Stereotactic radiosurgery of intracranial tumors: a comparison of intensity-modulated radiosurgery and dynamic conformational arc
Marcos Dellaretti, Júlio Leonardo Barbosa Pereira, Eduardo Tagawa, and Mariana Pedrini
Purpose: Intensity-modulated radiosurgery (IMRT) and dynamic conformational arc (DCA) are two techniques for linac-stereotactic radiosurgery using the micro-multileaf collimator. The objective of this study is to examine advantages and disadvantages of these techniques in the treatment of treatment of intracranial tumors.
Materials and Methods: SRS treatment plans were developed for 21 patients with vestibular schwannoma, glomus jugulare, pituitary adenoma and cavernous sinus meningioma. For all patients, we developed an IMRT and a DCA plan using BrainLab Iplan 4.1. Plans were evaluated using the target coverage conformity index (CI), homogeneity index (HI), Gradient Index (GI) and doses in critical structures (optic pathways and brainstem).
Results: In the overall comparison of both techniques, HI and CI was better in the IMRT group, showing a statistically significant difference. The GI was similar in two groups. Comparison of the mean dose in critical structures of the techniques revealed no statistically significant differences. The DCA plan was acceptable in 9 patients and IMRT in 15 patients. IMRT was preferred in 14 out of 15 patients due to better CI and lower dose in critical structures with adequate target coverage.
Conclusions: IMRT is the preferred stereotactic radiosurgery technique for most intracranial benign tumors close to critical structures.
Keywords: Intensity-modulated radiosurgery, dynamic conformational arc, radiosurgery and intracranial tumors.