Fetal Radiation Dose Estimates

 

 
APPROXIMATE FETAL DOSES CONSEQUENTIAL TO SELECTED PLAIN FILM, FLUOROSCOPIC AND CT PROCEDURES

Radiation doses to the fetus for selected procedures are tabulated below. The doses are expressed in millirads. Unlike nuclear medicine studies, radiographic studies are subject to wide variablity in operator-dependent parameters. These parameters include skin entrance dose (which depends upon KVP and MAS settings), beam filtration, tube output roentgens per minute), total fluroscopic "beam-on" time and the number and location of "spot" films taken. Because of the uncertainties in these parameters, these fetal dose values are considered to be approximations only. The parameter values used in caculating these doses are in part derived from U.S. national averages as compiled in NCRP Report 100, and in part from experience with actual Duke University studies. Accordingly, these dose values should be used only as a guide to determining a subsequent course of action, and not as "hard and fast" numbers.

The fetal doses appear in colored cells. The colors reflect the degree of risk to the fetus associated with the study. Procedures with "green" cells generally carry zero to minimal risk of harm. Studies with "yellow" cells incur doses for which the risk is possibly increased, but for which little supporting data is available. Studies with "red" cells can incur doses within the range of those associated with teratogenicity, mental retardation and secondary childhood cancers. For these studies, a more accurate dose reconstruction should be obtained.

Procedure

Dose (millirads)

Comments

Abdomen

240

Abdominal CT (with and without contrast)

2,000

Assumes fetus in field of view. Fetal dose will decrease with increasing gestational age.

Abdominal CT (without contrast)

1,000

Assumes fetus in field of view. Fetal dose will decrease with increasing gestational age.

Cardiac catheterization (with pelvic fluoroscopy)

1,300

Assumes 60 minutes fluoro time (50% shallow RAO, 25% AP, 25% shallow LAO), worst-case tube output and filtration, two minutes fluoro time for sheath placement. Range could be 400 - 3,100 mrad depending upon skill of operator.

Cardiac catheterization (without pelvic fluoroscopy)

100

Assumes 60 minutes fluoro time (50% shallow RAO, 25% AP, 25% shallow LAO), worst-case tube output and filtration

Cervical spine

< 1

Assumes gonadal shielding; may be somewhat higher if not provided.

Chest

< 1

Assumes gonadal shielding; may be somewhat higher if not provided.

Chest CT

< 10

Assumes gonadal shielding; may be somewhat higher if not provided.

Dental

< 1

Assumes gonadal shielding; may be somewhat higher if not provided.

Head CT

< 10

Assumes gonadal shielding; may be somewhat higher if not provided.

Hip

130

Intravenous pyelogram (IVP)

730

KUB

240

Lumbar spine

340

Pelvic CT (with and without contrast)

2,000

Assumes fetus in field of view. Fetal dose will decrease with increasing gestational age.

Pelvic CT (without contrast)

1,000

Assumes fetus in field of view. Fetal dose will decrease with increasing gestational age.

Pelvis

170

Ribs

< 1

Assumes gonadal shielding; may be somewhat higher if not provided.

Thoracic spine

< 1

Assumes gonadal shielding; may be somewhat higher if not provided.

Upper GI with small-bowel follow-through

3,900

Assumes five minutes fluorooscopy time, 4 thoraco-abdominal spots, 1 abdominal spot, I pelvic spot. Depending on parameters, range is 800 - 6,000 millirads

Voiding cystourethrogram

4,600

Assumes five minutes fluoroscopy time, 22 pelvic/abdominal spot films. Will be highly variable based on skill of operator.

Back to the Fetal Dose Home Page

Back to Health Physics Home Page