Thursday, December 29, 2011

Radiation in CT scans, x-ray/radiographies and PET scans (II): the socio-economic environment

This is the second of a series of 3 posts describing:
  1. The value and cost/harm of medical tests involving radiation, purely from a scientific perspective.
  2. Other factors affecting the prescription of these tests. This post.
  3. What to do if a doctor recommends such a test.
One would think that prescribing a medical test should depend only on the scientific trade-offs. Unfortunately there is a pile of evidence pointing to this not being the case, and that other reasons like economic as well as social play a strong influence on such prescriptions. The following is mostly center in US and few of these reasons may not apply to other regions with, for instance, different healthcare systems.

One can find a good introduction in these two articles:
  1. If you Google hard enough, you can find forums where doctors admit prescribing CTs to cover their ass. You can't blame only doctors for that, as the US society as a whole is prone to sue doctors, so, naturally doctors practice defensive medicine.
  2. Patients are also guilty of looking for fast medicine/results. Imaging certainly can help to shorten the diagnosis (like it could do cutting you wide open) but patients just don't think or don't know the effects.
  3. Doctors themselves are not the most knowledgeable out there on radiation and its effects/risks.
  4. Imaging is a good source of income for the medical establishment.
  5. The big imaging instrument manufacturers (GE, Philips, Siemens and Toshiba mainly) do want to sell as many of these machines as possible and apparently in some cases do practice borderline marketing.
  6. Patients rely on the doctor (or the system?) warning them ahead of any risks. Unfortunately, patients do not understand that the warnings are NOT for the patients but to cover the medical establishment against law suits should something wrong happen. The awful beauty of radiation based imaging tests is that its effects can usually only be seen after many years and with no conclusive way to trace them back to the original test. As such, many hospitals, doctors, etc... do no see any reason to warn patients about these risks as they very likely will not be found guilty of a future cancer, and warning the patient may create delays, discussions, or ultimately the patient opposition to such a test. If you think this is an exaggeration, you should wonder why although in some places the consent form for a CT scan may include radiation risks ( on many more (see or the Medical City Hospital in Dallas, which I happen to know from first hand) this may be limited to the contrast risks, which are on the same order or lower than the radiation risks.  The effects from the contrast are immediate while the effect from the radiation would take decades to manifest. 
Notice that, for instance, a different health system, like the public one where doctors get paid no matter what they prescribe and where the government is actually pressured to save costs (as taxes are paying for the tests) will create protocols where the test has to be strongly justified.

So, after all this information, what can a patient do to know if the test in needed or not? Please see the 3rd post for some suggestions...

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