A compensator attenuates the beam based on the irregular contour of the patient. Like the physical wedge, it is placed in the treatment head of the machine, but functions in a similar way to bolus in evening out isodose lines at depth within the patient.Also asked, what are wedges 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.
Secondly, what is compensator based IMRT? Customized compensators are shaped to attenuate the open-field photon fluence such that the transmitted fluence map is as designed by the dose optimization algorithm. The obvious advantage of this IMRT delivery method is simplicity.
People also ask, 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 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 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 factor?
I am a bit confused in definition of 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. Podgorsak defines the ratio usually at Dmax.What is 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 DMAX radiotherapy?
When a radiation beam interacts with tissue, a certain depth of tissue is required before we see the maximum amount of radiation (maximum dose or dmax). The dose at dmax is defined as 100% and then the radiation dose decreases as the depth increases, the energy being absorbed within the tissue.What is isodose curve?
ISODOSE CURVES DEFINITION: Isodose curves are the lines joining the points of equal Percentage Depth Dose (PDD). The curves are usually drawn at regular intervals of absorbed dose and expressed as a percentage of the dose at a reference point.What is SSD in radiation therapy?
Modern photon beam radiotherapy is carried out with a variety of beam energies and field sizes under one of two set-up conventions: a constant source to surface distance (SSD) for all beams or an isocentric set-up with a constant source to axis distance (SAD).What is beam modification?
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.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.Does Aetna cover radiation treatments?
Aetna considers radiation therapy medically necessary for preventing heterotopic ossification in persons identified as being at high risk (previous heterotopic ossification, ankylosing spondylitis, diffuse idiopathic skeletal hyperostosis or spinal stenosis, unlimited hip motion preoperatively, and head injury). 
