How Useful is an Integrated SPECT/CT in Clinical Setting and Research?: Evaluation of a Low Radiation Dose 4 Slice System

Hybrid imaging is becoming a popular technology in nuclear medicine. We have evaluated the added value of an integrated SPECT/low-dose multislice CT over conventional planar/SPECT nuclear imaging. Phantom and clinical studies were performed on the InfiniaTM HawkeyeTM 4 slice (HWK-4) with an upgraded software package (Xeleris 2.05v) from GE Heatlthcare to assess 1) the benefit of CT for contrast-resolution, attenuation correction, and anatomic localisation; 2) the impact of hybrid imaging in 456 consecutive patients in a clinical setting. SPECT/CT data were compared to conventional planar/SPECT data and correlated to clinical, biochemical, morphological imaging, angiography, and pathology findings. SPECT/CT was well tolerated by the patients with minimal CT irradiation dose (< 2mSv). HWK-4 provided useful attenuation correction for its routine use in MPI and accurate anatomic localisation of physiological and pathological foci in 99m Tc-RBC, 99m Tc-HMPAO-WBC, 131/123 I-MIBG, Octreoscan ® , and 67 Ga studies. Low-dose multislice CT also helped detect gross morphological abnormalities. Hybrid imaging had a significant impact in ProstaScint ® and parathyroid imaging for image-guided intervention. In bone imaging and differentiated thyroid cancers, SPECT/CT was able to clarify equivocal findings from planar whole-body scan. SPECT/CT was also found useful to precisely localize sentinel lymph nodes. Research protocols are being evaluated for half-time acquisition with resolution recovery and quantification of tracer distribution. SPECT/low-dose multislice CT has been successfully implemented in routine clinical practice. CT provided added value for effective attenuation correction and accurate anatomic localisation of disease with an impact on patient management.