||At biomedical research firms, controls and training minimize hazards in the laboratory.
Radioactivity is a time-tested tool of drug development. In genetic research, for example, radioactivity may be used to measure cellular functions such as DNA or protein synthesis. Scientists studying natural products use radioactivity to determine how a bacterial or fungal agent might produce a desirable compound, and oncology researchers can measure the cancer-fighting properties of an experimental compound by observing the amount of radiolabeled thymidine that tumor cells incorporate.
In chemical radiosynthesis laboratories, experimental compounds are formulated for purposes of animal testing. It is here that the largest amounts of radioactive materials used in the drug development process are routinely handled. These tagged compounds are produced for vital drug metabolism and pharmacokinetic studies in which the radioactivity acts as a signal revealing the distribution, concentration, and clearance of experimental compounds.
Pharmaceutical firms also use X-ray diffraction equipment to ascertain the purity of raw materials used to make drug products. The solid crystalline structure of intermediate and finished drug powders can be analyzed this way; however, an elemental analysis is obtained by X-ray fluoroscopy, a technique that produces real-time X-ray images. (This method also is used in veterinary medicine for angiocardiography and angiographic procedures.) Other devices, known as irradiators, are used to deliver high doses of penetrating gamma radiation to cell lines or experimental animals. The radiation can be used to partially suppress the immune systems of the animals for tumor-growth studies or, in the case of cell irradiation, to stop cell division for cloning purposes.
Getting the program
All uses of radioactive materials and radiation-producing devices require regulatory control that is overseen by a radiation safety officer (RSO), who works closely with biomedical researchers. The RSOs responsibilities include developing in-house rules that meet or exceed federal and state radiation safety regulations. These rules mandate compliance issues for the drug discovery scientists who handle radioactive materials. Failure to adhere to these rules can lead to unnecessary radiation exposures, safety infractions, and, possibly, disciplinary actions. Thus, it is important that scientists understand the rules and the mechanisms behind typical radiation safety programs.
The institutional use of radioactivity is controlled by the RSO and is governed by federal (U.S. Nuclear Regulatory Commission; NRC) and state regulations. The regulatory agencies grant licenses for radioactive materials that restrict the types and amounts of radioisotopes that may be stored at any one site. The licenses usually stipulate requirements for employee training, proper use of radiation-generating equipment, maintenance of a radioisotope inventory, and a radioactive-waste management program. It is the responsibility of the RSO to verify that the terms of the licenses are being met and that documentation intended to prove regulatory compliance is being maintained.
Because the RSO cannot look over the shoulder of every radiation user, in-house rules tend to be conservative. (These rules are spelled out in each companys radiation safety handbook.) Finally, the NRC or an equivalent state agency inspects radioactive materials licenses and compliance records through periodic on-site audits.
Through mandatory radiation safety training, the RSO must familiarize all radiation users with the in-house rules before they begin work. Currently, training is accomplished in many ways, including computer-based sessions that researchers can participate in at their convenience. Computer-based training is usually supplemented with lectures, quizzes, videos, and slide presentations. New radiation users are typically registered in a database and, once trained, they are allowed to begin the use of radioisotopes or radiation-generating equipment (often with a supervisor present during a brief probation period). Regulators also review evidence of this training, along with proof of annual continuing education, during their regular compliance audits.
Its all about control
If a one-word synonym could be used for radiation safety, it probably would be control. The RSO and radiation safety staff spend most of their time controlling the amounts and whereabouts of radioactive materials. Good radiation safety programs are designed to track radioactive compounds from the moment they enter a site to the time that they leave as waste products. In between, radiation safety staff seek out and minimize personnel exposures and laboratory contamination. On a daily or other periodic basis, the RSO typically
- reviews all purchase orders for radioactive materials,
- collects radioactive waste and documents isotopic amounts,
- acquires data to assess the current inventory of radioactive materials at a facility,
- performs laboratory safety surveys,
- orders the decontamination of contaminated equipment and laboratory surfaces,
- reviews all experiments involving radioactive materials to minimize internal and external radiation exposures,
- reviews the expertise and formal training of scientists who use radioactive materials, and
- updates databases of authorized users and authorized laboratories to facilitate safety training, radiation surveys, and laboratory audits.
Scientists who work with radioactive materials must adhere to certain requirements, all of which are monitored by the RSO. These requirements include
- wearing radiation dosimeters, safety glasses, lab coats, gloves, and possibly shoe covers when working around radioactivity;
- posting radioactive warning symbols on items and equipment as necessary;
- maintaining and reporting a written inventory of radioactive materials;
- packaging, tracking, and processing radioactive waste;
- performing and reporting periodic radioactive contamination surveys of the laboratory;
- issuing and retrieving radiation dosimeters;
- assisting with the assessment of human radioactive intakes (especially after predetermined exposure limits are breached) by submitting to bioassay methods such as thyroid scans and urinalyses; and
- designing experiments that avoid volatility, thereby circumventing or minimizing radioactive releases into the environment.
The RSO must maintain frequent communication with many people in an organization. In large research firms, the use of radioactivity may cut across several departments. The RSO usually does not have a direct supervisory or reporting line to the user such as the group leader or laboratory manager has with a junior researcher. Without such a direct means of accountability, the RSO depends on regulations and management-supported standard operating procedures to enforce compliance. Specifically, management must support the RSO to avoid legal liabilities associated with poor health and safety practices, poor public relations resulting from regulatory violations, monetary fines and/or the loss of radiation licenses, and increased scrutiny by radiation safety regulators.
Some kinds of licenses for radioactive materials specify the formation and periodic meeting of a radiation safety committee (RSC). A well-staffed RSC includes the RSO, safety and environmental experts, and other personnel who routinely work with and around radioactive sources. Besides providing a communication channel to the departments, the RSC offers scientific expertise and administrative assistance to the RSO.
Another communication conduit that the RSO uses is the radiation safety supervisor (RSS), who is assigned within each department or research group. This individual is responsible for communicating with the RSO on all radiation-related issues. For example, if a potential radioisotope user is brought on board, the RSS contacts the RSO to register the new researcher and set up the necessary safety training.
The need to know
Besides the above programmatic information, scientists using radiation or radioactivity need to know about a few items that are unique to the use of radiation and radioactive substances. These include the proper use and care of portable survey equipment (e.g., Geiger counters and beta/ gamma-scintillation meters), and liquid-scintillation counters (see box, Geiger and liquid-scintillation counters). Other fundamental radiation safety techniques that must be learned include proper contamination survey methods and radioactive spill control and decontamination protocols. When all the necessary skills are learned, scientists are properly trained, and a system of adequate management and oversight is put in place, working with and around radioactive sources can be a safe part of the drug development process.
To learn more about safety in a radiochemistry laboratory, see Todays Chemist At Work 2000, 9, 95100.
For information on radiation safety in an animal technology laboratory, see Lab Animal 2001, 30, 3542.
For technical information about radiation and radioactivity at a level appropriate for professionals in the field, see Shapiro, J. C. Radiation Protection: A Guide for Scientists and Physicians, 3rd ed.; Harvard University Press: Cambridge, MA, 1990.
Mark L. Maiello is an assistant radiation safety officer at Wyeth-Ayerst Research. Send your comments or questions regarding this article to email@example.com or the Editorial Office by fax at 202-776-8166 or by post at 1155 16th Street, NW; Washington, DC 20036.