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PubMed · 9262026

Comparative evaluation of Wellhöfer ion chamber array and Scanditronix diode array for dynamic wedge dosimetry.

T Ackerly·S Todd·I Williams·M Geso·J Cramb
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Abstract

Normalised profiles have been measured using the Scanditronix diode array and the Wellhöfer ion chamber array for the Varian dynamic wedge. Agreement was of the order of 0.1% of central axis peak dose for an open beam at depth, 0.3% for a dynamic wedge field at depth, and up to 0.6% at the peak depth. The use of the arrays for data acquisition is discussed, including user interface limitations. Data reproducibility is determined to be of the order of 0.1% for both systems. The issue of beam hardening within dynamic wedges is discussed and resolved in terms of the dose-gradient effect. A method for interpolation between dynamic wedge profiles using open beam data is presented that allows construction of isodoses to an estimated accuracy of 0.7%. Finally a benchmark for comparison of different measuring systems based on quality assurance requirements for the enhanced dynamic wedge is suggested.

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T Ackerly, S Todd, I Williams, M Geso, J Cramb. 1997. Comparative evaluation of Wellhöfer ion chamber array and Scanditronix diode array for dynamic wedge dosimetry.. https://pubmed.ncbi.nlm.nih.gov/9262026/

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