Objective: The width of the photopeak energy window influences the image quality and quantitative accuracy of gamma camera imaging. We compared 20% and 15% energy windows in renal scintigraphy with 99mTc-mercaptoacety...Objective: The width of the photopeak energy window influences the image quality and quantitative accuracy of gamma camera imaging. We compared 20% and 15% energy windows in renal scintigraphy with 99mTc-mercaptoacetyltriglycine (MAG3), especially in terms of camera-based quantitative estimation of renal function. Materials and Methods: Forty patients who underwent dynamic renal scintigraphy with 99mTc-MAG3 were enrolled in this study. Images were acquired simultaneously using two energy windows centered at 140 keV and with widths of 20% and 15%. Fractional renal uptake was calculated as the ratio of initial renal uptake estimated by patient imaging to injected dose estimated by syringe imaging, and was converted to MAG3 clearance using an empirical equation determined previously from data obtained with a 20% energy window. Relative function of the right kidney was also assessed. Visual evaluation was performed to compare image quality between the 20% and 15% energy windows. Results: Both total kidney MAG3 clearance and relative function of the right kidney were identical between the 20% and 15% energy windows. Image quality was also similar irrespective of the energy window width. Conclusions: The camera-based method established using a 20% energy window is applicable for the estimation of renal function using a 15% energy window, and data obtained using 20% and 15% windows are interchangeable.展开更多
Phage display technique is a powerful approach for discovering new tumor-and organ-targeting ligands,and radiolabeled phage has a potential to analyze the phage-binding sensitivity and specific imaging.In this study,p...Phage display technique is a powerful approach for discovering new tumor-and organ-targeting ligands,and radiolabeled phage has a potential to analyze the phage-binding sensitivity and specific imaging.In this study,phage Ⅱ (the spleen-targeting phage) in mice was isolated after three rounds biopanning,and labeled by 99mTc using mercaptoacetyltriglycine (MAG3) as chelator to evaluate their binding properties in vivo.The amount of phage Ⅱ eluted from spleen was enriched by plague assay each round.99mTc-MAG3-phage Ⅱ showed the less retention in blood at any time point than half that of 99mTc-MAG3-phage Ⅰ (the radiolabeled original Ph.D-12 phage as control).The accumulation in spleen between 99mTc-MAG3-phage Ⅰ and Ⅱ was of different tendency.The highest uptake of 99mTc-MAG3-phage Ⅱ in spleen was 24.80 %ID/g at 30 min;and of 99mTc-MAG3-phage I,30.93% ID/g at 5 min.After circulating 99mTc-MAG3-phage Ⅱ for 120 min,its accumulation in spleen decreased though higher than that of 99mTc-MAG3-phage Ⅰ.In other organs,the 99mTc-MAG3-phage Ⅱ showed low retention and high spleen-to-organ or tissue ratios.In conclusion,the radiolabeled phage Ⅱ is convenient for studying the binding and specificity of spleen-targeting peptides found via phage display in vivo.展开更多
The validity of ^99mTc-YIGSR, a novel receptor radio-tracer, in imaging the Ehrlich ascites tumor was evaluated. YIGSR, a pentapeptide of laminin, was labeled with ^99mTc by using a bifunctional chelator S-Acetly-NH3-...The validity of ^99mTc-YIGSR, a novel receptor radio-tracer, in imaging the Ehrlich ascites tumor was evaluated. YIGSR, a pentapeptide of laminin, was labeled with ^99mTc by using a bifunctional chelator S-Acetly-NH3-MAG3. The MIBI was labeled with ^99mTc by following the kit instruction. The mice of tumor group were intravenously injected 1-2 mCi of ^99mTc-YIGSR or ^99mTc-MIBI via caudal vein, immobilized and imaged under a Gamma camera. The same procedure was performed in mice of blockade group, in which the unlabeled YIGSR was previously injected to block the receptor-recognition sites, and inflammation group serving as control. The reverse-phase Sep-Pak C18 chromatogram was found to have an essentially complete conjugation between YIGSR and S-Acetly-NH3-MAG3. The conjugated YIGSR could be radio-labeled successfully with ^99mTC at room temperature and neutral pH, with a radio-labeling yield of 62%. Without the chelator S-Acetly-NH3-MAG3, the YIGSR was labeled with ^99mTc at an efficiency of 4%. The imagological study revealed obvious tumor accumulation of ^99mTc-YIGSR 15 min after the injection, and the uptake peaked after 3 h with a tumor-to-muscle ratio （T/M） of 11.36. The radio-tracer was slowly cleared up and resulted in a T/M of 3.01 at the 8th h after the injection. As for blocked group, the tumor uptake of radiotracer was significantly lower, with the highest T/M being 4.61 after 3 h and 0.89 after 8 h. The T/M was 3.72 at the 3rd h and 1.29 at the 8th h after the ^99mTc-YIGSR injection in the inflammatory group. The T/M was significantly higher in tumor group than in inflammatory group or control group （P〈0.001）. In the ^99mTc-MIBI group, the T/M was 1.40 at the 3rd h and 0.55 at the 8th h after the injection, which showed a significant difference as compared with ^99mTc-YIGSR （P〈0.001）. It is concluded that YIGSR can be successfully radiolabelled by using S-Acetly-NH3-MAG3. ^99mTc-YIGSR has many advantages in tumor imaging, such as quick and clear visualization, high sensitivity and specificity, and satisfactory target/non-target ratio （N/NT）. It promises to be tumor radio-tracer.展开更多
文摘Objective: The width of the photopeak energy window influences the image quality and quantitative accuracy of gamma camera imaging. We compared 20% and 15% energy windows in renal scintigraphy with 99mTc-mercaptoacetyltriglycine (MAG3), especially in terms of camera-based quantitative estimation of renal function. Materials and Methods: Forty patients who underwent dynamic renal scintigraphy with 99mTc-MAG3 were enrolled in this study. Images were acquired simultaneously using two energy windows centered at 140 keV and with widths of 20% and 15%. Fractional renal uptake was calculated as the ratio of initial renal uptake estimated by patient imaging to injected dose estimated by syringe imaging, and was converted to MAG3 clearance using an empirical equation determined previously from data obtained with a 20% energy window. Relative function of the right kidney was also assessed. Visual evaluation was performed to compare image quality between the 20% and 15% energy windows. Results: Both total kidney MAG3 clearance and relative function of the right kidney were identical between the 20% and 15% energy windows. Image quality was also similar irrespective of the energy window width. Conclusions: The camera-based method established using a 20% energy window is applicable for the estimation of renal function using a 15% energy window, and data obtained using 20% and 15% windows are interchangeable.
基金Supported by National Natural Science Foundation of China (No. 20771011 and 21071010)the Ministry of Science and Technology of China (No.2006CB705700)
文摘Phage display technique is a powerful approach for discovering new tumor-and organ-targeting ligands,and radiolabeled phage has a potential to analyze the phage-binding sensitivity and specific imaging.In this study,phage Ⅱ (the spleen-targeting phage) in mice was isolated after three rounds biopanning,and labeled by 99mTc using mercaptoacetyltriglycine (MAG3) as chelator to evaluate their binding properties in vivo.The amount of phage Ⅱ eluted from spleen was enriched by plague assay each round.99mTc-MAG3-phage Ⅱ showed the less retention in blood at any time point than half that of 99mTc-MAG3-phage Ⅰ (the radiolabeled original Ph.D-12 phage as control).The accumulation in spleen between 99mTc-MAG3-phage Ⅰ and Ⅱ was of different tendency.The highest uptake of 99mTc-MAG3-phage Ⅱ in spleen was 24.80 %ID/g at 30 min;and of 99mTc-MAG3-phage I,30.93% ID/g at 5 min.After circulating 99mTc-MAG3-phage Ⅱ for 120 min,its accumulation in spleen decreased though higher than that of 99mTc-MAG3-phage Ⅰ.In other organs,the 99mTc-MAG3-phage Ⅱ showed low retention and high spleen-to-organ or tissue ratios.In conclusion,the radiolabeled phage Ⅱ is convenient for studying the binding and specificity of spleen-targeting peptides found via phage display in vivo.
基金This project was supported by a grant from the National Natural Sciences Foundation of China (No 30400170)
文摘The validity of ^99mTc-YIGSR, a novel receptor radio-tracer, in imaging the Ehrlich ascites tumor was evaluated. YIGSR, a pentapeptide of laminin, was labeled with ^99mTc by using a bifunctional chelator S-Acetly-NH3-MAG3. The MIBI was labeled with ^99mTc by following the kit instruction. The mice of tumor group were intravenously injected 1-2 mCi of ^99mTc-YIGSR or ^99mTc-MIBI via caudal vein, immobilized and imaged under a Gamma camera. The same procedure was performed in mice of blockade group, in which the unlabeled YIGSR was previously injected to block the receptor-recognition sites, and inflammation group serving as control. The reverse-phase Sep-Pak C18 chromatogram was found to have an essentially complete conjugation between YIGSR and S-Acetly-NH3-MAG3. The conjugated YIGSR could be radio-labeled successfully with ^99mTC at room temperature and neutral pH, with a radio-labeling yield of 62%. Without the chelator S-Acetly-NH3-MAG3, the YIGSR was labeled with ^99mTc at an efficiency of 4%. The imagological study revealed obvious tumor accumulation of ^99mTc-YIGSR 15 min after the injection, and the uptake peaked after 3 h with a tumor-to-muscle ratio （T/M） of 11.36. The radio-tracer was slowly cleared up and resulted in a T/M of 3.01 at the 8th h after the injection. As for blocked group, the tumor uptake of radiotracer was significantly lower, with the highest T/M being 4.61 after 3 h and 0.89 after 8 h. The T/M was 3.72 at the 3rd h and 1.29 at the 8th h after the ^99mTc-YIGSR injection in the inflammatory group. The T/M was significantly higher in tumor group than in inflammatory group or control group （P〈0.001）. In the ^99mTc-MIBI group, the T/M was 1.40 at the 3rd h and 0.55 at the 8th h after the injection, which showed a significant difference as compared with ^99mTc-YIGSR （P〈0.001）. It is concluded that YIGSR can be successfully radiolabelled by using S-Acetly-NH3-MAG3. ^99mTc-YIGSR has many advantages in tumor imaging, such as quick and clear visualization, high sensitivity and specificity, and satisfactory target/non-target ratio （N/NT）. It promises to be tumor radio-tracer.
