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T Wøhni

Publications and source records attributed to T Wøhni.

5 recordsLinked to original sources
PubMed2005

Measurements of finger doses in x-ray guided surgery, nuclear medicine and research.

The Norwegian Radiation Protection Authority has performed measurements of finger doses to nuclear medicine staff exposed to 99Tc(m), researchers handling 32P, surgeons performing X-ray guided orthopaedic surgery and surgeons and radiologists performing X-ray guided endovascular treatment of abdominal aortic aneurysms (AAA). Calibrations were done with X-ray qualities N-40, N-60 and N-300 and with the beta source 90Sr + 90Y. Annual doses were estimated for the nuclear medicine staff and the orthopaedic surgeons. The mean annual finger dose to nuclear medicine staff exposed to 99Tc(m) was estimated to be 18.8 mSv, and the mean annual finger dose to surgeons performing X-ray guided orthopaedic surgery was 13.7 mSv. The surgeons and radiologists performing X-ray guided endovascular treatment of AAA received a mean finger dose of 0.35 mSv per treatment. The majority of researchers handling 32P received no finger dose at all, and the maximum reading was 1.65 mSv. All occupational groups received finger doses well below the annual finger dose limit of 500 mSv.

Aortic Aneurysm, Abdominal↗
PubMed2003

Energy and directional response for the Harshaw dosemeter holders 8814 and 8891, and its effect on the appropriate radiation qualities for absolute calibration.

The personal dosimetry laboratory at the Norwegian radiation protection authority utilises a two-element dosemeter card for measuring Hp(10) and Hp(0.07), in a Harshaw dosemeter holder type 8814. Energy and directional responses for photons and betas for this holder have been assessed, as well as for the new Harshaw holder type 8891. The energy response characteristics for the 12-1250 keV photon energy range, in terms of TL output per unit Hp(10) and Hp(0.07) have been evaluated. The maximum over-response to under-response ratio for the Hp(10) element was found to be 1.46 for the new type 8891 holder, as compared to 1.55 for the older type 8814. The new holder also displays a more favourable directional response for this element. For the Hp(0.07) element, no significant differences with regard to energy or directional responses were found. Selecting radiation energy for absolute calibration of the Hp(10) and Hp(0.07) elements are discussed.

Beta Particles↗
PubMed1984

Red bone marrow doses, integral absorbed doses, and somatically effective dose equivalent from four maxillary occlusal projections.

Phantom measurements of red bone marrow (RBM) doses, integral absorbed doses, and somatically effective dose equivalent (SEDE) from four different maxillary occlusal projections are presented. For each projection, different combinations of focus-skin distances and tube potentials were compared with regard to the patient's radiation load. The axial incisal view produced the highest patient exposures, with a maximum red bone marrow dose of 122.5 microGy/exposure, integral absorbed dose of 8.6 mJ/exposure, and SEDE values of 39.6 microSv/exposure. The corresponding values from the frontal, lateral occlusal, and tuber views ranged between 4% and 44% of the axial incisal view values for the integral absorbed dose and SEDE values, and between 0.3% and 3% for the red bone marrow doses. Increasing the focus-skin distance from 17.5 cm to 27 cm is accompanied by a 24% to 30% reduction in integral absorbed dose. Increasing the tube potential from 50 kV to 65 kV likewise results in a 23% reduction in absorbed energy.

Absorption↗