Beam's eye view (abbreviated BEV) is an imaging technique used in
radiation therapy
Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radi ...
for quality assurance and planning of
external beam radiotherapy
External beam radiotherapy (EBRT) is the most common form of radiotherapy (radiation therapy). The patient sits or lies on a couch and an external source of ionizing radiation is pointed at a particular part of the body. In contrast to brachyt ...
(EBRT). These are primarily used to ensure that the relative orientation of the patient and the treatment machine are correct. The BEV image will typically include the images of the patient's anatomy and the beam modifiers, such as jaws or multi-leaf collimators (MLCs).
Generation of Beam's Eye Views
* Physical Construction:
** BEV's can be generated by exposing a high energy film (similar to
photographic film) or an Electronic Portal Imaging Device (EPID) with the treatment beam itself after it passes through the patient and any beam modifiers (such as blocks). Although this type of image is an excellent indication of the basic quality of the treatment plan, the quality of film images can be poor.
** A BEV can be created using a radiation therapy simulator which mimics the treatment geometry (couch angle, gantry angle, etc.) using an
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
source instead of the higher energy treatment source. The jaws and blocks can be imaged on the same film as the patient's landmarks.
* Artificial Reconstruction: The BEV can be created using a
Digitally Reconstructed Radiograph (or DRR) that is created from a
computed tomography (or
CT) data set. This image would contain the same treatment plan information, but the patient image is reconstructed from the
CT image data using a physics model.
References
* Faiz Kahn and Roger Potish (Eds.) (1998).''Treatment Planning in Radiation Oncology''. Williams & Wilkins. .
* Jacob Van Dyk (Ed.) (1999). ''The Modern Technology of Radiation Oncology''. Medical Physics Publishing. .
* Ross I. Berbeco (Ed.) (2018). ''Beam's Eye View Imaging in Radiation Oncology''. CRC Press. {{ISBN, 978-1-4987-3634-3.
* Louis Lemieux, Roger Jagoe, David R. Fish, Neil D. Kitchen, David G. Thomas, ''A patient-to-computed-tomography image registration method based on digitally reconstructed radiographs.'' Med. Phys. 21(11), 1749–1760 (1994). https://doi.org/10.1118/1.597276
Radiobiology
Medical physics