The onsite Level Ib audit offers a more accurate measurement of the linac output than the Level I audit and determines the absorbed dose to water per monitor unit for megavoltage photon and electron beams under reference conditions. The ACDS visit the requesting facility and perform onsite measurements in the facility’s own water tank. All other dosimetry equipment is brought in by the ACDS, ensuring an independent audit.


Water tank

The Level Ib audit meets requirements of ROHPG linac funding and is performed for new linac installations, or at the facility’s request.

The Level Ib audit consists of the following modalities:

  • Reference beams (photons and electrons)
  • FFF beams
  • Small field output factors
  • Kilovoltage therapy

ACDS audit Level Ib documentation


Audit coverage

The Level Ib audit is not part of the scheduled program and is performed at the request of the facility. It is typically conducted for new facilities or linacs, or as a part of the follow up process where other audits fall outside the passing levels.
Please contact to obtain a quote for a new linac Level Ib audit.

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