Method and device for controlling radiation source exposure

Abstract

The present invention relates to an exemplary remote control device for a radiation source, wherein the remote control device comprises: a front cable section configured to extend into and through the radiation source housing to expose the radiation source to the outside of the radiation source housing, and to retract into and through the radiation source housing to retract the radiation source into the radiation source housing; a drive cable section coupled to the front cable section; and a drive gear configured to extend the front cable by driving the drive cable section in a first direction and to retract the front cable section by driving the drive cable section in a second direction, wherein the front cable section has a smooth outer surface having less friction than the drive cable section while traversing the radiation source housing.

Description

Technology Field

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 106,664, filed October 28, 2020, under the title “METHODS AND APPARATUS FOR CONTROL OF RADIOGRAPHIC SOURCE EXPOSURE”, and U.S. Patent Application No. 17 / 500,617, filed October 13, 2021. The full contents of U.S. Provisional Application No. 63 / 106,664 and U.S. Patent Application No. 17 / 500,617 are expressly incorporated herein by reference.

[0002] The present disclosure generally relates to radiography, and more specifically to a method and apparatus for controlling radiation source exposure. Background Technology

[0003] Industrial radiography is commonly used to generate images of objects that would otherwise be difficult to inspect, and involves exposing a source of high-energy radiation (e.g., gamma rays) to form a radiographic image and collecting the transmitted and / or reflected rays. When not in use, gamma ray sources, such as radioisotopes, are stored in shielding devices.

[0004] A method and apparatus for controlling radiation source exposure are disclosed as substantially illustrated by at least one of the attached drawings and described in relation thereto and more fully described in the claims. Brief explanation of the drawing

[0005] Such features, aspects, and advantages of the present disclosure, as well as other features, aspects, and advantages, will become more apparent when reading the following detailed description with reference to the accompanying drawings, in which the same reference numerals throughout the drawings indicate the same parts. FIGS. 1a and FIGS. 1b illustrate an exemplary radiographic system that provides radiation for radiography according to an embodiment of the present disclosure. FIG. 2 illustrates a cross-section of a conventional radiation source and a radiation source housing in which a portion of the radiation source housing undergoes undesirable mechanical wear during use. FIGS. 3a and 3b illustrate an exemplary radiographic system that can be used to implement the radiographic system of FIGS. 1a and 1b, wherein a remote control device used to control the exposure of a radiation source causes the radiation source housing to undergo substantially less wear than in a conventional system. FIG. 4 illustrates a cross-section of the exemplary front cable section of FIG. 3a and FIG. 3b. FIG. 5a illustrates an exemplary manual remote control device configured to implement the radiography system of FIG. 3a and FIG. 3b. FIG. 5b illustrates in more detail the exemplary manual remote control device of FIG. 5a, which includes a window that allows the status of the cable connector of FIG. 3a and FIG. 3b to be observed without exposing the cable connector to the outside of the manual remote control device. FIG. 6 is a flowchart illustrating an exemplary method that can be performed to control the exposure of a radiation source using the system of FIG. 3a and FIG. 3b. The drawings are not necessarily drawn to scale. Where appropriate, similar or identical reference numerals are used to refer to similar or identical components. Specific details for implementing the invention

[0006] For the purpose of facilitating understanding of the principles of the claimed technology and presenting the best currently understood mode of operation, specific language will be used below to refer to and describe the embodiments illustrated in the drawings. Nevertheless, it will be understood that this is not intended to limit the scope of the claimed technology, and that such changes and other variations in the illustrated devices, and such other uses of the principles of the claimed technology illustrated therein, are considered to be common to those skilled in the art regarding the claimed technology.

[0007] An exemplary remote control device for a radiation source disclosed comprises: a front cable section configured to extend into and through the radiation source housing to expose the radiation source to the outside of the radiation source housing, and to retract into and through the radiation source housing to retract the radiation source into the radiation housing; a drive cable section coupled to the front cable section; and a drive gear configured to extend the front cable section by driving the drive cable section in a first direction and retract the front cable section by driving the drive cable section in a second direction, wherein the front cable section has a smooth outer surface having less friction than the drive cable section while traversing the radiation source housing.

[0008] Some exemplary remote control devices further include a cable connector that mechanically couples a forward cable section to a drive cable section. In some exemplary remote control devices, the forward cable section and the drive cable section each have a length such that the cable connector and the forward cable section do not come into contact with the drive gear. In some exemplary remote control devices, the forward cable section and the drive cable section each have a length such that the cable connector does not enter the radiation source housing. Some exemplary remote control devices further include a drive gear housing configured to accommodate a drive gear, and the drive gear housing has a window configured to allow the cable connector to be seen when the forward cable section is in a predetermined position inside the drive gear housing. In some exemplary remote control devices, the cable connector is configured to be detachable from at least one of the forward cable section or the drive cable section.

[0009] In some exemplary remote control devices, the forward cable section and the drive cable section each have a length such that the drive cable section does not enter the radiation source housing. In some exemplary remote control devices, the forward cable section comprises at least one of semi-rigid spring steel, a spiral-wound cable, a close-wound cable, or a compression wire rope. In some exemplary remote control devices, the forward cable section comprises an outer coating configured to have a friction coefficient smaller than the critical friction coefficient. In some exemplary remote control devices, the outer coating comprises at least one of polytetrafluoroethylene (PTFE), molybdenum disulfide (MoS2) lubricant, graphite, a fluoropolymer-based coating of the trade name Xylan®, ethylene chlorotrifluoroethylene (ECTFE), a lubricant of the trade name Canadize, or parylene.

[0010] Some exemplary remote control devices further include a handle configured to actuate a drive gear. Some exemplary remote control devices further include a motor configured to actuate a drive gear. Some exemplary remote control devices further include a control conduit configured to cover a portion of the drive cable section and a forward cable section located between the drive gear and the radiation source housing; and a source connector configured to secure the control conduit to the radiation source housing. In some exemplary remote control devices, the forward cable section is configured to cross an S-shaped source tube inside the radiation source housing to pass through the S-shaped source tube and push the radiation source to the outlet of the S-shaped source tube.

[0011] An exemplary method for controlling radiation source exposure disclosed comprises the steps of: mechanically coupling a forward cable section to a radiation source inside a radiation source housing; and extending a radiation source from inside the radiation source housing to outside the radiation source housing to expose the radiation source by driving the forward cable section using a driving cable section, wherein the forward cable section has a smooth outer surface having less friction than the driving cable section while traversing the radiation source housing.

[0012] In some exemplary methods, the step of extending the radiation source includes rotating a drive gear in a first direction to drive a drive cable section to drive a forward cable section. Some exemplary methods further include retracting the radiation source into the radiation source housing by rotating a drive gear in a second direction to drive the drive cable section to retract the radiation source through the forward cable section and the drive cable section. Some exemplary methods further include attaching the forward cable section to the drive cable section via a cable connector. Some exemplary methods further include attaching the forward cable section to the radiation source. In some exemplary methods, the step of extending the radiation source ends before the drive cable section enters the radiation source housing.

[0013] FIGS. 1a and FIGS. 1b illustrate an exemplary radiographic system (100) that provides radiation for radiography. The radiographic system (100) of FIG. 1 includes a radiation source (102) housed inside a radiation source housing (104). The exemplary radiation source (102) is a mass of radioactive material that emits radiation (e.g., X-rays and / or gamma rays) due to decay.

[0014] The radiation source housing (104) includes an S-shaped source tube (106) inside a shielding section (108). The source tube (106) provides a passage for a radiation source (102) that is exposed outside the shielding section (108) and retracts into a shielded position inside the shielding section (108). FIG. 1a shows a radiation source (102) in a shielded position, and FIG. 1b shows a radiation source (102) in an exposed position.

[0015] To control the position of the radiation source (102), the radiation source housing (104) enables the connection of a control cable (110) to the radiation source (102) for the exposure and retraction of the radiation source (102). The control cable (110) is physically attached to or connected to a pigtail connector (112) that is physically coupled to the radiation source (102).

[0016] When engaged, the control cable (110) is controlled to extend into and through the source tube (106) to push the radiation source (102) to an exposed position outside the radiation source housing (104). Conversely, the control cable (110) is retracted to pull the radiation source (102) back into the shielded position inside the source tube (106) from the exposed position, at which point the control cable (110) can be separated from the radiation source (102).

[0017] In the system (100) of FIG. 1, the exposure position of the radiation source (102) can be controlled by a guide tube (114), and as the radiation source (102) is pushed by a control cable (110), the radiation source (102) moves through the guide tube (114). The control cable (110) has sufficient column strength to push the radiation source (102) through the source tube (106) and through the guide tube (114).

[0018] The control cable (110) is controlled by a remote control device (116). The remote control device (116) is physically engaged with the control cable (110) to advance or retract the control cable (110) relative to the remote control device (116).

[0019] FIG. 2 illustrates a cross-section of a conventional radiation source shielding assembly (204) in which a portion of the radiation source shielding assembly (204) undergoes undesirable mechanical wear during use. As illustrated in FIG. 2, the source tube (106) extends through the shielding portion (108) in an S-shaped curve. Consequently, there are multiple points (206) in the source tube (106) where significant friction occurs between the control cable (110) and the source tube (106) when the conventional control cable (210) advances or retracts through the source tube (106).

[0020] Conventional control cables (also referred to as drive cables) are not manufactured for the purpose of operating the source in radiography applications. Although radiography systems are designed to be sealed during assembly, they are not effectively sealed during installation, failure, and / or improper storage, which allows the radiography system to be exposed to contaminants (e.g., dust, sand, water) that were not considered in the design.

[0021] The conventional control cable (210) is a flexible steel cable having a helical outer winding. The helical outer winding allows the remote control device (116) to engage with the conventional control cable (210) and to advance and retract the cable (210) with high precision. However, if not properly maintained, the helical outer winding can cause significant friction and / or abrasion at a point (206) inside the source tube (106) when the conventional control cable (210) moves in an S-shaped curve. Such friction and / or abrasion can cause premature wear of the source tube (106), thereby reducing the effective life of the radiation source shielding assembly (204) and / or radiation source housing (104). If sufficient cable lubrication is not provided in the control cable (110), the risk of damage to the control cable (110) may increase due to friction and / or abrasion.

[0022] FIGS. 3a and 3b illustrate an exemplary radiographic system (300) that can be used to implement the radiographic system (100) of FIGS. 1a and 1b, and a remote control device (302) used to control the exposure of a radiation source (102) causes the radiation source housing (104) to undergo substantially less wear than a conventional system (e.g., the conventional system of FIG. 2).

[0023] Unlike the conventional control cable (210) of FIG. 2, the exemplary remote control device (302) of FIG. 3a includes a forward cable section (304) configured to extend into and through a radiation source housing (104), and a driving cable section (306) coupled to the forward cable section (304).

[0024] The drive cable section (306) may be similar or identical to the conventional control cable (210) of FIG. 2. In contrast, the forward cable section (304) has a smooth outer surface so that the forward cable section (304) has less friction than the drive cable section (306) (or the conventional control cable (210)) while traversing the radiation source housing (104) (e.g., passing through the source tube (106)). FIG. 4 illustrates a cross-section of the exemplary forward cable section (304) of FIG. 3a and FIG. 3b. For example, the forward cable section (304) may include an inner column (402) manufactured using one or more of a semi-rigid spring material, a spiral wound cable, a closed wound cable, and / or a compression wire rope. The inner column (402) may be a metal, polymer, and / or any other material capable of linear operation while maintaining sufficient strength in a radioactive environment for at least a critical lifetime and having acceptable flexibility.

[0025] The inner column (402) may be wrapped, coated, or otherwise covered by an outer cover (404) (e.g., coating, physical cover, wrap, etc.) having a friction coefficient smaller than the critical friction coefficient. In some examples, the outer coating is a tape, wrap, coating and / or other cover and may be made of polytetrafluoroethylene (PTFE), molybdenum disulfide (MoS2) lubricant (sold by DuPont under the trade name MolyKote®), graphite, a fluoropolymer-based coating agent under the trade name Xylan® (sold by Whitford Corporation), ethylene chlorotrifluoroethylene (ECTFE), a lubricant under the trade name Canadize (sold by General Magnaplate), and / or parylene. However, any other suitable material may be used as a coating. In some examples, the material may be selected or modified to visually indicate wear of the coating on the front cable section (304). As a result of less friction, the forward cable section (304) can substantially reduce or eliminate wear and / or abrasion on the source tube (106) while advancing or retracting the radiation source (102).

[0026] The drive cable section (306) engages with the drive gear (308) of the remote control device (302). The drive gear (308) extends the front cable section (304) (and radiation source (102)) by driving the drive cable section (306) in a first direction and retracts the front cable section (304) (and radiation source (102)) by driving the drive cable section in a second direction, while the front cable section (304) does not come into contact with the drive gear (308).

[0027] The cable connector (310) mechanically couples the front cable section (304) to the drive cable section (306). In the examples of FIGS. 3a and 3b, only the drive cable section (306) engages with the drive gear (308). The front cable section (304) and the drive cable section (306) each have a length such that the cable connector (310) and the front cable section (304) do not come into contact with the drive gear (308). Similarly, the front cable section (304) and the drive cable section (306) each have a length such that the cable connector (310) and the drive cable section (306) do not enter the radiation source housing (104) and / or the source tube (106).

[0028] An exemplary remote control device (302) includes a control conduit (312) for covering a front cable section (304) and / or a drive cable section (306) between at least a drive gear (308) and a radiation source housing (104). In the examples of FIGS. 3a and 3b, the control conduit (312) is coupled to a conduit connector (314) that secures the control conduit (312) to the radiation source housing (104) and aligns the outlet of the control conduit (312) with the inlet of the corresponding radiation source housing (104). For example, the front cable section (304) and the front connector (318) may be connected to the radiation source (102) via a pigtail connector (316) and a pigtail cable (320). Once connected, the conduit connector (314) can be connected and secured to the radiation source housing (104), and the front cable section (304) can be physically attached to the pigtail cable (320) which is secured to the radiation source (102). In some examples, the pigtail cable (320) is made of a structure identical or similar to the front cable section (304) or identical or similar to the drive cable section (306).

[0029] An exemplary conduit connector (314) can be implemented using a conventional connector used in the Sentinel 880 gamma ray source projection system sold by QSA Global, Inc., Burlington, Massachusetts.

[0030] The disclosed exemplary remote control device including a forward cable section (304) has the advantage that, compared to a conventional control cable (210), the forward cable section (304) reduces overall sliding friction with respect to the source tube (106). The reduction in sliding friction extends the effective life of the source tube (106) by extending the time and usage required to pass through the source tube (106) and wear into the shielding (108) (which may be depleted uranium) adjacent to the source tube (106). Such an increase in the effective life of the source tube (106) is a significant financial benefit to the owner of the system.

[0031] FIG. 5a illustrates an exemplary manual remote control device (500) configured to implement the radiographic system of FIG. 3a and FIG. 3b. The manual remote control device (500) includes a pistol-style housing (502) that accommodates a drive gear (308). The housing (502) includes a grip portion (504) that can be grasped by an operator of the remote control device (500) when a handle (506) attached to the drive gear (308) is rotated. When the handle (506) is rotated in the direction of exposure (e.g., forward), the drive gear (308) advances the drive cable section (306) toward the conduit connector (314), which causes the forward cable section (305) to similarly advance the radiation source (102) and push the radiation source (102). Conversely, rotating the handle (506) in the retracting direction (opposite to the exposure direction) causes the drive gear (308) to retract the drive cable section (306) away from the conduit connector (314), which pulls the forward cable section (304) to retract the radiation source (102) toward a shielded or storage position inside the source tube (106).

[0032] FIG. 5b illustrates in more detail the exemplary manual remote control device (500) of FIG. 5a, which includes a window (510) that allows the status of the cable connector of FIG. 3a and FIG. 3b to be observed without exposing the cable connector to the outside of the manual remote control device.

[0033] FIGS. 5a and 5b illustrate a pistol-style housing, but a reel-style housing and / or any other type of housing may be used. Additionally or alternatively, the drive gear (308) may be replaced with other types of actuators and / or drive interfaces to drive the drive cable section (306) and the front cable section (304). In some examples, the drive gear (308) (or other drive interface) may be operated automatically instead of being operated manually via a handle.

[0034] FIG. 6 is a flowchart illustrating an exemplary method (600) that can be performed to control the exposure of a radiation source (102) using the system of FIG. 3a and FIG. 3b. The method (600) is disclosed below with reference to specific applicable elements, but local regulations may require additional measures or steps, such as (but not limited to) a definite investigation of radiation levels before and / or after the exposure of the radioactive source, along with the steps disclosed.

[0035] In block 602, the front cable section (304) is mechanically coupled to the radiation source (102) through a conduit connection. For example, the front cable section (304) can be mechanically attached to the pigtail connector (316) through the front connector (318), and / or the control conduit (312) can be coupled to the radiation source housing (104).

[0036] In block 604, the drive gear (308) is rotated in the forward direction to advance the drive cable section (306). As a result of advancing the drive cable section (306), the front cable section (304) and the radiation source (102) are returned to the storage position inside the shield (108).

[0037] In block 606, a radiation source (102) is exposed for a critical time period to take one or more radiation images (e.g., through a radiation detector or imaging device).

[0038] In block 608, the drive gear (308) is rotated in the retracting direction to retract the drive cable section (306). As a result of retracting the drive cable section (306), the front cable section (304) and the radiation source (102) are retracted to secure the radiation source (102).

[0039] In block 610, it is determined whether the radiation source (102) is fixed in a shielded position. If the radiation source (102) is not fixed in a shielded position (block 610), the method (600) returns to block 608 to continue the retreat.

[0040] When the radiation source (102) is located in a shielded position (block 610), in block 612, the front cable section (304) can be separated from the radiation source (102). Then, the exemplary method (600) is terminated.

[0041] As used herein, the expression “and / or” means one or more of the items in the list linked by the expression “and / or”. In one example, “x and / or y” means any element of the three sets of elements {(x), (y), (x, y)}. In other words, “x and / or y” means “one or both of x and y”. In another example, “x, y and / or z” means any element of the seven sets of elements {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, “x, y and / or z” means “one or more of x, y, and z”. As used herein, the expression “exemplary” means to function as a non-limiting example, illustration, or description. Expressions such as “e.g.” and “e.g.” as used herein disclose a list of one or more non-limiting examples, illustrations, or descriptions. As used herein, a circuit is “operable” to perform a function, regardless of whether the performance of the function is disabled or not (e.g., user-configurable settings, factory trim, etc.), provided that the circuit includes the essential hardware and code (if necessary) for performing the function.

[0042] Although the method and / or system of the present invention has been described with reference to specific embodiments, those skilled in the art will understand that various modifications may be made and equivalents substituted without departing from the scope of the method and / or system of the present invention. For example, blocks and / or components of the disclosed examples may be combined, divided, rearranged, and / or otherwise modified. Furthermore, numerous modifications may be made to fit specific situations or materials to the teachings of the present disclosure without departing from the scope of the present disclosure. Accordingly, the method and / or system is not limited to the specific embodiments disclosed. Instead, the method and / or system may include all embodiments that fall within the scope of protection of the appended claims, both literally and in accordance with the doctrine of equivalents.

Claims

Claim 1 A remote control device for a radiation source, comprising: a front cable section configured to be detachably coupled to the radiation source through a connector, extend into and through the radiation source housing to expose the radiation source to the outside of the radiation source housing, and retract into and through the radiation source housing to retract the radiation source into the radiation source housing; a drive cable section coupled to the front cable section; a cable connector configured to mechanically couple the front cable section to the drive cable section; and a drive gear configured to extend the front cable by driving the drive cable section in a first direction and retract the front cable section by driving the drive cable section in a second direction, wherein the front cable section has a smooth outer surface to have less friction than the drive cable section while traversing the radiation source housing. Claim 2 A remote control device according to claim 1, wherein the front cable section and the drive cable section each have a length such that the cable connector and the front cable section do not come into contact with the drive gear. Claim 3 A remote control device according to claim 1, wherein the front cable section comprises at least one of semi-rigid spring steel, spiral wound cable, close-wound cable, or compression wire rope. Claim 4 A remote control device according to claim 1, wherein the front cable section comprises an outer coating configured to have a friction coefficient smaller than a critical friction coefficient. Claim 5 A remote control device according to claim 4, wherein the outer coating comprises at least one of polytetrafluoroethylene (PTFE), molybdenum disulfide (MoS2) lubricant, graphite, a fluoropolymer-based coating of the trade name Xylan®, ethylene chlorotrifluoroethylene (ECTFE), a lubricant of the trade name Canadize, or parylene. Claim 6 A remote control device according to claim 1, further comprising a handle configured to operate the drive gear. Claim 7 A remote control device according to claim 1, further comprising a motor configured to operate the drive gear. Claim 8 A remote control device according to claim 1, further comprising: a control conduit configured to cover a portion of the front cable section and the drive cable section located between the drive gear and the radiation source housing; and a source connector configured to secure the control conduit to the radiation source housing. Claim 9 A remote control device according to claim 1, wherein the front cable section is configured to cross the S-shaped source tube inside the radiation source housing in order to pass through the S-shaped source tube and push the radiation source to the outlet of the S-shaped source tube. Claim 10 A remote control device for a radiation source, comprising: a front cable section configured to be detachably coupled to the radiation source via a connector, extend into and through the radiation source housing to expose the radiation source to the outside of the radiation source housing, and retract into and through the radiation source housing to retract the radiation source into the radiation source housing; a drive cable section coupled to the front cable section, wherein the front cable section and the drive cable section each have a length such that the drive cable section does not enter the radiation source housing; and a drive gear configured to extend the front cable by driving the drive cable section in a first direction and retract the front cable section by driving the drive cable section in a second direction, wherein the front cable section has a smooth outer surface to have less friction than the drive cable section while traversing the radiation source housing. Claim 11 A remote control device according to claim 10, further comprising a cable connector configured to mechanically couple the front cable section to the drive cable section. Claim 12 A remote control device according to claim 11, further comprising a drive gear housing configured to accommodate the drive gear, wherein the drive gear housing has a window configured to allow the cable connector to be seen when the front cable section is in a predetermined position inside the drive gear housing. Claim 13 A remote control device according to claim 11, wherein the cable connector is configured to be detachable from at least one of the front cable section or the drive cable section. Claim 14 A method for controlling radiation source exposure, comprising: a step of mechanically coupling a front cable section to a radiation source inside a radiation source housing; and a step of extending the radiation source from inside the radiation source housing to outside the radiation source housing to expose the radiation source by driving the front cable section using a driving cable section, wherein the front cable section has a smooth outer surface having less friction than the driving cable section while crossing the radiation source housing, and the step of extending the radiation source is terminated before the driving cable section enters the radiation source housing. Claim 15 In claim 14, the step of extending the radiation source comprises rotating a drive gear in a first direction to drive the drive cable section to drive the forward cable section. Claim 16 A method according to claim 15, further comprising retracting the radiation source into the radiation source housing by rotating the drive gear in a second direction to drive the drive cable section to retract the radiation source through the front cable section and the drive cable section. Claim 17 A method according to claim 14, further comprising attaching the front cable section to the drive cable section through a cable connector. Claim 18 A method according to claim 14, further comprising attaching the above-mentioned front cable section to the radiation source. Claim 19 delete Claim 20 delete

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