I recently returned from an extended trip overseas during which my carry-on bagcontaining medications was scanned by several screening machines-both the conventionaltype and the new CT type.
I recently returned from an extended trip overseas during which my carry-on bagcontaining medications was scanned by several screening machines--both the conventionaltype and the new CT type. How does repeated exposure to x-rays affectthe potency of such medications as statins, aspirin, oral inhalers, montelukastsodium, oral antihypertensives and, above all, sublingual nitroglycerine tablets?---- N. K. Pandeya, DO
West Des Moines, IowaFew data are available on the sensitivity of particular therapeutic agents toradiation damage. However, the best way to approach this issue is tocompare the extent of radiation exposure during airport security scanswith more familiar types of exposure.The standard carry-on baggage x-ray scanner exposes material to approximately15% of the daily exposure to background radiation (which comesmainly from the radioactive decay of naturally occurring isotopes) (Table). Arecent study demonstrated that 10 consecutive passes through an x-ray scannerhad no noticeable effect on the viability and proliferative capacity of hematopoieticstem cells.1On the other hand, the scanners used to monitor checked baggage employCT technology and thus can result in much greater exposure than carryonbaggage scanners. For example, while photographic film can pass safelythrough a carry-on scanner, it may be fogged when exposed to the beam of aCT-type scanner. However, a single passage through a CT-type scanner resultsin less exposure than a year's worth of background radiation. Thus, one passageprobably will not cause significant damage--if any--to medications.Still, because exposures are much higher with the CT scanners, avoidthem if possible and keep all medications in carry-on luggage. This also circumventsthe risks and inconveniences associated with lost or delayed checkedbaggage.Finally, if you do have concerns about potential damage from the standardcarry-on scanners or if you encounter a situation where a CT-type scanner isused for carry-on items, remember that Federal Aviation Administration regulationsfor domestic flights allow you to have your carry-on items searched manuallyinstead of passed through a scanner.---- Michael M. White, PhD
Professor and Chair
Department of Pharmacology and Physiology
Drexel University College of Medicine
Petzer AL, Speth HG, Hoflehner E, et al. Breaking the rules? X-ray examination of hematopoietic stemcell grafts at international airports.