MEDRADSC 2F03 Lecture Notes - Lecture 10: Radiodensity, Collimator, Absorbed Dose

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 2F03
• Professor: Lumsden

Document Summary

Areas of light, dark and shades of gray. Low image contrast: but we need kvp for penetration, more photons make it to the ir, less absorbed by pt. Most x-rays have energies that matches k-shell binding energies. Scattered x-ray beam (remnant) has lower energy than the primary x-ray beam. Thinking of dqe (detection quantum efficiency) scattered x-rays increase absorption of image-forming x-rays by the ir. Absorbed dose biological effect (rad or gy: all of your dose is cumulative too much absorbed dose: cancer, leukemia, cataracts the energy transferred from ionizing radiation per unit mass of irradiated material. Pa chest- 110 kvp, 3mas: entrance skin dose- 0. 1 mgy, gonadal dose- less than 1 mgy. Extremity- 60 kvp, 5 mas: entrance skin dose- 0. 5 mgy, gonadal dose- less than 1 mgy. Ct pelvis- 125kvp, 400mas: entrance skin dose- 20 mgy, gonadal dose- 20 mgy.