Radiation safety is a concern in various settings. Nevertheless, in some instances, exposure is inevitable. Here’s a look into the OSL Technology and its medical and industrial uses.
Optically stimulated luminescence, or simply OSL, is the emitted luminescence from an exposed detector after being illuminated by stimulating light which indicates the level of radiation exposure. As such, it is a measuring process utilized to determine ionizing radiation doses.
OSL is mainly used in luminescence dating and radiation dosimetry. Luminescence dating refers to the method in determining the date duration of mineral grains exposure to sunlight or other sufficient heating sources.
On the other hand, radiation dosimetry measures the accumulated radiation dose on humans or built environments. For the former, these are health care workers and workers working on nuclear research wherein radiation dose accumulates on the tissue. The same applies to building materials with nuclear exposures for the latter.
Of course, radiation doses vary depending on the extent and severity of the exposure. Radiation doses can be absorbed dose (with potential biochemical changes in the tissue), equivalent dose (with expected biological damage), and effective dose (with potential long-term effects).
Personal doses are measured in the milli-Sievert unit (mSv).
When it comes to using the OSL badge, the Philippine Nuclear Research Institute (PNRI) recommends using such instead of the traditional film badges. Several industries are using OSL badges as a form of radiation protection.
Speaking of which, below are some of the medical and industrial uses of the OSL badge. But let’s define what an OSL badge is first.
OSL dosimeter or OSL badge is a solid-state device that measures ionizing radiation through the luminescence being emitted from the irradiated detector or OSL material. Upon reading, this detector will be illuminated by a stimulating light that causes the luminescence.
As such, the OSL badge is:
The OSL dosimeter uses aluminum oxide doped carbon and it is placed inside a moisture-proof packet. The packet has filters that can be used in determining the energy and radiation type.
When the OSL material is exposed to radiation, some electrons will be caught by the traps.
When the atoms in the sheet are radiation-exposed, the electrons are trapped in their excited state. During excitation, energy is released and gives off visible light. This is what’s actually measured to determine the radiation dose.
Ionizing radiation is a health hazard. Thus, facilities cannot emphasize enough the necessity of measuring, monitoring, and controlling doses within safe limits.
It pays to know if you have been exposed to radiation doses, so you would know what to do next. For instance, whether a facility-wide radiation dose reduction is needed can be determined by proper and timely monitoring.
The radiation type and dose can only be determined if the OSL badge is worn, with the front area facing the source of radiation. The goal is to use the badge on parts of the body that are most likely to receive exposure or where the highest exposure occurs.
The badge should be worn within the period prescribed. The dates that it should be worn are indicated in the badge itself before the wearer should turn it in for reading.
In the Philippines, OSL badge or dosimeters and TLD (thermoluminescent dosimeters) are commonly used. The workers can use the device in occupational settings where radiation monitoring is required.
Radiology-related jobs are at the highest risk. That’s why radiology technicians and technologists, for instance, must have an OSL badge as a form of personal protection. OSL badges have several purposes and uses as below.
In the medical setting, imaging is the primary reason for ionizing radiation exposure. This is especially true in the emergency department. Minimizing radiation exposure’s harmful effects through the proper detection and monitoring of cumulative doses of lifetime radiation is more than necessary.
Medically, an OSL badge is used in:
In the industrial setting,
Furthermore, it can also be used industrially, such as in:
In the Philippines and elsewhere in the world, the OSL badge can also be used in settings like waste spent sources, radiation sources transport, and educational establishments. Research, training, and service facilities are areas where the badge can also be of use.
Wearing an OSL badge is more than necessary if the workers are consistently exposed to:
This is true for medical, industrial, and other occupational settings.
All facilities or settings where an expected exposure to radiation dose is unavoidable require an OSL badge. Equally important to protecting the worker is protecting the immediate environment and the entire industry.
Speaking of worker protection, the OSL badge is mainly advocated for people working in facilities with low-radiation exposure. Pregnant workers, whose dose limit is only 500 mRem for the entire pregnancy duration, should also use the badge.
Based on the data provided by the Philippine Dose Registry of Occupational Exposed Workers or simply PhilDose, since 2012 when it started monitoring facilities, there are 1,867 facilities and 13,182 workers being monitored using OSL.
The top five facilities using the OSL badge in the Philippines overall are:
About 140 workers are identified as overexposed with the highest dosage of 487.60 Hp(10). Hp(10) refers to external whole body exposure at tissue depth 1cm.
The latest data is 2020 wherein PhilDose monitored 13 facilities, 83 workers, four of which are overexposed with the highest dose of 155.36 Hp(10). These four overexposures used OSL dosimeter type.
Nagase Philippines Corporation Group is one of the recognized personnel radiation dose monitoring service providers in the Philippines. The service entails determining the doses apparent in the facility prior to disseminating the use of the OSL badge. The service includes the rental of OSL badges to facilities and issuance of dose reports. The monitoring report also includes information on who should wear the badge, how, and for how long.