Human platelets labeled with In-111 8-hydroxyquinoline: kinetics, distribution, and estimates of radiation dose

Platelets from nine normal male subjects were labeled with In-111 8-hydroxyquinoline (In-111 oxine) in the presence of plasma in either "closed" blood transfer packs or in "open" test tubes. The mean labeling efficiencies in these two systems were 27 and 53%, respectively. Mean survival time of In-111-labeled autologous platelets was 8.76 days, with a standard deviation of 1.05 according to the maximum-likelihood estimate of the gamma-function model. The initial recovery of In-111 platelets in the circulation was 57% with a standard deviation of 11%. The distribution of In-111 platelets in liver and spleen was quantitated by anterior, posterior, and transmission gamma-camera imaging. During the first 30 min, 38% of the injected dose accumulated in the spleen, 13% in the liver. No significant increase in In-111 radioactivity was observed in either of the two organs over a 3-9-day period. The bone marrow was an additional site of In-111 accumulation. The spleen was the critical organ with respect to radiation dose. The splenic dose was estimated to be 34 rad/mCi In-111 platelets, that of the liver 2.1 rad/mCi. With the injection of 100-150 microCi of In-111-labeled platelets in normal subjects, giving a splenic radiation of 5 rad, a complete 10-day survival study can be performed and uptake of In-111 in different organs can be measured quantitatively for at least 3-4 days.     

In-111-labeled leukocytes in the diagnosis of rejection and cytomegalovirus infection in renal transplant patients

Indium-111-labeled (In-111) leukocytes have been shown to be useful in the localization of inflammatory processes, including renal transplant rejection. Using previously reported labeling methods, 63 studies with this agent have been performed in 53 renal transplant patients. Indications for study included suspected rejection or cytomegalovirus (CMV) infection. Studies were performed in 33 men and 20 women, with ages ranging from 6 to 68 years. Autologous cells were normally used for labeling, although leukocytes obtained from ABO-compatible donors were used in three subjects. Rectilinear scanner and/or scintillation camera images were obtained at 24 hours after intravenous administration of 0.1 to 0.6 mCi of In-111-leukocytes. There was abnormal uptake of In-111-leukocytes in the transplanted kidney in 11 of 15 cases of rejection. In three additional cases of increased transplant uptake, CMV infection was present in two. Abnormal lung uptake was present in 13 of 14 patients with CMV infection. In four additional cases, increased lung uptake was associated with other pulmonary inflammatory disease. Increased lung activity was not seen in patients with uncomplicated transplant rejection. These results suggest that In-111-leukocyte imaging may be useful in the differential diagnosis of rejection versus CMV infection in renal transplant patients.     

Colorectal carcinoma metastases: detection with In-111-labeled monoclonal antibody CCR 086

A phase I/II clinical trial with indium-111-labeled antimucin murine monoclonal antibody (MoAb) CCR 086 was conducted. Seventeen patients with histologically proved colorectal carcinoma and known metastatic disease underwent external scintigraphy after administration of 5.5 mCi (203.5 MBq) of In-111 CCR 086 at doses of 5 and 20 mg. Of 25 known lesions, 17 were detected (sensitivity, 68%). The smallest detected lesion in the lung was 1 cm and in the liver was 1.5 cm. The serum half-life of In-111-labeled CCR 086 MoAb was approximately 64 hours. The formation of human antimouse antibody (HAMA) was detected in the serum of four of five patients who received 20 mg of MoAb. No HAMAs were detected in four patients receiving 5 mg of MoAb. No side effects were encountered. Because of effective detection of liver and lung metastases with lower doses (5-20 mg) of CCR 086 conjugated with In-111, further investigations are warranted to assess clinical and therapeutic potentials of CCR 086 in the management of colorectal cancer.     

In-111-labeled liposomes: dosimetry and tumor depiction

Neutral phospholipid vesicles (liposomes) were loaded with 0.5 mCi (18.5 MBq) indium-111 and administered to 24 patients with various types of cancer. The median diameter of the liposomes was 77 nm, and lipid dose was 0.78-6.25 mg/kg. Scans obtained 24 and 48 hours after injection of In-111 liposomes showed gradual blood clearance with homogeneous uptake in the normal liver and spleen. Dosimetric estimates for these organs were 2.3 +/- 1.1 and 2.3 +/- 1.4 rad (.02 +/- .01 Gy), respectively, with a whole-body estimate of 0.28 rad (.003 Gy). Radiation dose did not correlate with lipid dose. Total renal excretion of In-111 was less than 2% of the injected dose in all but two patients. Transient eosinophilia occurred in two patients. Tumor was seen in the scans of 22 of 24 patients (unbinded readings). In-111-labeled liposomes may enable the demonstration of suspected or unsuspected sites of tumor.     

Indium-111 labeled purified granulocytes in the diagnosis of synthetic vascular graft infection

Indium-111 labeled leukocytes have been shown to be useful in the diagnosis of synthetic vascular graft infection. To minimize the potential effects of labeled red blood cells and platelets on image interpretation, the authors prepared purified autologous granulocytes (PG) from 84 ml of blood using Volex enhanced gravity sedimentation and Ficoll-Hypaque double density centrifugation. The labeling efficiency of PG with In-111 tropolone was 90 +/- 9% (mean +/- SD). Imaging was performed 18-24 hours following injection of approximately 445 microcuries of In-111 PG in 26 patients with suspected infection of vascular grafts that had been implanted 12 days to 12 years prior to the study. In ten patients with proven graft infection, seven had positive In-111 PG scans. Ten of 11 patients without infection had negative scans. In five patients with clinically equivocal findings, scan results were positive in one, negative in one, and equivocal in three. A false-positive scan occurred in a patient with an uninfected inflammatory pseudoaneurysm of an aortic graft. These results confirm an earlier report that In-111 PG imaging is a useful technique in the diagnosis of synthetic vascular graft infection.     

Evaluation of a 3-hour indium-111 leukocyte image as a surrogate for a technetium-99m nanocolloid marrow scan in the diagnosis of orthopedic infection

OBJECTIVES: This is a retrospective study to evaluate a 3-hour In-111-labeled leukocyte image as a surrogate for a Tc-99m nanocolloid marrow scan in the investigation of suspected orthopedic infection using In-111 leukocyte scintigraphy. METHODS: Images from 51 patients who had received contemporaneous In-111-labeled leukocyte scintigraphy and Tc-99m nanocolloid marrow scintigraphy were reviewed. Initially, the 3-hour and 22-hour In-111-labeled leukocyte images were compared. Sites of abnormal uptake on the 22-hour image were correlated with the 3-hour image and were graded according to the level of concordance or discordance. One week later, the Tc-99m nanocolloid images and 22-hour In-111-labeled leukocyte images of the same patients were compared and graded for concordance or discordance. When discrepancies in grading arose between the observers, a consensus opinion was achieved after additional review of the images a week later. RESULTS: On inspection of the 22-hour In-111 leukocyte images, 93 sites of focal, potentially abnormal leukocyte accumulation were identified. When the grading system was reduced to simply "concordant" or "discordant," there was good agreement between the observers in the majority of cases, with kappa statistics 0.77 for Tc-99m nanocolloid versus 22-hour In-111-labeled leukocyte images and 0.78 for 3-hour versus 22-hour In-111-labeled leukocyte images. Using the comparison of the Tc-99m nanocolloid marrow scan and the 22-hour In-111-labeled leukocyte images to identify concordance or discordance as the "gold standard" for scintigraphic evaluation of suspected orthopedic infection, comparison of the 3-hour In-111-labeled leukocyte images with the 3-hour In-111-labeled leukocyte images gave a sensitivity of 77%, a specificity of 77%, and an accuracy of 77%. CONCLUSIONS: A 3-hour image is helpful using In-111-labeled leukocyte scintigraphy.     

Biodistribution of adult derived human liver stem cells following intraportal infusion in a 17-year-old patient with glycogenosis type 1A

IntroductionCurrent treatment of inherited liver inborn errors of metabolism in children consists in appropriate diet and drugs and, for unstable patients, final orthotopic liver transplantation. Unfortunately, liver transplantation remains not easily available because of organ shortage and imposes inherent risks and lifelong immunosuppressive therapy. Therefore alternative treatments are required. Hepatocytes transplantation and its limitations led to consider innovative alternative such as transplantation of adult derived human liver stem cells (ADLHSC). These cells present high proliferative capacity, good resistance to cryopreservation and ability to differentiate into hepatocyte-like cells displaying mature hepatocyte functions.AimBiodistribution of ADHLSC had never been assessed after infusion through the portal vein in patients. This information is required to determine the safety of the method.MethodsADHLSC were efficiently labelled with 111-Indium DTPA radiotracer and SPECT imaging was used for the acquisition of whole body imaging to document short term biodistribution of ADHLSC.ResultsFollowing infusion through the portal vein, ADHLSC diffused homogenously throughout the liver and remained strictly within the targeted organ. Images were acquired until 5 days after infusion. At that time, no signal was observed in any other organs except the liver. Urinary excretion of 111-Indium DTPA was also monitored.ConclusionFor the first time, we documented the short term biodistribution of ADHLSC within the liver after infusion through the portal vein.     

Radioimmunoimaging of lung vessels: an approach using indium-111-labeled monoclonal antibody to angiotensin-converting enzyme

A murine monoclonal antibody against human angiotensin-converting enzyme was radiolabeled with 111In via diethylenetriaminepentaacetic acid without substantial loss of antigen-binding capacity. This monoclonal antibody designated 9B9 cross-reacted with rat and monkey angiotensin-converting enzyme. Indium-111-labeled 9B9 selectively accumulated 10-20 times greater in the lung than in blood or other organs following intravenous administration in rats. Kinetics of lung accumulation and blood clearance were studied for 111In-9B9-antibody and compared to that of 125I-labeled 9B9 in rat. Highly specific accumulation of 111In-9B9-antibody in the lung of Macaca Rhesus monkeys after intravenous injection was monitored by gamma-imaging. Images of 111In-labeled antibody 9B9 biodistribution in monkey lung noticeably differ from the images of biodistribution of 99mTc-labeled albumin microspheres. This difference may provide information concerning the state of the endothelium of lung capillaries, which is different from the blood flow characteristics determined with routine microsphere technique.     

Postoperative bone marrow alterations: potential pitfalls in the diagnosis of osteomyelitis with In-111-labeled leukocyte scintigraphy.

Scintigraphy was used after injection of technetium-99m methylene diphosphonate (MDP) and indium-111-labeled white blood cells (WBCs) to assess for the presence of osteomyelitis in 97 patients who had undergone prior surgical procedures. Thirty-four patients with abnormal In-111-labeled WBC patterns underwent restudy with Tc-99m albumin colloid (AC). Scintigraphic findings were considered positive for osteomyelitis whenever localization of In-111-labeled WBCs exceeded Tc-99m AC activity in extent or focal intensity (discordant pattern). Ten of 12 patients with culture-proved osteomyelitis had discordant patterns; two had false-negative (concordant) patterns. The cases of 20 of 22 patients without infection who were considered to have osteomyelitis on the basis of patterns of In-111-labeled WBCs and Tc-99m MDP were reclassified correctly on the basis of concordant patterns of In-111-labeled WBCs and Tc-99m AC. Radiocolloid images improved the overall scintigraphic specificity for osteomyelitis from 59% without bone marrow imaging to 92%; sensitivity decreased from 94% to 88%.     

Biodistribution of radiolabeled lymphocytes

Factors that might affect the biodistribution and clinical utility of radiolabeled lymphocytes were evaluated in experimental animals. Indium-111 (In-111) labeled lymphocytes (10(7)-10(9) syngeneic or allogeneic cells; 1-10 microCi [.037-.37 MBq]/10(8) cells) obtained from peripheral blood, lymph node, or spleen were found in significant amounts in the lymphoid tissues of Lewis rats as early as 3 hours after infusion. A progressive increase in nodal activity with concomitant fall of activity in other organs followed, indicating active recirculation of the lymphocytes. However, In-111 labeled thymocytes or xenogeneic lymphocytes failed to accumulate in lymphoid tissue. In vitro irradiation of the In-111 labeled lymphocytes (100-400 rads [1-4 Gy]) before in vivo administration and increase of the In-111 to 40 microCi [1.48 MBq]/10(8) lymphocytes resulted in no detectable lymphocyte recirculation and/or reduced localization in lymphoid tissue. Splenectomized animals and those sensitized to an organ allograft before cell infusion showed increased activity in their bone marrow. These results suggest that the source of the injected cells, cell irradiation dose level, and host sensitization should be considered when radiolabeled lymphocytes are being prepared for use in clinical diagnosis and therapy.     

Pharmacokinetics and biodistribution of 111In- and 177Lu-labeled J591 antibody specific for prostate-specific membrane antigen: prediction of 90Y-J591 radiation dosimetry based on 111In or 177Lu?

111In-Labeled antibodies and peptides have been routinely used as chemical and biologic surrogates for 90Y-labeled therapeutic agents. However, recent studies have shown that there are significant differences in biodistribution between 111In- and 90Y-labeled agents. Yttrium and lutetium metals favor the +3 oxidation state, similar to indium, but there are minor differences in the solution and coordination chemistries among these metals. These 3 metals, however, form strong complexes with the macrocyclic chelator, 1,4,7,10-tetraazacyclododecane-N,N',N',N'-tetraacetic acid (DOTA). We, therefore, compared the pharmacokinetics and biodistribution of 111In- and 177Lu-labeled J591 antibody. The radiation dosimetry of 90Y-J591 was estimated based on both 111In and 177Lu data to validate the usage of 111In as a chemical and biologic surrogate for 90Y. METHODS: J591 is a deimmunized monoclonal antibody with specificity for the extracellular domain of prostate-specific membrane antigen. In patients with prostate cancer, phase I dose-escalation studies were conducted with 90Y-J591 (n = 29) and 177Lu-J591 (n = 25). Each patient had pharmacokinetics and imaging studies with 111In-J591 (185 MBq/20 mg) over a period of 1 wk and before treatment with 90Y-J591 antibody. In the 177Lu trial, the pharmacokinetics and imaging studies were performed after treatment with the 177Lu-J591 dose (370-2,590 MBq/m2/10 mg/m2) over a 2-wk period after treatment. RESULTS: Blood and urinary pharmacokinetics were similar for both tracers. Based on biexponential decay, the terminal half-life was 44 +/- 15 h for both tracers. In addition, the total-body retention of radioactivity over a 7-d period was also similar between the 2 isotopes. The percentage uptake in liver was about 20% greater with 111In than with 177Lu. Radiation dosimetry estimates for 90Y-J591 calculated on the basis of 111In or 177Lu data were mostly similar and showed that liver is the critical organ, followed by spleen and kidney. Based on blood radioactivity, the radiation dose (mGy/MBq) to the bone marrow was 3 times higher with 90Y (0.91 +/- 0.43) compared with that with 177Lu (0.32 +/- 0.10). CONCLUSION: 111In- and 177Lu-labeled J591 antibodies have similar plasma and whole-body clearance kinetics. The net retention of 111In activity by lung, liver, and spleen is slightly higher compared with that with 177Lu. These results justify using 111In as a chemical and biologic surrogate for 90Y. However, the radiation dose to the liver may be overestimated by about 25% based on 111In data. In addition, the data also suggest that 177Lu may be a potential alternative for estimating the pharmacokinetics and biodistribution of 90Y-labeled radiopharmaceuticals.     

Significance of alteration in biodistribution of labeled lymphocytes exposed to stannous ion

The biodistribution patterns of 99mTc (99mTc-lymph) and 111In-lymphocytes with [111In-(Sn)-lymph] or without (111In-lymph) stannous ion treatment was compared in Lewis rats. Syngeneic lymphocytes were labeled with either 125 microCi (4.63 MBq) 99mTc or 5 microCi (185 kBq) 111In per 2 x 10(7) cells. Mean labeling efficiency for 99mTc and 111In was 68.61% +/- 3.90% (SEM) and 87.22% +/- 2.01% (SEM) respectively. 99mTc-lymph (n = 4), 111In-lymph (n = 6) and 111In-(Sn)-lymph (n = 6) rats received 2 x 10(7) cells and were killed 18 h later. While 99mTc-lymph demonstrated significantly less localization in spleen, lymph nodes, and blood (P(F) less than 0.01) as compared with 111In-lymph, 111In-(Sn)lymph also demonstrated a significant difference (P[F]= 0.0001) in lymph node accumulation when compared to 111In-lymph. As the activity levels utilized are not associated with cell radiation damage, these alterations in biodistribution do not reflect viability or chromosomal damage, but appear related to stannous ion exposure.     

Similarities and differences in 111In- and 90Y-labeled 1B4M-DTPA antiTac monoclonal antibody distribution.

Monoclonal antibodies (MoAb) labeled with 90Y are being used for radioimmunotherapy. Because 90Y is a beta emitter, quantitative information from imaging is suboptimal. With the concept of a "matched pair" of isotopes, 111In is used as a surrogate markerfor90Y. We evaluated the differences in biodistribution between 111In- and 90Y-labeled murine antiTac MoAb directed against the IL-2Ralpha receptor. METHODS: The antiTac was conjugated to the 2-(4-isothiocyanatobenzyl)-6-methyl-diethylenetriamine pentaacetic acid (1B4M-DTPA, also known as MX-DTPA). Nine patients with adult T-cell leukemia were treated. Patients received approximately 185 MBq (5 mCi) 111In-labeled antiTac for imaging and 185-555 MBq (5-15 mCi) 90Y-labeled antiTac for therapy. The immunoreactivity of 111In-labeled antiTac was 90%+/-6%, whereas for 90Y-labeled antiTac, it was 74%+/-12%. RESULTS: The differences in blood and plasma kinetics of the two isotopes were small. The area undemeath the blood radioactivity curve was 1.91 percentage+/-0.58 percentage injected dose (%ID) x h/mL for 111In and 1.86%+/-0.64 %ID x h/mL for 90Y. Urinary excretion of 90Y was significantly greater than that of 111In in the first 24 h (P = 0.001), but later, the excretion of 111In was significantly greater (P = 0.001 to P = 0.04). Core biopsies of bone marrow showed a mean of 0.0029+/-0.0012 %ID/g for 111In, whereas the 90Y concentration was 0.0049+/-0.0021 %ID/g. Analyses of activity bound to circulating cells showed concentrations of 500-30,000 molecules of antiTac per cell. When cell-bound activity was corrected for immunoreactive fraction, the ratio of 111In to 90Y in circulating cells was 1.11+/-0.17. Three biopsies of tumor-involved skin showed ratios of 111In to 90Y of 0.7, 0.9 and 1.1. CONCLUSION: This study shows that differences typically ranging from 10% to 15% exist in the biodistribution between 111In- and 90Y-labeled antiTac. Thus, it appears that 111In can be used as a surrogate marker for 90Y when labeling antiTac with the 1 B4M chelate, although underestimates of the bone marrow radiation dose should be anticipated.     

Characterization of the asialoglycoprotein receptor under hypoxic conditions in primary cultured rat hepatocytes.

Hepatic ischemia/reperfusion injury occurs in numerous clinical situations including liver transplantation and hepatic resection. Therefore, accurate functional assessment of hepatocytes and prevention of ischemia/reperfusion injury to hepatocytes would be important. (99m)Tc-Galactosyl-human serum albumin is a liver scintigraphic agent that binds to asialoglycoprotein receptors (ASGP-R) on hepatocytes. We determined the number of ASGP-R during hypoxic conditions in primary cultured rat hepatocytes. METHODS: We used 3 durations of hypoxia (1, 2, and 3 h) for the cultured rat hepatocytes. The control incubation was performed under normoxic conditions (humidified 5% CO(2) in air) for the entire experiment. The maximal binding of (99m)Tc-galactosyl-human serum albumin (Bmax) to the hepatocytes (plasma membrane and endocytosis) and ketone body ratio (KBR) in the medium were estimated. RESULTS: The Bmax to hepatocytes and the KBR significantly decreased with time under the 3 different hypoxic conditions, whereas the cell counts of the hepatocytes did not decrease. Three hours after reoxygenation, the Bmax and KBR values that were decreased in the first 2 h of hypoxia reversed to control levels, but those Bmax and KBR values that were decreased after 3 h of hypoxia were irreversible. CONCLUSION: We conclude that the decrease in the number of ASGP-R per hepatocyte appears to be more significant than the decrease in the number of hepatocytes. Therefore, measurement of ASGP-R may provide an accurate assessment of hepatic function in the clinical setting of hepatic injury and recovery.     

Neutrophil labeling with indium-111: tropolone vs. oxine

This study was undertaken to compare tropolone with oxine (8-hydroxy-quinoline) for labeling human neutrophils with In-111. Exposure of neutrophils to tropolone at concentrations required for efficient labeling resulted in a marked impairment of chemotaxis. In contrast, no impairment of neutrophil chemotaxis was observed using In-111 oxine. Labeling efficiencies obtained with In-111 tropolone under optimal conditions were consistently less than those obtained with In-111 oxine. We evaluated cells labeled by the two methods using chemotaxis radioassay to assess the chemotatic potential of labeled cells. The results led to the conclusion that the oxine technique is preferable to tropolone for labeling human neutrophils with In-111.     

Intense accumulation of indium-111 leukocytes in peritonitis carcinomatosa

In order to detect the infectious foci in a case of terminal recurrent cancer of the sigmoid colon with intense inflammation, In-111 oxine leukocyte scintigraphy was performed. Leukocytes labeled with In-111 oxine quickly localized within the region of peritonitis carcinomatosa and could be imaged after 4 hours. With time, high activity appeared in this area. And 48 hours after injection, the large intestine was clearly seen. However, no activity was seen in the main recurrent tumor. This suggested that the labeled leukocytes had accumulated in regions of inflammation rather than in malignant tissue. When performing In-111 leukocyte scintigraphy for diseases in which tumor cells and inflammation are mixed, distinguishing the two components is particularly important, and time-sequential scanning is very useful.     

Indium-111-labeled human polymorphonuclear leukocytes: viability, random migration, chemotaxis, bacterial capacity, and ultrastructure.

Human polymorphonuclear leukocytes (PMNs) were labeled with indium-111 oxine in ethanol, and the effects of the labeling procedure, radioactivity, and concentrations of oxine and ethanol on PMN function and structure were studied in vitro. The standard labeling procedure did not alter the viability, random migration, chemotaxis, bactericidal capacity, or the ultrastructure of PMNs. Exposure to higher doses of radioactivity, or to higher concentrations of ethanol, had no appreciable effects on random migration and chemotaxis of PMNs. A dose-dependent reduction in their random migration and chemotaxis was observed when higher concentrations of oxine were used. These results indicate that In-111-labeled PMNs are structurally intact and have normal in vitro locomotion and bactericidal activity. Indium-111-labeled PMNs should be suitable for studying the kinetics and distribution of these cells in health and disease.     

Pharmacokinetics of 111In- and 125I-labeled antiTac single-chain Fv recombinant immunotoxin.

The use of immunotoxins for cancer therapy is an attractive strategy that exploits the targeting specificity of monoclonal antibodies and their fragments as well as the exquisite toxicity of the toxins. However, few studies of immunotoxins have evaluated their biodistribution in vivo. Previous studies have used 125I for tracing immunotoxin biodistribution in mice. Because the immunotoxin works only when it is internalized and because of known problems with quick dehalogenation after internalization of antibodies, we decided to use 111In, which has greater intracellular retention than iodine. METHODS: To trace the in vivo pharmacokinetics of the immunotoxin in mice, we labeled the antiTac(Fv)-PE38 with 111ln and compared it with 125I-labeled antiTac(Fv)-PE38. We successfully labeled antiTac(Fv)-PE38 with 111In at up to 2.96 GBq/mg. A 3- to 4-fold decrease in cytotoxicity was observed for both radiolabeled preparations. We evaluated the internalization of 111In- and 125I-labeled antiTac(Fv)PE38 into ATAC4 cells (Tac-positive) as well as their biodistribution and pharmacokinetics in vivo in mice. In addition, some mice receiving these reagents were co-infused with 30 mg L-lysine to inhibit renal accumulation. RESULTS: Significantly more 111In- than 125I-labeled antiTac(Fv)-PE38 accumulated in the ATAC4 cells (20% versus 5% of initial surface-bound radioactivity; P < 0.001). In vivo, significantly more 111In- than 125I-labeled antiTac(Fv)-PE38 accumulated in the kidney (119 versus 31 percentage injected dose per gram [%ID/g]; P < 0.001). The tumor accumulation of 111In-labeled antiTac(Fv)-PE38 at 96 h was 13-fold greater than that of 125I-labeled antiTac(Fv)-PE38 (1.4 versus 0.1 %ID/g; P < 0.001). No antiTac(Fv)-PE38 was excreted into the urine in its intact form unless lysine was co-infused. Co-injected lysine reduced the renal accumulation of 111In-labeled antiTac(Fv)-PE38 by 62%. CONCLUSION: We evaluated the biodistribution, pharmacokinetics, and catabolism of 111In-labeled antiTac(Fv)-PE38 and found that it differed from 125I-labeled antiTac(Fv)PE38. These studies suggest that 111In-labeled antiTac(Fv)-PE38 can be used to trace the fate of antiTac(Fv)-PE38 in humans.     

多层面螺旋CT对肝移植术后肝动脉狭窄肝灌注的研究

目的　利用动态单层CT扫描对原位肝移植术后肝动脉狭窄肝灌注与未行肝移植、无肝脏病变者进行比较。资料与方法　对 30例肝移植术后肝动脉狭窄患者选取肝门 (包括肝、门静脉、主动脉和脾 )层面行动态单层CT扫描。高压注射器经肘静脉注射非离子型对比剂欧乃派克 4 0ml,流率 3ml/s,注射对比剂时即进行扫描 ,每间隔1s扫 1层 ,共扫描 35层。通过每一层面选定的ROI作CT值测量 ,绘制出时间 密度曲线 ,从而计算出相应灌注值并与未行肝移植、无肝脏病变者进行对照。结果　肝移植术后肝动脉狭窄 <5 0 %组 ,肝动脉灌注 (t=0 .5 ,P >0 .0 5 )、门静脉灌注 (t=1 ,P >0 .0 5 )与对照组间无显著差异 ;肝动脉狭窄≥ 5 0 % ,肝动脉灌注与对照组存在差异 (t =2 .1 4 ,P <0 .0 5 ) ,低于对照组 ,门静脉灌注与对照组有差异 (t=2 .6 3,P <0 .0 5 ) ,高于对照组。结论　肝移植术后肝动脉狭窄≥ 5 0 % ,肝动脉灌注降低而门静脉灌注升高。动态单层CT扫描对于评价肝移植术后肝脏灌注是有帮助的     

Indium-111 pentetreotide imaging of carcinoid tumor of the thymus

INTRODUCTION: Carcinoid tumors are relatively rare and can occur in the thorax, abdomen, or pelvis. Indium-111 pentetreotide scanning is useful for the identification of these tumors. In this report, we present imaging findings and discussion pertaining to a 43-year-old man who presented with Cushing's syndrome resulting from a thymic carcinoid tumor. The imaging is of interest because there is not only marked uptake of In-111 pentetreotide in the thymic carcinoid tumor, but also within the adrenal glands attributable to elevated tumor-derived ACTH. METHOD: Planar and single-photon emission computed tomography (SPECT) images of the chest and abdomen were obtained 15 minutes after the injection of 6.6 mCi of In-111 pentetreotide. Further planar and SPECT images were obtained approximately 4 and 24 hours after injection of the radiopharmaceutical. Correlation of In-111 pentetreotide SPECT was made with laboratory results and CT evaluation of the chest and abdomen. RESULTS: Initial clinical workup for Cushing's syndrome included a contrast-enhanced brain magnetic resonance image that showed a small pituitary lesion thought to represent a microadenoma. Normal inferior petrosal venous sinus sampling for ACTH suggested there was an ectopic ACTH source. Subsequent CT of the chest identified a 3 x 3-cm enhancing mediastinal mass. Avid uptake within the mass on In-111 pentetreotide images suggested that the underlying cause of Cushing's syndrome was ACTH production from a thymic carcinoid. Increased uptake of In-111 pentetreotide was also noted within hyperplastic adrenal glands. Surgical resection and histologic evaluation established the diagnosis of a moderately differentiated thymic carcinoid tumor. CONCLUSION: This case illustrates the complementary ability of In-111 pentetreotide planar and SPECT imaging and CT to diagnose an ACTH-producing thymic carcinoid tumor leading to adrenal hyperplasia and Cushing's syndrome.