Tag: shielding

01 Jun 2022
diagnostic imaging procedure

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 Apr 2022
Nurse standing behind radiation shielding

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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Forum Article "Radiopharmaceutical Extravasation: Pragmatic Radiation Protection" published ahead of print

An article written by Versant team members Dr. Darrell R. Fisher, Ph.D. and Misty Liverett, M.S., CNMT was recently published ahead of print in Health Physics. The article provides an unbiased, scientific assessment of pragmatic and reasonable health physics actions that should be taken in response to inadvertent extravasation events. Click the link below to view the article.

Permits

THE PERMISSION SYSTEM FOR INVENTORY TRACKING, MACHINE MANAGEMENT & EQUIPMENT CATALOG MODULES

Permit Profile

Each permit has a dedicated profile of information that includes authorized personnel, radioactive material, machines, and devices. Permit conditions, completed audits, and forms are also found on this profile.

Authorized Condition Database

Create and view authorized conditions included on permits. Previously created authorized conditions are listed with their code, category, and description.

Permit Enforcement

Information specified on a permit not only serves as a record of that permit, but also controls what can be added to other modules. The location, owner and type of radioactive materials, machines, and equipment can be enforced by permits.

Permit Audits

Perform permit audits, mail the results to relevant personnel, and track responses to non-compliances.