A simple and reliable index for scoring rival stereotactic radiosurgery plans.
OBJECTIVE
A simple and robust index for ranking rival stereotactic radiosurgery plans is presented.


METHODS
The radiosurgery plan score index, CGI (Conformity/Gradient Index), is an average of a conformity score and a gradient score. Computation of the CGI score is simple, requiring only three pieces of data: (1) the total volume irradiated to the prescription isodose level, (2) the volume of the target, and (3) the total volume irradiated at half of the prescription isodose level. The overall CGI Index is a simple function of these three pieces of data.


RESULTS
When multiple sets of rival stereotactic radiosurgery plans were ranked with respect to this single score index, the resulting plan rankings closely matched the plan rankings according to biologic indices (calculated nontarget brain normal tissue complication probabilities).


CONCLUSIONS
The CGI is a simple and fast plan evaluation tool that can assist the radiosurgery planner in evaluating and optimizing multiple candidate radiosurgery plans.
Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL 32224, USA. wagner.thomas@mayo.edu
Thomas H
TH
Wagner
Francis J
FJ
Bova
William A
WA
Friedman
John M
JM
Buatti
Lionel G
LG
Bouchet
Sanford L
SL
Meeks
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000601:surgery*; D002138:Calibration; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D016634:Radiosurgery / Q000379:methods / Q000592:standards*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods / Q000592:standards*; D020266:Radiotherapy, Conformal / Q000592:standards*