Daily Bolus of LR: Radiation doses in early pregnancy

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March 17, 2011 by dailybolusoflr

Radiation dose in early pregnancy


mSV or MilliSieverts is a measurement of the effective dose of ionizing radiation to the patient.  It is an average dose and does not reflect age or gender and does not reflect the higher radios-sensitivity of particular tissues.


  Before 2 weeks: > 100 mSv risk for spontaneous abortion (this is a VERY large dose…remember that a pan scan CT for trauma patients gives about 40 mSV)

  Teratogenic effects

  Between 2 and 16-20 weeks at doses of > 50-150 mSv there is evidence of teratogenesis. 

  50mSv is a high dose but in your trauma patient, you can come close. .re-scan the abdomen and pelvis once and you are over 50 mSV

  20 weeks: very unlikely to sustain any teratogenic effects even at higher doses

  Carcinogenic effects

  Always a risk

  Baseline risk of fatal childhood cancer 1 in 2000 (about 50% of childhood cancers are fatal)

  Fetal dose of 50 mSv is associated with a relative risk of 2 …this means that the risk of a fatal childhood cancer would increase to 1 in 1000 (the highest fetal dose from a single imaging study is from abdominal pelvic CT which equals about 15mSv)


For the purposes of the CDC table. .      0.05 Gy is equivalent to 50 mSv

Super complicated stuff. .but good to know there are some resources out there to help you talk to your patients.





Linda Regan, MD FACEP

Program Director, Emergency Medicine Residency

Johns Hopkins Medical Institutions

1830 East Monument Street

Suite 6-100

Baltimore, MD 21287

Office: 410-955-5107

Office: 410-614-9823

Fax: 410-502-5146



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