January 24, 2020 Radparts 0

LINACs are a type of particle accelerator that increases the kinetic energy of a particle that can be used in a variety of different areas such as scientific research or during radiation therapy to remove cancer cells of a patient. As with most medical and lab-related equipment, particle accelerators are negatively affected by thermal changes, especially with an increase of heat. It is of most importance to maintain temperature control of the equipment components to guarantee the integrity, performance, and reliability of the system. A solution that helps maintain temperature control is using a custom liquid cooling system. We will further discuss this option below so you can adequately care for your LINAC equipment.

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:

  1. 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
  2. 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
  3. Compressor – Based Chiller System – the pump recirculates coolant that is chilled to well below standard temperature

Radparts is the world’s largest independent distributor of OEM replacement parts for Linear Accelerators and Radiation Oncology equipment.  Radparts provides high quality, user-friendly, low-cost parts and support for linear accelerators and radiation equipment. More information can be found at https://www.radparts.com/.