EN Revision Imported Date : 8/17/2020
EN Revision Text: AGREEMENT STATE REPORT - MEDICAL EVENT
The following was received via email:
"On 6/30/20 microspheres were injected in the patient [intended target of Hepatic Segments 4 through 8] at the vessel branch point with the intention of targeting both the right hepatic artery (RHA) and the middle hepatic artery (MHA). However, post-therapy imaging demonstrates that radiotracer was preferentially deposited along the MHA distribution. This is attributed to unforeseeable clumping of microspheres at the origin of the RHA, such that a majority of the microspheres were preferentially injected into MHA. As such, microspheres were predominantly deposited in the extrahepatic lymph node as well as an unexpected pancreaticoduodenal lymph node. Deposition in this second node can be attributed to additional unintended reflux into a third branching vessel upstream from the RHA and MHA, and further supports the assertion flow into the RHA was hindered by the clumping of microsphere particles. Ultimately, SPECT-CT image analysis suggests no more than approximately 40 percent of the therapy dose was deposited within the liver (as detailed below).
"It is estimated the following activity distribution from post-treatment imaging: At most, approximately 40 percent of the administered activity appears to be within the liver, with the other 60 percent being in extrahepatic tissue (e.g. lymph nodes). This breakdown should be considered approximate, as these images are not scatter corrected.
"From pre-treatment macro aggregated albumin (MAA) imaging, it appears that 84 percent of the administered activity was expected to be delivered to the liver, and 16 percent was expected to shunted to the nodes. Overall, this indicates that approximately 53 percent less activity than what was intended reached the liver. There is uncertainty in this estimate.
"The dose to extrahepatic tissue (lymph nodes) differs from what was intended/expected by more than 50 Rem (0.5 Gy)."
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.
* * * RETRACTION ON 8/14/2020 AT 1131 EDT FROM RANDAL DAHLIN TO KERBY SCALES * * *
The following retraction was received from the state of Iowa via email:
"On July 6, 2020 Iowa reported a potential medical event at the University of Iowa (License number 0037-1-52-AAB) involving Yttrium-90 (Y-90) microspheres. This potential medical event occurred on June 30, 2020 and was discovered by the licensee on July 1, 2020 during analysis of post therapy SPECT/CT imaging. This event was reported to the state on July 2, 2020 after staff working hours. Iowa Department of Public Health (IDPH) Radioactive Materials Program (RAM) staff became aware of the potential medical event on July 6, 2020 after the holiday weekend.
"IDPH staff conducted a reactive inspection at the University of Iowa on July 8, 2020 to interview university staff involved in the procedure and the university radiation safety officer, review the written directive for the Y-90 procedure and review fluoroscopic images of placement of the catheter in the right hepatic artery. IDPH staff determined that the university used due diligence in following their policies and procedures for Y-90 administrations and manufacturer's instructions and no violations were noted.
"The university followed up with a written report on July 16, 2020 which determined that the unintended dose to the lymph nodes was due to shunting through a pathway or bypass due to patient vasculature. A review of the NRC licensing guidance for Y-90 microspheres dated March 20, 2020 Revision 10.1 revealed that unintended doses to tissue or organs during a Y-90 procedure due to shunting is not considered a reportable medical event.
"IDPH program staff had a meeting with NRC Region III staff on Wednesday, August 12, 2020 to discuss this potential medical event. Region III staff agreed with IDPH that this unintended dose was due to shunting and therefore not a reportable medical event.
"Therefore Iowa is retracting event number 54764."
Notified R3DO (Pelke) and NMSS Events (email).