Description of Event or Problem · 1
THE FOLLOWING DESCRIPTION IS A SYNOPSIS OF EVENTS LEADING UP TO AND INCLUDING THE BRACHYTHERAPY MISADMINISTRATION ON PT: PATIENT WAS DIAGNOSED WITH STAGE 2 SQUAMOUS CELL CARCINOMA OF THE VAGINA IN 2006. PATIENT CONSULTED WITH RADIATION ONCOLOGIST THE FOLLOWING MONTH WHERE A DECISION WAS MADE TO GIVE RADIATION THERAPY USING A COMBINATION OF EXTERNAL BEAM RADIATION AS WELL AS A BRACHYTHERAPY IMPLANT. DR DECIDED THAT HE WANTED TO TREAT THE INITIAL EXTERNAL BEAM RADIATION COURSE USING IMRT -INTENSITY MODULATED RADIATION THERAPY- TO MINIMIZE THE DOSES TO THE NORMAL STRUCTURES SURROUNDING THE TARGET AREAS. PATIENT HAD A PET/CT SCAN FOR INTENSITY MODULATED RADIATION THERAPY -IMRT- TREATMENT PLANNING IN 2007. IMRT TREATMENT PLAN COMPLETED AND SIGNED BY PHYSICIST AND PHYSICIAN. PRESCRIBED DOSES TO TARGET VOLUME, INTRAPELVIC NODES, AND VAGINA WERE 5590CGY, 4550CGY, AND 5070CGY RESPECTIVELY. DOSES TO POSTERIOR BLADDER WALL AND ANTERIOR RECTAL WALL WERE 5002CGY AND 5610CGY RESPECTIVELY. ION CHAMBER AND FILM DOSIMETRY QA PERFORMED THE NEXT DAY. QA RESULTS WERE WITHIN ACCEPTABLE LIMITS. PATIENT REC'D IMRT TREATMENT FOR 6 DAYS, 26 FRACTIONS TOTAL. BRACHYTHERAPY PREPLAN PERFORMED USING PROWESS BRACHYTHERAPY TREATMENT PLANNING SYSTEM, VERSION 4.3 -PROWESS, INC. PROCEDURE AUTHORIZATION FORM FAXED. FORM FAXED BACK ON THE SAME DAY. IRIDIUM-192 -IR-192- SEEDS AND NEEDLES ORDERED. FIFTEEN NEEDLES AND 11 RIBBONS WITH 8 SEEDS PER RIBBON WERE ORDERED. IR-192 SEEDS ARRIVED TO HOSP DEPARTMENT OF NUCLEAR MEDICINE TWO DAYS BEFORE EVENT DAY. THEY WERE THEN DELIVERED TO THE BRACHYTHERAPY LAB. SEEDS WERE LOGGED IN AND CALIBRATED BY PHYSICIST. APPLICATOR AND NEEDLES INSERTED IN HOSP OR BY DR THE FOLLOWING DAY. ONLY 9 NEEDLES WERE INSERTED. PATIENT BROUGHT FOR ORTHOGONAL FILMS AFTER OR PROCEDURE. AP AND RIGHT LATERAL FILMS TAKEN WITH DUMMY CESIUM-137 (CS-137) AND IR-192 SOURCES INSERTED INTO TANDEM AND NEEDLES RESPECTIVELY. PATIENT WAS THEN TRANSPORTED BACK TO THEIR ROOM. TREATMENT PLAN PERFORMED ON PROWESS TREATMENT PLANNING COMPUTER USING ORTHOGONAL FILMS WITH DUMMY SOURCES. IT WAS DECIDED TO USE 3, 10MG SOURCES FOR THE CS-137 TANDEM -DECAYED ACTIVITY = 6.87MG AS OF IMPLANT DATE . BASED ON THIS TREATMENT PLAN IT WAS DECIDED BY DR TO DELIVER 2500CGY TO THE 50CGY/HR LINE. THEREFORE, THE TOTAL TIME THE IMPLANT WAS TO STAY IN WAS 50 HOURS. CS-137 SOURCES AND IR-192 RIBBONS WERE PREPARED AND BROUGHT TO THE PT'S ROOM. SOURCES WERE LOADED INTO PT AT 2:30PM. ALL RADIATION SAFETY PROCEDURES WERE FOLLOWED. AS PER FACILITY'S POLICIES AND PROCEDURES, A POST-IMPLANT INDEPENDENT CALCULATION CHECK WAS PERFORMED. THIS WAS PERFORMED DURING LATE MORNING/EARLY AFTERNOON THE EVENT DAY. THE RESULT OF THIS CALCULATION SHOWED THAT THERE WAS MORE THAN A 10% DISCREPANCY BETWEEN THE NUMBER OF HOURS CALCULATED BY THIS DOUBLE CHECK CALCULATION AND THE POST-IMPLANT PLAN. THIS CALCULATION WAS DOUBLE CHECKED SEVERAL TIMES AND ALSO COMPARED TO PREVIOUS HAND CALCULATIONS PERFORMED ON OTHER PTS. BASED ON THE RESULTS OF THIS HAND CALCULATION, AN INVESTIGATION ENSUED AS TO WHY THERE WAS A DISCREPANCY BETWEEN THE HAND CALCULATION AND TREATMENT PLANNING COMPUTER CALCULATION. THIS INCLUDED REVIEWING THE POST-IMPLANT PLAN AS WELL AS THE DATA THAT WAS PUT INTO THE TREATMENT PLANNING COMPUTER . WHEN NOTHING WAS DISCOVERED, THE PHYSICIST PLACED A PHONE CALL TO PROWESS TECH SUPPORT. IT WAS DURING THIS PHONE CALL THAT A DATA ERROR WAS DISCOVERED. THE DOSE RATE CONSTANT FOR IR-192 ENTERED IN THE TREATMENT PLANNING COMPUTER WAS THAT FOR AIR KERMA -1.12- INSTEAD OF THE DOSE RATE CONSTANT FOR MG RADIUM EQUIVALENTS (8.25). WHEN THIS DOSE RATE CONSTANT WAS CHANGED, THE RESULTANT DOSE DISTRIBUTION OF THE POST-IMPLANT PLAN CHANGED. BASED ON THE ISODOSE DISTRIBUTION OF THE CORRECTED POST-IMPLANT PLAN, IT WAS DECIDED BY DR TO REMOVE THE IMPLANT. THE IMPLANT WAS REMOVED AT 5:30PM THAT DAY. IT HAD BEEN IN A TOTAL OF 27 HOURS. THE FACILITY PHYSICIST THEN REVIEWED THE INFO RELATED TO INTERSTITIAL BRACHYTHERAPY IMPLANTS IN THE PROWESS TREATMENT PLANNING MANUAL. THE RESULT OF THIS REVIEW REVEALED THAT THERE WAS NOTHING IN THE MANUAL INDICATING THAT THE DOSE RATE CONSTANT SHOULD BE CHANGED IF THE ACTIVITY OF THE SOURCES IS CHANGED. THE NEXT DAY, THE CORRECTED PLAN WAS REVIEWED BY THE FACILITY'S PHYSICIST, TREATING DR, AND FACILITY'S OWNER. FACILITY'S OWNER ASKED TO HAVE THE ORIGINAL TARGET VOLUMES FROM THE IMRT PLAN TRANSFERRED TO THE IMPLANT SIMULATION FILMS AS WELL AS THE ORIGINAL BRACHYTHERAPY TREATMENT VOLUME. HE THEN ASKED TO HAVE THE CORRECTED ISODOSE DISTRIBUTION TRANSFERRED TO THESE FILMS. THIS WAS PERFORMED BY THE FACILITY'S PHYSICIST AND DOSIMETRIST. BASED ON THE REVIEW OF THE CORRECTED PLAN AND THE INFO TRANSFERRED TO THE SIMULATION FILMS, IT WAS DETERMINED THAT THE 170CGY/HR LINE WAS COVERING THE ORIGINAL BRACHYTHERAPY TREATMENT VOLUME. THEREFORE, THIS VOLUME REC'D A TOTAL DOSE OF 170CGY/HR X 27 HRS = 4590CGY VERSUS THE PRESCRIBED DOSE OF 2500CGY. THEREFORE, THE ACTUAL DOSE DELIVERED EXCEEDED THE PRESCRIBED DOSE BY 83.6%. IT WAS AT THIS POINT THAT HE THOUGHT IT WOULD BE PRUDENT TO HAVE A SECOND PHYSICIST COME AND LOOK AT THE CASE.