Journal article
A volume-independent conformity index for stereotactic radiosurgery
Medical physics (Lancaster), v 49(5), pp 2931-2937
May 2022
PMID: 35315939
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
To develop a volume-independent conformity metric called the Gaussian Weighted Conformity Index (GWCI) to evaluate stereotactic radiosurgery/radiotherapy (SRS/SRT) plans for small brain tumors.
A signed bi-directional local distance (BLD) between the prescription isodose line and the target contour is determined for each point along the tumor contour (positive distance represents under-coverage). A similarity score function (SF) is derived from Gaussian function, penalizing under- and over-coverage at each point by assigning standard deviations of the Gaussian function. Each point along the dose line contour is scored with this SF. The average of the similarity scores determines the GWCI. A total of 40 targets from 18 patients who received Gamma-Knife SRS/SRT treatments were analyzed to determine appropriate penalty criteria. The resulting GWCIs for test cases already deemed clinically acceptable are presented and compared to the same cases scored with the New Conformity Index to determine the influence of tumor volumes on the two conformity indices (CIs).
A total of four penalty combinations were tested based on the signed BLDs from the 40 targets. A GWCI of 0.9 is proposed as a cutoff for plan acceptability. The GWCI exhibits no target volume dependency as designed.
A limitation of current CIs, volume dependency, becomes apparent when applied to SRS/SRT plans. The GWCI appears to be a more robust index, which penalizes over- and under-coverage of tumors and is not skewed by the tumor volume.
Metrics
Details
- Title
- A volume-independent conformity index for stereotactic radiosurgery
- Creators
- Seungjong Oh - Allegheny Health NetworkMusaddiq J Awan - Medical College of WisconsinJames I Monroe - John Cochran VA Medical CenterYun Liang - Allegheny Health NetworkRodney E Wegner - Allegheny Health NetworkStephen Karlovits - Allegheny Health NetworkMitchell Machtay - Penn State Milton S. Hershey Medical CenterSimon S Lo - University of WashingtonAndrew Sloan - University Hospitals of ClevelandJason W Sohn - Allegheny Health Network
- Publication Details
- Medical physics (Lancaster), v 49(5), pp 2931-2937
- Publisher
- Wiley
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Radiation Oncology (and Nuclear Medicine)
- Web of Science ID
- WOS:000782181800001
- Scopus ID
- 2-s2.0-85127962724
- Other Identifier
- 991021897329604721
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InCites Highlights
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Radiology, Nuclear Medicine & Medical Imaging