News Column

Patent Issued for Radiation Therapy Treatment Plan Improvement through Use of Knowledge Base

July 23, 2014

By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventor Zankowski, Corey (San Jose, CA), filed on September 28, 2011, was published online on July 8, 2014.

The patent's assignee for patent number 8774358 is Varian Medical Systems, Inc. (Palo Alto, CA).

News editors obtained the following quote from the background information supplied by the inventors: "Oncology and Radiotherapy technology continues to evolve, accelerating the expansion of the envelope of possible treatments and best practices associated with those possible treatments. At the same time, the complexity of clinical decisions is increasing non-linearly, resulting in a rapidly widening gap between actual practice and best practices, especially in emerging markets.

"For example, when medical imaging is necessary in the course of radiation therapy, several systems may be used, such as X-ray, magnetic resonance imaging (MRI), computed tomography (CT), and others. When CT or MRI imagery, for example, is used, a series of two-dimensional images are taken from a three-dimensional volume. Here, each two-dimensional image is an image of a cross-sectional 'slice' of the three-dimensional volume. The resulting collection of two-dimensional cross-sectional slices can be combined to create a three dimensional image or reconstruction of the patient's anatomy. This resulting three-dimensional image or three-dimensional reconstruction will contain organs of interest. Those organs of interest include the organ targeted for radiation therapy, as well as other organs that may be at risk of radiation therapy exposure. The portion of the three-dimensional image or reconstruction that contains the organs of interest may be referred to as structures of interest or volumes of interest.

"These one or more structures of interest may be viewed in several ways. A first and simplest way to view the structure(s) of interest would be to merely view the original CT or MRI image slices for the patient, with each slice containing a view of the structure(s) of interest. A second, and more complicated method to view the structure(s) of interest would be to combine the series of two-dimensional cross-sectional slices into a single three-dimensional representation where the structure(s) of interest may be represented as solid, opaque, or translucent, etc., objects that may then be manipulated (e.g., rotated) to allow viewing from multiple angles.

"One purpose of the three-dimensional reconstruction of the structure(s) of interest containing diseased or abnormal tissues or organs is the preparation of a three-dimensional radiation therapy treatment plan. Radiation therapy treatment plans are used during medical procedures that selectively expose precise areas of the body, such as cancerous tumors, to specific doses of radiation to destroy the undesirable tissues. To develop a patient-specific radiation therapy treatment plan, information is extracted from the three-dimensional model to determine perimeters such as organ shape, organ volume, tumor shape, tumor location in the organ, and the position or orientation of several other structures of interest as they relate to the affected organ and any tumor.

"The two-dimensional slices may be individually viewed on a computer screen and with the use of conventional graphics programs, the contours of organs or structures of interest can be traced out by hand. Contours are connected line segments that define the outline of a structure of interest, which may be an organ, a portion of an organ, a tumor, diseased tissue, or a whole patient outline. Alternatively, these structures of interest in specific organs such as the brain or prostate, for example, may be identified with various structure-specific automatic contouring and/or automatic segmentation software programs (subdividing an image into discrete regions) that outline or fill the shape of the structure of interest on each two-dimensional slice of a set of slices.

"As evolving technologies provide increasingly complicated radiation therapy treatment planning possibilities, the gap between actual clinical practice in treatment planning and possible best practices in treatment planning increases. Therefore improved methods for realizing and communicating improved results using emerging technological innovations are required."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventor's summary information for this patent: "This present invention provides a solution to the challenges inherent in achieving radiation therapy treatment planning best practices. In a method according to one embodiment, a series of steps provide for an improved radiation therapy dose distribution. A method for generating a radiation therapy dose distribution plan starts with selecting and downloading a treatment type from a database. Then an organ at risk (OAR) distance to target map is determined, wherein the OAR distance to target map comprises distances to a target organ for respective portions of at least one OAR, and wherein the OAR distances are determined from at least one segmented patient organ image. Now a cohort average dose distance to target histogram is selected and downloaded from the database. After which, a dose value to the portions of the at least one OAR are assigned to form a first 3D dose distribution map, wherein the dose values are from the selected cohort average dose distance to target histogram. Now a second 3D dose distribution map is determined based on a field arrangement determined by the treatment type, and the first 3D dose distribution map. The second 3D dose distribution map can now be optimized to generate a third 3D dose distribution map. Finally, a dose distance to target histogram is calculated for the patient using the third 3D dose distribution map and the distance to target map."

For additional information on this patent, see: Zankowski, Corey. Radiation Therapy Treatment Plan Improvement through Use of Knowledge Base. U.S. Patent Number 8774358, filed September 28, 2011, and published online on July 8, 2014. Patent URL:

Keywords for this news article include: Varian Medical Systems Inc.

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Source: Journal of Engineering

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