AAPM REPORT NO. 53 RADIATION INFORMATION FOR HOSPITAL PERSONNEL Published for the American Association of Physics in Medicine by the American Institute of Physics AAPM REPORT NO. 53 RADIATION INFORMATION FOR HOSPITAL PERSONNEL RADIATION SAFETY COMMITTEE Charles A. Kelsey (Chairman) MEMBERS OF THE TASK GROUP Morris I. Bank (Chairman) Ralph Lieto Jeff Colvin Sam Lott Casmir Eubig Janet Schlueter Mary Fox Douglas Shearer Frances Harshaw Michael Tkacik Hsin M. Kuan Terry Yoshizumi EDITORS Libby F. Brateman Indra J. Das April 1995 Published for the American Association of Physicists in Medicine by the American Institute of Physics DISCLAIMER: This publication is based on sources and information believed to be reliable, but the AAPM and the editors disclaim any warranty or liability based on or relating to the contents of this publication. The AAPM does not endorse any products, manufacturers, or suppliers. Nothing in this publication should be interpreted as implying such endorsement. Further copies of this report ($10 prepaid) may be obtained from: American Association of Physicists in Medicine One Physics Ellipse College Park, MD 20740-3843 International Standard Book Number: 1-56396-480-5 International Standard Serial Number: 0271-7344 ©1995 by the American Association of Physicists in Medicine All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of the publisher. Published by the American Institute of Physics, Inc. 500 Sunnyside Blvd.. Woodbury, NY 11797 Printed in the United States of America RADIATION INFORMATION FOR HOSPITAL PERSONNEL Table of Contents 1. INTRODUCTION . 1 2. RADIATION . 1 2.1 Radiation Terms . 2 3. BACKGROUND RADIATION . 3 3.1 Natural Radiation Sources . 4 3.1.1 External Sources . 4. 3.1.2 Internal Sources . 4. 4. MAN-MADE RADIATION SOURCES . 5 4.1 Diagnostic Uses . 5 4.2 Therapeutic Uses . 6 5. MEDICAL SOURCES OF RADIATION . 6 5.1 Diagnostic Sources . 6 5.1.1 Fixed X-Ray Machines . 7 5.1.2 Portable or Mobile X-Ray Machines . 7 5.1.3 Computed Tomography Scanners (CT) ................................ 9 5.1.4 Radioactive Materials . 10 5.1.5 Laboratory Departments . 11 5.2 Therapeutic Sources . 1 1 5.2.1 Radiation Therapy Machines . 11 5.2.2 Radioactive Sources for Therapeutic Purposes . 12 6. RADIATION PROTECTION METHODS . 13 6.1 Protection Against Radiation . 15 6.1.1 Time . ................................................. 15 6.1.2 Distance ................................................................................. 16 6.1.3 Shielding . 16. 6.2 Protection Against Radioactive Material Contamination . 16 7. RESTRICTED AREAS . .......................................................... 17 7.1 Recognizing Radiation Areas . 17. 8. SPECIFIC INSTRUCTIONS FOR ALLIED MEDICAL WORKERS .... 19 8.1 Housekeeping Personnel . ....................................................... 19 8.2 Security Personnel . 19 8.3 Maintenance Personnel . 19 8.4 Clerical Personnel . 19 9. RADIATION SURVEYS AND PERSONNEL MONITORING . 20 10. RADIOACTIVE MATERIAL PACKAGE RECEIPT . ................ 20 11. RADIATION EMERGENCIES . 21 12. RADIATION SAFETY OFFICER . 21 13. RADIATION AND PREGNANCY ................................................................ 22 14. RADIATION RISKS . 23 15. ACKNOWLEDGMENTS .................................................................... 24 i RADIATION INFORMATION FOR HOSPITAL PERSONNEL List of Figures Figure 1 - Electromagnetic Spectrum ........................................................ 2 Figure 2 - Background Radiation.. ............................................................. 4 Figure 3 - External and Internal Radiation Sources .................................. 5 Figure 4 - Diagnostic X-Ray Machine.. ..................................................... 8 Figure 5 - Fluoroscopy X-Ray Machine .................................................... 8 Figure 6 - Mobile X-Ray Machine.. ........................................................... 9 Figure 7 - CT scanner ................................................................................. 10 Figure 8 - Gamma Camera in Nuclear Medicine ...................................... 11 Figure 9 - Linear Accelerator in Radiation Oncology .............................. 12 Figure 10 - Brachytherapy Sources Used in Radiation Oncology.. .......... 14 Figure 11 - Time/Distance/Shielding ......................................................... 15 Figure 12 - Radiation Warning Sign(s). ..................................................... 18 Figure 13 - Radioactive Source Storage .................................................... 18 Figure 14 - Hospital Personnel Inspecting a Package ............................... 21 Figure 15 - Counseling Pregnant Worker .................................................. 22 List of Tables Table 1 - Radiation Units . 3 Table 2 - Background Radiation Sources . 7 Table 3 - Estimate of Risks ....................................................................... 23 iii RADIATION INFORMATION FOR HOSPITAL PERSONNEL 1. INTRODUCTION X-ray machines and radiation emitting sources are used in hospitals for the diagnosis and treatment of diseases. Some of the hospital employees who work in radiology, nuclear medicine, radiation oncology, and some laboratories are specifically trained in the operation of radiation machines and the handling of radioactive materials and sources. These personnel are called “occupational workers.” Other hospital workers may work around radiation sources, and may be indirectly exposed to radiation during perfor- mance of their normal duties. These employees are “allied medical work- ers” and may belong to nursing, housekeeping, maintenance, security, ship- ping/receiving, and clerical departments. In addition, patient transport, op- erating room, and recovery room personnel may come in contact with brachy- therapy (radioactive implant) and nuclear medicine patients. This booklet is designed to inform allied medical workers about the na- ture of radiation, its use in the hospital, and methods of radiation protection. The major areas covered in this booklet are: • sources of radiation in the medical environment, • radiation protection methods, • instructions for workers, • radiation risks and biological effects, • and radiation exposure and pregnancy. While the potential exposure to allied medical workers from radiation is very low, and the hazard (risk) is usually minimal, all radiation exposure should be kept to a minimum. Further information can be obtained from your Radiation Safety Officer (RSO). Let us begin by defining “radiation.” 2. RADIATION What is radiation? Radiation is a general term used to describe a bundle of energy in the form of electromagnetic waves. Radio waves, microwaves, ultraviolet (UV), x rays, gamma rays, and visible light are all forms of electromagnetic or EM waves. All EM radiation travels at the speed of light, 300,000 km/s (186,000 miles/s). Among all the EM radiations, only light is visible to the human eye. All other EM radiations cannot be seen and special instruments are 1 required to detect the presence of the invisible types of EM radiation. Fig- ure 1 shows the electromagnetic spectrum, a comparison of energies and properties associated with different types of EM radiation. The term radiation also is used to describe very fast moving particles, such as electrons and neutrons. These particles are found in the atom, which is the smallest part of any material. When the energy of the radiation is high enough, it can remove electrons from the atoms or molecules of a substance and is called ionizing radiation. Not all electromagnetic radiation causes ionization. Ionizing radiation can pass through materials, and is also called penetrating radiation. X rays and gamma rays are high-energy ionizing EM radiations and may simply be called “radiation.” In this document the term “radiation” refers to electromagnetic radiation that causes ionization. Penetrating radiations are useful in the diagnosis and treatment of diseases and are part of the backbone of modern medicine. However, because radiation can ionize and excite molecules, it can cause damage to living tissues. Therefore we must take precautions when using and working around it. 2.1 Radiation Terms To detect the presence and measure the amount of radiation, sensitive and specialized instruments are used. Radiation is measured in radiation units: roentgen, rad, and rem. The “roentgen” is a measure of exposure- the amount of ionization in air produced by radiation at a location. The “rad” is the radiation absorbed dose and refers to the amount of energy absorbed by any material from the radiation. The “rem” determines the ra- diobiological equivalent and refers to the biological effect of the absorbed radiation on living things. From a practical, radiation safety concern, these radiation terms are frequently used interchangeably despite their different scientific definitions. FlGURE 1. Electromagnetic Spectrum. 2 The roentgen, rad, and rem represent large quantities of radiation. Be- cause only low levels of radiation are routinely present in the medical envi- ronment to which allied medical workers are exposed, smaller units are used. These are milliroentgen (mR), millirad (mrad) and millirem (mrem), and are one one-thousandth (1/1000) of the roentgen, rad and rem, respec- tively. Most personnel exposures and measurements are