Search PubMedSearch

SEARCH · Search PubMed

Results for “Radioisotopes”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

[Remote system for the mass production of short-lived radioisotopes in a cyclotron. Development of the system and radioisotope production].

A system was developed for producing short-lived radioactive substances (11CO, 11CO2, 13NN, 13NH3, 18F-, 62Zn2+, 123I-, etc.) on a scale enough for clinical use, which could also be used for analyzing them rapidly and for investigating their production methods, with less received dose by workers. The system enabled us to produce remotely several tens mCi of of short-lived radioactive susbtances readily usable for clinical diagnosis, continuosly for radioactive gases, 11CO, 11CO2 and 13NN, or repeatedly at short intervals for radioactive aqueous solutions of 13NH3, 18F-, etc. Employing this system, the average received dose per month was reduced considerably.

Carbon Radioisotopes

[Correlation between gastrointestinal absorption and uptake of radioisotopes by the critical organs].

This study was undertaken to investigate the correlation between gastrointestinal absorption of radioisotopes and uptake by the critical organ during the same period using 85Sr, 109Cd, 131I and 203Hg as radioisotopes. When the distribution of 85Sr, 109Cd, 131I and 203Hg in mice were investigated by means of the whole body autoradiography, these critical organs were determined as follows; 85Sr: bone, 109Cd: liver, 131I: thyroid gland and 230Hg: kidney. When the correlation between the injected dose and the uptake dose by the critical organ of 85Sr, 109Cd, 131I and 203Hg were investigated, uptake dose the critical organ expressed as cpm per gram of organ was in direct proportion to the injected dose and that expressed as % of the injected dose per gram of organ was held constand in either case. When the coefficient of correlation between gastrointestinal absorption and uptake by the critical organ of 85Sr, 109Cd, 131I and 203Hg were calculated, a positive correlation was revealed in either case. It is concluded from the results obtained that in vivo or in situ method, gastrointestinal absorption of radioisotopes received a support from uptake by the critical organ during the same period.

Animals

Artifactual radioassay results due to serum contamination by intravenous radioisotope administration. Falsely low serum vitamin B12 and folic acid results.

Radioisotopic contamination by recent radioisotope administration (either 99mtechnetium or 67gallium) to the patient for scanning purposes was found in 28 sera submitted for vitamin B12 or folic acid assay, or both, during the year prior to this study. In half the cases serum radioactivity was so great as to be readily identifiable during the assay. In the rest, however, the radioactivity would not have been detected had serum supernatant blanks not been routinely incorporated in the assay procedure. Many radioassay kits make no provision for such supernatant control blanks. Were it not for these blanks, five patients would have been falsely identified as vitamin B12-deficient and three others as possible deficient in the present series. Two of the five radioactive sera assayed for folate would also have given misleading results in the borderline-low range. The clinician should avoid ordering tests requiring radioassay when the patient has been given radioisotopes, and those performing radioassays must institute appropriate maneuvers to detect any such contamination.

False Positive Reactions

The particular usefulness of radioisotope methods in some benign bone diseases.

The authors have performed radioisotope examinations in 271 patients with various non-neoplastic bone diseases. According to their opinion, early diagnosis and follow-up of therapeutic results are the main characteristics which allow radioisotopes to play an important and irreplaceable role. They particularly emphasize the usefulness of radioisotope methods in femoral aseptic necrosis and Paget's disease.

Adolescent

A preliminary study of the dynamics of resolution of experimental haematomas: radioisotope studies in animals.

A preliminary investigation was carried out in order to establish a method for the study of experimental haematomas. For this purpose haematomas were produced in rabbits by subcutaneous injection of rabbits' own blood after labelling the various blood components with appropriate radioisotopes. In addition, radioisotope labelled human serum albumin and fibrinogen were studied. The results show that there is considerable variation in the rate and pattern of dissipation of the various components of the experimentally produced haematoma. The significance of these findings is discussed.

Animals

Cobalamin analogues are present in human plasma and can mask cobalamin deficiency because current radioisotope dilution assays are not specific for true cobalamin.

Since R protein binds cobalamin (vitamin B12) and cobalamin analogues, whereas intrinsic factor is highly specific for true cobalamin, we compared the serum cobalamin values obtained with these proteins in radioisotope dilution assays. With R protein, eight of 21 patients with cobalamin deficiency had serum cobalamin levels (mean, 204, range, 85 to 355 pg per milliliter) that overlapped with values for 74 normal subjects (mean, 576, range, 220 to 1230). With intrinsic factor, no patient values (mean, 36, range, less than 10 to 78 pg per milliliter) overlapped with the normal values (mean, 322, range, 130 to 785). Paper chromatography showed that these differences were due to the presence of cobalamin analogues. R protein constituted 51 to 85 per cent of the cobalamin-binding protein in 10 commercial serum cobalamin assay kits, which were said to contain "intrinsic factor". Human plasma contains cobalamin analogues that can mask cobalamin deficiency with current radioisotope dilution assays.

Adult

[Imaging of the bronchial blood flow usingg RI-angiography--study on its procedure and application of dual radioisotope technique (author's transl)].

RI-angiography with 99mTcO4- was carried out using a scintillation camera with a digital minicomputer for the purpose of imaging of bronchial blood flow in various lung diseases, and as application of dual radioisotope techniques, other imagings such as tumor imaging with 197HgCl2 or 67Ga-citrate and/or perfusion imaging with 99mTc-MAA, were performed simultaneously in patients remaining the same position, too. The image as a iso-count map extracted out of the image of 197HgCl2, 67Ga-citrate or 99mTc-MAA, was superimposed to the brightness image of RI-anigogram (aortic phase). By these procedures, the image of bronchial blood flow were obtained in some patients with lung cancer, pulmonary tuberculosis, lung abscess, and chronic bronchitis. The dual radioisotope techniques using RI-angiography and the other imaging were useful to make isotope diagnosis of lung diseases more reliable, and the image superimposition methods using RI-angiogram and the image of tumor or perfusion, were useful to improve anatomic orientation of the former.

Bronchial Arteries

Measurement of cell-mediated inflammation in experimental murine autoimmune encephalomyelitis by radioisotopic labeling.

A radioisotopic index test was used to detect that time of onset and intensity of cell-mediated immune inflammation of experimental autoimmune encephalomyelitis (EAE) in mice. Mice were tested at various time intervals after an encephalitogenic immunization with mouse spinal cord to homogenate for delayed-type hypersensitivity (DTH) to myelin basic protein (MBP) by intradermal challenge with antigen in the ear pinna. After 25 hr, the intensity of DTH was measured by 125I-radiometry which depends upon the migration of 125I-UdR radiolabeled mononuclear cells into the antigen depot. Cells reactive to MBP were detected by the ear assay as early as 7 days after the initial encephalitogenic sensitization. The degree of cell-mediated immune inflammation in the brain and spinal cord during the evolution of EAE was also measured by a radioisotopic technique; increased 125I-UdR uptake could be detected in the brain 3 to 4 days before the onset of signs of EAE at days 11 to 12, whereas 125I-UdR in the spinal cord was detected only 1 day before, or concomitant with, the onset of signs of EAE. Both, or concomitant with, the onset of signs of EAE. Both the "ear" and "organ" radiometric index tests are useful in measuring the degree of cell-mediated inflammation in EAE, and supplement routine histopathological and observational assessments.

Animals

Radioisotope therapy in bone and joint disease.

The short range tissue destruction of beta-emitting radioisotopes can be utilized in painful metastatic disease of the skeleton by employing a radionuclide that is specifically metabolized in or adjacent to these lesions. Sodium phosphate P 32 has been used for this purpose for the past 25 yr. It uptake in skeletal tumor and in osteoblastic new bone adjacent to tumor can be markedly increased by pharmacologic stimulation using androgenic steroids, or during rebound deposition after a course of parathyroid hormone. Although efficacy in terms of subjective pain relief is high, more objective signs of success are often lacking, and survival, while more confortable, is not prolonged. Marrow depression is the most significant side effect. A beta-emitting, bone-seeking isotope, 89Sr, may have a better therapeutic/toxic ratio, and should receive further trial. Radiation-induced necrosis has also been applied, though more hesitantly, to the proliferative, destructive, but nonmalignant synovium in rheumatoid disease. Here, a number of colloidal preparations, most commonly 198Au, have been employed. Again, relief of symptoms, particularly recurrent joint effusions, is quite high, although the basic disease process is not reversed. The major hazard here appears to be leakage of material to regional lymph nodes, resulting in irradiation of circulating lymphocytes. Although chromosomal damage can be detected when such cells are then cultured, the actual consequences of this, if any, are not presently known. Both shorter-lived (165Dy) and longer-lived (32P) larger-size colloids are being evaluated, which may prove safer in this regard than 198Au.

Bone Marrow

Microdosimetric measurements of ionization by some radioisotopes.

Microdosimetry has been a fast growing field in dosimetry during the last years. We have measured and calculated microdosimetric quantities which are important in correlation between the energy deposited in microscopic volumes and the biological effect. We have measured the energy distribution spectra in volumes with diameters of 1 and 2 mum and calculated the dose mean of specific energy and the mean event number per unit absorbed dose for the radioisotopes: 60Co, 137Cs, 99Tcm, 125J and the beta emitter 90Sr.

Cesium Radioisotopes

Discussion paper: specific paralysis of the antitumor cellular immune response produced by growing tumors studied with a radioisotope footpad assay.

The kinetics of the antitumor cellular immune response of mice with progressively growing syngeneic tumors were determined in vivo using a quantitative radioisotopic footpad assay. A close correlation was found between the size of the tumor and the degree of the cellular immune response. An initial phase of cellular immune stimulation was followed by specific suppression and subsequent immunologic paralysis as the tumor grew larger. This immune paralysis was attributed to increased tumor load since a homogenate of an SV40 transformed fibrosarcoma injected intraperitoneally into tumor-immune mice specifically depressed their cellular immune response. The fraction of the tumor homogenate that brought about this depression was present in the high speed supernatant and pellet of a 3M KCl extract of the tumor. The specificity of the depression was determined in vivo by the radioisotopic footpad assay and in vitro by a 51Cr cytolysis assay. Unwashed spleen cells harvested from mice bearing large tumors were unreactive in a local adoptive footpad assay. However, reactivity could be restored by repeatedly washing the spleen cells.

Animals

Hydrocephalus after subarachnoid bleeding. A correlation of clinical findings, the results of radioisotope Cisternography and computer-assisted tomography.

Out of a group of patients suffering from a spontaneous subarachnoid hemorrhage 27 patients were checked by computer-assisted tomography (CAT), 23 patients by radioisotope cisternography, and 21 patients by both diagnostic procedures. The results were correlated with the clinical observations. The flow of the CSF was normal in 7 patients (30.43%), and pathological in 16 patients (69.56%). Of the 27 patients checked by CAT, 23 (85.18%) showed a ventricular dilatation, which in 17 patients (62.96%) was not connected with a corresponding increase of the cisterns of the convexity. The clinical symptoms of hydrocephalus, the degree of impairment of the circulation of the CSF determined by radioisotope cisternography and the ventricular diameter as determined by CAT correlated well.

Adolescent

Evaluation of left ventricular function (ejection fraction and segmental wall motion) by single pass radioisotope angiography.

Changes in ejection fraction (EF) and segmental wall motion (SWM) have been shown to be sensitive indicators of left ventricular (LV) function. This information is only obtainable by contrast angiography or gated blood pool scans. Gated studies assume a fixed geometry for the LV for EF determinations, are lengthy and limited primarily to the LAO projection. We correlated contrast and Tc-99m pertechnetate angiograms by singl pass radioisotope angiography (immediately preceding the contrast study) in 12 patients. EF was calculated from the LV time/activity curve and values ranged from .21 to .72. Angiographic correlation yielded r = 0.97. Regional LV wall motion was evaluated by dividing a summated cardiac cycle into 16 frames and dynamically and sequentially displaying these frames. Regional wall motion evaluation of four LV quadrants correlated well with angiography (r = 0.97). For quantitation these images were divided into four anterior and four inferior segments and the areas of respective segments were compared and expressed as a shortening fraction. SWM compared favorably with angiographic determinations (r ranged from 0.70 to 0.99). Thus, single pass radioisotopic determinations of EF and SWM in the RAO projection correlated well with the angiographic values and provide essential quantitative information of LV function otherwise unobtainable at the bedside.

Adult

Quantitative analysis of radioisotopic angiography in trophoblastic neoplasia.

The diagnostic significance of radioisotopic angiography in the clinical management of trophoblastic neoplasia was studied by analyzing the patterns of radioisotope (RI)-dynamic curve obtained by processing sequential image with a computer, and an attempt was made to express numerically the size of tumors present in vivo. It was demonstrated that the total activities of RI in the abnormal phase of RI-dynamic curves in trophoblastic neoplasia were closely correlated with the sizes of the intrauterine tumors actually resected.

Angiography

[Computer processing of radioisotope images. Hybrid processing system].

A hydrid type image file and processing system are devised by the author to file and the radioisotope image processing with analog display. This system has some functions as follows: 1) Ten thousand images can be stored in 60 feets length video-tape-recorder (VTR) tape. 2) Maximum of an image on the VTR tape is within 15 sec. 3) An image display enabled by the analog memory, which has brightness more than 15 gray levels. 4) By using the analog memories, effective image processing can be done by the small computer. 5) Many signal sources can be inputted into the hybrid system. This system can be applied many fields to both routine works and multi-purpose radioisotope image processing.

Computers, Hybrid

The radioisotope spleen scan in the assessment of patients with suspected spleen trauma.

The radioisotope spleen scan was reviewed in 29 patients with suspected trauma of the spleen who had been admitted for observation to a surgical ward. At the time of the study, all patients had stable pulse rates and blood pressures. The scans of six patients showed space defects and, of these, splenic injury was subsequently proven operatively in five patients. As a detector of splenic trauma, the radionuclide scan proved to be reliable. Although the findings of radioisotope scanning are not specific for trauma, the interpretation of the scan in conjunction with other observations increases the accuracy of diagnosis.

Adolescent