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Marzanna Obrzut

Publications and source records attributed to Marzanna Obrzut.

2 recordsLinked to original sources

Phantom studies for possible dose reduction in CT head procedures.

This paper presents the results of phantom studies to investigate possible dose reduction in relation to image quality in head examinations. The studies were performed using five single-slice computed tomography (CT) scanners. Beginning from the manufacturer's protocols (i.e. default protocols in the scanner software) for routine head (adult) examinations, the values of kV(p), anode current and time were modified. Low-contrast resolution and spatial resolution were controlled using a Catphan 424 phantom. Radiation dose was checked using a polymethylmethacrylate phantom and a pencil ionisation chamber. It was found that CT dose index may be reduced up to three times with practically no loss of image quality.

Head↗

[Exposure of patients as a criterion justifying radioisotope examinations (in vivo)].

Exposure of patients, known as medical exposure, is an inevitable consequence of the diagnostic and therapeutic application of ionizing radiation. This includes among others radioisotope examination in vivo. The authors evaluate diagnostic radioisotope examinations in vivo, as an artificial source of patients' exposure, in comparison with radiological diagnostics, the most common type of medical exposure, and diagnostic methods, employing physical agents other than ionizing radiation (ultrasound, magnetic field). It is expected that the results of the evaluation will provide the justifying grounds for a sensible choice of a diagnostic method among those available. On the basis of the precise data collected in 21 laboratories, the frequency of radioisotope examinations during the years 1998-2000 was estimated at about three per 1000 inhabitants. It was found that the examination of the thyroid gland, skeleton and heart were performed most frequently. The information gathered and the literature data helped to calculate an average dose per one inhabitant of Poland. The values are as follows: average effective dose per one examination--6 mSv; average effective dose per one inhabitant--0.033 mSv. It should be stressed that apart from the examinations of the thyroid gland performed with use of 1311 (16% of the total number of examinations), the average effective dose received by patients during other examinations is equal to only 2.2 mSv. Finally, the authors present the data on patients' exposure during radioisotope examinations and diagnostic examinations employing other methods. They indicate that many radioisotope examinations provide valuable diagnostic information that could not be obtained by means of other methods. Moreover, these examinations involve relatively low levels of effective doses received by patients.

Environmental Exposure↗