Radionuclide-Based Theranostic Mapping for Spatially Optimized Treatment Planning in Cervical Carcinoma.

Abstract

Background: Intratumoral heterogeneity in cervical carcinoma may influence absorbed dose distribution, treatment resistance, and response, but is not adequately captured by conventional uniform planning.

Methods: A total of 35 patients with histologically confirmed cervical carcinoma underwent baseline theranostic imaging. Voxel-wise tumor uptake was analyzed to derive SUV_max, SUV_mean, tumor-to-background ratio, coefficient of variation, entropy, and fractional low-, intermediate-, and high-uptake subregions. Voxel-based absorbed dose distributions were estimated, and a dose heterogeneity index was calculated. Conventional uniform planning was compared with theranostic-guided spatial optimization. An integrated theranostic score was developed for response prediction and risk stratification.

Results: Nonresponders showed higher uptake intensity, greater spatial heterogeneity, larger high-uptake fractions, and higher integrated theranostic scores than responders. Tumor absorbed dose exceeded that of bladder, rectum, and normal pelvic soft tissue. SUV_mean correlated positively with tumor absorbed dose, whereas uptake coefficient of variation correlated with dose heterogeneity. Theranostic-guided spatial optimization improved target coverage, conformity, and high-risk subregion coverage relative to conventional uniform planning. The integrated theranostic score demonstrated strong predictive performance for response classification (area under the receiver operating characteristic curve, 0.95; 95% confidence interval, 0.84-0.98).

Conclusions: Radionuclide theranostic mapping provided a quantitative framework linking spatial uptake heterogeneity to dosimetry, planning benefit, and treatment response in cervical carcinoma.