Dose calculation and reporting with a linear Boltzman transport equation solver in vertebral SABR

Hardcastle, N; Hughes, J; Siva, S; Kron, T

Author(s): Hardcastle, N; Hughes, J; Siva, S; Kron, T;
Details: Publication Year 2022-03,Volume 45,Issue #1,Page 43-48
Journal Title: Physical and Engineering Sciences in Medicine
Publication Type: Research article
Abstract: Vertebral Stereotactic ablative body radiotherapy (SABR) involves substantial tumour density heterogeneities. We evaluated the impact of a linear Boltzmann transport equation (LBTE) solver dose calculation on vertebral SABR dose distributions. A sequential cohort of 20 patients with vertebral metastases treated with SABR were selected. Treatment plans were initially planned with a convolution style dose calculation algorithm. The plan was copied and recalculated with a LBTE algorithm reporting both dose to water (D(w)) or dose to medium (D(m)). Target dose as a function of CT number, and spinal cord dose was compared between algorithms. Compared with a convolution algorithm, there was minimal change in PTV D90% with LBTE. LBTE reporting D(m) resulted in reduced GTV D50% by (mean, 95% CI) 2.2% (1.9-2.6%) and reduced Spinal Cord PRV near-maximum dose by 3.0% (2.0-4.1%). LBTE reporting D(w) resulted in increased GTV D50% by 2.4% (1.8-3.0%). GTV D50% decreased or increased with increasing CT number with D(m) or D(w) respectively. LBTE, reporting either D(m) or D(w) resulted in decreased central spinal cord dose by 8.7% (7.1-10.2%) and 7.2% (5.7-8.8%) respectively. Reported vertebral SABR tumour dose when calculating with an LBTE algorithm depends on tumour density. Spinal cord near-maximum dose was lower when using LBTE algorithm reporting D(m), which may result in higher spinal cord doses being delivered than with a convolution style algorithm. Spinal cord central dose was significantly lower with LBTE, potentially reflecting LBTE transport approximations.
Keywords: Algorithms; Humans; Phantoms, Imaging; *Radiosurgery; Radiotherapy Dosage; *Radiotherapy Planning, Computer-Assisted/methods; *Spinal Neoplasms/radiotherapy/secondary; Spine/radiation effects; Dosimetry; Linear Boltzman transport equation; Sabr; Spine; Vertebra
Department(s): Physical Sciences; Radiation Oncology
PubMed ID: 34813052
Publisher's Version: https://doi.org/10.1007/s13246-021-01076-1
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2024-11-01 04:13:52

Last Modified: 2024-11-01 04:19:47