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Three Part Question

In [acute trauma patients] does [radiation exposure from diagnostic imaging] increase the [risk of cancer]?

Clinical Scenario

A 24 year old male pateint presents to the emergency department after a high speed motor vehicle accident. Patient was intubated in the field has a GCS of 7T, multiple lacerations and obvious deformity of his RLE. While ordering diagnostic xrays, you wonder about the radiation exposure to the patient.

Search Strategy

Medline 1950-05/07 using OVID interface, Cochrane Library 2007, Pubmed clinical queries.
[(exp radiation dosage/) AND (trauma.mp). LIMIT to human and English

Search Outcome

84 papers were found of which 82 papers were irrelevent to the study question or of insufficient quality for inclusion. Two papers were prospective clinical studies that actually measured cumulative radiation exposure in trauma patients.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Ott, M. et al. June 2006 USA	224 Priority One trauma patients between September 2004 and July 2005; 167 adult and 57 pediatrics.	Prospective Cohort	The median level of radiation was 68 MREM. Average annueal MREM is 100 MREM. A significant increase was found in those patients with orthopedic injuries, increased severity score, or length of stay.	In comparison with the general population, trauam patients are exposed to elevated doses of radiation, but below extrapolated levels that are a concern for causing cancer.	Study bracelets on wrist may have underestimated core exposure dosage.
Tien, H. et al 2007 Canada	291 trauma patients arriving from scene of injury from June 2004 - March 2005	Prospective cohort study	Patients received an average of 4.9 CT scans and 13 plain films.	Total effective dose for study patients was 22.7 mSv. Average background radiation in 1 year is 2.4 mSv. Thyroid doses were much higher at 58.5 mSV,. with 22% pts having a mean of over 100 mSv. An average of 190 Cancer deaths would arise from the study population compared with the general population.	The Hospital added a CT radiation optimization package to the CT machines 6 weeks into the study, which altered the amount of radiation emitted by the scanner. This upgrade decreased radiation emmission from the CT. Only 291/443 possible study participants were enrolled in the study. Of the 291, 87 patients lost 1 or more dosimeters and authors had to use chart estimation to determine the mean radiation dose.

Comment(s)

Both studies found similar results that trauma patients during their hospital stay are exposed to radiation doses well over the yearly dose for the general population. The study by Ott el al likely had decreased comparative levels of radiation due to placement of the dosimeter on the wrist and not on the core. The Tien study did fail to enroll almost 1/3 of patients. However they did compare the missed patient characteristics with study group and found minimal difference. Estimating cancer death from radiation dose is a significant extrapolation, however both studies show impressive cummulative doses of radiation for trauma patients.

Clinical Bottom Line

Trauma patients undergo significant amounts of radiation during their hospital stay, most of which is from CT scans. The clinical magnitude of this radiation is not completely elucidated, howevere current extrapolations estimate an excess cancer death of 190/100,000 in this group. Further study needs to be done to evaluate the risk/benefit of this diagnostic imaging.

References

1. Ott M., McAlister J., Vanderkolk, W., Goldsmith, A., Radiation Exposure in Trauma Patients The Journal of Trauma June 2006;61:607-610
2. Tien, H.C., et al Radiation Exposure from Diagnostic Imaging in Severely Injured Trauma Patients The Journal of Trauma 2007;62:151-156