The widespread adoption of tungsten alloy collimators in the medical field stems from their comprehensive advantages in material properties for radiation shielding and structural design.
As a core component of radiation control, collimators need to achieve directional control of the radiation beam while minimizing the scattering effects and radiation impact of rays on surrounding tissues.
Tungsten alloy, with tungsten as the main matrix and alloyed with elements such as nickel, iron or copper, has a high atomic number and dense microstructure, making its attenuation efficiency for X-rays, γ-rays and particle beams significantly superior to traditional materials, thus becoming the preferred choice in medical equipment.
The radiation shielding performance of tungsten alloy is its core value.
In medical imaging and radiotherapy, collimators need to block rays deviating from the path to avoid unnecessary exposure.
The high-density characteristic of tungsten alloy allows efficient absorption in thinner thicknesses; non-parallel rays undergo photoelectric effect or Compton scattering with tungsten atoms and attenuate rapidly, thereby ensuring beam purity as much as possible.
The material also has good thermal stability and mechanical strength, and will not undergo significant deformation or thermal damage even in high-energy radiation environments, which is important for the long-term stable operation of linear accelerators or CT equipment.
In addition, tungsten alloy has good processability and can be made into complex geometric shapes through powder metallurgy, such as independent leaves of multi-leaf collimators or pinhole arrays, to meet the fine resolution needs of SPECT imaging.
Compared with lead, the advantages of tungsten alloy in medical collimators are particularly prominent.
Lead, as a traditional shielding material, was once widely used in radiation protection, but its lower density means that a larger volume or thickness is required to achieve equivalent shielding effects, which increases the overall weight and volume of the equipment.
The toxicity of lead is another major defect; during production, use and disposal, it may release harmful substances, posing health risks to medical staff and patients.
In contrast, tungsten alloy is non-toxic and environmentally friendly, with simpler waste disposal, and its shielding efficiency is stronger, providing thinner collimation components under the same conditions.
Compared with iron materials, the superiority of tungsten alloy lies in the essential difference in shielding capability.
Although iron is cheap and easy to process, its density is much lower than that of tungsten alloy, and its attenuation coefficient for high-energy rays is low, making it difficult to efficiently block penetrating photons or particles in medical radiation.
In CT or nuclear medicine equipment, using iron collimators requires significantly increased thickness to compensate for insufficient shielding, which not only enlarges the equipment size but may also introduce magnetic interference, affecting imaging quality or treatment accuracy.
The corrosion sensitivity of iron is also a problem; it is prone to rust in humid or chemically exposed environments, reducing component lifespan.
Tungsten alloy is corrosion-resistant and high-temperature resistant, maintaining structural integrity under harsh medical conditions and avoiding frequent maintenance.
