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Single isocenter treatment planning techniques for stereotactic radiosurgery of multiple cranial metastases

Journal Article


Abstract


  • Background and purpose: Whole brain radiation therapy use has decreased in favor of stereotactic radiosurgery (SRS) for the treatment of multiple brain metastases due to reduced neurotoxicity. Here we compare two single isocenter radiosurgery planning techniques, volumetric modulated arc therapy (VMAT) and dynamic conformal arcs (DCA) in terms of their dosimetric and delivery performance. Materials and methods: Sixteen patients with 2��� 18 brain metastases (total 103; median 4) previously treated with single fraction SRS were replanned for multiple lesion single isocenter treatments using VMAT and DCA using different treatment planning systems for each and three different plan geometries for DCA. Plans were evaluated using the Paddick conformity index, normal tissue V12Gy, the probability for symptomatic brain necrosis (S-NEC), maximum organ-at-risk (OAR) point doses, and total number of monitor units (MU). Results: Conformity was not significantly different between VMAT and DCA plans. VMAT plans showed a trend towards higher MU with a median difference between 18% and 24% (p ��� 0.09). Median V12Gy differences were 7.0 cm3���8.6 cm3 favoring DCA plans (p < 0.01). VMAT plans had median excess absolute and relative S-NEC risks compared to DCA plans of 8%���10% and 25%���31%, respectively (p < 0.01). Moreover for VMAT compared to DCA, maximum OAR doses were significantly higher for the brainstem (1.9 Gy; p < 0.01), chiasm (0.5 Gy; p ��� 0.02), and optic nerves (0.5 Gy; p ��� 0.04). Conclusions: In most cases DCA plans were found to be dosimetrically superior to VMAT plans with reduced V12Gy and associated risk for S-NEC. Maximum doses to important OARs showed significant improvement, increasing the ability for subsequent salvage treatments involving radiation.

UOW Authors


  •   Tome, Wolfgang (external author)

Publication Date


  • 2021

Citation


  • Velten, C., Kabarriti, R., Garg, M., & Tom��, W. A. (2021). Single isocenter treatment planning techniques for stereotactic radiosurgery of multiple cranial metastases. Physics and Imaging in Radiation Oncology, 17, 47-52. doi:10.1016/j.phro.2021.01.002

Scopus Eid


  • 2-s2.0-85100046683

Web Of Science Accession Number


Start Page


  • 47

End Page


  • 52

Volume


  • 17

Issue


Place Of Publication


Abstract


  • Background and purpose: Whole brain radiation therapy use has decreased in favor of stereotactic radiosurgery (SRS) for the treatment of multiple brain metastases due to reduced neurotoxicity. Here we compare two single isocenter radiosurgery planning techniques, volumetric modulated arc therapy (VMAT) and dynamic conformal arcs (DCA) in terms of their dosimetric and delivery performance. Materials and methods: Sixteen patients with 2��� 18 brain metastases (total 103; median 4) previously treated with single fraction SRS were replanned for multiple lesion single isocenter treatments using VMAT and DCA using different treatment planning systems for each and three different plan geometries for DCA. Plans were evaluated using the Paddick conformity index, normal tissue V12Gy, the probability for symptomatic brain necrosis (S-NEC), maximum organ-at-risk (OAR) point doses, and total number of monitor units (MU). Results: Conformity was not significantly different between VMAT and DCA plans. VMAT plans showed a trend towards higher MU with a median difference between 18% and 24% (p ��� 0.09). Median V12Gy differences were 7.0 cm3���8.6 cm3 favoring DCA plans (p < 0.01). VMAT plans had median excess absolute and relative S-NEC risks compared to DCA plans of 8%���10% and 25%���31%, respectively (p < 0.01). Moreover for VMAT compared to DCA, maximum OAR doses were significantly higher for the brainstem (1.9 Gy; p < 0.01), chiasm (0.5 Gy; p ��� 0.02), and optic nerves (0.5 Gy; p ��� 0.04). Conclusions: In most cases DCA plans were found to be dosimetrically superior to VMAT plans with reduced V12Gy and associated risk for S-NEC. Maximum doses to important OARs showed significant improvement, increasing the ability for subsequent salvage treatments involving radiation.

UOW Authors


  •   Tome, Wolfgang (external author)

Publication Date


  • 2021

Citation


  • Velten, C., Kabarriti, R., Garg, M., & Tom��, W. A. (2021). Single isocenter treatment planning techniques for stereotactic radiosurgery of multiple cranial metastases. Physics and Imaging in Radiation Oncology, 17, 47-52. doi:10.1016/j.phro.2021.01.002

Scopus Eid


  • 2-s2.0-85100046683

Web Of Science Accession Number


Start Page


  • 47

End Page


  • 52

Volume


  • 17

Issue


Place Of Publication