Description of Event or Problem · 0
A PATIENT WAS TO BE TREATED WITH CURATIVE INTENT USING VOLUMETRIC MODULATED ARC THERAPY (VMAT) TECHNIQUE TO THE PROSTATE, USING 6 MV PHOTONS, 5 DAYS A WEEK, WITH A PRESCRIBED DOSE OF 2.5 GY PER FRACTION TO A TOTAL DOSE OF 70 GY. ONE DAILY FRACTION (22ND OF THE 28 FRACTIONS) WAS MISTAKENLY DELIVERED WITH A SIGNIFICANT GEOGRAPHIC MISS OF THE PLANNING TARGET VOLUME (PTV). THE FACILITY'S PRACTICE FOR PROSTATE CANCER TREATMENTS INCLUDES INITIAL PATIENT AND COUCH POSITIONING USING A VACUUM-LOCK PATIENT IMMOBILIZATION DEVICE AND LASER ALIGNMENT TO MARKS ON THE PATIENT, AND THEN PERFORMING CONE BEAM CT (CBCT) IMAGING BEFORE DELIVERY OF EACH TREATMENT FRACTION. THE FACILITY DOES NOT PLACE FIDUCIAL MARKERS IN THE PROSTATE. DURING THE TREATMENT ON (B)(6) 2025, (FRACTION 22 OF 28), THE PATIENT WAS POSITIONED ON THE LINAC COUCH AND CONE BEAM COMPUTED TOMOGRAPHY (CBCT) WAS PERFORMED ON THE PATIENT. THE THERAPISTS PERFORMED A MATCH OF THE DAILY CBCT IMAGES WITH THE CT SIMULATION IMAGE SET. THEY NOTED THAT THE COUCH SHIFT WAS GREATER THAN 1.5 CENTIMETERS. (THE MACHINE WAS SET TO REQUEST A COUCH SHIFT LIMIT OVERRIDE FOR SHIFTS GREATER THAN THAT VALUE.) FACILITY PROCEDURES REQUIRED THE THERAPISTS TO OBTAIN PHYSICIAN APPROVAL OF THE IMAGE MATCH WHEN A COUCH SHIFT WOULD EXCEED THIS VALUE. AT THE FACILITY, ONLY THE PHYSICS TEAM (PHYSICISTS AND DOSIMETRISTS) HAVE THE PASSWORD TO ALLOW OVERRIDES OF COUCH SHIFT TOLERANCE LIMIT EXCEEDANCES. THE THERAPISTS CALLED A RADIATION ONCOLOGY ATTENDING PHYSICIAN AND A DOSIMETRIST TO THE CONSOLE. (A PHYSICIST WAS NOT AVAILABLE AT THAT MOMENT.) THE PHYSICIAN AGREED TO THE IMAGE MATCH. A THERAPIST ("THE DRIVER") APPLIED THE MATCH AND SENT IT TO THE LINAC. THE LINAC REQUESTED A COUCH TOLERANCE OVERRIDE DUE TO THE SHIFT BEING OUT OF TOLERANCE. THE DOSIMETRIST ASKED IF THE PHYSICIAN HAD AGREED TO THE IMAGE AND PROCEEDED TO SIGN OFF ON THE OVERRIDE. THE PATIENT WAS TREATED. THE ERROR WAS DISCOVERED BY ANOTHER RADIATION ONCOLOGIST WHEN HE WAS REVIEWING THE IMAGES OF THE DAY AND NOTICED A BIG DIFFERENCE IN THE IMAGE CO-REGISTRATION BETWEEN THE POSITIONS OF THE DAILY CBCT AND PLANNING CT IMAGE SETS. THE TOTAL VECTOR MAGNITUDE OF THE SHIFT WAS ABOUT 5.7 CM. FROM INTERVIEWING THE PERSONNEL, IT APPEARS THAT THE MATCH BETWEEN THE DAILY CBCT AND THE PLANNING CT IMAGE SETS WAS DONE CORRECTLY. HOWEVER, WHEN A THERAPIST WAS DRAGGING THE CURSOR ON THE TRANSVERSE IMAGE TOWARDS THE "APPLY" BUTTON, WHICH IS LOCATED AT THE BOTTOM RIGHT, THE THERAPIST MUST HAVE CLICKED ON THE IMAGE, KEPT THE MOUSE BUTTON PRESSED, AND BY MISTAKE DRAGGED THE IMAGE WHICH WAS ALREADY CORRECTLY MATCHED, CHANGING THE POSITION OF THE IMAGE AND SHIFTING IT LATERALLY AND VERTICALLY AS HE REACHED TO THE "APPLY" BUTTON TO APPLY THE MATCH (SHIFTS). THIS WAS A REPORTED MISADMINISTRATION, I KNOW OF ANOTHER REPORTED MISADMINISTRATION IN (B)(6) FOR THE SAME ISSUES WITH THE SOFTWARE. AND I KNOW THERE HAVE BEEN OVER 100 NEAR MISSES OVER THE PAST 2 YEARS AT MY FACILITY DUE TO THE SOFTWARE ISSUE. DIAGNOSIS FOR USE: CANCER THAT NEEDS RADIATION. DURATION: 6 YEARS. THE ISSUE IS THE "GUI" FOR THE CBCT FUSION HAS LEAD TO MISADMINISTRATION OF RADIATION DOSES TO PATIENTS. I DO NOT KNOW THE NAME FOR THE SOFTWARE THAT THE TRUEBEAM USES FOR OPERATIONS.