Quantitative Assessment of the Quality of Planning Total Irradiation of Children with Acute Lymphoblastic Leukemia

Purpose: To conduct a quantitative analysis of the quality of radiation planning for children with acute lymphoblastic and myeloblastic leukemia during total therapeutic irradiation. Assess dose loads on critical organs, assess the uniformity of dose distribution in the patient’s body. Material and methods: Total simultaneous irradiation of 39 patients (children) was carried out at a distance of 550 cm with two opposing fields on a Clinac iX electron accelerator with a nominal photon radiation energy of 6 MeV in a fixing mattress at the bottom with protective blocks for the lungs and a scattering plexiglass screen. The radiation dose per fraction was 2.0 Gy, total 12.0 Gy. Irradiation was carried out 2 times a day with an interval of 6 hours, in the morning and in the evening, with registration of the position of the protective blocks in relation to the lungs from the image. Number of fractions 6. The duration of irradiation was calculated using the Eclipse 3D planning system (Varian). Quantitative assessment of dose loads and homogeneity parameters was carried out using dosevolume histograms. Results: A quantitative analysis of plans for total therapeutic irradiation of 39 sick children with acute lymphoblastic leukemia was carried out. It has been shown that for 95 % of patients, doses in all organs are distributed evenly within a tolerance of 10 %; a similar picture is observed for a tolerance of 15 %. The dose homogeneity of the HI dose distribution within the target volume was assessed with and without boluses.In the presence of boluses, the average value of the homogeneity index HI for the entire group is on average 1.07 less than in the absence. And this is a positive result. Conclusion: The use of boluses increases the homogeneity of the dose distribution and is absolutely justified.