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Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Steven Birnbaum, M.D. Staff Radiologist and Radiation Safety Officer Southern.

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Presentation on theme: "Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Steven Birnbaum, M.D. Staff Radiologist and Radiation Safety Officer Southern."— Presentation transcript:

1 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Steven Birnbaum, M.D. Staff Radiologist and Radiation Safety Officer Southern New Hampshire Medical Center Nashua, New Hampshire Parkland Medical Center Derry, New Hampshire Member, American College of Radiology Blue Ribbon Panel on Radiation Dose in Medicine Member, ACR Blue Ribbon Panel on Radiation Dose in Medicine and Primer on Radiation Safety, Commission in Physics of the ACR

2 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Arthur Schopenhauer Arthur Schopenhauer 19 th Century German Philosopher 19 th Century German Philosopher All truth passes through three stages. All truth passes through three stages. First, it is ridiculed. First, it is ridiculed. Second, it is violently opposed. Second, it is violently opposed. Third, it is accepted as being self-evident. Third, it is accepted as being self-evident. Adapted from Budoff and Shinbane, Cardiac CT Imaging, Springer Verlag, 2006 Adapted from Budoff and Shinbane, Cardiac CT Imaging, Springer Verlag, 2006

3 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Recent Events- 2007: Brenner and Hall Review in NEJM/Published during RSNA 2009: Cedars-Sinai CT Perfusion Overexposures for Perfusion Head CTs 2009: Smith-Bindman et al, Archives of Internal Medicine: Variable Output by 13 fold of SF Bay Area CT scanners 2010: FDA Initiative to Alert Clinicians and Patients about CT Exposure Issues 2010: California Legislation Requiring Dose Data on Reports Text

4 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT –Radiation Risks –What are they? –There are no Answers/Only Extrapolations and Best Guesses –We Dont Know –I am NOT a Physicist

5 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Units of Dosage –Millisievert Measurement of effective radiation dose Different organs in the body have different sensitivities to radiation Effective dose takes into account these differences and averages organ absorbed doses over the entire body Effective dose allows comparison between different types of exams, natural background radiation, and different types of ionizing radiation

6 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Other Units of Radiation Dose Pertinent to CT –C.T. Dose Index (C.T.D.I. w ) Measure of CT Radiation Dose Delivered Manufacturer Requirement for each Scanner Placed on Console Calculated using Reference Phantoms on Single Axial Image –C.T.D.I. vol Adjusts for Scanning Parameters Pitch Beam Width –Dose Length Product (D.L.P.) Calculated from CTDI vol Times Area Scanned Provided on user interface of all scanners Can be converted to effective dose with a table of conversion Standardized dose ranges are used in ACR CT accreditation program –Estimated Dose Can be Grossly Estimated from DLP Using Fudge Factor Heads /Chest-0.017/Abdomen-0.015/Pelvis-0.019

7 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Radiation Dosage and Effect –10,000 mSv- Radiation sickness with immediate illness and death w/i several weeks –1,000 mSv- Immediate radiation sickness, unlikely to cause death – mSv –Clear dose related increasing risk of carcinogenesis –50 mSv- Clearly associated with increased cancer risk and the highest dose recommended yearly in occupational exposure –20 mSv/year averaged over 5 years- Highest recommended allowable dose for radiation workers –3-5 mSv/year- Typical dose rates of uranium miners in Australia and Estimated Radiation Dosages of Common Medical Procedures –Chest X-Ray mSv –Infant VCUG- 0.8 mSv –Head CT- 2 mSv –Chest CT- 8 mSv –CT Pulmonary Arteriogram- 8 mSv –Cardiac Catheterization- 2.5 mSv –Helical Cardiac CT/Male- 8.8 mSv –Helical Cardiac CT/Female mSv –Renal Stone CT - 10 mSv –Low Dose Renal Stone CT- 6 mSv –Abdomen- Pelvis CT- 10 mSv –PET/CT Fusion-20 mSv

8 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT The Scope of the Problem –Over 70 Million CT studies Performed in the U.S. in 2009 –15% of the Volume of Radiographic Procedures –60% of the Estimated Population Exposure from Diagnostic Radiation Comes from CT –Southern New Hampshire Medical Center- 2,000 CT studies in 1985/18,000 in 2006/20,000 + in 2009 –Outsourcing of CT Reading in Off Hours

9 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Clinical Examples From Our Practice –Patient year old with hypercalciuria and multiple episodes of renal colic was noted to have had 14 renal stone CT studies in a four year period. Total estimated dosage- 140 mSv. –Patient year old AIDS patient with multiple Emergency Room visits receives 8 renal stone CT studies and 2 abdomen and pelvis studies in a 2 year period. Total estimated dosage- 100 mSv. –Patient year old patient with multiple visits to the Emergency Room over 5 years receives 5 Head CT studies, 7 Abdomen and Pelvis CT studies, and 5 CT pulmonary arteriograms. Total estimated dosage- 120 mSv. The mammographic equivalent exposure for this 22 year old patient would be view screening mammograms.

10 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Clinical Examples From Our Practice –Patient year old patient has 4 neck CT studies and 3 CT and globus pulmonary arteriogram studies in a one year interval for panic attacks. Total estimated dosage- 60 mSv. –Patient year old female with renal stones and many episodes of renal colic. She had 14 renal stone CTs at one of our hospitals and reports an additional 20 studies done at a tertiary care hospital in Boston. Total estimated dosage- 340 mSv. –Patient year old female patient with multiple episodes of renal colic. She has had 23 renal stone CTs and 73 KUBs at one of our hospitals over a 7 year interval. Total estimated dosage- 370 mSv.

11 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT –Demographics of Frequent Exposure to CT at SNHMC, 11/2008 PATIENT DEMOGRAPHIC NUMBER OF PATIENTS ER Patients/No Insurance/Episodic Care/Multiple Medical Problems 21 Renal Stone Disease 19 Chronic Abdominal Pain w/Normal Imaging 16 Pulmonary Embolus Evaluation 4 Diverticulitis 2 Crohn's Disease 3 RIS Data Mining with Crystal Reports 156

12 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Technical Factors Under Radiologist Control –Bismuth Breast Shields –Initial Scout Views Done in PA Projection in Female Patients –Minimize Technique (mA and kV) in order to Minimize Exposure Manually or Automatically Dose Modulation in One or Multiple Planes Use Shielding After Scout Views with Automatic Dose Modulation –Center Patient in Gantry –Iterative Reconstruction Algorithms –Cardiac CTA Breast Shields Cause Streak Artifact in Distribution of RCA EKG Dose Modulation-Needs Very Low Heart Rates to be Effective –Minimize Body Area to be Scanned –Avoid Dual/Multiphase Imaging when Possible –Decrease Scan Time/Increase Pitch –Spot Check Dose Reports Now Sent to PACS on Most Scanners –Avoid Repeats, Re-does and Extra Images Careful Explanation by the Technologist of Breath Holding

13 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT

14 –Education (!!!!!!!!!!!!!): Spearheaded by Radiologists Radiologists at Each Institution as Champions Radiologists Emergency Physicians Cardiologists and Surgeons Encourage Evidence Based Practice Encourage Use of Non-ionizing Modalities as Alternatives Will the Study Change Management? –Renal/Ureteral Stone CT Studies in Renal Colic

15 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT

16 Patient Identification by Radiologists –Patients Under the Age of 40 –Benign Diagnoses –Use of 50 mSv Lifetime Threshold Dosage Estimate –Review of Imaging Histories by Technologists and Radiologists Empowerment of CT Technologists –Review of Identified Patients by RSO –Flagging of Patient in RIS –Certified Letters to Providers and Patients –Data Mining in RIS Crystal Reports Elimination of Referring Oncologists

17 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Patient Identification by Radiologists –Imaging Consultation Required in Flagged Patients Prior to CT Performance –Index Patient- Three years and No CT Studies, 12 Renal Ultrasounds and 1 One-shot IVP –Regular Imaging Consultation and Excellent Clinician Acceptance

18 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT

19 Investigation of Extreme Exposure by Radiologists –More than 100 mSv Dose Estimate –Notification of Provider and Patient via Certified Mail –Availability of Counseling to Patients by RSO –Empowerment of Patient –Knowledge of Imaging Histories at Other Institutions by Providers and Patients

20 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT

21 Regional and State Efforts at Patient Radiation Protection –Educational Forums –Tool Kits for Hospitals, Imaging Centers and Offices –State Radiology Society Policy Initiative –Inter-specialty Cooperation –Modify Missions of State Radiation Protection Efforts Currently Device and Occupational Exposure Emphasis Change Emphasis to Patient Radiation Exposure Protection Recent California Legislation Requiring DLP on report –Insurance Company Efforts at Radiation Protection Anthem Programs –Tool Kits on Web and on Forest Products –Provider Notification of Frequent Exposure –Pay for Performance Initiatives National Imaging Associates/Magellan –Use of Pre-certification Data to Identify Frequently Exposed Patients

22 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT American College of Radiology Blue Ribbon Panel on Radiation Dose in Medicine –Followed NCRP Report, April, 2007 –Charge: Comprehensive Review of Current Issues, Controversies and Directions of ACR Patient Radiation Protection Efforts –Members Academic and Private Practice Radiologists ACR Staff Members Health Physicists Equipment and NEMA Representatives FDA/CDRH Representative Patient Advocate

23 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT White Paper in May, 2007 Recommendations –…the presumption is yes whether the increased cumulative exposure to ionizing radiation will increase population cancer incidence

24 24 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Results of the SNHMC Radiation Safety Program Results of the SNHMC Radiation Safety Program Year Flagged Patients Had CTs Ordered Year Flagged Patients Had CTs Ordered 15% Cancelled 15% Cancelled 15% Changed to Non-ionizing Modalities 15% Changed to Non-ionizing Modalities 1 Study Performed at Patient Insistence 1 Study Performed at Patient Insistence 30% Done at Clinician Insistence 30% Done at Clinician Insistence 40% Done Following Clinician/Radiologist Consultation 40% Done Following Clinician/Radiologist Consultation Performance Variability Among Radiologists Performance Variability Among Radiologists Just Do It- The Nike Approach Just Do It- The Nike Approach Leave it up to the Technologists Leave it up to the Technologists Active Consultation Results in Fewer Repeat Studies Active Consultation Results in Fewer Repeat Studies

25 Optimizing Patient Radiation Safety in the Era of Multidetector Helical CT Conclusions of the ACR White Paper –Rapid Increase in CT and Certain Nuclear Medicine Studies Over the Last 20 Years May Result in an Increased Incidence of Radiation Related Cancer –We Can Do Something about this NOW Before it is too Late. Is Patient Radiation Exposure in 2010 the Medical Equivalent of Climate Change and Global Warming?


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