ESTRO 2024 - Abstract Book

S3469

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2024

fits were applied to population DRCs to model the data and compared with the Akaike information criterion (AIC).

Results:

Of 71 patients enrolled, 36 (51%) / 26 (37%) patients (SF = 12 / 8 patients and MF = 24 / 18 patients) from four centres were included in this study according to the availability of imaging datasets at the first [median (range) = 12.0 (11.1,15.2) months] / second [median (range) = 24.0 (23.2,25.2) months] time point. Ipsilateral kidney GFR decreased with respect to baseline at both time points (median GFR = -42% / -39% and -45% / -62% with respect to baseline at the first / second time point in the SF and MF cohort, p-values < 0.03). The ratio ipsilateral kidney V50% / Vtotal was correlated with the relative GFR change from baseline (r = 0.74 / 0.90 and 0.59 / 0.63 at the first / second time point in the SF and MF cohort, all p-values < 0.03). In the linearly decreasing region of population DRCs, renal function losses as compared with baseline were similar between the first / second time point in the SF cohort (renal function loss = 33.0±4.6% / 36.3±7.6% per 10 Gy of received dose) and MF cohort (renal function loss = 20.4±3.6% / 17.1±1.5% per 10 Gy of received dose). A logistic fit best modelled DRCs normalised to BED except for the MF cohort at the second time point (AIC logistic / exponential = 30 / 34 and 6 / 8 at the first time point and 34 /38 and 8 / 7 at the second time in the SF and MF cohort) [Fig. 2]. The DRCs converged to a plateau above the high-dose regions (> 100GyBED), where the renal function was 30% / 29% and 29% / 22% of the baseline value at the first / second time point in the SF and MF cohort.

Conclusion: