Functional relationship between the volume of a near-target peripheral isodose line and its isodose value for gamma knife® radiosurgery

Lijun Ma, Arjun Sahgal, Cynthia Chuang, Martina Descovich, Paula Petti, Vernon Smith, Lynn Verhey, Nicholas Barbaro, Michael McDermott, Kim Huang, Jean Nakamura, Penny Sneed, David Larson

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Scopus citations

Abstract

Aims: To study how the volume of a peripheral isodose line would relate to its isodose value for Gamma Knife® (GK) radiosurgery. Method: A theoretical model was developed to derive the relationship between the volume of a near-target peripheral isodose line and its isodose value. The formula was tested based on cases with uniformly matched target volumes as well as random target volumes ranging from 0.1 to 37 cc. Results: To the second order approximation, the volume of a near-target peripheral isodose line (V) relates to its dose value (D) by the following formula: V/V0 = (D/D 0)-3/2, where D0 is the prescription dose and V0 is the prescription isodose volume. Applied to patient data, we found V/V0 = (D/D0)γ, where γ = - 1.50 ± 0.16 at the 95% of the confidence level, and showed excellent agreement with the theoretical prediction. Conclusion: For GK radiosurgery, the near-target peripheral isodose volume relates to its isodose value in a similar fashion as to the way in which the volume of a sphere relates to the inverse of its surface area. Such a predictable relationship justifies the use of a single near-target peripheral isodose volume, as a sufficient measure of the dose to the normal brain.

Original languageEnglish (US)
Title of host publicationRadiosurgery
Subtitle of host publication8th International Stereotactic Radiosurgery Society Meeting, San Francisco, June 2007
Pages75-83
Number of pages9
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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    Ma, L., Sahgal, A., Chuang, C., Descovich, M., Petti, P., Smith, V., Verhey, L., Barbaro, N., McDermott, M., Huang, K., Nakamura, J., Sneed, P., & Larson, D. (2010). Functional relationship between the volume of a near-target peripheral isodose line and its isodose value for gamma knife® radiosurgery. In Radiosurgery: 8th International Stereotactic Radiosurgery Society Meeting, San Francisco, June 2007 (pp. 75-83). (Radiosurgery; Vol. 7). https://doi.org/10.1159/000288720