The Linear Accelerator: What is It and How Does It Work

A linear accelerator (LINAC) is a machine most often used for delivering external radiation therapy to those dealing with cancer. The device uses a variety of methods to customize high energy x-rays to mirror an individual tumor’s shape so that radiation can be administered as accurately as possible. 

LINAC devices efficiently target and destroy cancer cells while protecting surrounding healthy tissue, making this type of treatment more effective with fewer side effects. 

How exactly does this equipment work?

The linear accelerator is used to treat solid tumors in all areas of the body. A radiation oncologist will run several diagnostic measures to determine the size, shape, and location of the tumor. Afterward, the oncologist will determine what level of radiation dosage will be used. The media radiation physicist and dosimetrist will evaluate how to deliver the prescribed amount of radiation and calculate the amount of time it will take to administer over time. 

After the preliminary diagnostics for administration are prescribed, the LINAC is adjusted and customized to fit the shape of the radiation beam to conform to the individual tumor properties. Using microwave technology similar to that used in radar, the LINAC’s “waveguide,” then accelerates electrons and sends them to collide with a heavy metal target to produce high-energy x-rays. As the rays exit the machine, they are shaped to match the tumor’s outlines and directed towards the tumor area.

Specific protocols and safety measures are conducted to ensure that the beam cannot exceed the prescribed dose or travel outside of the pre-determined bounds that could damage healthy skin. 

During the treatment, you will lie on a moveable couch or seat beneath a part of the linear accelerator called a gantry. Your radiation therapist will use lasers to ensure that your treatment area is administered precisely. Your radiation therapist will also assist in helping your body to remain positioned for optimum beam exposure to the right areas. 

Radiation can be focused on any area of the body from any angle by rotating the gantry and moving the treatment couch. During treatment, you will be continuously monitored by the technologist for position, accuracy, and comfort. 

Reference Link: https://www.adventisthealth.org/cancer-center/our-technology/varian-linear-accelerator/

American College of Radiology Issues New Guidelines for Non-Urgent Treatments

On May 6th, 2020, the American College of Radiology (ARC) released new guidelines that can help radiology practices resume non-urgent treatments safely. Treatments that are considered non-urgent are mammograms, oncologic and orthopedic imaging, and image-guided biopsies. Most of these treatments do not include radiation therapy that often involves the use of Linear Accelerators and CT scanners

As Coronavirus cases continue to drop in most areas, radiology practices are starting to resume non-urgent care practices to patients. “Radiology practices largely followed the World Health Organization, Centers for Disease Control and Prevention, and SCP guidance to postpone non-urgent care. While local conditions prevent a single prescriptive strategy to resume such care, general principles can apply in most settings…” said American College of Radiology Commission on Quality and Safety Chair, Jacqueline A. Bello, M.D., FACR. 

Read more about the ACR guidelines here

Recent Developments in Artificial Intelligence and Radiation Therapy

“AI (artificial intelligence) can help treatment planners and dosimetrists by saving a lot of time doing simpler and more repetitive tasks…,” explained Steve Jiang, Ph.D., director of the medical artificial intelligence and automation lab of the Dept. of Radiation Oncology, University of Texas Southwestern. 

For those unfamiliar with AI, we are referring to computer or machine intelligence systems that can perform tasks that usually require human intelligence, such as visual perception, speech recognition, decision-making abilities. 

Discussions about how AI will impact humanity have been occurring for many years in many industries; however, AI has been making headway into the radiation therapy and oncology fields within the past few years. 

Two such companies making the technological leap in AI for radiation oncology and treatment planning are Varian and RaySearch – both have developed machine-learning technologies to automate treatment plans.

“The fully automated system takes in the patient imaging and the target defined by the physician, and out on the other end comes a fully deliverable therapy plan,” said Kevin Moore, Ph.D., DABR, deputy director of medical physics and associate professor, University of California San Diego.

Dr. Moore said that “The comparisons were very good,” about tests that were made when SCSD began using the software in tandem with traditional treatment planning. After a human plan was developed, they ran the AI, and it only took 5-20 minutes to complete depending on the complexity of the plan. UCSD has now treated well over 1,000 patients with its AI-assisted planning. 

RaySearch has incorporated machine learning clinically since 2019. The system is trained to take the treatment planning computed tomography (CT) scans and automatically segment the anatomy and auto-contour to help speed the planning process. 

“The automated treatment planning system works by training the algorithm with curated sets of similar treatment plans, and it is able to detect the patients who are most similar to a novel patient and create a new treatment plan…,” explained Leigh Conroy, Ph.D., physics resident, at Princess Margaret Cancer Center, who has been working on the AI implementation. 

RaySearch is developing several other machine learning applications, including target volume estimation and large-scale data extraction and analysis.

Other highlights of AI technologies are adaptive AI-driven onboarding planning within the radiotherapy system, auto contouring for treatment plans, and creating MRI-derived CT scans for planning. To read more on these exciting technologies, read the full article here.  

RefleXion Receives Clearance from FDA for New X1 Machine

A significant stepping stone in radiotherapy occurred with the announcement by the therapeutic oncology company, RefleXion Medical. RefleXion Medical received clearance from the U.S. Food and Drug Administration (FDA) for three types of therapy; stereotactic body radiotherapy (SBRT), stereotactic radiosurgery (SRS), and intensity-modulated radiotherapy (IMRT). The groundbreaking new technology within the X1 machine will allow for more precise tumor location capabilities that can combine high-quality CT imaging. Within the X1 device, a linear accelerator offers technology that can rotate 60 times faster than standard linear devices. In this article, the CEO of RefleXion Medical is hoping that the X1 machine will treat not only the early stages of cancer but also offer thorough treatment solutions for those suffering from the most advanced stages. The transition of this company from a research-level, to now a commercial entity, has been a 10-year process. The company comes full circle by offering a new form of treatment with biology-guided radiotherapy (BgRT) into the market. 

MRIdian Machines Create Precise Radiotherapy Methods

More than half of cancer patients that receive a diagnosis are most likely to be treated with a form of radiotherapy. Radiotherapy is a treatment that provides a high dose of radiation using a piece of equipment such as a linear accelerator and is aimed at a given area to eliminate cancer cells. Today’s technology has been very successful with these methods of cancer treatment. Still, even with precise planning, radiotherapy has many obstacles to overcome. Simple internal movements within the body such as breathing, bladder filling, digestion, or tensing up can impact the tumor movement up to half an inch, which may cause radiation to damage surrounding healthy cells and tissues. Engineers have developed a type of magnetic resonance linear accelerator (MR Linac) to combat these movement issues with live, detailed images of the tumor with higher accuracy. Read More on how this equipment can be utilized for precise treatments on patients.

Scientist Search for the Next Elements to Add to Periodic Table

Nuclear physicist, Kosuke Morita at Japan’s Kyushu University is on the verge of creating the next new element for the periodic table. Morita and his team have successfully synthesized a new element to the periodic table, making it number 113. There is now a total of 118 known elements, and the race for number 119 is on. In nature, there are only 92 protons in a nucleus of an atom, but through research and experimentation, it has been possible to synthesize atoms with more in a lab. Element 119 is still a hypothetical element that would be the seventh alkali metal named ununennium. Morita’s team plans to conduct experiments using two types of particle accelerators, including the cyclotron beam and a linear accelerator. To read more information on how his team was successful in creation on element 113 and future plans for element 119, read here.  

Particle Accelerator in New York To Probe Protons and Neutrons

For the first time in decades, the United States will have its first new particle collider. The Department of Energy announced earlier this year that the new location of this machine will be at Brookhaven National Laboratory in Upton, New York. The research will be done with the instrument to study the dynamic makeup of protons and neutrons. The new particle collider is a strong electron microscope that shoots electrons at protons and neutrons in order to measure them. The use of these accelerators shows great promise for the future in the fields of nuclear medicine as well as quantum information technologies. The design process will, however, not be finalized until 2024, and then it will take about another six years for construction and start up to occur. To read more on the new particle collider in this article, click here.

New Micro Particle Accelerator Chip

Scientists at Stanford Linear Accelerator Center (SLAC) have introduced a new technological milestone for a prototype nanoscale particle accelerator. The new gadget gives promise for cancer treatments and will provide more scientific access to the functions of traditional particle accelerators, which are two-mile-long devices. A team of researchers believes that the technology offered by these large machines can be scaled down in size for accessible use in labs. However, the micro single chip is much less powerful than the larger Linac machines they mimic. In theory, they can still accelerate electrons up to 94% of the speed of light in order to create a particle flow strong enough for medical use and research. The miniature creation is still years away from use in radiotherapy. The seemingly simple concept of scaling down the design of large Linac systems is easier said than done, but it shows promise for the future and gives evidence of what potential these microchips have. To read more on this new finding click here

Should I Replace or Upgrade My LINAC System?


Having a shiny LINAC system in your clinic entitles you to benefits and services other clinics lacking this technology do not. Such a system is imperative when dealing with minute cancer situations and can not only give the medical staff an edge but also give patients a guarantee of quality others cannot. That said, a proper LINAC system is, quite obviously, not a cheap system to not only implement initially but maintain over time. At one point a clinician or technician may decide the time has come to upgrade to what’s best out there, but such a decision is not so black and white. This article should briefly outline why so.

What Do You Have?

When making the decision to upgrade, you have to look at what you have already implemented. What you have may actually be satisfactory despite being old. LINAC systems themselves are as pricy as one may expect but are also modifiable with different parts that make up the whole. Linear accelerators can be classified as defined by their part status. Essentially, your linear accelerator can be classified from older and lacking upgrades, through newer but lacking and older and possessing upgrades, to newer and possessing upgrades. Where your system lies on the spectrum indicates whether or not making upgrades is worth the cost when considering the competency.

What is Your Budget?

Depending on the overall budget and success of your clinic you may find it smarter to simply upgrade certain parts on your older LINAC system. If money is no object you can naturally swap out your system – even if it’s new – for a newer, more modern and up-to-date model. Having an infinite source of funds is most likely not the case for most clinics, so you must take budget into effect and decide if your system is old enough to really warrant a true upgrade. Remember, upgrading certain parts of your system will always be cheaper than an outright replacement, and going with used upgrades is still a viable and more cost-effective option.

Do You Have Time?

When replacing a LINAC system completely, time is of great importance. Upgrading certain parts on a system can take hours and can be done overnight, but swapping out an entire system can take much, much longer. Are you able to survive with such an important machine out of the office for so long? If your system isn’t too old and has competent upgrades, then it can be hard to justify that absence. Any experienced clinician understands his or her own office enough to know whether or not that absence is detrimental to overall clinic success.

As an independent LINAC service company, Acceletronics is dedicated to delivering the best equipment performance and services for linear accelerators and CT scanners across all major brands and models, as well as new and refurbished LINAC systems for sale.  More information can be found online at https://www.acceletronics.com/.