>> GOOD AFTERNOON AND WELCOME TO CLINICAL CENTER GRAND ROUNDS. TODAY'S A BUSY DAY IN TERMS EVER OPPORTUNITIES TO ATTEND LECTURES, TODAY'S RARE DISEASES DAY, FOR THIS VERY RARE DAY OF THE YEAR, FEBRUARY 29th. AND THIS AFTERNOON AFTER GRAND ROUNDS YOU'RE ALL WELCOME TO COME IN HERE FIRST 2 SPEAKERS AND MORE, IRA PASTAN AND HAL DIETZ WILL BE SPEAKING. TODAY'S TOPIC IS A HOT TOPIC FOR MANY REASONS. NOT THE LEAST OF WHICH, THIS IS A CENTER OF FOCUS FOR THE JOINT COMMISSION WHO ON REVIEWING HOSPITAL THIS IS YEAR IS GOING TO ASK EVERY HOSPITAL QUESTION ABOUT THE SUBJECT YOU'LL HEAR B. SO WE'RE VERY LUCKY THAT WE HEARD TO SPEAKERS FROM THE HEART AND LUNG AND BLOOD INSTITUTE FOR THE TOPIC OF RADIATION EXPOSE AND YOU ARE IMAGING AND DR. ANDREW WILL ADDRESS THE MAGNITUDE OF RADIATION AND DIAGNOSTIC IMAGES AND ASSOCIATED RISK AND DR. MARCUS, IS GOING TO PRESENT APPROACHING TO REDUCING RADIATION EXPOSURE IN CARDIOVASCULAR CT, IS THERE A PAIR, I WILL INTRODUCE BOTH SPEAKERS UNLESS A TAKE OVER THE PROGRAM. THE FIRST SPEAKER IS DR. ARAI, HE GRADUATED FROM CORNELL AND RECEIVED HIS MD FROM THE UNIVERSITY OF ILLINOIS AND COMPLETED RESIDENCY AND FELLOWSHIP IN CARDIOLOGY AT THE HEALTH SCIENCENESS UNIVERSITY AND THEN CAME TO HIS CURRENT LAB AS A VISIT RESEARCHER IN 1993 AND BECAME A SENIOR INVESTIGATOR IN 2004. DR. ARAI IS PRESIDENT OF THE SOCIETY OF CARDIOVASCULAR MAGNETIC RESONANCE AND MEMBER OF THE ARCI, AND HIS RESEARCHm FOCUSES ON ADVANCED CARDIOVASCULAR IMAGING INCLUDING CARDIAC MRI AND CT. OUR SECOND SPEAKER DR. CHEN IS A GRADUATE OF THE CALIFORNIA INSTITUTE OF TECHNOLOGY AND EARNED HIS MD AT THE UNIVERSITY OF WISCONSIN. AND HE COMPLETED A RESIDENCE NEUROECTODERMAL INTERNAL MEDICINE AND FELLOWSHIPS IN NUCLEAR MEDICINE AND CARDIOLOGY AT THE UNIVERSITY OF COLORADO MEDICAL SCHOOL. DR. CHEN HAS BEEN AT NIH SINCE 2006 WHEN WHEN HE BECAME A FELLOW AND CARDIOVASCULAR MAGNETIC RESONANCE IMAGING AND HE WAS NAMED A STAFF CLINICIAN IN 2008. AND NOW LET ME TURN THE PODIUM OVER TO DR. ARAI. >> THANK YOU JOHN FOR THAT KIND INTRODUCTION. I HAVE NO DISCLOSURES FOR THIS TALK. I THOUGHT I'D START WITH A COUPLE OF CLINICAL QUESTIONS FOR THE DOCTORS IN THE AUDIENCE. FOR PATIENTS YOU EVALUATE CLINICALLY, CAN YOU THINK OF A PATIENT THAT NEEDED 10 OR MORE DIAGNOSTIC TESTING, RADIATION, FLUOROSCOPY, AND YOU KNOW THERE ARE DIFFERENT LEVELS OF ANSWERS, IT IS NOT UNCOMMON TO SEE MANY TESTS DOING COMPLEX HOSPITALIZATIONS OR A SERIES OF HOSPITALIZATIONS TO USE THAT MANY TESTS OR EVEN RARE,--BY RARE--I KNOW MY ANSWER WOULD BE A OR B. NOW WHAT ABOUT--WHAT IS THE RISK OF A PATIENT DEVELOPING CANCER FROM A SINGLE CT SCAN. 1 IN A MILLION? ONE IN A HUNDRED THOUSAND? ONE IN 10,000? ONE IN A HELPED? I--1 IN A HUNDRED? >> MANY PEOPLE DOING THAT RESEARCH DON'T KNOW THE ANSWER BUT WE'LL GET TO IT. I GOT INTERESTED AS A PERSON WHO BE 1 OF THE BALANCING EXPERTS IN THIS AMERICAN HEART ASSOCIATION STATEMENT A COUPLE YEARS AGO, AND I'VE ALSO GOTTEN INTERESTED IN THIS TOPIC FROM THE OVERALL UTILIZATION OF IMAGING BECAUSE OF THE COST IMPLICATIONS, THIS IS CONSIDERED A VERY COSTLY METHODOLOGY WE ALL SEE REPORTS LIKE THIS IN 2009 AND CEDAR SINAI MEDICAL CENTER RECOGNIZED THEY HAD OVEREXPOSED PATIENTS GETTING DT BRAIN PROFUSION STUDIES, OVER 200 PATIENTS WERE INVOLVED AND BY THE PICTURE, THIS IS THE HEAD OF A LADY THAT WAS IN THAT GROUP, THERE'S HAIR LOSS FROM THE RADIATION EXPOSURE. AND ABOUT THAT SAME TIME IN CALIFORNIA, IN A SMALLER COMMUNITY HOSPITAL, SOMETHING WENT CRAZY IN A RADIOLOGY TECHNOLOGY AND THIS 23 MONTH OLD BOY ESSENTIALLY HAD CT SCANS OVER THE COURSE OF A 1 HOUR TIME PERIOD. >> --HER PAPERS FROM THIS DATE FROM THE 90S ARE CONSIDERED TOO DANGEROUS TO HANDLE. HER COOKBOOK IS TOO RADIOACTIVE AND KEPT IN LEAD LINED BOXES. SO THE FDA IS INTERESTED, THE JOINT COMMISSION IS INTEREST AS A THEY POINTED OUT SO THERE'S BEEN A SERIES OF ALERTS FROM 2009 LARGELY IMPLEMENTED TO MT. CEDAR SINAI AND OTHER EPISEDS HAVE HAPPENED AS WELL AND THE FDA DIRECTED STRONGLY OF CT SCANNERS TO DEVELOP HARDWARE AND SOFTWARE TO AVOID THIS KIND OF EXPOSURE. SO WHAT ARE THE ISSUES WITH THIS IN IF WE LOOK AT HOW MEDICAL RADIATION HAS CHANGED OVER TIME. IT'S GROWN ENORMOUSLY. IN 1980, MEDICAL EXPOSURE TO RADIATION, THE RED TRIANGLE THERE, REPRESENTED .5 MILLI CEFERTS, AND FAR AND AWAY THE GREAT MAJORITY OF RADIATION WAS FROM NATURAL SOURCES, AND SINCE 2006, MUST BE AROUNDING ERA BECAUSE THEY ANNOUNCED NATURAL RESOURCES AT 3 MILLI CEFERTS, AND THEY HAVEN'T CHANGED. BUT THE MEDICAL USE OF RADIATION INCREASED SO MUCH THAT IT NOW EQUALS THAT BACKGROUND RADIATION SOURCE AND AS YOU'LL SEE INDIVIDUAL TESTS CAN EQUAL OR EXCEED 1 YEAR EXPOSURE TO RADIATION. SO WHAT ARE THE NATURAL SOURCES? THESE ARE THE 1S WE CAN'T DO A LOT ABOUT. THINGS LIKE COSMIC RAYS FROM THE ATMOSPHERE. OUR SUPERNOVA, OUR SUN. THERE'S ALSO RADIATION THAT COMING UP FROM THE GROUND. EVERYONE'S HEARD ABOUT RADON. RADON IS THE NUMBER 2 RISK OF CAUSING LUNG CANCER AND CONSIDERED ATTRIBUTABLE 21,000 DEATHS PER YEAR WHICH IS ACTUALLY PEOPLE HAVE HEARD ABOUT THIS IN THE LAY PRESS BUT IT'S SMALL COMPARED TO THE RISK OF SMOKING AND PUT UP THE MAPS FOR VIRGINIA, AND MARYLAND, AND MANY OF THE COUNTIES IN OUR AREA ARE IN THE RED ZONES OF HIRE RADON EXPOSURES SO IF YOU HAVEN'T DONE IT, IT'S WORTH HAVING YOUR HOUSE CHECKED, THERE ARE SIMPLE DEVICES TO SEE IF HAVE YOU RADIATION--YOU HAVE RADIATION ISSUES AND YOU CAN CHANGE THE VENTALATION IN THE HOUSE TO MINIMIZE THESE EXPOSURE. IT'S WORTH THINKING JUST ABOUT THE UTILIZATION OF IMAGES AND THE IMAGING HAS EXPLODED. THIS IS A PLOT OF THE NUMBER OF CT OR MRI PROCEDURES PER THOUSAND MEDICARE PATIENTS PER YEAR, THE REMEMBER THE DENOMINATOR IN THIS GRAPH IS A THOUSAND MEDICARE PATIENTS AND IF YOU LOOK AT THE Y AXIS, WE'RE TALKING HUNDREDS. THE 547 CD SCANS PER MEDICARE PATIENT PER YEAR, THAT'S INCREDIBLE. MRI'S ALSO HEAVILY USED. 173 PROCEDURES FOR THOUSAND PATIENTS PER YEAR. WELL, NOT SURPRISINGLY, DEATH IS A MAJOR DRIVING FACTOR IN THE COST OF MEDICINE. AND IF WE LOOK AT THE TYPES OF IMAGING THAT REALLY DRIVE UP COSTS, THE LEADER IS IMAGING OF THE C& S OR SPINE. NUMBER 2 UP THERE IS THE CARDIAC OR CHEST IMAGING, BUT THERE'S QUITE A WIDE RANGE OF IMAGING THAT LEADS TO VERY HIGH COSTS OF MEDICINE. AND IN FACT, THE RATE OF GROWTH, EVERYONE WHO LOOKED AT THEIR RETIREMENT FUNDS OR LOOKED AT THEIR BANK INTEREST RATES AND SEES 1% INTEREST IN YOUR SAVINGS ACCOUNT, THE COST OF MEDICINE IS GOING UP FEROCIOUSLY. THESE ARE FACTORS THAT THE CLINICAL CENTER IS REALLY STRUGGLING WITH AS A RESULT. BUT IF YOU LOOK ACROSS THE BOARD, THE RATE OF—rGROWTH OF IMAGING PARTICULARLY, ADVANCED IMAGING LIKE CT AND MRI HAD ANNUAL GROWTH RATE IN 2005 OF 25%. THAT IS TRULY PHENOMENAL AND UNFORTUNATELY WHAT THAT IS DOING IS IT'S REALLY BANKRUPTING OUR ABILITY TO PAY FOR OTHER THINGS IN MEDICINE AND AS WELL AS BALANCE THE BUDGET BETWEEN MEDICAL COSTS AND OTHER ASPECTS OF THE FEDERAL GOVERNMENT ANDA AS OF 2005, IMAGING REPRESENTED ABOUT 14% OF TOTAL MEDICAL SPENDING. NOT SURPRISINGLY REGULATORS ARE TRYING TO FIND WAYS TO SLOW THIS DOWN. AND 1 OF THE THINGS THEY LOOK AT ARE VARIOUS STATISTICS THAT TRY TO HAPPENED WHY THIS HAPPENS AND THIS IS 1 OF THE MORE INTERESTING SLIDES I CAME ACROSS WHILE LOOKING 3 THROUGH THESE ECONOMICS. THESE 2 CORRELATIONS, ARE THE CORRELATION BETWEEN THE NUMBER OF--OR THE CHANGE IN THE NUMBER OF TOTAL CT SCANNERS, ON THE X AXIS FOR THE GRAPH AT LEFT, VERSES THE CHANGE IN TOTAL CT CLAIMS AND THERE'S AN R VALUE OF ABOUT .95 BETWEEN INCREASES IN SCANNERS AND INCREASES IN MEDICARE CHARGES THAT APPLIES TO MRI AS WELL. PERHAPS DIFFERENT SIZES, LARGELY THEY TRY TO KEEP THEM PROPORTIONAL. BUT THE COSTS ARE INCREDIBLE. SO WHEN YOU LOOK AT IT, PUTTING IN 1 NEW MRI SCANNER, IT ADDS MEDICARE COSTS IN THAT AREA AT 550 THIS HAPPENED DOLLARS A YEAR,--$550,000 A YEAR, AND INCREASED MEDICARE REIMBURSE AMS ARE FILLING BY $565,000 IF YOU LOOK AT THE COST OF MEDICARE SPENDING FROM 2000-2005, 13.6 TO 13-POINT--6.6 TO 13.7 BILLION DOLLAR AND IT AREYALATES TO THE TOPIC--RELATES TO THE TOPIC OF RADIATION I'LL GO TO NEXT. BEFORE WE GO TO RADIATION, IT'S WORTH THINKING ABOUT WHY DO PHYSICIANS ORDER TOO MANY IMAGING TESTS? THESE ARE A LIST OF HYPOTHESIS THAT WERE PUBLISHED IN AN OPINION PIECE IN THE NEW ENGLAND JOURNAL OF MEDICINE IN 2010. 1 FACTOR IS PATIENTS REQUESTING IMAGING BASED ON THE ADVERTISING THEY SEE ON TV. A LOT OF PEOPLE THINK THIS IS FINANCIAL REWARDS, IMAGE SUGGEST A WELL REIMBURSED SPECIALTY, SO, PHYSICIANS IN THOSE SPECIALTIES LIKE TO DO THESE PROCEDURES. REFERRAL IS THOUGHT TO BE A FACTOR, SOMEONE OWNS A SCANNER, THEY SEND PATIENTS TO THEIR OWN SCANNER AND THEY MAKE A LOT OF MONEY OFF THAT. BUT THERE ARE OTHER FACTORS AND THEY'RE IMPORTANT FACTORS, IT'S THOUGHT THAT 28% OF DIAGNOSTIC IMAGING IS ATTRIBUTABLE TO CONCERNS ABOUT MEDICAL MALPRACTICE, PARTICULARLY THE FAILURE TO DIAGNOSE CONDITIONS. IN ADDITION, PHYSICIANS THAT INTERPRET THESE SCANS MAY RECOMMEND ADDITIONAL TESTING TO PROTECT THEMSELVES IN CASES OF DIAGNOSTIC UNCERTAINTY. VERY INTERESTING ASPECT THOUGH IS THE WAY WE TRAIN OUR PHYSICIANS. SO IF YOU LOOK AT WHERE-b6 RESIDENTS AND FELLAS GET TRAINED OR TYPICALLY A LARGE PERCENTAGE OF MAJOR ACADEMIC CENTERS WHERE YOU HAVE FACULTY WHO HAVE OTHER DEMANDS ON THEIR TIME AND DECIDES THE MEDICAL CARE, THE RESEARCH CAREERS THAT THEY'RE TRYING TO PROMOTE. SO AS A RESULT, THE HIGH INTENSITY, HIGH THROUGH PUT MEDICAL SYSTEMS IN THE PART-TIME NATURE OF THE PEOPLE THAT TRAINED PHYSICIANS, LEADS TO AN INTENSITY OF ORDERING MANY TESTS THAT GET THE ANSWER THROUGH WHATEVER MEANS POSSIBLE. THERE'S ALSO WHEN WE SEE COMPLICATED PATIENTS AT PLACES LIKE THE NIH OR THE REFERRAL CENTER, A DESIRE TO LEAVE NO STONE UNTURNED TO GET AN ANSWER IN AN INDIVIDUAL PATIENT. THE BAD NEWS IS PHYSICIANS LEARN THIS HABIT OF ORDERING MANY TESTS AND EVEN WHEN THEY GO TO A LOWER SETTING THEY CONTINUE TO ORDER TOO MANY TESTS. SO LET'S TRANSLATE THIS NOW TO RADIATION EXPOSURE AND DOZE. THERE ARE A LOT OF DIFFERENT PARAMETERS THAT YOU'LL SEE IN RADIATION EXPOSURE TTURNS OUT EXPOSURE IS EASY FOR THE MACHINE TO MEASURE, WE KNOW HOW MANY PHOTONS OR POWER LEVELS ARE PUT INTO THE SCANNER AND SENT INTO THE PATIENT. IT'S MUCH HARDER THOUGH TO KNOW HOW MUCH ACTUALLY GOT ABSORBED BY THE PATIENT AND THEREFORE POTENTIALLY DAMAGED THE PATIENT. AND SO, THE 2 FACTORS I'D LIKE TO HIGHLIGHT. DOSE LENGTH PROD SUCKET A GOOD WAY OF LOOKING AT EXPOSURE,OT THIRD LINE HERE, THE X-RAY EXPOSURE, TIMES THE LENGTH THE BODY EXPOSED FOR EXAMPLE IN A CT SCAN. IS A GOOD WAY OF KNOWING HOW MUCH RADIATION WENT INTO THE PATIENT, IT TURNS OUT WE DON'T HAVE GOOD WAYS OF MEASURING THE ABSORBED RADIATION DOSE. SO WE DON'T TALK ABOUT THAT VERY MUCH, ALTHOUGH OLDER STUDIES FREQUENTLY HAVE THESE MILLI GRADE UNITS IN THEM IN WHICH CASE THEY'RE TRYING TO ESTIMATE OR GUESS WHAT THOSE RADIATION DOSES WERE. MORE COMMONLY YOU SEE PEOPLE TALKING ABOUT THE EFFECTIVE DOSE OR E IN UNITS AND MILLI CEIVERS, AND THIS IS MEANT TO AFFECT THE RISK THE BIOLOGICAL AFFECTS OF IONIZING RADIATION AND IT REPRESENTS THE AMOUNT OF WHOLE BODY RADIATION THAT VIEWED THE WHOLE BIOLOGICAL RISK OF, 85ULENT AND THAT OF A PORTION TO THE BODY. I. E. EXAMPLE MEDICAL IMAGING. AGAIN IT'S NOT DIRECTLY MEASURED, IT'S NOT QUANTIFIED PRECISELY, IT USES MODELS, SO IT REALLY IS NOT INDIVIDUALLY APPLICABLE TO PATIENTS. IT'S 1 OF OUR BETTER OVERALL ESTIMATES OF HOW PEOPLE ARE GETTING EXPOSED. NOW TO CALCULATE DOSE, EFFECTIVE DOSES, WE TAKE THE DOSE LENGTH PRODUCT, THE PATIENT'S BEEN EXPOSED TO AND MULTIPLY BY A K FACTOR, WELL IT TURNS OUT THAT K-FACTORS ARE CHANGE NOTHING 2004, THE KFACTOR THAT WE USED FOR THIS CARDIAC IMAGE SUGGEST 0.014. AND 4 YEARS LATER IT'S INCREASED AND ALMOST DOUBLED SO IN 1 CHANGE WITH GUIDELINES RADIATION EXPOSURES DOUBLED ALTHOUGH THEY KNOW YOU DIDN'T, BUT THE EFFECTIVE OR THE IMPLICATIONS OF EFFECTIVE EXPOSURE WERE THOUGHT TO INCREASE. SO HOW MUCH RADIATION DO VARIOUS TESTS EXPOSE PATIENTS TO. WELL, I'VE PUT SEVERAL HERE, CT OF THE CHEST, ABNORMALITIES DOMIN AND PELVIS IN GENERAL IN THE 8 TO 7 MILLI CEIVER RANGE, THE STUDY FROM THIS TIME, YOU'LL SEE WHERE WE'VE GONE SINCE THEN IN THE 16 MILLI CEIVE EXPOSURE TO RADIATION RANGE, DIAGNOSTIC CORONARY ANGIOGRAM, ABOUT 7 MILLI CEIVE EXPOSURE TO RADIATIONS, BUT THERE'S A TREMENDOUS AMOUNT OF VARIATION FROM CENTER TO CENTER, USING THE SAME CT SCANNERS, SO FOR EXAMPLE, THIS IS FROM A MULTICENTER STT STUDY OF CORONARY CTA IF YOU LOOK AT THE FIRST SET OF FIGURES HERE, THAT SOME CENTERS USE ABOUT 1 QUARTER THE RADIATION OF OTHER CENTERS AROUND THE WORLD USING EXACTLY THE SAME SCANNER, AND THAT'S TRUE NOT JUST FOR GE PHILLIPS, IT'S ACROSS THE BOARD, TREMENDOUS VARIABILITY IN THE USEDDERS EXPOSURE OF PATIENTS USING THE SAME EQUIPMENT. A LOT OF PEOPLE DON'T THINK TOO MUCH ABOUT RADIATION WHEN THEY ORDER A STRESS TEST. 1 OF THE MOST COMMONLY ORDERED TEST IS A SPEC TEST F. YOU USE VALIUM THAT'S EQUIVALENT TO 40 MILLI CEVERTS, STILL. BUT IF WE LOOK AT THE BIGGER PICTURE, WHERE DOES ALL THE EXPOSURE COME FROM. IF YOU LOOK AT THE COUNTRY OVERALL? FROM THE STANDPOINT OF SCANS, X-RAYS, TYPE STUDIES, CARDIAC IN RED IS A SMALL PARTICIPANT AT THIS TIME. THE BIG SOURCE COMES FROM THE ABDOMEN AND PELVIS TYPE SCANS AND OTHER PERIOD PARTS. AND ON THE OTHER HAND WHEN WE LOOK AT THE NUCLEAR EXPOSURES AND CARDIAC IS CLEARLY THE BAD BOY WITH THE GREAT MAJORITY OF STUDIES EXPLANNABLE BY CARDIAC STRESS TEST. SO WHAT ARE THE RISKS ASSOCIATE WIDE THIS KIND OF RADIATION EXPOSURE. BESTS DATA WE HAVE COMES FROM HIRE O--HIROSHIMA. THERE HAVE BEEN FOLLOW STUDIES TO FIGURE OUT HOW MUCH ACCESS CAME FROM THE RADIATION EXPOSURE FROM HIROSHIMA. YOU HAVE TO THINK THERE CAN BE TREMENDOUS ERROR BARS AT THIS ESTIMATE. HOW CAN YOU KNOW HOW MUCH SOMEONE WAS EXPOSED OR HOW MUCH THEY SAW. BUT THIS TORNS OUT TO BE SOME OF OUR BEST DATA AND IF WE LOOK AT RADIATION DOSE VERSES EXCESS RELATIVE RISK OF SOLID CANCER AND THE BLACK LINE OR THE LEUKEMIA AND THE RED LINE, WE CAN SEE THAT THERE'S AN INCREASE IN RISK, AS THE DOSE GOES UP. THERE'S A LOW DOSE RANGE THAT'S APPLICABLE TO MEDICAL IMAGING AND SO, WHILE IT'S CLEAR HIROSHIMA, OUR PATIENTS HAD LOTS OF EXPOSURE WHEN YOU GET DOWN TO THE LOW DOSE RANGE FOR MEDICAL IMAGING,s;Rmh THERE'S MORE CONTROVERSY BECAUSE WE'RE EXTRAPOLATING NOW IN THE ERROR BAR O SINGLE THE REAL ESTIMATES START TO CROSS THE 0 LINE. PEOPLE HAVEN'T FIGURED OUT HOW BEST TO DEAL WITH IT. IF YOU READ THE PAPERS YOU'LL SEE THERE'S CONTROVERSY. THERE'S SOME RADIATION THERE AND PROPOSED THRESHOLD MODELS BUT THE RADIATION SAFETY COMMUNITY HAS GENERALLY ACCEPTED WHAT'S CALLED THE LINEAR NO THRESHOLD MODEL IN OTHER WORDS AT THE LOWEST DOSE THERE OF RADIATION EXPOSURE THERE MAY BE SOME RISK, AND MOST OF THOSE EXTRAPOLATION RISKS ARE BASED ON THIS KIND OF DATA. SO WHAT--HOW MUCH CANCER CAN WE ATTRIBUTE TO RADIATION FROM MEDICAL IMAGING? IF EACH DOT REPRESENTS A PERSON HERE, SO THEY'RE 10 BY 10 MATRIX. YELLOW ARE THE PEOPLE THAT ARE GOING TO AND IF WE LOOK AT HUNDRED MILLI CEVERT RANGE WE WOULD INCORPORATE A HUNDRED PATIENTS INTO THIS RANGE AND YOU WOULD SAY, GHEE IF THERE'S THAT MUCH INCREASE IN RADIATION RISK, IT SHOULD BE EASY TO PICK UP ON BUT IT TURNS OUT THIS IS A VERY DIFFICULT THING TO SHOW IN MEDICAL STUDIES AND IT'S--IF YOU LOOK AT THE NUMBERS HERE, IF YOU LOOK AT BACKGROUND INCIDENCE OF CANCER IS 43%, INCREASE TO 44%, WE CAN DO A SIMPLE SAMPLE SIZE CALCULATION. THIS WAS SUPPOSED TO BE A POWER OF .9, 51,000. BUT THE SAMPLE SIZE FOR AN ALPHA .5 AND A POWER OF PASSPORT 9 REQUIRES THE SIDE--.9 REQUIRES THE STUDY OF PANE--59,000 PEOPLE. 1% NOT A BIG DEAL? WELL 1% OF 3 MILLION UNITED U.S. CITIZEN IS A BIG DEAL. AND YOU THINK IT WOULD BE EASY TO PICK UP A MILLION PATIENT RISKS BUT IT'S NOT EASY. SO IT'S DIFFICULT, THERE ARE OTHER BIOLOGICAL FACTORS THAT MAKE IT DIFFICULT TO ESTIMATE THESE THINGS. 1 OF THEM, MALIGNANCIES THAT SHOW UP FROM RADIATION TEND TO LIKE LIKE THE MALIGNANCIES THAT SHOW UP FOR GENERAL REGIONS. SO IF WE GET TO THE CANCERS RISK, MY FIRST QUESTION TO YOU IS WHAT ARE THE RISKS. AND IT TURNS OUT TO BE AN AGE DEPENDENT FACTOR. BUT ESTIMATES ARE AS HIGH AS 143 WOMEN INTO 20 YEAR-OLD RANGE. THEY GET A CT SCAN OF THE CHEST. 1 CTSCAN OF THE HEART WITH OLDER RADIATION LEVELS WOULD DEVELOP A FATAL CANCER. THAT'S INCREDIBLE, NOWHERE NEAR--SO WE NEED TO DO THINGS TO REDUCE THE RISK. FORTUNATELY, RISKS GO DOWN A LOT, IN OLDER PATIENTS AND THERE'S ALSO A FACTOR THAT IT TAKES ABOUT 10 YEARS TO CATCH UP WITH THESE RISKS SO IT'S HARD TO PICK UP ON. BUT AS PEOPLE GOT MORE ATTENTION TO THIS, PEOPLE REALIZED THAT IT'S NOT JUST A SINGLE STUDY THAT'S THE PROBLEM. SO ANOTHER 1 OF ANDROGEN ANDROGEN--ANDREWS STUDIES LOOKED AT COLUMBIA UNIVERSITY PATIENTS THAT HAD A STRESS TEST ORDERS. A STUDY OF ABOUT 1100 PATIENTS AND THEY LOOKED BACK THROUGH JUST THE COLUMBIA RECORDS AND RECORDS THEY HAD AVAILABLE TO THEM OVER THE PRECEDING 10 YEAR PERIOD. THE MEDIAN NUMBER OF PROCEDURES THAT PATIENT HAD THAT INVOLVED IONIZING RADIATION WAS 15, BUT 344 OUT OF THESE 1100 PATIENTS OR 31% HAD A CUMULATIVE DOSE EXPOSURE OVER A HUNDRED MILLI CEVERTS, THAT'S THE RANGE WHERE HIROSHIMA HAS UNCERTAINTY WHERE CANCER IS INVOLVED. SO IT'S MULTIPLE PROCEDURES THAT LEADS UP TO TROUBLE. JUST SO WE DON'T CARE EVERYONE, TOO MUCH ABOUT RADIATION, IT'S WORTH PUTTING SOME THINGS INTO PERSPECTIVE, LIKE IF YOU FLY TO TOKYO, YOU GET ABOUT .07 MILLI CEVERTS, THAT'S THE EQUIVALENT OF 7 DAYS EXPOSE TO BACKGROUND RADIATION. 3-MILE ISLAND EXPOSURES EQUIVALENT TO ABOUT .01 MILLI CEVERT EFFECTIVE DOSES, EACH PEOPLE AT THE PLANT WOULD YOU NOTARY GOT A MILLI CEVERT. SO THIS IS THE RANGE THAT WE'RE WORRIED ABOUT. IN CHERNOBYL THOUGH, MANY DIED, BUT THE EXPOSURES WERE OVER A HUNDRED MILLI CEVERTS. AND IF WE LOOK AT RISK FROM DAILY LIFE, A RISK OF DYING OF A FATAL MALIGNANCY FROM A CALFIUM SCORE WITH 1 MC, A CT SCAN, .5 IN A THOUSAND PEOPLE OVERALL, HAS THE SMOKING FOR 10 PEOPLE, OR EXPOSURE FROM RADON, HIGH EXPOSURE, 21 IN A THOUSAND PEOPLE. SO SINGLE TESTS ARE SMALL RELATIVE TO THINGS THAT WE TAKE AS COMMON RISKS IN DAILY LIFE. AND FINALLY, WE NEED TO PUT IN PERSPECTIVE THAT THERE'S REALLY--WE HAVE TO TAKE EVERYTHING IN MEDICINE IN A RISK BENEFIT ANALYSIS, SO THERE ARE PATIENTS THAT HAVE LIFE THREATENING CONDITIONS THAT GET DIAGNOSED BY CT SCAN AND CAN CHANGE THEIR MANAGEMENT. AND SO, WE DON'T WANT PEOPLE TO GET SO SCARED THAT THEY WON'T SIGN UP FOR THE DIAGNOSTIC TESTS THAT;CxÖK ARE NECESSARY TO MANAGE THEM. I THINK FOR THE SAKE OF TIME I'LL SKIP IT 1. IT IS ALSO IMPORTANT TO RECOGNIZE THAT YOU MIGHT THINK, WELL, LET'S JUST LOOK AT THE NUMBER OF TESTS THAT REALLY DID CHANGE MANAGEMENT. THAT'S PROBABLY NOT A GOOD WAY OF AN ANALYZING THE PROBLEM BECAUSE SOMETIMES WHEN THERE'S A NEGATIVE TEST, IT HELPS POINT US IN A DIFFERENT DIRECTION, SO THAT'S A CERTAIN NUMBER OF NEGAATIVE TESTS. IF WE BRING THIS TO A CONCLUSION, THOUGH, I THINK IT'S PRETTY CLEAR, MEDICAL IMAGING IS THE LARGEST CONTROLLABLE SOURCE OF RADIATION PATIENT EXPOSURE IN THE U.S. THE WAY WE FIX THIS PROBLEM THROUGH PHYSICIAN EDUCATION, SIMPLE THINGS WE CAN DO IS AVOID TESTS THAT HAVE BEEN DONE IN OTHER HOSPITALS AND DISCUSS THE RISKS WITH THE PATIENT. THERE ARE CERTAIN TYPES OF TESTS THAT ARE COMMONLY ORDERED THAT JUST SHOULD NOT HAPPEN, ROUTINE SURVEYS VAILANCE WITH NUCLEAR STRESS TESTS OR CARDIAC CTs ARE NOT RECOMMENDED. WE SHOULD CONSIDER TESTS THAT DO NOT USE IOINIZING RADIATION. I'M A BIG PROPONENT OF CARDIAC MRI AND MAYBE MRI COULD BE USES FOR A WIDER RANGE OF OTHER APPLICATIONS. WE NEED TO DEVELOP METHODS TO TRACKING INDIVIDUALS, LIFETIME RADIATION, THIS HAS DIFFICULT FACTORS ASSOCIATED WITH IT. THEY'RE GONNA BE BENCHMARKS FOR NATIONAL STANDARDS AND THE SECOND HALF OF THIS GRAND ROUNDS DR. CHEN WILL DESCRIBE HOW ADVANCES IN TECHNOLOGY AND EDUCATION CAN MARKEDLY REDUCE RADIATION EXPOSURE. THANK YOU VERY. --THANK YOU VERY MUCH. D. [ APPLAUSE ] >> DISCUSSING APPROACHES TO REDUCING RADIATION DISCUSSION IS CARDIOVASCULAR CT. NO DISCLOSURES. HERE'SEUR LEARNING OBJECTIVES. IDENTIFY BARRIERS I'LL OPEN WITH 2 CT SCANS, 1 ON THE LEFT AND 1 ON THEœ THESE ARE BOTH TIKI SCANS OF THE AORT. AND HOW MUCH RAIDIATION DO YOU THINK WAS REQUIRED FOR THESE 2 DIFFERENT STUDIES. AND THE IMAGE QUALITY IS PRETTY COMPARABLE BETWEEN THE 2? THIS WAS SENT TO ME TO REVIEW AS A SECOND OPINION. WHEN I LOOK AT THE SYMMETRY PAGE, THAT EXAM WAS AT 65 MILLI CEVERTS STUDY, IT WAS A HIGH RADIATION DOSE. THAT SEEMED WEAK, AND PERFORMED THE OTHER IMAGE WHICH WAS LESS THAN 1 MILLI CEVERT. SAME AMOUNT OF COVERAGE. THIS IS PATIENTS BUT THIS SHOWS YOU WHAT--WHAT CAN BE DONE TO REDUCE RADIATION DOSE THAT CAN YOU GET DIAGNOSTIC IMAGES OF THE SAME PART OF IT IS SUBSTANTIALLY REDUCED DOSE. BETWEEN THE 2 STUDIES THERE'S 80 FOLD DIFFERENCE. THIS IS THE SAME AS WHAT DR. ARAI SHOWED HOW THERE'S DIFFERENCE BETWEEN INSTITUTION PLATFORMS. JUST TO SHOW MORE IMAGES OF THAT STUDY, PATIENT HAD A THE PATIENT HAD THE STENOSIS AND THE LED, THIS IN THE RIGHT CORNORARY ART RIGHT, AND THESE FINDINGS WHICH WERE CONFIRMED. SO AS A DIAGNOSTIC CLUSTER OF 1 MILLI CEVERT. IT'S INTERESTING TO GO THROUGH ALL THE PROCEDURES AND WE WON'T GO THROUGH THAT TODAY, BUT THERE ARE 2 HERE AT THE CLINICAL CENTER HERE. THERE'S PHILLIPS ICT AND HOWEVER THERE IS ALSO A FLASH COME NOTHING THE NEAR FUTURE. TED REAL IMPORTANCE IS THAT IT'S NOT ABOUT THE SCANNERS THAT REDUCE DOSE. TEAM EFFORT BETWEEN THE REFERRING PHYSICIAN FOR THE TEST, THE SUPERVISING RADIOLOGIST OR CARDIOLOGIST THAT IS SUPERVISING THE PROCEDURE AND THE NURSE PRACTITIONER THAT HELPED THE PROCEDURE, IT'S A TECHNOLOGYST WHO'S ACQUIRING THE PICTURES AND THERE'S ALSO INTERACTION WITH THE MEDICAL PHYSICIST, THE APPLICATION SPECIALIST AND DEVELOPMENT ENGINEERS TO BUILD AND DEVELOP PROTOCOLS WHICH CAN REDUCE DOSE. AND THE OVERALL GOAL IS TO PERFORM THE RIGHT SCANOT RIGHT PATIENT WITH THE CORRECT DOSE. SO 1 METHOD TO REDUCE DOSE IS TO HAVE A PURPOSE CRITERIA. SINCE 2006, AMERICAN COLLEGE OF CARDIOLOGY, AMERICAN HEART ASSOCIATION PLUS NUMEROUS OTHER SOCIETIES GOT AND MADE CRITERIA FOR CARDIOVASCULAR CT. THESE WERE DONE IN 2006 AND THEY RAPIDLY OP DATED THEM IN 2010 DUE TO THE EVOLVING TECHNOLOGY AND EXPANDING CLINICAL INDICATIONS AND ESSENTIALLY THERE WAS A PANEL OF EXPERTS WHO WENT THROUGH SCENARIOS AND RENDERED THEIR OPINION IN TERMS OF WHAT WOULD BE AN APPROPRIATE USE OF THE TESTS FOR CLINICAL SITUATIONS. HERE'S JUST 1 EXAMPLE, THIS IS JUST 2 OF THE 6 DIFFERENT MEDICATIONS, THIS IS A PRETTY COMMON SCENARIO. SO IT'S NONACUTE SYMPTOMS, POSSIBLY REPRESENTING AN ASCHEMIC EQUIVALENT. THIS WAS EVALUATION OF CHEST PAIN. THE THIS IS BROKEN UP, LOW TO HIGH AND FIRST, CRITERIA WILL HAVE TROUBLE WITH EKG AND ARE THEY ABLE TO EXERCISE. YES, THE PRETEST POSSIBLABILITY HAVING CORONARY DISEASE IS LOW, AND IT'S YOU ARE UNCERTAIN IF PERFORMING CARDIAC CT WILL BE APPROPRIATE. OF HAVING CORONARY DISEASE AND IT'S APPROPRIATE TEST TO HAVE CT, IF IT'S A HIGH PRETEST PROBABILITY, YOU SHOULD NOT DELAY MEDICAL CARE BY DOING A BASIC TEST, MAYBE YOU SHOULD PERFORM THE BASAL TEST WHERE YOU DO THERAPEUTIC OXYGEN AT THE SAME TIME. SO THERE'S 3 BASIC MECHANISMS OF REDUCING RADIATION DOSE OF DECREASED EXPOSURE TIME, THE DECREASED PHOTONS YOU DELIVER TO FORM THE IMAGE AND THE THIRD METHOD IS TO SUFFICIENTLY USE THE INFORMATION YOU ALREADY HAVE. SO FIRST 1 IS DECREASING EXPOSURE TIME. SO THE TRADITIONAL CARDIOVASCULAR CT IS A 15 TO 25 MILLI CEVERTS STUDY, AND IT'S RETROSPECTIVE GAINING, THE HEART IS ALWAYS MOVING, I CAN'T REALLY USE THIS FOR THE HEART AND IMAGES WERE REQUIRED SYNCHRONIZED TO EKG, AND WHILE THE EKG WAS GOING, THE HEART WOULD BE SCANNED CONTINUOUSLY THROUGHOUT THE CARDIAC CYCLE. THIS WOULD LEAD TO PRETTY SIGNIFICANT RADIATION DOSES. WHEN YOU LOOK AT IT, WHEN YOU'RE ABLE TO GET IS YOU ACQUIRE IMAGES THROUGHOUT THE CARDIAC CYCLE IS THAT YOU CAN RETROSPECTIVELY RECONSTRUCT IMAGES FOR EACH OF THE CARDIAC CYCLE AND GET THIS IN THE IMAGE, SEE THE HEART IN MOTION. HOWEVER WHEN YOU'RE EVALUATING CARDIAC CT IMAGES, MOST OF THE TIME YOU'RE LOOKING FOR CORONARY DISEASE. LOOKING FOR SKEANOSEIS LIKE THIS, THERE'S A SIGNIFICANT KPLEX THERE AND THAT WORKS WITH THE EACH OF THE DIFFERENT PHASES. MOST OF THE TIME THERE'S MOTION ARTIFACT WHERE IT RENDERS THE CORONARY ARTERY, AND THERE'S CERTAIN PHASES OF THE CYCLE WHERE THE MOTION IS STILL, AND THAT'S THE ONLY PORTIONS YOU ACTUALLY USED TO INTERPRET FOR LOOKING FOR STENOSIS. DUE TO THIS AREA WHERE ONLY CERTAIN YOU ONLY NEED AREAS OF THE CARDIAC CYCLE, WHERE DEVELOPMENTS OF THE AREA DELIVERED IS MODULATED BASED ON THE EKG. SUCH THAT WHEN YOU DON'T NEED TO LOOK AT CORONARY VESSELS, THE X-RAY DELIVERED IS LOW, BUT WHEN YOU LOOK AT THE CORONARY ARTERY, THEN HAVE YOU FULL X-RAY POWER AND DIAGMOSTIC CAPABILITY. THE EXAMPLE THAT'S HERE, IN THIS IMAGE, IT'S IN THE IMAGE WHERE THE IMAGE WILL GET GRAINY AND BECOME NONDIAGNOSTIC CORONARY WORK DUE TO IMAGE QUALITY AND THE MOTION AND SEE THERE'S THE RIGHT CORONARY ARTERY THAT STARTS TO BLUR, BUT AT 1 PORTION OF THE CARDIAC CYCLE, HAVE YOU THE HIGH QUALITY IMAGE WE'LL EVALUATE FOR CORONARY DISEASE. A MORE EXTREME FORM OF ECG GAIN SUGGEST TO ONLY ACQUIRE IMAGES AT THAT 1 PORTION AND NOT HAVE THE X-RAY TURN ON FOR THE OTHER PORTIONS. SO ALL YOU GET IS EVALUATION FOR CORONARY ARTERY DISEASE, BUT NOT FOR CARDIAC FUNCTION. HOWEVER THERE'S OTHER WAYS TO LOOK AT CARDIAC MOTION SUCH AS EPICARDIOGRAPHY OR MRI. SO HOW WELL DO THESE NEW TECHNIQUES WORK IN TERMS OF OF ASSESSING CORONARY DISEASE. SO IF YOU LOOK AT THE RETROSPECTIVE ECG, WHICH IS THE TRADITIONAL WAY WHICH IS A LARGE RADIATION EXPOSURE, AND COMPARED TO THE PROSPECTIVE WHERE THE ONLY IMAGE AT THE TIME, A LOOK AT CORONARY ARTERIES, THERE'S A SIGNIFICANT REDUCTION IN RADIATION DOSE, DOWN TO 2 AND HALF. THAT'S JUST BECAUSE THE X-RAY IS ON FOR SHORTER TIME PERIOD. IF YOU LOOK AT THE IMAGE QUALITY OR DIAGNOSTIC ABILITY OF THOSE IMAGES, IT'S ACTUALLY EQUIVALENT OR SLIGHTLY BETTER IF YOU LUES THE NEWER TECHNOLOGY. IF YOU IMAGE THE HEART, YOU WANT TO IMAGE THROUGH THE CORNER OF THE HARE, THIS IS UP THROUGH THE AORTA WHICH IS NOT NECESSARY. SO EXAMPLE HERE AND ONLY SCAN WHAT YOU NEEDED TO. YOU CAN HAVE ABOUT A 30% DOSE SAVINGS. SO THE SECOND REDUCTION STRAIT EDGE SETO DECREASE THE AMOUNT OF X-RAYS DELIVERED TO FORM AN IMAGE. AND THAT'S DONE BY ADJUSTING THE X-RAY 2 VOLTAGE AND 2 CURRENT. THIS IS A SCHEMEATIC OF AN X-RAY TUBE, AND X-RAYS ARE FORMED BY HAVING A HIGH VOLTAGE POTENTIAL BETWEEN THE CATHODE SUCH THAT RELATED TO THE SQUARE AND IT'S NOT A LINGER RELATIONSHIP SO FOR EXAMPLE, IF YOU GO FROM 120 KB WHICH IS PRETTY STANDARD DOWN TO 1 HELPED KB, IT'S ONLY 18% DIFFERENCE IN THOSE, 18% DIFFERENCE IN THE TERMS OF THE SETTING, HOWEVER IT REPRESENTS A 31% SAVINGS IF YOU JUST MAKE THAT 1 CHANGE. OTHER CHANGE CAN YOU MAKE IS THE CURSPENT THAT'S CONTROLLING HOW MANY FOCUSED ON PHOTONS OR X-RAYS GO THROUGH THE PATIENT AND THAT CONTROLS THE IMAGE IS THAT IS A LINEAR RESPONSE TO THE AMOUNT OF RADIATION DOSE, SO IF YOU REDUCE THE CURRENT 20% REDUCE, IT WOULD ALSO REDUCE 20%. AND THIS IS IMPORTANT BECAUSE YOU NEED TO SET THE SETTINGS ON THE CT SCANNER TO BE TAYLORED TO THE SIZE OF THE PATIENT. THERE'S A PICTURE OF THE WORLD'S TALTALLEST MAN AND THE PICTURE WITH THE WORLD'S SHORTEST MAN. AND THEY ARE 2 EXTREMES. YOU DO’IK NOT NEED AS MUCH X-RAYS AS TO IMAGE HIM, SO THERE ARE STANDARD DOSE TABLES FOR EACH MANUFACTURE, WHERE BASED ON BODY MASS INDEX OR BODY WEIGHT OR CIRCUMFERENCE, YOU CAN ADJUST THE TUBE VOLTAGE AND 2 CURRENT AND MAINTAIN DIAGNOSTIC IMAGE QUALITY. SO PUTTING IT ALTOGETHER IN TERMS OF THOSE STRATEGIES, I WAS INVITED TO PARTICIPATE IN A GUIDELINE STATEMENT BY THE CT BASED ON EXPERTISE AND REDUCING RADIATION AND LAST SUMMER, THERE IS A GUIDELINE WHICH PRETTY MUCH DETAILED EACH OF THE DIFFERENT DOSE STRATEGIES, BUT THEN ALSO FOR THE USERS, THERE ARE NUMEROUS DIFFERENT FLOW CHARTS, WHERE YOU GET SUGGESTIONS IN TERMS OF HOW TO SET YOUR SCANNER BASED ON THE HEART RHYTHM, CAPABILITIES OF SCANNER AND PATIENT SIZE. SO HOW WELL HAS NHLBI DONE IN TERMS OF REDUCING RADIATION DOSE. SO EARLIER' DR. ARAI SHOW ED YOU THIS SLIDE WHICH DEMONSTRATED HUGE VARIABILITY OF RADIATION DOSES THROUGHOUT THE WORLD. AND FOR DIFFERENT CT SYSTEMS. IF YOU LOOK AT JUST OVER A YEAR OF CONSECUTIVE STUDIES DONE AT NHLBI, SO 550 CONSECUTIVE STUDIES, ALL COMERS, THIS IS OUR RADIATION DOSE, OUR MEDIAN RADIATION DOSE IS 2 AND HALF CEVERTS OF ALL OF THEM AND THIS IS LOW RADIATION DOSES AND WE ARE 1 OF THE LEADERS IN THE WORLD IN TERMS OF REDUCING RADIATION. IN THE STATE OF MICHIGAN TO PERFORM CARDIAC CT THEIR, YOU HAVE TO BE PART OF THE REGISTRY. SO AS PART OF REGISTRY THERE, THEY LOOK AT ABOUT 5000 PATIENTS AND JUST 15 SITES AND PERFORMING CARDIAC CT AND THEY LOOKED TO SEE, WHAT'S THE RADIATION EXPOSURE FOR THAT BEING DONE BY THAT STATE. AND SIMILAR TO THAT PREVIOUS SLIDE, THERE ARE HUGE RANGES, YOU KNOW GOING FROM ESSENTIALLY 5 MILLI CEVERTS UP TO 50. AND THEY LET THESE SITES PRACTICE THE WAY THEY NORMALLY DO AND THEN HAY HAD EXPERTS GO TO EACH OF THESE INDIVIDUAL SITES, EVALUATE PRACTICE, EDUCATION THEM, HOW CAN YOU REDUCE YOUR RADIATION EXPOSURE? HOW DO YOU IMPLEMENT BEST CLINICAL PRACTICE AND THEN, THEY HAD THEM DO THAT FOR 3 MONTHS AND THEN THEY TOOK ANOTHER SNAPSHOT AND SEE WHAT IS THE RADIATION EXPOSURE AFTER AN INTERVENTIONAL EDUCATION. THIS IS WHAT ITo[[ LOOKS LIKE. SO OVERALL, THE AVERAGE RADIATION DOSE GOT SHIFTED DO THE LOWER RADIATION DOSES. AND JUST THROUGH EDUCATION, THEY WERE ABLE TO REDUCE RADIATION DOSE BY 50%. NOW IF YOU LOOK AT NHLBI THIS, IS WHERE WE SET, SO THE MAJORITY OF OUR CASES ARE IN THE LESS THAN 5 MILLI CEVERT'S RANGE. WE CAN PERFORM THE LOW DOSE STUDIES SO THERE ARE 2 EXAMPLES OF THE VERY LOW DOSE CASES. THIS DOSE IS ABOUT THE DOSE OF 2 TEST X-RAYS TO .2, TO 2 CHEST X-RAYS SO THIS WILL GIVE YOU AN IDEA HOW MUCH RADIATION THAT IS. BUT THEN, THE THIRD AREA I WANT TO TALK ABOUT IS WHAT CAN YOU DO TO MORE EFFICIENTLY USE THE RADIATION EXPOSURE THAT YOU ALREADY HAVE. AND I WANT TO INTRODUCE TO YOU THE CONCEPT WHICH IS REVOLUTIONIZING CT IMAGE RECONSTRUCTION WHICH CAN DECREASE RADIATION DOSES FURTHER BY ANOTHER FACTOR OF 2. AND HERE'S ANOTHER VERY LOW MIDDLE CEVERT THAT'S COMPLETELY DIAGNOSTIC, SO,ITYRATIVE RECONSTRUCTION IS A NEWER CONSTRUCTION METHOD. THE TRADITIONAL CONSTRUCTION METHOD IS CALLED FILTER BACK PROJECTION AND THIS WAS THE ORIGINAL RECONSTRUCTION METHOD WHICH WAS DEVELOPED WHEN DR. HAUNSFELD DEVELOPED THIS SCANNER IN 1982, SO THIS HAS BEEN USED 40 YEARS AND IN SOME KAY--WAYS QUICK. IT WASN'T QUICK WHEN IT TOOK HOURS TO CONSTRUCT 1 IMAGE BUT IT DOES UTILIZE SHORT CUTS, SUCH AS ASSUMPTIONS TO CREATE THE IMAGE. ITYRATIVE RECONSTRUCTION HOWEVER IS A METHOD OF FORMING IMAGE AND WHAT IT DOES, IS THAT THERE IS AN INITIAL RECONSTRUCTION, HOWEVER, THERE'S A MODEL IN THE BACKGROUND WHERE THE COMPUTER WILL TAKE THE RAW DATA FROM THE SCANNER, DO SOME MODELING, SEE WHAT IT EXPECTS OF TO HAVE AN IMAGE LOOK LIKE AND TOM PAIRED TO IT TO AN INITIAL RECONSTRUCTION, IF THE 2 ARE DIFFERENT IT WILL UPDATE ITS MODEL AND RERUN THE RECONSTRUCTION AND THEN AGAIN COMPARE THAT TO WHAT HAS JUST BEEN--WHAT SHOULD BE THE THEORETICAL MODEL, IF IT'S DIFFERENT, IT KEEPS ON ITERATING, KEEPS ON UPDATING RECONSTRUCTION OVER AND OVER. THE EASYST WAY TO REALLY CONCEPTUALIZE THIS, IS IF YOU GET THE NUMBER FROM 1 TO A HUNDRED. YOU KNOW SO IF I SAY, I HAVE A NUMBER IN MY HEAD, LET'S SAY I HAVE THE NUMBER 62, AND YOU MAKE A GUESS FROM 1 TO HUNDRED, YOU MIGHT SAY 25. IF YOU WERE USING FILTER BACK PROJECTION, THAT'S YOUR ANSWER. YOU HAVE 1 SHOT THAT'S IT. 25 IS PRETTY FAR OFF FROM REALITY, WHICH IS 62. HOWEVER WITHITYRATIVE RECONSTRUCTION, IF YOU GAVE THAT INITIAL GUESS OF 25, THE COMPUTER WILL SAY, THAT'S DIFFERENT THAN WHAT I'M EXPECTING, YOU NEED TO BE HIGHER. SO THEN YOU WOULD THEN DO AN ITERATION AND GIVE ANOTHER GUESS AND YOU MIGHT SAY, 50? WELL 50 IS LESS THAN 62 AND THEN, SOW WOULD SAY HIGHER AND YOU KEEP GOING THROUGH THIS. AND YOU MIGHT SAY 75, AND YOU SAY LOWER AND SO, YOU MAKE ALL THESE ITERATIONS UNTIL YOUR RECONSTRUCTION IS STIMULAR TO WHAT IS EXPECTED. SO CAN YOU DO THIS OVER AND OVER. AND YOU GET THE IDEA THAT OVER TIME, YOU CAN ACTUALLY IMPROVE WHAT YOUR ESTIMATION WILL BE. THE DOWN SIDE OF THITYRATIVE CONSTRUCTION AND VERY EXSPEANSIVE. A CT IS USUALLY 512 BY 512 ELEMENTS AND THAT'S JUST ON 1 IMAGE. HOWEVER, MOST CT SCANS FOR EXAMPLE, HEART MIGHT HAVE ABOUT 400 SLICES. SOMITYRATIVE RECONSTRUCTION METHODS LOOK AT EACH PIXEL AND THE INTERACTIONS OF THAT PIXEL WITH EVERY NEIGHBORING PIXEL SO FOR ANY 1 PIXEL YOU CAN HAVE 8 NEIGHBORING 1S ON 1 SLICE BUT THEN 9 PIXELS ADJACENT ON 2 AGISTENT SLICES SO HAVE YOU 26 NEIGHBORING PIXELS AND YOU CAN PRETTY QUICKLY UNDERSTAND THAT THIS CAN BE VERY COMPUTATIONALLY EXPENSIVE BECAUSE TO UPDATE THOSE PIXELS TAKES A LOT OF COMPUTING POWER, BUT THE GOOD NEWS IS THAT, COMPUTATIONAL POWER IS INCREASING, DOUBLING EVERY 2 YEARS. AND NOW, THERE ARITYRATIVE RECONSTRUCTION PACKAGES THAT CAN PRODUCE IMAGES IN A SHORT AMOUNT OF TIME. SO GIVING YOU AN EXAMPLE OF WHATTITYRATIVE RECONSTRUCTION CAN DO. ON THE LEFT IS AN EXAMPLE OF FILTER BACK PROJECTION WITH SCANNED RADIATION DOSE. THIS IS THE SAME IMAGE AT 80% DOSE REDUCTION OR 20% OF THE DOSE AND YOU SEE THAT THE IMAGES IS PRETTY GRAINY AND YOU'RE LOOKING AT A CORNER ANATOMY, YOU HAVE FINE DETAIL AND JUST IT WOULD BE DIFFICULT TO EVALUATE. HOWEVER, IF YOU ADDITYRATIVE RECONSTRUCTION, THIS IMAGE WITHITYRATIVE RECONSTRUCTION, PRETTY SIMILAR TO THE STANDARD RECONSTRUCTION BUT A FRACTION OF THE DOSE. 20% OF THE DOSE. YOU WANT TO LOOK AT THE CORONARY ARTERIES, THIS IS THE SAME STUDY, THIS IS FILTERED BACK PROJECTION, FULL DOSE, FILTERED BACK PROJECTION, ADDITIONAL RECONSTRUCTION AT 20% OF THE DOSE AND THEN,ITYRATIVE RECONSTRUCTION WHERE THE NOISE IS SIGNIFICANTLY REDUCED AND THIS IMAGE PRETTY SIMILAR TO THAT IMAGE AND THAT'S WHAT WE'RE WORKING ON. SO WE HAVITYRATIVE RECONSTRUCTION INSTALLED ON NHLBI SCANNER, OF OUR FIRST 65 CASES, OUR RADIATION DOSE IS 1.2 MILLI CEVERTS, WHICH REPRESENTS A 60% DOSE REDUCTION FROM WHAT I SHOWED YOU PREVIOUSLY. AND JUST 1 MORE QUICK EXAMPLE HERE OF A MILLI CEVERTS STUDY, PERFORMED WITH THE CONSTRUCTION, PATIENT WITH STENOSIS, THEY ALSO IDENTIFIED STENOSIS ON THIS 1, YOU CAN'T SEE IT WELL BECAUSE IT'S BEEN STINTED AND YOU SEE THAT THIRD STENOSIS THERE. SO IN CONCLUSION, DR. ARAI DISCUSSED HOW CTs AT THE HIGH CENTER OF DEBATE DO THE CT SCALES IN THE U.S., THE CARDIOVASCULAR CT REDUCTION HAS BEEN SUCCESSFUL IT HAS ACHIEVED MORE THAN A 10 DOSE. AND LEARNED FROM OTHER PARTS ARE APPLIED TO THE BODY SUCH AS ADMIN, PELVIS AND EXTREMITIES. DR. BLOOM AND NEWMAN ASK ME TO SHARE SLIDES ABOUT EFFORTS, SIMILAR EFFORTS AT THE CLINICAL CENTER, TRACK RADIATION DOSES PERFORMED THERE. AND OVERDATA FROM ABOUT A WEEK, THEY LOOKED AT RADIATION DOSES FOR EACH OF THE DIFFERENT BODY PARTS. YOU LOOK AT BODY CT WHICH IS THE MAJORITY, YOU LOOK AT CARDIAC, CHEST, MUSK LOW SKELETAL AND NEURAL AND THESE ARE THE RADIATION DOSES, THEY BROKE IT DOWN BY BODY PARTS AND LOOKING AT WHAT THE AVERAGE DOSES FOR FOR EACH OF THE BODY PARTS AND WHAT THE MAXIMAL DOSES ARE, THAT HAS OCCURRED. OBVIOUSLY THINGS LIKE BODY IMAGING CAN COVER A LOT OF AREA SUCH AS CHEST AND PELVIS, HAVE HIGHER LEVELS OF RADIATION, WITH OTHER PARTS LIKE THE HEART OR THE BRAIN. AND ALSO LOOKING AT RADIATION DOSES FOR EACH OF THE DIFFERENT CT SCANS HERE AND IDENTIFIED TO SEE IF ANY CTSCANNERS ARE OUT OF LINE COMPARED TO THE OTHER CT SCANNERS. AND AS A QUALITY ASSURANCE MEASURE, THEY HAVE IDENTIFIED OUTLIERS, OF THE 50 MILICEVERTS EXAMS AND IDENTIFIED THESE OUTLIERS WERE BASICALLY FROM 2 DIFFERENT SCANNERS SO BASED ON THIS, THEY CAN GO BACK AND LOOK AT SCANNER AND LOOK AT PROTOCOLS AND SEE IF THEY WERE PROPERTILY SET. --APPROPRIATELY SET. AND IN TERMS OF OVERALL DOSE TRACKING HERE AT THE CLINICAL CENTER, THEY'RE REDUCING DOSES FOR PEDIATRIC PATIENTS AND THEY'RE IN THE PURCHASED--DOSE SAVING SOFTWARE,ITYRATIVE RECONSTRUCTION AND HARDWARE TO REPRESENT EXISTING CT SCANNERS TO DO DOSE REDUCTIONS. WITH THESE QUALITY ASSURANCE MEASURES THEY WILL COMPARE IT TO NATIONWIDE DOSE REGISTRIES SUCH AS AMERICAN COLLEGE OF RADIOLOGY REGISTRY AND THEN THEY WILL TRY TO APPLY WITH PRINCIPLE INVESTIGATORS WITH REDUCTION IN RADIATION DOSES. THANK YOU FOR YOUR ATTENTION. [ APPLAUSE ]