The radiation dose to overweighted patients undergoing myocardial perfusion SPECT can be significantly reduced : validation of a linear weight-adjusted activity administration protocol

Background: Large body size can cause a higher proportion of emitted photons being attenuated within the patient. Therefore, clinical myocardial perfusion SPECT (MPS) protocols often include unproportionally higher radioisotope activity to obese patients. The aim was to evaluate if a linear weight-adjusted low-dose protocol can be applied to obese patients and thereby decrease radiation exposure. Methods and result: Two hundred patients (>110 kg, BMI 18-41, [n = 69], ≤ 110 kg, BMI 31-58, [n = 131]) underwent 99mTc-tetrofosmin stress examination on a Cadmium Zinc Telluride or a conventional gamma camera using new generations of reconstruction algorithm (Resolution Recovery). Patients 120 kg received 570 MBq according to clinical routine. Patients >110 kg had 130% total number of counts in the images compared to patients