Physicsweb Jobs

Admin | December 29, 2011 | Comments Off

Physicsweb Jobs

Physicsweb Jobs

The researchers' starting point was the original analytic expression for Bragg curves, devised by Thomas Bortfeld some 14 years ago. They adapted this expression by adding a third-order polynomial term. This corrected for the use of an oversimplified dose deposition model in the original expression, which otherwise produces a systematic discrepancy between the modelled and measured data proximal to the Bragg peak. A simultaneous optimization algorithm was then used to obtain "best fit" values for the polynomial coefficients, based upon a set of seven measured Bragg curves which ranged in energy from 126 to 212 MeV.

The accuracy of the newly adapted and optimized expression was assessed with the calculation of Bragg curves for three energies (121, 169 and 212 MeV), which were compared with reference measured data. The researchers found good agreement, observing a maximum discrepancy between the calculated and measured data of 2%.

The team then took their study one step further, testing the ability of their expression to provide a sufficiently accurate set of Bragg curves for TPS commissioning. If successful, the expression would provide an alternative approach to that used when the TPS was originally acceptance tested and commissioned, which required the time-consuming measurement of up to 94 Bragg curves for the MD Anderson scanning-beam delivery system.

Where Shmonsters Go to Play

Michal Finegold's personal artist portfolio. Also includes fun games. Creative ideas for dollhouse decorating, pumpkin carving, sticker frames, costumes, and other fun projects. ...