Confidentiality Statement

VSL keeps all data regarding the performance of individual participants, or groups of participants, strictly confidential. Data is accordingly protected and stored in areas on networks with restricted access. The relationship between results and the laboratories that submitted them will never be disclosed. Only the laboratory is granted access to its performance through the assigned code number.

Criteria of Participation

Participation is open to any laboratory or radiotherapy hospital which is capable of performing reference dosimetry in terms of absorbed dose to water, Dw, in high-energy photon beams (Co-60 or 6 MV – 18 MV x-rays) according to internationally accepted Codes of Practice (e.g. NCS-18, TRS-398, TG-51, etc.).

Quantities to be Measured

Absorbed dose to water, Dw, in the unit gray (Gy), at 10 cm depth in clinical photon beams between 6 MV and 18 MV of the participating laboratory or radiotherapy hospital.

Schedule

This programme is organised as an ongoing proficiency test and will operate on a calendar year basis.

The proficiency test will start as soon as the participant has registered on the site. After registration. the specific date for the dosimetry audit will be determined in agreement with the participant. The equipment required for the PT will be delivered by courier to each participant. Each participant will have one week to perform irradiation of the phantom and detector and submit their results. The aim is to release the PT report no later than three weeks after return of the equipment to VSL. Detailed instructions and contact information will be provided.

Travelling Standard

The traveling standard and equipment is a small full-scatter PMMA-phantom with radiochromic films. The phantom and films should be handled according to the instruction and with care.

Method and Equipment

Participants are advised to use their own methods and equipment for beam calibration before performing the irradiation of the phantom and films. These should be carried out in accordance with international Codes of Practice and within the scope of the laboratories or radiotherapy hospital usual practices.

Instructions and Protocol

VSL will provide the PT protocol before shipping the instruments. A report sheet will be provided by email to submit the results. The traveling equipment will contain a clear and concise instruction sheet. Each participant will have one week to perform the measurements and submit the results.

Assigned Value

Reference values will be determined by VSL using traceable calibrated standards. These assigned values form the basis for evaluating each participant’s measurement results.

Performance Evaluation

The results will be evaluated using the normalized error (En-score).

Interpretation of the En-score is as follows:

|En| <= 1 Satisfactory performance

|En| > 1 Unsatisfactory performance

The final report presents results anonymously. Each laboratory can identify its own performance via a unique code. VSL guarantees full confidentiality and does not share individual data with third parties.

Deliverables

Upon completion of the PT, each participant will receive:

• An individual performance evaluation (3 weeks after return of the equipment);
• A detailed report with anonymized results (at the end of a calendar year or pre-defined period).

This report may serve as supporting evidence for accreditations, clinical trials and (internal) quality reviews.

Criteria of Participation

Participation is open to any laboratory or radiotherapy hospital which is capable of performing reference dosimetry in terms of absorbed dose to water, Dw, in high-energy photon beams (Co-60 or 6 MV – 18 MV x-rays) according to internationally accepted Codes of Practice (e.g. NCS-18, TRS-398, TG-51, etc.).

Aims and Scope

Proficiency Tests (PT) give participants the opportunity to demonstrate technical competence, meet accreditation requirements, and/ or gain confidence by comparing their results with those of other laboratories or radiotherapy hospitals. They also provide independent insight into measurement performance, strengthen quality systems, and support risk management in line with ISO/IEC 17025:2017.

Each PT consists of a postal beam output audit focused on reference dosimetry in 4 clinical photon beams of the participant’s choice (6 MV – 18 MV, FFF and/ or is MRL possible), conducted in accordance with NCS-18, TRS-398, or equivalent internationally recognised protocols.

Quantities to be measured

Absorbed dose to water, Dw, in the unit gray (Gy), at 10 cm depth in clinical photon beams between 6 MV and 18 MV of the participating laboratory or radiotherapy hospital.

Travelling Standard

The traveling standard and equipment is a small full-scatter PMMA-phantom with radiochromic films. The phantom and films should be handled according to the instruction and with care.

Equipment Choice

Participants are advised to use their own methods and equipment for beam calibration before performing the irradiation of the phantom and films. These should be carried out in accordance with international Codes of Practice and within the scope of the laboratories or radiotherapy hospital usual practices.

Terms of payment

VSL will provide the PT protocol before shipping the instruments. A report sheet will be provided by email to submit the results. The traveling equipment will contain a clear and concise instruction sheet. Each participant will have one week to perform the measurements and submit the results.

Assigned Value

Reference values will be determined by VSL using traceable calibrated standards. These assigned values form the basis for evaluating each participant’s measurement results.

Deliverables

Upon completion of the PT, each participant will receive:

• An individual performance evaluation (3 weeks after return of the equipment);
• A detailed report with anonymized results (at the end of a calendar year or pre-defined period).

This report may serve as supporting evidence for accreditations, clinical trials and (internal) quality reviews.