Centenary of tele-electrocardiography and telephonocardiography.

In the history of electrocardiography the names of two physiologists stand out: Augustus Waller (1865-1922) and Willem Einthoven (1860-1927). Waller was the first to show that the beating heart produces a weak electric potential, which can be registered by a measuring device connected to electrodes attached to the skin. Einthoven developed a 'string' galvanometer, which was much faster and more sensitive than the system used by Waller. Einthoven's electrocardiograph was ready for use in 1903. To facilitate investigations of patients Einthoven connected his instrument to the Academic Hospital in Leyden, by a telephone line, as suggested by his engineering colleague Johannes Bosscha in Delft. The first successful tele-electrocardiogram was transmitted on Sunday 22 March 1905. The heart tones were registered by wiring a specially developed microphone placed on the subject's chest to another string galvanometer. The event was therefore a first both for tele-electrocardiography and for telephonocardiography. We are still awaiting the full-scale implementation of these achievements, 100 years later.

Recent EULEP dosimetry intercomparisons for whole body irradiation of mice. European Late Effects Project group.

PURPOSE: To foster quality assurance of dosimetry among the institutes involved in joint studies on late effects of ionizing radiation. MATERIALS AND METHODS: The participants in the dosimetry intercomparison received for each facility two mouse phantoms loaded with LiF thermoluminescent dosemeters (TLD) and a control badge. The participants were requested to irradiate the test phantoms in the actual arrangement used for whole body irradiation of mice, such that the dose in the centre of the test phantoms was 2 Gy and the dose distribution was uniform. The readout of the TLD and the dose evaluation were made at the organizing institute. RESULTS: Ten institutes operating 14 exposure facilities in four countries took part in the intercomparison. For one facility a dose deviation between 5 and 10% was found, whereas for two others the deviation exceeded 10%. The requirement for uniform dose distribution in a mouse phantom was not fulfilled by six exposure facilities. The causes for the dose discrepancies were found for two participants whereas for one participant the problems were only partly resolved. Non-uniform dose distributions are mainly related to unilateral irradiations. CONCLUSION: The seven EULEP dosimetry intercomparisons clearly show the need for quality assurance of dosimetry in radiobiology.

AMBER and conventional chest radiography: comparison of radiation dose and image quality.

The authors compared the radiation dose to the patient and the image quality in advanced multiple-beam equalization radiography (AMBER) with those in conventional chest radiography. Organ doses were estimated for an anthropomorphic phantom from measurements with thermoluminescence dosimeters. These measurements were supplemented with area-air kerma products obtained during chest examinations of 223 patients. Image quality was determined by means of a contrast-detail image evaluation test. An improvement in image quality in regions of high absorption and an increased dose to the patient were found for the AMBER technique compared with the conventional technique. However, for both techniques, the radiation exposure was relatively low compared with other reported values of patient dose during chest radiography. The estimated effective dose for an average-size patient during chest radiography with posteroanterior and lateral projections is 0.085 mSv for the conventional and 0.14 mSv for the AMBER technique.

Decreased iron absorption in patients with active rheumatoid arthritis, with and without iron deficiency.

Mucosal uptake, mucosal transfer, and retention of a physiological dose of ferrous iron were studied in women with active rheumatoid arthritis (RA): 19 with normal and 17 with depleted bone marrow iron stores. Control subjects were 26 normal women and 20 women with uncomplicated iron deficiency. Iron absorption was measured with 59Fe as a tracer and by whole body counting. Compared with controls, final iron retention was considerably decreased in both groups of patients with RA. Analysis of the two sequential steps of iron absorption showed that mucosal uptake was normal in iron replete patients with RA but was significantly lower in patients with RA with depleted iron stores compared with iron deficient controls. Mucosal transfer of iron was considerably decreased in patients with RA with normal iron stores. The impaired absorption of iron in patients with active RA may delay the correction of the haemoglobin concentration when anaemia of chronic disease is complicated by iron deficiency.

Radiation doses to the population in The Netherlands, due to external natural sources.

An estimate has been made of gamma doses to the population in the Netherlands, caused by natural radiation sources encountered in the environment. Data are given, derived from two independent types of measurement: Exposure/dose rate measurements in the living environment (private houses as well as workplaces), using a high pressure ionization chamber and thermoluminescent dosemeters (TLD) respectively and Individual monitoring, using TLD. The study included some 750 individuals, 400 houses and 275 workplaces. The participants were selected and divided into two groups on the basis of their location in areas of relatively high and low terrestrial radiation level respectively. Distinction was made between three categories of individuals with respect to their patterns of life. An estimate was made of the influence of the terrestrial component of the natural background and of some typical building materials on the indoor radiation level. An average indoor exposure rate of 9.5 muR . h-1 and a dose rate of 95 nGy . h-1 for individuals were found, both with a standard deviation of 15-20%.

Exposure of radiologists to scattered radiation during radiodiagnostic examinations.

The exposure to scattered radiation was measured on both hands, the forehead and gonads of six radiologists by means of thermoluminescent dosimeters in two fluoroscopy rooms. Exposure of the forehead was found not to exceed approximately 1% of the maximum permissible exposure (MPD) (3% pursuant to NCRP (recommendations). During examinations of the colon, the exposure of the right hand proved to be significantly higher compared to the left. There was only slight exposure to the gonads as measured behind the apron.

Exposure of the radiologist to scattered radiation during angiography.

At least 90% of the exposure of a radiologist's crystalline lens and right hand to scattered radiation during angiography, investigated by thermoluminescent dosimetry, proves to be due to radiography during and immediately after manual injection of the contrast medium. Therefore, manual injection should be replaced by remotely controled injection by means of an injector. The exposure of a radiologist's gonads (measured behind a lead apron) proves negligible. At the low exposure rates to be expected, integrating measurements should be made.