Thyroid shield for fluoroscopy: no federal rule we read requires one, but your state or facility may
Key takeaways
- 21 CFR 1020.32 never mentions aprons, thyroid shields, gloves or drapes.
- 10 CFR 20.1201 sets dose limits, including 500 mSv (50 rem) a year to any organ except the lens.
- Your state or facility may require one. We name no state rule here, so ask your radiation safety officer.
- Sherer advises a 0.5 mm Pb shield for staff assisting in fluoroscopy, especially close to the patient. Bontrager calls it optional, with a small effective dose reduction.
- The patient gonadal and fetal shielding statements don't apply to the protection you wear.
No federal rule we read requires you to wear a thyroid shield for fluoroscopy, and none says one must be available. Your state or your facility may require it. Check with your radiation safety officer, and wear one when you’re close to the patient.
What do the federal rules say?
21 CFR 1020.32 is an FDA performance standard for fluoroscopic equipment: barriers, field limits, air kerma rates and displays. We searched the whole of Part 1020. The words apron, thyroid, glove and drape don’t appear.
An earlier version of this page quoted “21 CFR 1020.32(b)(4)” as saying protective devices “shall be available”. That text doesn’t exist. Real (b)(4) covers fluoroscopy with circular image receptors. If another study source repeats that quote, don’t rely on it.
10 CFR Part 20 sets dose limits for NRC licensees. It has no thyroid shield rule. The NRC also says it doesn’t regulate the use of x-ray equipment for medical procedures. These are the NRC’s limits. For an exam on or after March 1, 2027, the 2027 outline cites NCRP Report 180 instead, so read the lens section of our Radiation Protection guide before you memorize the lens number:
| Limit in 10 CFR 20.1201 | Per year |
|---|---|
| Total effective dose equivalent | 50 mSv (5 rem) |
| Any organ or tissue except the lens, which includes the thyroid | 500 mSv (50 rem) |
| Lens of the eye | 150 mSv (15 rem) |
| Skin or extremity | 500 mSv (50 rem) |
So who decides?
We found no source that settles this for thyroid shields. Your state or your facility may set a rule, and Bontrager says the facility should provide a shield for use at the worker’s option. We didn’t review every state’s rules, so we name none here. Ask your radiation safety officer what applies.
What should you actually do?
The textbooks don’t agree. Sherer’s textbook says staff assisting in fluoroscopy should wear a thyroid shield of 0.5 mm lead equivalent, especially when standing close to the patient. The same chapter advises one for general fluoroscopy and special procedures. An earlier chapter’s summary goes further and says they’re required during high-level procedures, but it names no regulator. Sherer also calls shields essential for everyone involved in C-arm work. Bontrager says a thyroid shield isn’t required for people taking part in fluoroscopy. It says the facility should make one available at the worker’s option, that the overall reduction in effective dose is small, and that one is recommended for someone approaching a significant fraction of the dose limit. We follow the regulations on what is legally required and treat both books as practice advice.
Our judgment: wear one whenever you can’t stay back from the table. Sherer says the unprotected head and neck get 10 to 20 times the exposure of the shielded trunk. Keep your dosimeter at the collar, outside the shield and apron. Our two-badge page shows where each one goes.
What do the AAPM, ARRT and ASRT statements change?
Nothing about what you wear. AAPM’s position statement and the ASRT and ARRT statements deal with gonadal and fetal shields on patients. None of them mentions the thyroid. Follow your facility’s protocol for patients.
What does the ARRT outline list?
The ARRT® 2027 outline lists protective devices under personnel protection, with aprons and barriers as examples. It cites NCRP Report 102 for minimum lead equivalents and NCRP Report 102 and 21 CFR for fluoroscopy guidelines. It doesn’t name thyroid shields, and our text search of a public copy of NCRP Report 102 found no thyroid shield figure. ARRT doesn’t say how an item would word this, so we won’t give you an exam answer.
For apron numbers, read lead apron attenuation. The Radiation Protection guide has the full device table, and the Radiation Protection practice set lets you drill it.
Frequently asked questions
Does 21 CFR 1020.32 require lead aprons or thyroid shields?
No. It sets performance standards for fluoroscopic equipment. The section doesn't mention aprons, thyroid shields, gloves or drapes. Paragraph (b)(4) is about fluoroscopy with circular image receptors.
What is the occupational dose limit for the thyroid?
10 CFR 20.1201 has no limit named for the thyroid. It's covered by the limit for any individual organ or tissue except the lens: 500 mSv (50 rem) a year. The 50 mSv (5 rem) total effective dose equivalent limit also applies.
Do the AAPM and ASRT shielding statements mean I can skip my thyroid shield?
No. Those statements cover gonadal and fetal shields on patients. They don't address the protection staff wear.
What lead equivalent should a thyroid shield have?
Sherer gives a minimum of 0.5 mm lead equivalent, and Bontrager's table lists the same. ARRT's outline points to NCRP Report 102 for minimum lead equivalents. We read a public copy of that report: it sets 0.5 mm for fluoroscopy aprons, and our text search found no thyroid shield figure.
Sources
Found an error? Email [email protected] with the page and the source.
- 21 CFR 1020.32, Fluoroscopic equipment Regulation
- 10 CFR 20.1201, Occupational dose limits for adults Regulation
- NRC Regulatory Guide 8.40, July 2010 Guidance
- ARRT Radiography Examination Content Specifications, effective March 1, 2027 (repo copy) Official
- NCRP Report 102, Medical X-Ray, Electron Beam and Gamma-Ray Protection for Energies Up to 50 MeV, 1989, Section 3.3.4(p) (public copy at law.resource.org) Official
- AAPM Position Statement on Patient Gonadal and Fetal Shielding, PS 8-A Official
- ARRT, Statement on Gonadal and Fetal Shielding, R.T. Update, Spring 2021 Official
- ASRT Statement on Fetal and Gonadal Shielding, January 12, 2021 Official
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