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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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Ngo N, Blomain ES, Simiele E, Romero I, Hoppe RT, Hiniker SM, Kovalchuk N. Improved organ sparing using auto-planned Stanford volumetric modulated arc therapy for total body irradiation technique. Pediatr Blood Cancer 2023; 70:e30589. [PMID: 37486149 DOI: 10.1002/pbc.30589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/07/2023] [Accepted: 07/08/2023] [Indexed: 07/25/2023]
Abstract
PURPOSE/OBJECTIVES To evaluate dosimetric differences between auto-planned volumetric modulated arc therapy (VMAT) total body irradiation (TBI) technique and two-dimensional radiotherapy using anterior-posterial/posterio-anterial beams (2D AP/PA) TBI technique. METHODS Ten pediatric patients treated with VMAT-TBI on Varian c-arm linac were included in this study. VMAT-TBI plans were generated using our in-house developed and publicly shared auto-planning scripts. For each VMAT-TBI plan, a 2D AP/PA plan was created replicating the institution's clinical setup with the patient positioned at extended source to skin distance (SSD) with a compensator to account for differences in patient thickness, 50% transmission daily lung blocks, and electron chest wall boosts prescribed to 50% of the photon prescription. Clinically relevant metrics were analyzed and compared between the VMAT and 2D plans. RESULTS All VMAT-TBI plans achieved planned target volume (PTV) D90% ≥ 100% of prescription. VMAT-TBI PTV D90% significantly increased (7.1% ± 2.9%, p < .001) compared to the 2D technique, whereas no differences were observed in global Dmax (p < .2) and PTV V110% (p < .4). Compared to the 2D plans, significant decreases in the Dmean to the lungs (-25.6% ± 11.5%, p < .001) and lungs-1 cm (-34.1% ± 10.1%, p < .001) were observed with the VMAT plans. The VMAT technique also enabled decrease of dose to other organs: kidneys Dmean (-32.5% ± 5.0%, p < .001) and lenses Dmax (-5.3% ± 8.1%, p = .03); and in addition, for 2 Gy prescription: testes/ovaries Dmean (-41.5% ± 11.5%, p < .001), brain Dmean (-22.6% ± 5.4%, p = .002), and thyroid Dmean (-18.2% ± 16.0%, p = .03). CONCLUSIONS Superior lung sparing with improved target coverage and similar global Dmax were observed with the VMAT plans as compared to 2D plans. In addition, VMAT-TBI plans provided greater dose reductions in gonads, kidneys, brain, thyroid, and lenses.
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Affiliation(s)
- Nicholas Ngo
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Erik S Blomain
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Eric Simiele
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Ignacio Romero
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Richard T Hoppe
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Susan M Hiniker
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
| | - Nataliya Kovalchuk
- Radiation Oncology Department, Stanford University Cancer Center, Palo Alto, California, USA
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Kovalchuk N, Simiele E, Skinner L, Yang Y, Howell N, Lewis J, Hui C, Blomain ES, Hoppe RT, Hiniker SM. The Stanford VMAT TBI Technique. Pract Radiat Oncol 2022; 12:245-258. [PMID: 35182803 DOI: 10.1016/j.prro.2021.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 11/17/2022]
Abstract
PURPOSE In this work, we describe the technical aspects of the XXX VMAT TBI technique, compare it to other VMAT TBI techniques, and share our initial experience. METHODS From September 2019 to August 2021, 35 patients were treated with VMAT TBI at our institution. Treatment planning was performed using in-house developed automated planning scripts. Organ sparing depended on the regimen: myeloablative (lungs, kidneys, and lenses); non-myeloablative with benign disease (lungs, kidneys, lenses, gonads, brain, and thyroid). Quality assurance was performed using EPID portal dosimetry and Mobius3D. Robustness was evaluated for the first ten patients by performing local and global isocenter shifts of 5 mm. Treatment was delivered using IGRT for every isocenter and every fraction. In-vivo measurements were performed on the matchline between the VMAT and AP/PA fields and on the testes for the first fraction. RESULTS The lungs, lungs-1cm, and kidneys Dmean were consistently spared to 57.6±4.4%, 40.7±5.5%, and 70.0±9.9% of the prescription dose, respectively. Gonadal sparing (Dmean=0.69±0.13 Gy) was performed for all patients with benign disease. The average PTV D1cc was 120.7±6.4% for all patients. The average Gamma passing rate for the VMAT plans was 98.1±1.6% (criteria of 3%/2mm). Minimal differences were observed between Mobius3D- and EclipseAAA-calculated PTV Dmean (0.0±0.3%) and lungs Dmean (-2.5±1.2%). Robustness evaluation showed that the PTV Dmax and lungs Dmean are insensitive to small positioning deviations between the VMAT isocenters (1.1±2.4% and 1.2±1.0%, respectively). The average matchline dose measurement indicated patient setup was reproducible (96.1±4.5% relative to prescription dose). Treatment time, including patient setup and beam-on, was 47.5±9.5 min. CONCLUSIONS The XXX VMAT TBI technique, from simulation to treatment delivery, was presented and compared to other VMAT TBI techniques. Together with publicly shared autoplanning scripts, our technique may provide the gateway for wider adaptation of this technology and the possibility of multi-institutional studies in the cooperative group setting.
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Affiliation(s)
- Nataliya Kovalchuk
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States
| | - Eric Simiele
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States
| | - Yong Yang
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States
| | - Nicole Howell
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States
| | - Jonathan Lewis
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States
| | - Caressa Hui
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States
| | - Erik S Blomain
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States
| | - Richard T Hoppe
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States
| | - Susan M Hiniker
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, United States.
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Uehara T, Monzen H, Tamura M, Inada M, Otsuka M, Doi H, Matsumoto K, Nishimura Y. Feasibility study of volumetric modulated arc therapy with Halcyon™ linac for total body irradiation. Radiat Oncol 2021; 16:236. [PMID: 34906180 PMCID: PMC8670260 DOI: 10.1186/s13014-021-01959-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/29/2021] [Indexed: 01/11/2023] Open
Abstract
Background The use of total body irradiation (TBI) with linac-based volumetric modulated arc therapy (VMAT) has been steadily increasing. Helical tomotherapy has been applied in TBI and total marrow irradiation to reduce the dose to critical organs, especially the lungs. However, the methodology of TBI with Halcyon™ linac remains unclear. This study aimed to evaluate whether VMAT with Halcyon™ linac can be clinically used for TBI. Methods VMAT planning with Halcyon™ linac was conducted using a whole-body computed tomography data set. The planning target volume (PTV) included the body cropped 3 mm from the source. A dose of 12 Gy in six fractions was prescribed for 50% of the PTV. The organs at risk (OARs) included the lens, lungs, kidneys, and testes. Results The PTV D98%, D95%, D50%, and D2% were 8.9 (74.2%), 10.1 (84.2%), 12.6 (105%), and 14.2 Gy (118%), respectively. The homogeneity index was 0.42. For OARs, the Dmean of the lungs, kidneys, lens, and testes were 9.6, 8.5, 8.9, and 4.4 Gy, respectively. The V12Gy of the lungs and kidneys were 4.5% and 0%, respectively. The Dmax of the testes was 5.8 Gy. Contouring took 1–2 h. Dose calculation and optimization was performed for 3–4 h. Quality assurance (QA) took 2–3 h. The treatment duration was 23 min. Conclusions A planning study of TBI with Halcyon™ to set up VMAT-TBI, dosimetric evaluation, and pretreatment QA, was established. Supplementary Information The online version contains supplementary material available at 10.1186/s13014-021-01959-3.
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Affiliation(s)
- Takuya Uehara
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan.
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Masakazu Otsuka
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
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Rassiah P, Esiashvili N, Olch AJ, Hua CH, Ulin K, Molineu A, Marcus K, Gopalakrishnan M, Pillai S, Kovalchuk N, Liu A, Niyazov G, Peñagarícano JA, Cheung F, Olson AC, Wu CC, Malhotra H, MacEwan IJ, Faught J, Breneman JC, Followill DS, FitzGerald TJ, Kalapurakal JA. Practice patterns of pediatric total body irradiation techniques: A Children's Oncology Group survey. Int J Radiat Oncol Biol Phys 2021; 111:1155-1164. [PMID: 34352289 DOI: 10.1016/j.ijrobp.2021.07.1715] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/30/2021] [Accepted: 07/28/2021] [Indexed: 12/25/2022]
Abstract
PURPOSE The aim of this study was to examine current practice patterns in pediatric total body irradiation (TBI) techniques among xxx member institutions. METHODS AND MATERIALS Between Nov 2019 and Feb 2020 a questionnaire, containing 52 questions related to the technical aspects of TBI was sent to medical physicists at 152 xxx institutions. The questions were designed to obtain technical information on commonly used TBI treatment techniques. Another set of 9 questions related to the clinical management of patients undergoing TBI was sent to 152 xxx member radiation oncologists at the same institutions. RESULTS Twelve institutions were excluded because TBI was not performed in their institutions. A total of 88 physicists from 88 institutions (63% response rate) and 96 radiation oncologists from 96 institutions responded (69% response rate). The AP/PA technique was the most common (49 institutions - 56%); 44 institutions (50%) used the lateral technique and 14 institutions (16%) used volumetric modulated arc therapy (VMAT)/Tomotherapy. Mid-plane dose rates of 6-15 cGy/min were most commonly used. The most common specification for lung dose was the mid lung dose for both AP/PA (71%) and lateral (63%) techniques. All physician responders agreed with the need to refine current TBI techniques and 79% supported the investigation of new TBI techniques to further lower the lung dose. CONCLUSION There is no consistency in the practice patterns, methods for dose measurement and reporting of TBI doses among xxx institutions. The lack of a standardization precludes meaningful correlation between TBI doses and clinical outcomes including disease control and normal tissue toxicity. The xxx radiation oncology discipline is currently undertaking several steps to standardize the practice and dose reporting of pediatric TBI using detailed questionnaires and phantom-based credentialing for all xxx centers.
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Affiliation(s)
- P Rassiah
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT.
| | - N Esiashvili
- Department of Radiation Oncology, Emory University, Atlanta, GA
| | - A J Olch
- Department of Radiation Oncology, University of Southern California and Children's Hospital of Los Angeles, Los Angeles, CA
| | - C H Hua
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - K Ulin
- Imaging and Radiation Oncology Core, Rhode Island QA Center, University of Massachusetts Medical School, Lincoln, RI
| | - A Molineu
- Imaging and Radiation Oncology Core, Houston QA Center, MD Anderson Cancer Center, Houston, TX
| | - K Marcus
- Department of Radiation Oncology, Harvard Medical School, Boston, MA
| | - M Gopalakrishnan
- Department of Radiation Oncology, Northwestern University, Chicago, IL
| | - S Pillai
- Department of Radiation Medicine, Oregon Health and Science University, Portland, OR
| | - N Kovalchuk
- Department of Radiation Oncology, Stanford University, Stanford, CA
| | - A Liu
- Department of Radiation Oncology, City of Hope, Los Angeles, CA
| | - G Niyazov
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - J A Peñagarícano
- Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
| | - F Cheung
- Medical Physics division, Princess Margaret Cancer Center, Toronto, Canada
| | - A C Olson
- Department of Radiation Oncology, Children's Hospital of Pittsburgh, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine Pittsburgh, PA
| | - C C Wu
- Department of Radiation Oncology, Columbia University Irving Medical Center, New York, NY
| | - H Malhotra
- Department of Radiation Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY
| | - I J MacEwan
- Department of Radiation Medicine and Applied Sciences, UC San Diego, La Jolla, CA
| | - J Faught
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - J C Breneman
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, OH
| | - D S Followill
- Imaging and Radiation Oncology Core, Houston QA Center, MD Anderson Cancer Center, Houston, TX
| | - T J FitzGerald
- Department of Radiation Oncology, University of Massachusetts, Worcester, MA
| | - J A Kalapurakal
- Department of Radiation Oncology, Northwestern University, Chicago, IL
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Simiele E, Skinner L, Yang Y, Blomain ES, Hoppe RT, Hiniker SM, Kovalchuk N. A Step Toward Making VMAT TBI More Prevalent: Automating the Treatment Planning Process. Pract Radiat Oncol 2021; 11:415-423. [PMID: 33711488 DOI: 10.1016/j.prro.2021.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/08/2021] [Accepted: 02/26/2021] [Indexed: 01/28/2023]
Abstract
PURPOSE Our purpose was to automate the treatment planning process for total body irradiation (TBI) with volumetric modulated arc therapy (VMAT). METHODS AND MATERIALS Two scripts were developed to facilitate autoplanning: the binary plug-in script automating the creation of optimization structures, plan generation, beam placement, and setting of the optimization constraints and the stand-alone executable performing successive optimizations. Ten patients previously treated in our clinic with VMAT TBI were used to evaluate the efficacy of the proposed autoplanning process. Paired t tests were used to compare the dosimetric indices of the produced auto plans to the manually generated clinical plans. In addition, 3 physicians were asked to evaluate the manual and autoplans for each patient in a blinded retrospective review. RESULTS No significant differences were observed between the manual and autoplan global Dmax (P < .893), planning target volume V110% (P < .734), kidneys Dmean (P < .351), and bowel Dmax (P < .473). Significant decreases in the Dmean to the lungs and lungs-1cm (ie, lungs with 1-cm inner margin) volumes of 5.4% ± 6.4% (P < .024) and 6.8% ± 7.4% (P < .017), respectively, were obtained with the autoplans compared with the manual plans. The autoplans were selected 77% of the time by the reviewing physicians as equivalent or superior to the manual plans. The required time for treatment planning was estimated to be 2 to 3 days for the manual plans compared with approximately 3 to 5 hours for the autoplans. CONCLUSIONS Large reductions in planning time without sacrificing plan quality were obtained using the developed autoplanning process compared with manual planning, thus reducing the required effort of the treatment planning team. Superior lung sparing with the same target coverage and similar global Dmax were observed with the autoplans as compared with the manual treatment plans. The developed scripts have been made open-source to improve access to VMAT TBI at other institutions and clinics.
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Affiliation(s)
- E Simiele
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - L Skinner
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Y Yang
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - E S Blomain
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - R T Hoppe
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - S M Hiniker
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - N Kovalchuk
- Department of Radiation Oncology, Stanford University, Stanford, California.
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Blomain ES, Kovalchuk N, Neilsen BK, Skinner L, Hoppe RT, Hiniker SM. A Preliminary Report of Gonadal-Sparing TBI Using a VMAT Technique. Pract Radiat Oncol 2020; 11:e134-e138. [PMID: 32795616 DOI: 10.1016/j.prro.2020.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/19/2020] [Accepted: 07/24/2020] [Indexed: 01/28/2023]
Abstract
Reproductive toxicity is common after total body irradiation (TBI) and has major quality of life implications for patients. In that context, this is the first report of gonadal-sparing volumetric-modulated arc therapy (VMAT) TBI, successfully delivered in a boy and a girl with aplastic anemia. Both patients' VMAT TBI plans demonstrated improved gonadal sparing versus simulated conventional 2-dimensional (2D) approach (mean testes dose, 0.45 Gy VMAT vs 0.72 Gy 2D; mean ovary dose, 0.64 Gy VMAT vs 1.47 Gy 2D). Planning target volume coverage was also improved for both cases with the VMAT plan versus conventional 2D plan (2 Gy D90% vs 1.9 Gy D90%, respectively). Given these dosimetric advantages, the present study can serve as a proof-of-concept for further prospective studies evaluating this technique for wider applications in populations receiving TBI.
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Affiliation(s)
- Erik S Blomain
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Nataliya Kovalchuk
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Beth K Neilsen
- College of Medicine, University of Nebraska, Omaha, Nebraska
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Richard T Hoppe
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Susan M Hiniker
- Department of Radiation Oncology, Stanford University, Stanford, California.
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Symons K, Morrison C, Parry J, Woodings S, Zissiadis Y. Volumetric modulated arc therapy for total body irradiation: A feasibility study using Pinnacle 3 treatment planning system and Elekta Agility™ linac. J Appl Clin Med Phys 2018; 19:103-110. [PMID: 29368389 PMCID: PMC5849856 DOI: 10.1002/acm2.12257] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 11/06/2017] [Accepted: 12/05/2017] [Indexed: 12/11/2022] Open
Abstract
A study was undertaken to explore the use of volumetric modulated arc therapy (VMAT) for total body irradiation (TBI). Five patient plans were created in Pinnacle3 using nine 6 MV photon dynamic arcs. A dose of 12 Gy in six fractions was prescribed. The planning target volume (PTV) was split into four subsections for the head, chest, abdomen, and pelvis. The head and chest beams were optimized together, followed by the abdomen and pelvis beams. The last stage of the planning process involved turning all beams on and performing a final optimization to achieve a clinically acceptable plan. Beam isocenters were shifted by 3 or 5 mm in the left-right, anterior-posterior, and superior-inferior directions to simulate the effect of setup errors on the dose distribution. Treatment plan verification consisted of ArcCheck measurements compared to calculated doses using a global 3%/3 mm gamma analysis. All five patient plans achieved the planning aim of delivering 12 Gy to at least 90% of the target. The mean dose in the PTV was 12.7 Gy. Mean lung dose was restricted to 8 Gy, and a dose reduction of up to 40% for organs such as the liver and kidneys proved feasible. The VMAT technique was found to be sensitive to patient setup errors particularly in the superior-inferior direction. The dose predicted by the planning system agreed with measured doses and had an average pass rate of 99.2% for all arcs. VMAT was found to be a viable treatment technique for total body irradiation.
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Affiliation(s)
- Kirsty Symons
- Genesis Cancer Care WADepartment of Radiation OncologyFiona Stanley HospitalMurdochWAAustralia
| | - Colm Morrison
- Genesis Cancer Care WADepartment of Radiation OncologyFiona Stanley HospitalMurdochWAAustralia
- School of PhysicsThe University of Western AustraliaPerthWAAustralia
| | - Jason Parry
- Genesis Cancer Care WADepartment of Radiation OncologyFiona Stanley HospitalMurdochWAAustralia
| | - Simon Woodings
- Genesis Cancer Care WADepartment of Radiation OncologyFiona Stanley HospitalMurdochWAAustralia
- Department of RadiotherapyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Yvonne Zissiadis
- Genesis Cancer Care WADepartment of Radiation OncologyFiona Stanley HospitalMurdochWAAustralia
- School of SurgeryThe University of Western AustraliaPerthWAAustralia
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Morrison CT, Symons KL, Woodings SJ, House MJ. Verification of junction dose between VMAT arcs of total body irradiation using a Sun Nuclear ArcCHECK phantom. J Appl Clin Med Phys 2017; 18:177-182. [PMID: 29082594 PMCID: PMC5689932 DOI: 10.1002/acm2.12208] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/09/2017] [Accepted: 09/11/2017] [Indexed: 11/06/2022] Open
Abstract
A volumetric modulated arc therapy (VMAT) approach to total body irradiation (TBI) has recently been introduced at our institution. The planning target volume (PTV) is divided into separate sub-volumes, each being treated with 2 arcs with their own isocentre. Pre-treatment quality assurance of beams is performed on a Sun Nuclear ArcCHECK diode array. Measurement of junction regions between VMAT arcs with separate isocentres has previously been performed with point dose ionization chamber measurements, or with films. Translations of the ArcCHECK with respect to a known distance between the adjacent isocentres of two arcs, which are repeated with the ArcCHECK in an inverted position, allows the recording of a junction dose map. A 3%/3 mm global gamma analysis (10% threshold) pass rate for arc junctions were comparable to their component arcs. Dose maps of junction regions between adjacent arcs with different isocentres can be readily measured on a Sun Nuclear ArcCHECK diode array.
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Affiliation(s)
- Colm T Morrison
- Department of Radiation Oncology, Genesis Cancer Care WA, Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch, 6150, Western Australia.,School of Physics, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, Western Australia
| | - Kirsty L Symons
- Department of Radiation Oncology, Genesis Cancer Care WA, Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch, 6150, Western Australia
| | - Simon J Woodings
- Department of Radiation Oncology, Genesis Cancer Care WA, Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch, 6150, Western Australia.,School of Physics, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, Western Australia
| | - Michael J House
- School of Physics, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, Western Australia
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