The following was received from the State of
Washington via email:
Patient was under treated with Y-90 SIR-Spheres Microspheres. Prescribed dose was 24.59 mCi. Patient was treated with 8.9 mCi.
Background: SIR-Spheres Microspheres Activity Calculator determined a treatment dose of 0.91 GBq (24.59 mCi). Written Directive was signed for 0.91 GBq. Prescribed dose was entered into the Treatment Worksheet as 0.91 mCi. Dose activity delivered to the interventional radiology procedure room (Dose In-Vial) was recorded as 0.96 mCi.
Analysis: Radioactivity units of measurement varied between Written Directive and Treatment Worksheet. Radioactivity activity readings from the dose calibrator were recorded with a systematic error. Calibrator reading multiplication factor(x10) was not applied. Therefore, the vial pre-dispense Y-90 activity reading of 8.62 mCi should have been recorded as 86.2 mCi. Dose activity delivered to the IR procedure room was in fact 9.60 mCi rather than 0.96 mCi.
Y-90 SIR-Spheres treatment on 3/30/2018 was incomplete because the prescribed 0.91 GBq prescribed dose was not administered. Standard post-procedure verification check identified the under treatment. The patient was informed by the prescribing physician and scheduled for a second treatment on 4/6/2018. The second Y-90 SIR-Spheres treatment was performed on 4/6/2018 and the remaining dose was administered to complete administration of the prescribed 0.91 GBq.
Washington State Incident Number: WA-18-010.
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.