BEUDAMED
    FDA Adverse Event Malfunction Summary report: N

    MRIDIAN LINAC

    MDR report key: 8541345 · Received April 23, 2019

    Report

    Report Number
    3011233554-2019-00004
    Event Type
    Malfunction
    Date Received
    April 23, 2019
    Date of Event
    April 2, 2019
    Report Date
    April 22, 2019
    Manufacturer
    VIEWRAY, INC.
    Product Code
    IYE
    PMA / PMN Number
    K170751
    Removal / Correction Number
    3011233554-03-18-2019-2C
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    WI, US
    Reporter Occupation
    OTHER HEALTH CARE PROFESSIONAL

    Narratives

    Additional Manufacturer Narrative · 1

    THE ANOMALY REPORTED FROM THIS SITE IMPACTS THE TREATMENT PLANNING AND DELIVERY SYSTEM (TPDS) SOFTWARE AND IDENTIFIED A SCENARIO WHERE A DISCREPANCY BETWEEN OPTIMIZATION AND PLANNING FORWARD DOSE CALCULATIONS CAN OCCUR. INVESTIGATION DETERMINED THAT IN SOME CASES THE TPDS SEQUENCER MAY PRODUCE A BEAM SEGMENT WITH A NEGATIVE BEAM WEIGHT. BEAM WEIGHTS WITH NEGATIVE VALUES ARE INTENDED TO BE DISCARDED BY THE SEQUENCER. IF THE SOFTWARE DOES NOT IDENTIFY THE NEGATIVE SEGMENTS AND DISCARD THEM, THEY ARE GIVEN TO THE DOSE ENGINE (REFERRED TO AS KMC IN WHAT FOLLOWS) FOR SEGMENT DOSE CALCULATION. IN KMC, THE LINAC SOURCE FINDS THE NEGATIVE BEAM WEIGHT AND RETURNS AN ERROR FROM THE SET SEGMENTS CALL. HOWEVER, WHEN THIS ISSUE OCCURS THE ERROR MESSAGE IS IGNORED BY THE DOSE CALCULATOR AND IT PROCEEDS WITH SEGMENT DOSE CALCULATION. THE LINAC SOURCE WILL NOT SET THE SEGMENT SHAPES FOR THE SEGMENTS THAT FOLLOW THE NEGATIVE BEAM WEIGHT SEGMENT; IT SIMPLY RETURNS THE ERROR AT THE NEGATIVE BEAM-ON-TIME SEGMENT WITHOUT FINISHING THE LOOP OVER SEGMENTS, RESULTING IN THE USE OF INCORRECT SEGMENT SHAPES AND HENCE IN A WRONG DOSE CALCULATION. AS A RESULT, WHEN THIS ISSUE OCCURS THERE IS LARGE DISCREPANCY BETWEEN THE OPTIMIZED DOSE AND THE CALCULATED DOSE.

    Description of Event or Problem · 1

    A USER OF VIEWRAY'S MRIDIAN SYSTEM S/N (B)(4) REPORTED AN OCCURRENCE OF A KNOWN DEFECT WHERE THE DOSE CALCULATION RESULT SHOWS A DIFFERENCE WHEN COMPARED TO THE RESULT CALCULATED IN THE PLANNING STEP WITH FORWARD CALCULATION. NO REPORT OF PATIENT INJURY. AN URGENT DEVICE CORRECTION NOTIFICATION ((B)(4)) HAD BEEN SENT TO THE SITE WHICH MADE THE USER AWARE OF THE SOFTWARE ANOMALY. THE SITE WAS CONDUCTING TREATMENTS ON THREE NON-HUMAN RESEARCH SUBJECTS. THE ANOMALY AROSE FOR EACH RESEARCH SUBJECT, DURING ON FRACTION EACH. TWO OF THESE WERE CAUGHT PRIOR TO TREATMENT AND ONE WAS NOT CAUGHT PRIOR TO TREATMENT. THIS ANOMALY ONLY ARISES DURING ADAPTIVE TREATMENT.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    333269 MRIDIAN LINAC RADIATION THERAPY IYE VIEWRAY, INC. 20000

    Patients

    Seq Age Sex Outcome Treatment
    1