The effect of target volumes on the essential treatment plan parameter and prescription dose for the patients with vestibular schwannoma

Abstract

Author(s): Nadiya Y Mohammed*

Background: Gamma Knife Radiosurgery (GKRS) is confirmed lately to have a feasible tumor dominance and is much more probable to exclude the cranial neuropathies as the result of open surgery. This study is aimed to investigate the effect of the target volume on the assessment of the essential plan parameters including (Conformality index, Selectivity, Coverage, and Gradient Index (GIn), which are followed in (GKRS) treatment for patients with vestibular schwannoma. Methods: The Target Volume (TV) was identified for each treatment plan and involved 50 patients who underwent Stereotactic Radiosurgery (SRS) treatment for vestibular schwannoma. The assessment parameters were determined to calculate: Coverage (Cov), Selectivity (Slec), Gradient Index (GI), and Paddick Conformance Index (PCI). Result: In this study, the volumes were separated into two groups: group 1 had an average size of 2.20 ± 1.28, while Group 2 had an average size of 9.17 ± 3.95. The mean values of measurements in the two groups were as follows: Cov=0.94 and 0.93, Slec=0.69 and 0.78, GI=2.8 and 2.55, PCI=0.65 and 0.73, and time =19.6 seconds and 34.4 seconds. The dosage distribution was the same for both treatment and reference programs. Conclusion: This study demonstrated that the target volume can affect the essential plan parameters specifically during the evaluation of dose distribution in a treatment plan for vestibular showanoma.

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