[Affinity of the elements in group VI of the periodic table to tumors and organs]

In order to investigate the tumor affinity radioisotopes, chromium (51Cr), molybdenum (99Mo), tungsten (181W), selenium (75Se) and tellurium (127mTe)--the elements of group VI in the periodic table--were examined, using the rats which were subcutaneously transplanted with Yoshida sarcoma. Seven preprarations, sodium chromate (Na251CrO4), chromium chloride (51CrCl3), normal ammonium molybdate ((NH4)299MoO7), sodium tungstate (Na2181WO4), sodium selenate (Na275SeO4), sodium selenite (Na275SeO3) and tellurous acid (H2127mTeO3) were injected intravenously to each group of tumor bearing rats. These rats were sacrificed at various periods after injection of each preparation: 3 hours, 24 hours and 48 hours in all preparations. The radioactivities of the tumor, blood, muscle, liver, kidney and spleen were measured by a well-type scintillation counter, and retention values (in every tissue including the tumor) were calculated in percent of administered dose per g-tissue weight. All of seven preparations did not have any affinity for malignant tumor. Na251CrO4 and H2127mTeO3 had some affinity for the kidneys, and Na275SeO3 had some affinity for the liver. Na2181WO4 and (NH4)299MoO4 disappeared very rapidly from the blood and soft tissue, and about seventy-five percent of radioactivity was excreted in urine within first 3 hours.

[Study on tumor affinity of technetium-99m-labeled radiopharmaceuticals. (2) 99mTc-Sn-diphosphonate (99mTc-EHDP), 99mTc-Sn-dimercaptosuccinic acid (99mTc-DMSA), and 99mTc-Sn-diethyl stilbestrol diphosphate (99mTc-DSDP)]

The authors have examined the tumor affinity of various 99mTc-labelled radiopharmaceuticals to Ehrlich's tumor for the purpose of delineating positively human malignant neoplasm. This paper includes biologic distributions of 99mTc-Sn-diphosphonate (99mTc-EHDP), 99mTc-Sn-dimercaptosuccinic acid (99mTc-DMSA) and 99mTc-Sn-diethyl stilbestrol diphosphate (99mTc-DSDP, 99mTc-Honvan) as the second report on the tumor affinity to the Ehrlich-bearing mice. (a) Tumor concentration of 99mTc-EHDP was lowest and the positive delineation of implanted tumor with 99mTc-EHDP was poorest in sequential images, though the active accumulation to some soft tissue maglinant neoplasms, the breast cancer and the thyroid cancer, has been reported. (b) Tumor concentration and tumor to blood ratio of 99mTc-DMSA were not so high on the contrary of our expectation that 197Hg-DMSA may show the high tumor concentration and the high tumor to blood ratio like 197Hg chlormerodrin as same renal scanning radiopharmaceuticals. (c) Tumor concentration of 99mTc-DSDP was highest. Tumor to blood concentration ratio, however, was lower than that of the above mentioned radiopharmaceuticals but tumor to liver ratio and/or tumor to lung ratio was over 1.0 at the earlier time. Biologic distribution of 99mTc-DSDP was similar to that of 32P labeled DSDP and then it is presumed that 99mTc is labeled at phosphate ester of DSDP which is dephospholytated immediately by phospholylase in vivo following the intravenous injection. Therefore, it may be assumed that the accumulation mechanism of 99mTc-DSDP to Ehrlich's tumor is related to the phospholylase activity in neoplasms but is not known precisely.

[Advantages, disadvantages and selection methods of thyroxine measurement--comparison of CPBA and RIA]

Although recent progress in radioimmunoassay (RIA) permitted direct RIA for thyroxine (T4), there appeared few reports evaluating clinical applicability of T4 RIA as routine method. The authors evaluated advantage, disadvantage of methods for T4 measurement in comparison between CPBA (competitive protein binding analysis) and RIA, and tried to discuss about selection of methods for T4 measurement. Res-O-Mat T4 was chosen as CPBA, and RIAMAT-T4(St) and T4-RIAKIT(Sp) were chosen as RIAs. Detailed descriptions about both RIA methods appeared elsewhere [2, 3]. From the basic experiments, reproducibility of CPBA, St and Sp within assay were 5.8% (C.V.), 4.0% (C.V.), and 8.5%(C.V.) respectively, and mean recovery rates were 92.2%, 100.7% and 96.1% respectively. T4 value measured by both RIAs correlated well with CPBA, and St showed slightly lower value and Sp showed slightly higher value than CPBA. The normal ranges for RIAs were 3.7-11.7 microng% (St) and 4.6-15.2 microng% (Sp). Diagnostic accuracy for hyperthyroid state were 83.3% (CPBA), 85.7%(St) and 69.2% (Sp), and for euthyroid state were 92.0% (CPBA), 98.8% (St) and 95.7% (Sp). The diagnostic accuracy for hypothyroid state in three methods were lowest. From the economical point of view, cost performance, time performance and total time for single assay were analysed and mathematical equations were obtained from actual assay by each methods. When the number of samples per single assay was less than 10, CPBA was most economic in terms of cost and time performance and total time required. In the assay of more than 20 samples, RIAs were efficient in each point of views. In the point of view of sample volumes required, RIAs were most promising. The authors concluded that guides for selection of methods in T4 assay were as follows: A) CPBA was most efficient in local use especially when less than 10 samples were frequently to be assayed. B) RIAs were efficient in batch processing more than 20 samples, especially in automated laboratories.

[Study on tumor affinity of technetium-99m-labeled radiopharmaceuticals. (1) 99mTc-pertechnetate, 99mTc-human serum albumin, and 99mTc-trasylol]

This paper describes biologic distributions, sequential images and macroautoradiograms of 99mTcO4 (pertechnetate), 99mTc-Sn-HSA (human serum albumin) and 99mTc-Sn-TSL (trasylol) in tumor-bearing mice as the first report on tumor affinity of 99mTc-labeled radiopharmaceutical. (1) Maximum tumor concentration (% administered dose/g of tissue weight) of 99mTcO4, 99mTc-HSA and 99mTc-TSL in Ehrlich's tumor-bearing mice resulted in 2.03+/-0.57 at 1 hr, 4.02+/-0.19 at 3 hr and 1.97+/-0.31 at 1 hr respectively. (2) However, tumor to blood concentration ratio of 99mTc-HSA was lowest among them. (3) The corrected tumor accumulation (% 100g dose/g of tissue wt.=% dose/% body weight) of 99mTc-TSL to Ehrlich's tumor in mouse was not different from that of Yoshida's sarcoma in rat, on the contrary to our expectation that the tumor concentration of 99mTc-TSL in them might be different due to differency of the tissue fibrinolytic activity between the respective tumors. (4) Sequential images of the implanted tumor in mouse was best positively delineated with 99mTc-HSA. (5) Macroautoradiograms of Ehrlich's tumor with 99mTcO4, 99mTc-HSA and 99mTc-TSL demonstrated the following findings: all of them were not only accumulated markedly into the tumor cells which were shown as basophilic tissue with Hämatoxylin-Eosin staining but also accumulated around the tumor tissue and on the interstitial tissue which were stained as eosinophilic tissue with the above same staining.

Whole body transmission-emission scanning with whole body camera

Whole body transmission-emission scanning was carried out using a whole body camera. A disk source 30 cm in diameter filled with 99mTc was used for transmission scanning. Correct interpretation of emission scanning requires accurate anatomical orientation of the images. The value of whole body transmission-emission scanning is emphasized.

Clinical evaluation of tumor scanning with 169-Yb-citrate

169-Yb-citrate was used as the tumor-scanning agent in 360 patients with malignant tumors and in 55 others with benign lesions and the results compared with 67-Ga-citrate studies in other series. In malignant tumors, the overall positive detection rate for ytterbium was 65.3%; in benign lesions, the false-positive rate was 29.1%. Good results were obtained in the extremities, head and neck, and pelvic area. Of all tumors visualized, squamous cell carcinoma was detected most effectively (77.5%). 169-Yb-citrate has a long shelf life, photon peaks of 178 and 198 kev, clears from the blood more rapidly than 67-Ga-citrate and has an extremely low soft-tissue background uptake. Its main disadvantage is its high radiation dose: 1.74 R/500 muCi whole-body and 5.77 R to the bone.

Brain scan in cerebrovascular "Moyamoya" disease

Brain scans were abnormal in 2 of 6 patients with cerebral "Moyamoya" disease. The spatial and temporal scan patterns were analogous to those described in conventional cerebral infarction. Cerebral infarction due to emboli resulting from mural thrombi may explain the uptake of radioisotope. None of the scans was abnormal in 4 adult patients in which the disease was complicated by subarachnoid hemorrhage.

Comparison of alpha1 fetoprotein radioimmunoassay method and liver scanning for detecting primary hepatic cell carcinoma

Alpha1 (alpha 1) fetoprotein (AFP) radioimmunoassay method was routinely used in addition to liver scintigraphy to detect a primary hepatic cell carcinoma, and the diagnostic accuracy of both methods was compared. Twenty-one of 27 cases (78%) with primary hepatic cell carcinoma showed a positive AFP titer of over 200 ng/ml. In 3 of these AFP-positive cases, no focal defects could be found in liver scintigraphy, although subsequently performed celiac angiography revealed hypervascular shadows. On the contrary, 22 of 27 cases (81%) represented well-defined focal defects on scintigraphy. In 4 of these cases with a positive scan, the result of AFP was found to be negative. The overall diagnostic accuracy for detecting primary hepatic cell carcinoma with a combination of both methods was 93%.

New diagnostic approach to brain lesions in nuclear medicine. Differential diagnosis of brain lesions with a computed brain scan diagnosis by the likelihood method

Using 240 true positive brain scans, a computer system for the differential diagnosis of brain lesions has been evaluated. Eighty-six parameters were extracted from brain scan findings without relationship to neurological signs and symptoms, and the likelihood method was adopted as an example of mathematical logic. The results of our experiment indicated that the overall accuracy was 77 per cent for the maximum likelihood method. The digital computer gave satisfactory results, particularly for diseases such as infarct, meningioma, acoustic neurinoma, and subdural hematoma. In spite of several problems to be solved, this method could provide invaluable help in differential diagnosis of brain lesions.