Does absorbed dose predict outcome in radionuclide therapy
In plain words
In external beam treatment, more dose means more tumour control. Whether the same holds for radioactive drugs, where dose arrives slowly and unevenly, has not been shown convincingly.
Precise statement
Establish whether tumour absorbed dose, computed from quantitative imaging and time-activity integration for Lu-177 labelled agents, predicts response with a slope distinguishable from zero, and whether kidney and marrow absorbed dose predicts toxicity. Typical delivered tumour doses span $10^3$ to $3 x 10^4\,\mathrm{rad}$ at dose rates of 1 to 100 rad/h. An answer is a dose-response relation with confidence intervals, or a demonstration that dose rate and biological factors dominate.
What would settle it
Prospective trials randomizing or stratifying by measured absorbed dose rather than administered activity.
Status in the literature
Unverified note
Dosimetry-guided dose escalation studies reported through 2024 support a relation for some agents; fixed-activity dosing remains standard practice.