Tc-99m HMPAO SPECT analysis of neuroleptic effects on regional brain function

This report describes a new approach to the evaluation of neuroleptic effects on regional brain function. Using Tc-99m HMPAO SPECT imaging, consecutive brain perfusion studies before and after acute haloperidol administration were performed on three schizophrenic patients and two normal volunteers. The antipsychotic drug ameliorated the hypoactivity in the frontal lobe and suppressed the hyperactivity in the temporo-occipito-parietal lobe selectively in the dominant hemisphere in the schizophrenic patients. It did not exert a significant influence on the brain perfusion pattern in normal volunteers. This nuclear medicine technique seems to be useful for the evaluation of drug effects in psychiatric diseases.

[The diagnostic value of In-111 transferrin imaging in protein-losing gastroenteropathy]

The diagnostic value of In-111 transferrin abdominal imaging was studied in 17 patients with clinical suspicion of protein-losing gastroenteropathy, compared to that of alpha-1-antitrypsin fecal clearance test. The presence or absence of gastrointestinal protein-loss was finally decided based on the result of alpha-1-antitrypsin fecal clearance test (normal range, less than 13 ml/day) or of protein content measurement on the gastric juice (normal range, less than 71 mg/dl). In-111 transferrin was labeled in vitro. After intravenous administration, serial anterior abdominal images were obtained. All seven patients with a value equal to or more than 20 ml/day on the alpha-1-antitrypsin clearance test and two out of ten patients with a value less than 20 ml/day showed definite intestinal activity demonstrating protein-loss, and the loss-site was estimated by observing the movement of radiotracer within the bowel lumen. The patients with severe protein-loss showed the intestinal activity on the early image. In the patients with milder protein-loss, on the other hand, the activity was noted on the later image. All two patients with positive In-111 transferrin imaging and negative alpha-1-antitrypsin test were associated with protein-losing gastropathy, where a value of alpha-1-antitrypsin clearance was not increased because of denatured alpha-1-antitrypsin by acidic gastric juice and pepsin. These results suggest that In-111 transferrin abdominal imaging can be more useful for the diagnosis of protein-losing gastroenteropathy, because of its capabilities to evaluate the patients with gastropathy as well as to estimate the loss-site.

Evaluation of inferior mesenteric vein blood flow circulation with per-rectal administration of thallium-201 and technetium-99m pertechnetate

We administered both per-rectal thallium-201 (201Tl) and technetium-99m pertechnetate (99mTc) to patients with liver diseases in order to understand the abnormalities of inferior mesenteric vein (IMV) blood flow circulation. As 201Tl heart-to-liver uptake ratio (H:L), reflecting the degree of portal-systemic shuntings (PSS), increased, the visualization of IMV in general became poor on 99mTc scintigrams. 201Tl H:L in the group with no visualization of IMV on 99mTc scintigrams was significantly higher than in the group with clear visualization of IMV (p less than 0.001). However, there were patients who showed IMV visualization among those with high 201Tl H:L. In these patients, it was considered that IMV blood flowed in the normograde direction, escaping mainly through PSS at the upper part of the portal system, and resulting in elevated H:L. In the patients without IMV visualization, IMV blood flowed in the retrograde direction, escaping mainly through collaterals at the lower part of IMV. Inferior vena cava (IVC) was visualized on 99mTc scintigrams in some patients without IMV visualization, indicating the presence of collaterals from the distal part of IMV to IVC. Per-rectal studies using these two radiotracers can afford us useful informations on the abnormalities of IMV blood flow hemodynamics in patients with liver diseases.

[The evaluation of split renal function in the experimentally induced transient renal vein obstruction]

The split renal function was measured in order to evaluate the alteration of renal function secondary from transient renal vein obstruction. Three microcuries of I-131 Hippuran and 7 microCi of Tc-99m DTPA were injected into the femoral vein of adult male rats 30 min, 3 hr, 6 hr, 2 days and 1 week after the renal vein obstruction for 30 min. Blood samples were taken from the tail vein 5, 10, 15, 20 and 30 min after injection. Immediately after taking blood sample at 30 min, both kidneys and urinary bladder with ureters were taken. The radioactivities of Tc-99m and I-131 of these samples were measured respectively using a well type scintillation counter at the energy ranges of 140 KeV +/- 25% and 360 KeV +/- 25%. In the obstructed side, the blood clearances of I-131 Hippuran (ERPF) and Tc-99m DTPA (GFR) were decreased at 30 min and 6 hr after the release of left renal vein obstruction. Therefore the filtration fraction was not significantly changed. In conclusion, the single study using either Tc-99m DTPA or I-131 Hippuran may be enough to evaluate the alteration of split renal function in a model of renal vein obstruction, although the combined study using both agents is more preferable.

Indium-111 transferrin imaging for the diagnosis of protein-losing enteropathy

For assessment of gastrointestinal protein loss, seven patients suspected of having protein-losing enteropathy were studied by gamma camera imaging using in-111 transferrin. Four patients with a value equal to or more than 20 ml/day on the alpha-antitrypsin clearance test or a high protein content on the gastric juice showed definite intestinal activity on an early image, demonstrating protein loss. The loss site could be determined by observing the movement of radiotracer within the bowel lumen on the subsequent images. The three patients with a value of less than 20 ml/day in the test showed no obvious intestinal activity throughout the study. Therefore, in-111 transferrin abdominal imaging appears to be useful for determining the loss site as well as for establishing the rapid diagnosis of protein-losing enteropathy.

Thallium-201 single photon emission computed tomography in the evaluation of suspected lung cancer

Thallium-201 SPECT was performed in 30 patients with suspected lung cancer. Both early and delayed scans demonstrated abnormal accumulation in all of 23 malignant pulmonary lesions including 21 lung cancer and in two of seven benign conditions. There were significant differences in delayed ratio (uptake ratio of the lesion to the normal lung on delayed scan) and retention index (degree of retention in the lesion) between lung cancer and benign conditions, respectively (p less than 0.01, p less than 0.05). The delayed ratio and retention index revealed that adenocarcinoma showed higher 201Tl accumulation than squamous cell carcinoma and small cell carcinoma (p less than 0.05) and 201Tl clearance in squamous cell carcinoma was faster than in the other two (p less than 0.05). Mediastinal involvement was detected in five of seven patients on delayed scans. The smallest lesion depicted was 1.5 cm in diameter. Two false negatives had small metastases less than 1.0 cm in diameter. This method seems to be useful to detect lung cancer, to differentiate malignant from benign lesions, and to evaluate mediastinal involvement from lung cancer.

[Subcellular kinetics of In-111 monoclonal antibody in the liver]

To evaluate the mechanism for prolonged retention of In-111 monoclonal antibody (MoAb) by the liver, we investigated the subcellular kinetics of the In-111 225.28S, an antimelanoma IgG2a. Forty microCi/10 micrograms of the In-111 MoAb was injected IV into groups of SD rats. The liver was excised at 3, 8, 17, 24, 48 and 72 hr and homogenized with 0.25 M sucrose containing 0.01 M Tris-HCl buffer (pH 7.6). Subcellular fractionation was carried out by 3-step (ultra-)centrifugation. The radioactivity of each fraction including nuclear, mitochondrial (lysosomal), microsomal and supernatant fraction was measured and expressed as a percentage of the total radioactivity of all the fractions. Moreover, the supernatant fraction was assessed by size exclusion HPLC. The supernatant was a predominant fraction of the In-111 radioactivity, 61% at 3 hr, and was decreased with time, 21% at 72 hr (p less than 0.01), while the activity in the mitochondrial fraction continued to increase from 11% to 44%. As compared to these two fractions, the nuclear and microsomal radioactivities were relatively constant, 10-25%, throughout the study. The HPLC analysis revealed that the supernatant In-111 activity at early time points was mainly eluted with an intact IgG and thereafter this major peak activity was reduced with associated activity peaks found in smaller moiety fractions. To compare the In-111 MoAb with the iodine labeled MoAb, we also investigated the subcellular kinetics of the I-125 MoAb in the same manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Radioimmunoscintigraphy of xenografted human thyroid carcinoma

We developed monoclonal antibodies against human thyroid cancer-associated antigen by fusing mouse myeloma cells with mouse spleen cells immunized by insoluble fraction of homogenized thyroid papillary carcinoma cells. One monoclonal antibody (KTC-3, IgM) was selected to evaluate basic usefulness for radioimmunoscintigraphy in xenografted human thyroid carcinoma. KTC-3 was labeled with 131I by Iodogen method of 20 to 1 Iodogen to IgM molar ratio. It was also labeled with 111In by cyclic DTPA anhydride method of 20 to 1 DTPA to IgM molar ratio. The labeling efficiency and specific activity for 131I labeling were 16.5% and 0.66 mCi/mg IgM respectively, and those for 111In labeling were 12.7% and 1.6 mCi/mg IgM. Imaging and biodistribution of labeled KTC-3 were evaluated in nude mice bearing thyroid anaplastic carcinoma (THC-5-JCK). The tumors were well visualized 3 and 5 days after injection of 131I KTC-3. Tumor uptake of 131I KTC-3 on day 7 was 0.52 +/- 0.27% ID/g and tumor to blood ratio was 1.98 +/- 0.76 (n = 6). Those of 111In KTC-3 were 0.88 +/- 0.09% ID/g and 5.51 +/- 3.36 (n = 6). In conclusion, KTC-3 is promising for radioimmunoscintigraphy of thyroid cancer.