Event Notification Report for April 30, 2024

STUCK SHUTTER

The following information was provided by the licensee via phone:

The radiation safety officer (RSO) attempted to actuate air to close the shutter on a 2003 Vega source holder, model SH-F2, serial number 2791CG, containing 500 mCi of Cs-137. The source turns into the source holder like it normally does, however, radiation levels are the same as when the shutter is open. The RSO is in contact with Vega to schedule a technician to service the shutter. The shutter is normally in the open position and there has been no additional exposure to personnel or the public due to the position of the shutter.

EN Revision Imported Date: 5/31/2024

EN Revision Text: AGREEMENT STATE REPORT - MEDICAL EVENT

The following was provided by the Illinois Emergency Management Agency (the Agency) via email:

"On April 30, 2024, the Agency was notified by Northwestern Memorial HealthCare's radiation safety officer of an yttrium-90 (Y-90) TheraSphere underdose. There were no adverse patient impacts reported, and the treatment is scheduled to be repeated the following week. The initial information indicated an underdose of Y-90 TheraSpheres of near 100 percent. Additional information is forthcoming, and Agency staff will be on-site to perform a reactive inspection on May 5, 2024. Updates will be made when available."

* * * UPDATE ON 05/30/2024 AT 1105 EDT FROM WHITNEY COX TO JOSUE RAMIREZ * * *

The following information was provided by the Illinois Emergency Management Agency (the Agency) via email:

"Based on the May 2, 2024, reactive investigation, agency inspectors determined that this case qualifies as a medical event under 335.1080(a)(1). The authorized user (AU) stated that no negative health effects were expected for the patient and that the patient will be retreated in the future. The patient and referring physician were notified of the event within 24 hours as required. Agency inspectors determined the potential root cause as the clumping of microspheres due to the overtightening of the tuohy luer lock. This matter may be considered closed pending further information."

Notified R3DO (Szwarc) and NMSS Events Notifications (Email).

IL Event Number: IL240009

A Medical Event may indicate potential problems in a medical facility's use of radioactive materials. It does not necessarily result in harm to the patient.

EN Revision Imported Date: 5/13/2024

EN Revision Text: AGREEMENT STATE REPORT - OVEREXPOSURE TO AN EMBRYO / FETUS

The following information was obtained from the Illinois Emergency Management Agency (the Agency) via email:

"The Agency was contacted on April 30, 2024, by Advocate Illinois Masonic Medical Center in Chicago, IL, to advise a patient was administered a therapeutic dose of iodine-131 on March 7, 2024, and was confirmed pregnant on April 29, 2024. The licensee estimates the pregnancy began 3-7 days after the iodine administration. Negative pregnancy test results were confirmed prior to the administration. Both the patient and the referring physician were notified on April 29, 2024. Using dose modeling [published by the International Commission on Radiological Protection] (ICRP-88) methodology, and assuming conception was 3 days post-administration, the Agency estimates dose to the embryo/fetus over the term of the pregnancy to be 19.8 rem. This is based on an effective half-life of 5.5 days over the 3 days from administration. The patient has had a thyroidectomy which complicates the use of available biokinetic models, but likely also alters the effective half-life. The licensee is researching to determine an appropriate value for the effective half-life (which may range down to 14.4 hours and result in a 900 mrem effective dose).

"Agency inspectors will conduct a reactionary inspection, and this report will be updated as additional information becomes available."

IL Report Number: IL240010

* * * RETRACTION ON 5/10/24 AT 1630 EDT FROM GARY FORSEE TO TENISHA MEADOWS * * *

The following was received from the Illinois Emergency Management Agency (the Agency) via email:

"Agency inspectors performed a reactive inspection on 5/3/24. The licensee and involved physicians performed a detailed literature and patient review (remnant thyroid) and concluded 9.4 to 56.4 hours was the range of applicable effective half-lives. The licensee asserts, given the patient's sex, age, recombinant human thyroid stimulating hormone (rhTSH) treatment status, weight, renal function and disease burden; that 14.4 hours is the appropriate effective half-life to utilize. Empirical calculation using whole body counts was no longer viable due to decay/clearance. Based on a review of available literature and previous incidents, the Agency would concur that 14.4 hours is an appropriate value for a patient having undergone a thyroidectomy. Estimates on the date of conception relative to the date of administration were confirmed by the licensee and a range of 3/10/24 to 3/18/24 provided. The 3/10/24 date was utilized (as a means of conservation) which results in a 0.9 rem (9 mSv) dose to the embryo using the afore mentioned ICRP 88 methodology. The licensee submitted their written report and assessment on 5/10/24. The licensee consulted the I-131 package insert for tissue-specific dose conversion factors. Consistent with ICRP 88, the dose to the patient's uterus was used as representative of that to the embryo. While relying on dose conversion factors differing from those in ICRP 88, the licensee calculated a 5.19 mSv embryonic exposure. Notwithstanding the variation between the licensee's 5.2 mSv vs. the Agency's 9 mSv dose estimate; the dose falls beneath the reportable criteria."

Notified R3DO (Ruiz), NMSS Regional Coordinator (Riveria-Capella), and NMSS Events Notification via email.