Question
How do I perform warmup, preirradiation and background measurement for myQA Daily?
Answer
Warm-up
The myQA Daily device does not need warm-up to reach its specified measurement accuracy.
Pre-irradiation
Ionization chambers need a minimal amount of pre-irradiation to reach a stable response and their maximum measurement accuracy.
When using the myQA Daily device with radiation fields of less than 100 MU and less than 1 Gy dose to the ionization chamber array, a minimum amount of pre-irradiation of 0.25 Gy (field size: 25 cm × 25 cm).
If the dose of the irradiation is higher than or equal to 100 MU and the dose to the ionization chamber array is higher than or equal to 1 Gy, no pre-irradiation is necessary.
For simplifying the procedure, it is recommended to pre-irradiate with at least 500 MU during the LINAC's warm up phase in the morning.
Background measurement
The device automatically performs background measurements every 20 seconds to compensate for ionization chamber leakage while no irradiation is taking place.