Table of Contents
Why is aluminum used for Xray beam filtration?
The purpose of the aluminum filter is to remove the low-energy, long-wavelength, least penetrating x-rays from the beam. X-ray machines operating at 70 kVp or greater must have aluminum filtration of 2.5 mm.
What is beam filtration?
Filtration, the process of attenuating and hardening an x-ray beam, is traditionally quantified in units of mm Al (aluminum) or the thickness of an aluminum filter that would have the same effect on the beam. The filtration provided by the x-ray tube housing assembly itself is termed the inherent filtration.
What is a Thoraeus filter?
The Thoraeus filter is a combination filter containing plates of tin, copper, and aluminum and have been designed to increase the resulting half-value layer of the orthovoltage beams without reducing the beam intensity to unacceptably low values.
What is a lead collimator used for?
Collimators (beam limiting devices) are used in linear accelerators used for radiotherapy treatments. They help to shape the beam of radiation emerging from the machine and can limit the maximum field size of a beam.
What material absorbs xrays?
Summary: Research shows lightweight composite metal foams are effective at blocking X-rays, gamma rays and neutron radiation, and are capable of absorbing the energy of high impact collisions. The finding means metal foams hold promise for use in nuclear safety, space exploration and medical technology applications.
What is used to direct the Xray beam?
lead plate with a hole in the middle, is fitted directly over the opening of the machine housing where the x-ray beam exits the tubehead. or cone, appears as an extension of the x-ray tube head and is used to direct the x-ray beam.
How does filtration affect the primary beam?
Filtration reduces x-ray intensity, but not the maximum energy of the x-ray beam spectrum. The change in the shape of the beam spectrum with filtration is referred to as beam hardening. This is due to the loss of lower energy photons from a polychromatic beam.
What is Xray beam?
The x-ray beam is polyenergetic (many energies) and consists of a wide range of energies known as the x-ray emission spectrum. The lowest energies are always approximately 15 to 20 keV, and the highest energies are always equal to the kVp set on the control panel.
What are flattening filters made of?
In the most clinical linac, the materials which formed the flattening filters are aluminium, Iron, copper, tungsten, or a mixture of these components, that are all characterised by a high Z material. What is more, these materials are specific to each particular beam energy.
What is K edge effect?
The K-absorption edge (K-edge) refers to the abrupt increase in the photoelectric absorption of x-ray photons observed at an energy level just beyond the binding energy of the k-shell electrons of the absorbing atom. K-shell binding energies are specific to each element.
How will filtration affect the primary beam?
What are collimators made of?
They are made of lead shutters which completely absorb the photons, and thus reduce the patient dose as well as focus the radiation accordingly to the area of interest. They allow different projections of x-ray fields.