Instant Exposure Information Now Available For Radiation Workers
We tend to think of New Zealand as nuclear-free but the reality is quite different. Radioactive material produced in
nuclear reactors in other parts of the world is imported into the country on a near daily basis and thousands of x-ray
generations are at work up and down the country. X-rays, gamma rays and radiopharmaceuticals are used extensively in
human and animal health and radioactive sources are deployed in a plethora of industrial and research applications.
Human senses cannot detect the presence of ionising radiation and over time the cumulative effects of undetected
radiation exposure become a threat to health. This is of particular significance for the thousands of workers whose
occupation brings them into close and frequent contact with sources of ionising radiation. New Zealand has regulations
setting occupational exposure limits for radiation workers and personal monitoring is generally mandatory to ensure that
these limits aren't exceeded.
At present most radiation workers in New Zealand are monitored using a piece of photographic film worn inside a plastic
holder. After a wearing period of between one and three months, the film is removed from the holder and sent away to be
developed and a dose estimated by measuring the change in density (or blackening) of the processed film. Practical
film-badge dosimeter technology emerged from the Manhattan Project during the Second World War.
The way in which radiation workers are monitored is set to change with the introduction of a new and very different type
of dosimeter that has just been approved for legal use in New Zealand. This device is based on novel direct ion storage
technology where a specially fabricated transistor records the total amount of ionizing radiation received. Direct ion
storage technology is used at the European Organisation for Nuclear Research (CERN) facility in Switzerland and a
militarised version is used by a number of European NATO member countries.
The radiation sensitive components of the new dosimeter are packaged together with interface circuitry into a small and
lightweight USB pen-drive shaped unit. Instead of waiting months for information about a possible exposure, radiation
workers can now plug their dosimeter directly into a USB port of an Internet-connected Windows or Mac computer and get
an instant readout of any dose received. Dosimeters can be read on-site as often as needed offering peace of mind and
saving time and hassle sending dosimeters away for processing. Incident exposures can be investigated immediately
minimising further potential harm.
Based in Christchurch, Radiation Protection Services Limited (RadPro) provides personal monitoring solutions for
individuals at risk of occupational exposure to sources of ionising radiation. RadPro is an authorised distributor of
Mirion Technologies Dosimetry Services Division and distributes the instadose direct ion storage dosimeter in New