Prediction of tumor absorbed dose by Tc-99m-MDP scintigraphy prior to treatment with Sr-89.
A first order approximation of the tumor absorbed dose prior to treatment with Sr-89 was attempted in three patients treated for metastasized prostate carcinoma. All patients underwent bone scanning with Tc-99m-MDP two days before the administration of Sr-89, and a number of sequential quantitative images were obtained over the first 8 hours after Tc-99m-MDP injection. The collected data were used to derive an individualized Sr-89 time retention curve. Dosimetric estimations were subsequently based on the model described by ICRP Publ.30 (1979). In the present study a simplified model for the kinetics of both Sr-89 and Tc-99m-MDP was assumed. Normal adult data on the retention time of the two radiopharmaceuticals in the whole skeleton were combined and a linear relationship was derived between the time required for the same percentage uptake of the two radiopharmaceuticals after a single injection. The same relationship was assumed to hold for metastatic sites. The estimated absorbed dose in the principal metastases of the three patients, as well as normal bone of the same type and volume, is reported. A first order approximation of the absorbed dose by the skeleton is provided by the proposed method, before the therapeutic application of Sr-89 chloride using a diagnostic Tc-99m-MDP bone scan. The method is useful, simple, inexpensive and can be routinely performed.
Manetou
A
A
Medical Physics Unit, NIMTS Hospital Athens, Greece.
Limourls
G S
GS
D000042:Absorption; D000328:Adult; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000556:secondary*; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D008297:Male; D008954:Models, Biological; D009362:Neoplasm Metastasis; D011237:Predictive Value of Tests; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D011877:Radionuclide Imaging; D013324:Strontium / Q000493:pharmacokinetics / Q000627:therapeutic use*; D013669:Technetium Tc 99m Medronate / Q000493:pharmacokinetics; D014018:Tissue Distribution
D013669:Technetium Tc 99m Medronate; D013324:Strontium