Radioisotope fume hood

Hoods for Compliance with the Americans with Disabilities Act (ADA) Other Modes of Exhaust Perchloric Acid Hood Radioisotope Fume Hood Carcinogen Fume Hood Exhaust Ducts... 

Confine your work with radioisotopes to a small area in the laboratory. A convenient plan is to use a stainless steel tray lined with absorbent blotter paper coated on the bottom side with polyethylene. The paper must be replaced every day. If the radioactive matenals are volatile, the work should be done in a fume hood. If spills occur, a small work area such as a tray is much easier to clean than a large lab bench. If or other strong j8 emitter is used, it is necessary to work at all times with shielding between yourself and the radioactive samples. The most cost-effective and convenient shielding material is Plexiglas. The thicknesses of shielding required for various materials are given in Table 6.3. 

Stainless steel Stainless steel may be attacked by some chemicals but type 316 stainless or equivalent is commonly used for the lining of perchloric acid hoods. Type 304 stainless may be used for radioisotope hoods which need to be easily decontaminated. Because of its vulnerability to some chemicals and its relatively high cost, it is not recommended for general purpose fume hood use. Among the problem chemicals for stainless steel are acids and compounds containing haUdes. 

There are several different types of fume hoods (1) conventional hood, vertical sash, (2) conventional hood, horizontal sash, (3) bypass hood, (4) auxiliary air hood, (5) walk-in hood, and (6) self-contained hood. The differences in types 1,4, and 6 are especially important in terms of the amount of tempered air lost during operations, while 1,2, and 3 differ primarily in the airflow patterns through the sash openings. Figures 3.14 to 3.19 illustrate each of these types and the air currents through them during typical operations. In addition, there are specialty fume hoods for perchloric acid and radioisotopes, which will be treated separately. All of the hoods discussed in this section will be updraft units, where the exhaust portal is at the top of the hood, with of course, the exception of the self-contained type. 

Fume hoods used for radioactive matedals should be marked RADIOISOTOPE HOOD and in addition should be labeled with a CAUTION—RADIOACTIVE MATERIALS sign bearing the standard radiation symbol. The isotopes being used should be identified on the label. Under some circumstances, specialized additional signs may be needed. 

Do the hands-on work in a radiological fume hood for most radioisotope research, or in a glove box if the possibility of airborne exposure mandates it because of the type, the amount, or the form of the material. 

All chemicals are at least reagent grade and may be purchased from any convenient source. Carrier-free Na[ I] is obtained from ICN (Cat. No. 63034), but the equivalent radioisotope from any source is acceptable. Iodobeads are purchased from Pierce (Cat. No. 28665 G) and kept at 4°C. Solutions of protein and radioiodine are contained in 5-ml snap-cap polypropylene vials (Bio-Rad, Cat. No. 223-9820) and are transferred from one vial to another using 1.5-ml polypropylene transfer pipettes. These minimize the loss of protein due to adsorption to glass or other surfaces. Nitrocellulose (25 X 25-cm NC sheets with a 045- m pore size. Cat. No. 00850) is from Schleicher and Schuell. Washed iodobeads are blotted on Whatman No. 540 paper (Cat. No. 1540N321). Prepacked columns for desalting solutions of macromolecules are from Pierce (2- or 5-ml Excellulose gel columns. Cat. No. 20439 G or 20449 G, respectively) or Amersham (NAP 5 column. Cat. No. 17-0853-01). Any available gamma detector can be used to quantitate radioiodine. All operations are carried out at room temperature in a fume hood. 

Prior to working with radioactive materials, the scientist should attend a pertinent training course or consult a standard source of information on radioisotope methodology to become familiar with the precautions used in the safe handling of radiochemicals in the laboratory (e.g., DuPont, 1988a Shapiro, 1972 Stewart, 1981). As much as possible, experiments should be carried out, and plates with radioactive zones stored, in a fume hood. 

There are certain operations that require the use of more specially designed fume hoods incorporating certain features. The radioisotope hood and the perchloric acid fume hood are... 

Label all storage cabinets, refrigerators, fume hoods, glove boxes, or other areas used for storage or work with radioisotopes with the appropriate caution sign(s). 

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