Russian Federation
employee
Russian Federation
employee
Russian Federation
GRNTI 29.05 Физика элементарных частиц. Теория полей. Физика высоких энергий
Purpose: Combination of total body irradiation (TBI) with chemotherapy is widely used technique for conditioning before hematopoietic stem cell transplantation for patient with hematological malignancies worldwide. Total body irradiation for patients with high height has to be divided into two parts: irradiation of upper part of the patient’s body (including head, body and part of legs) and irradiation of lower part of the patient’s body (including leg). There is an area in which the fields overlap each other – the junction area. The aim of this work is the development and verification of simple junction technique that would provide the dose distribution in the junction area from 90 to 125 % of prescribed dose. Material and methods: Total body irradiation was performed on the Tomotherapy machine using helical geometry of the beam delivery. Distribution of the dose in junction area was investigated. Simple solution was proposed: during the optimization of the radiotherapy plan certain margin should be maintained between upper and lower targets while dose distribution in junction area satisfies the uniformity requirements for the given irradiation geometry. The dimension of the margin was determined experimentally using a CheesePhantom and radiochromic EBT-2 films. The uniformity of dose distribution in the junction area was monitored by in vivo measurements using radiochromic EBT-2 films located on the skin surface of patients. Results: The dimension of the margin at which the dose in the junction area is within the range of 90 to 125 % of the prescribed dose was determined experimentally and amounted to 5.25 cm. The values of the measured dose were in the range from 97 to 105 %. In total 18 in vivo measurements of the junction area were performed. According to the results of in vivo dosimetry, the values of the doses measured in the junction area were in the range from 93 ± 3 % to 108 ± 4 %. Conclusion:The developed planning method with the selected plan geometry ensures satisfactory heterogeneity of the dose distribution in the area of field junction between the upper and lower irradiation regions, despite of the existing uncertainty of patient positioning. Results were confirmed by in vivo measurements. The obtained data can be used for total body irradiation of the patients using Helical Tomotherapy.
radiotherapy, tomotherapy, total body irradiation, junction area
Тотальное облучение тела (ТОТ) – это облучение всего тела человека. При этом требуется снижение дозы на критические органы (легкие, почки и др.). В сочетании с химиотерапией ТОТ широко используется у пациентов с гемобластозами перед трансплантацией гемопоэтических стволовых клеток. Основная цель ТОТ заключается в элиминации опухолевых клеток и иммуносупрессии. Традиционно используется облучение в СОД 12 Гр за 6 фракций.
1. Halperin EC, Brady LW, Perez CA, et al. Total body and hemibody irradiation. Perez and Brady’s principles and practice of radiation oncology. New York. Lippincott Williams & Wilkins. 2007:364-377.
2. Hui SK, Kapatoes J, Fowler J, Henderson D, et al. Feasibility study of helical tomotherapy for total body or total marrow irradiation. Medical Physics. 2005;32(10):3214-3224. DOI:https://doi.org/10.1118/1.2044428.
3. Peñagarícano JA, Chao M, Van Rhee F, et al. Clinical feasibility of TBI with helical tomotherapy. Bone Marrow Transplant. 2011;46(7):929-935. DOIhttps://doi.org/10.1038/bmt.2010.237.
4. Gruen A, Ebell W, Wlodarczyk W, et al. Total Body Irradiation (TBI) using Helical Tomotherapy in children and young adults undergoing stem cell transplantation. BioMed Central Radiation Oncology. 2013;8:92. DOI:https://doi.org/10.1186/1748-717X-8-92.
5. Wong JY, Rosenthal J, Liu A, Schultheiss T, et al. Image-guided total-marrow irradiation using helical Tomotherapy in patients with multiple myeloma and acute leukemia undergoing hematopoietic cell transplantation. Int. J. Radiation Oncology Biol. Phys. 2009;73(1):273-279. DOI:https://doi.org/10.1016/j.ijrobp.2008.04.071.
6. Kobyzeva DA, Maschyan MA, Willich NA, et al. The first Russian experience of TomoTherapy for total body irradiation in children. Russian Journal of Pediatric Hematology and Oncology. 2016;3(2):64-67. DOI:https://doi.org/10.17650/2311-1267-2016-3-2-64-67. (In Russ.).
7. Corvò R, Zeverino M, Vagge S, et al. Helical tomotherapy targeting total bone marrow after total body irradiation for patients with relapsed acute leukemia undergoing an allogeneic stem cell transplant. Radiotherapy and Oncology. 2011;98(3):382-386. DOI:https://doi.org/10.1016/j.radonc.2011.01.016.
8. Zeverino M, Agostinelli S, Taccini G, et al. Advances in the implementation of helical tomotherapy-based total marrow irradiation with a novel field junction technique. Medical Dosimetry. 2012;37(3):314-320. DOI:https://doi.org/10.1016/j.meddos.2011.12.001.
9. Mancosu P, Navarria P, Castagna L, et al. Plan robustness in field junction region from arcs with differentpatient orientation in total marrow irradiation with VMAT. Physica Medica. 2015;31(7):677-682. DOI:https://doi.org/10.1016/j.ejmp.2015.05.012.
10. Sun R, Cuenca X, Itti R, et al. First French experience of total body irradiation using helical Tomotherapy. Cancer Radiotherapie. 2017;21(5):365-372. DOI:https://doi.org/10.1016/j.canrad.2017.01.014.
11. Langen K, Papanikolaou N, Balog J, et al. QA for helical tomotherapy: Report of the AAPM Task Group 148. Medical Physics. 2010;37(9):4817-4853. DOI:https://doi.org/10.1118/1.3462971.
12. Tomo Planning Guide 107272A. TomoTherapy® Treatment System. 2012.
13. Micke A, Lewis DF, Yu X. Multichannel film dosimetry with nonuniformity correction. Medical Physics. 2011;38(5):2523-2534. DOI:https://doi.org/10.1118/1.3576105.
14. Aland T, Kairn T, Kenny J. Evaluation of a Gafchromic EBT2 film dosimetry system for radiotherapy quality assurance. Australasian Physical & Engineering Sciences in Medicine. 2011;34(2):251-260. DOI:https://doi.org/10.1007/s13246-011-0072-6.
15. Kissick MW, Fenwick J, James JA, et al. The helical tomotherapy thread effect. Medical Physics. 2005;32(5):1414-1423. DOI:https://doi.org/10.1118/1.1896453.
