This study investigated the method to adjust acquisition time(a) and injection dose(i) to make the best basal and subtraction images in consecutive SPECT. Image quality was assumed to be mainly affected by signal to noise ratio(S/N). Basal image was subtracted from the second image consecutively acquired at the same position. We calculated S/N ratio in basal SPECT images(S1/N1) and subtraction SPECT images(Ss/Ns) to find a(time) and i(dose) to maximize S/N of both images at the same time. From phantom images, we drew the relation of image counts and a(time) and i(dose) in our system using fanbeam-high-resolution collimated triple head SPECT. Noise by imaging process depended on Poisson distribution. We took maximum tolerable duration of consecutive acquisition as 30 minutes and maximum injectible dose as 1,850MBq(50 mCi)(sum of two injections) per study. Counts of second-acquired image(S2), counts(Ss) and noise(Ns) of subtraction SPECT were as follows. C1 was the coefficient of measurement with our system.
Acetazolamide* ; Brain* ; Head ; Noise ; Perfusion* ; Signal-To-Noise Ratio ; Tomography, Emission-Computed, Single-Photon*

A technique for Thallium-201 imaging after two separate injections of the tracer, which took less than I hour, was performed to evaluate if this technique could be used clinically as a noninvasive screening test of angina pectoris. 29 patients who complained of chest pain were included in this study: 18 patients were proven to have coronary artery disease by coronary angiography and 11 patients had normal coronary arteries. With the patient supine at rest, 1.0 mCi of Thallium was injected intravenously and imaging was performed in the anterior and 50degrees left anterior oblique projections for a preset time according to Okada's protocol. Immediately after acquisition of the rest images, without moving the camera head, an infusion of dipyridamole was done at the rate of 0.14 mg/Kg/min for 4 minutes. Two minutes after stopping the infusion, 1.0 mCi of Thallium was injected intravenously and 50degrees left anterior oblique and anterior projection images were acquired. Images of the same projection were realigned using computer image registration approach (PDP-11/34 computer of DEC company). The rest image was then subtracted from the realigned dipyridamole image to produce an image representing perfusion during dipyridamole induced hyperemia (subtraction image). The results were as follows; 1) All of the subtraction images were of adequate quality for interpretation. 2) 16 cases in 18 patients of angina pectoris and 1 case in 11 normal control showed perfusion defects, so the over all sensitivity and specificity of the subtraction versus rest Thallium image technique for diagnosis of angina pectoris were 89% and 91%, respectively. 3) All patients (8 cases) whose left ventriculography revealed abnormality of regional wall motion showed perfusion defects in corresponding segments. But qualitative analysis of Thallium image could not predict if the patient whose Thallium image revealed perfusion defect has abnormality of regional wall motion. 4) segmental analysis was performed to know the association between the site of coronary artery stenosis and the perfusion defects in Thallium scan, which revealed the sensitivities for detecting stenosis of LCX, LAD & RCA were 50-60% in range and the range of specificities were 89-92%. 5) Adverse effects of dipyridamole were headache (2 cases) and chest pain (4 cases) but aminophylline was not needed in any case. In conclusion, split dose Thallium dipyridamole scan can be used as a noninvasive screening test of angina pectoris reducing the total duration of imaging to less than one hour. Futher applications of this technique may include the assessment of myocardial perfusion before and immediately after coronary angioplasty and coronary artery bypass graft and the evaluation of the impact of pharmacotheraphy on regional myocardial perfusion.
Aminophylline ; Angina Pectoris* ; Angioplasty ; Chest Pain ; Constriction, Pathologic ; Coronary Angiography ; Coronary Artery Bypass ; Coronary Artery Disease ; Coronary Stenosis ; Coronary Vessels ; Diagnosis* ; Dipyridamole* ; Head ; Headache ; Humans ; Hyperemia ; Mass Screening ; Perfusion ; Sensitivity and Specificity ; Thallium ; Transplants

No abstract available.
Coronary Artery Disease* ; Coronary Vessels* ; Dipyridamole* ; Perfusion*

No abstract available.
Brain* ; Tomography, Emission-Computed, Single-Photon*

OBJECTIVES: It is suggested that frequency of low turnover bone disease is much higher in diabetic renal osteodystrophy. We tried to find out whether bone scan images show less 99mTc-MDP uptake in diabetic renal ostwdystrophy. METHODS: We compared bone scan images of renal failure patients with and without diabetes. The number of patients studied was 134 (43 patients had diabetes and 91 patients did not). Two experienced nuclear physicians read Tc-99m-MDP bone scan twice separately and gave the score either 1 or 0 on 6 areas; axial skeleton, long bone, skull and mandible, periarticular areas, costochondral junction and sternum. The means of summed scores were compared using Students t-test. To exclude the effects of sex, age and serum creatinine concentration, we analysed these factors together with the effect of diabetes using analysis of covariance. We also interpreted on bone scan images, as classical renal osteodystrophy, renal failure and normal. RESULTS: The intra- and interobserver variations were very low. Patients of diabetes group showed significantly lower mean of summed score(2.0+/-0.95) compared to patients of non-DM group(3.3+/-1.2). Analysis of covariance revealed that lower score of diabetes group was independent of sex, age and serum creatinine level. of diabetes group, 2 nuclear physicians interpreted bone scans as classical renal osteodystrophy in 60% and 56%, However, they interpreted bone scans of non-DM group in 80%, 88%(between-observer k: 0.74). Chi-square test showed that this difference was statistically significant (p<0.05). CONCLUSION: Bone scan image of diabetic renal osteodystrophy showed less 99mTc-MDP uptake, which meant low osteoblastic activity. This influence of diabetes upon bone uptake was significant after considering other confounding factors.
Bone Diseases ; Creatinine ; Diabetes Mellitus ; Humans ; Kidney Failure, Chronic* ; Mandible ; Observer Variation ; Osteoblasts ; Renal Insufficiency ; Renal Osteodystrophy* ; Skeleton ; Skull ; Sternum ; Technetium Tc 99m Medronate

No abstract available.
Coronary Artery Disease* ; Coronary Vessels* ; Electrocardiography* ; ROC Curve*

No abstract available.
Brain Neoplasms* ; Brain* ; Tomography, Emission-Computed, Single-Photon*

No abstract available.
Abscess* ; Technetium Tc 99m Exametazime*

No abstract available.
Humans ; Neoplasm Metastasis* ; Stomach Neoplasms* ; Stomach* ; Technetium Tc 99m Medronate*

No abstract available.
Captopril* ; Diagnosis* ; Hypertension, Renovascular* ; Radionuclide Imaging*