What are the machines used for radiation therapy?

(i) Machines used for external irradiation X-ray therapy machines The quality of X-rays produced by an X-ray therapy machine is related to the voltage. The X-rays produced have a range of energies from zero to maximum. The low-energy portion of the X-rays has no therapeutic value. The voltage can be adjusted to vary the energy when used for contact, superficial and deep treatment. Deep X-ray machines are mainly used for radiation therapy of superficial lesions. 60Co therapeutic machine When the radionuclide 60Co is used for treatment, 60Co emits two kinds of γ-rays in the process of decay. γ-rays are more penetrating than the deep X-rays, the skin dose is low, the skin reaction is light, the dose of the deep tissues is high, and the bone damage is lower than that of the X-rays. 60Co therapeutic machine is cheap, and it is easy to maintain. However, there are problems of larger projection penumbra and regular replacement of the 60Co source.60Co therapy machine is one of the most commonly used equipment for external irradiation. Medical gas pedal gas pedal types are more, commonly used in radiation therapy gas pedal linear gas pedal, electronic induction gas pedal, electronic cyclotron. Currently the most commonly used gas pedal is the linear gas pedal. Linear gas pedal has a simple X-ray and electron line (also called beta line), can rely on the adjustment of the energy of the ray to adjust the depth of X-ray, electron line shot human tissue. And 60Co treatment machine and deep X-ray treatment machine energy is fixed. Linear gas pedal in recent years has gradually dominated the clinical radiation therapy. Compared with 60Co therapy machine, linear gas pedal produces high-energy X-rays can replace 60Co, and easy to operate, high dose rate, energy can be adjusted to overcome the 60Co therapy machine penumbra, short half-life and radiation protection shortcomings. In the clinic, according to the depth of the tumor location, it can choose the rays with appropriate energy and penetration depth. (ii) Machines used for proximity irradiation Machines used for proximity irradiation are also called rear-loaded treatment machines. This kind of treatment machine is to put the radioactive source on the surface of the tumor or in the tumor tissue for irradiation, commonly used in the treatment of intracavitary tumors or larger solid tumors.