Medical Physics

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Browsing Medical Physics by Author "Van der Merwe, E. J."

Now showing 1 - 4 of 4
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    Effektiewe energiewaardes van 90°- verstrooide fotone tydens urologiese en brongoskopiese stralingsondersoeke
    (1977-11) Van der Merwe, E. J.; Cilliers, F. B.
    During fluoroscopic bladder and bronchial examinations the radiation workers concerned are exposed to 90°-scattered photons. The effective energy expressed in mm Al was measured for these photons exited at tube potentials in the 60-100 kV range. An increase also depends on whether the measurements are made in the direction of the long axis or the short axis of the phantom. These findings are contrary to the recommendations stipulated in the code of practice SABS 07-1972.
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    Elektron- en lae energiefoton-kontaminasie van die stralingsbundel van 'n theratron 780-kobalteenheid
    (HMPG, 1980-08) Groenewald, W. A.; Van der Merwe, E. J.
    While high-energy photon radiation in radiotherapy of deeper tissues has a skin-sparing effect, contamination with electron and low-energy photon radiation can diminish and even abolish this effect. Experiments with perspex, aluminium and copper filtrates showed that a copper filter effectively diminished the skin dose owing to contaminated radiation.
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    Die frekwensie van herhaling van rontgenopnames
    (HMPG, 1980-01) Van der Merwe, E. J.
    A study of the rates of repeat radiography in two hospitals in the Cape Peninsula was undertaken. The relationship between these rates and the type of examination as well as the contributing factors was established. The total frequencies for the two hospitals varied from 10,1% to 14%. The predominant reasons for 78% of repeat radiographs were over-exposure, under-exposure and positioning.
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    'n Vergelykende ondersoek tussen twee kapasitorontlandings-x-straaleenhede
    (Health and Medical Publishing Group (HMPG), 1980-11) Frost, J. M.; Collins, P. D.; Van der Merwe, E. J.
    Two capacitor discharge X-ray units of different make were compared. The same radiological examinations were carried out with both units and the radiation exposure for every examination was measured on a Rando phantom with calibrated LiF-TLD Teflon discs. A large difference in radiation exposure for the same image quality was found between the two units. Factors such as the use of rare earth intensifying screens with capacitor discharge X-ray units, independent tube current settings and automatic charge replenishment are stressed.