Prog Med Phys.  2022 Dec;33(4):72-79. 10.14316/pmp.2022.33.4.72.

Proficiency Test for the Dosimetry Audit Service Provider

• Yi CY
• Kim IJ
• Park JI
• Kim YH
• Seong YM

• KMID: 2537874
• DOI: http://doi.org/10.14316/pmp.2022.33.4.72

Abstract

Purpose
The proficiency test was conducted to assess the performance of the dosimetry audit service provider in the readout practice of the dose delivered to patients in medical institutions.
Methods
A certain amount of the absorbed dose to water for the high-energy X-ray from the medical linear accelerator (LINAC) installed in the Korea Research Institute of Standards and Science (KRISS) was delivered to the postal dose audit package given by the dosimetry audit service provider, in which the radio-photoluminescence (RPL) glass dosimeters were mounted. The dosimetry audit service provider read the RPL glass dosimeters and sent the readout dose value with its uncertainty to KRISS. The performance of the dosimetry audit service provider was evaluated based on the E_n number given in ISO/IEC 17043:2010.
Results
The evaluated E_n number was −0.954. Based on the ISO/IEC 17043, the performance of the dosimetry service provider is “satisfactory.”
Conclusions
As part of the conformity assessment, the KRISS performed the proficiency test over the postal dose audit practice run by the dosimetry audit service provider. The proficiency test is in line with confirming the traceability of the medical institutions to the primary standard of absorbed dose to the water of the KRISS and ensuring the confidence of the dosimetry audit service provider.

Keyword

Proficiency test; Dosimetry audit; Absorbed dose to water; Primary standard; Traceability

Figure

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  Fig. 1 Irradiation of the 6 MV X-ray beam on the postal audit package. (Left) before irradiation onto the postal audit package in which the glass dosimeters were not located, and (right) after irradiation onto the glass dosimeters located in the plastic phantom. (a) external monitoring chamber of the beam, (b) aluminum block for mounting the reference chamber, (c) plastic phantom of the postal audit package.

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  Fig. 2 The evaluated values of the absorbed dose to water, XKRISS and xlab with their uncertainties of UKRISS and Ulab in 95% confidence level (k=2). KRISS, Korea Research Institute of Standards and Science.

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  Fig. 3 En number of the dosimetry audit service provider. If the absolute value of En number is less than or equal to 1, the performance shall be decided to be “satisfactory” according to the decision rule of conformity given in ISO 17043 [3].

Reference

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