AIM To directly radiolabel an anti-hepatomamAb fragment HAb18 F（ab’）<sub>2</sub> with <sup>99m</sup>Tc bystannous-reduced method,and assess thestability,biodistribution and radioimmun-oimag...AIM To directly radiolabel an anti-hepatomamAb fragment HAb18 F（ab’）<sub>2</sub> with <sup>99m</sup>Tc bystannous-reduced method,and assess thestability,biodistribution and radioimmun-oimaging（RⅡ）.METHODS Immunoreactive fraction wasdetermined according to Lindmo’s method.Ellman’s reagent was used to determine thenumber of thiols in the reduced F（ab’）<sub>2</sub>.Labelingefficiency and homogeneity were measured bypaper chromatography,sodium dodecylsulphatepolyacrylamide gel electrophoresis（SDS-PAGE）and autoradiography.Challenge assay involvedthe incubation of aliquots of labeled antibody inethylenediaminetetraacetate（ EDTA ）and L-cysteine（L-cys）solutions with different molarratio at 37℃ for 1h,respectively.Investigationsin vivo utilized nude mice bearing humanhepatocellular carcinoma（HHCC）xenograftswith gamma camera imaging and tissuebiodistribution studies at regular intervals.RESULTS The labeling procedure was finishedwithin 1.5 h compared with the'pretinning'method which would take at least 21h.In vitrostudies demonstrated that the radiolabeled mAbfragment was homogeneous and retained itsimmunoreactivity.Challenge studies indicatedthat <sup>99m</sup>Tc-labeled HAb18 F（ab’）<sub>2</sub> in EDTA is morestable than in L-cys.Imaging and biodistribution showed a significant tumor uptake at 24 h post-injection of <sup>99m</sup>Tc-labeled HAb18 F（ab’）<sub>2</sub>.Theblood,kidney,liver and tumor uptakes at 24hwere 0.56±0.09,56.45±11.36,1.43±0.27 and6.57±3.01（%ID/g）,respectively.CONCLUSION <sup>99m</sup>Tc-HAb18 F（ab’）<sub>2</sub> conjugateprepared by this direct method appears to be aneffective way to detect hepatoma in nude micemodel.展开更多
To explore the effect of technetium-99 conjugated with methylene diphosphonate ( 99 Tc-MDP) on IgM-RF, IgG-RF and IgA-RF (RFs), 47 cases were selected for study, including 33 patients with rheumatoid arthritis (RA...To explore the effect of technetium-99 conjugated with methylene diphosphonate ( 99 Tc-MDP) on IgM-RF, IgG-RF and IgA-RF (RFs), 47 cases were selected for study, including 33 patients with rheumatoid arthritis (RA) and 15 patients with joint pain/arthritis. After 99 Tc-MDP for drips model being given to the patients by intravenous drip 0.2 g daily for 5 days, the injection A and B models of 99 Tc-MDP were used to the patients by intravenous injection one set daily for 10 days, that was one course of treatment. The next course started after 10 days. Each case used it from 2 to 4 courses of treatment. The RFs in serum were determined by the method of enzyme-linked immunoabsorption assay (ELISA) before and after 2 and 4 courses of treatment. In the patients with RA, the concentrations of IgM-RF were 296.2±108.4 IU/ml, 189.5±92.3 IU/ml and 107.8±72.5 IU/ml; the concentrations of IgG-RF were 325.6±126.2 IU/ml, 209.7±98.2 IU/ml and 160.2±80.8 IU/ml; the concentrations of IgA-RF were 330.4±136.3 IU/ml, 210.7±89.2 IU/ml and 148.8±72.2 IU/ml before and after 2 and 4 courses of treatment, respectively. The concentrations of the above RFs were significantly lower after 2 and 4 courses than those before treatment ( P <0.05 and P <0.01). There was no significant difference in RFs concentrations in the patients with joint pain/arthritis before and after use of 99 Tc-MDP. In the patients with positive RFs before treatment, the RFs concentrations were decreased significantly after 2 and 4 courses of treatment ( P <0.05 and P <0.01). There was no obvious change of RFs concentrations in the patients with negative RFs after treatment of 99 Tc-MDP. It was concluded that 99 Tc-MDP could obviously reduce the abnormally high concentrations of RFs, but not influence the normal RFs, which indicated that 99 Tc-MDP has an important effect on controlling the activities of RA.展开更多
The complex 99m TcN CPDTC(CPDTC: N cyclopropyl dithiocarbamate trihydrate) is synthesized through ligand exchange reaction. The two step procedure involves the initial reaction of 99m TcO - 4 with succinic dihydrazide...The complex 99m TcN CPDTC(CPDTC: N cyclopropyl dithiocarbamate trihydrate) is synthesized through ligand exchange reaction. The two step procedure involves the initial reaction of 99m TcO - 4 with succinic dihydrazide(SDH) as a donor of nitrido ligand(N 3- ) in the presence of stannous chloride dihydrate as reducing agent and propylenediamine tetraacetic acid(PDTA) as complex agent, followed by the addition of sodium N cyclopropyl dithiocarbamate trihydrate. The radiochemical purity(RCP) of the product is over 90% as measured by thin layer chromatography(TLC). It is stable over 6 h at room temperature. Its partition coefficient indicates it is a good lipophilic complex. The biodistribution results in mice indicate that 99m TcN CPDTC is significantly retained into the brain. The brain uptake(%, ID/g) is 4.64, 3 54 and 2.59 and the brain/blood ratio is 1.08, 1.27 and 1.28 at 5, 30 and 60 min post injection respectively. These results suggest potential usefulness of the complex as a brain perfusion imaging agent.展开更多
Small peptide-based compounds have attracted an enormous interest as carrier molecules to selectively de- liver radionuclides to target tissues, sparing critical normal organs. When looking for "matched pairs&quo...Small peptide-based compounds have attracted an enormous interest as carrier molecules to selectively de- liver radionuclides to target tissues, sparing critical normal organs. When looking for "matched pairs" of radionuclides, suitable for radiolabeling of peptides for diagnosis and therapy, technetium and rhenium represent an almost ideal constellation. The important role of technetium-99m and Re-186/188 is based on the decay characteristics, suitable for tumor diagnosis and therapy. Tc-99m and Re-188 are readily available by either a 99Mo/99mTc or the 188W/188Re ra- dionuclide generator system. Furthermore, technetium and rhenium are chemically related and share structural as well as reactive similarities, which prompt an attractive "matched-pair" situation. This article shows an overview of 99mTc- and 186/188Re-radiolabeled peptides that have been tested for their potential use as imaging and therapeutic agents in oncological diseases.展开更多
AIM:To explore and compare the radiochemical behavior and biological property of anti-sense oligonuc-leotide (ASON) labeled with technetium-99m using N-hydroxysuccinimidyl S-acetylmercaptoacetyltriglycl ine (NHS-MAG3)...AIM:To explore and compare the radiochemical behavior and biological property of anti-sense oligonuc-leotide (ASON) labeled with technetium-99m using N-hydroxysuccinimidyl S-acetylmercaptoacetyltriglycl ine (NHS-MAG3) and hydrazinonictinamide derivative (HYNIC). METHODS:After HYNIC and NHS-MAG3 were synthesized, ASON was labeled with technetium-99m using HYNIC and NHS-MAG3 as a bifunctional chelator. The in vivo and in vitro stability, binding rates of labeled compounds to serum albumen, biodistribution of 99mTc-MAG3-ASON and 99mTc-HYNIC-ASON in BALB/C mouse and its HT29 tumor cellular uptake were compared. RESULTS:The labeling efficiency and stability of 99mTc-MAG3-ASON were significantly higher than those of 99mTc-HYNIC-ASON (P = 0.02, and P = 0.03, respectively). 99mTc-MAG3-ASON had a significantly lower rate of binding to serum albumen than 99mTc-HYNIC-ASON (P < 0.05). In contrast to 99mTc-HYNIC-ASON, the biodistribution of 99mTc-MAG3-ASON was significantly lower in blood, heart, liver and stomach (P < 0.05), slightly lower in intestines and spleen (P > 0.05) and significantly higher in lung and kidney (P < 0.05). The HT29 tumor cellular uptake rate of 99mTc-MAG3-ASON was significantly higher than that of 99mTc-HYNIC-ASON (P < 0.05). CONCLUSION:99mTc-MAG3-ASON shows superior radiochemical behaviors and biological properties than 99mTc-HYNIC-ASON. 99mTc-MAG3-ASON is a potential radiopharmaceutical agent for in vivo application.展开更多
We report herein a case of a 40-year-old male patient with chronic renal failure presenting a severe hyperparathyroidism with an elevation of parathormone level evaluated in nuclear medicine department for MIBI-Techne...We report herein a case of a 40-year-old male patient with chronic renal failure presenting a severe hyperparathyroidism with an elevation of parathormone level evaluated in nuclear medicine department for MIBI-Technetium-99m parathyroid scintigraphy. The parathyroid scintigraphy revealed the appearance of a preferential fixation of the MIBI-99mTc opposite the lower left pole of the thyroid and opposite the upper part of the right hemi thorax. A subsequent single-photon emission computed tomography-computed tomography focused on the cervico-thoracic region was performed and showed an ectopic parathyroid adenoma associated with an incidental brown tumor mimicking bone and lung metastases. Our case report confirms the usefulness of additional hybrid SPECT-CT imaging in the management of hyperparathyroidism.展开更多
Radiopharmaceuticals are used in nuclear medicine for diagnostic or therapeutic acts. The short decay half-lives of medical radioisotopes, especially those used for diagnostics, imply that they should be produced cont...Radiopharmaceuticals are used in nuclear medicine for diagnostic or therapeutic acts. The short decay half-lives of medical radioisotopes, especially those used for diagnostics, imply that they should be produced continuously and transported as quickly as possible to the medical units where they are used. Neutron-rich medical radioisotopes are generally produced in research reactors, like technetium-99m, lutetium-177, holmium-166 and iodine-131. On the other hand, proton-rich radioisotopes are produced via reactions with charged particles from accelerators like fluorine-18, gallium-67, iodine-123 and thallium-201. Beside this, innovative nuclear reactors are advocated as solutions to the issues of nuclear waste production and proliferation threats. Fast neutron, thorium-cycle and accelerator-driven subcritical (ADS) reactors are some of the most promising of them, proposed as safer fuel breeders and “waste burners”. This article examines the use of a fast thorium-cycle ADS with liquid lead-bismuth eutectic coolant for the production of molybdenum-99/technetium-99m and lutetium-177. Burnup simulation has been made with the Monte-Carlo (MC) code SERPENT. It is demonstrated that MC codes can advantageously be used to determine the optimal irradiation time for a given radioisotope in a realistic reactor core. It is also shown that fast thorium-cycle ADS is an economical option for the production of medical radioisotopes.展开更多
AIM: To evaluate the role of pentavalent Tc-99m dimercaptosuccinic acid [Tc-99m (V) DMSA] in the diagnosis of ischemic colitis. METHODS: Fourteen patients with endoscopically and histologically confirmed ischemic coli...AIM: To evaluate the role of pentavalent Tc-99m dimercaptosuccinic acid [Tc-99m (V) DMSA] in the diagnosis of ischemic colitis. METHODS: Fourteen patients with endoscopically and histologically confirmed ischemic colitis were included in the study. Tc-99m (V) DMSA scintigraphy was performed within 2 d after colonoscopy. Images were considered positive when an area of increased activity was observed in the region of interest and negative when no abnormal tracer uptake was detected. RESULTS: In 3 out of the 14 patients, Tc-99m (V) DMSA images showed moderate activity in the bowel. The scintigraphic results corresponded with the endoscopic findings. In the other 11 patients, no abnormal tracer uptake was detected in the abdomen. CONCLUSION: Besides the limited number of patients, Tc-99m (V) DMSA could not be considered as a useful imaging modality for the evaluation of ischemic colitis.展开更多
Background Technetium-99m or 99mTC is widely used for labeling peptide in nuclear medicine. Somatostatin and its analog can inhibit tumor cell growth after binding with its receptor. This research was to study the pre...Background Technetium-99m or 99mTC is widely used for labeling peptide in nuclear medicine. Somatostatin and its analog can inhibit tumor cell growth after binding with its receptor. This research was to study the preclinical effect of a new 99rnTc-6-hydrazinopyridine-3-carboxylic acid （HYNIC）-depreotide, indirect 99rnTc labeling of depreotide using HYNIC as a bifunctional chelator. Methods The cyclopeptide, cyclo-[（N-Me） Phe-Tyr-D-Trp-Lys-VaI-Hcy], the linear peptide, and [CICH2-CO.^-Dap-Lys- Cys-Lys-amide] were synthesized by Fmoc solid-phase synthesis. The cyclopeptide and the linear peptide were linked by liquid-phase synthesis. The product depreotide was isolated and purified by high performance liquid chromatography and was confirmed by mass spectrography. Depreotide was labeled with egmTc through a direct labeling method, using HYNIC as a bifunctional chelator. Paper chromatography method was used to calculate the labeling rate, and through the comparative analysis selected the best mark conditions. The new 99mTc-HYNIC-depreotide was tested by high-performance liquid chromatography （HPLC）. The internalization and externalization rates of the new 99mTc-HYNIC-depreotide were studied in A549 cells. Furthermore, biodistribution of the radiopeptide was studied in nude mice, bearing tumors from human lung carcinoma cells SPC-A1. Results The molecular of synthesize depreotide was 1358, and the purity of it was 95.29%. The labeling efficiency of 99mTc-HYNIC-depreotide was highest at pH 6.0 and 15℃, about （70.95±0.84）%. The labeling rate of the new 99mTc-HYNIC-depreotide rose to a peak of （20.75±0.48）% at 60 minutes in A549 cells at 37℃ and decreased slightly later, while it elevated gradually during the time course at 4℃ and 25℃. The internalization rate of the new 99rnTc-HYNIC-depreotide at 37℃ increased gradually and reached the peak of 84.4% in 120 minutes, while the externalization rate of the new 99mTc-HYNIC-depreotide was always less than 20%. In mice bearing the experimental 展开更多
基金National Natural Science Foundation of China,No.39700175
文摘AIM To directly radiolabel an anti-hepatomamAb fragment HAb18 F（ab’）<sub>2</sub> with <sup>99m</sup>Tc bystannous-reduced method,and assess thestability,biodistribution and radioimmun-oimaging（RⅡ）.METHODS Immunoreactive fraction wasdetermined according to Lindmo’s method.Ellman’s reagent was used to determine thenumber of thiols in the reduced F（ab’）<sub>2</sub>.Labelingefficiency and homogeneity were measured bypaper chromatography,sodium dodecylsulphatepolyacrylamide gel electrophoresis（SDS-PAGE）and autoradiography.Challenge assay involvedthe incubation of aliquots of labeled antibody inethylenediaminetetraacetate（ EDTA ）and L-cysteine（L-cys）solutions with different molarratio at 37℃ for 1h,respectively.Investigationsin vivo utilized nude mice bearing humanhepatocellular carcinoma（HHCC）xenograftswith gamma camera imaging and tissuebiodistribution studies at regular intervals.RESULTS The labeling procedure was finishedwithin 1.5 h compared with the'pretinning'method which would take at least 21h.In vitrostudies demonstrated that the radiolabeled mAbfragment was homogeneous and retained itsimmunoreactivity.Challenge studies indicatedthat <sup>99m</sup>Tc-labeled HAb18 F（ab’）<sub>2</sub> in EDTA is morestable than in L-cys.Imaging and biodistribution showed a significant tumor uptake at 24 h post-injection of <sup>99m</sup>Tc-labeled HAb18 F（ab’）<sub>2</sub>.Theblood,kidney,liver and tumor uptakes at 24hwere 0.56±0.09,56.45±11.36,1.43±0.27 and6.57±3.01（%ID/g）,respectively.CONCLUSION <sup>99m</sup>Tc-HAb18 F（ab’）<sub>2</sub> conjugateprepared by this direct method appears to be aneffective way to detect hepatoma in nude micemodel.
文摘To explore the effect of technetium-99 conjugated with methylene diphosphonate ( 99 Tc-MDP) on IgM-RF, IgG-RF and IgA-RF (RFs), 47 cases were selected for study, including 33 patients with rheumatoid arthritis (RA) and 15 patients with joint pain/arthritis. After 99 Tc-MDP for drips model being given to the patients by intravenous drip 0.2 g daily for 5 days, the injection A and B models of 99 Tc-MDP were used to the patients by intravenous injection one set daily for 10 days, that was one course of treatment. The next course started after 10 days. Each case used it from 2 to 4 courses of treatment. The RFs in serum were determined by the method of enzyme-linked immunoabsorption assay (ELISA) before and after 2 and 4 courses of treatment. In the patients with RA, the concentrations of IgM-RF were 296.2±108.4 IU/ml, 189.5±92.3 IU/ml and 107.8±72.5 IU/ml; the concentrations of IgG-RF were 325.6±126.2 IU/ml, 209.7±98.2 IU/ml and 160.2±80.8 IU/ml; the concentrations of IgA-RF were 330.4±136.3 IU/ml, 210.7±89.2 IU/ml and 148.8±72.2 IU/ml before and after 2 and 4 courses of treatment, respectively. The concentrations of the above RFs were significantly lower after 2 and 4 courses than those before treatment ( P <0.05 and P <0.01). There was no significant difference in RFs concentrations in the patients with joint pain/arthritis before and after use of 99 Tc-MDP. In the patients with positive RFs before treatment, the RFs concentrations were decreased significantly after 2 and 4 courses of treatment ( P <0.05 and P <0.01). There was no obvious change of RFs concentrations in the patients with negative RFs after treatment of 99 Tc-MDP. It was concluded that 99 Tc-MDP could obviously reduce the abnormally high concentrations of RFs, but not influence the normal RFs, which indicated that 99 Tc-MDP has an important effect on controlling the activities of RA.
文摘The complex 99m TcN CPDTC(CPDTC: N cyclopropyl dithiocarbamate trihydrate) is synthesized through ligand exchange reaction. The two step procedure involves the initial reaction of 99m TcO - 4 with succinic dihydrazide(SDH) as a donor of nitrido ligand(N 3- ) in the presence of stannous chloride dihydrate as reducing agent and propylenediamine tetraacetic acid(PDTA) as complex agent, followed by the addition of sodium N cyclopropyl dithiocarbamate trihydrate. The radiochemical purity(RCP) of the product is over 90% as measured by thin layer chromatography(TLC). It is stable over 6 h at room temperature. Its partition coefficient indicates it is a good lipophilic complex. The biodistribution results in mice indicate that 99m TcN CPDTC is significantly retained into the brain. The brain uptake(%, ID/g) is 4.64, 3 54 and 2.59 and the brain/blood ratio is 1.08, 1.27 and 1.28 at 5, 30 and 60 min post injection respectively. These results suggest potential usefulness of the complex as a brain perfusion imaging agent.
文摘Small peptide-based compounds have attracted an enormous interest as carrier molecules to selectively de- liver radionuclides to target tissues, sparing critical normal organs. When looking for "matched pairs" of radionuclides, suitable for radiolabeling of peptides for diagnosis and therapy, technetium and rhenium represent an almost ideal constellation. The important role of technetium-99m and Re-186/188 is based on the decay characteristics, suitable for tumor diagnosis and therapy. Tc-99m and Re-188 are readily available by either a 99Mo/99mTc or the 188W/188Re ra- dionuclide generator system. Furthermore, technetium and rhenium are chemically related and share structural as well as reactive similarities, which prompt an attractive "matched-pair" situation. This article shows an overview of 99mTc- and 186/188Re-radiolabeled peptides that have been tested for their potential use as imaging and therapeutic agents in oncological diseases.
基金The National Natural Science Foundation of China, No. 39870200
文摘AIM:To explore and compare the radiochemical behavior and biological property of anti-sense oligonuc-leotide (ASON) labeled with technetium-99m using N-hydroxysuccinimidyl S-acetylmercaptoacetyltriglycl ine (NHS-MAG3) and hydrazinonictinamide derivative (HYNIC). METHODS:After HYNIC and NHS-MAG3 were synthesized, ASON was labeled with technetium-99m using HYNIC and NHS-MAG3 as a bifunctional chelator. The in vivo and in vitro stability, binding rates of labeled compounds to serum albumen, biodistribution of 99mTc-MAG3-ASON and 99mTc-HYNIC-ASON in BALB/C mouse and its HT29 tumor cellular uptake were compared. RESULTS:The labeling efficiency and stability of 99mTc-MAG3-ASON were significantly higher than those of 99mTc-HYNIC-ASON (P = 0.02, and P = 0.03, respectively). 99mTc-MAG3-ASON had a significantly lower rate of binding to serum albumen than 99mTc-HYNIC-ASON (P < 0.05). In contrast to 99mTc-HYNIC-ASON, the biodistribution of 99mTc-MAG3-ASON was significantly lower in blood, heart, liver and stomach (P < 0.05), slightly lower in intestines and spleen (P > 0.05) and significantly higher in lung and kidney (P < 0.05). The HT29 tumor cellular uptake rate of 99mTc-MAG3-ASON was significantly higher than that of 99mTc-HYNIC-ASON (P < 0.05). CONCLUSION:99mTc-MAG3-ASON shows superior radiochemical behaviors and biological properties than 99mTc-HYNIC-ASON. 99mTc-MAG3-ASON is a potential radiopharmaceutical agent for in vivo application.
文摘We report herein a case of a 40-year-old male patient with chronic renal failure presenting a severe hyperparathyroidism with an elevation of parathormone level evaluated in nuclear medicine department for MIBI-Technetium-99m parathyroid scintigraphy. The parathyroid scintigraphy revealed the appearance of a preferential fixation of the MIBI-99mTc opposite the lower left pole of the thyroid and opposite the upper part of the right hemi thorax. A subsequent single-photon emission computed tomography-computed tomography focused on the cervico-thoracic region was performed and showed an ectopic parathyroid adenoma associated with an incidental brown tumor mimicking bone and lung metastases. Our case report confirms the usefulness of additional hybrid SPECT-CT imaging in the management of hyperparathyroidism.
文摘Radiopharmaceuticals are used in nuclear medicine for diagnostic or therapeutic acts. The short decay half-lives of medical radioisotopes, especially those used for diagnostics, imply that they should be produced continuously and transported as quickly as possible to the medical units where they are used. Neutron-rich medical radioisotopes are generally produced in research reactors, like technetium-99m, lutetium-177, holmium-166 and iodine-131. On the other hand, proton-rich radioisotopes are produced via reactions with charged particles from accelerators like fluorine-18, gallium-67, iodine-123 and thallium-201. Beside this, innovative nuclear reactors are advocated as solutions to the issues of nuclear waste production and proliferation threats. Fast neutron, thorium-cycle and accelerator-driven subcritical (ADS) reactors are some of the most promising of them, proposed as safer fuel breeders and “waste burners”. This article examines the use of a fast thorium-cycle ADS with liquid lead-bismuth eutectic coolant for the production of molybdenum-99/technetium-99m and lutetium-177. Burnup simulation has been made with the Monte-Carlo (MC) code SERPENT. It is demonstrated that MC codes can advantageously be used to determine the optimal irradiation time for a given radioisotope in a realistic reactor core. It is also shown that fast thorium-cycle ADS is an economical option for the production of medical radioisotopes.
文摘AIM: To evaluate the role of pentavalent Tc-99m dimercaptosuccinic acid [Tc-99m (V) DMSA] in the diagnosis of ischemic colitis. METHODS: Fourteen patients with endoscopically and histologically confirmed ischemic colitis were included in the study. Tc-99m (V) DMSA scintigraphy was performed within 2 d after colonoscopy. Images were considered positive when an area of increased activity was observed in the region of interest and negative when no abnormal tracer uptake was detected. RESULTS: In 3 out of the 14 patients, Tc-99m (V) DMSA images showed moderate activity in the bowel. The scintigraphic results corresponded with the endoscopic findings. In the other 11 patients, no abnormal tracer uptake was detected in the abdomen. CONCLUSION: Besides the limited number of patients, Tc-99m (V) DMSA could not be considered as a useful imaging modality for the evaluation of ischemic colitis.
基金the National Natural Science Foundation of China
文摘Background Technetium-99m or 99mTC is widely used for labeling peptide in nuclear medicine. Somatostatin and its analog can inhibit tumor cell growth after binding with its receptor. This research was to study the preclinical effect of a new 99rnTc-6-hydrazinopyridine-3-carboxylic acid （HYNIC）-depreotide, indirect 99rnTc labeling of depreotide using HYNIC as a bifunctional chelator. Methods The cyclopeptide, cyclo-[（N-Me） Phe-Tyr-D-Trp-Lys-VaI-Hcy], the linear peptide, and [CICH2-CO.^-Dap-Lys- Cys-Lys-amide] were synthesized by Fmoc solid-phase synthesis. The cyclopeptide and the linear peptide were linked by liquid-phase synthesis. The product depreotide was isolated and purified by high performance liquid chromatography and was confirmed by mass spectrography. Depreotide was labeled with egmTc through a direct labeling method, using HYNIC as a bifunctional chelator. Paper chromatography method was used to calculate the labeling rate, and through the comparative analysis selected the best mark conditions. The new 99mTc-HYNIC-depreotide was tested by high-performance liquid chromatography （HPLC）. The internalization and externalization rates of the new 99mTc-HYNIC-depreotide were studied in A549 cells. Furthermore, biodistribution of the radiopeptide was studied in nude mice, bearing tumors from human lung carcinoma cells SPC-A1. Results The molecular of synthesize depreotide was 1358, and the purity of it was 95.29%. The labeling efficiency of 99mTc-HYNIC-depreotide was highest at pH 6.0 and 15℃, about （70.95±0.84）%. The labeling rate of the new 99mTc-HYNIC-depreotide rose to a peak of （20.75±0.48）% at 60 minutes in A549 cells at 37℃ and decreased slightly later, while it elevated gradually during the time course at 4℃ and 25℃. The internalization rate of the new 99rnTc-HYNIC-depreotide at 37℃ increased gradually and reached the peak of 84.4% in 120 minutes, while the externalization rate of the new 99mTc-HYNIC-depreotide was always less than 20%. In mice bearing the experimental
