Monitoring of Patient Movement During Radiotherapy May Get Easier
Research from Washington University School of Medicine in St. Louis has found using new mmWave technology to be a great asset to perform precise monitoring of patient motion in real-time during radiotherapy treatments. The mmWave technology can monitor displacements with .1mm to 1 mm accuracy at low cost using a simple and easy to use device. Imaging with millimeter waves can overcome obstacles of current techniques like the optical tracking of a patient’s skin surface or CT scanning. This new device can also monitor breathing and cardiac motion that may, in time, replace respirometers or other breathing monitoring devices. To read more about the research and the outcome of mmWave technology, you can read this article for more information.
Beams Used in Radiation Therapy
Photons
The majority of radiation therapy machines use ionizing photon beams since they can reach tumors deep in the body. Photons are also used in x-rays, although they consume a much lower dose of the particle in comparison. The radiation that is delivered during photon treatment will damage the DNA of tumors and healthy cells alike. Radiation therapists aim to maximize the dose targeting the tumor while minimizing the radiation to nearby healthy tissues by creating different paths with multiple fields. To avoid overexposure to healthy cells, the treatment is generally given in stages over repeated scheduled sessions so that the healthy cells have time to repair.Protons
Charged particle radiotherapy is an alternative method of radiotherapy that uses beams of protons or other positively charged particles such as helium, carbon, or other ions that are not photons. These types of beams can also reach tumors deep inside the body, but they perform differently than photons as they do not scatter radiation on their path and will stop once they reach the targeted tumor. Due to the physical characteristics of charged particles, it may be possible to cover the tumor area with only one radiation field, creating an advantage over the use of photons to spare more healthy tissues and cells. Clinical trials are continuing to compare the usage of these two energy types. There are cancer centers that are beginning to use proton beams in radiation therapy, but they have higher costs and require a larger space to fit the increased size of the equipment.Electrons
Particles with a negative charge are electrons. Electron beam radiation therapy is designed to treat cancers like lymphoma and other tumors near the surface since these electrons do not go deep into the body. These therapy options can be done in two different ways:- Spot treatment – This method is used for one or more cancerous spots on the body that needs treatment.
- Total Skin Electron Beam Therapy (TSEB) – This method is used when the entire surface of the skin needs to be treated. Other treatments called compensation treatments can be part of the treatment plan to guarantee that every area of the skin receives the proper dose required.
World Cancer Day Brings Discussions for More Affordable Radiotherapy Treatment Options
In celebration of World Cancer Day on February 4th, director of IAEA General Rafael Mariano Grossi raised awareness about radiotherapy and how widely used the treatments are throughout the world. He brought to light the fact that 1/3 of lower-to-middle-income countries do not have access to any radiotherapy treatments. A total of 28 countries in Africa do not have a single radiotherapy unit, which makes a cancer diagnosis almost a death sentence for many. It is estimated that 300,000 women die from cervical cancer each year, which needs to stop as this form of cancer can typically be treated and cured in developed countries. The IAEA continues to spread awareness and will establish nuclear and radiation medicine services and provide training to medical professionals to help change these statistics. To learn more, read this article.
Solutions for Cooling Systems of a LINAC
How A LINAC Works
A medical linear accelerator (LINAC) produces and delivers a radiation beam using high energy x-rays or electrons to a targeted area to destroy cancer cells while carefully not damaging the surrounding normal and healthy tissues nearby. The medical equipment accelerates electrons in part of the accelerator called the waveguide and then allows the electrons to collide with a heavy metal target to create the high-energy x-rays. The radiation beams are shaped as they exit the machine to conform to the shape of the patient’s tumor. The patient lies on a movable treatment couch and the lasers are designed to be sure that the patient is in the correct position. The couch can move in a variety of directions along with the gantry – the part of the accelerator in which the radiation beam comes from.Cooling System Needs
When using a LINAC during IMRT (intensity-modulated radiation therapy), the thermal consistency is necessary to maintain beam energy and stability. All the parts inside the equipment such as the tungsten target, waveguide, acceleration chamber, and the magnets need accurate thermal control to eliminate heat buildup and to allow the temperatures to remain the same for optimal usage for operation. Some of the parts within the machine, like the waveguide and filament material, require temperatures within .5 degrees Celsius. The solution to this is to install a liquid cooling system as the best option. In an IMRT system, the cooling path can be complicated. The water starts by cooling the charging drawer and oil pump. It then leads to the liquid cooling system that will decrease the temperature of the entire system, including the linear accelerator.Types of Liquid Cooling
Liquid cooling systems are ideal for temperature control and stabilizing. They are designed to remove large amounts of heat that is generated in a densely packed electronic environment of a linear accelerator. It may cause concern that liquid coolant is so near all these electrical products but if the cooling system is designed and assembled correctly, there should be no issues. A few reasons these systems are more beneficial opposed to air-based heat exchangers is the ability to provide faster cooling, runs more quietly, and is more reliable with less downtime. Three options for cooling systems are:- Liquid – Air Heat Transfer Configuration – a high-pressure pump that recirculates the liquid coolant and an air heat exchanger to remove heat in the liquid system
- Liquid – Liquid Configuration – the pump recirculates the coolant and the facility water is used for a liquid heat exchanger to remove heat from the higher temperature side
- Compressor – Based Chiller System – the pump recirculates coolant that is chilled to well below standard temperature
New Forms of Flash Radiotherapy Being Researched
Treating cancer can be a long and tedious process with multiple procedures that need to be performed using radiation equipment such as linear accelerators. To become cancer-free, what if this process could be easier? An emerging form of treatment called FLASH radiation therapy treats a cancer patient with a similar amount of radiation normally given over weeks, dispensed at once, within a second of time. FLASH radiotherapy is found to be as effective in killing cancer cells without the continual exposure of radiation to healthy tissue. Researchers at Pennsylvania University are also studying that by changing the type of particle used in the linear accelerator from electrons to protons the treatment will penetrate deeper into the body, essentially making FLASH radiotherapy more effective in treating cancerous tumors. To read more about this new research, click here.
New Partnership for ViewRay In the Works
Plans for the partnership for radiation therapy company ViewRay with Medtronic and Elekta are in the works. News of the new joint decision has already increased ViewRay shares up 37% in the after-hours trading. The agreement is however contingent upon ViewRay raising $75 million in equity capital, so the agreement is non-binding at the time. The collaboration is hopeful for ViewRay to work with Elekta and run clinical studies to research MR-guided radiation therapy. The details of the agreement made with Medtronic are less available in this stage, but analysts believe the investments from Medtronic’s partnership show “strong signs”. To read more on this new partnership with these companies read here.