MEDRADSC 2F03 Lecture Notes - Lecture 11: Radiodensity, Photon, Radiography

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

Document Summary

Ratio of height to width of interspaces. H/d: h= lead strip height, d= interspace width. The higher the grid ratio, the more narrow the deviation, the less likely photons will pass through, the more scatter it absorbs, will need more technical factor to get to the ir. High grid ratios increase the need for more patient dose. Grid frequency: number of radiopaque strips (grid strips) per centimeter (25-80 lines/cm). Grids with high grid frequency show less distinct on an x- ray compared to grids with a low grid frequency. By combining the information from grid ratio and grid frequency = determine the total quantity of lead in the grid. The higher the grid ratio, the thinner the lead strips. The closer the strips, the higher the frequency. Lead content= mass per unit area or grams per cm2. As lead content increases, grid efficiency increases (the ability to remove scatter)