FOR IMAGING PROFESSIONALS Radiation Safety & Protection FOR IMAGING PROFESSIONALS

RADIATION PROTECTION

Objectives Be able to discuss dose limits and typical doses during different radiological procedures Be able to explain the relative risks of radiation Have a knowledge of how to reduce radiation doses, especially to yourselves

Over one year

RADIOGRAPHIC UNITS & IMAGING TERMINOLOGY

Exposure measured in C/kg or Roentgen(R) amount of charge (electrons) liberated per kilogram of Air (Ionization) 1R = 2.58x10-4 C/Kg

ABSORBED DOSE measured in Gray (Gy) or Rad amount of energy deposited/ absorbed per kilogram of tissue 1Gy = 1 Joule/Kg 100 Rad = 1 Joule/Kg 1Rad = 1/100 Gy

EFFECTIVE DOSE - measured in Sieverts (Sv) or Rem - amount of biological damage - gives a measure dose as if received by the whole body - used to equate dose to risk 1Sv = 1 Joule/Kg 100 Rem = 1 Joule/Kg 1Sv = 1/100 Rem

BONE MARROW DOSE (mRad) Typical Doses During Radiographic Exams EXAM BONE MARROW DOSE (mRad) Gonadal Dose (mRad) Male Female Skull 10 <1 C-Spine 20 Chest 2 Abdomen 30 100 200 L-Spine 60 175 400 Pelvis 300 150 Extremity

Typical Doses During Radiographic Exams Technique Dosage Typical mammography exam 30mRem Chest 120Kvp@ 100mAs 360mRem 20mAs 70mRem Abdomen 160mAs 1000mRem During regular CT breast gets 700mRem Low dose mammography 160mRem Generally 1 CT exam is equivalent to 20 mammos

Summary of the National Council on Radiation Protection & Measurements OCCUPATION EXPOSURE 1. Effective Dose Limits. a. Annual 50mSv 5 rem b. Cummulative 10mSv x age 1 rem x age 2. Equivalent Dose Annual Limits for Tissues and Organs a. Lens of the eye 150mSv 15 rem b. Localized area of the skin, hands and feet. 500mSv 50 rem

Summary of the National Council on Radiation Protection & Measurements PUBLIC EXPOSURE (Annual) 1. Effective dose limits, continuos or frequent exposure. 1 mSv (0.1 rem) 2. Effective dose limits, infrequent exposure 5 mSv (0.5 rem) 3. Equivalent Dose Annual Limits for Tissues and Organs a. Lens of the eye 15mSv (1.5 rem) b. Localized area of the skin, hands and feet. 50mSv (5.0 rem) 4. Negligible individual dose (annual) 0.5 mSv (0.05 rem)

Radiographic Examinations Typical Doses during Radiographic Examinations

SOURCES OF RADIATION

SOURCES OF RADIATION

SCATTER RADIATION

PEDIATRICS More radiosensitive than adults due to sensitive cells and developing organs Gonad shielding important Radiographic examinations difficult: Patient movement Exposure technique more critical

Typical Fluoroscopy Equipment setup

Biological Effects of Ionizing Radiation

Effects of Ionizing Radiation

HUMAN RESPONSES TO IONIZATION RADIATION Acute Radiation Syndrome Hematologic Syndrome Gastrointestinal syndrome Central nervous system Local Tissue damage Skin Gonads Extremities Hematologic depression Cytogenic damage EARLY EFFECTS

HUMAN RESPONSES TO IONIZATION RADIATION Acute Radiation Syndrome Hematologic Syndrome Gastrointestinal syndrome Central nervous system Other malignant disease Bone cancer Lung cancer Breast cancer Leukemia Genetically significant dose Lifespan shortening LATE EFFECTS

Effects of Ionizing Radiation Photograph of the patient’s back 6-8 weeks after multiple coronary angiography and angioplasty procedures. Photograph of the injury 16-21 weeks after the procedures. A small ulcerated area is present.

Effects of Ionizing Radiation Photograph of the patient’s back 18-21 months after the procedures. Tissue necrosis is evident Close-up of the lesion shown in C

Effects of Ionizing Radiation Photograph of the patient’s back after Grafting.

Effects of Ionizing Radiation

The probability of occurrance, but not the severity of Stochastic Effects of Ionizing Radiation The probability of occurrance, but not the severity of the effect depends upon dose

cancer birth defects genetic effects Stochastic Effects of Ionizing Radiation cancer birth defects genetic effects

Effects of Ionizing Radiation Based upon studies of Hiroshima atomic bomb survivors, statisticians predict that an effective dose of 10 mSv (1 rem) given to a population of one million would result in 400 additional cancer deaths!

Effects of Ionizing Radiation Radiogenic cancers have a 20+ year latency period Radiologists during the first half of the twentieth century discovered this the hard way

As Low As Reasonably Achievable. A.L.A.R.A. policy Radiation exposure of personnel and the general public should be kept As Low As Reasonably Achievable.

A.L.A.R.A. policy correct exposure factors correct radiographic technique appropriate radiation protection appropriate development/viewing techniques appropriate radiographic positions for examination minimize repeat examinations continuing education

performing fluoroscopy Qualifications for performing fluoroscopy Only a physician or a registered x-ray technologist under the direct supervision of a physician may perform fluoroscopy.

Radiation Protection Staff 3 Basic Categories Time Distance Shielding

General Radiation Safety Reduce of your exposure Increase from the source Make use of available TIME DISTANCE SHIELDING

Time minimize time in radiography or fluoroscopy rooms minimize time spent with patients who are undergoing therapy treatment eg. nuclear medicine procedures, radioactive implants Know Your Protocol Read the procedure through carefully Understand the steps clearly or Have the protocol displayed where you can see it Practice the technique beforehand

This is the Inverse Square Law. Distance The distance between you and the isotope is of paramount importance for high energy emitters and penetrating radiations. The intensity of radiation at different distances is represented by the formula: This is the Inverse Square Law.

The Inverse Square Law.

The Inverse Square Law.

Distance Inverse Square Law - double the distance from the source of radiation - reduce dose by a factor of 4 General rule - 3 meters (approximately 10 ft) from the source of radiation - dose is insignificant

to patients and personnel Methods to reduce dose to patients and personnel Fluoro only when viewing monitor Use pulsed fluoroscopy when possible Use last image hold

Shielding Personal shielding lead aprons - at least 3 - 5mm Pb equivalent provide up to 90% shielding. thyroid / eye shielding during fluoroscopy lead glove (5mm + Pb eq.) if hands are likely to be in the beam Lead drape on fluoro tower provides an additional 90% protection of the remaining 10% from lead aprons above.

Shielding Protective barriers lead glass / acrylic for windows, lead sheets in doors or plaster board walls, brick walls minimize directing primary beam at widows / doors best position to be located during x-ray exposure

RADIATION MONITORING BADGES State law requires that, during fluoroscopy, one badge must be worn outside the apron at the collar level. Some institutions provide additional badges, usually upon request during pregnancy

RADIATION MONITORING BADGES Badge readings are reviewed regularly by the RSO Institutional investigation levels are set below regulatory limits Personnel are notified regularly and badge readings are posted

HEMATO-LYMPHOPOIETIC HIROSHIMA AND NAGASAKI CASE STUDY ON EFFECT OF IONIZATION RADIATION Incidence Mortality ALL TUMORS  Total (%) 9.014 (100%) 5859 (100%) SOLID TUMOR TOTAL 95.5 8612 5529   Digestive system 53.2 4796 3534 Respitory system 11.4 1027 828 Female Breast 5.9 529 141 Female Genitals 9.9 891 402 Male Genital 1.8 160 68 Other solid cancers 13.3 1209 556 HEMATO-LYMPHOPOIETIC 4.5 330

Common sources of radiation for the general population 1,300 Radiation dose, in millirems (mrem), from a single full-body computed tomography (CT) scan 1.5 Miles Distance you’d need to have been from the Hiroshima atomic explosion to receive an equivalent dose 29 Radiation dose, in mrem, from smoking a pack of cigarettes 300 Average annual radiation dose from natural sources, in mrem, per person in the U.S. 1 Average annual radiation dose, in mrem, from eating one or two bananas a week 0.08% Increase in risk of death from cancer after a full-body CT scan 3.75% Increase in risk of death from cancer if you receive a full-body CT scan annually starting at age 25 57 MILLION Number of full-body CT scans performed in 2003 $16 BILLION Estimated annual cost of unnecessary diagnostic imaging 7 Percentage of patients informed of the risks of their CT scans Sources: American College of Radiology, David J. Brenner/Columbia University Medical Center, U.S. Food and Drug Administration, David C. Levin/Thomas Jefferson University Hospital, National Institutes of Health, Nuclear Energy Institute, Yale University School of Medicine

REMEMBER Protect YOURSELVES and the PATIENTS

REFERENCES 1990 Recommendations of the International Commission on Radiological Protection, ICRP Publication 60, Permagon Press, Oxford Brennen S.E. and Putney R.G., eds (1983) Dose reduction in diagnostic radiology, The Hospital Physicist’s Associtaion Plaut S., (1993) Radiation protection in the x-ray department, Butterworth-Heinemann, Oxford Bushong S.C., (2004) Radiological science for technologists: Physics, Biology and Protection, 8th Ed. Mosby, St Louis Faulkner K. and Wall B.F., eds (1988) Are x-rays safe enough? Patient dose and risks in diagnostic radiology, The Institute of Physical Science in Medicine, Report No. 55 Norris, Teresa G., Radiation Safety in Fluoroscopy. Radiologic Technology. Vol 73 No 6, August 2002, 511 Seeram E., (1997) Radiation protection, Lippincott, Philadelphia Sherer, Mary Alice., Visconti, Paul J., Ritenour, Russell.,(2002) Radiation Protection in Medical Radiography, 8th Ed. Mosby, St Louis. Web D.V., Solomon S.B. and Thomson J.E.M., (1999) Background radiation levels and medical exposure in Australia, Radiation Protection in Australia, Vol 16 No 2 pp.25-32