Complete Dosimetry Program Management Guide: Setup, Compliance & Cost Optimization

Providing dosimetry solutions is our business, so we wanted to share the intricacies of dosimetry with you. Whether you're new to radiation monitoring, or you're a seasoned veteran, we believe this article will serve as your one-stop shop for all things dosimetry.

We hope you find this article informative, and as always, we look forward to hearing your feedback!

What Is Dosimetry?

Dosimetry (also known as radiation dosimetry) is the accurate and systematic measurement, calculation, and assessment of the ionizing radiation dose absorbed by matter or tissue. Ionizing radiation is high-energy radiation. This includes x-ray, beta, gamma and neutron radiation, capable of producing ionization in the substances it passes through.

Emitted Radiation: What Does It Mean?

When we talk about "emitted radiation," we're referring to the energy released from atoms as they transition from an unstable (radioactive) state to a more stable one. This energy is sent out in the form of particles or electromagnetic waves. Common examples include the beams produced during X-ray procedures, as well as the gamma rays and beta particles released by radioactive materials.

While you may encounter the Roentgen as a traditional unit for measuring how much X-ray or gamma radiation is present in the air, this measure doesn’t provide information about the effects of that radiation on living tissues. That’s where dosimetry steps in – it goes beyond just exposure, focusing on understanding the actual energy deposited within our bodies.

In this case, we are talking about the energy deposited from the radiation in human tissue.

Gamma Rays: Characteristics and Risks

Gamma rays are an energetic form of electromagnetic radiation, much like X-rays, but with distinct differences that set them apart.

Where do gamma rays come from? Unlike X-rays, which are generated from interactions in the electron shells of atoms, gamma rays originate directly from an atom’s nucleus, typically during radioactive decay. These rays pack significantly more energy, which gives them remarkable penetrating ability; they can pass through dense materials, including the human body and thick layers of shielding, with surprising ease.

This penetrating power is both a blessing and a concern. Gamma rays are invaluable in fields like cancer therapy, industrial imaging, and sterilization, but their energy also means they can interact with living tissue on a cellular level. Unprotected or accidental exposure can damage DNA and other critical cellular components, increasing the risk of acute radiation sickness or, over time, certain cancers.

Interestingly, gamma rays aren’t limited to man-made sources such as medical equipment and industrial meters. They’re also unleashed naturally from cosmic sources. For example, bursts from solar flares or distant cosmic events can emit gamma radiation, sometimes even disrupting electronics here on Earth, a key challenge for organizations like NASA and researchers who track cosmic weather.

In summary, gamma rays are both powerful tools and significant hazards. Their origins in nuclear processes and unmatched penetrative strength demand that we understand their risks and apply rigorous safety measures whenever they are present.

X-Rays: Characteristics and Potential Risks

X-rays are one of the most familiar types of ionizing radiation, particularly known for their pivotal role in medical imaging and diagnostics. As a form of electromagnetic radiation, X-rays can penetrate various materials, including human tissue, making them invaluable in healthcare settings for revealing bones and internal structures.

When you receive an X-ray at your dentist’s office or during a medical checkup, the X-ray beams pass through your body and are captured on film or digital sensors, unless shielded by protective gear like lead aprons. This property – passing through soft tissue but being absorbed by denser substances like bone – is exactly what makes them so useful for diagnostic purposes.

However, exposure to X-rays isn’t limited to the doctor’s office. There are also natural sources. For example, the sun emits X-rays, but our atmosphere does an excellent job of shielding us. People who spend a great deal of time at higher altitudes, such as frequent flyers or airline crew, receive a bit more exposure, though it remains a small fraction compared to occupational limits.

As beneficial as X-rays are, it’s important to remember that, like all forms of ionizing radiation, they can pose risks at higher exposures. Prolonged or repeated exposure without proper precautions can potentially cause cellular damage, which is why strict safety protocols (especially in medical or industrial environments) are always followed. For most people, occasional medical X-rays pose extremely low risks, but minimizing unnecessary exposure remains a cornerstone of best practices in radiation safety.

Alpha Radiation: Characteristics and Associated Risks

Alpha radiation, comprised of alpha particles (often symbolized as α), originates from certain naturally occurring radioactive elements such as radium, radon, and uranium. These particles are relatively heavy and carry a positive charge, making them energetic but also quite limited in their ability to travel or penetrate materials.

In fact, something as thin as a single sheet of paper, or even the outer layer of our skin, is sufficient to stop alpha particles in their tracks. This means external exposure to alpha radiation usually isn’t cause for concern.

However, the real issue arises if an alpha-emitting substance enters the body. This can happen if radioactive dust or gas is inhaled, swallowed, or enters through a cut or abrasion. Inside the body, alpha particles can cause significant damage to living tissues and cells due to their high ionizing power concentrated over a very short range.

A real-world example includes radon gas, a common alpha emitter, which can seep into homes from soil, rock, or groundwater. Prolonged exposure to radon, especially in enclosed spaces, is a known health risk and one of the reasons indoor radon testing has become routine in many regions.

Internal vs. External Radiation Exposure

Humans can be exposed to radiation in two broad ways: internally and externally.

Internal Exposure

Internal radiation exposure can occur through several pathways:

• Ingestion: Eating or drinking contaminated substances.
• Inhalation: Breathing in radioactive airborne particles.
• Absorption: Skin absorption through direct contact with radioactive particles or liquids.
• Wounds: Entrance of radioactive materials through cuts or abrasions.
• Injection: Introduction of radioactive material directly into the body.

External Exposure

External radiation exposure happens when all or part of the body is exposed to penetrating radiation from an outside source. This may come from:

• Cosmic radiation from space
• Naturally occurring radioactive materials in building materials, soil, or the environment
• Occupational or medical sources, such as those present in healthcare, research, or industrial settings
• Everyday background radiation that is always present in the environment
• Medical imaging procedures, like X-rays

Internal Dosimetry vs. External Dosimetry

Internal dosimetry assessment relies on various monitoring, bioassay, and/or radiation detector counting techniques. External dosimetry is based on measurements with a dosimeter or inferred from measurements made by other radiological protection instruments.

Internal dosimetry comes into play when radioactive material is taken into the body, whether through inhalation, ingestion, absorption, or entry via wounds or medical procedures. In these situations, specialists must determine the committed effective dose equivalent (CEDE) to understand the level of exposure over time. This process is crucial for accurately assessing health risks, especially for individuals working in environments where internal contamination is possible, such as medical, research, or nuclear power settings.

External dosimetry is based on measurements with a dosimeter or inferred from measurements made by other radiological protection instruments.

Types of Dosimeters by Technology and Functionality

When it comes to monitoring radiation exposure, dosimeters come in a variety of forms, each leveraging different technologies and functional features to suit diverse environments and needs.

• Passive dosimeters: These devices, such as thermoluminescent dosimeters (TLDs) and film badges, are worn throughout the monitoring period. They collect data without providing a real-time reading, and must be processed in a laboratory to determine exposure levels once the monitoring period has ended.
• Electronic dosimeters: Offering real-time digital readings, electronic personal dosimeters (EPDs) are especially useful in situations where immediate dose information is required. They often include audible and visual alarms to notify wearers if a preset radiation threshold is exceeded. NetDose™, a semi-passive digital dosimeter, accumulates radiation exposure data over time and uses active electronic components for cumulative data storage with easier, more immediate retrieval.
• Pocket dosimeters: Compact and portable, these devices – like quartz fiber or digital pocket dosimeters – are designed for immediate, on-the-go monitoring. Some display dose information instantaneously, making them a practical choice for workers who need to move in and out of monitored zones frequently.
• Active area monitors: Unlike personal dosimeters, area monitors continuously assess and display ambient radiation levels in a specific location. They can be set up permanently or temporarily and provide ongoing readings for workplace safety.

Each type offers distinct advantages, ranging from basic dose tracking to sophisticated, real-time monitoring, allowing organizations to tailor their radiation safety programs to their unique operational requirements.

Which Industries Face the Highest Occupational Radiation Risks?

Some professions encounter ionizing radiation far more frequently than others, making monitoring and dosimetry especially important in these fields. Industries where workers are routinely exposed to higher levels of radiation include:

• Healthcare: Radiologists, nuclear medicine technologists, veterinary staff, and dental staff who operate X-ray machines or use radioactive tracers are regularly monitored for exposure.
• Aviation and Air Transportation: Airline pilots and flight crews spend substantial time at high altitudes, where background cosmic radiation is significantly higher.
• Non-Destructive Testing: Individuals inspecting materials using radiographic equipment often work in environments where radiation is present as part of daily operations.
• Nuclear Power and Energy Production: Plant operators, maintenance personnel, and engineers are exposed to both routine and incident-related sources of radiation.
• Military and Defense: Certain roles involve exposure to radiation sources, such as those working with radar, nuclear propulsion, or defense-related radiological materials.
• Research Laboratories and Universities: Scientists and lab technicians handling isotopes or operating accelerators require careful monitoring.
• Industrial Radiography and Manufacturing: Inspectors and machine operators working with industrial radiographic sources or materials embedded with naturally occurring radioactive materials (NORM).

In each industry, ensuring accurate measurement and compliance with regulatory dose limits is critical for employee well-being and safety standards.

The ALARA Principle: Minimizing Radiation Exposure

To further ensure safety when working with ionizing radiation, the ALARA principle comes into play. ALARA stands for "As Low As Reasonably Achievable," and it's exactly what it sounds like: a set of best practices designed to keep radiation exposure to a minimum.

There are three core strategies to follow under ALARA:

• Time: Limit the amount of time spent near a radiation source. Less time means less exposure.
• Distance: Whenever possible, increase your distance from the source. The farther away you are, the lower the dose.
• Shielding: Place appropriate shielding materials, like lead or concrete, between yourself and the radiation source to absorb or block some of the energy.

Radiation workers can significantly reduce their occupational dose by consistently applying these principles. And of course, wearing a dosimeter further ensures that exposures stay within recommended safety limits by providing an ongoing record of the dose received.

Neutron Radiation: Unique Properties and Potential Hazards

Neutron radiation stands out as a particularly potent form of ionizing radiation, distinguished by its ability to penetrate deeply into most materials, including human tissue, more effectively than many other types of radiation. Unlike alpha or beta particles, neutrons don’t carry an electric charge, which means they can travel through dense substances, and shielding is often more challenging.

A distinctive aspect of neutron radiation is its potential to make other materials radioactive through a process called “neutron activation.” This transforms stable substances into radioactive ones, presenting additional ongoing risks even after the initial exposure.

You’ll most commonly encounter neutron radiation in environments like nuclear reactors or during certain particle accelerator operations. Thankfully, rigorous shielding (often layers of water, concrete, or specialized plastics) minimizes exposure in controlled settings. Perhaps the most dramatic example of neutron radiation occurs during the detonation of nuclear weapons.

Exposure to neutron radiation can cause significant biological harm if not carefully managed, underscoring the importance of regular monitoring and robust protection measures for anyone working in or around affected environments.

Beta Radiation: Characteristics and Potential Risks

Beta radiation, made up of energetic beta particles (β), is stronger and more able to penetrate materials than alpha radiation. Unlike alpha particles, beta particles can pass through the outer layer of human skin. While this means they can cause skin injuries such as burns, they typically won't reach internal organs unless inhaled or swallowed.

Protective Measures

Standard safety practices include the use of:

• Barrier clothing like rubber gloves and lab coats
• HEPA respirators
• Lead aprons when appropriate

These precautions significantly reduce exposure risk during occupational or medical use of beta-emitting sources.

Sources and Everyday Examples

Several isotopes, including those of carbon, strontium, and phosphorus, emit beta radiation. In healthcare, beta radiation plays a role in specific cancer therapies. In other settings, beta radiation is used for precision, such as testing the thickness of materials like paper (think about the quality control processes at a paper mill).

Remember: just like alpha radiation, beta particles pose the most significant risk if beta-emitting materials are ingested or inhaled. Proper handling, personal protective equipment, and monitoring are essential for anyone working with beta-emitters.

Types of Radiation Dosimeters Offered By RDC

Radiation Detection Company is dedicated to keeping you and all your employees safe. We have over 75 years of experience providing quality dosimetry service to over 40,000 companies nationwide.

RDC offers a wide range of affordable and comprehensive radiation badge services to accommodate the needs of any organization, big or small. We also recognize that choosing a solution can be intimidating. If you need help understanding your dosimetry needs, please contact our world-class customer service team. They will be happy to provide guidance.

OSL Whole Body:

Our standard OSL badge (or Type 84 badge for photon monitoring) is a 2-element beryllium oxide (BeO) badge with a minimum reportable dose of 10 mrem (0.10 mSv), and a LLD of 1 mrem. These badges are used to monitor occupational exposure to a single individual working with radioactive materials to ensure the dose received remains within the allowable Dose Limits. The BeO OSL dosimeter is optimal for medical practitioners and technologists, including veterinarians, dentists, chiropractors, employees working in mammography and fluoroscopy, or any practice with potential exposure to photons.

TLD Whole Body:

In reference to external radiation exposures, “whole body” is considered to be the head, torso, arms above the elbow, or legs above the knee.

The TLD-XBG is a four-element radiation badge with a minimal reportable dose of 10 mrem (0.10 mSv) and a lower limit of detection of 1 mrem (0.010 mSv). These badges are used to monitor occupational exposure to a single individual working with radioactive materials to ensure that the whole-body dose received remains within the allowable dose limit.

Ring Badge:

Our XTLD-XBG extremity is a single-element ring dosimeter for extremities. The ring badge is optimal for radiation workers whose job functions potentially require their fingers, hands, arms, toes, feet, or legs likely to receive radiation exposure above established monitoring requirements. The XTLD-XBG is a one-element radiation detector with a minimal reportable dose of 10 mrem (0.10 mSv) and a lower limit of detection of 5 mrem (0.05 mSv). These employees may benefit from a ring badge to ensure the extremity dose received remains within the allowable dose limit. 

Wrist Badge:

Our TLD-XBGN is a four-element dosimeter badge with a minimal reportable dose of 10 mrem (0.10 mSv) and a LLD of 1 mrem (0.010 mSv). The badge is fitted with a Velcro strap to be worn around the wrist. The wrist badge is ideal for radiation workers whose arms may receive a higher exposure if dexterity is a concern. The wrist badge helps ensure the extremity dose received remains within the allowable dose limit.

Fetal Monitoring:

Fetal monitors are available for radiation workers who are pregnant to ensure that the fetus does not exceed a significant radiation dose of 500 mrem for the entire gestational period or 50 mrem per month. The badge should be worn on the abdomen to provide the best estimate of the dose to the embryo/fetus.

Area TLD:

Area monitors can be used to ensure that the public is not being exposed to more than 100 mrem/year from outside a room/building. In addition, they can monitor occupational dose to employees in a room where the source is located or a room near a source that radiation could potentially reach.

Measuring Radiation Dose

The U.S. Nuclear Regulatory Commission (NRC) has established dose limits for occupational exposure for people working with radioactive materials or ionizing radiation (such as x-ray imaging equipment) and external beam radiation therapy. The dose limit functions as a form of radiation protection for personnel monitoring. Radiation dose is often reported in rads, and the dose equivalent is recorded in rems. If you or your staff are working with such materials or equipment, these regulations apply and must be followed.

There are several ways to measure absorbed doses from ionizing radiation. People in contact with radioactive substances in the course of their employment – or people who may be exposed to radiation – normally carry personal dosimeters. These dosimeters are specifically designed to record and indicate the radiation dose received.

Personal dosimetry works by constantly tracking radiation exposure to determine how much radiation an individual has accumulated over time. By wearing a dosimeter throughout their workday, personnel can ensure that their exposure stays within regulatory limits, providing an ongoing record for both safety and compliance.

In the past, personal dosimeters were generally devices fastened to the external clothing of the person being monitored. The devices contained photographic film, and these instruments were known as film badge dosimeters.

Today, the film badges of the past have been largely replaced by devices such as the TLD badge, which uses thermoluminescent dosimetry. This shift in technology allows for more accurate, reliable, and sensitive monitoring, ensuring that radiation workers are better protected and that exposures can be promptly addressed if they approach regulatory thresholds.

What Are the Three Types of Dose in Radiological Protection?

Absorbed Dose

The measure of the radiation energy deposited in matter by ionizing radiation per unit mass. Absorbed dose is a measurable quantity and a key component of radiation protection as well as radiology.

Effective Dose

A crucial piece of radiological protection, effective dose is a calculation that sums up all of the different exposures into a single measure that generally reflects the overall risk for the whole body.

The sum of the products of the dose equivalent to the organ or tissue (HT) and the weighting factors (WT) applicable to each of the body organs or tissues that are irradiated (HE = ΣWTHT).

Dose Equivalent

A measure of the biological damage to living tissue as a result of radiation exposure. Also known as the " biological dose," the dose equivalent is calculated as the product of absorbed dose in tissue multiplied by a quality factor and then sometimes multiplied by other necessary modifying factors at the location of interest. 

In practical terms, assessing dose equivalent involves determining how different types of ionizing radiation impact the body. The process begins with identifying the type of radiation a person has been exposed to and assigning a quality factor (Q) specific to that radiation. This quality factor accounts for the varying biological effectiveness of different radiation types, such as alpha, beta, gamma, or neutron radiation.

By multiplying the absorbed dose (measured in grays or RADs) by the quality factor, we arrive at the dose equivalent, which is expressed in units of rem (Roentgen Equivalent in Man) or sievert (Sv). This value reflects the potential biological risk or effectiveness of the radiation exposure, providing a more meaningful measure for evaluating possible health effects compared to absorbed dose alone.

Background Radiation and The Role of The Control Dosimeter

Background radiation is a measure of the level of ionizing radiation present in the environment at a particular site. Which this occurs naturally and is not due to deliberate introduction of a radiation source. A Control Dosimeter is a badge that is fundamentally the same as the radiation badge used to protect radiation workers. However, Control Dosimeters are used to measure external radiation exposure from non-occupational radiation sources. (while the badge worn everyday measures occupational exposure and background radiation). Subtracting from the dosimeter worn by the worker yields the occupational dose.

Measuring Occupational Dose

Occupational dose is the amount of ionizing radiation exposure (which includes gamma rays) received by workers in the course of their employment. A control dosimeter measures the background radiation dose received during shipment (either to you or back to us) and storage. To obtain occupational dose, the measurement recorded on the control dosimeter is subtracted from the individual doses recorded on each badge in the group.

How to Maintain a Compliant and Effective Dosimetry Program

Maintaining a compliant dosimetry program is crucial for all businesses that use radiation in their operations. A dosimetry program helps ensure that levels of occupational dose are kept within safe limits. This in turn helps to protect your employees from the potential health risks associated with radiation exposure.

It's extremely important that your dosimetry program is reliable and accurate. Your employees need to understand its function and they are properly trained. Businesses that don’t comply with dosimetry requirements face a number of implications that can negatively impact the success of the company and regulatory compliance.

Here are four tips to maintain a compliant dosimetry program:

1. Maintain a reliable dosimetry vendor that can meet your exchange requirements.
2. Appoint a radiation safety officer.
3. Use a badge board system to track dosimeters.
4. Keep a spare dosimeter for new employees.

For more tips, check out this blog post: 5 Challenges Companies Face When Out Of Compliance With Their Dosimetry Program.

Take The Next Step!

Want to learn more about RDC’s dosimetry badge solutions? Please visit our Solutions page to view our full suite of offerings. Have a question that we did not address in this article? Please reach out to our Customer Care team, and one of our specialists will be happy to assist you.

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