Patient effective radiation dose and associated risk from transmission scans using 153Gd line sources in cardiac spect studies.

The aim of the present study was to determine the contribution of transmission measurements acquisition to total patient effective dose from cardiac SPECT studies. A dual-head L-shaped gamma camera equipped with a transmission scan acquisition system based on two 153Gd line sources was used to simulate transmission measurements acquisition exposure on an anthropomorphic phantom. Thermoluminescence dosimeters were used to directly monitor the dose to 550 measuring points in the phantom. The effective dose and associated risk from transmission scans acquisition were estimated and compared to those associated to the radiopharmaceutical injected. The maximum effective dose from a typical transmission measurements acquisition was 1.3 microSv and 1.9 microSv for male and female patients, respectively. The contribution of the typical transmission scans acquisition to total patient radiation risk from a cardiac SPECT study is less than 10(-3). Thus, radiation exposure may not be considered as a limiting factor for the clinical application of attenuation correction methods based on transmission measurements in cardiac SPECT.