The radiation argument continues to heat up (no pun intended…) on both sides of The Pond. All of the major radiology conferences this year such as RSNA, Chicago and ESR, Vienna had comprehensive lectures and open debate sessions to address the unavoidable topic of radiation dosing. CT scanners have become so ubiquitous and overused by clinicians that the risk benefit equation is being tipped.
Clinicians to blame?
Undoubtedly, a lack of understanding of the enormity of the problem of radiation induced cancer from diagnostic imaging lies at the heart of clinicians love and overuse of CT. Clinical decisions have been realigned by the incredible diagnostic accuracy of the detailed 3D images modern multiplanar multidetector scanners achieve in a matter of seconds. Even critically ill patients previously deemed too unstable for the scanner can now be quickly processed and dispatched safely back to their intensive unit whilst images are being deciphered.
Clinicians have no formal training in radiation protection and can only see the benefits of CT. Radiologists have a duty to protect the patient from unnecessary and excessive radiation which does not contribute significantly to a change in management. But, don’t we risk pissing off our clinician colleagues and losing our purpose if we deny studies? Just one of the dilemmas radiologists must address.
Law, the leveller
It would seem that if we are not careful, the strong arm of the law will step in and help us make that decision. With cancer risks as great as 1/2000 per individual study (patients may undergo multiple per hospital stay) it is easy to see why the radiation protection lawyers have found a new sport.
Time for consent
If we are to strike a balance, the risks of a study need to be put on the table for the patients and clinicians to see.
In my mind that means, time to take informed consent at least for younger patients for whom the likelihood of further CT scans in their lifetime is high. The stochastic effects of radiation are most pronounced in those with a long life ahead of them and the paediatric population are an exquisite special risk group in their own right due to rapidly developing cells which are more radiation sensitive.
What should the consent form say?
I envisage a CT radiation consent form should:
- Explain that a test has been advised by the referring clinician and may help management.
- Highlight that there is a lifetime risk of cancer associated with every CT study
- List the cancer risks for the most common CT studies and quote the regional annual background radiation dose as a reference range
- Name the clinician and consultant radiologist supervising the study
- Ask for informed consent from the study subject