Search results
Results from the WOW.Com Content Network
Research in this area has focused on the three most common sources of radiation used for these applications, including gamma, electron beam, and x-ray radiation. [17] The mechanisms of radiation damage are different for polymers and metals, since dislocations and grain boundaries do not have real significance in a polymer.
Electron beam therapy is used in the treatment of superficial tumors like cancer of skin regions, or total skin (e.g. mycosis fungoides), diseases of the limbs (e.g. melanoma and lymphoma), nodal irradiation, and it may also be used to boost the radiation dose to the surgical bed after mastectomy or lumpectomy.
Electron-beam processing involves irradiation (treatment) of products using a high-energy electron-beam accelerator. Electron-beam accelerators utilize an on-off technology, with a common design being similar to that of a cathode ray television. Electron-beam processing is used in industry primarily for three product modifications:
In water, broad electron beams, as is the case in homogeneous surface contamination of skin, have d 80 about E/3 cm and R p about E/2 cm, where E is the beta particle energy in MeV. [ 24 ] The penetration depth of lower-energy beta in water (and soft tissues) is about 2 mm/MeV.
External beam radiation therapy (EBRT) is a form of radiotherapy that utilizes a high-energy collimated beam of ionizing radiation, from a source outside the body, to target and kill cancer cells. The radiotherapy beam is composed of particles, which are focussed in a particular direction of travel using collimators [ 1 ] .
Electron-beam machining is a process in which high-velocity electrons are concentrated into a narrow beam with a very high planar power density. The beam cross-section is then focused and directed toward the work piece, creating heat and vaporizing the material. Electron-beam machining can be used to accurately cut or bore a wide variety of metals.
Because of their reduced ability to repair DNA, cancerous cells are particularly vulnerable to such damage. The figure shows how beams of electrons, X-rays or protons of different energies (expressed in MeV) penetrate human tissue. Electrons have a short range and are therefore only of interest close to the skin (see electron therapy).
Exposure to non-ionizing ultraviolet light is a risk factor for developing skin cancer (especially non-melanoma skin cancers), sunburn, premature aging of skin, and other effects. Despite the possible hazards it is beneficial to humans in the right dosage, since Vitamin D is produced due to the biochemical effects of ultraviolet light.