Med Pro Radiation Monitering

Differences Between Passive & Active Dosimetry

There are a number of fields of work in which the workers are exposed to radiation of one kind or another. At a hospital where they do x-rays and other radiation procedures, at a nuclear power facility where they are generating power, and when doing monitoring of different radiation sources such as radon. But some disasters happen that can cause exposure to a large number of people of radiation, such as Three Mile Island and Chernobyl. In all of these cases, monitoring the amount of radiation that people are exposed to is important, as getting large amounts of radiation can be very harmful. This is where dosimetry comes into play.

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What Is Dosimetry?

If you haven’t been able to guess by now, dosimetry is essentially the measurement, calculation, and assessment of the radiation dose absorbed by an object, and that object is typically the human body. Dosimetry as a discipline deals with both internal radioactivity as well as external radioactivity. For internal assessments, dosimetrists rely on a variety of monitoring, bio-assay, or radiation imaging techniques. For external assessments, dosimetrists rely on measurements with a dosimeter or by measurements made by other radiological protection instruments. As mentioned, dosimetry has a variety of applications for everyday positions as well as for catastrophes. By measuring the amount of radiation a person receives during a specific period of time, you can know if they will be receiving more radiation than they should, and you can appropriately limit the amount of exposure they have if they need to perform work in a radiation area.

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Where Is Dosimetry Needed?

Dosimetry is needed in a wide variety of jobs, probably more than you may be aware of. Even jobs where you wouldn’t think that you would be exposed to radiation can and should be measured. Some of these everyday positions include a diagnostic sonographer, microbiologist, chiropractor, and cell tower installer. All of these are exposed to different instruments that can give off radiation, either when those instruments are used or when they are in the presence of specific items. Most of these kinds of positions are exposed to small enough amounts and relatively infrequently, so they aren’t typically required to have measurements taken regularly. And then there are other professions such as a nuclear monitoring technician, nuclear medical doctor, and others that should be wearing at least passive, if not active, dosimetry measurement devices for monitoring. The latter positions need to be careful to limit the amount of radiation that they are exposed to regularly, as exposure beyond a certain level can lead to physical and health issues, either immediately or long-term.

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What Is Active Dosimetry?

If you happen to be in a job where you are required to have some sort of dosimetry device on your person, it could be either an active or a passive dosimetry device. When you are exposed to only low radiation levels, or only occasionally exposed to radiation, you will likely be using a passive dosimetry device. If you are working in a hazardous environment, such as a nuclear reactor or other places where you have a high chance at higher radiation levels, you will have an active dosimetry device. When operating, these devices continuously measure for the specific radiation type that your body is exposed to. They are designed to let the wearer know how much radiation they have been exposed to already, and are often equipped with a notification feature to let you know when you are approaching a pre-set limit of radiation exposure. Once you have been exposed to that level of radiation, it will let you know this as well. This kind of dosimetry device is beneficial when working in highly irradiated locations so that you do not get exposed to any more radiation than needed.

What Is Passive Dosimetry?

As you might guess, unlike the active dosimetry devices just discussed, there are passive dosimetry devices as well. While you might wonder why anyone would want to use a passive device, there are many instances where a passive device is preferrable. A passive dosimetry device is one that records the amount of radiation over time, but it is not analyzed in real-time. Instead, a passive dosimetry device is usually worn for a month, or even longer, when the person is on-duty. After each period (month, quarter, etc.), a new passive dosimetry device is used, and the old one is collected to be analyzed. These kinds of passive devices are often used in hospitals and other places where some personnel are exposed to low levels of radiation on a periodic basis. Because it is known that the radiation levels will be low, these passive devices are preferred, and they give an easy way to track radiation exposure in a department among the workers. The business can also use this for various record-keeping needs, as well as for insurance purposes to ensure that they are not overexposing workers, etc.

Where Each Can Be Used?

Whether it is a passive dosimetry device or an active dosimetry device, each has its application depending on what the job is. As mentioned, hospitals are an obvious place where some workers will be exposed to radiation, either from administering certain procedures with patients or different machines in operation that produce radiation. Because nations have set specific limits on the amount of radiation a person can be exposed to during a calendar year, it is necessary to monitor these personnel with a passive device, usually a worn tag during their shifts. Another profession that uses passive monitoring devices is in the mining industry. Radon can be detected, but it can’t always be mitigated to prevent exposure. As such, miners would wear these passive dosimetry devices to monitor the miners and ensure they aren’t overexposed during their shifts. Active dosimetry devices are a must when working in an area with high radiation levels, such as from a nuclear accident.

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Wrap Up

Every day we are exposed to a certain level of radiation from the sun and other sources. This isn’t anything to be concerned about, but if you work in certain professions, including in the medical field, military, or nuclear power field, you will want to be able to monitor your exposure over time. Unknown exposure to high levels of radiation can have long-term effects, and there are limits in place to ensure that people aren’t exposed to any more radiation than necessary (beyond what they would normally receive). Utilizing either a passive or active dosimeter will help to ensure that you aren’t exposed to radiation levels beyond where you should be. While radiation can be scary, the fact is that we are exposed to radiation every day just living our life. Only if you were going into a nuclear power facility that had experienced a serious meltdown should you be concerned with elevated radiation levels. All other radiation exposure that you will have in your job is very minor, and these monitoring devices help ensure that there are no additional exposures going on.

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