Frequency
- how often ?
- daily, weekly, monthly, annually
- after hardware or software changes (‘acceptance’)
- AAPM, IPEM
- agreement, daily (or weekly IPEM):
- image noise and CT number of water
- other tests:
- annually (IPEM) or semi-annually (AAPM)
- maybe more frequently to establish usual variation; especially ms ?
- depends on importance and application
- annual test can be as full as an acceptance test
- UK survey
- which tests are done and how useful; www.ctug.org.uk