How much is too much radiation?



June 18, 2018 - 11:00 PM

Dear Dr. Roach: A year ago, I had surgery for bladder cancer, and had a small stroke and pulmonary clot. During this past year, I’ve had five CT scans, three chest X-rays and a couple of other scans to diagnose the stroke and clot. I also had some kind of scan in radiology to put in and then take out an IV blood filter. I am having another CT scan to check kidney function and another chest X-ray in May. Now my GP says I’m due for a mammogram. How much is too much radiation? I know it’s cumulative. — R.W.

Answer: People get nervous about radiation. Fear of radiation can be rational or irrational. The irrational part is nonetheless very human: There is something fundamentally terrifying about a force you can’t see or sense in any way but that can cause terrible damage. Especially for those of us who grew up worried about atomic bombs and atomic testing, radiation is disturbing on a deep level.

There also are rational reasons to be concerned about excess medical radiation. Six CT scans in a year is a lot (the blood filter was most likely placed with ultrasound, which uses sound waves, not X-rays). It is reasonable to question the necessity for any additional X-rays.