Description of Event or Problem · 1
DEAR SIRS, SIEMENS MEDICAL SOLUTIONS IS CURRENTLY MARKETING A NEW CT SCANNER, CALLED THE DEFINITION. THIS IS A NEW TECHNOLOGY THAT USES 2 X-RAY TUBES, INSTEAD OF THE SINGLE TUBE CURRENTLY USED WITH MOST CT SCANNERS. IN THEIR MARKETING MATERIALS THEY CONSISTENTLY STATE THAT IT HAS THE FOLLOWING CLINICAL BENEFITS: "50% LOWER DOSE AT TYPICAL HEART RATES COMPARED WITH TODAY'S MOST DOSE-EFFICIENT, SINGLE SOURCE CT SCANNERS." THIS IS FEATURED PROMINENTLY IN THEIR MARKETING BROCHURE THAT I AM HAPPY TO EMAIL TO YOU AS A PDF BUT THERE IS NO WAY TO ATTACH IT HERE. THERE HAVE BEEN SEVERAL RECENT SCIENTIFIC PRESENTATIONS AT MEDICAL MEETINGS THAT HAVE FOUND THIS DOSE REDUCTION TO BE NOT TRUE. IN FACT, A RECENT COMPARISON OF THE EFFECTIVE RADIATION DOSE OF THE DEFINITION SCANNER, FROM A SERIES OF ACTUAL CLINICAL PTS AT THE FACILITY, FOUND THE EFFECTIVE DOSE OF THE DEFINITION SCANNER TO BE 25 TO 30% GREATER THAN SIEMENS SINGLE-X-RAY TUBE CT SCANNER. HERE IS A COPY OF THE ABSTRACT AS WELL AS A LINK TO AN ON-LINE SUMMARY OF THIS PRESENTATION THAT WAS GIVEN AT THE RADIOLOGICAL SOCIETY OF NORTH AMERICA ANNUAL MEETING IN CHICAGO IN NOVEMBER 2007: CODE: SSE09-06. SESSION: CARDIAC -CT- HOT TOPIC: RADIATION DOSE WITH CARDIOVASCULAR MULTI-DETECTOR ROW COMPUTED TOMOGRAPHY: COMPARISON BETWEEN SINGLE SOURCE AND DUAL SOURCE SYSTEMS IN PTS. DATE: MONDAY, NOVEMEBER 27, 2006, START TIME: 03:50PM, END TIME: 04:00PM, LOCATION: S503AB, DISCLOSURES S.H.-RESEARCH GRANT, SIEMENS AG P.S.-CONSULTANT, TAKEDA PHARMACEUTICAL COMPANY LIMITED, CHICAGO, IL, S.K.-NOTHING TO DISCLOSE. PURPOSE: ALTHOUGH USE OF A SECOND X-RAY TUBE W/ DUAL SOURCE CT INCREASED RADIATION EXPOSURE OTHER SYSTEM FEATURES WERE MODIFIED TO DECREASE EXPOSURE FOR CARDIOVASCULAR IMAGING: 1-ADD'L WEDGE FILTER, 2-MORE EFFICIENT TUBE CURRENT MODULATION, 3-INCREASED PITCH AT HIGHER HEART RATES -HR-. THIS WORK COMPARES RADIATION DOSE RECEIVED BY PTS IMAGED USING A SINGLE SOURCE SYSTEM W/DOSE RECIEVED BY A SECOND GROUP IMAGED USING A DUAL SOURCE SYSTEM. METHODS: 504 PTS WERE EVALUATED FOR CAD, CORONARY ANOMALIES, BYPASS GRAFTS, CARDIAC MASS, PULMONARY VEIN STENOSIS -PVS-, PERICARDIAL DISEASE, ARVD, CONGENITAL HEART DISEASE, THORACIC AORTIC AND THORACO-ABDOMINAL AORTIC DISEASE. THREE HUNDRED FORTY-FIVE PTS WERE IMAGED USING VARIOUS SPIRAL PROTOCOLS ON A 64-SLICE, SINGLE SOURCE CT SYSTEM -S64, SIEMENS-, 159 ADD'L PTS WERE IMAGED USING EQUIVALENT PROTOCOLS ON A 64-SLICE, DUAL SOURCE CT SYSTEM-DEFINITION, SIEMENS-. EFFECTIVE DOSE -E- WAS ESTIMATED FROM THE DOSE-LENGTH PRODUCT -DLP- {E=KXDLP WHERE K=0.017 MSV X MGY-1 X CM-1}. RESULTS: AVERAGE MAS/ROT, SCAN RANGE, AND HR WERE COMPARABLE FOR BOTH PT GROUPS. CAD, CORONARY ANOMALY, ARVD, AND CARDIAC MASS PTS WERE IMAGED W/330MS ROTATION, 0.6MM COLLIMATION, AND 250:410 MAS/ROT USING A SINGLE TUBE [N=124] AND TWO TUBES [N=50]; E AVERAGED 10.1/17.2 MSV WITH/WITHOUT TUBE CURRENT MODULATION USING A SINGLE SOURCE AND 12.6 MSV USING DUAL. IMAGING OF PVS W/330 MS, 1.2 MM SINGLE-/0.6 MM-DUAL-, 240:360 MAS/ROT RESULTED IN E=8.7/14.1 MSV USING SINGLE SOURCE [111] AND 11.5 MSV USING DUAL SOURCE [47]. FOR THESE INDICATIONS, E FOR THE ENTIRE GROUP WAS LOWER WITH DUAL SOURCE PRIMARILY B/C MODULATION COULD BE USED FOR EVERY PT DESPITE HR IRREGULARITIES. REMAINING PTS WERE IMAGED USING 1.2 MM COLLIMATION WITH MAS/ROT AND E AS FOLLOWS: BYPASS GRAFTS -240-320 MAS/ROT, SINGLE [11]: 12.1/20.1 MSV; DUAL [20]: 18.0 MSV-; PERICARDIAL, ARVD, CONGENITAL DISEASE -250-320 MAS/ROT, SINGLE [28]: 12.7/14.1 MSV, DUAL [12]: 12.1 MSV-, THORACIC AORTIC DISEASE -120-180 MAS/ROT, SINGLE [48]: 9.8/14.8 MSV-; DUAL [24]: 12 MSV-, AND THORACO-ABDOMINAL AORTIC DISEASE -140-200 MAS/ROT, SINGLE [23]: 15.9 MSV W/MODULATION, DUAL. THE KEY TO NOTE HERE IS THE RESULT THAT FOR CORONARY PTS "E AVERAGED 10.1/17.2 MSV WITH/WITHOUT TUBE CURRENT MODULATION USING A SINGLE SOURCE AND 12.6 MSV USING DUAL." HERE IS THE LINK FOR THE ON-LINE ARTICLE DISCUSSING THIS PRESENTATION THAT APPEARED IN THE ANTMINNIE.COM SITE: HTTP://WWW.AUNTMINNIE.COM/INDEX.ASP?SEC=SUP&SUB==CAR&PAG=DIS&ITEMID=74334. RADIATION IS A CARCINOGEN AND PT RADIATION EXPOSURE AND DOSE IS A VERY SERIOUS ISSUE. RADIOLOGISTS, AS WELL AS OTHER PHYSICIANS, MUST ADHERE TO THE ALARA -AS LOW AS REASONABLY ACHIEVABLE-PRINICPLE WHEN DETERMINING IMAGING EXAMS. WHEN A MAJOR MEDICAL EQUIPMENT VENDOR PLACES CLINICALLY UNSUBSTANTIATED CLAIMS SUCH AS THIS BEFORE US, IT CLEARLY HAS A GREAT INFLUENCE ON OUR PURCHASING DECISIONS. PRIOR TO MAKING A MULTIMILLION DOLLAR PURCHASE OF A PIECE OF CAPITAL EQUIPMENT SUCH AS A CT SCANNER, WE HAVE NO WAY OF INDEPENDENTLY VERIFYING THE VALIDITY OF THEIR 50% DOSE REDUCTION CLAIM. THEREFORE, MANY HOSPITALS AND IMAGING CENTERS ARE MAKING A DECISION TO PURCHASE THIS EQUIPMENT UNDER FALSE PRETENSES. I THINK THEIR 50% DOSE REDUCTION CLAIM WAS BASED ON CLAIMS BASED ON PHANTOMS; HOWEVER PHYSICIANS USE CT SCANNERS TO IMAGE REAL PTS. NOW THAT THERE HAS BEEN VALID RESEARCH INTO THE ACTUAL PT DOSE WITH THIS PARTICULAR SCANNER THEIR 50% CLAIM IS BOTH MISLEADING AND FRAUDULENT. I PERSONALLY FEEL THAT SIEMENS MEDICAL SOLUTIONS MUST BE MADE TO RETRACT THEIR CLAIMS OF A 50% DOSE REDUCTION, ISSUE A PUBLIC STATEMENT APOLOGIZING FOR THIS MISLEADING MARKETING CLAIM.