• 대한핵의학회지
• /
• 제33권3호
• /
• pp.337-340
• /
• 1999

Thallium-201 brain SPECT is utilized in the diagnosis of brain tumor especially in cases where CT or MRI findings alone cannot differentiate malignant lesion from benign. Recently we came across two cases of positive T1-201 brain SPECT in clinically suspected brain tumor patients that turned out to be hemorrhagic cerebral infarction instead on biopsy. The findings in these cases demonstrate that thallium-201 accumulation may occur by the breakdown of the blood-brain barrier and phagocytic cell infiltration in the liquefaction stage of infarction.

• Journal of Chest Surgery
• /
• 제47권5호
• /
• pp.465-467
• /
• 2014

We present a patient who developed recurrent angina after coronary artery bypass grafting (CABG). Myocardial single-photon emission computed tomography (SPECT) demonstrated deterioration in the myocardial perfusion, and coronary angiography revealed an overgrown side branch of the grafted left internal thoracic artery (ITA); otherwise, there were no significant changes compared with previous imaging studies obtained after the CABG. After percutaneous embolization of the grafted left ITA side branch, the angina was resolved and myocardial SPECT showed improved perfusion.

• 대한방사선기술학회지:방사선기술과학
• /
• 제19권1호
• /
• pp.89-94
• /
• 1996

Misalignment between the electronic and mechanical axes of rotation will result in artifact generation and image degradation during single photon emission computed tomography(SPECT) reconstruction. Acceptance and quality control testing procedures have not emphasized the variability in center of rotation(COR) measurements caused by collimators and the need to verify uniformity across the full collimator field of view (FOV). Variation from the mean COR across the FOV was tested in four different collimators using multiple point source acquisitions. The mean COR was different for each collimator and one of the four had a > 0.5 pixel difference from the mean COR on some area of the FOV, This variation makes this collimator unacceptable for SPECT acquisition. Thus, initial acceptance testing of SPECT collimators should verify a uniform COR across the full FOV and collimators with a variability from the mean COR > 0.5 pixels should be rejected.

• Journal of Chest Surgery
• /
• 제45권4호
• /
• pp.251-253
• /
• 2012

We report a redo coronary artery bypass grafting (CABG) in a 55-year-old man. Angina recurred 7 years after the initial surgery. Coronary angiography showed all patent grafts except a faint visualization of the in situ right gastroepiploic artery (RGEA) graft, which was anastomosed to the posterior descending coronary artery, associated with celiac axis stenosis. Redo-CABG was performed at postoperative 10 years because of aggravated angina and decreased perfusion of the inferior wall in the myocardial single photon emission computed tomography. The saphenous vein graft was interposed between the 2 in situ grafts used previously; the right internal thoracic artery and RGEA grafts. Angina was relieved and myocardial perfusion was improved.

• 대한한방내과학회지
• /
• 제22권3호
• /
• pp.437-442
• /
• 2001

For ischemic cerebrovascular disease, it is well known that early luxury perfusion is related to a good clinical outcome and single photon emission computed tomography(SPECT) has the potential for providing useful information about regional cerebral blood flow. We report one case of Rt. MCA infarction mainly treated by oriental medicine and revealed luxury perfusion without thrombolysis. In acute stage, neurological deficits of the patient were very severe. 99mTc-HMPAO SPECT images obtained 10days after the attack showed large perfusion defect in the Rt. MCA territory. We followed up 99mTc-HMPAO SPECT 40days after the ictus. Despite of the poor early perfusion, we found considerably improved perfusion and neurological improvement.

• 방사선산업학회지
• /
• 제6권3호
• /
• pp.245-249
• /
• 2012

Demand of fluid flow visualization has increased in industrial processes, because medical imaging technology is highly developed. As a part of the industrial process imaging technology, industrial single photon emission computed tomography (SPECT) system was developed to measure the cross-sectional distribution of the process fluid. The SPECT consists of 36 NaI (Tl) detectors with the hexagonal configuration. Reconstructed images were acquired for various positions of radioactive source to estimate SPECT device performance. To evaluate the reliability of the experimental results, the Monte Carlo simulation results are compared with experimental results. In general, the experimental and simulation results were consistent. However, as the source position was getting far from the center of the reactor, the accuracy of reconstructed images was compromised. It seems to be due to the inconsistent spatial resolution of the collimators according to the source position.

• 방사선산업학회지
• /
• 제8권1호
• /
• pp.23-27
• /
• 2014

Industrial single photon emission computed tomography (SPECT) is an useful technique to investigate the dynamic behavior of process flow. In the present study, to evaluate the influence of a void on the performance of industrial SPECT, industrial SPECT with various radioisotope sources and gas holdups was modeled by the Monte Carlo simulation. The results are very encouraging; that is, the void little influences the performance of industrial SPECT, which means that industrial SPECT could be a suitable tool to investigate the dynamic characteristics of the flow in a water-air phase process.

• 핵의학기술
• /
• 제28권1호
• /
• pp.1-11
• /
• 2024

Hypoxia, defined as the deficiency of oxygen, is a significant hallmark of cancers presenting in the majority of solid tumors. Detection of tumor hypoxia is essential in cancer diagnosis to prevent cancer progression, metastasis, and resistance to cancer therapies in clinical practices. Single-photon emission computed tomography (SPECT) is one of the methods studied and applied for hypoxia detection with the use of radiolabeled imaging agents in which ^99mTc is the common radioisotope used for radiolabeling. Nitroimidazoles are the hypoxia-targeting moieties presenting in numerous ^99mTc-radiolabeled imaging agents due to their bio-reducible ability in hypoxic environments. Recently, in addition to ^99mTc-labeled radiopharmaceuticals containing one nitroimidazole unit, there has been considerable attention given to ^99mTc-radiopharmaceuticals bearing two or more nitroimidazole units. This review summarizes the synthesis of hypoxia-targeting chelators and radiolabeling processes to produce these ^99mTc-radiopharmaceuticals for SPECT imaging.

• Korean Journal of Radiology
• /
• 제24권10호
• /
• pp.1017-1027
• /
• 2023

Objective: The assessment of cortical integrity following renal injuries with planar Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy depends on measuring relatively decreased cortical uptake (i.e., split renal function [SRF]). We analyzed the additive values of the volumetric and quantitative analyses of the residual cortical integrity using single-photon emission computed tomography (SPECT) compared to the planar scintigraphy. Materials and Methods: This prospective study included 47 patients (male:female, 32:15; age, 47 ± 22 years) who had non-operatively managed renal injuries and underwent DMSA planar and SPECT imaging 3-6 months after the index injury. In addition to planar SRF, SPECT SRF, cortical volume, and absolute cortical uptake were measured for the injured kidney and both kidneys together. The correlations of planar SRF with SPECT SRF and those of SRF with volumetric/quantitative parameters obtained with SPECT were analyzed. The association of SPECT parameters with renal function, grades of renal injuries, and the risk of renal failure was also analyzed. Results: SPECT SRF was significantly lower than planar SRF, with particularly higher biases in severe renal injuries. Planar and SPECT SRF (dichotomized with a cutoff of 45%) showed 19%-36% of discrepancies with volumetric and quantitative DMSA indices (when dichotomized as either high or low). Absolute cortical uptake of the injured kidney best correlated with glomerular filtration rate (GFR) at follow-up (ρ = 0.687, P < 0.001) with significant stepwise decreases by GFR strata (90 and 60 mL/min/1.73 m²). Total renal cortical uptake was significantly lower in patients with moderate-to-high risk of renal failure than those with low risk. However, SRF did not reflect GFR decrease below 60 mL/min/1.73 m² or the risk of renal failure, regardless of planar or SPECT (count- or volume-based SRF) imaging. Conclusion: Quantitative measurements of renal cortical integrity assessed with DMSA SPECT can provide more clinically relevant and comprehensive information than planar imaging or SRF alone.

• 대한핵의학회지
• /
• 제39권2호
• /
• pp.94-99
• /
• 2005

Electrocardiogram-gated single photon omission computed tomography (SPECT) provides valuable information in the assessment of both myocardial perfusion and ventricular function. Tl-201 is a suboptimal isotope for gating. Tl-201 images are more blurred compared with Tc-99m tracers due to the increased amount of scattered photons and use of a smooth filter. The average myocardial count densities are approximately one-half those of conventional technetium tracers. However, Tl-201 is still widely used because of its well-established utility for assessing myocardial perfusion, viability and risk stratification. Gated SPECT with Tl-201 enables us to assess both post-stress and rest left ventricular volume and function. Previous studies with gated Tl-201 SPECT measurements of ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) have shown high correlation with first-pass radionuclide angiography, gated blood pool scan, Tc-99m-MIBI gated SPECT, contrast ventriculography, echocardiography, and 3-dimensional magnetic resonance imaging. However, problems related to these studies include few agreement data of EDV and ESV, use of a reference method that is likely to have the same systemic errors (gated Tc-99m-MIBI SPECT), and other technical factors related to the count density of gated SPECT. With optimization of gated imaging protocols and more validation studies, gated Tl-201 SPECT would be an accurate method to provide perfusion and function information in patients with coronary artery disease.