Performance Evaluation of a Transmission Reference Detector for Commissioning Beam Data in a Wedge Field

다국어 초록 (Multilingual Abstract)

The purpose of this study is to evaluate the performance of a \stealth chamber" as a novel reference detector for measuring the commissioning beam data for a wedge eld. The stealth chamber is a transmission ionization chamber intended to be used as a reference chamber for relative dosimetry. The percentage depth doses (PDDs) and the dose proles of 6-, 8-, and 10-MV photon beams of four wedge lters were measured using the stealth and the CC13 chambers as reference detectors. The PDD and the prole measurements were performed under various eld sizes ranging from 4 4 cm2 to 20 20 cm2. For the evaluate of the performance of the stealth chamber in elds with a physical wedge, all measurement data obtained using the stealth chamber as a reference detector were compared with those measured using two CC13 chambers as both eld and reference detectors. For the PDDs, the dierences in dosimetric parameters such as the depth of maximum dose (dmax) and the PDD at 10 cm (D10) and 5 cm (D5) were analyzed for both reference detectors.
In addition, the root-mean-square error (RMSE) was calculated to measure the agreement of the proles at dmax and a 10 cm depth. The percentage dierences in D10 and D5 between both detectors were less than 1% for all energies and elds with four wedges. Furthermore, the RMSEs of the proles at dmax and 10-cm depth in both chambers were within 1% for all energies and elds except for the 60 wedge angle. This study found that the use of a stealth chamber to measure the commissioning beam data for a wedge eld is feasible, although a relatively large dierence in the PDD was observed in the build-up region. However, we recommend careful verication of the PDDs and dose proles for large eld size and wedge angle before clinical use.

참고문헌 (Reference)

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