Tomsk, Russian Federation
GRNTI 76.03 Медико-биологические дисциплины
GRNTI 76.33 Гигиена и эпидемиология
OKSO 14.04.02 Ядерные физика и технологии
OKSO 31.06.2001 Клиническая медицина
OKSO 31.08.08 Радиология
OKSO 32.08.12 Эпидемиология
BBK 51 Социальная гигиена и организация здравоохранения. Гигиена. Эпидемиология
BBK 534 Общая диагностика
TBK 5708 Гигиена и санитария. Эпидемиология. Медицинская экология
TBK 5712 Медицинская биология. Гистология
TBK 5734 Медицинская радиология и рентгенология
TBK 6212 Радиоактивные элементы и изотопы. Радиохимия
Purpose: To evaluate the methodological approaches to the prevention of radiation-induced complications after neutron-photon therapy considering the neutron-photon dose ratio in the tumor. Material and methods: The linear-quadratic model (LQM) and principles of neutron and photon dose distributions in a tissue-equivalent medium were used. Cases with the highest risk of radiation-induced complications (treatment by a single or two opposite fields) were discussed. The number of neutron-photon therapy sessions to ensure a combined total neutron and photon dose was determined where the RBE concept was used. When calculating the total effect (TE) and TDF factor characterizing the damage to the irradiated tissue, the effect of the radiation field size and subcutaneous fat layer on their values was taken into account. Results: Methods for selecting the ratio of the neutron and photon dose contribution to the total dose, providing the maximum permissible radiation dose, were developed. It was established that the dependences of TDF and TE factors and the differences in the values of the allowable number of photon therapy sessions on the depth of the tumor were less pronounced in cases with two opposite radiation fields compared to those with a single field. It can be explained by the fact that with increasing depth, an increase in the entrance dose is compensated by a decrease in the dose contribution formed during irradiation from the opposite field. Conclusion: For neutron-photon therapy using a linear-quadratic model, methodical approaches that might be used to provide an acceptable level of radiation-induced skin reactions for any ratio of neutron-photon doses in a tumor were proposed. The use of these techniques for planning neutron-photon therapy will minimize the risk of radiation-induced complications.
neutron therapy, TDF factor, linear quadratic model, early radiation-induced reactions
Введение
Нейтронную терапию (НТ) в онкологии рассматривают в качестве способа повышения эффективности лечения пациентов со злокачественными новообразованиями, резистентными к фотонному излучению [1, 2] и ее часто сочетают с фотонной терапией (ФТ) [3, 4]. При исследовании эффективности нейтронно-фотонной терапии (НФТ) изменяют соотношение суммарных доз нейтронов и фотонов в опухоли с целью определения оптимального вклада дозы нейтронов, соответствующего наибольшей степени поражения злокачественных клеток. При этом необходимо соблюсти такой баланс между дозами нейтронов и фотонов в опухоли, который обеспечит приемлемый риск частоты и выраженности лучевых реакций (ЛР) кожи.
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