ESTRO 2024 - Abstract Book

S4065

Physics - Inter-fraction motion management and offline adaptive radiotherapy

ESTRO 2024

accumulated, respectively. For both approaches, the same reference plans and margins were used. Dose volume histograms (DVHs) with a bin width of 0.1 Gy were calculated for selected contours for accumulated plan dose analysis of IGRT and oa-MRgRT. Differences of the dose-volume histograms (DVH) comparing IGRT versus oa-MRgRT were analyzed using the Mann-Whitney U test. Selected dose volume points (DVP) used for clinical plan acceptance in our department were derived for both treatment approaches and compared across patients. For statistical analysis, the paired t-test was performed with a significance level of p<0.05.

Results:

Figure 1 illustrates the accumulated DVHs for the selected contours. In 50% of the patients, significant differences were observed for bladder, in 80% for penile bulb, in 20% for rectum, 60% of patients for trigonum, and for urethra membranacea. Figure 2 summarizes the differences of the selected DVPs between IGRT and oa-MRgRT. The DVP differences across the patients were found to be statistically significant for CTV D95% and Rectum Dmax with p=0.034 and p=0.000, respectively (cf. Figure 2 a and d).