Radiation source and beam localization using microstructured conductive elements with spatiotemporal design

Abstract

Described here are systems and methods for determining the spatial location of a radiation source, such as a radiation source moving in a brachytherapy applicator (e.g., an afterloader catheter, a needle) during a brachytherapy procedure. Conductive elements coupled to the brachytherapy applicator are operable as radiation detectors that can measure spatiotemporal signal data to localize the position of the radiation source as it moves within the brachytherapy applicator. The conductive elements may include micro-structured wires (e.g., coaxial micro-structured wires), micro-structured conductive strips, conductive thin films, or other patterns of conductors. Other detector types may include ion chambers, solid-state detectors, or resistive electrodes.

Description

RADIATION SOURCE AND BEAM LOCALIZATION USING MICROSTRUCTURED CONDUCTIVE ELEMENTS WITH SPATIOTEMPORAL DESIGNCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 521,519, filed on June 16, 2023, and entitled “RADIATION SOURCE AND BEAM LOCALIZATION USING MICROSTRUCTURED CONDUCTIVE ELEMENTS WITH SPATIOTEMPORAL DESIGN,” which is herein incorporated by reference in its entirety.BACKGROUND

[0002] Brachytherapy is a type of cancer treatment that uses high-dose radiation sources to kill cancer cells. This treatment involves placing small, temporary or permanent radiation sources, which may be referred to as radioactive seeds, directly into or near the tumor. The radioactive seeds deliver a high dose of radiation to the cancer cells while minimizing exposure to surrounding healthy tissue. Brachytherapy applicators, such as needles or afterloader catheters, are used to deliver the radioactive seeds to locations in the tissue as determined by a radiation treatment plan. Multiple brachytherapy applicators (e.g., 10-20) may often be used to deliver the radioactive seeds into the tissue to locally treat the tumor.SUMMARY OF THE DISCLOSURE

[0003] In some aspects, the present disclosure provides a radiation source localization system that includes a brachytherapy applicator extending along a length from a proximal end to a distal end and having an internal lumen extending therethrough. At least one conductive element is coupled to the brachytherapy applicator to measure radiation emitted by a radiation source moving through the internal lumen of the brachytherapy applicator.

[0004] In some other aspects, the present disclosure provides a method for daily quality assurance (QA) of a brachytherapy system. The method includes arranging a brachytherapy source within a brachytherapy applicator at a predetermined treatment position along the brachytherapy applicator; acquiring spatiotemporal signal data using a conductive element coupled to the brachytherapy applicator while the brachytherapy source is emitting radiation at the predetermined treatment length; determining a location of the brachytherapy source fromthe spatiotemporal signal data; and generating daily QA data by comparing the determined location to the predetermined treatment length.

[0005] In still other aspects, the present disclosure provides a method for localizing a radiation source during treatment. The method includes arranging a brachytherapy source within a brachytherapy applicator; acquiring spatiotemporal signal data using a conductive element coupled to the brachytherapy applicator while the brachytherapy source is moved within the brachytherapy applicator to a treatment position; determining a location of the brachytherapy source from the spatiotemporal signal data; and generating a report indicating the location of the brachytherapy source within the brachytherapy applicator.

[0006] In yet other aspects, the present disclosure provides a method for localizing a plurality of brachytherapy applicators. The method includes arranging at least one brachytherapy source within a plurality of brachytherapy applicators positioned within a treatment region of a patient; acquiring spatiotemporal signal data for each of the plurality of brachytherapy applicators using a conductive element coupled to each of the plurality of brachytherapy applicators while the at least one brachytherapy source is moved within the at least one of the plurality of brachytherapy applicators; determining a location of each of the plurality of brachytherapy applicators from the spatiotemporal signal data; and generating a report indicating the location of each of the plurality of brachytherapy applicators.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1A shows an example radiation source localization assembly in accordance with some aspects of the present disclosure.

[0008] FIG. IB shows an example radiation source localization assembly in accordance with some other aspects of the present disclosure, in which the radiation source localization assembly is at least partially constructed as a well-type ionization chamber.

[0009] FIG. 2 shows example single and dual wire configurations for conductive elements within the radiation source localization assembly.

[0010] FIG. 3 shows an example of source locations check with a single wire measuring sequentially in four locations along a brachytherapy needle.

[0011] FIG. 4 is a flowchart setting forth the steps of an example method for performing daily quality assurance (“QA”) using a radiation source localization system as described in the present disclosure.

[0012] FIG. 5 shows an example of daily QA with dual wires at the selected treatment length of 1200mm. Black line is the calibration curve, overlayed with the real time signals from the two wires (sl,s2) processed as (s2-sl) / (sl+s2). The intersection of the two provides an immediate visual of the PASS / FAIL result of the daily QA

[0013] FIG. 6 is a flowchart setting forth the steps of an example method for localization a radiation source location in real-time using a radiation source localization system as described in the present disclosure.

[0014] FIG. 7 is a flowchart setting forth the steps of an example method for localizing a plurality of brachytherapy applicators arranged within a treatment region using a radiation source localization system as described in the present disclosure.

[0015] FIG. 8 is a block diagram of an example radiation source localization system that can implement the methods described in the present disclosure.

[0016] FIG. 9 is a block diagram of example components that can implement the system of FIG. 8.DETAILED DESCRIPTION

[0017] Described here are systems and methods for determining the spatial location of a radiation source, such as a radioactive seed moving in a brachytherapy applicator (e.g., an afterloader catheter, a needle) during an HDR brachytherapy procedure and / or an electronic brachytherapy source (e.g., a radiation emitter, such as an x-ray emitter, that is moving within a brachytherapy applicator). Additionally or alternatively, the systems and methods may provide for the localization and / or characterization of moving or deforming ionizing radiation beams, such as external radiotherapy beams or other beams or sources. In still other examples, the radiation sources that can be measured using the systems and methods described in the present disclosure may include radiation contamination, such as radiation contamination on an object or in a region or area.|0018] In general, the disclosed systems and methods make use of a radiation source localization assembly that includes one or more conductive elements arranged on, arranged within, or otherwise coupled to a brachytherapy applicator to detect the spatial location of a radiation source moving within the brachytherapy applicator. A conductive element may include a wire loop (e.g., micro-structured wires), a thin film conductor, a strip conductor, or other conductor that is patterned to allow for the conversion of a temporal signal measured on the conductive element into spatial information. In some examples, more than one conductiveelement may be used, such as a series of conductive elements arranged along the length of the brachytherapy applicator.

[0019] As one non-limiting example, the radiation source localization assembly may include one or more conductive elements constructed of micro-structured wire(s) with a spatiotemporal patterning or other design that is suitable for characterization of spatiotemporal properties of radiation generated by moving and / or changing radiation sources and / or beams. The conductive elements may be composed of a suitable conductive material, including a metal, a metal alloy, a conductive polymer, or the like.

[0020] The radiation source localization systems and methods described in the present disclosure provide information about the activity and the location of a radiation source (e.g., physical radioactive seed, electronic brachytherapy source) in a brachytherapy applicator (e.g., a needle and / or afterloader catheter) in real-time and in vivo (i.e., during treatment with brachytherapy applicators in the patient). Conventionally Gafchromic films, radiochromic films, or a monitoring camera are used to visualize a radioactive seed location in a needle in open air. During HDR brachytherapy treatment the seed location is not monitored within the patient using these conventional techniques, but is instead inferred by the afterloader device considering the length of the wire pushing the seed into the catheter. In low dose-rate brachytherapy, conventional techniques for monitoring seed location within the needles is to monitor the seed location prior to insertion by exposing a film with a preloaded needle. The dose distribution may be computed by localizing the seeds on a CT scan of the patient, which may be acquired several days after the implant is completed.

[0021] The radiation source localization devices described in the present disclosure are low cost, allowing for them disposable if used with interstitial needles during an implant. The radiation source localization devices may also be self-powered. No electric potential needs to be applied to the devices. Passive reading of signals can be made when radiation is present in the devices. Therefore, the radiation source localization devices described in the present disclosure are safe to use either on the patient skin surface or interstitially within the patient tissues.

[0022] Referring to FIG. 1A, an example radiation source localization assembly 10 is illustrated. In this example, the radiation source localization assembly 10 is coupled to a brachytherapy applicator 12, which may be a brachytherapy needle, a brachytherapy catheter, a brachytherapy applicator, or the like. In other implementations, the radiation source localization assembly 10 may be coupled to other devices or structures to monitor the locationof a moving and / or changing radiation source and / or beam. For example, the radiation source localization assembly 10 may be coupled to a borehole or downhole inspection system, or the like, for non-destructive testing of a pipe or other such enclosed volume. These implementations may be used, for example, to monitor damage to pipelines (e.g., oil and gas pipelines), detect leaks in pipelines, detect radiation contamination in a pipe or other enclosed volume, and so on.

[0023] The brachytherapy applicator 12 generally includes a tubular structure (e.g., a catheter, a needle) that extends from a proximal end 14 to a distal end 16. In these instances, the brachytherapy applicator 12 has an internal lumen 18 extending from the proximal end 14 to the distal end 16. A radiation source 20 (e.g., a radioactive seed, an electronic brachytherapy source) may be arranged within the internal lumen 18 of the brachytherapy applicator 12. As the radiation source 20 is moved relative to the radiation source localization assembly 10, temporal changes in radiation emitted by the radiation source 20 are measured and converted to spatial information for localizing the radiation source 20, as described below in more detail.

[0024] The radiation source localization assembly 10 also includes one or more conductive elements 30 that are coupled to a surface of the brachytherapy applicator 12. Primary radiation impinging upon the conductive element(s) 30 generates charge carrier, ionization, or high energy currents. The latter do not require external electric fields to move because their large energy is from the primary radiation. Therefore the radiation source localization assembly 10 may be self-powered and, thus, no voltage needs to be applied to it. Also, charge carriers in the presence of contact potentials between conducting electrodes can lead to self-powered cun-ent.

[0025] The conductive element(s) 30 may be coupled to the external surface of the brachytherapy applicator 12, an internal surface of the brachytherapy applicator 12, or both. Thus, in some examples the radiation source localization assembly 10 may include one or more conductive elements 30 coupled to the external surface of the brachytherapy applicator 12, one or more conductive elements 30 coupled to the internal surface of the brachytherapy applicator 12, or combinations thereof. Multiple conductive elements 30 may be used to provide multiple signals measured in different regions of the space irradiated by the radiation source. This information may be used for reconstruction of a 3D location of the radiation source, the brachytherapy applicator(s) 12, or both.

[0026] Each conductive element 30 may partially surround the brachytherapy applicator 12 (e.g., partially surround a circumference of the brachytherapy applicator 12), ormay completely surround the brachytherapy applicator (e.g., completely circumscribe the circumference of the brachytherapy applicator 12). Additionally or alternatively, the conductive elements 30 may include a combination of one or more conductive elements 30 that partially surround the brachytherapy applicator 12 and one or more conductive elements 30 that completely surround the brachytherapy applicator 12. More generally, each conductive element 30 is an extended detector over or along a surface of the brachytherapy applicator 12 and is patterned in such a way that it allows conversion of temporal signals to spatial information about the radiation source location.

[0027] As mentioned above, a conductive element 30 may include a wire loop, a thin film conductor, a strip conductor, or other pattern of conductor or conductive material on a substrate, which may be a flexible substrate. As one example, a conductive element 30 may include micro-structured wire that is looped around the circumference or other periphery of the brachytherapy applicator 12. The conductive element(s) 18 can include a single wire that is looped around one portion of the brachytherapy applicator 12, or a single wire that is looped around two or more portions of the brachytherapy applicator 12. In these instances, spatial encoding is provided by a single wire that is looped around the brachytherapy applicator 12 at one or more locations along the length of the brachytherapy applicator 12. Additionally or alternatively, the conductive element(s) 18 may include two or more wires that are each looped around different portions of the brachytherapy applicator 12 along the length of the brachytherapy applicator 12. In these instances, spatial encoding is provided by the two or more wires as they are looped around the brachytherapy applicator 12. An example of a single- wire and a dual-wire spatial encoding configuration is illustrated in FIG. 2.

[0028] As another example, a conductive element 30 may include a micro-structured strip of conductive material that is coupled to the brachytherapy applicator 12. As yet another example, the conductive element 30 may include a thin film conductor that is coupled to the brachytherapy applicator 12. The thin film may be patterned to provide for characterization of spatiotemporal properties of radiation generated by moving and / or changing radiation sources and / or beams.

[0029] In still other examples, the conductive element 30 may include other patterning of conductive material on and / or within the brachytherapy applicator 12. For instance, the conductive element 30 may include conductive material that is deposited on a surface of the brachytherapy applicator 12. In other instances, the conductive element 30 may include a conductive substrate that is etched or otherwise has portions of conductive material removedto provide a patterning for characterizing spatiotemporal properties of radiation generated by moving and / or changing radiation sources and / or beams. As a non-limiting example, the conductive element 30 may include removing portions of conductive material (e.g., via etching or the like) on a surface of a metal brachytherapy needle.

[0030] In another example, a resistive electrode may be employed with signal acquired at both the proximal end 14 and the distal end 16 of the brachytherapy applicator 12. In these instances, the radiation source location may be inferred by the time difference between the two signals.

[0031] The conductive element(s) 30 may operate to detect radiation using one or more detection modalities, such as ion chambers, diodes, semiconductors, scintillator, photodiodes, optical fiber dosimeters, solid-state detectors, resistive electrodes, and high-energy current detectors. For example, the air gap between opposing portions of a conductive element 30 surrounding a brachytherapy applicator 12 may be operable as an ion chamber. In some examples, the brachytherapy applicator 12 (e.g., an afterloader catheter) may be filled with a gas other than air.

[0032] In one example, the conductive element 30 includes a single thin film strip or microwire that is wrapped around (or deposited on) the surface of the brachytherapy applicator 12. In another example, the conductive element(s) 30 include multiple thin film strips or microwires providing multiple signals that are complementary to each other. In another example, the conductive element(s) 30 include a thin conductive layer (e.g., other than strips or wires) patterned onto the surface of the brachytherapy applicator 12. For instance, the conductive element(s) 30 may be segmented into complementary topologies, such as similar to those described by Z. Han, et al., in “Topological detector: measuring continuous dosimetric quantities with few-element detector array,” Phys. Med. Biol., 2016; 6HN403-N414, which is herein incorporated by reference in its entirety.

[0033] Additionally or alternatively, the conductive element(s) 30 may include a microtube arranged about the surface of the brachytherapy applicator 12 (i.e., a micro tube through which the brachytherapy applicator 12 extends). In these instances, when a source (e.g., dummy source, radiation source) is passed through the brachytherapy applicator 12 it will accumulate charge such as by friction with the walls of the brachytherapy applicator 12. When the source then passes through the conductive element 30 (e.g., a microtube or other conductive element or material) a current will be induced in the conductive element 30. This inducedcurrent may increase to a maximum value marking the moment the source entered or exited the conductive element 30.

[0034] Advantageously, the conductive element(s) 30 may also be surrounded by a larger diameter tube creating a miniaturized well-type ionization chamber surrounding the brachytherapy applicator 12, as indicated in FIG. IB. For instance, the conductive element 30 can be used as the inner electrode of the well-type ionization chamber, which is then surrounded by a second, outer electrode 32. The conductive element 30 and outer electrode 32 are separated by a gas-filled volume 34. The gas-filled volume 34 may be filled with a suitable gas that will be ionized when exposed to ionizing radiation from the radiation source. As a non-limiting example, the gas-filled volume 34 can be filled with a noble gas, such as argon, or a mixture of gases, such as argon mixed with methane. In some examples, the gas-filled volume 34 may be filled with ambient air. An electric field can be established between the conductive element 30 and outer electrode 32. For instance, the conductive element 30 can act as an anode and the outer electrode 32 can act as a cathode.

[0035] As described above, radiation impinging on the conductive element(s) 30 creates electrons, ions, or electron-holes and other charge carriers inside each section of the conductive element(s) 30. These charge carriers give rise to signal collected at the end of the conductive element(s), such as at the proximal end 14 of the brachytherapy applicator 12, via one or more data acquisition (“DAQ”) channels. The specific cross section (e.g., cross- sectional structure) through the conductive element(s) 30 may take various forms and configurations. For example, as described above, the conductive element(s) 30 can be structured such as in ion chamber, HEC detector, diode, or other solid state-based detector. The radiation source localization assembly 10 geometry is such that it both absorbs the radiation generated by the radiation source 20 (as it moves along the brachytherapy applicator 12) and transmits the measured signal data to the proximal end 14 of the brachytherapy applicator 12, where the signal data are collected by a DAQ system 22 in the form of current or voltage signals as a function of time. Advantageously, the detectors formed by the conductive element(s) 30 are semitransparent to radiation and in many instances minimally absorb the radiation while providing a meaningful electric signal that can be used to localize the radiation source.

[0036] In an example implementation where the brachytherapy applicator 12 is an afterloader catheter, the conductive element(s) 30 may include a microwire structure (e.g., one of the microwire structures illustrated in FIG. 2), which is wrapped around the afterloader catheter that allows brachytherapy source motion from a shielded storage device into patientanatomy. The position of a brachytherapy source in the catheter at any given time is dynamically changing to provide a specific distribution of radiation inside the patient. The wrapping of a single microwire around the catheter may be implemented as follows: the wire is wound around the catheter as in a spool N times and at M different locations along the catheter. The number of turns, N, and locations, M, can be selected to achieve a desired signal- to-noise ratio (“SNR”) and based on the specific motion of the brachytherapy source. For typical motions used in radiotherapy (e.g., HDR brachytherapy, LDR brachytherapy, etc.), the geometry can be optimized.

[0037] In use, the radiation source localization system 10 can provide real-time localization and strength of the source as a real-time feedback to the clinician team performing the procedure on patient, or to the team performing verification of equipment operation and dose distribution on phantoms. For example, based on spatial encoding of the microwire by wrapping it around the afterloader catheter, HDR source localization is possible because this encoding allows for clear identification of which loop of wire the HDR source is closest to it. From this identification, the position and radioactive strength of the HDR source can be subsequently determined. FIG. 3 illustrates an example of radiation source localization using a single wire measuring sequentially in four locations along the length of a brachytherapy applicator.

[0038] As described above, other possible configurations of wires with respect to the catheter or other radiation beam and sources than a single wire configuration are possible in order to detect spatiotemporal characteristics of the radiation source or beam. For instance, a dual wire spatial encoding (e.g., the dual wire configuration shown in FIG. 2) allows for reconstruction of the position of each source dwelling. In use, such a configuration can provide real-time quantification of the dose delivered by the radiation source at each dwelling position by detecting location and dwelling time with respect to the patient anatomy. This real-time quantification can be performed for pretreatment verification, quality assurance, and / or in-vivo dosimetry during treatment.

[0039] In addition to radiation source localization, the systems and methods described in the present disclosure may be used to extend beyond the source length, and may be used to provide a reading proportional to the source strength. In these instances, the disclosed systems and methods provide for daily verification of the decayed activity, which may be compared to the computed values from the treatment planning system and the treatment console system. For instance, source activity may be verified by measuring spatiotemporal signal data in a 4?rgeometry when the radiation source passes through the brachytherapy applicator. In these instances, the integral of the spatiotemporal signal data is proportional to the source strength.

[0040] In a non-limiting example study, a coaxial micro-wire was wound along the length of an autoloader catheter with several loops and straight sections along the catheter. Radiation from a radioactive seed induced electric currents inside the wire as the seed traveled along the length of the catheter. Current as a function of time was measured from tungsten core (50 pm) at 600 Hz. An external carbon electrode was deposited on 25 pm polymer sheath and was grounded. As a result of the looping geometry of the microwire, spatial localization of the brachytherapy source was derived from signal by a calibration procedure. The device was self- powered, no bias voltage was applied, and only passive reading of signals were detected when radiation was present. Tests were performed both with a single and dual-wires design (e.g. those shown in FIG. 2). The single wire configuration was tested by delivering a QA plan with 45 dwells position and 2.5 mm spacing with few induced shifts measured with and without a 1 nun induced shift. The dual wire configuration was tested by a plan with one dwell position near the double winding’s locations.

[0041] The signal of each single wire with the source approaching loop locations showed a Gaussian distribution with FWHM of 4.5mm + / - 0.2mm. The signal strength was proportional to the HDR source activity. The QA plan with 45 dwells with induced shifts of treatment lengths was delivered to the needle with single wire and four winding locations. The shifts were correctly identified and measured with 0.1 mm accuracy. In the dual wire configuration two signals si and s2 were acquired as a function of dwell position, x. A calibration was performed by computing a fit function C(x)=(sl(x)-s2(x)) / (sl(x)+s2(x)). The QA plan with one dwell was delivered to the needle with dual wires configuration and using the calibration function a shift from the expected source location was detected with 0.1 mm resolution.

[0042] This example study demonstrated the feasibility of Ir-192 (or other) HDR source localization with submillimeter precision along an afterloader catheter by a coaxial W micro-wire. The advantageous application of the sensor include: daily verification of the treatment length, QA of treatment plans, and in-vivo verification of the treatment delivery, among others. The device design allows for low-cost fabrication of disposable catheters during an implant. Since the device operates without any bias voltage, it is safe to use either on the patient skin surface or interstitially within the patient tissues.

[0043] Referring now to FIG. 4, a flowchart is shown as illustrating an example method for performing daily quality assurance (“QA”) using the radiation source localization systems described in the present disclosure. For example, daily QA can be performed on an afterloader, or other brachytherapy applicator, to confirm that the radiation sources are moving to the correct location and / or depth in the afterloader catheter, or other brachy therapy applicator.

[0044] The method includes accessing prior QA data for the brachytherapy applicator with a computer system, as indicated at step 402. The prior QA data include source activity and treatment length measurements made in a prior QA session. The prior QA data may be accessed with the computer system by retrieving the prior QA data from a memory' or other machine-readable data storage device or medium.

[0045] The brachytherapy sources (e.g., radioactive seeds, electronic brachytherapy sources) are then loaded into the brachytherapy applicator, as indicated at step 404, and moved into position for the daily QA, as indicated at step 406. For instance, moving the brachytherapy sources into position can include pushing the brachytherapy sources to a planned treatment length using one or more wires arranged in the brachytherapy applicator (e.g., afterloader catheters). The location of the brachytherapy sources are then measured based on a visual inspection made by a user (e.g., using a ruler or other measurement tool) or by measuring the length of wire used to push the brachytherapy sources into position, as indicated at step 408. The position of the brachytherapy sources are also measured using the radiation source localization system, as indicated at step 410. For instance, spatiotemporal signal data are measured while the brachytherapy sources are moved into position and these spatiotemporal signal data are processed by the computer system to determine the spatial location of the brachytherapy sources. When the brachytherapy sources include electronic brachytherapy sources, the radiation source localization system is used to monitor the spatial location of the electronic brachytherapy sources while the sources are turned on (i.e., while the sources are actively emitting radiation).

[0046] The manual measurements and the source localization measurements are then compared to provide a daily QA measurement for the brachytherapy applicator, as indicated at step 412. In some instances, the daily QA measurement can be compared to the prior QA data to assess any day-to-day changes in the radiation therapy system. The daily QA measurement data can be presented to a user with the computer system and / or stored for later use, as indicated at step 414. For example, the computer system can generate a report indicating whether the daily QA is passed or failed (e.g., based on whether the radiation source localization is shiftedoutside of acceptable limits). FIG. 5 illustrates an example of daily QA being performing using a radiation source localization system with dual wires at a selected treatment length of 1200 mm. The black line is the calibration curve, overlayed with the real-time signals from the two wires (sl,s2) processed as (s2-sl) / (sl+s2). The intersection of the two provides an immediate visual of the PASS / FAIL result of the daily QA.

[0047] Referring now to FIG. 6, a flowchart is shown as illustrating an example method for monitoring radiation treatment in real-time using the radiation source localization systems described in the present disclosure. For example, brachytherapy applicators with radiation source localization systems embedded therein can be used to monitor a brachytherapy treatment in real-time, providing the source locations, dwell times, and activities for each brachytherapy applicator.

[0048] The method includes positioning one or more brachytherapy sources (e.g., radioactive seeds, electronic brachytherapy sources) within one or more brachytherapy applicators, as indicated at step 602. The brachytherapy applicator(s) include conductive elements that form a radiation source localization system as described above. As the brachytherapy sources are moved within the brachytherapy applicator(s), spatiotemporal signal data are recorded with a computer system, as indicated at step 604. For instance, the spatiotemporal signal data may include current or voltage changes in the conductive elements caused by radiation emitted by the brachytherapy sources and impinging upon the sensing portion of the conductive elements.

[0049] The spatiotemporal signal data are then processed by the computer system to estimate a location of the brachytherapy sources within the brachytherapy applicators, as indicated at step 606. Using these location data, the radiation dose delivered to the patient can be computed and compared to the pre-treatment plan for verification, as indicated at step 608. The computer system may then generate a report that is displayed to a user, as indicated at step 610. The report can include real-time feedback about the radiation source localization, dwell times, and activity. In this way, a misadministration can be directly monitored, and a physician can be provided with the tools to plan the following fraction accordingly (e.g., add dose or remove dose to portions of the tumor and healthy tissues receiving radiation).

[0050] Referring now to FIG. 7, a flow chart is shown as illustrating an example method for localizing one or more brachy therapy applicators using the radiation source localization systems described in the present disclosure.

[0051] The brachytherapy applicators are positioned within a region in a patient that is to receive treatment. The method includes positioning one or more brachytherapy sources (e.g., radioactive seeds, electronic brachytherapy sources) within brachytherapy applicators, as indicated at step 702.

[0052] The brachytherapy applicator(s) include conductive elements that form a radiation source localization system as described above. As the brachytherapy sources are moved within the brachytherapy applicator(s), spatiotemporal signal data are recorded with a computer system, as indicated at step 704. For instance, the spatiotemporal signal data may include current or voltage changes in the conductive elements caused by radiation emitted by the brachytherapy sources and impinging upon the conductive elements. With the brachytherapy applicators positioned within the treatment region, a brachytherapy source moving in one applicator may be measured not only by that applicator, but also adjacent applicators. Based on these measurements, the locations of each brachytherapy applicator can be estimated, as indicated at step 706. In this way, the spatiotemporal signal data measured from adjacent brachytherapy applicators can be used to construct a three-dimensional representation of the applicator positioning. Thus, as indicated at step 708, a three-dimensional reconstruction of the brachytherapy applicator positions is generated from the spatiotemporal signal data measured by the various brachytherapy applicators.

[0053] The computer system may then generate a report that is displayed to a user, as indicated at step 710. The report can include a three-dimensional reconstruction of the positioning of the brachytherapy applicators within the treatment region, and may include a comparison of these locations with the treatment plan. In this way, the report can provide realtime feedback about whether the brachytherapy applicators are accurately positioned within the treatment region, or whether adjustment of their positioning is necessary to confirm with the treatment plan.

[0054] Additionally or alternatively, the report can indicate whether there is a mismatch between transfer tubes and brachytherapy applicators to fix their attachment. For example, the report can indicate whether a transfer tube from an afterloader is coupled to the incorrect afterloader catheter, such that the radiation source delivered from the afterloader would be positioned in the incorrect afterloader catheter within the patient. In these instances, a conductive element may be arranged at the entrance of the afterloader catheter (e.g., at the coupling between the afterloader catheter and the transfer tube). Based on this report, the mismatch can be identified and corrected. In this way. aside from source localization and dwelltime verification of an active source, the present disclosure provides a method for identifying errors in the connection of multiple catheters / applicators to the transfer tubes and. ultimately, to the afterloader. This method allows detection of errors during pretreatment checks preventing treatment misadministration.

[0055] In still other implementations, the report can indicate whether there is a blockage or other obstruction in the brachytherapy applicator. In these instances, a dummy (i.e., non-radioactive) source can be introduced into the brachytherapy applicator rather than an active (i.e., radioactive) source. As the dummy source moves through the brachytherapy applicator, mirror currents will be induced in the conductive element(s) by triboelectrically charging the dummy source as it moves through the brachytherapy applicator. In this way, the present disclosure provides a method for detecting the motion of an inactive dummy source sent by an afterloader prior to an active source, which can be used to verify catheter obstruction, or during a procedure. As mentioned, the location of the dummy source can be determined by measuring spatiotemporal signals based on triboelectric effects and motion of the electrically charged dummy source, or active source, within the brachytherapy applicator, which induces currents in the conductive element(s) surrounding the brachytherapy applicator. The timedependent response of the conductive element(s) to the moving dummy / active source can be correlated with the spatial position along a given brachytherapy applicator, based on which the active brachytherapy applicator can be unambiguously identified. The distance of the dummy / active source from the brachytherapy applicator entrance can also be determined from these spatiotemporal signal data based on the determined spatial position of the source relative to the spatial position of the conductive element(s) (e.g., a conductive element at the entrance of the brachytherapy applicator).

[0056] FIG. 8 shows an example of a system 800 for radiation source localization in accordance with some embodiments of the systems and methods described in the present disclosure. As shown in FIG. 8, a computing device 850 can receive one or more types of data (e.g., spatiotemporal signal data) from data source 802. In some embodiments, computing device 850 can execute at least a portion of a radiation source localization system 804 to localize a radiation source from data received from the data source 802. Additionally or alternatively, the radiation source localization system 804 can calculate dose from data received from the data source 802 and / or generate a two-dimensional or three-dimensional reconstruction of radiation source locations to confirm accurate positioning of radiation sourceswithin brachytherapy applicators, or to confirm accurate positioning of the brachytherapy applicators themselves.

[0057] Additionally or alternatively, in some embodiments, the computing device 850 can communicate information about data received from the data source 802 to a server 852 over a communication network 854, which can execute at least a portion of the radiation source localization system 804. In such embodiments, the server 852 can return information to the computing device 850 (and / or any other suitable computing device) indicative of an output of the radiation source localization system 804.

[0058] In some embodiments, computing device 850 and / or server 852 can be any suitable computing device or combination of devices, such as a desktop computer, a laptop computer, a smartphone, a tablet computer, a wearable computer, a server computer, a virtual machine being executed by a physical computing device, and so on. The computing device 850 and / or server 852 can also reconstruct images from the data.

[0059] In some embodiments, data source 802 can be any suitable source of data (e.g., measurement data), another computing device (e.g., a server storing measurement data), and so on. In some embodiments, data source 802 can be local to computing device 850. For example, data source 802 can be incorporated with computing device 850 (e.g., computing device 850 can be configured as part of a device for measuring, recording, estimating, acquiring, or otherwise collecting or storing data). As another example, data source 802 can be connected to computing device 850 by a cable, a direct wireless link, and so on. Additionally or alternatively, in some embodiments, data source 802 can be located locally and / or remotely from computing device 850, and can communicate data to computing device 850 (and / or server 852) via a communication network (e.g., communication network 854).

[0060] In some embodiments, communication network 854 can be any suitable communication network or combination of communication networks. For example, communication network 854 can include a Wi-Fi network (which can include one or more wireless routers, one or more switches, etc.), a peer-to-peer network (e.g., a Bluetooth network), a cellular network (e.g., a 3G network, a 4G network, etc., complying with any suitable standard, such as CDMA, GSM, LTE, LTE Advanced, WiMAX, etc.), other types of wireless network, a wired network, and so on. In some embodiments, communication netw ork 854 can be a local area network, a wide area network, a public network (e.g., the Internet), a private or semi-private network (e.g., a corporate or university intranet), any other suitable type of netw ork, or any suitable combination of networks. Communications links shown in FIG. 8can each be any suitable communications link or combination of communications links, such as wired links, fiber optic links, Wi-Fi links. Bluetooth links, cellular links, and so on.

[0061] Referring now to FIG. 9, an example of hardware 900 that can be used to implement data source 802, computing device 850, and server 852 in accordance with some embodiments of the systems and methods described in the present disclosure is shown.

[0062] As shown in FIG. 9, in some embodiments, computing device 850 can include a processor 902, a display 904, one or more inputs 906, one or more communication systems 908, and / or memory 910. In some embodiments, processor 902 can be any suitable hardware processor or combination of processors, such as a central processing unit (“CPU'’), a graphics processing unit (“GPU"), and so on. In some embodiments, display 904 can include any suitable display devices, such as a liquid crystal display (“LCD”) screen, a light-emitting diode (“LED”) display, an organic LED (“OLED”) display, an electrophoretic display (e.g., an “e- ink” display), a computer monitor, a touchscreen, a television, and so on. In some embodiments, inputs 906 can include any suitable input devices and / or sensors that can be used to receive user input, such as a keyboard, a mouse, a touchscreen, a microphone, and so on.

[0063] In some embodiments, communications systems 908 can include any suitable hardware, firmware, and / or software for communicating information over communication network 854 and / or any other suitable communication networks. For example, communications systems 908 can include one or more transceivers, one or more communication chips and / or chip sets, and so on. In a more particular example, communications systems 908 can include hardware, firmware, and / or software that can be used to establish a Wi-Fi connection, a Bluetooth connection, a cellular connection, an Ethernet connection, and so on.

[0064] In some embodiments, memory' 910 can include any suitable storage device or devices that can be used to store instructions, values, data, or the like, that can be used, for example, by processor 902 to present content using display 904, to communicate with server 852 via communications system(s) 908, and so on. Memory 910 can include any suitable volatile memory, non-volatile memory, storage, or any suitable combination thereof. For example, memory 910 can include random-access memory (“RAM”), read-only memory (“ROM”), electrically programmable ROM (“EPROM”), electrically erasable ROM (“EEPROM”), other forms of volatile memory, other forms of non-volatile memory, one or more forms of semi-volatile memory', one or more flash drives, one or more hard disks, one or more solid state drives, one or more optical drives, and so on. In some embodiments, memory 910 can have encoded thereon, or otherwise stored therein, a computer program for controllingoperation of computing device 850. In such embodiments, processor 902 can execute at least a portion of the computer program to present content (e.g., images, user interfaces, graphics, tables), receive content from server 852, transmit information to server 852, and so on. For example, the processor 902 and the memory 910 can be configured to perform the methods described herein (e.g., the method of FIG. 4, the method of FIG. 6, the method of FIG. 7).

[0065] In some embodiments, server 852 can include a processor 912. a display 914, one or more inputs 916, one or more communications systems 918, and / or memory 920. In some embodiments, processor 912 can be any suitable hardware processor or combination of processors, such as a CPU, a GPU, and so on. In some embodiments, display 914 can include any suitable display devices, such as an LCD screen, LED display, OLED display, electrophoretic display, a computer monitor, a touchscreen, a television, and so on. In some embodiments, inputs 916 can include any suitable input devices and / or sensors that can be used to receive user input, such as a keyboard, a mouse, a touchscreen, a microphone, and so on.

[0066] In some embodiments, communications systems 918 can include any suitable hardware, firmware, and / or software for communicating information over communication network 854 and / or any other suitable communication networks. For example, communications systems 918 can include one or more transceivers, one or more communication chips and / or chip sets, and so on. In a more particular example, communications systems 918 can include hardware, firmware, and / or software that can be used to establish a Wi-Fi connection, a Bluetooth connection, a cellular connection, an Ethernet connection, and so on.

[0067] In some embodiments, memory 920 can include any suitable storage device or devices that can be used to store instructions, values, data, or the like, that can be used, for example, by processor 912 to present content using display 914, to communicate with one or more computing devices 850, and so on. Memory 920 can include any suitable volatile memory, non-volatile memory, storage, or any suitable combination thereof. For example, memory 920 can include RAM, ROM, EPROM, EEPROM, other ty pes of volatile memory, other types of non-volatile memory, one or more types of semi-volatile memory, one or more flash drives, one or more hard disks, one or more solid state drives, one or more optical drives, and so on. In some embodiments, memory 920 can have encoded thereon a server program for controlling operation of server 852. In such embodiments, processor 912 can execute at least a portion of the server program to transmit information and / or content (e.g., data, images, a user interface) to one or more computing devices 850, receive information and / or content from oneor more computing devices 850, receive instructions from one or more devices (e.g., a personal computer, a laptop computer, a tablet computer, a smartphone), and so on.

[0068] In some embodiments, the server 852 is configured to perform the methods described in the present disclosure. For example, the processor 912 and memory 920 can be configured to perform the methods described herein (e.g., the method of FIG. 4, the method of FIG. 6, the method of FIG. 7).

[0069] In some embodiments, data source 802 can include a processor 922, one or more data acquisition systems 924, one or more communications systems 926, and / or memory 928. In some embodiments, processor 922 can be any suitable hardware processor or combination of processors, such as a CPU, a GPU, and so on. In some embodiments, the one or more data acquisition systems 924 are generally configured to acquire spatiotemporal signal data measured from the conductive element(s) 30 of the radiation source localization assembly 10. Additionally or alternatively, in some embodiments, the one or more data acquisition systems 924 can include any suitable hardware, firmware, and / or software for coupling to and / or controlling operations of the data acquisition channels recording the spatiotemporal signal data measured from the conductive element(s) 30 of the radiation source localization assembly 10. In some embodiments, one or more portions of the data acquisition system(s) 924 can be removable and / or replaceable.

[0070] Note that, although not shown, data source 802 can include any suitable inputs and / or outputs. For example, data source 802 can include input devices and / or sensors that can be used to receive user input, such as a keyboard, a mouse, a touchscreen, a microphone, a trackpad, a trackball, and so on. As another example, data source 802 can include any suitable display devices, such as an LCD screen, an LED display, an OLED display, an electrophoretic display, a computer monitor, a touchscreen, a television, etc., one or more speakers, and so on.

[0071] In some embodiments, communications systems 926 can include any suitable hardware, firmware, and / or software for communicating information to computing device 850 (and, in some embodiments, over communication network 854 and / or any other suitable communication networks). For example, communications systems 926 can include one or more transceivers, one or more communication chips and / or chip sets, and so on. In a more particular example, communications systems 926 can include hardware, firmware, and / or software that can be used to establish a wired connection using any suitable port and / or communication standard (e.g., VGA, DVI video, USB, RS-232, etc ), Wi-Fi connection, a Bluetooth connection, a cellular connection, an Ethernet connection, and so on.

[0072] In some embodiments, memory' 928 can include any suitable storage device or devices that can be used to store instructions, values, data, or the like, that can be used, for example, by processor 922 to control the one or more data acquisition systems 924, and / or receive data from the one or more data acquisition systems 924; to generate images from data; present content (e.g., data, images, a user interface) using a display; communicate with one or more computing devices 850; and so on. Memory 928 can include any suitable volatile memory, non-volatile memory, storage, or any suitable combination thereof. For example, memory 928 can include RAM, ROM, EPROM, EEPROM, other types of volatile memory, other ty pes of non-volatile memory7, one or more types of semi-volatile memory, one or more flash drives, one or more hard disks, one or more solid state drives, one or more optical drives, and so on. In some embodiments, memory- 928 can have encoded thereon, or otherwise stored therein, a program for controlling operation of data source 802. In such embodiments, processor 922 can execute at least a portion of the program to generate images, transmit information and / or content (e.g., data, images, a user interface) to one or more computing devices 850, receive information and / or content from one or more computing devices 850, receive instructions from one or more devices (e.g., a personal computer, a laptop computer, a tablet computer, a smartphone, etc.), and so on.

[0073] In some embodiments, any suitable computer-readable media can be used for storing instructions for performing the functions and / or processes described herein. For example, in some embodiments, computer-readable media can be transitory or non-transitory. For example, non-transitory computer-readable media can include media such as magnetic media (e.g., hard disks, floppy disks), optical media (e.g., compact discs, digital video discs, Blu-ray discs), semiconductor media (e.g., RAM, flash memory-, EPROM, EEPROM), any suitable media that is not fleeting or devoid of any semblance of permanence during transmission, and / or any suitable tangible media. As another example, transitory computer- readable media can include signals on networks, in wires, conductors, optical fibers, circuits, or any suitable media that is fleeting and devoid of any semblance of permanence during transmission, and / or any suitable intangible media.

[0074] As used herein in the context of computer implementation, unless otherwise specified or limited, the terms “component,” “system,” “module,” “framework,” and the like are intended to encompass part or all of computer-related systems that include hardware, software, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a processor device, a process being executed(or executable) by a processor device, an object, an executable, a thread of execution, a computer program, or a computer. By way of illustration, both an application running on a computer and the computer can be a component. One or more components (or system, module, and so on) may reside within a process or thread of execution, may be localized on one computer, may be distributed between two or more computers or other processor devices, or may be included within another component (or system, module, and so on).

[0075] In some implementations, devices or systems disclosed herein can be utilized or installed using methods embodying aspects of the disclosure. Correspondingly, description herein of particular features, capabilities, or intended purposes of a device or system is generally intended to inherently include disclosure of a method of using such features for the intended purposes, a method of implementing such capabilities, and a method of installing disclosed (or otherwise known) components to support these purposes or capabilities. Similarly, unless otherwise indicated or limited, discussion herein of any method of manufacturing or using a particular device or system, including installing the device or system, is intended to inherently include disclosure, as embodiments of the disclosure, of the utilized features and implemented capabilities of such device or system.

[0076] The present disclosure has described one or more preferred embodiments, and it should be appreciated that many equivalents, alternatives, variations, and modifications, aside from those expressly stated, are possible and within the scope of the invention.

Claims

CLAIMS1. A radiation source localization system, comprising: a brachytherapy applicator extending along a length from a proximal end to a distal end and having an internal lumen extending therethrough; and at least one conductive element coupled to the brachytherapy applicator to measure radiation emitted by a radiation source moving through the internal lumen of the brachytherapy applicator.

2. The radiation source localization system of claim 1, further comprising a computer system in communication with the at least one conductive element to: receive spatiotemporal signal data from the radiation measured by the at least one conductive element; and determine a location of the radiation source within the internal lumen of the brachytherapy applicator from the spatiotemporal signal data.

3. The radiation source localization system of claim 1, wherein the at least one conductive element comprises a single wire coupled to a surface of the brachytherapy applicator.

4. The radiation source localization system of claim 3, wherein the single wire is looped around a circumference of the brachytherapy applicator N times at each of a plurality of locations along the length of the brachytherapy applicator.

5. The radiation source localization system of claim 4, comprising a second wire coupled to the surface of the brachytherapy applicator.

6. The radiation source localization system of claim 5, wherein the second wire is looped around the circumference of the brachytherapy applicator N times at each of a plurality of second locations along the length of the brachytherapy applicator.

7. The radiation source localization system of claim 1, wherein the at least one conductive element comprises a conductive material deposited on a surface of the brachytherapy applicator.

8. The radiation source localization system of claim 7, wherein the conductive material comprises at least one of a conductive pattern of electrodes or an insulating pattern of electrodes.

9. The radiation source localization system of claim 7, wherein the at least one conductive element comprises a thin film.

10. The radiation source localization system of claim 1, wherein the at least one conductive element comprises at least one microstrip conductor coupled to a surface of the brachytherapy applicator.

11. The radiation source localization system of claim 1 , wherein the brachytherapy applicator comprises a needle composed of a conductive material and the at least one conductive element comprises a portion of the needle having some of the conductive material removed.

12. The radiation source localization system of claim 11, wherein the portion of the brachytherapy needle comprises a portion of the brachytherapy needle that is etched to remove the conductive material.

13. A method for daily quality assurance (QA) of a brachytherapy system, comprising:(a) arranging a brachytherapy source within a brachytherapy applicator at a predetermined treatment length;(b) acquiring spatiotemporal signal data using a conductive element coupled to the brachytherapy applicator while the brachytherapy source is emitting radiation at the predetermined treatment length along the brachytherapy applicator;(c) determining a location of the brachytherapy source from the spatiotemporal signal data; and(d) generating daily QA data by comparing the determined location to the predetermined treatment length.

14. The method of claim 13, wherein the brachytherapy source comprises one of a radioactive seed or an electronic brachytherapy source.

15. A method for localizing a radiation source during treatment, comprising:(a) arranging a brachytherapy source within a brachytherapy applicator;(b) acquiring spatiotemporal signal data using a conductive element coupled to the brachytherapy applicator while the brachytherapy source is emitting radiation and moved within the brachytherapy applicator to a treatment position;(c) determining a location of the brachytherapy source from the spatiotemporal signal data; and(d) generating a report indicating the location of the brachytherapy source within the brachytherapy applicator.

16. The method of claim 15, further comprising computing a dose delivered at the treatment position based on the determined location of the brachytherapy source.

17. The method of claim 15, further comprising verifying activity of the brachytherapy source by measuring the spatiotemporal signal data in a 4n geometry and computing an integral of the spatiotemporal signal data, wherein the integral of the spatiotemporal signal data is proportional to the activity of the brachytherapy source.

18. The method of claim 15, wherein the brachytherapy source comprises one of a radioactive seed or an electronic brachytherapy source.

19. The method of claim 15, wherein the brachytherapy applicator is coupled to a transfer tube and the report indicates whether the brachytherapy applicator is coupled to a correct transfer tube based on whether the location of the brachytherapy source is correct relative to a treatment plan.

20. The method of claim 19, wherein the report is generated as a pretreatment check relative to the treatment plan.

21. The method of claim 19, wherein the report is generated during treatment to verify the location of the brachytherapy source relative to the treatment plan.

22. The method of claim 19, wherein the conductive element is coupled to the brachytherapy applicator near a coupling between the brachytherapy applicator and the transfer tube.

23. The method of claim 15, wherein the brachytherapy source is a dummy source that does not emit radiation and the spatiotemporal signal data are acquired by measuring mirror currents induced in the conductive element by triboelectrically charging the dummy source as it moves through the brachytherapy applicator.

24. The method of claim 23, wherein the report indicates whether the brachytherapy applicator is clear of obstructions.

25. The method of claim 15, wherein the report indicates a distance of the brachytherapy source along a length of the brachytherapy applicator.

26. A method for localizing a plurality' of brachytherapy applicators, comprising:(a) arranging at least one brachytherapy source within at least one of a plurality of brachytherapy applicators positioned within a treatment region of a patient;(b) acquiring spatiotemporal signal data for each of the plurality' of brachytherapy applicators using a conductive element coupled to each of the plurality of brachytherapy applicators while the at least one brachytherapy source is emitting radiation within the at least one of the plurality of brachytherapy applicators;(c) determining a location of each of the plurality of brachytherapy applicators from the spatiotemporal signal data; and(d) generating a report indicating the location of each of the plurality of brachytherapy applicators.

27. The method of claim 26, wherein generating the report comprises generating, based on the spatiotemporal signal data, a three-dimensional reconstruction indicating the location of each of the plurality of brachytherapy applicators.

28. The method of claim 26, comprising determining a location of the at least one brachytherapy source from the spatiotemporal signal data, and wherein the report also indicates a location of the at least one brachytherapy source.

29. The method of claim 26, wherein the at least one brachytherapy source comprises at least one of a radioactive seed or an electronic brachytherapy source.

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