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Biomedical subjects

E L Saenger

Publications and source records attributed to E L Saenger.

At least 19 recordsLinked to original sources
PubMed1992

Thyroid nodules in the population living around Chernobyl.

OBJECTIVE: To determine the baseline incidence, prevalence, and characteristics of thyroid nodules in the population living around the Chernobyl nuclear power plant and to compare the findings with unexposed populations. DESIGN: Prevalence study. Population samples from seven highly contaminated villages were compared with six nearby control villages of the same size and type. The data were obtained as part of the International Chernobyl Project conducted in 1990. SETTING: The study was conducted 4.5 years after the Chernobyl reactor accident that released large quantities of radionuclides, including radioiodine. PATIENTS OR OTHER PARTICIPANTS: Population samples of approximately 100 persons residing in both highly contaminated villages and control villages since the accident were compared. Individuals were selected on the basis of birth date as being 5, 10, 40, or 60 years old at the time of the study. All persons selected underwent a thyroid examination. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Two main outcome measures were used, both for thyroid nodularity: clinical palpation and high-resolution ultrasonography. RESULTS: There was no significant difference in thyroid nodularity between the study groups. Nodules were palpated in 0.7% of children and 2.9% of adults. Discrete nodules were found by ultrasonography in 0.5% of children and 14.9% of adults. Multinodular goiter was found in 3% of adults. Nodules were more common in females. CONCLUSIONS: Four and a half years after the Chernobyl accident, the incidence, prevalence, and characteristics of thyroid nodules were the same in population samples from both highly contaminated and control settlements and similar to results reported for unexposed populations in other countries.

Accidents↗
PubMed1990

Comparison of technetium-99m and iodine-123 imaging of thyroid nodules: correlation with pathologic findings.

Three hundred and sixteen patients with solitary or dominant thyroid nodules were imaged both with technetium-99m- (99mTc) pertechnetate and iodine-123 (123I). The images were preferred, but differences were small and in 27%-58% of the cases there was no difference in quality between the two radionuclides. Discrepancies between 99mTc and 123I images were found in 5%-8% of cases, twice as often in multinodular goiters as in single nodules. Cytologic/histologic examination was performed on all nodules but no correlation was found between the pathology and the type of discrepancy. Twelve carcinomas were found (4%) but none in nodules showing a discrepancy. There was great variation among the observers about the preference for radionuclides and about the existence or type of discrepancies. The slightly better overall quality of 123I scans is probably not of diagnostic significance and does not justify the routine use of 123I instead of 99mTc. Routine reimaging of 99mTc hot nodules with radioiodine for cancer detection does not appear to be necessary.

Adult↗
PubMed1987

Pulmonary embolism and lung scanning: cost-effectiveness and benefit:risk.

The cost-effectiveness of pulmonary imaging (lung scan) on the management of 2,023 patients was studied. Prior and postscan probabilities of pulmonary embolism (PE) were obtained from referring physicians. After the scan, anticoagulant therapy (ACT) was appropriately changed in 20% of the patients and confirmed in 67%. The incremental cost of scanning was $124 per patient when the prior probability was 0.01-9.99%, dropping to $38 when the probability was 10-25%. Hospitalization and ACT cost was reduced when the prior probability was 25.01-99.99%. The greatest benefit in lives saved was when the prior probability was 25-74.99%; 1.5% of this probability group would survive as a result of the change in management attributable to the scan, at a cost of $117 per life saved. The benefit:risk ratio, as measured by lives saved compared to estimates of lives lost due to radiation exposure, was of the order of 6,000:1.

Anticoagulants↗
PubMed1986

The reactor accident at Chernobyl: a nuclear medicine practitioner's perspective.

The radiation incident at Chernobyl, USSR, on April 26, 1986 was first detected in Sweden on April 29, when increased radioactivity was observed at a nuclear facility in that country. Subsequently, higher levels of radioactivity were observed in most of Eastern Europe and then in Western Europe. Increased radioactivity was eventually noted in the United States beginning about May 5. The three-day interval between the incident and its discovery outside the USSR caused great apprehension. This chain of events indicates the very important role for the nuclear medicine physician, the medical physicist and their colleagues. It is likely that this medical specialty area is staffed by personnel who are best qualified to interpret these findings and to determine the necessary course of action both for patients and the general public. The nuclear medicine specialist can provide valuable input in estimating the radiation dose impact resulting from such an incident. This estimate may be accomplished either by combining measured activity levels with the physiological and physical factors involved; or by actual in vivo counting and quantitation of radioactivity in individuals exposed to radionuclides. From the measured activities in air, water and food, and assumed intakes for various age groups, doses can be estimated both for inhalation and ingestion of radionuclides. In vivo measurements of radionuclides can be performed with conventional instrumentation used routinely in nuclear medicine laboratories.

Accidents↗
PubMed1986

Radiation accidents.

It is essential that emergency physicians understand ways to manage patients contaminated by radioactive materials and/or exposed to external radiation sources. Contamination accidents require careful surveys to identify the metabolic pathway of the radionuclides to guide prognosis and treatment. The level of treatment required will depend on careful surveys and meticulous decontamination. There is no specific therapy for the acute radiation syndrome. Prophylactic antibodies are desirable. For severely exposed patients treatment is similar to the supportive care given to patients undergoing organ transplantation. For high-dose extremity injury, no methods have been developed to reverse the fibrosing endarteritis that eventually leads to tissue death so frequently found with this type of injury. Although the Three Mile Island episode of March 1979 created tremendous public concern, there were no radiation injuries. The contamination outside the reactor building and the release of radioiodine were negligible. The accidental fuel element meltdown at Chernobyl, USSR, resulted in many cases of acute radiation syndrome. More than 100,000 people were exposed to high levels of radioactive fallout. The general principles outlined here are applicable to accidents of that degree of severity.

Bone Marrow Transplantation↗
PubMed1985

Accidental Cs-137 contamination.

Widespread use of radionuclides in medicine and industry poses the possibility of radiation accidents. We describe such an occurrence involving three industrial workers. The accident resulted from careless handling of a Cs-137 source. Evaluation of the Cs-137 whole body burden was carried out using stationary and scanning whole body counters. In addition, regional and whole body activity from contamination was assessed using an uncollimated gamma camera. This report emphasizes the value of the gamma camera for detection of radionuclide contamination in radiation accidents.

Accidents, Occupational↗
PubMed1985

Determination of clinical efficacy: nuclear medicine as applied to lung scanning.

This paper describes a Society of Nuclear Medicine sponsored study of 2,023 patients which compares two methods, logistic regression (LR) and entropy minimax pattern detection (EMPD), to evaluate efficacy. Lung scans, used in determining or excluding a diagnosis of pulmonary embolism (PE), were utilized to create the data set. The LR analysis, presented here, shows that lung scan findings have significant influence on the referring physician's diagnostic thinking. Models were developed for the probability of a signout diagnosis of PE, and equal patient groups tested the validity of these regression equations. Individual models developed on each patient group yielded similar results. This analysis shows that the lung scan results affect the therapeutic management of the patients in a beneficial direction. A comparison of the sensitivity, specificity, and predictive values of EMPD and LR was done. EMPD predicts a signout diagnosis on only 41% of cases before lung scan and 71% after lung scan; LR provides a prediction of the signout diagnosis on 100% of cases. An advantage of EMPD is that it does not require prior probability estimates. However, LR uses this estimate, thus incorporating intuitive knowledge not evaluated by EMPD.

Adult↗
PubMed1985

Application of an information-theoretic method for efficacy assessment.

An information-theoretic pattern recognition method was used to construct descriptive models of data related to 1,674 radioisotope lung scan referrals for the purpose of assessing lung scan influence on diagnosis and management of pulmonary embolism. It was observed that, relative to other clinical information available prior to the scan, the lung scan significantly improved the ability of the models to predict diagnostic and management outcomes, implying that the lung scan has significant influence on these clinical decisions.

Humans↗
PubMed1984

Myocardial scintigraphy with 99mTc-tris-DMPE in man.

Cardiac scintigraphy was performed in six patients with a documented previous myocardial infarction, in one patient with mitral regurgitation, and in four healthy volunteers following administration of 99mTc-tris-DMPE. An intense early blood pool phase permitted gated blood pool scintigraphy and left ventricular ejection fraction calculation. A myocardial phase 12-14 h later permitted myocardial perfusion imaging. The rest myocardial perfusion image quality with 99mTc-tris-DMPE appeared to be superior to the resting image quality obtained with 99mTc-dichloro-DMPE but was inferior to the resting image quality obtained with 201Tl.

Aged↗
PubMed1984

Low-level internal radionuclide contamination: use of gamma camera for detection.

The uncollimated gamma camera was evaluated as a screening tool for the detection of low levels of internal radionuclide contamination. The minimum detectable activity (MDA) is on the order of 1-4 nCi (37-148 Bq) for a 3-min sample and background counting time. Identification of unknown radionuclides at these low levels involves a systematic search and hence requires a more careful peaking method than organ imaging. Most gamma cameras are capable both of detecting a wide range (35 keV to 1.332 MeV) of gamma-ray energies in the presence of three to four radionuclides and also of distinguishing principal gamma-ray energies from Compton scatter. The differences in MDAs among gamma cameras are small, and vary primarily with the background activity. The actual contaminant activities lie between the calculated values based on measurements when the source is 10 cm away from the uncollimated detector head and using point sources both in air and with the tissue-equivalent scatter medium. The widely available gamma camera is capable of screening a large population, either suspected or actually contaminated, in the event of an emergency.

Environmental Exposure↗
PubMed1983

Relation between effective radiation dose and outcome of radioiodine therapy for thyroid cancer.

We used a combination of radioiodine scanning and quantitative radiation dosimetry to evaluate responses to therapeutic irradiation with 131I in 76 patients with thyroid adenocarcinoma. Fifty patients received 131I treatment for ablation of residual thyroid tissue after surgical thyroidectomy, and 26 had 131I treatment for metastatic thyroid cancer. Successful ablation was observed in patients receiving higher radiation doses to the thyroid--about 4.4 times those in patients whose lesions were not ablated--largely because of a longer effective half-life of 131I in residual thyroid tissue in the patients with ablated lesions. Patients with metastases that persisted after 131I therapy tended to have more advanced disease and received significantly lower radiation doses per millicurie of administered 131I than did persons whose lesions responded to treatment. Initial 131I treatment resulting in radiation doses of at least 30,000 rad to thyroid remnants and 8000 rad to metastases was associated with a significant increase in the rate of response to therapy.

Adenocarcinoma↗
PubMed1982

Effect of coronary blood flow on uptake and washout of Tc-99m DMPE and Tl-201.

After intravenous administration of Tc-99m DMPE the flow-dependent kinetics were studied in dogs during induced ischemia and during induced maximal reactive hyperemia. A control group was also studied. Mean time-activity curves obtained from the myocardial wall were compared within the same intervention group and also with other groups. During reactive hyperemia, there was a rapid and absolute increase in uptake followed by a rapid washout, whereas during ischemia there was a slow and decreased uptake followed by a slow washout. The magnitude of Tc-99m DMPE uptake during reactive hyperemia was slightly less than that of Tl-201, but the decreased uptake with ischemia was about equal for the two agents. Following maximal uptake in the myocardium the effective half-life of Tc-99m DMPE was one-third to one-fourth that of Tl-201. The similar kinetics of Tc-99m DMPE compared to Tl-201 suggests its usefulness in the evaluation of ischemic heart disease.

Animals↗
PubMed1982

Basal kinetic studies of Tc-99m DMPE as a myocardial imaging agent in the dog.

Newly synthesized Tc-99m dichlorobis(1,2-dimethylphosphino)ethane (DMPE) was investigated as a myocardial imaging agent with respect to its kinetics (dependent on both time and regional coronary blood flow), its percent organ uptake, and its imaging characteristics in the anesthetized dog. Most of these data are compared with those of Tl-201. Blood clearance of the two agents is essentially the same. Compared with Tl-201, Tc-99m DMPE shows faster overall kinetics, higher heart-to-lung ratio, equally good correlation with a wide range of regional blood flows, and higher liver uptake. At the time of peak myocardial uptake, the mean heart uptake of Tl-201 is 4.3%, compared with 2.9% for Tc-99m DMPE, yet only 0.9% uptake of Tc-99m DMPE is found in the lung as compared with 3.3% for Tl-201. These differences result in a heart-to-lung ratio of 2:1 for Tc-99m DMPE and 1:1 for Tl-201, based on the data obtained from the time-activity curve. The quantitative findings are supported by the superior quality of Tc-99m DMPE images of both normal and infarcted dog heart. The high hepatic uptake of Tc-99m DMPE is not a serious problem if images are obtained within 5-60 min after dose. These basic kinetic studies suggest that Tc-99m DMPE is a promising myocardial imaging agent.

Animals↗
PubMed1980

Clinically important radiation-associated thyroid disease. A controlled study.

We evaluated 1,266 persons who had received external radiotherapy for benign diseases in childhood. The evaluation used detailed questionnaires completed by trained interviewers and neoplastic disease registry data. The control population included 958 age-, sex-, race-, and disease-matched persons who had not received radiotherapy and 9,865 family members of the two study groups. An excess number of clinically important thyroid neoplasms, both benign and malignant, was noted in the irradiated group.

Adolescent↗
PubMed1980

Survey of 99mTc contamination of laboratory personnel: its degree and routes.

Internal contamination of personnel preparing 99mTc labeled radiopharmaceuticals was confirmed by detection of radioactivity in urine. Observation of work habits, whole-body scanner studies, nose swabs, and wipe tests in the hot laboratory demonstrated that: (a) contamination of the laboratory coat occurred during radiopharmaceutical preparation; (b) the degree of personnel contamination appeared to be higher among the short in stature; and (c) no gross evidence was found to indicate that internal contamination took place through an air-borne route. While the calculated internal radiation dose is minimal, even this could be avoided if particular precautionary practices are observed.

Absorption↗
PubMed1980

Reflections on cancer treatment and the federal agency regulations.

Medical licenses issued by the Nuclear Regulatory Commission contain the restriction that patients who are being treated with 131I should not be discharged from the hospital if the body burden is greater than 30 mCi (1,110 MB1). It is argued that there are no sound data supporting the theory that a patient receiving more than 30 mCi (1,110 MB1) of 131I is dangerous to others. This limitation may result in the use of lower, less effective doses of 131I, so that expensive, unnecessary hospitalization can be avoided. The need for adequate radiation safety programs that will advise patients and their families of the necessary precautions following therapy with 131I is discussed.

Body Burden↗
PubMed1980

Clinical Experiences in 14C-tripalmitin breath test for fat malabsorption.

The 14C-tripalmitin breath test has been used routinely in our institution for the diagnosis of fat malabsorption as well as for the differential diagnosis of malabsorption due to pancreatic insufficiency. The test was performed in 124 patients over a period of about three years. The sensitivity and specificity of the test for fat malabsorption were better than 85.7 and 87.0%, respectively, with the efficiency better than 86.4%. When used in conjunction with Viokase administration, the test is useful as a means of separating pancreatic malabsorption patients from patients with other forms of malabsorption.

Breath Tests↗