Biomedical subjects

M Margaliot

Publications and source records attributed to M Margaliot.

3 recordsLinked to original sources

PubMed1998

An economic evaluation of the use of rare earth screens to reduce the radiation dose from diagnostic X-ray procedures in Israel.

In Israel the diffusion of rare earth screen technology has been limited. These screens could halve the radiation dose to the patient from diagnostic X-ray radiography, with little managerial effort and without being detrimental to the quality of the diagnostic image. We estimated the total effective dose from diagnostic film radiography capable of reduction by the use of rare earth screens, based on the number of hospital and ambulatory diagnostic X-ray procedures. This number was multiplied by the computed radiation dose per body site for a series of diagnostic procedures. The annual dose was approximately 0.53 mSv per head, approximately half of which could be averted by the introduction of rare earth screen technology. Based on a fatality risk of 3% Sv-1, it is estimated that the adoption of rare earth screen technology might reduce the annual incidence of cancer by some 93 cases, half of which would be fatal after an average latency period of 18.4 years. The cost of purchasing rare earth screens on a nationwide basis is approximately $3.0 million. This cost is outweighed by a saving of $9.6 million in X-ray tube replacement costs over the period 1997-2006. Government legislation enforcing the use of rare earth screens is essential, because of the lack of prestige associated with acquiring rare earth technology, as well as institutional reluctance to accept the external benefits of reduced morbidity and mortality and/or to extend budgetary time horizons.

Cost-Benefit Analysis↗

PubMed1997

Radon exposures in a Jerusalem public school.

In December 1995, ambient radon levels exceeding 10,000 Bq/m3 were measured in a basement shelter workroom of a multilevel East Talpiot, Jerusalem, public elementary school (six grades, 600 students). The measurements were taken after cancers (breast and multiple myeloma) were diagnosed in two workers who spent their workdays in basement rooms. The school was located on a hill that geologic maps show to be rich in phosphate deposits, which are a recognized source for radon gas and its daughter products. Levels exceeding 1000,000 Bq/m3 were measured at the mouth of a pipe in the basement shelter workroom, the major point of radon entry. The school was closed and charcoal and electret ion chamber detectors were used to carry out repeated 5-day measurements in all rooms in the multilevel building over a period of several months. Radon concentrations were generally higher in rooms in the four levels of the building that were below ground level. There were some ground-level rooms in the building in which levels reached up to 1300 Bq/m3. In rooms above ground level, however, peak levels did not exceed 300 Bq/m3. Exposure control based on sealing and positive pressure ventilation was inadequate. These findings suggested that radon diffused from highly contaminated basement and ground-floor rooms to other areas of the building and that sealing off the source may have led to reaccumulation of radon beneath the building. Later, subslab venting of below-ground radon pockets to the outside air was followed by more sustained reductions in indoor radon levels to levels below 75 Bq/m3. Even so, radon accumulated in certain rooms when the building was closed. This sentinel episode called attention to the need for a national radon policy requiring threshold exposure levels for response and control. A uniform nationwide standard for school buildings below 75 Bq/m3 level was suggested after considering prudent avoidance, the controversies over risk assessment of prolonged low-level exposures in children, and the fact that exposures in most locations in the Talpiot school could be reduced below this level. Proposal of this stringent standard stimulated the search for a strategy of risk control and management based on control at the source. This strategy was more effective and probably more cost effective than one based on suppression of exposure based on sealing and ventilation. Because many Israeli areas and much of the West Bank area of the Palestinian National Authority sit on the same phosphate deposits, regional joint projects for surveillance and control may be indicated.

Air Pollutants, Radioactive↗

PubMed1987

Amiodarone-induced thyroid gland dysfunction.

Of a population of 400 patients treated with amiodarone, 97 underwent thyroid function evaluation. Of these, 20 patients proved to be thyrotoxic and 16 hypothyroid. In thyrotoxic patients, symptoms developed 2 to 36 months after starting treatment with amiodarone, the most specific laboratory finding being a high total T3 (TT3). No antithyroid treatment proved useful. Thyroid function returned to normal 3 to 7 months after stopping amiodarone therapy. In the hypothyroid group, a high thyroid-stimulating hormone was the most specific laboratory finding. These patients were treated with substitute therapy with or without withdrawal of amiodarone. The iodine content of the thyroid gland in part of this population taking amiodarone was measured by in vivo x-ray fluorescence. Patients in whom thyrotoxicosis developed showed especially high iodine contents. During treatment with amiodarone, patients at high risk of thyrotoxicosis were recognized by increasing TT3 values and higher iodine thyroid levels. A reduction in maintenance dose should be considered in this specific population.

Amiodarone↗