A Mathematical Method for Determining Radiation Exposures Surrounding Technetium-99m-MDP Patients

Abstract

Radiation surveys of 16 technetium-99m- (^99mTc) MDP bone scintigram prostate cancer patients were obtained at 5 min, 4 hr, and 24 hr postadministration at survey distances of 1 ft (30.5 cm) and 3ft (~100 cm) from the patients. Patients with and without bone metastases were investigated. The data obtained were used to generate linear regression equations relating the radiation exposure between time periods as a function of body surface area (BSA). An example is provided where equation-generated radiation exposures for individuals are calculated around a hypothetical ^99mTc-MDP bone scan patient at various times and distances. Such equations can be used prospectively or retrospectively for estimating radiation exposures surrounding ^99mTc-MDP bone patients. The equations generated, which are applicable to the majority of all bone scan patients, approximate for the extremes of human morphology; a tall and slender or short and obese person. The relatively simple equations will be helpful for determining radiation exposures for a specific population of nuclear medicine patients.