P6C-3 Quantitative Ultrasonography Of Choroidal Melanoma Following Proton-Beam Radiotherapy

This prospective study was conducted on a cohort of 50 patients diagnosed with primary malignant melanoma to assess in vivo the ability of quantitative echography to detect changes in choroidal malignant melanomas after proton-beam irradiation. Echographic evaluations of these patients were performed at diagnosis and repeated every 6 months after treatment over a 2-year period. The acoustic parameters are derived from the calibrated tissue backscatter spectra (spectral slope, spectral intercept, and apparent integrated backscatter) of a selected tumor volume after correction of the apparatus transfer function and beam diffraction. Significant (p < 0.05) differences of spectral intercept and apparent integrated backscatter were observed between pre- and post-proton therapy, even when the tumor size after treatment was not significantly different from baseline. The results suggest that quantitative spectrum analysis of frequency-dependent backscatter can provide information about the structural modifications of choroidal malignant melanomas due to proton-beam.