Medical physics has been an integral part of medicine and healthcare over the greater part of the last century. Applying physics theory, concepts, and methods, scientists have created patient imaging, measurement, and treatment techniques that revolutionized the medical world. One product of medical physics has been the evolving specialty called radiopharmaceutical dosimetry, the calculation of absorbed dose and optimization of radiation dose delivery in cancer treatment. Today, we address internal dosimetry, the subset of medical physics that aims to optimize treatment and protect the patient from any undesirable side effects.
What is internal dosimetry?
Dosimetry is the measurement of radiation energy imparted to body organs and tissues. Radionuclides emit beneficial ionizing radiation that is useful for both diagnostic imaging of various diseases as well as for cancer treatment. Thus, medical internal dosimetry is the assessment of internal radiation dose from incorporated radionuclides associated with such life-saving radiopharmaceuticals.1 Radiation dose is the amount of energy imparted by radiations emitted during disintegration of radioactive atoms that constitute part of the radiopharmaceutical chemistry. Dose to organs of the body is quantified per unit mass (or weight) irradiated tissue. Dosimetry provides the fundamental quantities needed for several important purposes, including record-keeping, radiation protection decision-making, risk assessment, and cancer-treatment planning.2 The purpose and objective is to optimize medical benefit while minimizing potential radiation damage to body cells, tissues, and organs.
Dosimetry is a complex physical and biological science. Internal dosimetry provides critical information needed to better understand the biological mechanisms governing radionuclide uptake, translocation, and excretion from the body. The radiation dose imparted depends on the type, amount, and distribution of radionuclides, as well as specific nuclear properties, such as energy emitted.
Internal dosimetry differs from “external” dosimetry, which deals with the radiation dose from sources outside the body. Devices such as dosimeters measure external dosimetry directly, while internal dosimetry relies on indirect methods of radioactivity inside the patient using bioassay and imaging measurements.3 Bioassay is the measurement of the activity or concentration of radionuclides in biological samples. Samples can include urine specimens, feces, blood, or breath. Imaging techniques, such as whole-body counters or gamma cameras, can detect the radiation emitted by the radionuclides inside the body. This helps to provide information on their location and quantity.1
When is internal dosimetry used in healthcare?
Internal dosimetry mainly benefits patients who receive radionuclide therapy, a treatment that involves administering radioactively labeled proteins, such as monoclonal antibodies, to target specific types of cancer.3 It also helps to evaluate and account for unique patient variations in biodistribution—the way that different subjects respond to treatment. Internal dose assessments analyze radionuclide behavior in both normal (healthy) organs, as well as tumors. For example, imaging measurements provide physicists with important information to determine tumor uptake, retention, and clearance. In doing so, administered activity can be tailored according to patient health status, age, size, sex, and basal metabolic rates.
How does internal dosimetry produce useful data?
The main challenge of internal dosimetry is to track and follow the uptake, redistribution, metabolism, and clearance of the administered radiopharmaceutical inside the body over extended time periods after administration.4 Tracking sometimes involves mathematical modeling to describe the absorption, distribution, metabolization, and excretion of radionuclides by the body. Biokinetic models may be developed from the study of population groups, knowledge of radionuclide behavior in different organs, and the unique chemistry of each radiopharmaceutical. Biokinetic models incorporate mathematical compartments representing a particular organ or a tissue, and descriptions of the transfer rates that reflect the movement of radionuclides from one body compartment to another.1
Summary
Internal dosimetry is an important tool for radiation protection, especially in the fields of nuclear medicine, occupational health, and environmental monitoring. Dosimetry helps to customize or personalize nuclear medicine in cancer patients. In a broader sense, internal dosimetry is also applied to occupational and environmental health to prevent or reduce the exposure to radionuclides, by providing information on the sources, pathways, and levels of intake, and by suggesting appropriate measures, such as respiratory protection, contamination control, or dose limits. Internal dosimetry can also help to verify the adequacy of workplace controls, to demonstrate regulatory compliance, and to provide medical and legal evidence in case of accidental or intentional exposure.
Special software tools have been developed for the clinical nuclear medicine setting to facilitate medical imaging and calculate internal doses.
QDOSE® Multi-purpose Voxel Dosimetry (Personalized Dosimetry in Molecular Radiotherapy) is a complete, one-stop solution software for all internal dosimetry needs with multiple parallel workflows. With USFDA 510(k) clearance granted in August 2023, QDOSE® has proven its quality and compliance. To learn more, visit our QDOSE® webpage or schedule a meeting with our team.
Sources
Sudprasert W, Belyakov OV, Tashiro S. Biological and internal dosimetry for radiation medicine: current status and future perspectives. J Radiat Res. 2022;63(2):247-254. doi:10.1093/jrr/rrab119
Bartlett R, Bolch W, Brill AB, et al. MIRD Primer 2022: A Complete Guide to Radiopharmaceutical Dosimetry. Society of Nuclear Medicine & Molecular Imaging; 2022.
What is Internal Dosimetry – Definition. Radiation Dosimetry. Published December 14, 2019. Accessed November 16, 2023. https://www.radiation-dosimetry.org/what-is-internal-dosimetry-definition/
Patient safety is a major focus of radiation treatments and diagnostic imaging procedures. However, radiation workers in the healthcare field are also at risk for exposure to unsafe amounts of radiation—primarily scatter radiation—due to the nature of their work.
Protecting healthcare workers from scatter radiation is an important part of a successful radiation safety program. In today’s blog post, we discuss what scatter radiation is, effects on the human body, and four ways to help limit occupational exposures.
What is scatter radiation?
During typical diagnostic imaging procedures such as fluoroscopy, CT, or mammography exams, healthcare workers are exposed to scatter radiation.
Scatter radiation is a type of secondary radiation.1 It occurs when the primary beam from a source such as a CT Scanner, X-Ray, or Fluoroscopy unit interacts with matter. For scatter radiation, the “matter” that X-ray beams are most often interacting with is the patient in a procedure. As the primary beam intercepts the patient’s body tissues, some X-rays will bounce off those atoms to create secondary, specifically scatter, radiation.
Scatter radiation can be moderated through some machine positioning, like the C-Arm. The primary beam for a C-Arm is sent up through the table into a patient before being read by the other side of the machine. In this case, the back scattered radiation produced by the entrance beam below the table is mostly towards the floor and lower extremities of the radiation worker. Scatter coming out of the exit radiation from the patient is also present but reduced in intensity as compared with the entrance scatter below the table. Not all units are designed in this manner, however, and these scattered rays will be present in the imaging room until the diagnostic x-ray machine is turned off.2
What are the effects of scatter radiation on the human body?
Professionals performing diagnostic imaging procedures, such as radiologic technologists, are those most susceptible to scatter radiation emanating from a patient. Scatter radiation does not have as much energy as a primary X-ray beam does but over time it still can cause harm without technologists taking appropriate protective measures. This is a real risk for radiation workers, as they are potentially exposed to scatter radiation multiple times a day while running patients through their diagnostic imaging.
Without appropriate protection, radiation workers will begin to experience adverse health effects from prolonged scatter radiation exposure. This is because radiation has the potential to damage living tissue and organs.3 Severity of damage scope is dependent upon several factors:
the manner and length of time exposed
characteristics of the exposed person
the type of radiation
any involved radioactive isotopes
the sensitivity of affected tissue and/or organs
Since scatter radiation exposure is at lower energy and accumulated over longer periods of time (because technologists are performing X-ray procedures as a daily task), the risks of adverse effects are not as severe. However, radiation workers face an increased risk of cancer over a lifetime if protection is not made a priority in the workplace.4
Protection from your occupational exposure
Radiation worker protection should take as much priority as patient protection when it comes to radiation exposure. The ALARA principle is the standard for keeping radiation exposure “As Low As Reasonably Achievable”. As such, following these practices would be our top recommendation for limiting occupational exposure, with a couple additions. Here are the four ways to be best protected from scatter radiation:
Time
Limit the time that you spend near a radiation source while working. The more time that you are exposed to scatter radiation increases the possibility for a higher overall dose. If you must work near a source of radiation, work as quickly as possible and then leave the area to avoid spending more time around the source than necessary.
Distance
The second ALARA principle, distance, encourages distancing yourself from radiation sources. Radiation exposure decreases with distance, following an inverse square law for a point source. Doubling your distance will cause dose rate to go down by a factor of four. A “general rule of thumb” you can calculate is that any scatter radiation one meter from the side of the patient will be 0.1% of the primary x-ray beam intensity.5 This is helpful to keep in mind when considering how much distance you’re able to maintain during patient treatments.
Shielding
Shielding is the well-known practice of placing a barrier between you and a radiation source for minimizing exposure. The material for these barriers normally depends on radiation source type. For any radiation, though, the shielding should be something that absorbs radiation such as lead, concrete, or water. The practice of shielding can also include personal protective equipment (PPE) directly worn by individuals, such as thyroid shields, radiation protection glasses, and lead vests. For scatter radiation, a combination of moveable shields either suspended from the ceiling or on rollers in addition to fixed table shields are ideal.6 In general, shields are placed close to the source as that allows for a greater solid angle to be covered.
Dosimetry Program
As medicine and medical technology advances, the use of radiation has become more ubiquitous; there is now a greater risk of ionizing radiation exposure for occupational workers. The need for effective radiation monitoring has become more crucial to account for these modern practices.
Radiation dosimeters worn on the body are able to provide a record of absorbed dose from ionizing radiation. Although the measurement of exposure so obtained is not direct protection, being able to track your absorbed dose is essential to the practice of radiation safety. Through regular dose readings, you can know if you’ve reached or are close to reaching the annual NRC occupational dose limits. In the long run, this is a great method for protection against scatter radiation; should you exceed dose limit, you can adjust your work for the rest of the year to avoid further exposure. Thanks to dosimetry programs, radiation workers can stay informed and avoid potential risks better than ever.
The Take-Away
Scatter radiation, even if not as potent as a primary radiation dose, can still have adverse effects over time. To avoid potential increases to your risk of cancer down the road, it’s essential to maintain protective habits when performing diagnostic imaging procedures. Following the ALARA principles and remembering the long-term value of a dosimetry program can keep exposure to scatter radiation and its negative health effects to a minimum.
Versant Physics’ dosimetry management services are available to help your company take that step further in scatter radiation protection. Learn more about our knowledgeable support team and the Instadose family of dosimeters today. For more information regarding shielding, scatter radiation, and applicable policies for a medical radiation safety officer, try our online MRSO or Medical X-Ray courses.
References
What is primary radiation and secondary radiation? Reimagining Education. Published August 26, 2022. Accessed February 20, 2023. https://reimaginingeducation.org/what-is-primary-radiation-and-secondary-radiation/
Lambert K. hps.org. Health Physics Society. Accessed February 20, 2023. https://hps.org/publicinformation/ate/q11396.html
Radiation and health. Who.int. Accessed February 20, 2023. https://www.who.int/news-room/questions-and-answers/item/radiation-and-health
Morgan WF, Sowa MB. Non-targeted effects induced by ionizing radiation: mechanisms and potential impact on radiation induced health effects. Cancer Lett. 2015;356(1):17-21. doi:10.1016/j.canlet.2013.09.009
Lovins K. hps.org. Health Physics Society. Accessed February 20, 2023. https://hps.org/publicinformation/ate/q11780.html
Klein LW. Proper Shielding Technique in Protecting Against Scatter Radiation. Vascular Disease Management. Published June 2021. Accessed February 20, 2023. https://www.hmpgloballearningnetwork.com/site/vdm/commentary/proper-shielding-technique-protecting-against-scatter-radiation
Coming full circle to another new year invigorates millions. It is a time to reflect and develop goals for a better self, career, or quality of life. Versant Medical Physics & Radiation Safety also looks eagerly into 2023 and new opportunities of growth. We strive to provide our services to continuously benefit existing or future clients—even while appreciating our building-block actions of 2022. Even as our teams replace calendars in the office and spread poor puns about not seeing each other since last year, we shape our goals to provide exceptional support for healthcare providers to ensure safe workplaces and practices:
Remaining at the Forefront of Medical Physics and Radiation Safety
Sometimes the best resolution is to maintain healthy habits achieved from the year before. Versant Physics will continue its focus on sustaining its status as a trusted, knowledgeable business. Our consulting services demonstrate excellence within medical physics and radiation safety and will continue to in 2023. This involves keeping up with new discoveries in science, seeking value-add opportunities, and ensuring our provided support is top quality. It is with this idea that we strive to keep our competitive edge in all aspects.
Maintaining an edge means aligning ourselves with strong sources when the chances arise. In the past year, Versant acquired Radiological Physics Services, Inc (RPS) and completed a business merger with Grove Physics, Inc. We were excited to welcome Joseph Mahoney from Grove Physics as the new Vice President of Diagnostic Physics. Additionally, Versant brought in the talents of Ray Carlson and his team within RPS. The overall consolidation of these companies’ resources with Versant’s has increased services towards our clients. We are enthusiastic about efficiently using these combined assets to their full potential in 2023.
Another constituent to higher performance levels becoming achievable in the new year is that Versant Medical Physics achieved their ISO/IEC 27001:2013 certification in 2022. This certification demonstrates our dedication to being a trusted source. Not only can we be sought for our expertise in the field, but now to maintain personal information and customer data through even better safeguards in 2023. Being certified for strict security and compliance standards allows for peace of mind to clients using our Odyssey software; the protection of which is performed by our own security management team.
As a web-based, modern management system, Odyssey’s enhanced security is not its only feature that is being refined. Odyssey is kept as a radiation software suite that our clients can trust for the central administration of radiation safety programs. This is accomplished by our development team’s dedication to the software’s continuous improvement based off internal and external feedback. Radiation safety programs can quickly become complex and difficult to manage for healthcare companies, large or small. In addition to Versant’s experienced personnel, Odyssey provides clients an all-in-one platform to manage their program more easily and effectively. Within 2023, Versant’s development team will be focusing on projects to publish customizable reports. They will also revamp the centralized audit logging in Odyssey as part of software enhancement requests received through the feedback system.
Radiation Safety Implementation and Maintenance
Radiation safety has an extensive list of requirements and regulations set through organizations such as the NRC. The necessity of radiation safety programs is unquestionable when working with radioactive substances or ionizing radiation generating equipment. However, the issue remains that implementation and maintenance of these programs can become complicated fast. In 2023, Versant Medical Physics will assist healthcare providers simplify program compliance, protecting their employees and overall business.
Versant provides a variety of services, from dosimetry management to the support of our physicists, Radiation Safety Officers, and specialists. These professionals’ collective years of experience range over key modalities of radiation safety:
Any company—regardless of size—can run their badge program through our dosimetry monitoring services. Doing so assures access to our competent technical support team that can accommodate any company’s needs. Dosimetry badge management is top priority for this team to make your program easier to handle. The support team provides technical and customer service to your employees, so they understand best practices for the dosimeters they wear and to simplify compliance. This lets your employees quickly get back to what they do best: providing healthcare to those who need it.
Versant Medical Physics has board-certified physicists that cover regulatory and diagnostic services across the board. Versant’s physicists are driven to provide top-tier assistance so that our clients meet regulatory guidelines and ALARA fundamentals easily to protect people: employees, patients, and the general population. We will continue to achieve this in 2023 through provision of full-service support for your company’s radiation safety program’s crucial areas. These services can include but are not limited to equipment testing, radiation shielding and design, and comprehensive audits.
Medical Physics and Radiation Safety Certification and Training Support
Another component of medical physics and radiation safety is requirement (depending on role) of being certified for one’s work. Certifications in this field surround topics such as radioactive material handling in a continually evolving medical field. Our online continuing education training courses are available at any time to earn certifications approved by CAMPEP, AAHP, and ASRT. Many professionals within the medical physics and radiation safety fields need continuing education credits; this can be for compliance purposes or to take on new responsibilities within their company. In addition to providing support for our clients, Versant provides certified courses such as
Medical Radiation Safety Officer (MRSO) Training – Compliance knowledge and lectures provided to learn day-to-day requirements for a new Medical RSO. This course has been complimented for its clarity and precision of material.
Medical X-Ray Radiation Safety Training – Designed for anyone managing a radiation safety program or working with radiative machines in a medical environment. This course is practical and informative to prepare for any inspection.
Fluoroscopy Courses – Safety training that details optimization of fluoroscopy techniques while maintaining ALARA practices. This course has been recognized by previous customers for being comprehensive with employable practices.
Department of Transportation (DOT) Training – A combination of safety training for radioactive material transport and general handling. Usable for anyone within the shipping process such as technologists.
Our board-certified physicists are available through online communication to assist with questions or understanding of the content. This ensures that students feel supported through the process. By the end, each student can walk away with an accredited certification for the betterment of their career. Versant Medical Physics will ensure this content reaches as many people as possible to deepen their knowledge base in 2023.
Connecting and Sharing Ideas
Over the last decades, social media became an increasingly significant channel of communication for businesses. As a platform to promote their services and generate brand, companies connect in fashions more popular with the public. Although Versant has seen increases in our reach through social media followings and to the visitors of our website, there are still opportunities to further connect with our fellow companies, clients, and acquaintances within the medical physics and radiation safety fields.
In 2023, Versant Physics will bring a stronger focus into revitalizing our most popular channels for engaging content: our blog and podcast. Versant’s blog is a space for informational posts about radiation in the world and its various practices/safe handling in healthcare, as well as general tutorials on our Odyssey software. With the VersantCast Podcast, hosted by our very own medical physicist, Dr. Eric Ramsay, we take our listeners through various topics surrounding radiation, physics, and healthcare with the expansive knowledge of special guests. We are excited to work back into periodic postings and create subject matter that informs, inspires, and educates both readers and listeners alike.
Versant will also strive to further our network through our most popular social media platforms, being LinkedIn, Facebook, and Twitter. Even as a small company in a niche field, social media gives us the opportunity to connect with other people and businesses within the medical physics and radiation safety industry. Creating spaces to share ideas and new discoveries in science are beneficial to us as well as our followers to further our security in the knowledge surrounding the many fields that handle radiation. To join Versant in our goal to be more connected within the industry, you can follow us on LinkedIn, Facebook, and Twitter.
A Leadership Team that Inspires
Our devoted leadership team’s optimistic goals have shaped the future of Versant Medical Physics since 2016 to bring today’s success. Closing out our list of resolutions, our members of leadership provided what they strive to see to fruition in 2023:
Marcie Ramsay – President, CEO
“As president, I hope to continue providing a positive and supportive workplace environment for our professionals. The new year will also bring the opportunity for me to encourage our team to explore new areas of personal interest and work-life balance through Versant Physics’ recent subscription to the online education platform, MasterClass. On a personal note, I intend to devote more time to daily meditation and reflection.”
Eric Ramsay – Vice President, Commissioning
“Techniques for treatment in Radiation Therapy get more complex each year. Keeping up one’s knowledge base and gaining expertise in new modalities is challenging with a busy schedule. So, a suitable (and frankly, essential) resolution for the new year will be to focus on continuing education and professional development. This involves staying up to date with the latest research and techniques in the field, attending conferences and workshops, as well as seeking out opportunities for collaboration and networking with other professionals including the staff physicists at Versant. This resolution also includes taking steps to maintain a healthy work-life balance as burn out doesn’t help anyone.”
Ben Ramsay – Vice President, Technology & Finance
“Continue to develop a security mindset. With the increase in cyberattacks globally, and the risks internal and external to Versant, establishing a security-focused mindset is one of our goals in line with our ISO 27001 certification. I will also be focusing on improvement of Odyssey usability for existing clients and ways to bundle the software into our services with non-Odyssey customers that will provide enhanced value. Lastly, Versant will benefit from focuses on cross training staff in 2023 so that we are more flexible and capable of maintaining the highest levels of service possible.”
Joseph Mahoney – Vice President, Diagnostic Physics
“In 2023, I will be aiming for improved frequency and clarity of our client communication. Staying up to date and responsive towards the ever-changing regulatory environment will also allow for a strong start into the new year. Aligning with Versant’s desire for our teams to maintain work-life balances, there will be a strong focus in optimization of physical presence for our staff of physicists in geographic regions only where they are most needed so that they all can get back home more often.”
Dental x-rays are important for maintaining an individual’s optimal oral health. Like with any x-ray procedure, there are radiation safety principles that have been put in place to protect both patients and dentistry professionals.
Why are Dental X-rays Important?
Dental x-rays are an essential part of maintaining a healthy jaw and teeth. This diagnostic tool allows dentists to take a more in-depth look at what’s going on inside a patient’s mouth. Some dental problems affecting the roots of a tooth or that exist below the gum line cannot be diagnosed through a simple visual exam.
What Can a Dental X-ray Be Used for?
Dentists use dental x-rays to diagnose a variety of dental conditions, including:
Gum disease
Cavities and tooth decay
Impacted teeth
Cysts
Abscesses
Jaw disorders
Sinus issues
Bone loss
These x-rays are also beneficial for individuals who smoke, have a history of restorative dental work, or drink an excessive number of sugary drinks like pop or juice.
Radiation Safety for Patients During Dental X-rays
Most patients will undergo at least one of two different types of dental x-rays during their annual or bi-annual visit to the dentist. Each has its own radiation protection requirements to limit the patient’s radiation dose.
Bitewing X-rays
Bitewing x-rays are a type of intraoral x-ray. During a bitewing x-ray, the patient is required to bite down on a small tab attached to an x-ray film. There are usually 4 images taken to help dentists visualize all sides of the mouth.
Patients are usually required to wear a lead vest during a bitewing x-ray. Thyroid collars and leaded glasses can also be used to protect the eyes and sensitive areas of the throat.
Panoramic X-rays
Panoramic x-rays are extraoral x-rays used to diagnose dental problems in the jaw and skull. This 2D digital x-ray captures a single image of the entire mouth.
The machine has two sides. One side houses the x-ray tube, and the other houses the x-ray detector or x-ray film. The x-ray rotates around the patient’s head during this procedure to take the full image. A lead apron or thyroid protective collar may also be worn during this procedure as a safety precaution; however, it is not required.
Miscellaneous Dental X-rays
Other types of dental x-rays a patient may experience include a dental cone beam CT scan (3D image of the teeth and jaw) or a cephalometric projection (image of the entire head). These x-rays are not likely to occur during a routine visit.
Are Dental X-rays Safe?
Patients are exposed to extremely minimal radiation doses during dental x-ray procedures. A patient who undergoes a bitewing x-ray procedure will receive a radiation dose of 0.4 mrem, while a panoramic x-ray radiation dose exposure is approximately 0.7 mrem.
For comparison, the average U.S. citizen receives an annual radiation dose of 620 mrem. The sources of this radiation come from naturally occurring cosmic, internal, and terrestrial radiation, medical procedures like CT scans and conventional radiography procedures, and consumer products like tobacco, fertilizer, or welding rods.
As mentioned above, there are numerous protective measures put in place to help limit overall radiation exposure. Protective measures for patients during a dental x-ray include:
Using protective lead aprons and thyroid collars
Using modern x-ray equipment and up to date imaging techniques
Limiting the number of images taken in a year
The American Dental Association recommends that healthy patients receive x-rays once every 2 to 3 years to limit the amount of radiation exposure they receive.
Like any diagnostic procedure, the benefits of a dental x-ray far outweigh the low radiation dose a patient will receive. Dental x-rays can not only identify existing issues, but they can also identify potential problems that, if left untreated, could turn into serious or even life-threatening issues.
Radiation Safety for Dental Professionals
Radiation safety and radiation protection guidelines are especially important for dental professionals. The NRC regulates the amount of radiation exposure for adults who work with radioactive materials. Occupational exposure limits are limited to 5,000 mrem per year.
Dental professionals including hygienists, oral surgeons, and orthodontists, are required to adhere to these exposure limits. This profession receives less ionizing radiation exposure than other healthcare professionals on average. However, basic protective measures help limit their occupational radiation exposure and keep up with ALARA standards.
Personal Dosimeter
Dental professionals should wear a personal dosimeter when operating x-ray equipment to record their dose.
The Instadose+ dosimeter is an affordable personal dosimeter option that provides dentists and dental professionals with accurate, long-term exposure tracking. The device wirelessly captures, transmits, measures, and analyzes radiation dose exposure. Dental professionals can access their read history on-demand and in real-time thanks to the device’s Bluetooth and SmartMonitoring technology.
Unlike traditional film badges, the Instadose+ dosimeter does not need to be collected and processed off-site.
Time, Distance, and Shielding
The standard guidelines for minimizing dental professionals’ exposure are time, distance, and shielding. This means limiting the amount of time spent around a radiation source, maintaining a safe distance away from the source of radiation, and standing behind protective barriers during a procedure.
During a routine dental visit, hygienists are often the ones who prepare and take the dental x-ray. To limit their exposure from taking these images multiple times a day, hygienists will usually leave the room to increase their distance from the x-ray tube. They may also stand behind a lead wall or partition while the image is being taken.
The Takeaway
Dental x-rays are a necessary part of maintaining good oral health. Radiation safety guidelines like wearing lead vests and thyroid collars are important for limiting patient exposure during routine checkups. Wearing a personal dosimeter and following time, distance, and shielding guidelines are also necessary for limiting occupational exposure.
We are often asked questions about applying for or changing licenses to possess and use radioactive materials. There are many different types of licenses; choosing amongst them can be confusing. In this post, we will discuss four common types.
With some exceptions, approval by a regulatory agency (U.S. Nuclear Regulatory Commission or equivalent state agency), in the form of a license, is required to use and/or dispose of radioactive materials.
The type of license authorizing the purchase, possession, use, and disposal of radioactive materials is based on several factors:
Type, form and quantity of radioactive materials requested
Proposed use(s)
Experience of the proposed licensee with managing the use of radioactive materials
Types of licenses include, but are not limited to:
Limited scope specific academic and research and development
Limited scope specific medical use
Broad scope specific
Broad scope specific medical use
In this post, we will discuss the regulations under which the U.S. Nuclear Regulatory Commission (NRC) issues two common types of licenses: (i) limited scope specific and (ii) broad scope specific. Some states, called Agreement States, have the authority under NRC regulations to issue licenses. Their regulations are equivalent to NRC regulations.
1. Limited Scope Licenses
These licenses are issued to applicants subject the following limitations:
Radionuclides
Specified chemical and physical form(s)
Possession limits
Proposed use(s)
Radiation Safety Officer (RSO)
Authorized User(s)
Location(s) of use
TheRSO’s training and experience should be applicable to and generally consistent with the types and quantities of licensed materials listed on the license. Authorized users (AUs) must have adequate training and experience with the types and quantities they intend to use (NUREG 1556, Vol. 7, Rev. 1). The applicant must submit to the regulatory agency for review and approval the specific training and experience of each proposed user and the facilities and equipment available to support each proposed use.
If the licensee wishes to change any of these limitations or add or remove an Authorized User (AU), permission must be sought from the issuing regulatory agency to amend the license.
Medical Licenses – general comments
Licensing for the use of radioactive materials to diagnose and treat human disease is subject to more complex regulations than the academic and research and development licenses described above. A wide variety of radionuclides and physical and chemical forms are used for a multitude of purposes in human medicine. Consequently, AUs and the RSO must meet specific and extensive training and experience criteria focusing on the type, form, and quantity to be used as well as the intent of the use (diagnosis vs. treatment).
radiation safety commensurate with use of radioactive materials;
administration of a radiation dose or dosage and how it is prescribed;
direction of individuals under the AU’s supervision in the preparation of radioactive materials for medical use and in the medical use of radioactive materials; and
preparation of a written directive, if required.
To be named as an AU on a medical license, the individual must satisfy one or more of the requirements outlined in Subparts D, E, F, G or H of 10 CFR 35. In general, this requirement can be met by:
being board certified in a specialty medical discipline appropriate to the intended use that is recognized by the Commission or Agreement State; or
being named as an AU on another license issued by the Commission or Agreement State for the same or similar type, form, and quantity of radioactive materials in question; or
having completed training and experience as specified in the regulations.
The RSO on a medical license must satisfy the training and experience requirements outlined in 10 CFR 35.50:
be certified by a specialty board whose certification process has been recognized by the Commission or an Agreement State; or
have completed a structured educational program as outline in 10 CFR 35.50(b); or
be a medical physicist who is certified by a specialty board recognized by the Commission or an Agreement State, has experience with the radiation safety aspects of similar types of radioactive materials for which the licensee seeks approval and has training in the radiation safety, regulatory issues, and emergency procedures for the types of use for which a licensee seeks approval; or
be a medical AU, authorized medical physicist, or authorized nuclear pharmacist identified on a Commission or an Agreement State license, a permit issued by a Commission master material licensee, a permit issued by a Commission or an Agreement State licensee of broad scope, or a permit issued by a Commission master material license broad scope permittee, has experience with the radiation safety aspects of similar types of use of byproduct material for which the licensee seeks the approval and Is an authorized user, authorized medical physicist, or authorized nuclear pharmacist identified on a Commission or an Agreement State license, a permit issued by a Commission master material licensee, a permit issued by a Commission or an Agreement State licensee of broad scope, or a permit issued by a Commission master material license broad scope permittee, has experience with the radiation safety aspects of similar types of use of byproduct material for which the licensee seeks the approval.
2. Limited Scope Specific Medical Licenses
A specific license of limited scope may be issued to private or group medical practices and to medical institutions. Each type, form, quantity and use and condition of use of radioactive materials as well as the RSO and AU(s) are named on the license (NUREG 1556 Vol. 9, Rev. 3). These licenses may also be issued to an entity requesting authorization to perform mobile medical services and certain non-medical activities such as self-shielded blood irradiators. Changes to any of these specifications or conditions must be requested and approved by amendment.
Research Involving Human Subjects
“Medical use” of radioactive materials includes administration to human research subjects. A license condition authorizing such research is not required if the research is conducted, funded, supported or regulated by a Federal Agency that has implemented the Federal Policy for the Protection of Human Subjects. Otherwise, the licensee must apply for and receive an amendment before conducting such research. In all cases, licensees must obtain informed consent from the human subjects and prior review and approval by an Institutional Review Board. All research involving human subjects must be conducted only with the radioactive materials listed in the license and for the uses authorized in the license (NUREG 1556, Vol. 9, Rev. 3).
Research involving human subjects may be conducted under either limited scope or broad scope specific licenses.
3. Broad Scope Specific Licenses
Broad scope specific licenses generally authorize possession and use of a wide range of radioactive materials. Because regulatory agencies grant significant decision-making authority to broad scope licensees through the license, a broad scope license is not normally issued to a new licensee. An applicant for a broad scope license typically has several years of experience operating under a limited scope license and a good regulatory performance history (NUREG 1556 Vol. 11, Rev. 1). Changes to the radiation safety program approved via in-house review and approval by the RSO and/or RSC (see below) do not appear on the license but are subject to review by regulatory agencies during routine inspections.
Title 10 of the Code of Federal Regulations (10 CFR) Part 33, “Specific Domestic Licenses of Broad Scope for Byproduct Material,” provides for three distinct categories of broad scope licenses (i.e., Type A, Type B, and Type C), which are defined in 10 CFR 33.11, “Types of Specific Licenses of Broad Scope.”
Type A
Type A licenses of broad scope are typically the largest licensed programs and encompass a broad range of uses. Licensees use a Radiation Safety Committee (RSC), radiation safety officer (RSO), and criteria developed and submitted by the licensee and approved by the NRC during the licensing process to review and approve all uses and users under the license.
An applicant for a Type A broad scope license must establish administrative controls and provisions related to organization and management, procedures, record keeping, material control, and accounting and management review necessary to ensure safe operations, including:
establishment of an RSC
appointment of a qualified RSO
establishment of appropriate administrative procedures to ensure the following:
— control of procurement and use of byproduct material
— completion of safety evaluations of proposed uses that take into consideration adequacy of facilities and equipment, training and experience of the user, and operating and handling procedures
— review, approval, and recording by the RSC of safety evaluations of proposed uses
use of byproduct material only by, or under the direct supervision of, individuals approved by the licensee’s RSC
Because these controls and provisions have been established, the applicant may approve in-house, without requesting amendment:
Authorized Users
location of use within the confines of the physical location(s) listed on the license
changes in use of radioactive materials so long as the use is consistent with the license conditions and appropriate safety evaluations have been performed, documented, and approved by the RSC
The requirements for issuance of a Type A broad scope license are described in 10 CFR 33.13, “Requirements for the Issuance of a Type A Specific License of Broad Scope.”
Type B
Type B broad scope licensed programs are normally smaller and less diverse than Type A broad scope programs. Type B broad scope licensees use an RSO and criteria developed and submitted by the licensee and approved by the NRC during the licensing process to review and approve all uses and users under the license. Because the RSO reviews and approves all uses and users under the license, rather than a full RSC, as established for Type A broad scope programs, the types and quantities of byproduct material authorized by the Type B broad scope license are limited to those described in 10 CFR 33.11(b) and 10 CFR 33.100, “Schedule A,” Column I. Generally, the scope of authorization for Type B licenses is limited to the experience and knowledge of the RSO.
Changes to the type, form and quantity of radioactive materials may have to be approved by the regulatory agency by amendment, depending on the specific provisions of the license.
The requirements for issuance of a Type B broad scope license are described in 10 CFR 33.14, “Requirements for the Issuance of a Type B Specific License of Broad Scope.”
Type C
Type C broad scope licensed programs typically are issued to institutions that do not require significant quantities of radioactive material but need the flexibility to possess a variety of different radioactive materials. Users of licensed material under these programs are approved by the licensee based on training and experience criteria described in 10 CFR 33.15(b). The types and quantities of byproduct material authorized by the Type C broad scope license are limited to those described in 10 CFR 33.11(c) and 10 CFR 33.100, Schedule A, Column II, again, considering the unity rule.
While 10 CFR 33.15 does not require Type C broad scope licensees to appoint an RSO, the licensee must establish administrative controls and provisions related to procurement of byproduct material, procedures, record keeping, material control and accounting, and management review to ensure safe operations. This should include the appointment of someone responsible for the day-to-day operation of the radiation safety program, such as an RSO.
Changes to the type, form and quantity of radioactive materials may have to be approved by the regulatory agency by amendment, depending on the specific provisions of the license.
The requirements for issuance of a Type C broad scope license are described in 10 CFR 33.15, “Requirements for the Issuance of a Type C Specific License of Broad Scope.”
4. Broad Scope Medical Licenses
The NRC issues specific licenses of broad scope for medical use (i.e., licenses authorizing multiple quantities and types of byproduct material for medical use under 10 CFR Part 35, as well as other uses) to institutions that (i) have experience successfully operating under a specific license of limited scope and (ii) are engaged in medical research and routine diagnostic and therapeutic uses of byproduct material (NUREG 1556, Vol. 9, Rev. 3). Typically, these are large medical centers/teaching hospitals that have a need to administer or use a wide variety of radionuclides and/or radiopharmaceuticals for diagnosis and therapy. Because these institutions have complex programs, the authority to approve changes in-house makes the program flexible and nimble.
AUs and the RSO on a broad scope medical license must meet the same criteria for training and experience as for a limited scope medical license discussed above.
Regulatory Services by Versant Physics
Our team of experienced Radiation Safety Officers can help you navigate the NRC regulations and determine which license type is appropriate for your facility. Contact sales@versantphysics.com to speak to a team member or learn more about our Regulatory services.
Under the guidance of Lee Myers, Program Director, Versant Medical Physics’ residency program will be working with affiliated clinical facilities, Anne Arundel Medical Center and Hahne Regional Cancer Center. Our intensive 2-year program offers residents an incredible opportunity to learn from our own team of experienced medical physicists, as well as the knowledgeable faculty at each clinic.
Today’s route to becoming a Board-Certified Medical Physicist is through the successful completion of a Medical Physics degree, or its equivalent, from a CAMPEP-approved university program, which is then followed by the successful completion of a CAMPEP-approved Medical Physics Residency program. Versant Medical Physics made the decision to support and sponsor our Residency in an effort to “do our part” in making sure graduating medical physics colleagues have more opportunities to become board-certified.
For more information regarding our residency program,
Please contact Lee Myers at lee.myers@versantphysics.com.
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