iaea human health series publications - SEDIM

TABLE 24. SPECIFICATIONS OF TEST EQUIPMENT FOR MEDICAL PHYSICIST’S TESTS (cont.)ItemRadiation dosimeter bThermometer and barometerLead sheets with apertures of variousdiameters (optional)Metal plate to shield the detector from X raysAluminium filterskV meter (required for acceptance testing,commissioning or investigationof problems only)MTF test toolResolution patternDensitometer cOptical density calibration stripMagnifierBathroom scale and towelGeometric distortion test toolPhosphorescent screens or radiochromic film(e.g. GAFCHROMIC XR-M)Radiographic ruler with ‘0’ at centreCalibrated detector at appropriate mammographic energies with an energy response ofwithin ±5%; accuracy ±5%, repeatability ±5%.To be used with dosimeter when automatic temperature and pressure correction is notavailable.To create narrow beam geometry for HVL measurement.For example, 1 mm steel, 5 mm aluminium or >0.1 mm lead, large enough to coverthe active area of the detector.At least 99.9% pure aluminium, providing thicknesses of 0.3–0.7 mm in increments of0.1 mm.Capable of measurement down to 25 kV with accuracy of ±1 kV and repeatability of±0.5 kV.A square attenuator (approximately 30 mm on a side), mounted on a backing thatallows positioning on the compression plate, or 40 mm PMMA phantom at an angleof 2–5° with respect to the chest wall at a height of 45 mm above the breast support.Bar or star pattern covering the range of measurement of at least 2–8 lp/mm.Capable of measuring in the range 0–4.0 OD and accurate to within ±0.02 OD.For measurements on dry hard copy film, the densitometer should not take the infraredlight component into account.Current and traceable to an accepted standard.Providing 4× to 5× magnificationThe scale should be a flat, conventional, analogue type. Household digital scalessample the data and may not respond properly as additional pressure is applied slowlyto the scale. Digital scales designed specifically to measure compression force inmammography may be used.With parallel lines at 20 mm spacing, lines angled at 45° to the edges of the tool.To delineate area of radiation exposure during collimation tests.For collimation and alignment tests.Requirements141