X-Ray Grids

1. Invented by Gustave Bucky in 1913

2. Principle fxn is to improve film contrast.

3. Usually made of lead and a filling material (plastic, aluminum, fiber)

4. Grid material is 50 microns thick

5. Interspace material is approx. 350 microns thick

6. Remove between 80-95% of scatter xray from patient.

Grid ratio:

1. Height of strip / interspace thickness

2. 6:1 – 16:1

3. Higher grid ratios = higher patient doses.

4. Grid frequency is the number of lead lines per unit measure.

Types of grids:

1. Linear or Parallel

2. Focused

3. Crossed

Grid Recommendations:

1. 12:1 ratio with 103 lead lines per inch. (Guebert likes 10:1)

2. Focused from 40 to 72 inches and aluminum interspaced

3. 18’ x 18’ for sectional films

4. 18’ x 36’ for scoliosis screens

Category: Radiology Notes