Rapid RBE-Weighted Proton Radiation Dosimetry Risk Assessment.
Proton therapy dose is affected by relative biological effectiveness differently than X-ray therapies. The current clinically accepted weighting factor is 1.1 at all positions along the depth-dose profile. However, the relative biological effectiveness correlates with the linear energy transfer, cell or tissue type, and the dose per fraction causing variation of relative biological effectiveness along the depth-dose profile. In this article, we present a simple relative biological effectiveness-weighted treatment planning risk assessment algorithm in 2-dimensions and compare the results with those derived using the standard relative biological effectiveness of 1.1. The isodose distribution profiles for beams were accomplished using matrices that represent coplanar intersecting beams. These matrices were combined and contoured using MATLAB to achieve the distribution of dose. There are some important differences in dose distribution between the dose profiles resulting from the use of relative biological effectiveness = 1.1 and the empirically derived depth-dependent values of relative biological effectiveness. Significant hot spots of up to twice the intended dose are indicated in some beam configurations. This simple and rapid risk analysis could quickly evaluate the safety of various dose delivery schema.
Department of Physics, Indiana University School of Arts and Sciences, Indianapolis, IN, USA.
Mohammad A Z
MA
Qutub
Department of Physics, Indiana University School of Arts and Sciences, Indianapolis, IN, USA.
Susan B
SB
Klein
Department of Physics, Indiana University School of Arts and Sciences, Indianapolis, IN, USA Departments of Radiation Oncology, Pediatrics, and Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA jbuchsba@IUHealth.org.
Jeffrey C
JC
Buchsbaum
D004307:Dose-Response Relationship, Radiation; D006801:Humans; D018499:Linear Energy Transfer; D061766:Proton Therapy / Q000009:adverse effects / Q000379:methods; D011522:Protons; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012062:Relative Biological Effectiveness; D018570:Risk Assessment
D011522:Protons
LET; RBE; dosimetry; linear energy transfer; proton; radiation therapy; relative biologic effect; safety; treatment planning