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29 Jun 2022
Straw hat, bright red glasses and orange bottle of sunscreen for sun protection
Health Effects, Non-ionizing radiation, Radiation Safety Versant Physics 0 comment

Ultraviolet Radiation: How to Protect Yourself

Summer is in full swing. As a result, many Michiganders are spending more time in the great outdoors taking advantage of the warmth and sunshine.

However, the more time a person spends outdoors the more their body is exposed to Ultraviolet (UV) radiation. UV radiation, a form of non-ionizing radiation, is invisible to the human eye and cannot be felt. It can cause severe skin damage and lead to the development of skin cancer.

Here at Versant Physics, our focus is primarily on radiation safety in relation to ionizing radiation sources used in medical procedures and cancer treatments. However, it is just as important that you protect yourself from naturally occurring UV radiation and understand the potential health risks.  

In honor of UV Safety Month, we’ll explain what UV radiation is, the most common types of skin cancer and other health risks associated with UV radiation, and important protective measures you should take when out in the sun.

What is UV Radiation?

Ultraviolet (UV) radiation is a non-ionizing form of electromagnetic radiation that has both natural and artificial sources. Most of the UV radiation from sunlight gets absorbed by Earth’s atmosphere. What doesn’t get absorbed makes its way to the surface and interacts with our skin. UV rays are present even on cloudy days and also reflect off surfaces like snow, sand, and water.

There are three types of UV radiation rays:

  • Ultraviolet A (UVA)
  • Ultraviolet B (UVB)
  • Ultraviolet C (UVC)

UVA rays have the lowest wavelength of the different types of UV radiation; however, they make up over 95% of the rays that reach the Earth’s surface. These rays penetrate through the layers of skin, damaging the elastin and collagen. This results in tanned skin and skin aging, often in the form of wrinkles or age spots.  

UVB radiation is made up of high-energy UV rays that interact with the top layers of skin. UVB rays interact with skin cells and damage them, causing DNA mutations that show up later in the form of sunburns, skin cancer, or cataracts.

UVC rays are the strongest of the UV rays. Almost all of this UV radiation is absorbed by Earth’s atmosphere.

Unprotected, prolonged exposure to UV radiation from the sun is connected to a variety of health risks, including:

  • Premature aging
  • Skin damage
  • Cataracts
  • Immune system suppression
  • Skin cancer

UV Radiation Exposure and Skin Cancer

UV radiation causes melanoma and nonmelanoma skin cancers called basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).

Melanoma

Melanoma is a type of skin cancer that forms in the melanocytes. These cells are located beneath the squamous and basal cells and are what produce melanin, the pigment that gives hair, eyes, and skin its color.   

Melanoma is less common than other types of skin cancer, however, it is more dangerous. This is because melanoma it more likely to spread to other parts of the body if left untreated. Melanoma often presents as a highly pigmented black or brown tumor on the torso, chest, neck, or face.

The “ABCDE” rule can help patients identify if their existing mole or new skin growth is a warning sign of melanoma:

  • Asymmetry. The two halves of the mole do not match.
  • Border. Normal moles have a clean, even border. Melanoma will present with uneven or ragged edges.
  • Color. Melanoma tumors can be black, brown, pink, red, or white.
  • Diameter. Melanoma is usually a growth larger than a pencil eraser, or ¼ inch in diameter.
  • Evolving. The existing mole or new growth is changing in size, shape, texture, or color. It also may begin to itch, bleed, or ooze.

People with light skin, eyes, and hair are considered more at risk of developing melanoma than people with darker skin. Age, gender, occupation, family history, and lifestyle choices also play a role in the level of risk associated with developing melanoma.

Nonmelanoma Skin Cancers

Basal cell carcinoma is the most common type of skin cancer that begins in the basal cells. It shows up on areas of the body that are frequently exposed to UV radiation from sunlight, such as the head, face, or neck. It normally presents in the form of a skin lesion or shiny, skin-colored bump.

Squamous cell carcinoma is less common but just as serious. It presents as open sores, thick or wart-like skin, raised growths, or scaly red patches that may itch or bleed. SCC can show up anywhere on the body, although they are most often found on areas of the body that are frequently exposed to the sun.

Both BCC and SCC grow relatively slowly and are highly treatable. The sooner a new or strange-looking growth is looked at by a dermatologist and diagnosed, the better the odds are of treating the skin cancer. However, if left untreated, these skin cancers can spread to other areas of the body and become more dangerous.

UV Radiation Protection

There are many simple protective measures the average person can implement to help lessen the risks associated with UV radiation and its negative side effects.

  • Seek shade
  • Avoid prolonged sun exposure from 10 a.m. to 4 p.m. when the sun is strongest
  • Wear long sleeves or pants
  • Wear a hat and/or UV-blocking sunglasses
  • Wear a broad-spectrum sunscreen

Sunscreen is a major protector against UV radiation. Broad-spectrum sunscreens protect the skin from both UVA and UVB rays. Wearing a minimum of SPF 15 can reduce the risk of developing melanoma by 50% and SCC by 40%. Wearing a protective sunscreen daily can also help prevent premature skin aging.

Are There Any Health Benefits to UV Radiation?

Exposure to natural UV radiation from the sun has an important health benefit for the human body. UV radiation helps our bodies produce vitamin D, which is an essential vitamin that absorbs calcium in our stomachs, reduces inflammation, and is needed for healthy bone growth. Some food products contain vitamin D however most people get a portion of their vitamin D needs through sunlight.

There are no hard and fast numbers detailing how much sunlight exposure is needed for optimal vitamin D synthesis. The World Health Organization recommends no more than 15 minutes of direct sun exposure at least 3 times a week.

However, this does not negate the need for sun protection measures such as sunscreen and wearing protective clothing.

The Takeaway

It is important to protect yourself from UV radiation any time of the year. Although this non-ionizing source of radiation can help our bodies create vitamin D, it also interacts with our skin in a way that can lead to skin cancer. To prevent this, you should wear and apply sunscreen as directed, invest in UV-blocking glasses and clothes, and try to stay out of the sun as much as possible.

Learn more about UV and sun safety here.

24 Jun 2022
Brachytherapy, Radiation Safety Versant Physics 0 comment

Radiation Safety and Brachytherapy Procedures

Brachytherapy is a procedure that involves placing radioactive material sources inside the body, either directly inside or next to a tumor. Also known as “close” radiation, this procedure is used to treat cancer by allowing doctors to deliver higher doses of radiation via a needle or catheter to specific areas of the body.

Areas of the body commonly treated using brachytherapy include the head and neck, skin, breast, cervix, lung, prostate, uterus, and eye. Brachytherapy implants can be temporary or permanent, depending on the type of treatment needed.

Brachytherapy targets the tumor directly, which increases exposure to the cancerous cells and reduces radiation exposure to the surrounding healthy cells. Because of the targeted nature of brachytherapy, it is best used for cancers that have not metastasized. It is considered as effective as—and sometimes used in conjunction with—external beam therapy.

Types of Brachytherapy

There are three types of brachytherapy:

  • High-dose rate (HDR) implants

HDR implants are inserted into the body and left in for brief sessions of 5-20 minutes before being taken out. These sessions can occur multiple times a day over a period of weeks, depending on the type of cancer being treated and the patient’s overall health. This is typically an outpatient procedure.

Radiation Risks:

HDR procedures are typically performed in a radiation therapy vault. No visitors are allowed during the treatment. Because HDR implants are temporary, a person receiving this therapy will not give off radiation once the implant is removed. Therefore, it is unnecessary for family members or visitors to take precautions after treatment.

  • Low-dose rate (LDR) implants

LDR sources are surgically implanted within or next to a tumor, where they remain in the body for 1-7 days. This procedure usually involves a hospital stay. When the treatment is finished, the doctor removes the radiation source and the catheter/applicator used to insert it.

Radiation Risks:

Radiation exposure risk to others is low with LDR implants. However, depending on the source used, radiation rates around the patient can be elevated while the source is in place. Because of this, in some cases, it is recommended that patients:

  • Limit the number of visitors during treatment
  • Limit the time spent with visitors during or between treatments
  • Limit time spent with children and pregnant women

Permanent brachytherapy is another type of LDR brachytherapy that involves inserting a needle filled with radioactive seeds into the tumor, with the help of an ultrasound or CT. These seeds are often made of metal, are roughly the size of a grain of rice, and contain radiation sources (iodine, palladium, cesium, or iridium).

The implants remain in the body permanently, however, the radiation they emit decreases over time. Eventually, almost all the radiation will go away. This type of brachytherapy is most commonly used for the treatment of prostate cancer.

Radiation Risks:

With this type of procedure, the radioactive source is not removed at the end of treatment. Therefore, it is important to initially limit time spent with pregnant women due to the low doses of radiation being emitted from the area being treated. Even after the implants have been in place for a long time, people with permanent implants can set off airport radiation sensors.

Radiation Protection

Modern brachytherapy techniques have largely eliminated the initial radiation exposure dangers that existed several decades ago. Most radioactive sources used for brachytherapy either incorporate a metallic shield within the applicator or use an isotope that emits low-energy photons that are shielded by the patient. Radiation does not travel far outside the treatment area, which means the chance of exposure to others is low.

However, there are recommended radiation safety precautions for both patients and medical professionals during a brachytherapy treatment. These may vary depending on the source and activity used for an individual implant.

  • HDR brachytherapy treatments are performed in a radiation therapy vault. The patient remains in the treatment room alone while the source is outside of its shielded housing to limit exposure to staff and members of the public.  
  • If visitors are allowed during the course of a temporary LDR treatment, they should spend no more than 30 minutes with the patient.
  • All implants are tested and sealed before they are implanted to ensure that the radioactive material inside of them does not leak. Their placement inside the body is also unlikely to change or move.

Side Effects of Brachytherapy

Because healthy tissue and organs surrounding the tumor are not as affected by the radiation treatment, most people experience fewer and less severe side effects than occur with external beam therapy.

In addition to tenderness, bleeding, or swelling in the treatment area, the side effects a patient could experience depend largely on the type of cancer and therapy being performed. Fatigue is common.

The side effects usually go away a few days after the treatment has ended. Ask your doctor or treatment team for more information on the types of side effects you may experience.

01 Jun 2022
Patient Wearing Head Coil During MRI Scan In Hospital
Diagnostic Physics, Medical Physics, Radiation Safety Versant Physics 0 comment

Diagnostic Medical Physics in Medicine: Why It’s Important

Many are unfamiliar with the important role that diagnostic medical physics plays in medicine, particularly in the diagnosis and treatment of diseases like cancer.

At Versant Physics, we provide a wide range of diagnostic medical physics services that help healthcare facilities safely and effectively execute procedures for the health and well-being of their patients. Our goal is to help facilities ensure their patients are protected from excessive levels of radiation and that diagnostic equipment is working appropriately, all while maintaining compliance with state and federal regulations.

In this blog post, we’ll break down what diagnostic imaging is, how and why physics principles are applied to diagnostic medicine, and the various roles of a diagnostic medical physicist to help clarify the importance of this profession.

What is Diagnostic Imaging?

Diagnostic Imaging is a range of techniques and equipment used to look inside the body. The purpose of this is to help physicians identify injuries and illnesses, and to help make an accurate diagnosis and treatment plan. This can include a variety of procedures, from simple X-rays for broken bones to more complex procedures involving the brain, heart, or lungs.

Diagnostic imaging procedures are usually painless and noninvasive. However, depending on the test being performed, some patients may be exposed to small amounts of radiation.

diagnostic medical physics

CT scans are a common example of a diagnostic imaging test that emits radiation. In a CT scan, the patient is exposed to a series of X-rays from a variety of angles which are then processed via a computer. The computer creates cross-sectional images of the inside of the body. CT scans are higher-quality images than a normal X-ray and allow physicians to view both hard and soft tissues in the body. They can check for stroke, internal bleeding, chest abnormalities, enlarged lymph nodes, abdominal or pelvic pain, tumors, and more. It is also used to monitor existing diseases such as heart disease and cancer. 

Other common diagnostic imaging procedures include mammography, which helps detect and diagnose breast cancer, fluoroscopy, magnetic resonance imaging (MRI), and ultrasounds.  

Diagnostic Physics and Medicine

Medical physics as a field is divided into five categories, including:

  • nuclear medicine
  • therapeutic medical physics,
  • medical health physics,
  • magnetic resonance imaging physics, and
  • diagnostic imaging.

Diagnostic medical physicists are responsible for ensuring the safe and effective application of radiation used in medical treatments. Specifically, radiology procedures. They work as a member of a patient’s care team, which typically includes physicians, dosimetrists, and radiologic technologists among others.

Equipment Evaluation and Compliance

One of the main roles of a diagnostic medical physicist is to ensure the safe operation of radiation-producing machines and diagnostic radiation detectors. This can include developing imaging equipment specifications, measuring the radiation produced by a piece of equipment prior to clinical use, and proving that the equipment is compliant with regulatory and accreditation requirements.

This also includes assessing all the software, algorithms, data, and computer systems associated with the radiation-producing equipment for accuracy and performance.

Acceptance Testing

Any unit that is used in a diagnostic setting must be periodically reviewed to ensure not only that the image quality is maintained, but that the unit is operating in compliance with the manufacturer’s specifications.

Most states require that a newly installed piece of diagnostic imaging equipment, whether it is brand new or used, be tested by a qualified medical physicist prior to first clinical use. This extremely thorough survey confirms that the unit was installed and set up correctly and ensures that it meets vendor and industry performance standards. It is also an opportunity to identify any potential issues with the unit before it is used on patients.

mammography unit

Typical units that require acceptance testing include fluoroscopic x-rays, radiographic x-rays, PET and PET/CT units, mammography equipment, C-arms, CTs, SPECT cameras, and PACS workstations.

Commissioning

The commissioning process for diagnostic radiation therapy machines such as Linear Accelerators involves testing the unit’s functionality and verifying that dose calculation algorithms work appropriately to produce measured dose calculations.  

Radiation-producing equipment like a LINAC is highly technical and specific. There are many requirements and protocols that detail how this unit should work, from how much energy it produces to the shape and direction of the beam. Diagnostic medical physicists are trained to measure, assess, and implement the optimal baseline values for a unit during the commissioning process.

Patient safety is the end goal of all diagnostic physics commissioning work.

Shielding

Another important aspect of diagnostic physics includes the planning and placement of shielding in areas that use radiation. In the United States, 35+ states require specific shielding designs in any room that houses radiation-producing equipment.

A diagnostic medical physicist can evaluate any shielding that is installed to determine if it will adequately protect workers, patients, and the public from the radiation outside of the scope of a specific treatment. This includes planning for material thickness as well as appropriate placement.

Versant Physics physicists are experienced with a range of equipment shielding requirements, including dental units, Cone-beam CTs, mobile c-arms, high-energy LINACS, Proton Therapy units, and Cyclotrons.

Our team is also experienced with different types of shielding materials, including non-lead materials, which are guaranteed to meet regulatory guidelines and ALARA principles.

Patient Dose & Treatment

Part of a diagnostic physicist’s job is also to ensure the safety of medical imaging modalities being applied in the treatment of individual patients.

They are responsible for determining the exact radiation dose a patient will receive in accordance with the radiation oncologist’s prescription before the patient begins treatment. Creating this therapy plan can take a few hours or multiple days, depending on the complexity of the illness. They also ensure radiation protection guidelines are in place, develop QA tools that ensure optimal image quality, and make sure that all operators are trained in the use of the best imaging techniques.

A diagnostic medical physicist may also monitor the dose of the patient throughout the course of their treatment.

Patients rarely interact directly with the medical physicist on their care team; however, they are a vital part of a safe and effective treatment process.

Versant Physics Diagnostic Support

Our board-certified physicists are able to handle diagnostic physics support for a variety of facilities, including hospitals, clinics, dental offices, and university health systems. With decades of experience, top-of-the-line equipment, and a passion for patient safety, our team is the best choice to assist with your diagnostic medical physics needs.

Contact us for a quote or to learn more about our medical physics support services.

20 May 2022
Orthopantomography of an adult patient, dentistry
Uncategorized Versant Physics 0 comment

X-Rays and Radiation Safety Principles in Dentistry

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.

dental x-ray

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.

Instadose+ Dosimeter

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.

28 Apr 2022
Radiation Protection Survey of Package with Pancake Probe
ALARA, Diagnostic Physics, Radiation Protection Survey, Radiation Safety Versant Physics 0 comment

A Beginner’s Guide to Radiation Protection Surveys

The purpose of a radiation protection survey is to identify higher-than-normal doses of radiation in medical environments, labs, and anywhere radiation-emitting machines or radioactive materials (RAM) are used. They are required by state and federal regulations to be performed regularly to ensure the safety of technicians, technologists, nurses, doctors, researchers, and patients.

In this brief guide we’ll talk about what a radiation protection survey is, why it is important, and the type of equipment required to perform a radiation protection survey.

What is a radiation protection survey?

Radiation protection surveys are a way to directly measure radiation levels and identify potential leakage through breaks or voids in shielding.

Surveys are performed on:

  • Diagnostic fluoroscopic and radiographic equipment
  • Non-medical industrial equipment such as those found in veterinary offices
  • CT and CBCT machines
  • Particle accelerators
  • Irradiators
  • Bone mineral densitometers
  • Cabinet x-ray machines
  • Areas that use sealed sources of RAM
  • Packages containing RAM

The Different Types of Radiation Surveys

Not all radiation surveys are created equal. Let’s talk about some of the different surveys you may encounter a need for in your radiation safety program.

Radiation Emitting Device Survey

X-ray machines and other radiation-emitting devices require regular surveys to be performed to confirm that the machine is operating as expected. Radiation producing machines are surveyed for:

  • Timer accuracy
  • Radiation output
  • Focal spot size
  • kVp and mA
  • Beam limitation accuracy
  • Filtration
  • Skin entrance exposure / rate of exposure
  • Scatter radiation measurements
  • Photo-timer operation
  • Proper signage, labels, and postings

If high or unexpected dose rates are measured during a survey, the machine should be turned off and undergo appropriate maintenance.

Area Survey

Area surveys are required anywhere a radiation device is in use and the potential for receiving a higher-than-normal radiation dose is present. These surveys are typically measured in milliRoentgen per hour (mR/hr). The Roentgen is a measure of the amount of ionization in the air from the radiation.

Anytime you have an area survey performed, you are required to keep the official records of the survey results for 3 years.

Contamination Wipe Test

A contamination wipe test, also known as an indirect or swipe survey, is used to identify radioactive material contamination on surfaces, equipment, and clothing such as those found in a lab. This type of survey can identify non-fixed radiation left behind from radioactive solids, liquids, or gasses.

Lab tech performing a wipe test

Wipe tests are recommended to be performed frequently, especially if you are a HAZMAT employee that receives or ships RAM packages. A wipe test involves wiping at least 300cm2 of the package’s surfaces using an absorbent material. Afterward, the activity on the swipe is measured assuming a removal efficiency of 0.1 unless the actual efficiency is known.

Users in lab settings typically survey their work areas after an experiment or when a minor spill is suspected.

Radioactive Sealed Source

A radioactive sealed source is a source of special form RAM that has been contained or encapsulated to prevent contamination. These sources can only be opened by destruction. Semi-annual surveys of these sources are required to check for leakage.

Bioassay Survey

Internal exposure monitoring, or a bioassay survey, is performed on individuals that use unsealed radioactive materials. The survey estimates the internal organ dose to determine if any RAM has entered the body. It can also help determine if RAM is present in the air.

Bioassay surveys are performed by analyzing blood, tissue, or urine samples or by carefully monitoring the presence and/or quality of isotopes present in the organ of concern.

How often do I need to have a survey performed?

The frequency of a radiation protection survey depends on several factors, most of which depend on different state and federal regulations.

  • When a new or used x-ray equipment is installed
  • When existing x-ray equipment has been moved
  • If shielding has been modified
  • After the equipment has undergone significant repairs
  • If a potential problem is indicated

Who performs these surveys?

In general, surveys on radiation-producing equipment are conducted by health physicists and medical physicists.

Is special equipment required for a survey?

Special equipment is required to detect ionizing radiation. Most equipment is hand-held measurement instruments called survey meters. This equipment is required to be calibrated annually to maintain accuracy and to ensure that reliable measurements are recorded.

Survey meters consist of:

  • A probe which produces electrical signals when it is exposed to radiation
  • A control panel readout with an electronic meter that gauges the amount of radiation exposure
  • A speaker which provides an audible indication of the radiation exposure

There are several different kinds of survey meters physicists use to perform radiation surveys.

Geiger-Mueller Pancake Probe

One of the more commonly used survey meters is the Geiger-Mueller Pancake Detector. Although there is no “universal” radiation detector, the G-M Pancake Probe comes pretty close. This is because the probe can detect alpha, beta, and gamma radiation, although they are generally used for detecting Beta Emitters. These probes come in a variety of models and configurations.

Surveying open package with pancake probe

The probe detects radiation by collecting counting gas within the tube. The counting gas is ionized when a photon or particle interacts with a released electron. When the voltage is high, radiation that interacts with the counting gas produces an electronic pulse that is measured with a separate counting instrument.

A pancake probe has a thin layer of mica on the active face of the detector, which allows most alpha and beta particles to interact with the counting gas inside the tube.

G-M Pancake Probes are frequently used to detect C-14, Ca-45, P-32, P-33, and S-35.

Scintillation Survey Meter

A scintillation survey meter is used to detect low-energy Gamma Emitters and x-rays. The scintillator, or sensor, is made of a transparent crystal or liquid which shines when it interacts with ionizing radiation. The scintillator is attached to a photosensor like a photomultiplier tube which detects the generated light.

This survey meter detects I-125 and Cr-51. They are an ideal equipment choice for surveying electron microscopes and x-ray diffractometers.

Diagnostic Physics Support and Radiation Surveys by Versant Physics

When it comes to hiring a consultant to perform radiation protection or QA surveys for your equipment, you want to make sure you’re working with the best. People who are experts in state and federal regulations regarding radiation machines and RAM, have access to top-of-the-line survey equipment and understand the importance of adhering to ALARA standards.

Versant Physics’ proactive and transparent diagnostic physics support process minimizes safety concerns and reduces the likelihood of compliance violations. We support our clients by sharing our knowledge of best practices in advanced technologies, and by utilizing a team-based approach we feel enables our clients to focus on maximizing the quality of patient care.

Contact our team for a free 30-minute consultation to learn more about our diagnostic physics and radiation survey expertise.

20 Apr 2022
nurse guiding patient entering mri scanner
ALARA, Health Effects, Radiation Safety, Radiation Shielding, Regulatory Versant Physics 0 comment

The Basics of Radiation Shielding in Medicine

Basic radiation protection guidelines can be summed up in three simple concepts: time, distance, and shielding. While both limiting the time spent and increasing the proximity to an ionizing radiation source is something that lies within the power of the individual, shielding and X-ray room design require careful planning and execution by the facility or Radiation Safety Officer.

What is radiation shielding?

Radiation shielding is simply a barrier placed between a source of radiation and the area or person that needs to be protected. The purpose of radiation shielding is to limit, control, or modify the radiation exposure rate at a set point.

Shielding is based on attenuation or the gradual reduction in the intensity of energy through a specific medium. X-ray radiation that passes through certain materials decrease and are absorbed, thereby reducing the exposure to the other side of the barrier.

Without shielding, the public, radiation workers (including dentists and veterinarians), and even nearby office workers could be exposed to levels of radiation outside regulated exposure limits, which can potentially lead to negative health effects. Although it is impossible to completely avoid exposure to radiation, shielding is a critical consideration in any medical facility that greatly reduces unnecessary exposure.

Shielding Materials

There are several different materials that provide protection from penetrating radiation. Concrete, water, special plastic shields, air stops, and lead are all barriers that stop different types of rays and particles, reducing the overall dose a person receives.

In medical environments, the most common shielding materials used include lead, lead-free shielding, and lead composites.

Lead

Lead is one of the most used and most effective shielding materials. It is a highly dense material with a high atomic number and a high number of electrons which make it ideal for shielding in most medical radiation environments. This is because the type and energy of radiation in a medical environment that passes through lead are absorbed or scattered by the electrons present in the material.

Vet team wearing shielding garments during exam

Lead is also cheap and easy to process. It can be mixed with other materials like glass, or binders like vinyl, which allows it to be used as construction materials in X-ray rooms or worn as shielding garments.

Lead-Free Shielding

Technological advances have allowed for the creation of non-toxic, lead-free shielding materials as well. Other attenuating materials such as antimony (Sb), tungsten (W), and tin (Sn) are used in place of lead and combined with additives and binders to create wearable protective garments or materials. They offer equal protection from scatter radiation.

Lead-free shielding has several benefits, including being both recyclable and non-toxic. Lead-free shielding materials can also be lighter which makes them easier for personnel to wear during longer procedures.  

Lead Composite

Lead composite shielding is a long-lasting mixture of lead and lighter materials that attenuate radiation just as successfully as traditional lead shielding barriers.

Because of lead’s weight, it can be cumbersome to use and wear for long periods of time, limiting the efficacy of a radiation worker. Lead composites solve this problem. They are made with blends of tin, vinyl, and rubber and create a shielding barrier that can be up to 25% lighter than traditional shielding without sacrificing their ability to block penetrating radiation.

Shielding and Scatter Radiation

In some diagnostic X-ray procedures, medical personnel such as operators, radiologists, and technologists are required to remain in the room with the patient. This proximity frequently exposes them to something called scatter radiation or radiation that bounces off a patient’s body during a procedure.

To limit this exposure, some medical personnel are required to wear frontal or full wrap-around style lead aprons, thyroid shields, and lead glasses/gloves. These protective garments can attenuate roughly 93% of photons at typically scattered energies.

Lead apron and thyroid collar on hangar

Shielding Products and Design

There are several different ways radiation shielding can be applied or designed to protect healthcare workers.

Room Shielding

Shielding may be required in the floor, ceiling, doors, or any wall of any X-ray or radioactive material use room.  Shielding is used to protect workers, patients, or the public that may be in the adjacent areas/rooms.

During a room’s construction, special shielding materials are installed where their need has been determined. These materials can include lead-lined windows and doors, lead-lined drywall or plywood, lead sheets for floors and ceilings, pipe shielding, and more.

X-ray room shielding requirements vary from state to state. It is important to consult with a qualified expert familiar with these regulations as well as work with an architect experienced in constructing X-ray suites before building a new room.

Leaded Glass and Curtains

In some cases, it isn’t possible for a facility to build shielding into the physical structure of a building.

Leaded glass barriers are a barrier used by techs and doctors which allow them to safely view a patient during an imaging procedure. This type of glass is ideal for radiation-producing equipment in the 80-300 kV range thanks to its high lead content.

Lead curtains are also used to shield radiation workers, particularly in large animal hospitals or operating rooms. These curtains are leaded rubber or vinyl sheets that are ideal for protection against low-level or secondary radiation. They make for room-saving partitions that can be open or closed as needed and typically offer protection from 0.5mm to 2.00mm lead equivalency.

Mobile Shielding Barriers

In some cases, additional barriers are needed to protect doctors and techs during radiology, nuclear medicine, cath lab, or diagnostic imaging procedure. These barriers are lead-lined partitions on wheels, often with a protected window to allow for patient observation.

Mobile radiation barriers come in a variety of shapes, sizes, and lead equivalencies. They are ideal for maintaining flexibility and ease of movement in a procedure room while successfully minimizing the scattered radiation dose to workers in the room.

Versant Physics Shielding Services

Understanding the detailed shielding requirements for your state or facility can be a time-consuming challenge. If executed incorrectly, there can be serious consequences to the health and safety of radiation workers, patients, and building staff as well as potential regulatory compliance fines.

That’s why it is important to have a radiation safety consultant like Versant Physics on your side. Whether you’re constructing a new X-ray room, remodeling or repairing an existing shielding setup, or looking to upgrade your current shielding equipment, our team of expert health and medical physicists can assist.

We provide radiation shielding calculations, evaluation, and design for facilities of all kinds, including hospitals, clinics, dentist offices, chiropractor offices, and veterinary clinics. Our range of expertise includes:

  • Radiography
  • Fluoroscopy
  • Computed Tomography (CT)
  • Nuclear Medicine/PET
  • Mammography
  • Dental/Veterinary X-ray

Not sure what materials or type of shielding is right for your facility? Contact our regulatory experts for a free 30-minute consultation.

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