Porównanie rozkładów dawek dla napromieniania mózgu dla technik dynamicznych IMRT i VMAT oraz techniki 3DCRT

Abstract

Whole-brain radiotherapy is a standard treatment for many brain metastases. Whole brain irradiation is a palliative treatment aimed at improving the patient's quality of life. Historically, this procedure was most often performed using two opposing side beams. However, as patients increasingly undergo repeated radiotherapy, dynamic techniques are used to minimize doses to critical organs. The study aimed to compare techniques used in whole brain irradiation in terms of dose analysis in critical organs (OAR, Organs at Risk). A group of 5 patients with brain metastases were qualified for the study. For each patient, a treatment plan was prepared using a static three-dimensional conformal radiotherapy technique (3DCRT) and two plans using a dynamic technique (IMRT, Intensity Modulated Radiation Therapy), and (VMAT, volumetric modulated arc therapy). All plans were compared with each other in terms of isodose coverage of 98% and 95% of the planned irradiation volume (PTV, Planning Target Volume) and the dose in 2% of the PTV volume, maximum doses in the OAR: lenses, eyes and in the left and right optic nerve. Mean maximum lens dose values ​​were below tolerance dose values but with better lens protection in favor of dynamic techniques; the average value of the maximum dose for the eyes and optic nerve was very similar consistent with the tolerance doses. Dynamic techniques enable better coverage of the PTV volume with the administered dose and minimize doses administered to critical organs.