte, Copenhagen, Denmark
| | - I R Vogelius
- Dept. of Oncology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen- Copenhagen, Denmark
| | - S Ehrbar
- Dept. of Radiation Oncology, University Hospital Zürich and University of Zürich, Zürich, Switzerland
| | - M Baumgartl
- Dept. of Radiation Oncology, University Hospital Zürich and University of Zürich, Zürich, Switzerland
| | - C Rippke
- Dept. of Oncology, University Hospital Heidelberg, Heidelberg, Germany
| | - C Buchele
- Dept. of Oncology, University Hospital Heidelberg, Heidelberg, Germany
| | - C K Renkamp
- Dept. of Oncology, University Hospital Heidelberg, Heidelberg, Germany
| | - G V Santurio
- Dept. of Oncology, Copenhagen University Hospital-Herlev and Gentofte, Copenhagen, Denmark
| | - C E Andersen
- DTU Health Tech, Technical University of Denmark, Roskilde, Denmark
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Elter A, Rippke C, Johnen W, Mann P, Hellwich E, Schwahofer A, Dorsch S, Buchele C, Klüter S, Karger CP. End-to-end test for fractionated online adaptive MR-guided radiotherapy using a deformable anthropomorphic pelvis phantom. Phys Med Biol 2021; 66. [PMID: 34845991 DOI: 10.1088/1361-6560/ac3e0c] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/29/2021] [Indexed: 11/12/2022]
Abstract
Objective.In MR-guided radiotherapy (MRgRT) for prostate cancer treatments inter-fractional anatomy changes such as bladder and rectum fillings may be corrected by an online adaption of the treatment plan. To clinically implement such complex treatment procedures, however, specific end-to-end tests are required that are able to validate the overall accuracy of all treatment steps from pre-treatment imaging to dose delivery.Approach.In this study, an end-to-end test of a fractionated and online adapted MRgRT prostate irradiation was performed using the so-called ADAM-PETer phantom. The phantom was adapted to perform 3D polymer gel (PG) dosimetry in the prostate and rectum. Furthermore, thermoluminescence detectors (TLDs) were placed at the center and on the surface of the prostate for additional dose measurements as well as for an external dose renormalization of the PG. For the end-to-end test, a total of five online adapted irradiations were applied in sequence with different bladder and rectum fillings, respectively.Main results.A good agreement of measured and planned dose was found represented by highγ-index passing rates (3%/3mmcriterion) of the PG evaluation of98.9%in the prostate and93.7%in the rectum. TLDs used for PG renormalization at the center of the prostate showed a deviation of-2.3%.Significance.The presented end-to-end test, which allows for 3D dose verification in the prostate and rectum, demonstrates the feasibility and accuracy of fractionated and online-adapted prostate irradiations in presence of inter-fractional anatomy changes. Such tests are of high clinical importance for the commissioning of new image-guided treatment procedures such as online adaptive MRgRT.
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Affiliation(s)
- A Elter
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.,National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - C Rippke
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany.,Department of Radiation Oncology, University Hospital Heidelberg, Heidelberg, Germany.,Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - W Johnen
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - P Mann
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - E Hellwich
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - A Schwahofer
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - S Dorsch
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - C Buchele
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany.,Department of Radiation Oncology, University Hospital Heidelberg, Heidelberg, Germany.,Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - S Klüter
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany.,Department of Radiation Oncology, University Hospital Heidelberg, Heidelberg, Germany
| | - C P Karger
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
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Regnery S, Buchele C, Weykamp F, Hoegen P, Eichkorn T, Held T, Rippke C, Klüter S, Rademacher J, Debus J, Adeberg S, Hörner-Rieber J. PD-0873 Daily online adaption in MR-guided pulmonary SBRT: niche or new standard? Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)07152-8] [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: 10/20/2022]
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Weykamp F, Hoegen P, Klüter S, Renkamp K, König L, Seidensaal K, Regnery S, Liermann J, Rippke C, Koerber S, Buchele C, Debus J, Hörner-Rieber J. PO-1232 Magnetic resonance-guided stereotactic body radiotherapy of liver tumors: Initial clinical experience and patient-reported outcomes. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)07683-0] [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: 11/17/2022]
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Herder-Wagner C, Weykamp F, Regnery S, Hoegen P, Renkamp C, Liermann J, Rippke C, Koerber S, König L, Buchele C, Klüter S, Debus J, Hörner-Rieber J. PO-1502 Stereotactic body radiotherapy of lymph node metastases under MR-guidance. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)07953-6] [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: 11/25/2022]
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Hoegen P, Spindeldreier CK, Buchele C, Rippke C, Regnery S, Weykamp F, Klüter S, Debus J, Hörner-Rieber J. [Magnetic-resonance-guided radiotherapy : The beginning of a new era in radiation oncology?]. Radiologe 2021; 61:13-20. [PMID: 33052442 DOI: 10.1007/s00117-020-00761-8] [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] [Indexed: 12/18/2022]
Abstract
CLINICAL ISSUE Image-guided radiotherapy (IGRT) using X‑rays and cone-beam computed tomography (CT) has fostered precision radiotherapy. However, inter- and intrafractional variations of target volume position and organs at risk still limit target volume dose and sparing of radiosensitive organs at risk. METHODOLOGICAL INNOVATIONS Hybrid machines directly combining linear accelerators and magnetic resonance (MR) imaging allow for live imaging during radiotherapy. PERFORMANCE Besides highly improved soft tissue contrast, MR-linacs enable online, on-table adaptive radiotherapy. Thus, adaptation of the treatment plan to the anatomy of the day, dose escalation and superior sparing of organs at risk become possible. ACHIEVEMENTS This article summarizes the underlying intention for the development of MR-guided radiotherapy, technical innovations and challenges as well as the current state-of-the-art. Potential clinical benefits and future developments are discussed. PRACTICAL RECOMMENDATIONS Increasing availability of MR imaging at linear accelerators calls for the ability to review and interpret MR images. Therefore, close collaborations of diagnostic radiologists and radiation oncologists are mandatory to foster this fascinating technique.
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Affiliation(s)
- P Hoegen
- Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.,Heidelberger Institut für Radiooncology (HIRO), Heidelberg, Deutschland.,Nationales Centrum für Tumorerkrankungen (NCT), Heidelberg, Deutschland.,Clinical Cooperation Unit Radiation Oncology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Deutschland
| | - C K Spindeldreier
- Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.,Heidelberger Institut für Radiooncology (HIRO), Heidelberg, Deutschland
| | - C Buchele
- Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.,Heidelberger Institut für Radiooncology (HIRO), Heidelberg, Deutschland
| | - C Rippke
- Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.,Heidelberger Institut für Radiooncology (HIRO), Heidelberg, Deutschland
| | - S Regnery
- Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.,Heidelberger Institut für Radiooncology (HIRO), Heidelberg, Deutschland.,Nationales Centrum für Tumorerkrankungen (NCT), Heidelberg, Deutschland
| | - F Weykamp
- Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.,Heidelberger Institut für Radiooncology (HIRO), Heidelberg, Deutschland.,Nationales Centrum für Tumorerkrankungen (NCT), Heidelberg, Deutschland
| | - S Klüter
- Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.,Heidelberger Institut für Radiooncology (HIRO), Heidelberg, Deutschland
| | - J Debus
- Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.,Heidelberger Institut für Radiooncology (HIRO), Heidelberg, Deutschland.,Nationales Centrum für Tumorerkrankungen (NCT), Heidelberg, Deutschland.,Clinical Cooperation Unit Radiation Oncology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Deutschland.,Heidelberger Ionenstrahl-Therapiezentrum (HIT), Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland.,Standort Heidelberg, Deutsches Konsortium für Translationale Krebsforschung (DKTK), Heidelberg, Deutschland
| | - J Hörner-Rieber
- Klinik für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland. .,Heidelberger Institut für Radiooncology (HIRO), Heidelberg, Deutschland. .,Nationales Centrum für Tumorerkrankungen (NCT), Heidelberg, Deutschland. .,Clinical Cooperation Unit Radiation Oncology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Deutschland.
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