A patient undergoing Gamma Knife treatment received less than the prescribed dose in the eighth of eight planned treatments. The undertreatment exceeded 50% of the planned treatment dose for the final fractional treatment (only approximately 12 rads of the prescribed approximately 162 rads for the final fractional dose was administered).
The final treatment was terminated approximately 15 seconds into the planned 3.5 minute treatment due to apparent pain on the part of the patient. Upon investigation, it was determined that the head immobilizing bracket was not fully secured. Only approximately 12 rads dose had been administered in the approximately 15 seconds before the treatment was terminated. The planned total treatment dose was 1300 rads. Approximately 1150 rads were administered in the eight treatments.
The licensee reported they likely will not give the patient the remaining 150 rads of the planned treatment.
CA Event No.: 061810
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.