Attenuation correction is very important for quantitative SPECT imaging. We designed an uncollimated non-uniform line array source (non-uniform LAS) for attenuation correction based on transmission computed tomography (TCT) using Tc-99m and compared its performance with an uncollimated uniform line array source (uniform LAS) in a thorax phantom study. This non-uniform LAS was attached to one ca...

Localization of 99mTc- hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) by parathyroid adenomas is well known, and this warrants MIBI scan to evaluate suspected parathyroid adenoma in primary hyperparathyroidism. Typically, the radionuclide concentrates in both the thyroid gland and parathyroid adenoma in early images, and later on delayed images washes out slowly from the...

Molecular imaging technique is an attractive tool to detect liver disease at early stage. This study aims to develop a simultaneous dual-isotope single photon emission computed tomography (SPECT)/CT imaging method to assist diagnosis of hepatic tumor and liver fibrosis. Animal models of liver fibrosis and orthotopic human hepatocellular carcinoma (HCC) were established. The tracers of (131)I-NG...

We report a case of intrathyroidal and ectopic parathyroid hyperplasia in a 47-year-old female patient with secondary hyperparathyroidism. During evaluation for end stage renal disease, hypercalcemia and hyperparathyroidism were detected in laboratory exam and thyroid nodules were found in computed tomography, and thyroid ultrasonography. In subsequent dual-phase technetium-99m methoxyisobutrli...

Simultaneous imaging of Tc-99m and I-123 would have a high clinical potential in the assessment of brain perfusion (Tc-99m) and neurotransmission (I-123) but is hindered by cross-talk between the two radionuclides. Monte Carlo simulations of 15 different dual-isotope studies were performed using a digital brain phantom. Several physiologic Tc-99m and I-123 uptake patterns were modeled in the br...

Background: The advantages of proton beam in radiation therapy- like small lateral scattering as well as absence of exit dose tail in the organs which are after the tumor- make it capable of delivering more treatment doses to the target and much lesser to the critical tissues near it. Materials and Methods: In this study, the Monte Carlo MCNPX code has been used to simulate a slab head phantom ...

Following administration of 2.5-5.0 mCi f 9mTc]pertechnetate, several hundred microcuries may be present in the necks of hyperthyroid patients after 6 hr. Coincidence summing of Tc-99m photons may disturb 1-131 uptake measurements in such patients if an oral diagnostic dose of 1-131 is administered immediately after completion of a f 9mTc]pertechnetate scintigram. Using a lower discriminator le...

OBJECTIVES The energy resolution of a cadmium-zinc-telluride (CZT) solid-state semiconductor detector is about 5%, and is superior to the resolution of the conventional Anger type detector which is 10%. Also, the window width of the high-energy part and of the low-energy part of a photo peak window can be changed separately. In this study, we used a semiconductor detector and examined the effec...

PURPOSE A phantom study was conducted to evaluate the feasibility of body contour definition with Compton scatter photons from external sources of technetium-99m pertechnetate (Tc-99m) to create a fusion image of CT and SPECT images. METHODS External sources of 1 mCi (37 MBq) Tc-99m were placed on each collimator, and body-contour SPECT images were obtained with an energy window of 100 keV +/...