Relationship between radiosurgery conformity indices and acoustic neuroma tumor volume

Michael V. Lawrence, Peter Rossi, Doug Powell, Kenneth E. Ekstrand, Allan F. Deguzman, Michael T. Munley, Thomas L. Ellis, Stephen B. Tatter, Volker W. Stieber, Kevin P. McMullen, Edward G. Shaw, J. Daniel Bourland

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Background: We reviewed the relationship between 4 conformation indices (CIs) and acoustic neuroma volumes to determine how CIs change with tumor volume (TV). Methods: Gamma Knife® (GK) stereotactic radiosurgery (SRS) plans for 96 acoustic neuroma patients were examined and the prescription isodose volume (PIV), T V, and TV receiving the prescription isodose (TV PIV) were recorded. The 4 CIs calculated were the following ratios: PIV/TV, TVPIV/TV, TVPIV/PIV, and TVPIV 2/(TV × PIV). CIs were stratified based upon TV as < 2.0 cm3 (n = 49) or > 2.0 cm3 (n = 47). Results: For TVs < 2.0 cm3, the mean PIV/TV, TVPIV/ TV, TV PIV/PIV, and TVPIV2/(TV × PIV) ratios were 1.984, 0.982, 0.588, and 0.577 respectively. For TVs > 2.0 cm 3, the mean PIV/TV, TVPIV/TV, TVPIV/PIV, and TVPIV2/(TV × PIV) ratios were 1.272, 0.971, 0.777, and 0.754 respectively. Conclusions: The PIV/TV, TVPIV/ PIV, and TVPIV2/(TV × PIV) ratios improved as TV increased whereas the TVPIV/TV ratio decreased. The greatest variance in the CIs was present at very small TVs. We conclude that CIs can be used to compare GK SRS plans for target volumes > 2.0 cm3.

Original languageEnglish (US)
Title of host publicationRadiosurgery
Subtitle of host publication8th International Stereotactic Radiosurgery Society Meeting, San Francisco, June 2007
Pages95-99
Number of pages5
DOIs
StatePublished - Mar 19 2010

Publication series

NameRadiosurgery
Volume7
ISSN (Print)1024-2651
ISSN (Electronic)1662-3940

ASJC Scopus subject areas

  • Surgery
  • Radiology Nuclear Medicine and imaging

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    Lawrence, M. V., Rossi, P., Powell, D., Ekstrand, K. E., Deguzman, A. F., Munley, M. T., Ellis, T. L., Tatter, S. B., Stieber, V. W., McMullen, K. P., Shaw, E. G., & Bourland, J. D. (2010). Relationship between radiosurgery conformity indices and acoustic neuroma tumor volume. In Radiosurgery: 8th International Stereotactic Radiosurgery Society Meeting, San Francisco, June 2007 (pp. 95-99). (Radiosurgery; Vol. 7). https://doi.org/10.1159/000288722