The following report was received from the State of
Kansas via email:
Yesterday afternoon [the State of Kansas] was contacted by [the licensee's], RSO [Radiation Safety Officer] for KU Hospital Authority lic# 18-C801, to report a medical event. On the morning of 9/29/15, a Thera-spheres Y-90 therapy procedure was found to have underdosed the patient by 36%. The details are as follows:
A RADose RAD 60R personal electronic dosimeter is attached to the plexiglass 'box' which holds the vial containing the Y-90 Thera-spheres during the procedure. This dosimeter is the only method of detection to ensure that all of the Y-90 material is placed within the patient. In comparison, the Sir-sphere, similar material and procedure, utilizes a contrast to better ensure material is where it's supposed to be.
Prior to the procedure, the dosimeter was checked for current calibration and source checked and found to be satisfactory including low battery indicator not active. During this pre-procedure check, the dosimeter exhibited fluctuating readings. A backup dosimeter of the same make and model was searched for but could not be located. The dosimeter was then re-checked and the fluctuations could not be duplicated, thus it was decided to utilize the dosimeter for the procedure. The Y-90 procedure was then completed, with the dosimeter reading at levels that indicated the required Y-90 had been placed within the patient. At this point, the 'waste' from the procedure i.e. vials, tubing, pads is taken back to the hot lab and surveyed to calculate the remaining Y-90. It was discovered that 36% still remained and that the patient did not receive the entire prescribed dose. It was determined that enough of the Y-90 had been administered to the patient to receive a satisfactory therapeutic dose thus another procedure would not be necessary.
Exposure to staff was also determined to be negligible due to the nature of the material/shielding/remaining concentration. The RSO stated that the dosimeter was again rechecked and the low battery indicator was active during the check. The RSO made the preliminary assessment that the dosimeter was possibly functioning just above the 'cutoff' point of low battery.
The licensee stated that a detailed report is in process and will be submitted within the required time parameters.
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.