title: Evaluation of a radiation transport modeling method for radioactive bone cement.
abstract: Spinal metastases are a common and serious manifestation of cancer, and are often treated with vertebroplasty/kyphoplasty followed by external beam radiation therapy (EBRT). As an alternative, we have introduced radioactive bone cement, i.e. bone cement incorporated with a radionuclide. In this study, we present a Monte Carlo radiation transport modeling method to calculate dose distributions within vertebrae containing radioactive cement. Model accuracy was evaluated by comparing model-predicted depth-dose curves to those measured experimentally in eight cadaveric vertebrae using radiochromic film. The high-gradient regions of the depth-dose curves differed by radial distances of 0.3-0.9 mm, an improvement over EBRT dosimetry accuracy. The low-gradient regions differed by 0.033-0.055 Gy/h/mCi, which may be important in situations involving prior spinal cord irradiation. Using a more rigorous evaluation of model accuracy, four models predicted the measured dose distribution within the experimental uncertainty, as represented by the 95% confidence interval of the measured log-linear depth-dose curve. The remaining four models required modification to account for marrow lost from the vertebrae during specimen preparation. However, the accuracy of the modified model results indicated that, when this source of uncertainty is accounted for, this modeling method can be used to predict dose distributions in vertebrae containing radioactive cement.
authors.affiliation: Department of Radiological Sciences, B170 Med Sci I, University of California, Irvine, CA 92697, USA. tkaneko@uci.edu
authors.forename: T S
authors.initials: TS
authors.lastname: Kaneko
authors.forename: V
authors.initials: V
authors.lastname: Sehgal
authors.forename: H B
authors.initials: HB
authors.lastname: Skinner
authors.forename: M S A L
authors.initials: MS
authors.lastname: Al-Ghazi
authors.forename: N S
authors.initials: NS
authors.lastname: Ramisinghani
authors.forename: J H
authors.initials: JH
authors.lastname: Keyak
mesh_terms: D001843:Bone Cements; D001853:Bone Marrow / Q000000981:diagnostic imaging / Q000528:radiation effects; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000528:radiation effects; D005260:Female; D006801:Humans; D007267:Injections; D008954:Models, Biological; D009010:Monte Carlo Method; D057285:Precision Medicine; D011827:Radiation; D011879:Radiotherapy Dosage; D014057:Tomography, X-Ray Computed
chemical_list: D001843:Bone Cements