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Investigation of central electrode artefacts of ionisation chamber effect on dose calculation using advanced calculation algorithms AAA and Acuros XB

Published online by Cambridge University Press:  18 June 2020

V. S. Shaiju*
Affiliation:
Radiation Physics Division, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
Rajesh Kumar
Affiliation:
Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
K. V. Rajasekhar
Affiliation:
Meenakshi Medical College Hospital and Research Institute, Chennai, Tamilnadu, India
George Zacharia
Affiliation:
Radiation Physics Division, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
Debjani Phani
Affiliation:
Radiation Physics Division, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
Saju Bhasi
Affiliation:
Radiation Physics Division, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
Raghuram K Nair
Affiliation:
Radiation Physics Division, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
*
Author for correspondence: V. S. Shaiju, Radiation Physics Division, Regional Cancer Centre, Thiruvananthapuram, Kerala, India. Email: shaijuvs@gmail.com

Abstract

Aim:

To investigate the central electrode artefact effect of different ion chambers in the verification phantom using the dose calculation algorithms Analytical Anisotropic Algorithm (AAA) and Acuros XB.

Materials and methods:

The dosimetric study was conducted using an in-house fabricated polymethyl methacrylate head phantom. The treatment planning system (TPS)-calculated doses in the phantom with detectors were compared against the dummy detector fillets using AAA and Acuros XB algorithm. The planned and measured doses were compared for the study.

Results:

The mean percentage variation in volumetric-modulated arc therapy plans using Acuros XB and the measurement in the head phantom are statistically significant (p-value = 0.001) for FC65 and CC13 chambers. In small volume chambers (A14SL and CC01), the measured and TPS-calculated dose shows a good agreement.

Findings:

The study confirmed the CT set of the phantom with detectors (FC65 and CC13) give more artefacts/heterogeneity caused a significant variation in dose calculation using Acuros XB. Therefore, the study suggests a method of using phantom CT set with the dummy detector for mean dose calculation for the Acuros XB algorithm.

Type
Original Article
Copyright
© The Author(s), 2020. Published by Cambridge University Press

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