| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2002: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2001: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
Transmission computed tomography (TCT) with external radiation source was conventionally used for attenuation correction (AC). CT is recently used for AC instead of TCT. We evaluated the usefulness of TCT (TCT method) and CT (CT method) for the attenuation correction by a phantom and clinical study. In CT method, we also assessed the clinical usefulness of fused image (AC image with CT).
In TCT method, we used a 2-head gamma camera system equipped with asymmetric fan-beam collimator (GCA 7200, Toshiba) and the 3-head gamma camera equipped with fan-beam collimator (Prism 3000, Picker). We introduced a gantry-free gamma camera (SkyLight, ADAC) and multi-detector row CT (Lightspeed ultra, GE) in a same room as a CT/SPECT combined system. In CT method, we used this system.
In phantom study using a anthropomorphic phantom, both methods showed improvement in the uniformity of the distribution of Tl-201 in the myocardium. The contrast between the defect and normal myocardium was improved by the scatter correction.
In Tl-201 myocardial SPECT, there was the significant difference in specificity between non-corrected (NC) and AC images in the RCA territory and those in specificity and accuracy in the LCX territory. In the LAD territory, there were variable changes in sensitivity and specificity observed on between the AC images and the NC images.
Clinical usefulness of fused images was obtained in 84% (50/57) of cancer patients. Useful information on fused images was obtained in the diagnosis of staging and recurrence, differentiation of malignant from benign, and differentiation of pathological from physiological accumulation.
TCT method is useful for the attenuation correction on Tl-201 myocardial SPECT. Fused image made by CT method is useful for the nuclear studies of patients with cancer.
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