[Intl_DxMedPhys] [EXTERNAL] Radiotoxicity testing

Thu Jun 5 16:21:30 EDT 2025

In Canada there are regulatory documents covering which isotopes require
bioassay and the time frequency, and how they are to be performed.  Not
only that, but the biosassay requirements are listed as conditions on the
licence.  So all they have to do is read their licence.  For I-131, the
bioassay is done via thyroid counting, not urine.  The required urine
bioassays are for isotopes not usually used by NM techs.  For example
Tritium, Uranium etc.  So for instance if there is DU shielding , then
urine counting and wipe testing are licence conditions.
On the other hand, there is nothing stopping you from doing urine bioassays
to help allay staff fear.  When I was RSO of a major downtown hospital in
Toronto, we did urine testing of the techs for Tc-99m when we started using
aerosol for VQ scanning of the lungs.  Nothing was found.  When I was the
Corporate RSO at Ontario Ontario Power Generation, routine urine samples
were collected from all employees for tritium as tritium is common in the
CANDU reactors.
So the best way to check is just to read the licence.  You can then call
the CNSC licence compliance officer for the site if you have any questions.
 Spencer M Fisher

On Thu, Jun 5, 2025 at 3:45 PM Timmerman, Michael via
Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list at lists.osu.edu> wrote:

> It looks like you are in Canada but I will share the regulatory
> requirements here in the US, which may be helpful. The US NRC has a
> regulatory guide that covers bioassay for radioiodine. In most cases, I
> would only recommend bioassay if there
>
> It looks like you are in Canada but I will share the regulatory
> requirements here in the US, which may be helpful.
>
>
>
> The US NRC has a regulatory guide that covers bioassay for radioiodine. In
> most cases, I would only recommend bioassay if there is a suspected
> exposure, such as an I-131 capsule breaking open. The NRC considers
> capsules as sealed sources for the sake of bioassay requirements and the
> risk to staff is minimal if the capsule is not broken. I did work with a
> site in the past that administered liquid radioiodine to patients who could
> not swallow a capsule; however, the activities used (imaging procedures
> only) fell well below the NRC limits requiring bioassay. We are mainly
> concerned with people handling unsealed airborne/volatile radioiodine,
> which is not common in the medical setting nowadays; I-131 capsules, for
> example, are formulated to be way less volatile than they used to be. This
> is directly from the below regulatory guide: (3) Capsules (such as gelatin
> capsules given to patients for diagnostic tests) may be considered to
> contain the iodine in sealed form, and bioassay would not be necessary
> unless a capsule were inadvertently opened (e.g., dropped and crushed).
>
>
>
> https://urldefense.com/v3/__https://www.nrc.gov/docs/ML1406/ML14064A060.pdf__;!!KGKeukY!1Es-pJolWrXs9qAP9c-6qDeMsdxP-PNvGuHNYT1L7FkPKOad11KiKKnUJ0jJVQY_Iz557OxVdPTMSYvAqY3yjHzdj2yhoecOaoO7o3Ko1g$ 
> <https://urldefense.com/v3/__https://www.nrc.gov/docs/ML1406/ML14064A060.pdf__;!!KGKeukY!1ESpz4uV1rSR-_UfmqcnZfq1ctWqRFluRtV2TYECbRPCzUbRVfWU0PKPV0a7wLnBRJHJwHVVuZ29WXVAVeF88buDF2Q2_9_cWuYSqsejQlLU0GFUMmslZb3S$>
>
>
>
> The US NRC also has regulations covering when internal monitoring is
> required and this is based on the annual limit on intake (ALI) for the
> radioisotope in question. Anyone likely to exceed 10% of the ALI must be
> monitored for internal occupational dose. It is extremely unlikely for a
> nuclear medicine technologist to exceed these levels unless something goes
> horribly awry during an administration (or several). For example, the ALI
> for Tc-99m is 80 mCi by oral ingestion or 200 mCi by inhalation. For
> Lu-177, we are looking at 2 mCi by oral ingestion or inhalation.
> Radioiodine limits are a lot lower (in the uCi range for I-125 and I-131)
> but again, the likelihood is very low when using capsules. We see “likely
> to exceed” a lot in NRC regulations, which requires us to make an educated
> decision on what “likely” means.
>
>
>
>
> https://urldefense.com/v3/__https://www.nrc.gov/reading-rm/doc-collections/cfr/part020/part020-1502.html__;!!KGKeukY!1Es-pJolWrXs9qAP9c-6qDeMsdxP-PNvGuHNYT1L7FkPKOad11KiKKnUJ0jJVQY_Iz557OxVdPTMSYvAqY3yjHzdj2yhoecOaoO2fCXiwQ$ 
> <https://urldefense.com/v3/__https://www.nrc.gov/reading-rm/doc-collections/cfr/part020/part020-1502.html__;!!KGKeukY!1ESpz4uV1rSR-_UfmqcnZfq1ctWqRFluRtV2TYECbRPCzUbRVfWU0PKPV0a7wLnBRJHJwHVVuZ29WXVAVeF88buDF2Q2_9_cWuYSqsejQlLU0GFUMokebqvS$>
>
>
>
> I’ve never needed to perform bioassays in my previous roles as RSO. It’s
> not impossible but I would guess it is rather unlikely nowadays. Interested
> if others have any thoughts on this topic as well.
>
>
>
> Best,
>
>
>
> Mike
> ________________________________________
>
> *Mike Timmerman, MS, DABR*
>
>
> *Diagnostic Medical Physicist Sanford Health – Sioux Falls Region *Mobile:
> (541) 213-1075
>
> [image: Icon Description automatically generated with medium confidence]
>
>
>
> *From:* Intl_dxmedphys_wd_osu_list
> <intl_dxmedphys_wd_osu_list-bounces+michael.timmerman=
> sanfordhealth.org at lists.osu.edu> *On Behalf Of *Idris Elbakri via
> Intl_dxmedphys_wd_osu_list
> *Sent:* Thursday, June 5, 2025 5:36 AM
> *To:* intl_dxmedphys_wd_osu_list at lists.osu.edu
> *Subject:* [EXTERNAL] [Intl_DxMedPhys] Radiotoxicity testing
>
>
>
> Dear colleagues, I received an inquiry about radiotoxicity urine testing
> for nuc. medicine technologists. The question is if/when should those be
> required, if at all. As I am not a NM expert, I am reaching out to see if
> someone on this list
>
>
>
> Dear colleagues,
>
>
>
> I received an inquiry about radiotoxicity urine testing for nuc. medicine
> technologists. The question is if/when should those be required, if at all.
>
>
>
> As I am not a NM expert, I am reaching out to see if someone on this list
> can provide some insights. Thanks in advance for your responses.
>
>
>
> Idris
>
>
>
> Dr. Idris Elbakri
>
> CANQAP LTD
>
> https://urldefense.com/v3/__http://www.canqap.com__;!!KGKeukY!1Es-pJolWrXs9qAP9c-6qDeMsdxP-PNvGuHNYT1L7FkPKOad11KiKKnUJ0jJVQY_Iz557OxVdPTMSYvAqY3yjHzdj2yhoecOaoOkW7Xesw$ 
> <https://urldefense.com/v3/__http:/www.canqap.com__;!!KGKeukY!yTQkSO5dfACjQkULfShIlpIeyU23-Zc7UdMAflCNrEt8CTkIo-5R8uPFKXyYnDNyEtM5HyuzVH7vLXWOroD172Aa0Fx4ZyeZXjy0BQ$>
>
>
>
>
>
>
>
>
> -----------------------------------------------------------------------
> Confidentiality Notice: This e-mail message, including any attachments,
> is for the sole use of the intended recipient(s) and may contain
> privileged and confidential information. Any unauthorized review, use,
> disclosure or distribution is prohibited. If you are not
> the intended recipient, please contact the sender by reply e-mail and
> destroy
> all copies of the original message.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.osu.edu/mailman/private/intl_dxmedphys_wd_osu_list/attachments/20250605/ff5c71a1/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.png
Type: image/png
Size: 13296 bytes
Desc: not available
URL: <https://lists.osu.edu/mailman/private/intl_dxmedphys_wd_osu_list/attachments/20250605/ff5c71a1/attachment.png>