EP-4735109-A1 - SYSTEM FOR ADAPTIVE RADIOTHERAPY TREATMENT DELIVERY

EP4735109A1EP 4735109 A1EP4735109 A1EP 4735109A1EP-4735109-A1

Abstract

Disclosed herein is a radiotherapy system comprising: a radiation delivery system for delivering radiation to a target region of a patient; a computer data store configured to store a current radiotherapy treatment plan, the current radiotherapy treatment plan comprising a plurality of control points, each control point defining a value of at least one radiation delivery variable; a delivery control module configured to retrieve the current radiotherapy treatment plan and control the radiation delivery system to deliver radiation to the target region based on the current radiotherapy treatment plan; and a plan adaptation module.

Inventors

WOODHEAD, PETER

Assignees

Elekta Limited

Dates

Publication Date: 20260506
Application Date: 20240627

Claims (20)

1. A radiotherapy system comprising: a radiation delivery system for delivering radiation to a target region of a patient; a computer data store configured to store a current radiotherapy treatment plan, the current radiotherapy treatment plan comprising a plurality of control points, each control point defining a value of at least one radiation delivery variable; a delivery control module configured to retrieve the current radiotherapy treatment plan and control the radiation delivery system to deliver radiation to the target region based on the current radiotherapy treatment plan; and a plan adaptation module configured to, during delivery of radiation according to the current radiotherapy plan: receive information about the target region; adapt the current radiotherapy treatment plan based on the information to generate a new current radiotherapy treatment plan, wherein the adapting comprises modifying at least one radiation delivery variable of at least one control point of the current radiotherapy treatment plan; and store the new current radiotherapy treatment plan in the computer data store.
2. The system of any preceding claim, wherein the current radiotherapy treatment plan comprises a treatment goal based on a prescribed dose and adapting the current radiotherapy treatment plan comprises modifying the at least one radiation delivery variable based on the treatment goal.
3. The system of any preceding claim, wherein adapting the current radiotherapy treatment plan further comprises adding a control point to the current radiotherapy treatment plan and/or removing a control point from the current radiotherapy treatment plan.
4. The system of any preceding claim, wherein the at least one radiation delivery variable represents one of: a gantry angle, at what beam energy the radiation beam should be applied, the duration of application of a radiation beam at gantry angle, a weight of a particular beam, or a patient position parameter.
5. The system of any preceding claim, wherein the delivery control module is further configured to retrieve the new current radiotherapy treatment plan and to control the radiation delivery system to deliver radiation to the target region based on the new current radiotherapy treatment plan.
6. The system of any preceding claim, wherein the delivery control module is further configured to, during delivery of radiation according to the current radiotherapy treatment plan, retrieve the new current radiotherapy treatment plan and to control the radiation delivery system to change to delivering radiation to the target region based on the new current radiotherapy treatment plan.
7. The system of any preceding claim, wherein the plan adaptation module is further configured to, during delivery of radiation according to the new current radiotherapy treatment plan, adapt the new current radiotherapy treatment plan based on further information about the target region to generate a further new radiotherapy treatment plan, and store the further new current radiotherapy treatment plan in the computer data store.
8. The system of any preceding claim, wherein adapting the current radiotherapy treatment plan further comprises modifying at least one radiation delivery variable of a range of the plurality of control points, and optionally further comprises removing at least one control point subsequent to the range.
9. The system of claim 8, wherein the range of the plurality of control points corresponds to the control points that are yet to be delivered in a present fraction of radiotherapy.
10. The system of any preceding claim, wherein the adapting is further based on the remaining dose to be delivered in a present fraction of radiotherapy.
11. The system of any preceding claim, the system further comprising an imaging system for obtaining images of the target region of the patient, and wherein the information about the target region is based on imaging information acquired by the imaging system.
12. The system of any preceding claim, wherein the information about the target region comprises positional information measured during the delivery of radiation, the positional information relating to at least one of: a patient position, and a radiation delivery system position.
13. The system of any preceding claim, wherein the plan adaptation module is further configured to determine a drift of the target region based on the information and to adapt the current radiotherapy treatment plan in response to the drift.
14. The system of any preceding claim, wherein delivery of radiation according to the current radiotherapy plan is delivery of a current control point associated with the current radiotherapy treatment plan; and wherein the at least one control point of the current radiotherapy treatment plan is a future control point scheduled at a future time point compared to the current control point.
15. The system of any preceding claim, wherein the plan adaptation module is configured to store the new current radiotherapy treatment plan in the computer data store by sending the new current radiotherapy treatment plan to the delivery control module.
16. The system of any preceding claim, wherein the new current radiotherapy treatment plan is a plan update, and wherein the delivery control module is configured to modify the current radiotherapy treatment plan during delivery based on the plan update.
17. The system of any preceding claim, wherein the delivery control module is configured to determine timing and/or speed information for delivering the new current radiotherapy treatment plan using the radiation delivery system.
18. The system of any preceding claim, wherein a monitor unit, MU, count determined by the system is continuous across the current radiotherapy treatment plan and the new current radiotherapy treatment plan.
19. The system of any preceding claim, wherein the new current radiotherapy treatment plan comprises an indication of an authorised monitor unit, MU, count that the delivery control module is authorised to deliver.
20. A method of generating therapeutic radiation, the method comprising: at a computer data store, storing a current radiotherapy treatment plan, the current radiotherapy treatment plan comprising a plurality of control points, each control point defining a value of at least one radiation delivery variable; by a delivery control module, retrieving the current radiotherapy treatment plan and controlling the radiation delivery system to deliver radiation to a target region of a patient based on the current radiotherapy treatment plan; and by a plan adaptation module, during delivery of radiation according to the current radiotherapy plan: receiving information about the target region; adapting the current radiotherapy treatment plan based on the information to generate a new current treatment plan, wherein the adapting comprises modifying at least one radiation delivery variable of at least one control point of the current radiotherapy treatment plan; and storing the new current radiotherapy treatment plan in the computer data store.

Description

System for adaptive radiotherapy treatment delivery This disclosure relates to radiotherapy, and in particular to a system and method for delivering adaptive radiotherapy to a patient. Background Radiotherapy can be described as the use of ionising radiation, such as X-rays, to treat a human or animal body. Radiotherapy is commonly used to treat tumours within the body of a patient or subject. In such treatments, ionising radiation is used to irradiate, and thus destroy or damage, cells which form part of the tumour. In radiotherapy treatment, it is desirable to deliver a prescribed dose of radiation to a target region, e.g. a tumour, of a patient and to limit irradiation of other parts of the patient, e.g. healthy tissue and organs at risk (OARs). The treatment planning procedure typically involves obtaining one or more medical images, such as a CT image of the patient, and segmenting them to identify the target region and OARs near the target region. The segmentation process can be performed manually or using auto-segmentation techniques. The clinician determines radiation treatment parameters, for example by prescribing a radiation dose to be delivered to the target region and maximum doses which can safely be delivered to the various OARs. The treatment planning procedure may then involve optimizing various radiation delivery variables to meet the prescribed radiation treatment parameters, for example determining the number of sessions (or 'fractions') over which radiotherapy should be conducted, the angles at which the radiation beam should be applied during each fraction, at what beam energy, the duration of application of the radiation beams at these angles, and the beam shape(s) at each angle of delivery. The clinician can be assisted by software during some or all of these steps. This aspect of treatment planning, conducted in advance of the patient's treatment (and sometimes between treatment fractions if there are gradual changes), can be described as 'offline' treatment planning. However, the characteristics of the tumour, such as its shape and size, may change over the course of the multiple fractions of treatment. Similarly, other patient information and characteristics of the patient's anatomy can change between fractions, in both cases in a less foreseeable way. Accordingly, 'online' adaptive radiotherapy techniques may be used to update and re-optimise the radiotherapy treatment plan and/or delivery variables immediately prior to the patient's treatment. According to online adaptive radiotherapy techniques, the patient is imaged again immediately prior to treatment, and the treatment plan for that day's fraction may be adjusted and/or reoptimized according to the latest available medical images. Online adaptive radiation therapy techniques, as part of an online treatment workflow, therefore allow inter-fraction anatomical changes to be taken into account. Additionally, the location or orientation of the tumour may change during a fraction session, which may be due to intra-fraction motion, such as patient breathing. In such cases, intra-fractional imaging during delivery can provide information that enables the implementation of 'real-time' adaptation in the form of either 'gating' of the radiation delivery, i.e. turning the beam on and off periodically, and/or providing an over-ride to the multi-leaf collimator control ('tracking') in order to shape the beam differently to the shape specified in the treatment plan. However, current 'real-time' adaptation techniques involve adapting a fixed treatment plan. Such mechanisms require 'over-ride' features in the radiation delivery system in order to intercept and modify the execution of this original, fixed treatment plan. Such existing 'real-time' adaptation is effective, but only makes use of only some of the degrees of freedom available within the radiotherapy delivery system for control and optimisation of radiotherapy delivery. It is desirable to further optimise adaptive treatment, and to utilise further degrees of freedom of the delivery system for realtime adaptation in order to further improve the delivery of radiation to the tumour and reduce the delivery of radiation to adjacent healthy tissue. The present invention seeks to address these and other disadvantages encountered in the prior art by providing an improved system and method for delivering radiotherapy to a patient. Summary An invention is set out in the independent claims. Optional features are set out in the dependent claims. Figures Specific examples are now described, by way of example only, with reference to the drawings, in which: Fig. 1 shows a radiotherapy device or apparatus according to the present disclosure; Fig. 2 shows a radiotherapy treatment workflow for fixed treatment plan delivery; Fig. 3 shows a radiotherapy treatment workflow for fixed treatment plan delivery with gating and/or tracking; Fig. 4 shows a radiotherapy system according to the present disclos