The following information was provided by the
PA Bureau of Radiation Protection (the Department) via email:
On July 21, 2023, the licensee informed the Department of an underdose incident involving yttrium-90 (Y-90) TheraSpheres. It is reportable as per 10 CFR 35.3045(a)(1). It was determined that 76 percent of the prescribed dose to the target tissue was delivered for the above treatment.
This is believed to have happened for possibly the following reasons: The spheres were attached to the bottom / interior portion of the septum and remained there even through 4 flushes of the system; There was clumping of spheres in the microcatheter connector, which did not clog the lines, that remained in the microcatheter connector.
Possible reasons for these theories or reasons for the above theories are, there was no contamination in the room, or interior / exterior of box. The required alarming Rados personal dosimeter on the back of the box read zero as expected after the original 3 flushes. The authorized user (AU) had no indication from pushing the line that anything was wrong with the flow and in total 4 flushes went into the patient with no problem. All procedures and policies were followed, and this was directly observed by the Radiation Safety Officer (RSO) and the Boston Scientific Corporation, Incorporated (BSCI) company rep who was in the room.
It was observed on the optional, additional, personal dosimeter that was used on the steel arm coming from the box, that the dose rate did not decrease as expected after the original first 3 flushes. The patient and referring physician have been informed. The Department is currently in contact with the licensee and will update this event as soon as more information is provided.
The cause of the event is unknown at this time. The Department will perform a reactive inspection. More information will be provided as received.
- * * UPDATE FROM JOHN CHIPPO TO DONALD NORWOOD 1007 EDT ON 7/25/2023 * * *
The source was 1.09 GBq of Yttrium 90 TheraSpheres (Lot # 2399334, vial # 8). The patient was prescribed 120 Gy, but it is calculated they received 91.4 Gy. The material was collected in the standard waste container. No one other that the patient received any dose.
Notified R1DO (Biickett) and NMSS Events Notification email group.
Pennsylvania Event Report ID Number: PA230019
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.