Radiation Safety Office 306 Benson School

X-RAY SAFETY TRAINING: The Safe Use of Fluoroscopy Safety information required for persons who work with or near the fluoroscopy unit in Animal Care

Why Training? “Rules and Regulations for Radiation Control” Title B (X-rays). Enforced by SC Department of Health & Environmental Control (SC DHEC)- 4.12.22- Operator Requirements for veterinary X-ray. The safety of the operator and others in the room depends on good practices!!

Training Plan Basic characteristics of x-radiation. Identify types of fluoroscopic units and potential hazards associated with equipment. Biological Effects and Units of dose Personnel monitoring Specific Safety for the Fluoroscope Applicable State Regulations Written operating procedures Actual operation of the unit (PI requirement)

Radiography vs. Fluoroscopy Radiographs are “pictures” of the internal structures where X-rays pass through the body and make an image on film or digitally - one image at a time. Fluoroscopy allows the visualization of movement in the internal structures in real time. The fluoroscopic image is formed on an image intensifier (II) and displayed on a video screen. X-rays are “continuous” as long as the operating switch is on.

Basics Of X-Ray Production Radiographs and Fluoroscopy both use ionizing radiation.

Characteristics of X-rays A form of electromagnetic energy that is generated by an X-ray source/machine. Invisible Due to the energy of the X-rays, they can penetrate the body. They are absorbed more by denser material (bone) than softer tissue. This difference leads to an image of varying light/dark shades where internal structure can be seen.

Electromagnetic (EM) Waves or photons: The electromagnetic spectrum covers a wide range of wavelengths and photon energies. It includes visible light, Radio waves, Microwaves, UV light, X-rays and gamma rays. An excited atom can emit an X-ray or gamma ray to get back to a ground state. The only difference is where the wave originates. Gamma Rays ()- emission of EM from the nucleus to get an atom back to a ground state. X-Rays- Originate from outside the nucleus in electron cloud.

Ionizing Radiation Ionizing radiation has enough energy to remove tightly bound electrons from atoms, and will create Ions. When this ionization occurs in living cells, there could be some consequences to the cells and tissues in the body, depending on the amount of radiation. The cells could either die, repair themselves, or become mutated in some form and become cancerous. There are many variables to the effect the radiation will produce. Because X-rays are considered ionizing radiation, there is an attempt to reduce any unnecessary exposure.

Generating X-rays X-rays are generated in a vacuum tube. Electrons from a cathode accelerate under high voltage towards an anode. When the electrons hit the anode they slow down abruptly and generate X-rays in the process. The X-rays escape out of a window in the tube and become useful.

X-ray Tube Design

X-ray Technique The energy of the X-rays is determined by the voltage applied to the anode (commonly called the kilovoltage or kV). The intensity of the X-rays is determined by the flow of electrons from the cathode to the anode. The electron flow is often called the mAs (for milliamp-second). Together the kV and mAs make up the X-ray technique.

X-ray Technique- kV The kV determines how much energy gets through the subject. Use high kV to penetrate bone, large people, or large boney people. Use low kV to show soft tissues, such as heart and lung. kVs range from about 25 kV for mammography to 150 kV for chest X-rays. Typical fluoroscope kVs are in the 50 kV to 80 kV range.

X-ray Technique- mAs The mAs determines the total amount of radiation used to make an image. In a conventional X-ray the time (s) is very short and the tube current (mA) is fairly large. Fluoroscopy uses a small mA, but exposures may run for several seconds. The result is a moving, but grainy image.

X-ray Technique- kV and mA Typically, the kV is set to penetrate the chosen body part, and the mA is adjusted to give a suitable image. In fluoroscopy this procedure is usually done automatically in a process called auto-fluoro.

The Fluoroscopic Unit

Fluoroscopic Images Compared to conventional X-ray images, fluoroscopic images are grainy. Fluoroscopy images use as little radiation as possible. Less radiation = more noise (image grain) More noise = harder to see fine detail. Fluoroscopy is used for examining large structures or those filled with a contrast agent. Fine image resolution usually not necessary.

Type of Fluoroscopes General purpose fluoroscopes may have the X-ray head under or over the table. Over-table units can be used for general radiology as well. The image intensifier (II) on an under-table unit is called the tower.

Stationary Fluoroscopes X-ray Head Image Intensifier Undertable Fluoro Overtable Fluoro

Other type of Fluoroscopes A C-arm is an x-ray unit with the support structure shaped like the letter “C” between the x-ray tube and the image intensifier. The C-arm permits the physician to rotate and angle the x-ray tube without moving the patient. - Mobile C-arms can roll around. - Mini C-arms are smaller fluoroscopes used only for extremities.

C-ARMS Mobile C-Arm Mini C-Arm

Safety Considerations It is sometimes difficult to use distance to reduce exposure- staff exposure with C-arms can be a problem. Training for all personnel in the room is a must. X-rays are produced only when the x-ray tube is energized- a light indicates when X-rays are on. Never point the instrument at yourself or anyone when the shutter is open. Scatter radiation from the subject can add to total exposure of personnel in the room. Personnel shielding is critical!

Where do you stand during fluoroscopy use? Scattered radiation from the patient is the main source of exposure to staff in the room. Scatter radiation is more intense on the X-ray tube side where the x-rays are being emitted. Personnel should stand on the image intensifier side to reduce the exposure due to scatter.

Proper Positioning Whenever possible, position the X-ray head under the patient. (This isn’t possible on an over-table unit.) The X-ray source (inside the head) must be at least 12” away from the patient’s skin. This is built into most fixed units. C-arms have spacer cones to keep the right distance.

Use of Foot Pedals Fluoroscopes of all types are operated by the use of a foot pedal. When the pedal is depressed, X-rays are emitted. The pedal is a “dead man” switch. The machine will only operate when there is pressure on the switch. As soon as pressure is off of the switch, the X-rays are no longer produced.

Image Intensifier The Image Intensifier (II) converts the X-ray image into a video image. The image can be adjusted for brightness and magnification to view the area of interest. Brighter images require more radiation and possibly more exposure to the operator and ancillary personnel from scatter. The II may be a large vacuum device or a flat panel.

Image Intensifiers Tube device Flat Panel

Biological Effects from Ionizing Radiation

Biological Effects from large doses of radiation Radiation sickness Loss of hair Skin burns Tissue necrosis Death (if dose is high enough) *Generally, these effects can only occur in very rare instances.

Biological Effects from small doses of radiation Carcinogenesis Genetic abnormalities in offspring Damage to developing fetus * These potential effects are the main concerns with any dose received from sources on campus.

Units of Radiation Dose Roentgen Radiation Absorbed Dose (RAD) Roentgen Equivalent Man (REM)

Roentgen (R) A measure of radiation exposure in air. 1R=2.58 x 10 -4 Coulombs/kg of air Used for measurement of X-rays and Gamma Rays only.

Radiation Absorbed Dose (Rad or Gray) The amount of energy from ionizing radiation deposited in any medium (water, tissue, air). Absorbed dose is dependent on: 1. energy of the radiation 2. density of the medium

Radiation Equivalent Dose (Rem or Sievert) A measurement of the biological damage to living tissue as a result of radiation exposure. absorbed dose (Rad)* Quality Factor (QF) where QF is based on the type of radiation since some types of radiation cause more biological damage than others.

Rem (or Sievert) Each type of radiation is assigned a quality factor: x-rays = 1 gamma rays = 1 neutrons = 10-20 alphas = 20 In summary: For x-rays, 1Rad = 1 Rem For alphas, 1Rad = 20 Rem Dose is usually expressed in millirem (mrem) 1 Rem = 1000 mrem

As Low As Reasonably Achievable ALARA Keep doses to employees As Low As Reasonably Achievable This is a radiation safety principle for minimizing radiation doses and releases of radioactive materials by employing all reasonable methods. ALARA is not only a sound safety principle, but is a regulatory requirement for all radiation safety programs.

Three methods of Reducing Exposure Time: the less time spent near a radiation source, the less exposure. With Fluoroscopy, the less time the X-ray beam is on, the lower exposure. Distance: Inverse Square Law applies to X-rays. The more distance between you and the radiation source, the less exposure you will receive. Double your distance and your exposure is decreased by a factor of 4. Shielding: A material that is placed between yourself and the radiation source to absorb radiation. Lead is often used to shield x-rays. Personnel shielding (apron, gloves, and thyroid collars) is used during fluoroscopy procedures to reduce your exposure.

Specific Safety for Fluoroscopy

General Requirements for Personnel All personnel in the room during procedures will wear a .5 mm lead equivalent apron. Thyroid shields may also be required in some instances. Always remember that the apron is not covering all parts of your body. Personnel monitoring will be issued to personnel who need to be in the room during procedures. Prior occupational dose (dose received while employed at another facility) will be requested and documented. Doses from multiple facilities will be documented if you are receiving exposure at a different job.

General Requirements for Personnel Must have a training plan: initial training and annual training by the PI. Training must include safety procedures, the machine functions, and recognizing any problems with the unit. Follow all safety procedures established for the X-ray unit.

Holding of Animals- Safety requirements Holder will use leaded gloves in addition to a lead apron. If possible, keep all body parts out of direct x-ray beam. Keep as far away from x-ray beam as possible. Do not use the same person to hold animals routinely. Staff under 18 not permitted and when practical, pregnant workers should not hold an animal.

Personnel Monitoring Required by SC DHEC for those who may get 10% of the occupational dose. Whole body badge placed on top of the lead apron to get “worse case” exposure- The apron will reduce the exposure to the area covered by the apron. Ring badge worn on hand that is most likely to get in the x-ray beam. The ring badge is worn under the leaded glove.

Personnel Dosimeters Wear them anytime you are using the x-ray device. Place badges where you think the maximum dose will be found. Doses on dosimeter reports are in mrem. They will be exchanged on a bimonthly basis. Don’t take badges home. Leave in an area where they will not get accidently X-rayed. Never intentionally expose badges.

Personnel Dosimeters Don’t tamper with badges Don’t use badge when you are receiving an x-ray or nuclear medicine study Protect device from heat or moisture Contact Radiation Safety Office if you leave USC or change jobs

Personnel Dosimeters Ring Badge Whole Body

Annual Occupational Dose Limits Because your work involves potential exposure to radiation, you are classified as an occupational worker and must receive training. As an occupational worker, there are annual limits established. 5.0 Rem/yr (5000 mrem/yr) total dose from external or internal exposures. You can only receive external dose when working near an x-ray device. 15.0 Rem/yr (15000 mrem/yr) Dose to the eye.

Dose to Embryo/Fetus Declaration of pregnancy is voluntary- USC Radiation Safety has a form which must be completed. If employee declares a pregnancy, an additional badge must be worn under the apron to record dose to the fetus. Dose limit per term (9 months) – 500 mrem Alteration of work activities may be possible. Pregnant workers should not hold animals during fluoroscopic procedures.

Additional Requirements A “Caution- X-rays” sign must be posted on each door leading into the X-ray suite. A “Notice to Employees” RHA-20 OSHA form must be posted in the room which provides your rights as a radiation worker. The measurement of the fluoroscopic output is required annually and must be posted on the control. It must include the name of the person who measured the output and the date conducted. All requirements are based on the State of South Carolina Regulations for Radiation Control- Title B.

Records to Maintain Records showing model & serial numbers of instrument(s) Copies of all correspondence with SC DHEC. Annual calibration measurement/surveys. Personnel Monitoring reports- must be accessible to all personnel who are badged. Training records- Initial (provided through Radiation Safety) and Annual Refreshers (provided by the PI). A written Operating Procedure which includes the general function of the fluoroscopic unit, safety precautions in place, use of personnel shielding, animal holding procedures, declaration of pregnancy policy, and use of personnel monitoring.

Examination Information Call 777-5269 for appointment or you may Email Radsafe@mailbox.sc.edu to schedule a time for the Fluoroscopic Safety exam. Bring: (1) pen or pencil (2) bring student/staff ID or driver’s license Directions to Benson School: go to www.sc.edu/visit/map/ enter “Benson School”.

THANKS FOR PARTICIPATING IN THIS TRAINING CLASS If you have any questions related to radiation safety, please contact us at: 777-5269