Countermeasures against physical motion in schoolchildren requiring no sedation during rest and stress myocardial perfusion imaging with technetium-99m-tetrofosmin.

For children, cardiac nuclear medicine imaging has not been widely used because of problems of physical motion, even in schoolchildren who require no sedation. In this study, rest-stress myocardial perfusion imaging (MPI) with technetium-99m-tetrofosmin (Tc-99m TF) was performed with the use of a Vac-Loc cushion, a patient immobilizer commonly used for radiotherapy, for immobilizing school-age patients. The immobilizer attenuated the gamma radiation by 6%. By visual assessment, physical motion-related artifacts were markedly improved in images acquired with the immobilizer, compared to those without. In the assessment of image reproducibility with the immobilizer, taking the reproducibility as 2.5Σ + 0.7σ, there were deviations of 4.45, 5.28, and 3.28 mm along the X-, Y-, and Z-axes, respectively, demonstrating a high reproducibility and a negligible rest-stress position error. It is suggested that for radiotherapy, the immobilizer could expand the versatility of MPI while allowing only minimal physical motion in children.