Off line quality control of a beam shaping device for radiation therapy

Patent metadata

Field	Value
Publication number	US-12442780-B2
Application number	US-202318454259-A
Country	US
Kind code	B2
Filing date	Aug 23, 2023
Priority date	Aug 24, 2022
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

A method for assessing a quality of a beam shaping device includes, establishing with a treatment planning system (TPS) the planned device design of the beam shaping device, manufacturing the beam shaping device according to the planned device design, establishing a CT-scan of the beam shaping device to yield an actual CT-image, determining dimensions and local materials densities from the actual CT-image, determining a calculated dose distribution in the treatment volume (V), and comparing the calculated dose distribution (cDD) with a reference dose distribution (rDD).

First claim

The invention claimed is:

1. A method for assessing a quality of a beam shaping device manufactured according to a planned device design for shaping one or more beams of accelerated particles emitted by a particle accelerator system, the method comprising,
(a) establishing with a treatment planning system (TPS) the planned device design of the beam shaping device suitable for shaping one or more beams of accelerated particles to mate a geometry of a treatment volume (V) of tissue comprising tumoral cells, for depositing specific doses (Dij) into specific locations within the treatment volume (V) thus defining a planned dose distribution (pDD) satisfying objectives on the dose deposition in the treatment volume set by a physician,
(b) manufacturing the beam shaping device according to the planned device design,
(c) establishing a CT-scan of the beam shaping device to yield an actual CT-image,
(d) determining dimensions and local materials densities from the actual CT-image,
(e) extending the actual CT-image to include the treatment volume (V),
(f) determining with a dose engine a calculated dose distribution in the treatment volume (V) obtained by virtually irradiating the treatment volume (V) with the one or more beams through a virtual beam shaping device having a geometry and a density defined by the device actual CT-image, and
(g) comparing the calculated dose distribution (cDD) with a reference dose distribution (rDD).

2. The method according to claim 1 , wherein the reference dose distribution (rDD) is,
a calculated planned dose distribution, (cpDD) obtained by,
first creating with the TPS a high-resolution planned device design corresponding to the planned device design but with a higher resolution, matching a resolution of the actual CT-image and,
second, determining the calculated planned dose distribution (cpDD) with the dose engine by virtually irradiating the treatment volume (V) with the one or more beams through the high-resolution planned device, or

the planned dose distribution (pDD) or a function thereof.

3. The method according to claim 2 , wherein the reference dose distribution (rDD) is either,
the calculated planned dose distribution (cpDD), and wherein the high-resolution planned device design is created with a voxel size which is equal to a CT-voxel size used for establishing the actual CT-image, with a tolerance of ±20%, or
the function of the planned dose distribution (pDD), which is the result of a transformation of the planned dose distribution (pDD), computed at a given spatial resolution and changing the voxel size to match the CT-voxel size with a tolerance of ±20%.

4. The method according to claim 1 , wherein the CT-scan of the beam shaping device is performed with a CT-voxel size of not more than 0.5 mm.

5. The method according to claim 4 , wherein the planned device design is created from the treatment plan (TP) using a TPS with a voxel size similar to or smaller than the CT-voxel size.

6. The method according to claim 1 , wherein comparing the calculated dose distribution (cDD) with the reference dose distribution (rDD) is performed with a gamma-evaluation and wherein in case a gamma value (γ) lower than or equal to a reference gamma-value (γr) is obtained in a predefined percentage of the voxels of the reference dose distribution (rDD), the beam shaping device is considered as in agreement with the planned device design, wherein γ is defined as a minimum of the following function,

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wherein, |d(cDD) −d(rDD)| is a distance between analyzed points, |D(cDD) −D(rDD) | are dose differences, and DTA and AD are scaling factors.

7. The method according to claim 6 , wherein in c

Assignees

• Ion Beam Applic
• Univ Pennsylvania

Inventors

• Hotoiu Lucian
• Labarbe Rudi
• Vander Stappen François
• Pakela Julia
• Teo Boonkeng Kevin
• Zou Wei

Classifications

• G01N23/06

  and measuring the absorption · CPC title

• G01N9/24

  by observing the transmission of wave or particle radiation through the material · CPC title

• A61N2005/1095

  Elements inserted into the radiation path within the system, e.g. filters or wedges · CPC title

• A61N5/1071

  for verifying the dose delivered by the treatment plan · CPC title

• A61N5/103 Primary

  Treatment planning systems · CPC title