Safe Working Procedures in Nuclear Medicine

1. Facility Design and Worker Protection

The safety of work in nuclear medicine is not only dependent on protective clothing and equipment, but also on the overall design of the facility and the implementation of appropriate working procedures. These measures together aim to minimize external exposure, reduce the risk of contamination, and prevent the spread of contamination, thus optimizing the protection of workers.

Written local rules should always support work with unsealed radioactive sources, ensuring that safety protocols are clearly defined and followed at all times.

2. Minimizing Contamination Risk

To reduce the risk of contamination during the handling of radiopharmaceuticals, strict clean operation conditions and good laboratory practices should be adopted. Protective clothing should always be worn, and the work area should be kept tidy and free from unnecessary materials.

It is essential that the work area is:

• Monitored periodically for contamination.
• Cleaned frequently to ensure minimal contamination.

3. Restrictions in Controlled Areas

No food, drink, cosmetics, or smoking materials should be allowed in areas where unsealed radioactive substances are used. These items should not be stored in refrigerators designated for radioactive substances. Additionally, handkerchiefs and personal items should not be brought into these areas.

4. Proper Handling of Radioactive Materials

All manipulation involving the preparation, dispensing, and administration of radioactive materials should be conducted in a manner that minimizes contamination spread. Some key procedures include:

• Working over a drip tray covered with absorbent paper to catch any spills during the preparation and dispensing of radiopharmaceuticals.
• Using absorbent compresses during the administration of radioactive materials to further reduce the spread of contamination.
• Immediately covering any spills with absorbent material to prevent the material from spreading further. If the spill cannot be cleaned immediately, it must be clearly marked to warn others about its location.
• Initiating decontamination procedures as soon as possible after a spill.

5. Handling Contaminated Gloves and Protective Clothing

When wearing gloves that may be contaminated, avoid unnecessary contact with other objects. Once work with radioactive substances is finished, gloves should be removed and disposed of in a designated radioactive waste bin.

At the end of the workday, protective clothing should be removed and placed in an appropriate container for disposal. Hands should be washed thoroughly and monitored for contamination after the protective gear is removed.

6. Radiation Protection Principles: Time, Distance, and Shielding

The three fundamental principles for minimizing external radiation exposure are:

• Time: Minimize the duration of exposure. For example, in situations where high radiation exposure is anticipated, such as the preparation of radiopharmaceuticals, reducing exposure time is essential. However, this should not compromise the quality of work or other protective measures.
• Distance: Increase the distance between yourself and the radiation source. Direct handling of vials, syringes, or other sources that emit significant radiation should be avoided when possible. Forceps or tongs should be used to handle these materials, and properly designed vial and syringe shields should be employed.
• Shielding: Use shielding to reduce exposure. If handling unshielded radioactive materials or when exposure time is prolonged, work should be performed behind a properly designed lead glass shield or a similar protective barrier.

7. Managing Radioactive Waste

Radioactive waste should never be stored in the work area. It should be transferred to a designated radioactive waste storage room as soon as possible to prevent contamination of the work environment.

8. Patient Exposure and Safety

Patients undergoing nuclear medicine imaging studies are a source of radiation exposure and potential contamination. Contact with patients by nursing staff presents minimal hazard, as the radiation dose rate is relatively low. The accumulated dose to any single individual would not be significant. However, for nuclear medicine staff who spend a significant amount of time in close proximity to patients, the accumulated radiation dose can become considerable.

To minimize this exposure, workers should:

• Maximize their distance from the patient whenever possible.
• Limit the time spent in close proximity to the patient.

9. Summary of Protective Measures

The following protective measures can significantly reduce external radiation exposure:

• For preparation and dispensing of radiopharmaceuticals, work should be performed behind a lead glass bench shield, and shielded vials and syringes should be used whenever possible.
• For the administration of radiopharmaceuticals, lead aprons should be used for prolonged injections and high activity levels, and syringe shields should be used.
• During patient examinations, when the distance to the patient is short, a movable transparent shield should be used to reduce exposure.