potential effects of low-dose average ct on cardiac implantable electronic devices

Average ct has been shown to be more accurate than conventional helical ct in quantitation of the pet data. the risk of ct irradiation of a cardiac implantable electronic device (cied) causing an adverse event is low and is generally outweighed by the clinical benefit of a medically indicated examination. however, irradiation of cied over one breath cycle in cine ct scan for average ct could impose risks on a patient who is pacing dependent. the purpose of this study was to demonstrate that low-dose average ct can be safe for cied. a medtronic cied of model protecta vr was submerged in a saline bath for a series of 4-s cine ct scans on a ge ct scanner programmed to deliver a 2-cm-wide radiation at a dose rate of 0.9 to 41.2 mgy/s to the cied. the number of over-sensings was recorded as the interference of radiation to the cied. dose rates ≥ 1.9 mgy/s caused over-sensing. the higher the dose rate, the more over-sensings there were. the lowest dose rate of 0.9 mgy/s did not cause any over-sensing. low-dose average ct at 0.9 mgy/s can be safe for a cied patient who is pacing dependent.