An Investigation into the Feasibility of Developing Lookup Tables for Electron Cutout Factors

- Research
- An Investigation into the Feasibility of Developing Lookup Tables for Electron Cutout Factors

- Hypothesis
- An elliptical method of estimation would provide the most accurate results and would be accurate enough for clinical use.

- Methodology
- The cutout factors for a set of cutouts with circular holes were measured and used to write an equation that models cutout factors as a function of circle diameter. A formula was derived to convert the length and width of an aperture into the “radius” of an ellipse or rectangle at a given angle. A spreadsheet program was developed to calculate the radius at each angle from 1 to 360 degrees. The program then calculates the cutout factor at each radius and averages them to yield the shape’s overall cutout factor. The program was tested using patient cutouts.

- Outcomes
- The estimated cutout factors were remarkably accurate, averaging less than 0.5% error. Irregularities in the cutouts increased error. With further testing, it should be possible to use a lookup table clinically to estimate cutout factors for well-made cutouts.