What is the approximate shutter timer error length for a 60 Co unit?

The approximate shutter timer error length for a cobalt-60 (60 Co) unit is typically between 0.1 minute to 0.2 minute. This range indicates the extent to which the timing mechanism can deviate from the intended exposure time without significantly affecting the treatment's efficacy.

In radiotherapy, it's crucial for the timing of radiation delivery to be precise. A shutter timer error in this range allows for a manageable margin of error given the nature of cobalt-60's decay and the consistent output of its gamma radiation. This reliability in timing helps ensure that patients receive the correct dose of radiation while minimizing potential harm to surrounding healthy tissues.

Understanding this error length is vital for dosimetrists and radiation therapists as they set up treatment plans and schedules, ensuring that they account for any discrepancies that might arise during treatment delivery. The other choices suggest longer error margins which would be less acceptable in clinical practice, as they could lead to substantial variations in treatment doses.