Enhanced bremsstrahlung spectrum reconstruction from depth-dose gradients.
We present a technique to significantly improve the accuracy of bremsstrahlung spectra reconstructed from central-axis depth-dose data using inverse methods. While typical approaches directly use the measured depth-dose data, we show the advantage of using the gradient of these data for reconstruction. The inverse problem in terms of gradients is shown to be markedly less ill-conditioned than the usual inverse problem. In each case, a regularization is introduced to alleviate the effects of noise due to measurement and computation. The error in taking derivatives of depth-dose data is demonstrated to be sufficiently controllable as not to overtake the improvements in the conditioning of the inverse problem in a pair of simulated examples.
Paniak
L D
LD
4pi Solutions Inc., Kitchener, ON, Canada. ldpaniak@fourpisolutions.com
Charland
P M
PM
D000465:Algorithms; D003198:Computer Simulation; D008962:Models, Theoretical; D009010:Monte Carlo Method; D010315:Particle Accelerators; D017785:Photons; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage