Regular dosimetric auditing is vital in ensuring accurate radiation dose delivery in external beam radiotherapy. The department has identified a gap in regulatory controls in respect of dosimetric auditing of linear accelerators used in radiotherapy. In order to address this regulatory gap the department has developed new dosimetric auditing requirements which have been specified in the document Requirements for independent dosimetric auditing of linear accelerators.
Following a consultation period in late 2016, the document was applied as a condition of a management licence in July 2017. Management licence holders are now required to ensure that the dose delivery performance of linear accelerators is audited at a specified frequency by an independent audit service provider recognised by the department.
The auditors recognised by the department have been listed in Appendix A of the document. In order to maximise the effectiveness of the audits it is recommended that sites that have previously been audited by an auditor recognised by the department continue to be audited as per the auditor’s auditing schedule.
Recommended audit sequence
For newly constructed sites it is recommended that the audits be performed in the following sequence:
| Year | Audit description |
|---|---|
| 1 | Level Ib audit on all linear accelerators and level III on at least one linear accelerator at a site |
| 2 | Level I audit on all linear accelerators |
| 3 | Level II audit on at least one linear accelerator at a site |
| 4 | Level I audit on all linear accelerators |
| 5 | Level III audit on at least one linear accelerators at a site |
| 6 | Level I audit on all linear accelerators |
| 7 | Level II audit on at least one linear accelerator at a site |
Frequently asked questions
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The department intends to impose the new requirements as a condition (condition M1737) on all relevant management licences in early 2017-2018 financial year. The department will advise all licence holders that will be affected by this change when the condition is applied.
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When the requirements are imposed a Level Ib audit will be required to be performed on all linear accelerators upon commissioning and prior to patient treatment. This requirement will only apply to linear accelerators commissioned after the new requirements are imposed.
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When the requirements are imposed a Level I audit will be required to be performed on all linear accelerators within 2 years of the requirements being imposed and then at intervals not exceeding 2 years thereafter.
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When the requirements are imposed a Level II audit will be required to be performed on at least one linear accelerator at a site within 4 years of the requirements being imposed and then at intervals not exceeding 4 years thereafter.
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When the requirements are imposed a Level III audit will be required to be performed on at least one linear accelerator at a site within 4 years of the requirements being imposed and then at intervals not exceeding 4 years thereafter.
A Level III audit will also be required to be performed on at least one linear accelerator at a new site upon commissioning and prior to patient treatment. This requirement will only apply to new sites commissioned after the new requirements are imposed.
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The department will assess submissions from service providers seeking recognition as an approved auditor on a case by case basis. A service provider seeking to become a recognised auditor for the purpose of management licence condition M1737 can make a submission in writing to radiation.safety@dhhs.vic.gov.au
The submission must include at a minimum:
- description of auditing capability with respect to Level I, Ib, II and III audits described in the document Requirements for independent dosimetric auditing of linear accelerators, and
- evidence of NATA accreditation to ISO 17025 standard or equivalent, and
- copies of quality manual and standard operating procedures in respect of Level I, Ib, II and III audits described in the document Requirements for independent dosimetric auditing of linear accelerators.
Reviewed 16 January 2019