The following information was provided by the licensee via email:
During an SIR [Selective Internal Radiation] Spheres treatment on November 17, 2022, a patient was to receive 10.8 milliCuries of Y-90 [Yttrium-90]. A measurement of the residue radiological waste from the procedure indicated that the patient only received 38 percent of the intended dose or 4.33 milliCuries. The total dose delivered differs from the prescribed dose by 20 percent or more.
The doctor drew up a dose of 11.4 milliCuries for the procedure. Static readings on the vial averaged 0.205 mR/hr. Post procedure readings averaged 0.127 mR/hr. These readings resulted in the fraction delivered of 38 percent or a total of 4.33 milliCuries. Corrective action is pending.
- * * UPDATE ON 12/2/2022 AT 1257 EST FROM THE DEFENSE HEALTH AGENCY TO BILL GOTT * * *
Following administration of Y-90 Sir Spheres on November 17, 2022, the treatment team determined that the faction of the assayed dose delivered to the patient was only 38 percent. The remaining 62 percent of the assayed dose of 11.4 mCi remained within the delivery system. This represents a delivery of 40 percent of the prescribed dose of 10.8 mCi. The microcatheter used was size 2.4F, which was appropriate for the clinical situation. The vascular access to the treatment location was unusually torturous. Two representatives from Sirtex advised during the procedure, rotating out part way through the procedure so one was present at all times, with no noted deviations from the recommended protocols.
The event likely occurred due to microsphere blockage in the microcatheter, resulting from a torturous path to the delivery point required by the patient's vascular anatomy. Sirtex indicated that the spheres must have attached to the catheter walls due to a torturous path (excessive bends in the line).
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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.