Abstract
3048
Purpose: 99mTc-Trodat-1 (TRODAT) imaging with a conventional dual-headed SPECT(C-SPECT) scanner has been routinely utilized to diagnose Parkinson’s disease (PD). However, the scan time usually requires 45-60 min, risking for subsequent patient motion. The CZT-SPECT scanner with higher system sensitivity may be feasible for TRODAT imaging benefited by reducing scan time.
Methods: This study enrolled 43 patients referred for clinically indicated TRODAT scan with C-SPECT equipped with fan-beam collimation. The clinical protocol routinely utilizes 45 min scan time at 3 h post TRODAT injection. Immediately patient were moved to a cardiac-dedicated CZT-SPECT scanner (NM530c) and imaged for 15 min after an optimal positing of striatal regions in the center of field-of-view. Images of C-SPECT were reconstructed with attenuation correction (AC) using the modified-Chang method while images of CZT-SPECT were reconstructed with OSEM with CT-based AC. Specific binding ratio (SBR) as (Astriatum - AOccipital)/ AOccipital in the striatum region was calculated for both C- and CZT-SPECT, and then compared.
Results: Among all patients, five of them were excluded due to difficult positioning in FOV center by enlarged head and shoulder sizes. In the rest of 38 patients, mean total counts in the striatum region were comparable (282,110±19,748 for C-SPECT and 321,446±25,715 for CZT-SPECT). Image truncation in the occipital region was normally observable in CZT-SPECT but not in C-SPECT. Linear correlation of left SBR between CZT- and C-SPECT was y (CZT-SPECT)= 1.0767x(C-SPECT), R2= 0.5541 and y (CZT-SPECT) = 1.5821x(C-SPECT), R2=0.6989 for right SBR. Conclusions: One-third time TRODAT SPECT imaging performed on a cardiac- dedicated CZT SPECT scanner might be feasible to measure the SBR. However, major challenges come from improper positioning and image truncation related to patients’ head and shoulder sizes.