RADIATION EXPOSURE FROM PAEDS TRAUMA SCANS

spidermanA study from Injury quantifies the exposure to radiation from paediatric trauma scans. The study tells us children are exposed to significant doses of ionising radiation when they become trauma patients.

Background
CT has become a fundamental part of trauma assessment. Most of our hospital´s adult trauma calls result in the patients being trauma scanned. It makes sense. A study by Chen et al from 2011 how the ED primary and secondary surveys of major trauma patients misses a lot of clinically significant injuries. According to that study, 8% of clinically significant injuries were missed when comparing with the final ICU diagnose. Other studies advocate pan-scanning of polytrauma patients as it is associated with survival.

The study in Injury observes that adult trauma management, including liberal use of CT-scans and increased exposure to ionising radiation, has carried over to paediatric trauma management. The radiation part is scary. Kids are much more sensitive to ionising radiation than adults.

The study
The study in Injury was a retrospective database study aiming to quantify the total exposure to radiation from CT scans in severely injured children.  It was performed at a level trauma centre. The authors included all patients younger than 18 with an ISS score of 12 or greater. The study also looks closer at why the kids were scanned and what clinical consequence the scan resulted in.  The study only considers radiation from CT as it generates more than 90% of radiation exposure in trauma.

Results
The study identified 157 paediatric trauma patients with a mean ISS of 22.5. The average number of scans were 2.6, ranging from 0 to 16 exams. 22 patients were not scanned at all. The most common scan was head (78%) followed by chest+abdomen (55%) and spine (44%).

Screen Shot 2014-01-18 at 21.29.04The total effective dose of ionising radiation each patient was exposed to is represented by the thin columns in the diagram to the right. The maximum recommended annual dose is 3,0 mSV and is represented by the solid black line. 3,0 mSV is also what a typical person living in the west is exposed to during a year

The average radiation dose in the patients that were scanned was 13,5 mSv with CT body (chest+abdomen+pelvis) as the most significant source.

56% of scans resulted in no further action, 32% resulted in additional imaging while only 10% of scans resulted in surgery or a procedure. 2% resulted in withdrawal of treatment.

Take home message
Paediatric trauma victims are exposed to significant exposure to ionising radiation. The average patients is exposed to more than four times the recommended annual background exposure to ionising radiation. The mean dose of 13,5 mSv is similar to what other studies have reported.

87% resulted in no action or further imaging. That sounds a bit alarming, as it could be interpreted a lot of CT exams are useless, but that number also represents cases where a blank CT scan prevented surgeries or other invasive procedures.

To further put this in perspective, the National Academy of Science has stated that a 10 mSv dose will result in 1 in a 1000 adults developing cancer in the future. This is very little increase over the background rate of malignancy, but it is still a big deal considering there are more than 7 million paediatric CT scans per year in the US alone.

You really should read the study. The discussion section is excellent and details the possible consequences of the exposure and measures to reduce it. Study lives here:

Injury. 2014 Jan;45(1):164-9. doi: 10.1016/j.injury.2013.06.009. Epub 2013 Jul 8. Radiation from CT scans in paediatric trauma patients: Indications, effective dose, and impact on surgical decisions. Livingston MH, Igric A, Vogt K, Parry N, Merritt NH.

 

 

 

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