Radiation Safety Program

Occupational Dose Limits and Radiation Exposure Controls

• The limits for occupational exposure from ionizing radiation devices (NAC 459.325):
  
  • Whole body (total effective dose equivalent): 5 rem/year
  • Sum of individual organs or tissue: 50 rem/year
  • Eye dose (lens of eye): 15 rem/year
  • Skin or any extremity: 50 rem/year
  • Dose to embryos of declared pregnant woman ("declared pregnant woman" means a woman who has voluntarily informed her supervisor, in writing, of her pregnancy and the estimated date of conception. The declaration remains in effect until the declared woman withdraws the declaration in writing or is no longer pregnant. Note: An average American receives a total of 620 mrem/year about 300 mrem from natural background radiation and 320 mrem from medical exposures to radiation.): 0.5 rem for the entire pregnancy
  • Minors: 10% of above limits
  • Member of public: 0.1 rem/year
• ALARA limits at TMCC is 10% of the annual occupational exposure limits. If an employee's dose exceeds the ALARA limits during a dosimeter wearing period, they may be requested to review/change procedures for ways to reduce future exposures.
• If occupational doses from X-ray device(s) exceed the ALARA limits, the RSO will conduct an investigation into the probable cause of the dose, possible exposure to non-monitored personnel or the public, and methods to reduce future exposures.
• Persons under 18 years of age are not allowed to enter a controlled area during an X-ray device operation unless approved by the RSO.
• Operators are not authorized to hold or support a patient or an animal in direct primary beam path during a radiography exam without personal protective equipment.
• No X-ray device(s) shall produce radiation in such a manner as to create in any non-controlled area in excess of 2 mrem/hour; or radiation levels which, if an individual were continuously present in the area, could result in a dose in excess of 100 mrem/year.
• No one except the patient, the responsible practitioner when medically necessary, the operator or operators-in-training may be present in the radiation device facility during the radiation procedure without prior RSO approval.
• A patient is not a member of the public when undergoing a procedure involving the use of radiation.
• The exposure levels for students in TMCC programs per the ALARA recommendations will not exceed 0.1 rem/year of radiation.

Radiation Protection Practices (Training, Monitoring and Shielding)

Regulation Safety Training

• Users of X-ray device(s) shall be appropriately trained in radiation safety and equipment operation and applicable regulations prior to beginning work with the device.
• All individuals working in or frequenting any portion of a controlled radiation area shall be informed of the occurrence of radiation in the area; and shall be instructed in the radiation safety associated with exposure to such radiation and in provisions, precautions or devices to minimize exposure.
• Training topics include:
  • Characteristics of ionizing radiation
  • Radiation sources
  • Radiation measurement
  • Effects of exposure to radiation
  • Risks associated with occupational and non-occupational exposures
  • Effective dose limits and determinations
  • Application of the principle of ALARA
  • Special consideration in the exposure of women of reproductive age
  • Warning signs, restricted area, alarms, posting requirements
  • Basic protective measures–time, distance, shielding
  • Protective equipment–lead apron, lead gloves, thyroid shields, etc.
  • Basic radiation survey instrument use and limitations
  • Radiation monitoring programs and procedures
  • Relevant SOPs
  • Emergency procedures
  • Responsibilities of students, employees and TMCC
  • Applicable regulations
  • Radiation Safety Program
  • Interaction with RSO
  • Disposal
• Training records
  
  • Program directors are responsible to maintain training records of all X-ray users and have it available for reviews and inspections by the RSO and regulators.

Personnel and Area Monitoring (Dosimetry)

• Dosimetry is required for each adult employee who enters a controlled area who is likely to receive a dose in excess of 10 percent of the occupational exposure limits.
• Whole body dosimeters, extremity rings or area monitors may be issued to personnel using ionizing radiation devices and the areas where potential elevated radiation exposure levels may exist, as determined by the RSO, in order to demonstrate that exposures to personnel and public are kept ALARA.
• If dosimetry is required, employees shall be advised of reports of radiation exposure, which employees may request pursuant to the regulations to the program director or the RSO.

Shielding

• The X-ray device(s) shall be located or shielded according to regulatory requirements so that no radiation levels exist in any surrounding non-controlled area that could result in a dose to an individual present in excess of 2 mrem/hour or 100 mrem/year.
• The RSO may require the use of other special equipment or devices. This may include special shielding, alarms and warning devices, and other such apparatus.

Signs and Posting

• The following signs or labels, carrying the approved radiation symbol, shall be conspicuously posted as indicated. Warning signs are available from the RSO.
  
  • Caution X-rays or X-ray Equipment: at entry doors and on X-ray device(s).
  • Radiation Area: for accessible areas in which a major portion of the body could receive a dose in excess of 5 mrem/hour.
  • Caution: High Radiation Area: for accessible areas in which a major portion of the body could receive a dose in excess of 100 mrem/hour.
  • Notice to Employee (form NRC-1): must be posted by each X-ray unit.
  • SOP: be posted or available by each X-ray device.

Security and Storage

Each X-ray facility must assure security of X-ray device(s) and prevent an unauthorized access. This requires either constant surveillance of the equipment or locking of facility doors and devices.

All laboratory areas in which X-ray equipment are used shall have a sign displayed on all entrances as indicated above. Operating keys shall not be kept in the device when the device is not in active use.