What is the policy on holding patients during diagnostic imaging procedures?
The regulations (California Code of Regulations Title 17) state:
“No individual occupationally exposed to radiation shall be permitted to hold patients during exposures except during emergencies, nor shall any individual be regularly used for this service. If the patient must be held by an individual, that individual shall be protected with appropriate shielding devices such as protective gloves and apron and he shall be so positioned that no part of his body will be struck by the useful beam.”
The interpretation of this regulation is that occupational workers shall not routinely hold a patient, but can, in unusual cases, provided that they are protected with appropriate shielding. A non-occupational worker, such as a mother or father, can hold the patient. There is some flexibility in the regulations on how an emergency would be defined.
Exemption issued by California for positioning a patient or fluoroscopy Equipment
The exemption permits staff operating under the direct oversight of a licentiate in possession of either current and valid Fluoroscopy Supervisor and Operator permit or a current and valid Radiology Supervisor and Operator certificate (“permitted licentiate”) issued by the Department, are hereby granted an exemption to requirements provided that all of the following conditions are met:
- Positioning the patient or the fluoroscopic equipment by non-permitted individuals shall be performed at the request of a permitted licentiate who is physically present and personally directs such actions.
- The permitted licentiate shall document all actions the non-permitted individuals will perform.
- The permitted licentiate shall document the following:
- Equipment set up and operation;
- Fundamentals of radiation safety;
- Significance of radiation dose, to include hazards of excessive exposure to radiation, biological effects of radiation dose, and radiation protection standards;
- Expected levels of radiation from fluoroscopy equipment;
- Methods of controlling radiation dose: time, distance, shielding; and
- Characteristics and use of personnel monitoring equipment.
- Fluoroscopy equipment being operated is operated only in the automatic exposure control (AEC) or automatic exposure rate control (AERC) mode.
- The permitted licentiate shall review and approve, before exposure of the patient to X-rays, any changes to the spatial relationship and technical factors that resulted from the actions taken by the non-permitted individual.
What are the lead apron requirements when using and fluoroscopes?
- Persons closest to the unit (generally those with “hands on” the patient) should wear a lead equivalent apron when operating the unit.
- Dose rates of greater than 5 mrem/hr can be measured within 6 feet of the table, including where the fluoroscopist stands.
- Wear a lead apron of at least 0.25 mm lead equivalence, with 0.5 mm being the recommended. Additionally, a thyroid collar and leaded eye wear (or “radiation glasses”) are recommended.
- Because radiation exposure drops off very quickly, other personnel in the room do not need to wear lead aprons but should also maintain as much distance from an operating unit as feasible. Radiation exposures 6 feet away are near natural background radiation levels.
- Only necessary personnel should be in the room when the unit is operating. However, for ALARA purposes (i.e., to keep exposures As Low As Reasonably Achievable) keep a portable lead shield between the unit and other personnel in that room performing procedures unrelated to the fluoroscopes unit.
What are the criteria for patient gonadal shielding for radiation protection purposes?
For patients, the gonads may or may not need to be in the primary x-ray field. If the gonads are not in the primary field, the radiation exposure drops off rapidly. In practice, the patient may be provided with a leaded apron anyway, because the staff has been trained to do that or it provides reassurance to the patient.
For situations where the gonads are in the primary radiation field, shielding should be employed as long as the areas of interest are not blocked by the shielding. An example might be to image the pelvis to evaluate the heads of the femur bones. For males, the testes are easily shielded by special shields that are in contact with the body. Alternately, shadow shields can be used. These are typically triangular pieces of lead that are suspended by flexible arms (like those for desk lamps) from the x-ray tube housing. Since the collimator light field is aligned to the x-ray field, the shadow cast by the suspended piece of lead will show what area is being shielded from the x rays produced. For females, the gonads are not visible or generally localized in the abdomen. As such, shielding is seldom employed for females, but the x-ray field collimators may be used to shield the center of the abdomen.
How effective are thyroid shields in protecting the radiation worker from unnecessary exposure? At what dose level do you recommend using a thyroid shield?
A typical 0.5-mm lead-equivalent apron or thyroid shield will provide 85% to 95% attenuation of scattered fluoroscopy x-rays. Thyroid shields are designed for fluoroscopy x-rays and can not shield radioisotopes such as 131I or 18F.
A patient treated with radioiodine (131I) has renal failure and is on dialysis. What radiation safety points should I be aware of?
There is some potential for contamination with these procedures, although it is not excessive and it depends on the administered activity and the length of time from the administration to the dialysis procedure. Administering the radioiodine immediately after dialysis will maximize the time for elimination of the excess radioiodine from the body prior to the next dialysis. The dialysis staff will already be using universal precautions to protect themselves from the patient’s blood and other body fluids. These are the same precautions that are used to protect against contamination from radioactivity. Flushing of the waste from the dialysis tubing directly to the sanitary sewer line and collecting the dialysis tubing and filter as radioactive waste is appropriate. Contact Nuclear Medicine or Health Physics to collect the dialysis tubing and filter.
What are hospital attending staff radiation safety precautions for patients receiving Samarium (153Sm) palliative therapy?
Because 153Sm is mostly a beta particle-emitting radionuclide and beta particles are effectively shielded by the human body, 153Sm does not present an external radiation hazard. However, 153Sm is excreted through the urine for up to three days. Use universal precautions when handling collected urine or urine soiled linens. Urine can be disposed of in the sewer.
Does a resident or fellow need a fluoroscopy permit?
No. A resident or fellow working under the supervision of a Certified Fluoroscopy Supervisor physician does not need to be themselves certified.
When is a Fluoroscopy Supervisor certificate/permit not required?
A physician is not required to obtain a certificate or permit from the State if that physician:
- Requests an x-ray examination through a certified supervisor and operator.
- Performs radiology only in the course of employment by an agency of the Federal Government and only at a Federal facility (Note: As a best management practice, the Veterans Affairs Palo Alto Health Care System complies with the State of California certificate requirements).
Can an ultrasound or echocardiography be performed after a nuclear medicine study?
Radiation exposure from nuclear medicine patients to hospital staff varies depending on the type of radiopharmaceutical, how much was administered and when it was administered. The half-life of nuclear medicine radiopharmaceuticals, that is the time it takes for the radioactivity to drop by half, is typically in the two-to-six-hour range, although the half-life can be longer.
Sonographers work in close proximity to patients which is why it is reasonable to ask what kind of radiation exposure they might be getting from nuclear medicine patients. Because nuclear medicine patients might undergo additional examinations, other hospital staff might also be exposed. The question of “how much radiation exposure” has been researched by direct measurement and reported in publications including the National Council on Radiation Protection & Measurements (Reports No. 124/105).
The Journal of Nuclear Medicine Technology (Volume 23, issue 3, pg. 186-187) published results from a study on radiation exposure to sonographers from patients who were injected with the PET (positron emission tomography) imaging radiopharmaceutical 18F-fluorodeoxyglucose (FDG). The conclusion was that the radiation exposure to the sonographer was usually minimal; if there is daily contact with nuclear medicine patients, radiation risks should be assessed. Monitoring for several months may be appropriate. Scheduling patients several hours after their nuclear medicine procedure is a good practice as well as asking the patient to void before the secondary examination.