Natalie David An Investigation into the Feasibility of Developing Lookup Tables for Electron Cutout Factors
SchoolStrongsville High School
MentorMatthew Vossler, MS
DepartmentRadiation Oncology at Wooster Family Health Center
An Investigation into the Feasibility of Developing Lookup Tables for Electron Cutout Factors
An elliptical method of estimation would provide the most accurate results and would be accurate enough for clinical use.
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.
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.