Ionizing Radiation Policy

Complete Policy document in PDF format may be dowloaded here .

Specifically, a student must be aware of the following items:

Criteria for exposure

1. All radiographs shall be prescribed in writing on the Radiographic Request form or in axiUm and signed/digitally signed by a licensed dentist. The request must include clearly stated reason for the examination, prior to the procedure being done and entered in the Progress Notes sheet or in axiUm.

2. Radiographs for all patients shall be ordered only after clinical examination to determine the need and desirability of specific radiographs. Radiographs ordered merely on the basis of routine or for screening purposes shall not be permitted.

3. Radiographs shall be limited to the minimum number needed for a complete diagnostic work-up of the patient's dental need. The limits on exposure in each case will be determined by the professional judgment of a faculty dentist.

4. There can be no set frequency for radiographic examinations. The procedure to be employed and the frequency of the examination shall be determined by the professional judgment of the dentist ordering the radiographs.

5. If prior radiographs are available from a private dentist or another institution, they must be evaluated before new radiographs are prescribed. Only those additional views needed to complete diagnosis and treatment planning shall be exposed. This requirement does not preclude making a new complete intraoral survey if it is appropriate to the diagnosis.

6. Radiographs should not be used merely to document clinically apparent lesions.

7. Radiographs obtained for administrative purposes only, including those for insurance claims or legal proceedings, should not be made. However, diagnostic radiographs already made may be used for administrative purposes.

8. Demonstrations or training on X-ray equipment must be performed with proper protection of the observers and operator(s). Phantoms (mannequins), not humans, must be used for demonstration.

9. Deliberate exposure of an individual to radiographic procedure for training or demonstration purposes shall not be permitted, unless there is a diagnostic need for the exposure.

10. Individuals exposed for other than diagnostic reasons shall have the approval of the Human Use Subcommittee and All-University Radiation Protection Committee of the University of Minnesota.

11. Students should be assisted with all patients requiring three or more retake radiographs on a complete intraoral radiograph survey.

12. Patients should not be subjected to retakes to satisfy technical perfection. A minimally acceptable complete mouth radiographic survey should demonstrate, at least one time, each tooth in entirety and each interproximal space without overlapping and with clarity and accuracy.

13. Discretionary radiographic examination of patients who are known to be pregnant should be delayed until after delivery. Specific emergency radiographs may be obtained as needed.

14. No individual under 18 years of age shall be allowed to receive any occupational radiation dose except for training purposes.

Exposure Procedure

1. For film based radiography, only American National Standards Institute Speed Group E film or faster (i.e. Kodak Insight), shall be used for all intra-oral radiographic procedures.

2. For introral radiography, rectangular collimation should be achieved, either by using a rectangular tube or a rectangular collimation.

3. No operator shall be permitted to hold patients or films/sensors during exposure. If assistance is required for children or handicapped patients, an adult member of the patient's family may assist. The hands and body of the assisting person should be positioned in a manner to prevent primary beam exposure, and a protective lead apron and gloves of 0.5 mm lead equivalence should be provided for the assistant.

4. Only the patient shall be in the operatory during radiation exposure. All other individuals shall be required to leave the area.

5. During each exposure, the operator shall stand behind the barrier provided for each operatory.

6. Leaded rubber aprons and thyroid shields shall be used for all intra-oral procedures as an additional precaution to minimize scatter radiation exposure to the body of the patient.

7. Leaded rubber aprons should be used for all extra-oral procedures, when feasible.

8. The patient should be observed through a lead-glass window, if possible, during each exposure.

9. The patient record must accompany each patient before exposures can be made. The operator must review the history of previous patient exposure and status in regard to any infectious disease.

10. If a malfunction is detected in an X-ray machine, it should be corrected immediately or the machine shall be "closed down" until the necessary corrections have been made and the equipment recalibrated. All repairs/adjustments must be documented.

11. Mechanical support of the tube head and cone shall maintain the exposure position without drift or vibration. These shall not be hand held during exposure.

12. Intraoral film/sensor holding devices must be used except when endodontic procedures do not permit doing so. In those cases where the patient must hold the extraoral film cassette, the patient must wear 0.5 mm lead equivalent gloves on the hand that holds the cassette. In addition, any portion of the body, other than the area of interest must be covered by 0.5 mm lead equivalent material.

13. All intraoral film/sensor holding devices must be sterilized according to SOD Infection Control Policy.

14. Extra-oral exposures should employ screen-film combinations of the highest speed consistent with their diagnostic objectives. Direct exposure X-ray film (without intensifying screens in a cassette) shall not be permitted for extraoral radiography.

15. Intra-oral fluoroscopy shall not be used for intra-oral radiographic examinations.

16. The target to skin distance for intra-oral radiographs shall not be less than 7.1 inches, and preferably should be a minimum of 12 inches or longer. The target to skin distance for extra-oral radiography shall not be less than 11.8 inches.

17. The exposure control switch shall be of "dead-man" type, i.e., it requires continuous pressure by the operator to complete the circuit. This switch must be positioned behind a protective barrier.

18. All intra-oral X-ray machines shall be equipped with open-ended, shielded cones limiting the beam diameter to 2.76 inches at the patient's face. When using rectangular collimation, the longer side of the rectangular beam at the patient's face should not exceed 2 inches.

19. Extra-oral X-ray machines shall be collimated so that the beam size does not exceed the area of interest and/or the film cassette size.

20. The half-value layer (HVL, beam quality) for a given kVp should not be less than the values prescribed by the Minnesota Department of Health.

21. X-ray machines designed to use kilovotage of less than 50 shall not be used for diagnostic purposes.