Researchers report that circulating tumor DNA profiling can help select patients for radium-223 therapy in metastatic castration-resistant prostate cancer. The analysis, published in The Journal of Nuclear Medicine, describes a ctDNA-based approach intended to flag which patients are most likely to benefit from ^223Ra radiopharmaceutical treatment. The work reflects an expanding shift toward biomarker-driven radiopharmaceutical use—moving beyond blanket eligibility toward molecularly stratified therapy decisions in mCRPC, where treatment sequencing remains a challenge.