By comparing routine FBP with algebraic iterative reconstruction, this study exploit the effect of the two SPECT reconstruction techniques on the ratio of Target/Background (T/B) and image noise. The result of research on model and clinical cases showed that the technique of OSEM could increase T/B ratio by 1.5% (heart), 3.3% (bone), 1.4% (brain). No obvious difference in image noise existed between OSEM and FBP. Compared with FBP, OSEM could improve T/B value in bone focus more significantly. Under the same injection dosage, OSEM could increase the speed of image collection by more than one time without changes in image quality and T/B ratio. The result suggested that function and clinical application of SPECT would significantly improved by substituting routine FBP with OSEM.
Algorithms ; Humans ; Image Processing, Computer-Assisted ; methods ; Tomography, Emission-Computed, Single-Photon ; methods

OBJECTIVETo investigate the value of (99)Tc(m)N-NOET dual-phase SPECT in differential diagnosis of benign and malignant lung tumors.

METHODSCT scan, early (20 to 30 min) and delayed (2 h) imaging of NOET SPECT were performed on 61 patients suspected of lung lesions before operation. The results were compared with the pathological findings. All cases were not treated with radiotherapy, chemotherapy or surgery before checks. Moreover, all patients had pathological diagnosis. To determine the value in differential diagnosis of tumors by analyzing the tumor uptake and excretion of (99)Tc(m)N-NOET, and the results were compared with that of CT.

RESULTSThe value of early T/N ratio (ER) in the malignant (G1) and benign (G2) groups was 1.25 ± 0.15 and 1.09 ± 0.11 (P < 0.001), respectively, and delayed T/N ratio (DR) was 1.40 ± 0.17 and 1.18 ± 0.21 (P < 0.001). The retention index (RI) of groups G1 was (12.22 ± 6.38)% and group G2 was (8.3 ± 10.91)%, with a non-significant difference between them (P > 0.05). The ER, DR and RI of NOET SPECT in the malignant patients were not significantly correlated with TNM staging, pathological types, tumor diameter, cavity in the lung tumor mass, history of smoking, tumor size and patient gender (P > 0.05). The sensitivity of NOET dual-phase SPECT and CT in the differential diagnosis of benign and malignant lung tumors was 94.1% vs. 90.2%, specificity was 70.0% vs. 80.0% , positive predictive value (PPV) was 94.1% vs. 95.8%, negative predictive value (NPV) was 70.0% vs. 61.5 %, and accuracy was 90.2%. vs. 88.5% (P > 0.05 for all).

CONCLUSIONS(99)Tc(m)N- NOET dual-phase SPECT could be used in differential diagnosis of benign and malignant lung tumors, with no significant differences compared with the efficacy of CT imaging. The semiquantitative indexes (ER, DR and RI) of NOET SPECT can also be used in differential diagnosis of benign and malignant lung tumors, and are not significantly correlated with TNM staging, pathological types, tumor diameter, cavity of the lung tumor mass, history of smoking, tumor size and patient gender.

Diagnosis, Differential ; Humans ; Lung Neoplasms ; diagnostic imaging ; Neoplasm Staging ; Tomography, Emission-Computed, Single-Photon ; methods

A discriminant method for optimizing activity in nuclear medicine studies is validated by comparison with ROC (received operating characteristic)-curves. The method is tested in 21 single photon emission computerized tomography (SPECT), performed with a cardiac phantom. Three different lesions (L(1), L(2) and L(3)) were placed in the myocardium-wall by pairs for each SPECT. Three activities (84, 37 or 18.5 MBq) of 99mTc were used as background. Linear discriminant analysis was used to select the parameters that characterize image quality among the measured variables in the images [(Background-to-Lesion (B/L(i)) and Signal-to-Noise (S(i)/N) ratios)]. Two clusters with different image quality (P=0.021) were obtained. The ratios B/L(1), B/L(2) and B/L(3) are the parameters used to construct the function with 100% of cases correctly classified into the clusters. The value of 37 MBq was the lowest tested activity for which good results for the B/L(i) ratios were obtained. The result coincides with the applied ROC-analysis (r=0.89).
Discriminant Analysis ; Humans ; ROC Curve ; Tomography, Emission-Computed, Single-Photon ; methods

OBJECTIVETo develop a method for (99m)Tc radiolabeling of a small molecular peptide targeting lung carcinoma and observe the biokinetics and biodistribution of the labeled peptide in normal mice and rabbits.

METHODSMAG3-peptide (cNGQGEQc) was labeled with (99m)Tc and the labeling rate was determined with paper chromatography. In vitro stability test, cysteine challenge test and serum incubation test were performed for radiochemical evaluation of the labeled peptide. Blood (99m)Tc-peptide clearance in rabbits was evaluated by determining blood radioactive concentrations at different time points after injection of 37 MBq (99m)Tc-peptide, and its dynamic distribution was investigated by SPECT imaging. The percent injected dose per gram of tissue was calculated for each organ of mice injected intravenously with 7.4 MBq (99m)Tc-peptide based on gamma counter readings.

RESULTSThe labeling rate of (99m)Tc-peptide exceeded 90%, and the radiochemical purity was 91% after placing for 12 h at room temperature and 85% after incubation at 37 degrees celsius; with human serum. The cysteine replacement rate was less than 7%, and the binding rate of (99m)Tc-peptide with serum proteins was below 5%. SPECT imaging showed that the labeled peptide could be quickly cleared from the blood in normal animals primarily through the kidneys, and the radioactivity in other tissues and organs remained low.

CONCLUSION(99m)Tc-peptide can be easily prepared with a high labeling yield. With good stability both in vitro and in vivo, (99m)Tc-peptide can be quickly cleared from the blood and excreted though the kidney with ideal biodistribution and biokinetics in vivo.

Animals ; Humans ; Male ; Mice ; Molecular Probes ; Organotechnetium Compounds ; blood ; Rabbits ; Tomography, Emission-Computed, Single-Photon ; methods

Humans ; Pilot Projects ; Prospective Studies ; Pulmonary Emphysema/surgery* ; Lung/surgery* ; Emphysema ; Perfusion ; Tomography, Emission-Computed ; Tomography ; Tomography, Emission-Computed, Single-Photon ; Pneumonectomy ; Bronchoscopy/methods*

No abstract available.
Diagnostic Imaging/*methods/trends ; Humans ; Nuclear Medicine/*methods/*trends ; Positron-Emission Tomography/methods/trends ; Tomography, Emission-Computed, Single-Photon/methods/trends

In this paper are presented and recommended the researches of the left ventricle model and optimization arithmetic based on myocardial radionuclide tomographic images (SPECT and PET). We adopted the hemispheric-cylindrical myocardial model which was largely used in quantitative analysis of myocardium. Then we adopted the radionuclide maximum counts method in LV myocardium and used the Powell optimization arithmetic to fit the myocardial model. Comparing the result from the adopted method against that of the doctors' diagnosis, we found the rate of high relevancy being 83.2%.
Algorithms ; Gated Blood-Pool Imaging ; Heart Ventricles ; diagnostic imaging ; Humans ; Image Interpretation, Computer-Assisted ; methods ; Models, Cardiovascular ; Myocardium ; Positron-Emission Tomography ; methods ; Tomography, Emission-Computed, Single-Photon ; methods

Humans ; Magnetic Resonance Imaging ; trends ; Magnetic Resonance Spectroscopy ; methods ; Molecular Imaging ; trends ; Positron-Emission Tomography ; methods ; Tomography, Emission-Computed, Single-Photon ; methods ; Ultrasonography ; trends

An effective MR and PET image registration method designed for clinical use is given in this paper. A new correlation ratio similarity measure for voxel intensity based medical image registration was adopted. Detailed discussion on methods of rigid transformation, resampling, multi-resolution medical image representation and optimization for accelerated multi-resolution registration scheme is also given in this paper. At last, experimental results based on clinical MR and PET medical images show that correlation ratio based multi-resolution registration method works well and is faster than most existing direct voxel intensity based registration methods under clinical scenario.
Algorithms ; Humans ; Image Processing, Computer-Assisted ; methods ; Magnetic Resonance Imaging ; Models, Statistical ; Tomography, Emission-Computed, Single-Photon

BACKGROUNDMyocardial perfusion grade (MPG) is an accepted method of evaluating myocardial perfusion. However, it does not take into the account, the extent of the perfusion. We hypothesized that myocardial blush area times MPG (total blush) would be more accurate than simple MPG, and yield better prognostic information.

METHODSAbout 34 patients were recruited after they had consented to both coronary angiography (CAG) and single photon emission computed tomography (SPECT), and divided into two groups. A special dedicated computer was employed to calculate the total blush. The CAG was performed as a conventional way. Scintigraphic technetium 99m methoxyisobutyl-isonitrile rest and stress images were evaluated quantitatively. The comparison was made between stenosis versus chronic total occlusion (CTO), MPG 1, 2 versus MPG 3, percutaneous intervention (PCI) successful versus failure. A correlation was made between ejection fraction (EF) and myocardial perfusion by MPG, total blush, SPECT, and syntax score.

RESULTSThe perfusion indices of total blush, summed difference score (SDS) and syntax score were insignificant between the two groups (P > 0.05). However, the left ventricular end diastolic volume was significantly larger in CTO (P < 0.05). The patients with stenosis had better MPG than with CTO (P < 0.05). The increased MPG was associated with increased total blush, higher syntax score, and EF (P < 0.05). Successful PCI resulted in better perfusion indicated by increased total blush, and MPG (P < 0.05) but successful PCI did not change syntax score, EF and SDS significantly. Multivariate linear analysis with EF as the dependent factor and syntax score, SDS, total blush, blush area, and MPG as the independent factors showed a significantly higher degree of correlation (R = 0.87, P < 0.05).

CONCLUSIONAfter PCI the total blush and EF improved significantly indicating its potential application in the future.

Aged ; Coronary Angiography ; methods ; Coronary Artery Disease ; diagnosis ; diagnostic imaging ; Female ; Humans ; Male ; Middle Aged ; Tomography, Emission-Computed, Single-Photon