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Liang X, Li P, Wu Q. A novel AP/PA total body irradiation technique using abutting IMRT fields at extended SSD. J Appl Clin Med Phys 2024; 25:e14213. [PMID: 38425126 PMCID: PMC11005982 DOI: 10.1002/acm2.14213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 03/02/2024] Open
Abstract
PURPOSE To develop a Total Body Irradiation (TBI) technique using IMRT at extended SSD that can be performed in any size Linac room. METHODS Patients studied were placed on a platform close to the floor, directly under the gantry with cranial-caudal axis parallel to the gantry rotation plane and at SSD ∼200 cm. Two abutting fields with the same external isocenter at gantry angles of ±21˚, collimator angle of 90˚, and field size of 25 × 40 cm2 are employed for both supine and prone positions. An iterative optimization algorithm was developed to generate a uniform dose at the patient mid-plane with adequate shielding to critical organs such as lungs and kidneys. The technique was validated in both phantom and patient CT images for treatment planning, and dose measurement and QA were performed in phantom. RESULTS A uniform dose distribution in the mid-plane within ±5% of the prescription dose was reached after a few iterations. This was confirmed with ion-chamber measurements in phantom. The mean dose to lungs and kidneys can be adjusted according to clinical requirements and can be as low as ∼25% of the prescription dose. For a typical prescription dose of 200 cGy/fraction, the total MU was ∼2400/1200 for the superior/inferior field. The overall treatment time for both supine/prone positions was ∼54 min to meet the maximum absorbed dose rate criteria of 15 cGy/min. IMRT QA with portal dosimetry shows excellent agreement. CONCLUSIONS We have developed a promising TBI technique using abutting IMRT fields at extended SSD. The patient is in a comfortable recumbent position with good reproducibility and less motion during treatment. An additional benefit of this technique is that full 3D dose distribution is available from the TPS with a DVH summary for organs of interest. The technique allows precise sparing of lungs and kidneys and can be executed in any linac room.
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Affiliation(s)
- Xiaomin Liang
- Medical Physics Graduate ProgramDuke Kunshan UniversityKunshanJiangsuChina
| | - Peixiong Li
- Medical Physics Graduate ProgramDuke Kunshan UniversityKunshanJiangsuChina
| | - Qiuwen Wu
- Department of Radiation OncologyDuke University Medical CenterDurhamNorth CarolinaUSA
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Hansen AT, Rose HK, Yates ES, Hansen J, Petersen JB. Two compound techniques for total body irradiation. Tech Innov Patient Support Radiat Oncol 2021; 21:1-7. [PMID: 34977366 PMCID: PMC8683645 DOI: 10.1016/j.tipsro.2021.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 11/10/2021] [Accepted: 11/30/2021] [Indexed: 01/21/2023] Open
Abstract
INTRODUCTION Total body irradiation (TBI) is an important treatment modality that is used in combination with chemotherapy in many stem cell transplantation protocols. Therefore, the quality of the irradiation is important. Two techniques for planning and delivering TBI are presented and compared. METHODS AND MATERIALS The technique named ExIMRT is a combination of manually shaped conventional fields from an extended SSD and isocentric IMRT fields. The technique named ExVMAT is a combination of conventional and IMRT fields from an extended SSD and isocentric VMAT fields. Dosimetric data from 32 patients who were planned and treated according to one of the two techniques were compared. RESULTS When comparing the two techniques, it is determined that the ExVMAT technique is able to significantly reduce the mean total volume overdosed by 120% from 408 to 12 cm3. The dose covering 98% of the total lung volume is significantly increased by this technique from a mean of 9.7 Gy to 10.3 Gy. Additionally, the dose covering 2% of the total kidney volume is significantly decreased from a mean of 12.8 to 12.5 Gy. Furthermore, the population-based variance of the median dose to the total lung volume, the heart and the volume of the body prescribed to 12.5 Gy is significantly reduced. The results are obtained without compromising overall treatment quality as treatment time or dose rate to the lungs. CONCLUSION Using the ExVMAT technique, a superior dose distribution can be delivered both from a patient and a population perspective compared to the ExIMRT technique.
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Affiliation(s)
- Anders T. Hansen
- Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark,Corresponding author at: Department of Medical Physics, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark.
| | - Hanne K. Rose
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Esben S. Yates
- Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark
| | - Jolanta Hansen
- Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark
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Duncan-Gelder P, Moggré A, Cousins A, Wilder B, Marsh S. Accurate dosimetric measurement of large extended SSD fields for comparison to TPS models. Phys Med 2021; 84:220-227. [PMID: 33741247 DOI: 10.1016/j.ejmp.2021.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/27/2021] [Accepted: 03/01/2021] [Indexed: 10/21/2022] Open
Abstract
PURPOSE There is little evidence in the literature which quantifies the accuracy of Treatment Planning Systems (TPSs) using large fields at extended SSD (eSSD). This paper introduces the approach taken at Christchurch Hospital, New Zealand to validate the use of the Monaco TPS for Total Body Irradiation (TBI) treatments. METHODS A purpose-built device for allowing precise movements of block-like phantoms called a Phantom Mobility Device (PMD) was used for collecting measurements at eSSD. These measurements were used for determining the ability of the Monaco TPS (originally validated for SSDs between 80 and 110 cm) to accurately model dose distributions for TBI treatments at Christchurch Hospital on either treatment machine one (T1) or two (T2) with SSD values of 341 and 432.6 and clinically useful field sizes of 120 and 170 cm, respectively. RESULTS We found that within the limits of measurement uncertainty the PMD contributed no determinable scatter to the measurements and proved a reliable approach for eSSD dose measurements. Additionally, by applying depth and off-axis distance constraints of use for TPS information it is possible to use the existing Monaco CCC model at eSSD for block phantom geometries. Dose Difference (DD) analysis showed a clinically acceptable agreement between the CCC model and measured data over a range of depths and off-axis distances. CONCLUSIONS The PMD was determined to be a useful tool for accurate measurement of extended SSD treatment fields. Monaco TPS CCC model agreed well for block phantoms so future comparisons to anthropomorphic phantoms or patient data are feasible.
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Affiliation(s)
| | - Alicia Moggré
- University of Canterbury and Canterbury District Health Board, New Zealand.
| | - Andrew Cousins
- University of Canterbury and Canterbury District Health Board, New Zealand.
| | - Benjamin Wilder
- University of Canterbury and Canterbury District Health Board, New Zealand.
| | - Steven Marsh
- University of Canterbury and Canterbury District Health Board, New Zealand.
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Lamichhane N, Studenski MT. Improving TBI lung dose calculations: Can the treatment planning system help? Med Dosim 2021; 45:168-171. [PMID: 31727550 DOI: 10.1016/j.meddos.2019.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 09/09/2019] [Accepted: 09/24/2019] [Indexed: 11/16/2022]
Abstract
Lung toxicity is a serious concern during total body irradiation (TBI). Therefore, evaluation of accurate dose calculation when using lung blocks is of utmost importance. Existing clinical treatment planning systems can perform the calculation but there are large inaccuracies when calculating volumetric dose at extended distances in the presence of high atomic number materials. Percent depth dose and absolute dose measurements acquired at 400 cm SSD with a cerrobend block were compared with calculated values from the Eclipse treatment planning system using AAA and Acuros. The block was simulated in 2 ways; (1) manually drawing a contour to mimic the block and (2) creating a virtual block in the accessory tray. Although the relative dose distribution was accurately calculated, larger deviations of around 50% and 40% were observed between measured depth dose and absolute dose with AAA and Acuros, respectively. Deviations were reduced by optimizing the relative electron density in the contoured block or the transmission factor in the virtual block.
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van Leeuwen RG, Verwegen D, van Kollenburg PG, Swinkels M, van der Maazen RW. Early clinical experience with a total body irradiation technique using field-in-field beams and on-line image guidance. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2021; 16:12-17. [PMID: 33458337 PMCID: PMC7807619 DOI: 10.1016/j.phro.2020.09.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 08/23/2020] [Accepted: 09/21/2020] [Indexed: 01/28/2023]
Abstract
Background and purpose Total body irradiation (TBI) is a treatment used in the conditioning of patients prior to hematopoietic stem cell transplantation. We developed an extended-distance TBI technique using a conventional linac with multi-leaf collimator to deliver a homogeneous dose, and spare critical organs. Materials and methods Patients were treated either in lateral recumbent or in supine position depending on the dose level. A conventional linac was used with the patient midline at 350 cm from the beam source. A series of beams was prepared manually using a 3D treatment planning system (TPS) aiming to improve dose homogeneity, spare the organs at risk and facilitate accurate patient positioning. An optimized dose calculation model for extended-distance treatments was developed using phantom measurements. During treatment, in-vivo dosimetry was performed using electronic dosimeters, and accurate positioning was verified using a mobile megavoltage imager. We analyzed dose volume histogram parameters for 19 patients, and in-vivo measurements for 46 delivered treatment fractions. Results Optimization of the dose calculation model for TBI improved dose calculation by 2.1% at the beam axis, and 17% at the field edge. Treatment planning dose objectives and constraints were met for 16 of 19 patients. Results of in-vivo dosimetry were within the set limitations (±10%) with mean deviations of 3.7% posterior of the lungs and 0.6% for the abdomen. Conclusions We developed a TBI treatment technique using a conventional linac and TPS that can reliably be used in the conditioning regimen of patients prior to stem cell transplantation.
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Akino Y, Maruoka S, Yano K, Abe H, Isohashi F, Seo Y, Tamari K, Hirata T, Kawakami M, Nakae Y, Tanaka Y, Ogawa K. Commissioning of total body irradiation using plastic bead bags. JOURNAL OF RADIATION RESEARCH 2020; 61:959-968. [PMID: 32876686 PMCID: PMC7674696 DOI: 10.1093/jrr/rraa072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 04/11/2020] [Indexed: 06/11/2023]
Abstract
The goal of total body irradiation (TBI) is to deliver a dose to the whole body with uniformity within ±10%. The purpose of this study was to establish the technique of TBI using plastic bead bags. A lifting TBI bed, Model ORP-TBI-MN, was used. The space between the patient's body and the acrylic walls of the bed was filled with polyacetal bead bags. Patients were irradiated by a 10 MV photon beam with a source to mid-plane distance of 400 cm. The monitor unit (MU) was calculated by dose-per-MU, tissue-phantom-ratio and a spoiler factor measured in solid water using an ionization chamber. The phantom-scatter correction factor, off-center ratio and the effective density of the beads were also measured. Diode detectors were used for in vivo dosimetry (IVD). The effective density of the beads was 0.90 ± 0.09. The point doses calculated in an I'mRT phantom with and without heterogeneity material showed good agreement, with measurements within 3%. An end-to-end test was performed using a RANDO phantom. The mean ± SD (range) of the differences between the calculated and IVD-measured mid-plane doses was 1.1 ± 4.8% (-5.9 to 5.0%). The differences between the IVD-measured doses and the doses calculated with Acuros XB of the Eclipse treatment planning system (TPS) were within 5%. For two patients treated with this method, the differences between the calculated and IVD-measured doses were within ±6% when excluding the chest region. We have established the technique of TBI using plastic bead bags. The TPS may be useful to roughly estimate patient dose.
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Affiliation(s)
- Yuichi Akino
- Corresponding author. Oncology Center, Osaka University Hospital, 2-2 (D10), Yamadaoka, Suita, Osaka, 565-0871, Japan. Tel: (+81) 6-6879-3482; Fax: (+81) 6-6879-3489;
| | | | | | - Hiroshi Abe
- Nippon Life Hospital, Nishi-ku, Osaka 550-0006, Japan
| | - Fumiaki Isohashi
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Yuji Seo
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Keisuke Tamari
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Takero Hirata
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | | | - Yoshiki Nakae
- Nippon Life Hospital, Nishi-ku, Osaka 550-0006, Japan
| | - Yoshihiro Tanaka
- Department of Radiation Therapy, Japanese Red Cross Society Kyoto Daiichi Hospital, Kyoto 605-0981, Japan
| | - Kazuhiko Ogawa
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
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Cunha J, Santos W, Carvalho Júnior A. Conversion Coefficients of equivalent and effective doses in terms of air kerma for computational scenarios of Total Body Irradiation in lying-down patients. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2019.02.051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Pierce G, Balogh A, Frederick R, Gordon D, Yarschenko A, Hudson A. Extended SSD VMAT treatment for total body irradiation. J Appl Clin Med Phys 2018; 20:200-211. [PMID: 30592152 PMCID: PMC6333187 DOI: 10.1002/acm2.12519] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 11/09/2018] [Accepted: 11/13/2018] [Indexed: 12/17/2022] Open
Abstract
In this work, we develop a total body irradiation technique that utilizes arc delivery, a buildup spoiler, and inverse optimized multileaf collimator (MLC) motion to shield organs at risk. The current treatment beam model is verified to confirm its applicability at extended source‐to‐surface distance (SSD). The delivery involves 7–8 volumetric modulated arc therapy arcs delivered to the patient in the supine and prone positions. The patient is positioned at a 90° couch angle on a custom bed with a 1 cm acrylic spoiler to increase surface dose. Single‐step optimization using a patient CT scan provides enhanced dose homogeneity and limits organ at risk dose. Dosimetric data of 109 TBI patients treated with this technique is presented along with the clinical workflow. Treatment planning system (TPS) verification measurements were performed at an extended SSD of 175 cm. Measurements included: a 4‐point absolute depth‐dose curve, profiles at 1.5, 5, and 10 cm depth, absolute point‐dose measurements of an treatment field, 2D Gafchromic® films at four locations, and measurements of surface dose at multiple locations of a Alderson phantom. The results of the patient DVH parameters were: Body‐5 mm D98 95.3 ± 1.5%, Body‐5 mm D2 114.0 ± 3.6%, MLD 102.8 ± 2.1%. Differences between measured and calculated absolute depth‐dose values were all <2%. Profiles at extended SSD had a maximum point difference of 1.3%. Gamma pass rates of 2D films were greater than 90% at 5%/1 mm. Surface dose measurements with film confirmed surface dose values of >90% of the prescription dose. In conclusion, the inverse optimized delivery method presented in the paper has been used to deliver homogenous dose to over 100 patients. The method provides superior patient comfort utilizing a commercial TPS. In addition, the ability to easily shield organs at risk is available through the use of MLCs.
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Affiliation(s)
- Greg Pierce
- Department of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada.,Department of Physics & Astronomy, University of Calgary, Calgary, AB, Canada.,Department of Oncology, University of Calgary, Calgary, AB, Canada
| | - Alex Balogh
- Department of Oncology, University of Calgary, Calgary, AB, Canada.,Division of Radiation Oncology, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Rebecca Frederick
- Department of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada.,Department of Physics & Astronomy, University of Calgary, Calgary, AB, Canada
| | - Deborah Gordon
- Department of Radiation Therapy, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Adam Yarschenko
- Department of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Alana Hudson
- Department of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada.,Department of Oncology, University of Calgary, Calgary, AB, Canada
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