What are radioisotopes?

Many of the chemical elements have a number of isotopes. The isotopes of an element have the same number of protons in their atoms (atomic number) but different masses due to different numbers of neutrons. In an atom in the neutral state, the number of external electrons also equals the atomic number. These electrons determine the chemistry of the atom. The atomic mass is the sum of the protons and neutrons. There are 82 stable elements and about 275 stable isotopes of these elements.

When a combination of neutrons and protons, which does not already exist in nature, is produced artificially, the atom will be unstable and is called a radioactive isotope or radioisotope. There are also a number of unstable natural isotopes arising from the decay of primordial uranium and thorium. Overall there are some 1800 radioisotopes.

At present there are up to 200 radioisotopes used on a regular basis, and most must be produced artificially.

Radioisotopes can be manufactured in several ways. The most common is by neutron activation in a nuclear reactor. This involves the capture of a neutron by the nucleus of an atom resulting in an excess of neutrons (neutron rich). Some radioisotopes are manufactured in a cyclotron in which protons are introduced to the nucleus resulting in a deficiency of neutrons (proton rich).

The nucleus of a radioisotope usually becomes stable by emitting an alpha and/or beta particle (or positron). These particles may be accompanied by the emission of energy in the form of electromagnetic radiation known as gamma rays. This process is known as radioactive decay.

Radioactive products which are used in medicine are referred to as radiopharmaceuticals.

-sources-

PRECAUTIONS FOR WORK PRACTICE WHEN USING RADIOACTIVE ISOTOPES

General Handling For Work With Radioisotopes

Preparation

• Clearly label containers, equipment, and areas for the handling of radioisotopes with radioactive labeling tape. The labeling tape can be obtained from your institution stockroom or through an appropriate vendor (link to our list of vendors). Minimize radioactive material work-space.
• Use absorbent material (benchcoat) and trays to confine spills and reduce the spread of potential contamination.
• Wear protective clothing. The minimum requirements include a laboratory coat, safety glasses and close-toed shoes. Wear disposable gloves, either single or double pair, depending on the radionuclide you are working with.
• Dedicate equipment such as pipettes and glassware to radioactivity work and avoid cross contamination.
  

Equipment / Supplies

• A Liquid Scintillation Counter for low energy beta radiation.
• Portable Survey Meter with appropriate probe(s).
• Disposable latex or plastic gloves.
• Lab coat, safety glasses, and close-toed shoes.
• Containers for radioactive waste.
• Pipettes dedicated to the use of your radionuclide.
• Safety glasses (to protect from splash and shield from beta radiation).

Work Practices

• Change your gloves often. Assume gloves are contaminated until proven otherwise. Do not leave the laboratory or touch things outside of the work space with potentially contaminated gloves. Remove gloves carefully from the inside out. Ensure that gloves are disposed of properly and wash hands immediately.
• Do not eat, drink, smoke, chew gum, or touch exposed areas of skin while working in a room where radioisotopes are handled. Be careful not to rub your eyes, scratch exposed areas of skin, or touch your hair when working with radioactive material.
• Use automatic or remote pipetting devices. NEVER pipette by mouth.

Contamination / Spill

• If skin contamination is detected, wash with mild soap and lukewarm water. Do not abrade the skin. If the contamination is not removed after two washings call the Radiation Protection Office.

Post-Work

• Promptly dispose of radioactive waste properly. Make a reasonable estimate of the amount of radioactivity in the waste and record on a radioactive waste tag.
• Lock-up and secure your radioactive stock solutions immediately after use.
• Survey yourself and work area for contamination with an appropriate survey meter. Decontaminate if necessary. Remove protective clothing and wash hands thoroughly with warm water and soap before leaving the laboratory.
• Participate in the bioassay program as requested by the Radiation Protection Office.

Important Precaution

Protection of Hands

Every precaution should be taken to avoid getting radioactive isotopes on the hands. The hands should be kept at a safe distance from sources because even small sources will cause burns. Wear rubber gloves or paper when handling radioactive materials. After working with radioactive materials, the hands should be washed thoroughly for two or three minutes using plenty of soap. A check of the hands should be made with a monitoring instrument after washing and the hands should be washed again if necessary.

Cleaning of Glassware

Care in the cleaning of glassware is necessary. All vessels should be marked after use and placed apart from other equipment so that it can be given special attention in cleaning. Even after cleaning, glassware should be kept separate from other equipment.

Special Laboratory Clothing

In a biological laboratory where routine work is done with radioactive materials, it is good practice to have special laboratory coats or coveralls, rubbers or special shoes, and even special trousers and shirts, which are kept for use in the laboratories only. Rubber gloves should be worn while handling active materials which may give rise to contamination of the hands.

REGULATION

Regulation Of Radioisotopes

In The United States

In the United States,The licensing and regulation of radioisotopes are shared by the NRC, the U.S. Environmental Protection Agency (EPA), and many State governments. The States regulate radioactive substances that occur naturally or are produced by machines, such as linear accelerators or cyclotrons.

The NRC is the Federal agency given the task of protecting public health and safety and the environment with regard to the safe use of nuclear materials. Among its many responsibilities, the NRC regulates medical, academic, and industrial uses of nuclear materials generated by or from a nuclear reactor. The NRC has relinquished its authority to regulate certain radioactive materials, including some radioisotopes, to most of the States. These States, which have entered into an agreement assuming this regulatory authority from the NRC, are called Agreement States.

The NRC maintains approximately 6,000 licenses for the use of radioactive materials, and the Agreement States maintain approximately 16,000materials licenses. Every license specifies the type, quantity, and location of radioactive material that may be possessed and used. Every licensee is inspected periodically either by the NRC or the Agreement State to ensure that radioactive materials are Being used and transported safely. Violators of regulatory requirements are subject to fines and other enforcement actions, including loss of license.

sources:

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

Office of Public Affairs

NUREG/BR-0217 Rev. 1 APRIL 2000

Regulation Of Radioisotopes

In The Malaysia

Malaysia, through the Atomic Energy Licensing Board (AELB) has adopted nearly 50 documents that provide guidelines, codes and standards concerning peaceful and safe nuclear activities. Issued by the International Atomic Energy Agency (IAEA), these safety related documents include the IAEA Code of Conduct on the Safety and Security of Radioactive Sources and the Code of Conduct on the Safety of Research Reactors.

These documents will be used by AELB in the implementation of national nuclear regulations and licensing requirements. In doing so, Malaysia has the moral advantage and sets the benchmark for the neighbouring countries to follow. In addition, Malaysia has also taken the initiatives to further improve the national infrastructure for monitoring aspects of safety, security and safeguarding the peaceful use of nuclear energy in the country. A National Radiological Emergency Centre for radiological emergency preparedness and response as well as a National Detection System will also be set up in the country.

The system monitors natural and released radioactivity and ensures the safety level in the environment. In addition, it also tracks any illicit trafficking activities of radioactive and nuclear sources to combat inappropriate use Of nuclear energy that threatens national and global security.

sources:

MOSTI

Ministry of Science, Technology

And Innovation Malaysia

Launch Issue / February 2008

NUCLEAR REGULATORY Newsletter