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Staff And Patient Radiation Protection Andrés Sinisterra Assistant Radiation Safety Officer for Medicine Safety - Suave….... You are in the driver’s seat, so make it safe….!!! Medical Radiation Doses in the US Have increased ~ 6 times in past quarter century Increase use of computed tomography (e.g.: multidetector spiral CT) Increased Nuclear Medicine procedures More interventional procedures CAUTION X-RAY THIS EQUIPMENT PRODUCES X-RAYS WHEN ENERGIZED CAUTION RADIATION TO BE OPERATED ONLY BY QUALIFIED PERSONNEL A wave is a wave & nothing but a wave! Radiation vs. Radioactivity Radiation Energy in transit in the form of high speed particles and electromagnetic waves. Ionizing Radiation Radiation with enough energy so that during an interaction with an atom, it can remove tightly bound electrons from their orbits, causing the atom to become charged or ionized. Radioactivity Spontaneous transformation of an unstable atom and often results in the emission of radiation. This process is referred to as a transformation, a decay or a disintegration of an atom. External vs. Internal Radiation Exposure External Exposure – X-rays, Diagnostic Procedures. + Internal Deposition – Contamination from nuclear medicine patient undergoing a diagnostic or therapeutic procedure resulting in an ingestion of radioactive materials by the staff. = TEDE Units of Radiation Exposure Roentgen Measure of electrical charge produced in air 1,000 mr = 1R Fluoro @ SSD ~3-10 R/min Rad (Gray) Measure of energy absorbed, usually in tissue or bone. 200 rad = transient erythema 1 Gray = 100 Rad Units of Radiation Exposure Rem (Sievert) Measure of occupational risk (cancer) from radiation exposure 1,000 mrem = 1 Rem 1 Sievert = 100 Rem 5 Rem/yr maximum limit 1 R = 1 Rad = 1 Rem Image Quality Vs Exposure Area of Interest Collimation Calcification of the vas deferens. These bilateral asymmetric calcifications occur in the lower to middle portion of the male pelvis PHOTOELECTRON INCIDENT X-RAY Photoelectric effect occurs when an incident x-ray is totally absorbed during the ionization of the inner-shell electron. The incident photon disappears and the k-shell electron, now called a photoelectron, is ejected from the atom. COMPTON ELECTRON INCIDENT X-RAY ANGLE OF DEFLECTION ' SCATTERED X-RAY <' Compton effect occurs between moderate-energy x-rays and outer-shell electrons. It results in ionization of the target atom, change in photon direction and reduction of photon energy. The wavelength of the scattered x-ray is greater than that of the incident x-ray. INCIDENT ELECTRON EJECTED ELECTRON LEAVES A HOLE TO BE FILLED O Shell N Shell M Shell L Shell K Shell Characteristic X-ray Photons (Characteristic Cascade) Scatter Radiation Scatter Radiation Primary Beam X-Ray Tube Leakage Radiation Leakage Radiation Know Where Your Head Is At……!!! Caudal Coronal Minimum Scatter Maximum Scatter plus Leakage Be aware of critically exposed areas Head and shoulders knees and toes !!!!! Know Where Your Head Is At……!!! The greater the distance the greater the scatter Under Normal mode, there is little magnification with the whole beam used to generate a bright image. Under Mag 1 mode, a smaller beam area is projected to the same II output. The resulting object size is larger, but the image is dimmer due to the less beam input. The ABC system would sense the brightness loss and either boost machine X-ray output, increase tube voltage, or a combination of both. The following Table illustrates the effect of changing FieldOf-View, or magnification modes, for a typical fluoroscopy system Mag Mode (Field-Of-View) ESE (R/min) Increase Factor Normal (9 inch) 1.2 1.0 Mag 1 (6 inch) 2.9 2.4 Mag 2 (4.5 inch) 5.2 4.3 Inverse Square Law (X-Rays & Gamma Rays) For a point source, the intensity varies inversely as the square of the distance from the source. Scattered X-rays 10,000 1 cm 2,500 2 cm 400 5 cm 100 10 cm X-Ray Tube Leakage Radiation 25 20 cm 6 5 4 3 7 8 2 15 mR/hr @ 1 m from edge 3.75 mR/hr @ 2 m from edge 0.42 mR/hr @ 3 m from edge Control Booth = Background Basic Radiation Safety Principles Time Distance Shielding Contamination Control Radiation Exposure Monitoring Whole Body Radiation Badge Collar Radiation Badge Worn Underneath Pb Apron Worn Outside Pb Apron At Neck Level BLACK ICON RED ICON Extremity Radiation Badge Worn on Primary Hand Closest to Radiation Source Collar Radiation Badge Worn Outside Pb Apron At Neck Level Whole Body Radiation Badge Worn Underneath Pb Apron PROTECTIVE EQUIPMENT Get The Lead Out but Watch Your Back !! ALARA Investigational Level I Reducing Patient Dose During Fluoroscopy (And Yours) Get off the pedal!! – Fluoro intermittently Collimate and only expose clinical area Use larger fields when possible (Magnification increases patient dose) Use distance of at least 30 cm for mobile units and 38 cm for fixed installations Use appropriate mA and KVp Reducing Patient Dose During Fluoroscopy (And Yours) Remember the egg timer!!! Be aware of the 5 minute timer (especially in high level mode) Have sufficient beam filtration > 90 KVp requires 2.5 mm Al to 3.5 mm Al @ 130 KVp Fluoro only when necessary Schedule annual QA of equipment As Low ALARA Level I > 10% of the maximum quarterly exposure limit (125 mrem) As ALARA Level II Reasonably Achievable > 30% of the maximum quarterly exposure limit (375 mrem) Dose The amount of energy deposited in any substance by ionizing radiation per unit mass of the substance. It is expressed numerically in rads (traditional units) or grays (SI units). Absorbed Dose Dose Equivalent Deep Dose Equivalent Eye Dose Equivalent Shallow Dose Equivalent Effective Dose Equivalent Committed Dose Equivalent Total Effective Dose Equivalent Absorbed Dose - The amount of energy deposited in any substance by ionizing radiation per unit mass of the substance. It is expressed numerically in rads (traditional units) or grays (SI units). Dose Equivalent - The dose equivalent (H) is the product of the absorbed dose in tissue, the quality factor and all other modifying factors at the location of interest. The unit is the rem (R) or the sievert (Sv). Deep Dose Equivalent (Hd) - Applies to external whole body exposure, means the dose equivalent at a tissue depth of 1 cm or greater. Eye Dose Equivalent - The external dose equivalent to the lens of the eye at a tissue depth of 0.3 cm. Shallow Dose Equivalent (Hg) - Applies to the external exposure of the skin or extremity. The dose equivalent at a tissue depth of 0.007 cm averaged over an area of 1 cm2. Committed Dose Equivalent (HE.50) - The dose equivalent (H) is a given organ or tissue that will be accumulated over 50 years following a single intake of radioactive material. Effective Dose Equivalent (HE) - The sum of the products of the dose equivalent (HT) to each organ or tissue and the weighting factor (WT) applicable to each of the body organs or tissues that are irradiated (HE = ‡” WTHT). Total Effective Dose Equivalent - The sum of the deep dose equivalent for external exposures and the committed effective dose equivalent for internal exposures. Biological Effects of Ionizing Radiation Exposure Cancer (Stochastic Effects, Carcinogenic) The Radiologist The Patient The Fetus Acute Somatic Effects (Non-Stochastic) The Radiologist The Patient The Fetus ( Teratogenic Effects) Mutagenic Effects Radiation Exposure Limits (State of Connecticut Administrative Regulations Sect. 19-24-5) Type of Exposure Rem Per Calendar Quarter Whole body; head and trunk; active blood-forming organs; lens of eyes, or gonads. 1.25 (1,250 mrem) (5.0 rem/yr) Hands and forearms; feet and ankles. 18.75 (18,750 mrem) (75 rem/yr) (7,500 mrem) (30 rem/yr) Skin of whole body. Fetus 7.5 500 mrem Total Gestation (0.5 rem) Conditions For Exceeding Quarterly Doses To Whole Body Total Dose For Any Quarter Total Whole Body Dose Plus All Previous Whole Body Doses < 3.0 rem <= 5 (N-18) rem N= Your Age In Years Prior Dose Must Be On a Clear Record ! ! ! ! ALARA PROGRAM EXISTS ! ! ! ! PREGNANCY DECLARATION Confidential Document Confidential Declaration of Pregnancy The United States Nuclear Regulatory Commission requires in the Code of Federal Regulations Title 10, Chapter I, Part 20.1208, that special consideration be given to limitation of embryo/fetus radiation exposure only in those instances where a woman has declared the pregnancy to the l appropriate representative of the employer (the UCHC). In cases where a pregnancy is not declared tia in writing, the larger occupational exposure limit for the working mother is used as a maximum permissible dose limit. The purpose of this form is to officially notify the employer, through the Medical Director of Employee Health Services, that dose limitation to your embryo/fetus is requested. The information contained on this form will be treated as confidential, and only those n e NRC requires a signed declaration of pregnancy for occupational workers to limit exposures to 500 mrem/9months or 50 mrem in any one month. directly involved in assessing the potential for embryo/fetal exposures will be informed. Please sign the form where indicated and forward to: if d n o C Marcia Trape-Cardoso, M.D., Medical Director Employee Health Services MC-6210 I, _________________________________ ______ , formally declare my pregnancy and request dose limitation to my embryo/fetus such that my total radiation exposure during the gestational period does not exceed 500 mrem, and if exposed, received at a uniform rate of no more than 50 mrem per month. As required by the Nuclear Regulatory Commission, my approximate date of conception was __________________. Signed: Department: Telephone #: c:\flw\pregwrk.pre ( rev. 10/2000 ) Date: Are we at risk of danger? Background Equivalent Radiation Time Typical Effective Doses And Bert Values For Some Common X-Ray Studies To An Adult (Adapted From Ipsm Report 53) 5 Effective Dose (mSv) BERT (time to get same dose from nature) Dental, intra-oral 0.06 1 week Chest x-ray 0.08 10 days Thoracic spine 1.5 6 months Lumbar spine 3 1 year Upper GI series 4.5 1.5 years Lower GI series 6 2 years X-ray Study Radiation Exposures From ? Smoking a pack and a half of cigarettes a day will add about 1,300 mrem/year to one's effective dose Flying from New York to London results in the absorption of an extra 2-3 mrem of cosmic radiation 6-8 mrem from NY to Japan International Space Station ? .11 mrad/d to .35 mrad/day 1,980 mrad to 6,300 mrad for 180 day mission Radiation Exposures from Consumer Products 1 # Of People in U.S. Exposed (in millions) Avg. Annual Dose Equivalent to Exposed Population Part of Body Exposed Television Receivers 230 < 1 mrem Whole Body Video Display Terminals 50 < 1 mrem Whole Body Luminous 3 H in Watches and Clocks 11 0.1 mrem Whole Body Luminous 147 Pm in Watches and Clocks 8 0.04 mrem Whole Body 120 7 mrem Whole Body 4 mrem Whole Body & Gonadal Dose Source Building Materials Highway and Road Construction Materials 1 Adapted from NCRP 95 5 Radiation Exposures from 1 Consumer Products # Of People in U.S. Exposed (in millions) Avg. Annual Dose Equivalent to the Exposed Population Part the Body Exposed 2 Tobacco Products 50 16,000 mrem BEDE Domestic Water Supplies 230 15 - 90 mrem BEDE Fertilizer Products 200 0.5 - 5 mrem Natural Gas Heaters 16 22 mrem WB and IDF BEDE Natural Gas Cooking Ranges 125 5 mrem BEDE Dental Protheses 45 700 mrem BMDE Opthalmic Glass 50 4000 mrem CGDE Gas Mantles 50 0.2 mrem WB and SODE Source 1 Adapted from NCRP 95 2 BEDE = Bronchial Epithelial Dose Equivalent; WB = Whole Body; IDF = Ingestion Dose from Foods BMDE = Bronchial Mucosa Dose Equivalent; CGDE = Corneal Germinal Dose Equivalent; SODE = Selected Organ Dose Equivalent Risks which Increase Chance of Death by 1 in 1 million a Smoking 1.4 cigarettes Drinking 1/2 liter of wine Spending 1 hour in a coal mine Spending 3 hours in a coal mine Living 2 days in New York or Boston Traveling 6 minutes by canoe Traveling 10 miles by bicycle Traveling 300 miles by car Flying 1000 miles by jet Flying 6000 miles by jet Living 2 months in Denver on vacation from N.Y. Living 2 months in average stone or brick building One chest x-ray taken in a good hospital Living 2 months with a cigarette smoker a Cancer, Heart disease Cirrhosis of the liver Black lung disease Accident Air pollution Accident Accident Accident Accident Cancer from cosmic radiation Cancer from cosmic radiation Cancer from natural radioactivity Cancer from radiation Cancer, Heart disease B.L. Cohen and I.S. Lee, ”Catalog of Risks Extended and Updated”, Health Physics, Vol. 61, Sept. 1991. More Risks which Increase Chance of Death by 1 in 1 million a Drinking Miami drinking water for 1 year Cancer from chloroform Drinking 30, 12 oz. cans of diet soda Cancer from saccharin Living 5 years at site boundary of a typical nuclear power plant Cancer from radiation in the open Drinking 1000, 24 oz. soft drinks from banned plastic bottles Cancer from acrylonitrile monomer Living 20 years near PVC plant Living 150 years within 20 miles of a nuclear power plant Cancer from vinyl chloride (76 standard) Cancer from radiation Eating 100 charcoal broiled steaks Cancer from benzopyrene Risk of accident by living within 5 miles of a nuclear reactor for Cancer from radiation 50 years Eating 40 tablespoons of peanut butter Liver cancer from aflatoxin B a B.L. Cohen and I.S. Lee, “Catalog of Risks Extended and Updated”, Health Physics, Vol. 61, Sept. 1991. Estimated Loss of Life Expectancy from Health Risks Health Risk Average Days of Life Expectancy Lost Smoking 20 cigarettes/day Overweight (by 20%) All accidents combined Auto accidents Alcohol consumption Home accidents Drowning Natural background radiation Medical diagnostic x-rays All catastrophes (fire, flood, etc.) 1,000 mrem (1 rem) occupational radiation dose 1,000 mrem (1 rem)/yr for 30 years 2370 (6.5 years) 985 (2.7 years) 435 (1.2 years) 200 130 95 41 8 6 3.5 1 30 Note: Average U.S. occupational radiation dose is estimated at 0.34 - 0.65 rem/year. PROGRAM FOR IMPLEMENTING PATIENT INFORMED CONSENT AND FOLLOW UP REGARDING HIGH DOSE SPECIAL X-RAY PROCEDURES Purpose: There are certain x-ray guided procedures that could result in the delivery of a radiation dose to an area of a patient’s skin of sufficient magnitude to produce clinical symptoms. This program was developed to inform patients of this potential risk prior to such procedures, determine if a procedure may lead to a large skin dose and to follow up with the patient if there is a possibility of a skin reaction. Policy: This program is applicable to personnel involved with the following x-ray guided procedures: Percutaneous Transluminal Angioplasty Radiofrequency Cardiac Catheter Ablation Vascular Embolization Stent and Filter Placement Thrombolytic & Fibrinolytic Procedures Percutaneous Transhepatic Cholangiography and/or Biliary Drainage Policy (continued): Endoscopic Retrograde Cholangiopancreatography Transjugular Intrahepatic Portosystemic Shunt Percutaneous Nephrostomy Urinary/Biliary Stone Removal Or Any other x-ray guided procedure that could expose the same area of the skin for more than 30 minutes Policy (continued): For such cases, the patient must be informed in writing prior to the procedure of the risks associated with large x-ray skin doses. Appropriate follow up must be made, if after completion of a procedure, a large skin dose is possible. 1. Document the total x-ray “ON” time, not the duration of the procedure 2. For procedures with total x-ray “ON” time exceeding 30 minutes, determine what body area may have been exposed for the greatest duration and ESTIMATE the maximum fraction of the total “ON” time this occurred. 3. If the total x-ray “ON” time exceeded 30 minutes and the same area of the skin was irradiated for 30 minutes or longer, notify the Radiation Safety Office (2250). 4. The Radiation Safety Officer (or delegate) will estimate the maximum skin dose for the procedure. 5. The Radiation Safety Officer will provide a report to the interventionalist indicating the maximum estimated skin dose. 6. The interventionalist, upon receiving the RSO’s report, shall notify the patient or the patient’s referring physician if the possibility of a skin reaction exists. 7. The referring physician and/or interventionalist will provide treatment instructions to the patient as is medically necessary. Prior to a procedure, the patient should be asked about previous fluoroscopic interventions. Connective tissue diseases (e.g. scleroderma, lupus erythematosus, mixed connective tissue disease), diabetes mellitus, hyperthyroidism and the homozygous form of ataxia telangiectasia have been associated with an increased sensitivity to radiation [9]. Some chemotherapy agents are also known to increase radiation effects. The history should include these risk factors. The patient should be advised about the potential higher risk . To avoid injuries when using an oblique or lateral beam projection, the patient's arm must be secured away from the primary beam. Direct exposure of the female breast, especially entrance-beam exposure, must also be avoided. Radiation Biology Radiosensitivity of Cells 1 As cells mature they become less sensitive to radiation As metabolic rate increases cells become more sensitive to radiation As reproductive rate increases cells become more sensitive to radiation Cell types that are most sensitive to radiation include lymphocytes and stem cells Cell types that are least sensitive to radiation include muscle and ganglion cells 1 Adapted from The 1906 Law of Bergonie and Tribondeau Various degrees of sensitivity to radiation exist due to the type of tissue which receives the exposure Radiosensitive Radioresistant Breast tissue Heart tissue Bone marrow cells Large arteries Mucosa lining of small intestines Large veins Sebaceous (fat) glands of skin Mature blood cells Immune response cells Neurons All stem cell populations Muscle cells Lymphocytes Radiation Induced Skin Injuries TABLE 1. REPORTS RECEIVED BY FDA OF SKIN INJURY FROM FLUOROSCOPY Type of Procedure with Injury Report Number of Injuries RF Cardiac Ablation 13 Catheter Placement for Chemotherapy 1 Transjugular Intrahepatic Portosystemic Shunt (TIPS) 3 Coronary Angioplasty 4 Renal Angioplasty 2 Multiple Hepatic/Biliary Procedures 3 Percutaneous Cholangiogram with Multiple Embolizations 1 * Food and Drug Administration, USA, Internet Site. Radiation Induced Skin Injuries TABLE 2. EXAMPLES OF SKIN INJURIES FROM FLUOROSCOPY * Patient Sex Age Procedure A Male 40 Coronary angiography & PTCA, followed by 2nd coronary angiography B Female nag RF catheter ablation C Female 25 RF catheter ablation Skin breakdown 3 weeks post procedure D Female 34 RF catheter ablation Draining skin lesions on back 3 weeks after procedure E Female 62 Balloon ablation bile duct Burn-like injury on back Anastomosis requiring a skin graft F Female 61 Renal angioplasty * Food and Drug Administration, USA, Internet Site. Injury Skin necrosis requiring 12x10 cm skin graft Second degree burn (7.5x12.5 cm) Skin necrosis requiring graft Radiation Induced Skin Injuries TIME TO THRESHOLD EFFECT THRESHHOLD DOSE, Rad NORMAL 5 R/MIN HIGH 20 R/MIN TIME TO ONSET Early Transient Erythema 200 0.7 hr 0.17 hr Hours Temporary Epilation 300 1.0 hr 0.25 hr 3 Weeks Main Erythema 600 2.0 hr 0.50 hr 10 Days Permanent Epilation 700 2.3 hr 0.58 hr 3 Weeks Dry Desquamation 1,000 3.3 hr 0.83 hr 4 Weeks Moist Desquamation 1,500 5.0 hr 1.25 hr 4 Weeks Late Erythema 1,500 5.0 hr 1.25 hr 6 – 10 Weeks Dermal Necrosis 1,800 6.0 hr 1.50 hr > 10 Weeks Radiation Induced Skin Injuries TIME TO THRESHOLD EFFECT THRESHHOLD DOSE (Gy) NORMAL 5 R/MIN HIGH 20 R/MIN TIME TO ONSET Early Transient Erythema 200 0.7 hr 0.17 hr Hours Temporary Epilation 300 1.0 hr 0.25 hr 3 Weeks Main Erythema 600 2.0 hr 0.50 hr 10 Days Permanent Epilation 700 2.3 hr 0.58 hr 3 Weeks Dry Desquamation 1,000 3.3 hr 0.83 hr 4 Weeks Moist Desquamation 1,500 5.0 hr 1.25 hr 4 Weeks Late Erythema 1,500 5.0 hr 1.25 hr 6 – 10 Weeks Dermal Necrosis 1,800 6.0 hr 1.50 hr > 10 Weeks Free Radical Production from Irradiated Water H2O H2O H2O + e H2O OH + OH H2O + + e H + + OH H2O H + OH H2O2 Stochastic Effects (by chance) Health effects that occur randomly. Effects that occur by chance, generally occurring without a threshold level of dose, whose probability is proportional to the dose and whose severity is independent of the dose. . (examples: cancer incidence and genetic effects) Stochastic Effects (by chance) 1,000,000 persons buy a lottery ticket for $1,00 each. 999,999 persons will not get the large prize. Only one will win the BIG ONE. Return on scratch tickets is not certain. Nonstochastic (Deterministic) Effects Health effects that can be induced upon reaching an apparent threshold, and their severity varies with the radiation dose. examples: cataract in the lens of the eye, non- malignant damage to the skin Nonstochastic (Deterministic) Effects 100 persons invest $1,000 at 5% interest Each person will receive $1,050.00 Return is certain So....., how really dangerous is this so called “RADIATION??” Industrial Radiation Accident An example of a skin injury attributable to x-rays from fluoroscopy is shown in Figure 2. This case, patient A in Table 2, is that of a 40-year-old male who underwent coronary angiography, coronary angioplasty and a second angiography procedure due to complications, followed by a coronary artery bypass graft, all on March 29, 1990. Source: Thomas B. Shope, Ph.D. (HFZ-140) FDA/Center for Devices and Radiological Health Figure 2(a). Condition of patient's back six to eight weeks following multiple coronary angiography and angioplasty procedures Source: Thomas B. Shope, Ph.D. (HFZ-140) FDA/Center for Devices and Radiological Health Figure 2(b). Appearance of skin injury approximately 16 to 21 weeks following the procedures with small ulcerated area present. Source: Thomas B. Shope, Ph.D. (HFZ-140) FDA/Center for Devices and Radiological Health Figure 2(c). Appearance of skin injury approximately 18 to 21 months following procedures, evidencing tissue necrosis. Source: Thomas B. Shope, Ph.D. (HFZ-140) FDA/Center for Devices and Radiological Health Figure 2(d). Close-up view of lesion shown in 2(c). Source: Thomas B. Shope, Ph.D. (HFZ-140) FDA/Center for Devices and Radiological Health Figure 2(e). Appearance of patient's back following skin grafting procedure. Source: Thomas B. Shope, Ph.D. (HFZ-140) FDA/Center for Devices and Radiological Health Transjugular Intrahepatic Portosystemic Shunt This patient received 3 TIPS procedures within a week month 23 22 610 month 7.5 month Source: Koening, Wagner, et al., University of Texas Health Science Center Radiofrequency Cardiac Catheter Ablation Tissue necrosis 5 months after procedure, and deep ulceration with exposure of the humerus at 6.5 months Source: Koening, Wagner, et al., University of Texas Health Science Center Remember ....!!! Following Proper Protection Procedures Minimizes Unnecessary Exposures The End