* If CT angiography is considered technically inadequate, Doppler ultrasound of the legs should be performed or CT angiography should be repeated. ** If the V/Q scintigraphy is nondiagnostic, CT angiography should be performed.
* If CT angiography is considered technically inadequate, Doppler ultrasound of the legs should be performed or CT angiography should be repeated. ** If the V/Q scintigraphy is nondiagnostic, CT angiography should be performed.
Examination | Estimated fetal dose (mGy) |
---|---|
Conventional radiography | |
Cervical spine (anteroposterior, lateral), extremities, thorax (posteroanterior, lateral), thoracic spine | < 0.003 |
Lumbar spine (anteroposterior, lateral) | 1 |
Abdomen (anteroposterior) | < 3 |
CT | |
Head | 0 |
Thorax (routine), thorax (CT angiography for suspected PTE) | 0.2 |
Abdomen | 4 |
Abdomen and pelvis | 25 |
CT angiography of the aorta | 34 |
Period (age) | Dose / deterministic effects | ||||
---|---|---|---|---|---|
Menstrual/gestational | Embryonic | < 50 mGy | 50-100 mGy | > 100 mGy | |
0-2 weeks | Prior to conception | None | None | None | |
3-4 weeks | 1-2 weeks | None | Probably none | Possible spontaneous abortion | |
5-10 weeks | 3-8 weeks | None | Potential effects uncertain and too subtle to be clinically detectable |
Possible malformations, increasing in probability as doses increase |
|
11-17 weeks | 9-15 weeks | None | Potential effects uncertain and too subtle to be clinically detectable |
Risk of cognitive deficits becoming more frequent and more severe as doses increase |
|
18-27 weeks | 16-25 weeks | None | None | Deficits in intelligence not detectable at diagnostic doses |
|
> 27 weeks | > 25 weeks | None | None | None are applicable to diagnostic medicine |