The licensee provided notification that a patient received 2 occurrences of a dose less than prescribed when delivering ten fractions of a treatment. Each of the
underdoses were approximately 50% of the 340 Gray prescribed fractional dose. The patient will receive additional dose fractions in order to achieve the written directive total dose. The Radiation Oncologist has notified the patient and attending physician.
- * UPDATE FROM RICHARD MASSOTH TO JOHN KNOKE AT 1826 EST ON 01/31/12 * *
On January 17, 2012 the NRC Operations Center was verbally notified of two Therapeutic Underdose Occurrences discovered by the licensee on January 16 and 17, 2012. These occurrences involved a fractionated Breast High Dose Rate Afterloader (HDR) treatment with a SenoRx Contura multicatheter breast applicator. The first and third delivered treatment fractions were found to be less than 50% of the intended fractional dose. The entire course of the treatment in the written directive included ten equal-dose fractions of 3.4 Gray per fraction for a total dose of 34 Gray to the prescribed treatment site. To correct for the underdose occurrences, two additional treatment fractions were added and the treatment plan was modified to achieve the total dose specified in the written directive.
The licensee now believes that this medical event has also caused an unintended dose to skin outside of the prescribed treatment site, requiring notification under 10CFR35.3045(a)(3). The licensee has performed computer simulation, calculations and physical measurements using TLDs simulating the treatment geometry to model the unintended skin dose. The event delivered an unintended skin dose exceeding at least the skin erythema threshold (2 Gy). The licensee is continuing to monitor the patient response to the skin dose and is working to refine the unintended skin dose estimates. An NRC reactive inspection team is on-site.
Notified R4DO (Jeff Clark) and FSME (Greg Suber)
- * * UPDATE FROM TRACI HOLLINGSHEAD TO HOWIE CROUCH AT 1044 EDT ON 4/12/12 * * *
The licensee confirmed that they agree with their medical consultants' findings that the patient received approximately 2720 rads of unintended skin dose.
Notified R4DO (Gaddy) and FSME (McIntosh).
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.