1.] Three minutes of fluoroscopy at 3 mA and 85 kVp are combined with four 0.25-second spot films at 85 kVp and 150 mA. From the figure below, what time must elapse before the procedure may be repeated? 72000, 64000 56000 48000 40000 340 32000 295/UNITE/SEC INPUT/ENERGY 24000 16000 COOLING 8000 0 2 MINUTES Anode thermal characteristics chart for a Machlett Dynamax "25" rotating anode x-ray tube. The anode beat-storage capacity is 72,000 HU. (Courtesy of Machlett Laboratories, Inc.) HEAT UNITS 2. Given the following radiographic parameters, X-ray energy is E = 50 keV, Image receptor efficiency is 30% (+ = 0.3). Peak SNR is 5 ( = 5). Attenuation coefficient for body tissun is 0.226 cm-(m, = 0.226 cm) Attenuation coefficient of the target material is 0.276 cm-(m2 = 0.276 cm) Mass-energy absorption coefficient for body issue is 0.005 m kg (m/r=0.005 mkg*) Ratio of scattered to primary X-rays is 2(R =2) what is the minimum number of incident photons and the minimum dose to visualize an object of volume 0.512 mm (x = 0.8 mm), with 2% contrast (C=0.02) through a body thickness of 0.15 m2 3.) For typical dental radiography, aperture size from X-ray source is 1mm, object distance is 5 cm, and image distance is 1 cm. Determine the blurring, lateral magnification, and geometrie unsharpness