Stress-first protocol for myocardial perfusion SPECT imaging with semiconductor cameras: high diagnostic performances with significant reduction in patient radiation doses

Abstract

When planned with a low-dose stress-first protocol on a CZT camera, MPI provides high diagnostic performances and a dramatic reduction in patient radiation doses. This reduction is even greater in low-risk subgroups with high rates of normal stress images, thus allowing the mean radiation dose to be balanced against cardiac risk in targeted populations.

CZT cameras: A technological jump for myocardial perfusion SPECT

“…This finding could lead to further reduce the injected activities. 11,16 In conclusion, the anthropomorphic phantom study of Zoccarato et al 4 yields definite evidence that the physical performances of these 2 CZT cameras are relatively similar, even if the corresponding images of the left ventricle are significantly different with a smaller wall thickness for the D.SPECT camera when using routine reconstruction parameters. These cameras are equipped with the same CZT material but operate with different collimation systems and reconstruction algorithms.…”

“…Thanks to the high sensitivities of CZT cameras, it has been possible to decrease recording times by a factor of 2 whereas the injected activities have decreased up to a factor of 3, leading to dramatic improvements in terms of patient tolerance and radiation doses. 11 This tomographic count sensitivity is currently being determined on reconstructed images from cardiac phantoms or from a punctual source according to the ratio of recording counts over actual activity. In patients, the actual left ventricular activities are unknown but may be replaced in the formula by the activities which are injected intravenously.…”

Which SPECT for today, which SPECT for tomorrow?

“…The rapidity of image acquisition can be traded (e.g., in younger patients) for reduced administered activity; 1 mSv studies are achievable and faster than ''normal'' imaging. 5,12 Full rest-stress studies are possible with 4.2-6.3 mSv and rapid imaging. 17 In reality, it is not only the administered activity from a single test which is of importance, but also the cumulative dose from multiple, repeat studies performed over decades to follow a chronic, noncurable disease.…”

“…With the combined adoption of ''stressfirst'' imaging, decreased time from tracer injection to imaging and with short image acquisition times, the 1 hour mark is within reach for CZT SPECT MPI. 12 Test time can be shortened even more using a very low Tl-201 stress dose (preferentially in older patients, [70 years of age), with immediate stress imaging and very short imaging time. This approach was proven with CZT cameras.…”

D-SPECT: New technology, old tricks

“…The D-SPECT takes this one step further by using an adjustable chair which also allows for semi-reclining prone scanning in addition to supine and semi-upright. 7 Allie et al provide some examples of breast and diaphragmatic attenuation artifacts which illustrates the benefits of patient repositioning. 6 Notably, the Discovery NM/CT 570c (GE Healthcare) camera has an integrated CT which provides an efficient platform for CT attenuation correction, coronary calcium scoring, or even CT coronary angiography in the same sitting.…”