Recently there has been considerable news media coverage regarding high levels of ionizing radiation associated with CT scans. (Parts I and I B) The radiation doses quoted in this paper are not those recommended by the American College of Radiology or the Society of Pediatric Radiology. (Parts II-IV) However; these articles have heightened awareness and fear regarding ionizing radiation.
The following report discusses basic policies and procedures employed to assure safety and security of patients undergoing imaging examination/procedures and for the employees providing these services. These policies and procedures are part of the safety assurances patients can count on when having imaging examinations in an accredited hospital. Explanations of various available imaging techniques, including MR and US, which do not use ionizing radiation to produce an image, are described along with the risks associated with contrast agents occasionally used with imaging studies. The intentions are to inform patients and employees and to improve communication in order to reassure that safety is a priority. The administrative roles and responsibilities for oversight are also briefly outlined. Patients and employees of the institution can use this information to quell the concerns of patients and other providers regarding the safety of various medical imaging procedures.
Safety & Security Procedures within the Department of Radiology & Imaging
The Department of Radiology & Imaging provides for the safety and security of all patients, employees and visitors in regard to medical imaging including interventional procedures performed under imaging guidance and use of contrast agents for enhanced imaging outcomes. At our institution, administrative controls and oversight are in place to establish policies and procedures which assure safety and security.
Each patient is required to have written orders from their physician identifying the requested imaging exam and/or interventional procedure. Custom order forms are generated by the Department and are offered to each referring physician and are encouraged to be used to improve efficiency and decrease the possibility of communication errors.
Correct patient identification is ensured by using two approved specific identifiers, patients must: spell their name and give their date of birth.
Patient Privacy and Dignity
Information regarding imaging examinations and/or procedures is available on the hospital and Department of Radiology website for patients to review.
Each patient is given an individual dressing room. Private restroom facilities are adjacent to the radiographic rooms.
The patient must provide, to the best of his/her knowledge, accurate and complete information regarding all matters relating to their health care, including:
A patient is responsible to make known whether or not he/she clearly understands the reason for the examination/procedure and their role in that process. The patient is also responsible to follow established rules and regulations, especially as they affect patient care. This responsibility includes consideration for the rights of other patients and personnel and respect for their property, and assistance in the hospital's efforts to limit noise and smoking. It is also a patient's responsibility to be mindful of the number and behavior of those accompanying them.
All female patients of child bearing age scheduled for a conventional x-ray, CT, fluoroscopy, MR or non-US image guided interventional procedure are asked if they are or think they might be pregnant. If the possibility of pregnancy exists, the patient is informed of options, risks and alternatives. If pregnant, the patient is informed of the risks and the patient’s obstetrician is consulted.
Ionizing Radiation (Radiology) Modalities
Conventional x-rays use invisible electromagnetic energy-ionizing radiation to produce images of the body, including bones, joints, and soft tissue.
Ionizing radiation is a risk to sensitive tissues (e.g. bone marrow, gonads and thyroid).
Radiation during pregnancy has the potential of producing birth defects so it is important to avoid ionizing radiation if there is a suspicion or actual knowledge of being pregnant. Particular caution should be exercised during the first trimester. A patient who is pregnant or suspects there is a possibility of being pregnant will not be examined without the recommendation of a radiologist and consultation with the attending gynecologist/obstetrician.
Every effort is made to keep radiation exposure as low as practicable. Dosage utilized is according to ALARA (individual and collective doses must be As Low As is Reasonably Achievable).
Radiation dosages for diagnostic imaging examinations are described in terms of mRems and can be presented as entrance dose, skin dose, organ dose, total body dose or “effective dose.” The “effective dose” is the most commonly used terminology and is a calculation that estimates what dose, if given to the entire body, might produce the same approximate amount of risk as would the real dose actually received by the irradiated area. The “effective dose” for a specific examination can be compared to background received just by living in a specific area, such as 300 mRem. received annually in New York City.
The repeat rate (the number of retakes in order to obtain the ordered images of diagnostic quality) is closely monitored. The repeat rate at our institution is low (approximately 3%) compared with the national average (8%). This low rate of repeat examinations is a result of great skill, expertise and training, in addition to familiarity with referring physician’s expectations.
Collimation is a major factor to reduce ionizing radiation exposure; it limits the field of exposure to the area of interest.
All patients receive gonadal shielding provided the shielding does not infringe upon the area of primary diagnostic interest. The department has wraparound, full and half aprons, breast shields, and both male and female gonadal shields (Thyroid Shields).
Fluoroscopy provides real-time X-ray imaging and is used to study moving body structures via a continuous x-ray beam producing a generated image. The image is transmitted to a TV-like monitor so that the body part and its motion can be seen in detail. Fluoroscopy is used for guiding diagnostic and therapeutic interventional procedures, including image-guided anesthetic injections, into joints or the spine, and also to help locate radiopaque foreign bodies.
The risks of ionizing radiation are discussed under conventional x-ray.
All fluoroscopic procedures performed in the Department of Radiology & Imaging are performed by a radiologist, a physician with subspecialized training, and assisted by a technologist. Both are trained in the safe use of ionizing radiation including collimation, ionizing scatter and pulsed radiation techniques to guide interventional procedures. Patient exposures are logged and monitored to be within safety standards.
Computed Tomography (CT)
Computed Tomography (CT) uses ionizing radiation to capture thin section axial images and computer processing to create cross-sectional images of bones, joints, and soft tissues. These axial images are reformatted for multiplanar views.
CT provides highly detailed information of the spine, joints, and soft tissues (including soft tissue calcifications). Additionally, CT provides detailed images related to abnormalities of the abdomen, pelvis or head. CT is usually obtained after myelograms, discograms, and after selected types of arthrograms. Special protocols are used to visualize each area of the musculoskeletal system. CT is also used to guide procedures such as diagnostic and therapeutic interventional procedures including, facet joint injections, nerve blocks, and biopsies.
Risks and Safety Measures:
The risks and safety measures are the same as described under conventional x-ray and every effort is made to minimize dosage. Exposure factors appropriate to patient body size and thickness to minimize dose while optimizing image quality are utilized. Specific pediatric imaging protocols for infants and children are used and based on patient size and weight.
Non-Ionizing Imaging Modalities
Ultrasound or sonogram (US) uses high frequency sound waves to image soft tissues (e.g. tendon, ligaments, neuromas, bursas etc.) and blood flow. US is also used to
guide both diagnostic and therapeutic interventional procedures.
No ionizing radiation is involved. Ultrasound is very safe.
Precautions are mainly for instrument and field sterility and physical safety.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) uses high strength magnets and radio waves to send and receive signals to a specific body part. A computer then converts these signals into images. High resolution MR imaging is used to demonstrate fine detail of articular cartilage, tendons, peripheral nerve, and other soft tissue structures that are not typically demonstrated on routine MR exams.
Because ionizing radiation is not used. MRI is safe in the majority of patients; however, certain patients may not be able to have an MRI. Patients who are at risk during an MRI examination include people suffering from claustrophobia (nervousness in small spaces); people with implanted medical devices such as aneurysm in the brain, heart pacemakers and cochlear (inner ear) implants; and people with pieces of metal close to or in an important organ (e.g. the eye). Any patient who is pregnant or suspects there is a possibility of being pregnant will not be scanned or enter the restricted magnetic field area without the recommendation of a radiologist and consultation with the attending gynecologist/obstetrician. As with ionizing radiation, particular caution should be exercised during the first trimester.
Patient’s specific areas of discomfort/pain are requested in order to verify that the procedure ordered is appropriate for the patient's condition.
To insure that MRI incompatible clothing or jewelry are not present in the MRI field the following precautions are taken:
The MRI technologist reviews the intake form with the patient to insure magnetic safety and verify the patient's symptoms with the scanning protocol to be performed. Patients, relatives, caregivers and other persons accompanying the patient during the MRI exam are also screened and required to fill out an MRI safety questionnaire.
Sample MRI Intake Questions:
Interventional Radiology (IR)
Interventional radiology (IR) is a subspecialty within the field of radiology and implies the use of various imaging techniques (e.g. x-ray, fluoroscopy, CT, and ultrasound) to guide diagnostic examinations and therapeutic procedures. Interventional radiologists are board certified physicians who have special training in minimally invasive, targeted diagnostic examinations and treatments performed using imaging for guidance.
Interventional procedures have less risk, less pain and less recovery time compared to surgery. Risks include potential of infection or bleeding and, in inexperienced hands, risks of exposure to ionizing radiation.
The radiologist reviews the order for the procedure and makes other recommendations to the referring physician if required. Once the procedure is deemed appropriate and necessary, the following protocol is followed:
The consent form is very specific as to the procedure and site. The words “RIGHT” or “LEFT” or “BILATERAL” are spelled out on the physician orders, schedule and the consent form.
When digits (fingers, toes) are involved, the procedure consent form and customized radiology diagram form: “Patient Verification of Side and Site for Interventional Procedure” must be completed.
Before the patient leaves the department, they are assessed by the radiologist/fellow to ensure stability, pain level and state of mind. If the patient feels in any way unwell or in pain, they are encouraged to stay in the department at least until the feeling subsides.
Exception: IV Sedation patients are transferred to Post Anesthesia Care
Unit for monitoring and discharged to home when discharge criteria are met.
Conversion to Inpatient status occurs only if there is an unanticipated response e.g. severe pain. The reasons for admission and the proposed treatment plan will be documented in the patient’s record. The Admitting Department is notified and all relevant “hand off” communications completed. The patient is assigned a medical doctor as per hospital policy.
Post Procedure Follow Up Call: The day after their procedure, patients are contacted by the IR nurse to ascertain their status, reinforce discharge instructions, and ensure contact with the physician if there is any concern.
Radiographic/Imaging Contrast Agents
Radiographic/imaging contrast agents are used to increase sensitivity and specificity of diagnostic accuracy and to help guide and confirm location of diagnostic and therapeutic procedures. Radiographic x-ray contrast agents usually contain barium or iodine. MR contrast agents contain gadolinium. US contrast agents contain microbubbles.
In order for a patient to receive contrast, a written order is required. Contrast assessment and IV contrast agent form is completed by the radiologist/fellow. A power injector, used in CT for the delivery of IV contrast media, is operated by a trained healthcare professional.
Specific Gadolinium Safety Measure (Usage of a Gadolinium Contrast Agent) - Gadolinium is labeled for use for magnetic resonance imaging (MRI). A strict policy regarding the use of gadolinium is used. MRI contrast agents that currently contain gadolinium are Magnevist, MultiHance, Omniscan, OptiMARK, and ProHance.
Although published information provides support for the use of gadolinium as an alternative to iodinated contrast agent in non-MRI examinations, such as CT angiography and for certain interventional procedures, gadolinium is not recommended to be used for an outpatient and/or for a non-emergent scan in a patient with a history of allergy to iodinated contrast agent. In this instance, the patient should be pre-treated with the usual preventive antihistamine and corticosteroid therapy 24 hours prior to the administration of iodinated contrast for the examination.
Gadolinium contrast agent may be used for emergency procedures where the patient has an absolute or relative contraindication to the administration of traditional iodinated contrast agent. Emergent procedures include but are not limited to: A CTA examination to diagnose Pulmonary Embolus or DVT.
Use of Gadolinium by Non-Radiologists
If gadolinium is used on a patient by a non-radiologist and an MRI is subsequently ordered within 48 hours of the administration of the gadolinium, the physician must include on the order form for the MRI both the reason for the MRI exam and specific information.
Patients receiving contrast are monitored for:
Patients will be monitored for mild to severe allergic reactions (e.g. headaches, flush, allergic skin reaction, severe anaphylactic reaction or convulsive attack). Individuals with a history of prior severe contrast reaction will either have the exam performed without contrast or in certain cases
will have it performed with contrast after a course of premedication with steroids and
antihistamine. Patients with known history of contrast allergy are assessed and pre-
medicated per departmental policy. The premedication is started a day or so before the
At the first suspicion of anaphylaxis, the MD is contacted and the airway, breathing
and circulation are assessed. If systemic anaphylaxis (severe allergic reaction) is suspected in adults, EpiPen auto-injector is appropriate for intramuscular injection.
Extravasation - Guidelines for Treatment of Extravasated Contrast Media
The site of swelling from the extravasated contrast will be circled with a marker Patient
is given care instructions of this site. Most patients improve over 24-36 hours. If after
36-48 hours there is continued improvement, the likelihood of any subsequent problems
are very low.
Surgical treatment is only reserved for patients who experience necrosis and skin sloughing which would be evident by this time.
Safety procedures provide confidence that the department maintains a safe environment for patients, visitors, physicians, and employees to prevent accidents or injuries.
Employee Safety Responsibility
The employee is responsible for patient, visitor and fellow employees’ personnel safety and is expected to practice safe work procedures in accordance with the Radiology Department's safety policy. Personnel are expected to:
*An Occurrence Report Form is to be completed if any injury or incident occurs.
Safety with Regard to Equipment Use and Monitoring
All diagnostic x-ray equipment is used under the direction and/or supervision of a diagnostic radiologist. Only trained persons licensed by the New York state Department of Health shall be authorized to make radiographic exposures of a patient.
Ionizing Radiation Protection
All diagnostic radiologic equipment (fixed and mobile) is calibrated by a qualified physicist. Calibrations occur annually, at the least. All equipment is scheduled for preventative maintenance checks by service engineers. Technologists check the equipment before each patient use.
The exposure switch of each fixed x-ray diagnostic unit (x-ray room) has an electrical connection with the door, such that an exposure cannot be made unless the x-ray room door is closed.
Equipment malfunction of any kind requires the patient to be transferred to another x-ray room for completion of the exam. Any malfunction of equipment is to be communicated to department personnel responsible for equipment service.
Whenever possible, mechanical devices only (e.g. tape, velcro straps, etc.) shall be utilized to immobilize patients during radiology procedures. Employees are not to hold children. No radiological (X-ray) technologist or female in the procreating age shall hold a patient. A family member who is not pregnant will hold the child.
The location of the crash carts and other emergency carts are known by all department employees.
New personnel are trained in radiation safety practices such as maximizing the distance and minimizing the time at the radiation source, wearing protective apparel (i.e. lead aprons, gloves, and glasses), and using proper collimation. Annual Radiation Safety In-service with documentation of staff attendance is required.
Lead aprons must be worn by all personnel present during a fluoroscopic examination. All lead gloves, aprons, and gonadal shields are inspected regularly for safety defects.
When using x-ray equipment employees are in an enclosed control booth and behind lead glass.
Occupational Dose Program
Radiation monitoring badges must be worn at collar level by all radiation workers at all times. Distribution and collection of the badges for routine processing will be the responsibility of the Radiation Safety Officer. Results of radiation dose monitoring are reviewed monthly by the radiation physicist, and are available for review upon request.
At no time will a badge be exposed to radiation unless worn by the individual to whom it is issued. Any infraction of this rule may result in the loss of that person's privilege to work with radioactive material and/or ionizing radiation.
Flagrant violations of this policy may result in reprimand, suspension, or termination. The personnel who are subjected to radiation exposure due to radioactive
material will be furnished a thermo luminescent dosimeter to be worn at the collar, and extremity (ring) badge to be worn on the hand most likely to receive the most radiation exposure. The records of exposure reported on these dosimeters will be kept by the Radiation Safety Officer on forms that are in compliance with Article 175.
Radiation Safety of Pregnant Radiation Workers
State Radiation and Nuclear Regulatory Commission regulations require that the fetus of a radiation worker not receive a dose equivalent in excess of 0.5rem (500 mrem or 5 mSv) during the entire pregnancy. Additionally, these regulatory bodies have urged that the monthly fetal dose equivalent not exceed 005rem (50 mrem) over the course of the pregnancy.
When a radiation worker is pregnant, she may notify the RSO and then declare the pregnancy in writing in order for the prenatal exposure limits to take effect.
* If notification is not made in writing, the radiation exposure limits remain at the occupational level of 5 rem per year.
The employee is responsible to inform the department in writing of her pregnancy. A department form letter shall be available to complete. A complete assessment of her radiation exposure potential will be made. Any concerns should be addressed with the RSO, Radiation Physicist or Administrator of Radiology.
The maximum permissible exposure for a declared pregnant worker during the gestation period is: 500 mrems
They will be assigned two badges:
1. One for the whole body whole body, normally worn on the torso, outside the lead apron.
2. A second for the fetus normally worn on the abdomen (under the lead apron). The badges will be exchanged on a monthly basis. Exposures will be monitored to be
maintained at a cap of 50 mrems per month.
3. She will also be given a copy of the NRC's recommended guidelines.
4. She is informed of the risks associated with exposure to the fetus. Periodically, her working conditions are reviewed by the Radiation Safety Officer and Health
Radiation workers who follow proper rules of distance and shielding should never exceed 50 mrems to the abdomen in one month.
1. Always wear lead apron (preferably a wrap-around model) during fluoroscopy, special procedures, and portables.
2. Maintain as much distance between the radiation source and your person as is practicable.
3. Always make sure your body is well within the control booth during radiographic procedures.
Adherence to these rules will enable the pregnant radiation worker to continue present duties with the assurance that the worker's fetus is well protected from radiation effects. Concerns of this policy will be addressed by the Radiation Safety Officer on an individual basis.
Time, shielding and distance are still the practice for proper radiation safety for pregnant or non pregnant radiation workers.
Radiation Safety Rules for Portable Radiography CT & in OR
Only necessary persons during portable radiography procedures are to be in the patient room. All unnecessary personnel are cleared from the area when an
x-ray/fluoroscopy is being used in the area.
Non-Ionizing Radiation Protection
Preventive maintenance is performed on a regular basis by an authorized service engineer. This is a requirement on all ultrasound equipment.
Magnetic Resonance Imaging (MRI)
Scheduled preventive maintenance on the MRI scanner is performed by contracted service personnel.
Restricted Magnetic Field Area
To insure safety of both personnel and the magnet, access to the area around the magnet is controlled. This area includes the magnet room, the control room, the computer room, and all other adjacent rooms within the immediate area. The MRI technologist is responsible for all equipment and personnel entering this area. Because of the effects of the static magnetic field, all personnel and visitors are thoroughly screened for contraindications to MRI before entering the magnetic field area or magnet room. No one with a pacemaker or other implanted device is allowed to enter the restricted magnetic field area.
No metal objects are permitted to be in or on a person when entering the restricted magnetic field.
Guidelines to insure the safety of housekeeping personnel when performing their responsibilities, as well as to insure the protection of the magnet are enforced. Additionally, a plan to correctly handle emergency situations in the magnet room is enforced in order to avoid injury and damage to the magnet.
The Radiation Quality Assurance Committee meets quarterly to monitor the safety program and to make recommendations for ensuring a safe work environment. The members conduct monthly walk through inspection tours and develop programs for the ongoing training of employees. In-service education is given on a regular basis within the department.
The Radiation Safety Committee is a standing subcommittee of the Radiology Department's Quality Assurance Committee that also meets quarterly.
Members include the following representatives:
The Radiation Safety Officer is responsible for observing that the policies and procedures adopted by the Radiation Safety Committee are followed by all of those whose work involves the use of radioactive material and/or ionizing radiation. The Radiation Safety Officer is available for consultation to all persons using ionizing radiations and will supervise decontamination procedures and advise investigators of the necessity for decontamination in an area.
Responsibility of authorized users of ionizing radiation
The authorized user will be responsible for insuring compliance with these procedures in areas under his/her jurisdiction and that new personnel will be instructed as to the
hazards and safety precautions attendant to their work and course of action in emergencies.
Policies and Procedures Regarding Ionizing Radiology
Radioactivity testing & controls
Radiation Surveys – Surveys are conducted by the Radiation Safety Officer or a qualified radiation physicist prior to scheduling routine use in order to determine that no hazard exists to operators or other persons in the area.
Radioactive Waste Disposal Policy & Monitoring - Radioactive waste materials are disposed of in compliance with Article 175, New York City Department of Health. Radioactive waste is placed in storage for decay and then final disposal to normal trash. All waste leaving the hospital facility is monitored for radioactive contamination each day by radiology personnel.
Management of Radiation Emergencies
A radiation emergency is defined as an unforeseen occurrence, either actual or suspected. It involves exposure of, or contamination on or within, humans, the environment or both, by a hazardous amount of ionizing radiation or radioactive material. All radiation emergencies are reported immediately to the Radiation Safety Officer or any member of the Radiation Safety Committee. The Radiation Safety Officer determines what constitutes a hazardous amount of ionizing radiation or radioactive material.
At a licensed and accredited institution, imaging equipment is tested by the city and state Department of Health for safety. Radiologists, as the equipment operators, are specifically trained to assure ultimate safety in the operation of the equipment and in the recognition and treatment of possible adverse reaction. Radiology technologists are also licensed professionals trained in radiation safety and proper use of the equipment and protective gear. Patients are encouraged to research their imaging examinations and ask questions of their imaging providers. The more comfortable a patient is, the better the outcome.
Brenner DJ, Ph.D., D.Sc. and Hall EJ, D. Phil., D.Sc. "Computed Tomography An Increasing Source of Radiation Exposure." The New England Journal of Medicine. November 29, 2007; 357 : 2277-2284.
Boone JM, Geraghty EM, Seibert JA, Wootton-Gorges SL. "Dose Reduction in Pediatric CT: A Rational Approach." Radiology. 2003; 228 : 352-360.
Cody DD, Moxley DM, Krugh KT, O'Daniel JC, Wagner LK, Eftekhari F. "Strategies for Formulating Appropriate MDCT Techniques When Imaging the Chest, Abdomen, and Pelvis in Pediatric Patients." AJR Am J Roentgenol. 2004; 182 : 849-859.
American College of Radiology Appropriateness Criteria: "Conventional and Reduced Radiation-dose Techniques." Radiology. 2003; 229 : 575-580.