ИСТИНА

Back­ground: Re­duc­tion the in­flu­ence of res­pi­ra­tion-in­duced in­trafrac­tional mo­tion of tis­sues is one of the main tasks of pro­ton ther­apy with a scan­ning beam. Re­paint­ing is one of the tech­niques of mo­tion com­pen­sa­tion. It con­sists in mul­ti­ple re­peated ir­ra­di­a­tions of the en­tire vol­ume or in­di­vid­ual iso-en­ergy lay­ers with a dose that is a mul­ti­ple of the pre­scribed dose. As a re­sult, the dose is av­er­aged, which leads to an in­crease in the uni­for­mity of the dose field. Pur­pose: Ex­per­i­men­tal sim­u­la­tion of vol­ume se­quen­tial re­paint­ing and dosi­met­ric es­ti­ma­tion of its ca­pa­bil­i­ties in the con­text of spot scan­ning pro­ton ther­apy (SSPT) using dy­namic phan­tom. Ma­te­ri­als and Meth­ods: Sim­u­la­tion of res­pi­ra­tion-like trans­la­tional mo­tion is per­formed using the non-an­thro­po­mor­phic water dy­namic phan­tom. Tar­get of this phan­tom is com­pat­i­ble with EBT-3 films. Es­ti­ma­tion of re­paint­ing tech­nique is based on the analy­sis of av­er­age dose, dose uni­for­mity in re­gion of in­ter­ests lo­cated within plan­ning tar­get vol­ume, and dose gra­di­ents. Re­sults: Re­paint­ing was es­ti­mated for mo­tion with am­pli­tudes of 2, 5, 10 mm with dif­fer­ent num­ber of it­er­a­tions up to 10 at the pre­scribed dose of 6 Gy. This one in­creased the uni­for­mity of the dose field from 85,9% to 96,0% at an am­pli­tude of 10 mm and 10 it­er­a­tions. Con­clu­sions: Vol­ume re­paint­ing im­proves the uni­for­mity of dose dis­tri­b­u­tion. How­ever, the ir­ra­di­a­tion time in­creases, and the dose gra­di­ents de­te­ri­o­rate in pro­por­tion to the am­pli­tude of mo­tion.