放射性同位素使用规则

RULES FOR THE USE OF RADIOACTIVITY

You must be certified by EHS before you can use radioactivity. The guiding principle is COMMON SENSE. I take radioactive use seriously—ALL of the following guidelines MUST be followed, or I will get very upset!

1. We will primarily be using ³²P, ³⁵S, ¹²⁵I, ¹⁴C, and ³H. Please familiarize yourself with the properties of these compounds (half lives, ionization potential, etc.).

2. All ³²P source vials must be opened in the fume hood and behind a plexiglass shield. ALWAYS keep the proper waste container within 2 feet of your immediate work area.

3. Discard ³²P in a ³²P waste, and ³⁵S in a ³⁵S waste, etc. DO NOT mix isotopes, or else EHS will get upset.

4. Wear gloves when handling radioactive samples. Lab coats are recommended, but I don’t insist on their use.

5. A geiger counter should be ON (with sound preferably OFF) and within 2 feet of your work area. Please direct the probe of the counter AWAY from your work area.

6. Your work area should be covered with an absorbent pad. You may use your pipetmen for pipetting radioactivity, but always check the tip of your pipetman with a geiger counter after ejecting the tip to ensure that it is not contaminated. If it becomes contaminated, IMMEDIATELY wash the tip with warm water and soap. Any delays could result in long term contamination of your pipetman. Filter tips are useful to prevent contamination.

7. Eject tips directly into a radioactive waste container (which is never more than 2 feet away from you). (standard lab trash is periodically monitored for radioactivity, and 32P is easy to detect; this means that if radioactivity ends up there, there is a high likelihood that you will get caught!).

8. NEVER use the refrigerated microcentrifuge for spinning radioactive samples—this is a clean centrifuge. You may use the non-refrigerated centrifuge, but it should be monitored with a geiger counter AFTER EACH SPIN to ensure that there is no contamination. Contaminated surfaces must be cleaned IMMEDIATELY with warm water and soap, or else they will remain hot for months or years.

9. Discard all materials that have come in direct contact with radioactivty in the radioactive waste. When in doubt, check it with a geiger counter (which is never more than 2 feet away from you).

10. FREQUENTLY (every 3-5 min.) check your gloves with the (nearby) geiger counter to ensure they have not become contaminated. Contaminated gloves must be discarded in the (nearby) radioactive waste immediately to prevent cross-contamination of other surfaces.

11. Everyone is responsible for monitoring his/her own work areas after use of radioactivity. This should be done with a geiger counter with the SOUND ON.

12. ³²P “requires” shielding when working with this isotope, but keep in mind that this is particularly applicable to high dose (as from the source vial). Radiation emission falls off as the inverse square of the distance, which means that if someone is working with radioactivity nearby without shielding, you are NOT at significant risk. The other isotopes we use DO NOT require shielding.