(99m)Tc sulfur colloid and (99m)Tc mebrofenin hepatobiliary functional liver imaging in normal and diabetic rats.

OBJECTIVES: To use (99m)Tc sulfur colloid ((99m)Tc-SC) and (99m)Tc mebrofenin ((99m)Tc-BrIDA) to study liver function in normal and diabetic rats. MATERIALS AND METHODS: Radionuclide imaging was performed on 2 groups of rats, using (99m)Tc-SC for one group and (99m)Tc-BrIDA for the other (20 rats per group) before and after induction of diabetes mellitus (DM) using streptozotocin administration (55 mg/kg i.p.). Dynamic acquisition was obtained for 1 h after the injection of 37 MBq of radiotracer. For the (99m)Tc-SC group, organ/tissue uptake was determined by drawing regions of interest (ROI) over the heart, liver, spleen and also the whole body (WB). The ratio of the ROI of each organ to the WB ROI was calculated. For (99m)Tc-BrIDA, ratios of cumulative count rates in liver, liver parenchyma, biliary tree and abdomen ROI to a WB ROI were also calculated. Statistical analysis was performed to compare the ratios of organ/tissue uptake to WB uptake before and after DM induction using the paired t test. RESULTS: (99m)Tc-SC uptake ratios (means ±SD) showed a lower liver-to-WB uptake ratio (0.75 ± 0.05) in the rats after DM induction compared to baseline (0.81 ± 0.06), while the cardiac blood pool showed higher uptake ratios in the rats after DM induction (p = 0.026). For (99m)Tc-BrIDA, there was no significant difference in radiotracer uptake ratios obtained from the rats before and after DM induction (p = 0.41). CONCLUSION: Using functional liver imaging, there was a statistically significant decrease in the liver phagocytic/reticuloendothelial system function after DM induction, as evidenced by decreased (99m)Tc-SC liver uptake and increased blood pool compared to prediabetes, while the hepatobiliary function remained unchanged after DM induction using (99m)Tc-BrIDA imaging.

Delayed gastric emptying in patients with caustic ingestion.

INTRODUCTION: Patients with caustic ingestion may develop esophageal and/or gastric cicatrization. OBJECTIVE: Scintigraphic assessment of liquid gastric emptying time in patients with caustic ingestion. MATERIALS AND METHODS: Consecutive patients with caustic-induced esophageal cicatrization attending the gastroenterology clinic of our institute were studied (patients with age >or=60 years, earlier gastric surgery, vagotomy, peptic ulcer disease, diabetes, systemic sclerosis, and those on gastrointestinal motility-altering drugs were excluded). Gastric emptying time was assessed by radionuclide scintigraphy (ingestion of 200 ml mango juice containing of 18.5 MBq 99mTc sulfur colloid after an overnight fast by static imaging in anterior and posterior projections in supine posture at 10 min intervals each for 1 h). A time-activity curve was generated and gastric half-emptying time (GET 1/2) was calculated. Results were compared with GET 1/2 values estimated for normal individuals in our laboratory (mean+/-2 SD). The emptying study protocol for normal individuals was the same as in patients. RESULTS: Twenty patients (males 10) median age 32 years, 16 with acid ingestion and four with alkali ingestion, were studied. No patient had symptoms suggestive of gastric outlet obstruction or gastroparesis. Eight patients had evidence of gastric cicatrization in the form of straightening of the lesser curvature and pulling of incisura and duodenal bulb medially and loss of parallelism between the fundus and left dome of diaphragm. Gastric distensibility was however normal in them. As compared with values for normal controls (25+/-9 min), GET 1/2 was significantly prolonged in the study group as a whole (53.2+/-27.77 min, P=0.000). No significant difference was observed between different age groups, sex, or type of caustic agent consumed. GET 1/2 differed in patients (n=10) with stricture involving lower-third of esophagus (72.2+/-27.67 min) when compared with those (n=10) who had a stricture involving upper and/or middle-third of esophagus (34.3+/-8.02 min, P=0.000). In the former, GET 1/2 was maximally prolonged in patients (n=6) with involvement of the lower esophagus and reduced stomach capacity (84.6+/-27.03 min), followed by patients (n=4) with lower esophageal involvement with normal stomach capacity (53.7+/-17.41 min), but the difference did not reach statistical significance (P=0.078). Patients (n=10) without lower esophageal involvement did not have statistically significant altered GET 1/2 compared with normal controls (P>0.05). CONCLUSION: Our results show that patients with caustic ingestion have prolonged liquid gastric emptying even in the absence of any gastric symptoms.

Sentinel lymph node biopsy for the staging of anal melanoma: report of two cases.

Primary melanoma of the anal region is a rare pathological entity and its prognosis is generally poor. The aim of this report is to demonstrate the feasibility of the sentinel lymph node (SLN) procedure with combined technique in patients with anal melanoma. We report of two cases with anal melanoma that had wide local excision of the primary lesion and was referred for further evaluation. After diagnostic metastatic work-up, SLN procedure consisted of a combination of preoperative lymphoscintigraphy with technetium-99m nanocolloid injected around the tumor, and intraoperative detection of SLN with gamma probe (combined technique) was performed. In addition, patent blue dye was injected at the periphery of the tumor to facilitate direct identification of the blue-stained lymph node. In the first case, SLN identified both inguinal and iliac lymph node basins, both of which were histologically negative on both frozen and paraffin sections. In the other case, SLN removed from the inguinal lymph node basin showed micrometastasis by paraffin section. In both cases SLN procedure with combined technique was performed sufficiently without significant complications. Consequently, we suggest that SLN procedure with combined technique is also a useful technique in malignant melanomas similar to other anal canal cancers.

Tc-99m sulfur colloid and Tc-99m tagged red blood cell methods are comparable for detecting lower gastrointestinal bleeding in clinical practice.

PURPOSE: The objective of this study was to determine whether the Tc-99m red blood cells (Tc-99m RBC) method has a true advantage over the Tc-99m sulfur colloid (Tc-99m SC) technique in a busy clinical practice for detecting and localizing lower gastrointestinal bleeding sites. METHODS: Three hundred fifty-nine consecutive gastrointestinal bleeding studies performed during the past 4 years were reviewed retrospectively. One hundred ninety-three scans were obtained with Tc-99m SC (scan duration, 30 minutes) and 138 studies were performed after the administration of Tc-99m RBC (scan duration, 1 hour). In addition, 28 examinations with Tc-99m SC were followed immediately by Tc-99m RBC scans for a duration of several hours. The results of the two methods were analyzed and the performance of the two techniques was compared. RESULTS: Among 193 scans performed using the Tc-99m SC method, 47 (24.4%) successfully identified the location of the bleeding site, whereas in 138 scans performed using Tc-99m RBC, 38 (27.5%) were successful for this purpose. In the remaining 28 scans in which the Tc-99m SC scan was followed by the Tc-99m RBC study, only 4 (14.3%) positive bleeding sites were identified after a prolonged imaging period. DISCUSSION: The theoretical advantages of the Tc-99m RBC technique compared with the Tc-99m SC method cannot be substantiated by this study. Our findings suggest that the efficacy of these two methods is nearly equal at a practical level. CONCLUSION: The simpler and cost-effective Tc-99m SC method is as efficient as the Tc-99m RBC method when the scanning time is limited to 1 hour and optimal imaging and interpretation schemes are used.

Coarse spray delivery to a localized region of the pulmonary airways for gene therapy.

Targeting adenoviral vectors for cystic fibrosis gene therapy to the human airways with minimal exposure to alveoli would avoid adverse reactions and maximize response. At present, to deliver gene therapy vectors, large volumes of fluid are instilled or nebulized as aerosols. Either approach would likely cause alveolar exposure and increases the potential for side effects. We describe a coarse spray delivery device that precisely and reproducibly delivers the viral vector to the human airways to treat a small region of the airways for clinical trials. An endoscopic washing pipe (Olympus) that can be inserted into the channel of a bronchoscope was used. To minimize the escape of the therapeutic material downstream from the site of administration, we restricted the volume delivered to <150 microl (to prevent bulk flow), and used large droplets. Their high velocity further enhanced the probability of impaction in the vicinity of the nozzle. A pneumatic dosing system (Kahnetics) was used to reproducibly deliver the spray. The droplet size distribution was determined by laser diffraction and confirmed by cascade impaction: 190-microm volume median diameter with 1% mass <10 microm. The localization of the spray was studied in hollow cast models of human airways. 99mTc-sulfur colloid was used as a radiolabeled marker for these studies. Localization of the deposited spray was determined by scintigraphy and by measuring the radioactivity exiting the terminal airways. In the lung casts the spray was localized to one or two generations over an approximately 2-cm2 area. We conclude that delivery of large droplet sprays limits exposure to a few generations and may be useful in topical gene delivery clinical trials.