EP-4738383-A2 - METHODS FOR OPTIMIZING TREATMENT TIME AND PLAN QUALITY FOR RADIOTHERAPY

EP4738383A2EP 4738383 A2EP4738383 A2EP 4738383A2EP-4738383-A2

Abstract

Described herein is a graphical user interface that receives a user-specified treatment time value and displays the resultant dose distributions to a target region and/or organs-at-risk (OARs). The dose distributions are depicted as dose volume histograms (DVHs). The user-specified treatment time value may be adjusted as desired and the DVHs for the target region and/or OARs may be correspondingly updated. In some variations, the graphical user interface may comprise bounded DVHs for the target region and/or OARs, where bounds of the DVH represent the range of dose variability between a short treatment time (e.g., T min ) and a long treatment time (e.g., T max ). In some variations, the graphical user interface includes a command button that triggers fluence map optimization using the user-specified treatment time.

Inventors

PRIVALIKHIN, Aleksei
VORONENKO, Yevgen
OLCOTT, Peter Demetri

Assignees

RefleXion Medical, Inc.

Dates

Publication Date: 20260506
Application Date: 20220222

Claims (15)

A graphical user interface for radiotherapy planning, the graphical user interface comprising: a bounded dose volume histogram (bDVH) for a target region comprising a lower bound DVH and an upper bound DVH that represent a range of radiation dose values to the-target region over a range of treatment delivery times; a treatment time selector configured to receive user input that specifies a treatment delivery time within the range of treatment times; and a variable dose volume histogram (DVH) for the target region that represents a radiation dose to the target region that corresponds to the specified treatment delivery time.
The graphical user interface of claim 1, wherein the lower bound DVH corresponds to a lower-limit treatment delivery time value and the upper bound DVH corresponds to an upper-limit treatment delivery time value, optionally wherein the lower-limit treatment delivery time value is a minimum treatment delivery time value, and the upper-limit treatment delivery time value is a maximum treatment delivery time value.
The graphical user interface of claim 1, wherein the bDVH for the target region further comprises shading between the upper bound DVH curve and the lower bound DVH curve.
The graphical user interface of claim 1, wherein the variable DVH curve for the target region changes between the upper bound DVH curve and the lower bound DVH curve according to the user input to the treatment time selector.
The graphical user interface of claim 1, wherein the treatment time selector is a graphical slider that is movable between a first limit that corresponds to a low-threshold treatment delivery time value and a second limit that corresponds to a high-threshold treatment delivery time value, and wherein moving the slider to a position between the first and second limits corresponds to selecting the treatment delivery time.
The graphical user interface of claim 1, wherein the treatment time selector is a graphical dial that is rotatable between a first limit corresponding to a low-threshold treatment delivery time and a second limit corresponding to a high-threshold treatment delivery time, and wherein setting the dial to a position between the first and second limits corresponds to selecting the treatment delivery time.
The graphical user interface of claim 1, further comprising a second bDVH for a volume of interest (VOI) comprising a second lower bound DVH curve and a second upper bound DVH curve that represent a range of radiation dose values to the VOI over the range of treatment delivery times, and a second variable DVH curve for the VOI that represents a radiation dose to the VOI that corresponds to the specified treatment delivery time, wherein optionally: a) the second bDVH for the VOI further comprises shading between the upper bound DVH curve and the lower bound DVH curve; or b) wherein the second variable DVH curve for the VOI changes between the upper bound DVH curve and the lower bound DVH curve of the second bDVH for the VOI according to the user input to the treatment time selector; or c) the VOI comprises a heart; or d) the VOI comprises a spinal cord; or e) the VOI comprises an esophagus; or f) the VOI comprises an organ-at-risk (OAR); or g) the graphical user interface further comprises a third bDVH for a second VOI comprising a third lower bound DVH curve and a third upper bound DVH curve that represent a range of radiation dose values to the second VOI over the range of treatment delivery times, and a third variable DVH curve for the second VOI that represents a radiation dose to the second VOI that corresponds to the specified treatment delivery time; or. h) the graphical user interface further comprises a third bDVH for a second VOI comprising a third lower bound DVH curve and a third upper bound DVH curve that represent a range of radiation dose values to the second VOI over the range of treatment delivery times, and a third variable DVH curve for the second VOI that represents a radiation dose to the second VOI that corresponds to the specified treatment delivery time, the graphical user interface further comprising a DVB-viewer selection menu that includes a graphical selection toggle for each of the first, second and third bDVHs, wherein a user-selection of a first toggle state displays the corresponding bDVH and a second toggle state hides the corresponding bDVH; or i) the graphical user interface further comprises a third bDVH for a second VOI comprising a third lower bound DVH curve and a third upper bound DVH curve that represent a range of radiation dose values to the second VOI over the range of treatment delivery times, and a third variable DVH curve for the second VOI that represents a radiation dose to the second VOI that corresponds to the specified treatment delivery time, wherein the first, second and third bDVHs are each depicted with different colors.
The graphical user interface of claim 1, further comprising a first text field that indicates a mean dose to the target region and a second text field that indicates a maximum dose to the target region for the specified treatment delivery time.
The graphical user interface of claim 1, further comprising a graphical indicator of the treatment delivery time specified by the treatment time selector.
The graphical user interface of claim 1, further comprising a command button that triggers treatment plan optimization with the treatment delivery time specified by the treatment time selector.
The graphical user interface of claim 1, wherein the lower-limit treatment delivery time value is a minimum treatment delivery time value, and the upper-limit treatment delivery time value is a maximum treatment delivery time value, wherein either: a) the minimum treatment delivery time value is determined by generating a fluence map comprising a set of beamlet values by iteratively adjusting the beamlet values based on a cost function comprising a treatment time penalty function such that the fluence map delivers a prescribed dose to the target region and changes of a cost function value between iterations of the beamlet values is less than a selected threshold, and calculating an amount of time to deliver the generated fluence map; or b) the maximum treatment delivery time value is determined by generating a fluence map comprising a set of beamlet values by iteratively adjusting the beamlet values based on a cost function comprising an organ-at-risk (OAR) dose penalty function such that the fluence map delivers a prescribed dose to the target region and changes of a mean dose to the OAR between iterations of the beamlet values is less than a selected threshold, and calculating an amount of time to deliver the generated fluence map.
A graphical user interface for radiotherapy planning, the graphical user interface comprising: a treatment time axis; a lower limit indicator on the treatment time axis, wherein the lower-limit indicator is at a minimum treatment time for delivering a prescribed dose to a target region; an upper limit indicator on the treatment time axis, wherein the upper-limit indicator is at a maximum treatment time for delivering the prescribed dose to the target region; and a treatment time indicator on the treatment time axis between the lower limit indicator and the upper limit indicator, wherein the treatment time indicator is at an initial treatment time for delivering the prescribed dose to the target region.
The graphical user interface of claim 12, wherein the initial treatment time is calculated by generating a fluence map comprising a set of radiation beamlet weights by iteratively adjusting the beamlet weights based on a cost function comprising an OAR penalty function such that the fluence map delivers the prescribed dose to the target region and changes of a cost function value between iterations of the beamlet weights is less than a selected threshold; and calculating an amount of time to deliver the generated fluence map.
The graphical user interface of claim 13, wherein the minimum treatment time is determined by generating a fluence map comprising a set of beamlet values by iteratively adjusting the beamlet values based on a cost function comprising a treatment time penalty function such that the fluence map delivers the prescribed dose to the target region and changes of a cost function value between iterations of the beamlet values is less than a selected threshold, and calculating an amount of time it takes to deliver the generated fluence map.
The graphical user interface of claim 13, wherein the maximum treatment time is determined by generating a fluence map comprising a set of beamlet values by iteratively adjusting the beamlet values based on a cost function comprising an organ-at-risk (OAR) dose penalty function such that the fluence map delivers a prescribed dose to the target region and changes of a mean dose to the OAR between iterations of the beamlet values is less than a selected threshold, and calculating an amount of time to deliver the generated fluence map.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63/153,256 filed February 24, 2021, the disclosure of which is hereby incorporated by reference in its entirety. BACKGROUND Treatment planning for radiotherapy involves defining a radiation fluence map that delivers the prescribed dose to tumors while limiting the irradiation of surrounding healthy tissue. A treatment plan fluence map contains a plurality of radiation beamlets that, when emitted by radiotherapy system, will deliver the prescribed dose to tumors. Due to the limitations of external beam radiotherapy systems and the variable shapes, sizes, and locations of tumors, delivering a prescribed dose to a tumor invariably exposes surrounding tissue to some level of radiation. Various system and/or dose limitations as well as treatment objectives may be represented as constraints and objectives, some of which may be translated into a cost function. A cost function, which comprises a plurality of penalty functions, is defined during treatment planning to guide the optimization and generation of the fluence map so that the irradiation of non-tumor tissue is kept below a selected threshold. For example, cost functions may comprise one or more penalty functions that "discourage" excessive radiation dose to organs-at-risk (OARs), and/or one or more penalty functions that "discourage" abrupt fluence changes and/or the emission of an excessive amount of radiation by the therapeutic radiation source (e.g., total radiation emitted by a therapeutic radiation source, in monitor units). The penalty functions of a cost function may be weighted relative to each other, where their relative weights may correspond with their relative priorities. For example, a penalty function that limits dose to the spinal cord may have a higher weight than a penalty function that reduces the number of multi-leaf collimator (MLC) leaf transitions. In many cases, the penalty function weights are defined by the user (e.g., clinician), and may be adjusted during treatment planning. However, depending on the complexity of the cost function and the patient's disease state, it may be difficult to understand the effect of a particular combination of penalty function weights on the generated fluence map and/or the resultant dose distribution to the tumor and/or OARs (collectively, the volumes of interest or VOIs). More generally, it can be challenging to understand the effect of treatment planning constraints and/or objections on the dose distribution. Accordingly, improved methods to aid a user during treatment planning are desired. SUMMARY Described herein is a graphical user interface that comprises a treatment time selector that is configured to receive user input that specifies a treatment time, a dose distribution plot for a VOI (e.g., a target region, an OAR, any contoured volume) that depicts a range of dose distributions for a range of treatment times, and a variable dose distribution plot that represents the dose distribution for the VOI at the specified treatment time. In one variation, the graphical user interface may comprise a bounded volume histogram (bDVH) for a VOI, where the lower and the upper bounds of the bDVH represent the range of dose distributions over a range of treatment times between Tmin and Tmax, a treatment time selector configured to receive user input that specifies a treatment time within the range of treatment times, and a variable DVH that represents the dose distribution to the VOI for the specified treatment time. The variable dose distribution plot (e.g., DVH) may be updated as the user adjusts the treatment time. In some variations, the variable dose distribution plot may be dynamically updated in response to user-selection of different treatment times. For example, the variable dose distribution plot may be updated without reoptimizing the fluence map. The VOI may be a target region such as a tumor or a radiation-avoidance region such as an OAR. Some variations of the graphical user interface may comprise bDVH plots and variable DVH plots for multiple VOIs, including any combination or number of target regions and/or radiation-avoidance regions. Also described herein are methods for generating a graphical user interface that comprises a dose distribution plot for a VOI (e.g., a target region, an OAR) that depicts a range of dose distributions for a range of treatment times and dynamically updates dose distribution plots (e.g., DVH) for one or more VOI when a user selects a different treatment time within the range of treatment times (i.e., Tmin ≤ tselected ≤ Tmax). One variation of a method for generating a graphical user interface that depicts a range of dose distributions for a range of treatment times comprises calculating a minimum treatment time Tmin to deliver a prescribed dose to one or more VOIs, calculating a maximum treatment time Tmax to deliver a prescribed dose to one or more