The following is a summary of information provided by the licensee via phone:
A TheraSphere treatment comprised of three fractions was planned to be administered to the patient's liver. The first fraction was planned to be 1.1 GBq Y-90, the second fraction 1.1 GBq Y-90, and the third fraction 1.46 GBq Y-90.
When the treatment was administered, the third fraction (actual activity 1.48 GBq Y-90) was administered first, in place of the intended first fraction. The second fraction was administered as planned. The error was discovered when the vial containing the third fraction was found to have already been used. The treatment plan was then revised to use the remaining first fraction vial (actual activity 1.02 GBq).
All fractions were administered to the patient's liver as planned and the total dose was in accordance with the treatment plan.
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.