US-12616854-B2 - Monitoring and control of neutron beam systems

US12616854B2US 12616854 B2US12616854 B2US 12616854B2US-12616854-B2

Abstract

A method for monitoring and controlling neutron beams includes performing a calibration process for a monitoring dosimeter at a first set of conditions for directing a neutron beam towards an object location, the neutron beam being emitted from a neutron-generating target in response to an incident charged particle beam, the process comprising: obtaining data indicating a first neutron flux measured by the monitoring dosimeter between the monitoring dosimeter and the object location, the monitoring dosimeter offset from the axis by a distance equal to or greater than the beam radius; obtaining data indicating a second neutron flux measured by a reference dosimeter between the target and the object location; storing calibration data including a correlation between the first neutron flux and the second neutron flux; and based on the calibration data, using the monitoring dosimeter to monitor neutron flux incident on a patient during boron neutron capture therapy treatment.

Inventors

Jedediah Styron
Jonathan David McCoy
Charles Leon Lee
Matthew Alan Core

Assignees

TAE LIFE SCIENCES, LLC

Dates

Publication Date: 20260505
Application Date: 20230829

Claims (16)

1 . A method, comprising: obtaining a measured neutron flux output by a dosimeter configured to monitor a neutron flux of a neutron beam during a boron neutron capture therapy (BNCT) treatment on a patient, wherein neutrons in the neutron beam are emitted from a neutron-generating target in response to a charged particle beam incident on the neutron-generating target; determining an expected neutron flux based on an energy of the charged particle beam; and in response to determining that a difference between the measured neutron flux and the expected neutron flux exceeds a first threshold difference, performing one or more actions, wherein performing the one or more actions comprises adjusting a duration of the boron neutron capture therapy (BNCT) treatment based on the difference between the measured neutron flux and the expected neutron flux.
2 . The method of claim 1 , comprising: determining, based on the measured neutron flux, that a neutron dose delivered to the patient matches or exceeds an intended neutron dose to be delivered to the patient; and in response to determining that the neutron dose delivered to the patient matches or exceeds the intended neutron dose, transmitting an instruction to a neutron beam system outputting the neutron beam to cease outputting the neutron beam.
3 . The method of claim 1 , comprising: determining the expected neutron flux based on a current of the charged particle beam.
4 . The method of claim 1 , further comprising: obtaining sensor data from a sensor configured to monitor a parameter of a neutron beam system outputting the neutron beam; determining, using the sensor data, a cause of the difference between the measured neutron flux and the expected neutron flux; and performing the one or more actions based on the cause of the difference between the measured neutron flux and the expected neutron flux.
5 . The method of claim 4 , wherein the parameter is selected from the group consisting of: a current of the charged particle beam; an energy of the charged particle beam; a temperature of the neutron-generating target; a photon flux emitted from the neutron-generating target; and a symmetry of the neutron beam.
6 . The method of claim 4 , wherein the cause of the difference between the measured neutron flux and the expected neutron flux comprises one of the group consisting of: an energy of an accelerator configured to accelerate the charged particle beam towards the neutron-generating target; a directionality of the charged particle beam; a focus of the charged particle beam; a raster pattern of the charged particle beam; a thickness of the neutron-generating target; a type of a collimator located between the neutron-generating target and the patient; a position of the collimator located between the neutron-generating target and the patient; and a position of the patient.
7 . The method of claim 4 , wherein the one or more actions is selected from the group consisting of: adjusting an energy of an accelerator configured to accelerate the charged particle beam towards the neutron-generating target; adjusting a directionality of the charged particle beam; adjusting a focus of the charged particle beam; adjusting a raster pattern of the charged particle beam; adjusting a type of a collimator located between the neutron-generating target and the patient; adjusting a position of the collimator located between the neutron-generating target and the patient; and adjusting a position of a structure supporting the patient.
8 . The method of claim 4 , wherein: the parameter of the neutron beam system comprises a current of the charged particle beam or an energy of the charged particle beam; the cause of the difference between the measured neutron flux and the expected neutron flux comprises a setting of an accelerator configured to accelerate the charged particle beam; and the one or more actions comprise adjusting the setting of the accelerator.
9 . The method of claim 4 , wherein: the parameter of the neutron beam system comprises a temperature of the neutron-generating target; the cause of the difference between the measured neutron flux and the expected neutron flux comprises a directionality of the charged particle beam; and the one or more actions comprise adjusting the directionality of the charged particle beam.
10 . The method of claim 4 , wherein: the parameter of the neutron beam system comprises a temperature of the neutron-generating target; the cause of the difference between the measured neutron flux and the expected neutron flux comprises a focus of the charged particle beam; and the one or more actions comprise adjusting the focus of the charged particle beam.
11 . The method of claim 4 , wherein: the parameter of the neutron beam system comprises a temperature of the neutron-generating target; the cause of the difference between the measured neutron flux and the expected neutron flux comprises a raster pattern of the charged particle beam; and the one or more actions comprise of adjusting the raster pattern of the charged particle beam.
12 . The method of claim 4 , wherein: the parameter of the neutron beam system comprises a temperature of the neutron-generating target; the cause of the difference between the measured neutron flux and the expected neutron flux comprises a thickness of the neutron-generating target; and the one or more actions comprise at least one of adjusting a directionality of the charged particle beam, adjusting a focus of the charged particle beam, or adjusting a raster pattern of the charged particle beam.
13 . The method of claim 4 , wherein: the parameter of the neutron beam system comprises a photon flux emitted from the neutron-generating target; the cause of the difference between the measured neutron flux and the expected neutron flux comprises a setting of an accelerator configured to accelerate the charged particle beam; and the one or more actions comprise adjusting the setting of the accelerator.
14 . The method of claim 4 , wherein: the parameter of the neutron beam system comprises a symmetry of the neutron beam; the cause of the difference between the measured neutron flux and the expected neutron flux comprises a position of the patient; and the one or more actions comprise adjusting a position of a structure supporting the patient.
15 . The method of claim 4 , wherein: the parameter of the neutron beam system comprises a symmetry of the neutron beam; the cause of the difference between the measured neutron flux and the expected neutron flux comprises a type of a collimator located between the neutron-generating target and the patient; and the one or more actions comprise adjusting the type of the collimator located between the neutron-generating target and the patient.
16 . The method of claim 4 , wherein: the parameter of the neutron beam system comprises a symmetry of the neutron beam; the cause of the difference between the measured neutron flux and the expected neutron flux comprises a position of a collimator located between the neutron-generating target and the patient; and the one or more actions comprise adjusting the position of the collimator located between the neutron-generating target and the patient.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of the U.S. Provisional Patent Application No. 63/402,286 filed Aug. 30, 2022, and of the U.S. Provisional Patent Application No. 63/504,981 filed May 30, 2023, which are incorporated herein by reference in their entirety. FIELD The subject matter described herein relates generally to systems, devices, and methods for monitoring neutron radiation and/or controlling neutron beams. BACKGROUND Boron neutron capture therapy (BNCT) is a modality of treatment of a variety of types of cancer, including some of the most difficult types. BNCT is a technique that selectively aims to treat tumor cells while sparing the normal cells using a boron compound. The boron compound allows for efficient uptake by a variety of cell types and selective drug accumulation at target sites, such as tumor cells. Boron loaded cells can be irradiated with neutrons (e.g., in the form of a neutron beam). The neutrons react with the boron to eradicate the tumor cells. Neutron beams for BNCT can be generated through various techniques. In some cases, this is accomplished by colliding protons with a neutron generating target containing lithium-7 to generate neutrons according to the Li-7(p,n)Be-7 nuclear reaction. In other cases, the neutrons can be generated by impacting a target containing beryllium-9 with a proton beam (Be-9(p,n)B-9) or deuteron beam (Be-9(d,n)B-10) at different energies. Still other techniques can be used. The charged particles react with nuclei in the target to emit a beam of raw neutrons that can be used for BNCT. Generally, a BNCT treatment plan dose is correlated to the charged particle current, or number of charged particles incident on the neutron generating target, which is not a direct measure of the number of neutrons produced. For example, if the charged particle beam (in this case protons) veers off the target region onto the substrate the measured current will be constant even though no neutrons are being produced. In addition, the charged particle current is unable to monitor target conditions, e.g., changes to the lithium target via nuclear depletion, mechanical failure, or chemical reactions. Therefore, measuring the charged particle current as a surrogate to neutrons is valid if the charged particle beam does not deviate from the target and the target material remains a uniform thickness, composition, and density throughout the treatment. For these and other reasons, needs exist for improved systems, devices, and methods for monitoring neutron radiation and/or controlling neutron beams. SUMMARY The subject matter described herein relates generally to systems, devices, and methods for monitoring and controlling neutron beams. Embodiments of a neutron beam monitoring and control system are described in an example context of a BNCT system configured to output a neutron beam in an epithermal energy range. The embodiments described herein are usable in non-BNCT applications as well. The present subject matter can be used to provide a neutron measurement that provides a real-time monitor of the treatment conditions. In addition, this subject matter permits active correction, and can reduce the impact of time-consuming calibrations for each treatment plan on the BNCT treatment facility throughput. The present subject matter can permit for a direct relationship to be established between the desired treatment plan dose and a neutron measurement. Also provided are methods to monitor real-time fluctuations in the neutron rate and methods to control the precise delivery of a specific quantity and distribution of dose at the desired location. BRIEF DESCRIPTION OF DRAWINGS The details of the subject matter set forth herein, both as to its structure and operation, may be apparent by study of the accompanying figures, in which like reference numerals refer to like parts. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the subject matter. Moreover, all illustrations are intended to convey concepts, where relative sizes, shapes and other detailed attributes may be illustrated schematically rather than literally or precisely. FIG. 1A shows a schematic view depicting an example of a neutron beam system in accordance with the present disclosure. FIG. 1B shows a schematic view depicting an example of a neutron beam system for use in BNCT in accordance with the present disclosure. FIG. 2A shows a perspective view depicting an example of a neutron generating target in accordance with the present disclosure. FIG. 2B shows a side view depicting an example of an assembly for housing a neutron generating target in accordance with the present disclosure. FIG. 2C shows a cross-sectional view depicting an example of an assembly for housing a neutron generating target in accordance with the present disclosure. FIG. 3A shows a cross-sectional view depicting an example embodiment of a n