DEFINITION: • Beam Modification Defined as desirable modification in the spatial distribution of radiation - within the patient - by insertion of any material in the beam path. Flattening: Where the spatial distribution of the natural beam is altered by reducing the central exposure rate relative to the peripheral.Herein, why are wedges used in radiotherapy?
In radiation therapy, wedge filters are commonly used to improve dose uniformity toward the target volume [2]. A physical wedge is usually constructed from a high-density material, such as lead or steel, which attenuates the beam progressively across the entire field.
One may also ask, why are compensators used in radiotherapy? Breast cancer is a challenging case in radiation therapy because of the breast's irregular contour and inhomogeneous tissue density. Use of compensators in radiotherapy solves the problem of irregular dose distribution. The system described here is now routinely used in this clinic on all breast cancer patients.
People also ask, what are wedges and compensators radiotherapy?
In radiation oncology, wedge filters are commonly used to improve the dose uniformity in the target volume. They can be used as missing tissue compensators or wedge pairs to alter the shape of isodose curves so that two beams can be angled with a small hinge angle at a target volume without creating a hotspot.
What is a wedge filter?
wedge filter. A filter used in radiography and radiation therapy to vary the intensity of the x-ray beam. This compensates for differences in the thicknesses of the parts being exposed to radiation. See also: filter.
What is a dynamic wedge?
Modern medical accelerators are usually equipped with a dynamic wedge option. It is a form of dose-rate modulation which makes use of the dynamic movement pairs of collimator jaws. Dynamic wedges may replace physical wedges but their use requires more complex dosimetry and quality control procedures.What is wedge angle?
The wedge angle is defined as the angle through which an isodose curve at given depth in water (usually 10 cm) is tilted at the central beam axis underthe condition of normal beam incidence. Open and wedge beam isodoses curves.What is a wedge factor?
KHAN defines it as the ratio of the doses with and without the wedge, in a phantom at a suitable depth beyond the depth of maximum dose.What is tissue compensator?
ABSTRACT. A radiation beam incident on an irregular or sloping surface produces the non-uniformity of absorbed dose. The use of a tissue compensator can partially correct this dose inhomogeneity. The tissue compensator is designed based on the patient's three dimensional contour.What is a trough filter?
Trough Filter Applications. -Trough filter used on parts that are thin (less dense) on the edges and thick (more dense) in the center.What are compensating filters used for?
The filters are used to limit the primary beam at an anatomical region during a specific examination that requires fine radiographic detail at both the 'denser' and 'less dense' regions, e.g. a horizontal beam lateral hip requiring detail at both the proximal and distal portion of the image.What is inherent filtration?
Inherent filtration refers to a permanently implemented filter in the useful beam. Inherent filtration includes the window of the x-ray tube and any permanent enclosure for the tube or source. Filters partially absorb or attenuate the x-ray beam to prevent radiation overexposure.What is a compensating filter?
A simple or complex system of placing a discretionary metal filter (usually aluminum, usually wedge-shaped) in front of the collimator in order to attenuate (reduce) a portion of the primary beam so as to compensate for varying body part thicknesses in the same field of view.What is filtration in radiology?
Filters in Radiography. At x-ray energies, filters consist of material placed in the useful beam to absorb, preferentially, radiation based on energy level or to modify the spatial distribution of the beam. Filtration is required to absorb the lower-energy x-ray photons emitted by the tube before they reach the target. 
