Patent Description:
Industrial radiography is often used for producing images of objects that are otherwise difficult to inspect, and involves exposing a source of high-energy radiation (e.g., gamma rays) and collecting penetrating and/or reflected rays to form a radiographic image. When not in use, gamma ray sources, such as radioactive isotopes, are stored in shielding devices.

<CIT> discloses a safety lock for securing a radiation source in a radiography exposure device.

<CIT> discloses a radiography camera system for manipulating a source through a source tube.

Methods and apparatus for control of radiographic source exposure are disclosed, substantially as illustrated by and described in connection with at least one of the figures, as set forth more completely in the claims.

For the purpose of promoting an understanding of the principles of the claimed technology and presenting its currently understood, best mode of operation, reference will be now made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the claimed technology is thereby intended, with such alterations and further modifications in the illustrated device and such further applications of the principles of the claimed technology as illustrated therein being contemplated as would typically occur to one skilled in the art to which the claimed technology relates.

Disclosed example remote controls for radiographic sources include: a forward cable section configured to extend into and through a radiographic source housing, to expose a radiographic source to an exterior of the housing, and to retract into and through the radiographic source housing to retract the radiographic source into the radiographic housing; a drive cable section coupled to the forward cable section; and a drive gear configured to extend the forward cable section by driving the drive cable section in a first direction, and to retract the forward cable section by driving the drive cable section in a second direction, wherein the forward cable section has a smooth exterior surface to have a lower friction than the drive cable section while traversing the radiographic source housing.

The remote controls further include a cable connector configured to mechanically couple the forward cable section to the drive cable section. In some example remote controls, the forward cable section and the drive cable section have respective lengths such that the cable connector and the forward cable section do not come into contact with the drive gear. In some example remote controls, the forward cable section and the drive cable section have respective lengths such that the cable connector does not enter the radiographic source housing. Some example remote controls further include a drive gear housing configured to contain the drive gear, the drive gear housing having a window configured to enable viewing of the cable connector when the forward cable section is at a predetermined position within the drive gear housing. In some example remote controls, the cable connector is configured to be detachable from at least one of the forward cable section or the drive cable section.

In some example remote controls, the forward cable section and the drive cable section have respective lengths such that the drive cable section does not enter the radiographic source housing. In some example remote controls, the forward cable section includes at least one of a semi-rigid spring steel, a spiral wound cable, a close-wound cable, or a compacted wire rope. In some example remote controls the forward cable section includes an outer coating configured to have less than a threshold coefficient of friction. In some example remote controls, the outer coating comprises at least one of Polytetrafluoroethylene (PTFE), molybdenum disulfide (MoS2) lubricants, graphite, Xylan®-brand fluoropolymer-based coatings, EthyleneChloroTrfluoroEthylene (ECTFE), Canadize-brand lubricants, or parylene.

Some example remote controls further include a handle configured to actuate the drive gear. Some example remote controls further include a motor configured to actuate the drive gear. Some example remote controls further include: a control conduit configured to cover portions of the forward cable section and the drive cable section located between the drive gear and the radiographic source housing; and a source connector configured to secure the control conduit to the radiographic source housing. In some example remote controls the forward cable section is configured to traverse an S-shaped source tube within the radiographic source housing to push the radiographic source through the S-shaped source tube to an outlet of the S-shaped tube.

Disclosed example methods to control exposure of a radiographic source involve: mechanically coupling a forward cable section to a radiographic source within a radiographic source housing; and extending the radiographic source to an exterior of the radiographic source housing from an interior of the housing to expose the radiographic source, by driving the forward cable section using a drive cable section, wherein the forward cable section has a smooth exterior surface to have a lower friction than the drive cable section while traversing the radiographic source housing.

In some example methods, the extending the radiographic source involves turning a drive gear in a first direction to drive the drive cable section to thereby drive the forward cable section. Some example methods further involve retracting the radiographic source into the radiographic source housing by turning the drive gear in a second direction to drive the drive cable section to thereby retract the radiographic source via the forward cable section and the drive cable section. The methods further involve attaching the forward cable section to the drive cable section via a cable connector. Some example methods further involve attaching the forward cable section to the radiographic source. In some example methods, the extending of the radiographic source ends prior to the drive cable section entering the radiographic source housing.

<FIG> illustrate example radiographic system <NUM> for providing radiation for radiography. The radiographic system <NUM> of <FIG> includes a radiographic source <NUM> which is contained within a radiographic source housing <NUM>. The example radiographic source <NUM> is a mass of radioactive material which emits radiation (e.g., X-rays and/or gamma rays) due to decay of the material.

The radiographic source housing <NUM> includes an S-shaped source tube <NUM> within a shield <NUM>. The source tube <NUM> provides a pathway for the radiographic source <NUM> to be exposed to an exterior of the shield <NUM> and retracted to a shielded position within the interior of the shield <NUM>. <FIG> illustrates the radiographic source <NUM> in the shielded position, and <FIG> illustrates the radiographic source in an exposed position.

To control the position of the radiographic source <NUM>, the radiographic source housing <NUM> enables connection of a control cable <NUM> to the radiographic source <NUM> for exposure and retraction of the radiographic source <NUM>. The control cable <NUM> may be physically attached or connected to a pigtail connector <NUM> that is physically coupled to the radiographic source <NUM>.

When engaged, the control cable <NUM> is controlled to extend into and through the source tube <NUM> to push the radiographic source <NUM> to an exposed position external to the radiographic source housing <NUM>. Conversely, the control cable <NUM> is retracted to pull the radiographic source <NUM> from the exposed position back into the source tube <NUM> to the shielded position, at which time the control cable <NUM> may be detached from the radiographic source <NUM>.

In the system <NUM> of <FIG>, the exposed position of the radiographic source <NUM> may be controlled by a guide tube <NUM>, through which the radiographic source <NUM> travels as the source <NUM> is pushed by the control cable <NUM>. The control cable <NUM> has sufficient column strength to push the radiographic source <NUM> through the source tube <NUM> and through the guide tube <NUM>.

The control cable <NUM> is controlled by a remote control <NUM>. The remote control <NUM> physically engages the control cable <NUM> to advance or retract the control cable <NUM> relative to the remote control <NUM>.

<FIG> is a cross-section of a conventional radiographic source shield assembly <NUM> in which portions of the radiographic source shield assembly <NUM> are subject to undesirable mechanical wear during use. As illustrated in <FIG>, the source tube <NUM> extends through the shield <NUM> in an S-shaped curve. As a result, there are multiple points <NUM> in the source tube <NUM> at which substantial friction occurs between the control cable <NUM> and the source tube <NUM> as a conventional control cable <NUM> advances and retracts through the source tube <NUM>.

Conventional control cables (also referred to as drive cables) are not purpose-built for source actuation in radiography applications. While radiography systems are designed to be sealed when assembled, radiography systems are effectively unsealed during setup, breakdown, and/or improper storage, which permits exposure to contaminants (e.g., dirt, sand, water) for which the radiography systems were not designed.

The conventional control cable <NUM> is a flexible steel cable with a helical outer winding. The helical outer winding enables the remote control <NUM> to engage the conventional control cable <NUM> and advance and retract the cable <NUM> with a high degree of precision. However, when not properly maintained, the helical outer windings can create substantial friction and/or abrasion at the points <NUM> on the interior of the source tube <NUM> as the conventional control cable <NUM> traverses the S-shaped curve. The friction and/or abrasion may create premature wear in the source tube <NUM> and reduce the useful life of the radiographic source shield assembly <NUM> and/or the radiographic source housing <NUM>. When the control cable <NUM> is not provided with sufficient cable lubrication, the friction and/or abrasion may also result in increased risk of failure of the control cable <NUM>.

<FIG> illustrate an example radiographic system <NUM> that may be used to implement the radiographic system <NUM> of <FIG>, in which a remote control device <NUM> used to control exposure of the radiographic source <NUM> subjects the radiographic source housing <NUM> to substantially less wear than in conventional systems (e.g., the conventional system of <FIG>).

In contrast with the conventional control cable <NUM> of <FIG>, the example remote control device <NUM> of <FIG> includes a forward cable section <NUM> configured to extend into and through the radiographic source housing <NUM>, and a drive cable section <NUM> coupled to the forward cable section <NUM>.

The drive cable section <NUM> may be similar or identical to the conventional control cable <NUM> of <FIG>. In contrast, the forward cable section <NUM> has a smooth exterior surface, such that the forward cable section <NUM> has a lower friction than the drive cable section <NUM> (or the conventional control cable <NUM>) while traversing the radiographic source housing <NUM> (e.g., through the source tube <NUM>). <FIG> is a cross-section of the example forward cable section <NUM> of <FIG>. For example, the forward cable section <NUM> may include an interior column <NUM> constructed using one or more of a semi-rigid spring material, a spiral wound cable, a close-wound cable, and/or a compacted wire rope. The interior column <NUM> may be a metal, a polymer, and/or any other material that has acceptable flexibility and is capable of linear actuation while maintaining sufficient strength in a radioactive environment for at least a threshold life span.

The interior column <NUM> may be wrapped, coated, or otherwise covered by an outer cover <NUM> (e.g., a coating, a physical cover, a wrap, etc.) that has less than a threshold coefficient of friction. In some examples, the outer coating is a tape, wrap, coating, and/or other covering, and may be constructed from Polytetrafluoroethylene (PTFE), molybdenum disulfide (MoS<NUM>) lubricants (sold by DuPont under the MolyKote® brand), graphite, Xylan®-brand fluoropolymer-based coatings (sold by Whitford Corporation), EthyleneChloroTrfluoroEthylene (ECTFE), Canadize-brand lubricants (sold by General Magnaplate), and/or parylene. However, any other appropriate material may be used as a coating. In some examples, a material may be chosen or modified to visibly show wear in the coating of the forward cable section <NUM>. As a result of the lower friction, the forward cable section <NUM> substantially reduces or eliminates abrasion and/or wear on the source tube <NUM> while advancing and retracting the radiographic source <NUM>.

The drive cable section <NUM> engages a drive gear <NUM> of the remote control device <NUM>. The drive gear <NUM> extends the forward cable section <NUM> (and the radiographic source <NUM>) by driving the drive cable section <NUM> in a first direction, and retracts the forward cable section <NUM> (and the radiographic source <NUM>) by driving the drive cable section in a second direction, while the forward cable section <NUM> does not come into contact with the drive gear <NUM>.

A cable connector <NUM> mechanically couples the forward cable section <NUM> to the drive cable section <NUM>. In the example of <FIG>, only the drive cable section <NUM> engages with the drive gear <NUM>. The forward cable section <NUM> and the drive cable section <NUM> have respective lengths such that the cable connector <NUM> and the forward cable section <NUM> do not come into contact with the drive gear <NUM>. Similarly, the forward cable section <NUM> and the drive cable section <NUM> have respective lengths such that the cable connector <NUM> and the drive cable section <NUM> do not enter the radiographic source housing <NUM> and/or do not enter the source tube <NUM>.

The example remote control device <NUM> includes a control conduit <NUM> to cover the forward cable section <NUM> and/or the drive cable section <NUM> at least between the drive gear <NUM> and the radiographic source housing <NUM>. In the example of <FIG>, the control conduit <NUM> is coupled to a conduit connector <NUM> that secures the control conduit <NUM> to the radiographic source housing <NUM> and aligns an outlet of the control conduit <NUM> with a corresponding inlet of the radiographic source housing <NUM>. For example, the forward cable section <NUM> and a forward connector <NUM> may be connected to the radiographic source <NUM> via a pigtail connector <NUM> and a pigtail cable <NUM>. Once connected, the conduit connector <NUM> can be connected to the radiographic source housing <NUM> and secured, the forward cable section <NUM> may be physically attached to the pigtail cable <NUM> affixed to the radiographic source <NUM>. In some examples, the pigtail cable <NUM> is made of the same or similar construction as the forward cable section <NUM> or the same or similar construction as the drive cable section <NUM>.

The example conduit connector <NUM> may be implemented using conventional connectors used with the Sentinel <NUM> Gamma Ray Source Projection system, sold by QSA Global, Inc. , of Burlington, MA.

The disclosed example remote control, including the forward cable section <NUM>, has the advantage that the forward cable section <NUM> reduces overall sliding friction with the source tube <NUM>, relative to the conventional control cable <NUM>. The reduction in sliding friction extends the useful life of the source tube <NUM> by extending the time and usage required to wear through the tube and into the shield <NUM>, which may be depleted uranium, adjacent to the source tube <NUM>. This increase in useful life of the source tube <NUM> is a substantial financial benefit for the owners of the system.

<FIG> illustrates an example manual remote control <NUM> configured to implement the radiographic system <NUM> of <FIG>. The manual remote control <NUM> includes a pistol-style housing <NUM> that houses the drive gear <NUM>. The housing <NUM> includes a grip <NUM>, which may be grasped by an operator of the remote control <NUM> when turning a handle <NUM> attached to the drive gear <NUM>. Turning the handle <NUM> in an exposure (e.g., advancement) direction causes the drive gear <NUM> to advance the drive cable section <NUM> toward the conduit connector <NUM>, which causes the forward cable section <NUM> to similarly advance and push the radiographic source <NUM>. Conversely, turning the handle <NUM> in a retraction direction (opposite the exposure direction) causes the drive gear <NUM> to retract the drive cable section <NUM> away from the conduit connector <NUM>, which pulls the forward cable section <NUM> to retract the radiographic source <NUM> toward the shielded or storage position within the source tube <NUM>.

<FIG> is a more detailed view of the example manual remote control <NUM> of <FIG>, including a window <NUM> through which the condition of the cable connector of <FIG> may be observed without exposure of the cable connector to the exterior of the manual remote control.

While <FIG> illustrate a pistol-style housing, reel-style housings and/or any other type of housing may be used. Additionally or alternatively, the drive gear <NUM> may be replaced with a different type of actuator and/or drive interface to drive the drive cable section <NUM> and/or the forward cable section <NUM>. In some examples, the drive gear <NUM> (or other drive interface) may be automatically actuated (e.g., via a motor) instead of manually actuated via a handle.

<FIG> is a flowchart representative of an example method <NUM> which may be performed to control exposure of a radiographic source <NUM> using the system of <FIG>. While the method <NUM> is disclosed below with reference to certain applicable elements, local regulations may require that additional actions or steps, such as (but not limited to) confirmatory surveys of radiation levels prior to and/or after exposure of the radioactive source, be taken in conjunction with the disclosed steps.

At block <NUM>, the forward cable section <NUM> is mechanically coupled to a radiographic source <NUM> via a conduit connection. For example, the forward cable section <NUM> may be mechanically attached to the pigtail connector <NUM> via the forward connector <NUM>, and/or the control conduit <NUM> may be coupled to the radiographic source housing <NUM>.

At block <NUM>, the drive gear <NUM> is turned in an advancement direction to advance the drive cable section <NUM>. As a result of advancing the drive cable section <NUM>, the forward cable section <NUM> and the radiographic source <NUM> are returned to the stored position within the shield <NUM>.

At block <NUM>, the radiographic source <NUM> is exposed for a threshold time period to capture one or more radiographic image(s) (e.g., via a radiation detector or imager).

At block <NUM>, the drive gear <NUM> is turned in a retraction direction to retract the drive cable section <NUM>. As a result of retracting the drive cable section <NUM>, the forward cable section <NUM> and the radiographic source <NUM> are retracted to secure the radiographic source <NUM>.

At block <NUM>, it is determined whether the radiographic source <NUM> is secured in the shielded position. If the radiographic source <NUM> has not been secured in the shielded position (block <NUM>), the method <NUM> returns to block <NUM> to continue retraction.

When the radiographic source <NUM> is positioned in the shielded position (block <NUM>), at block <NUM> the forward cable section <NUM> may be detached from the radiographic source <NUM>. The example method <NUM> then ends.

Claim 1:
A remote control (<NUM>) for a radiographic source (<NUM>), the remote control (<NUM>) comprising:
a forward cable section (<NUM>) configured to:
extend into and through a radiographic source housing (<NUM>), to expose a radiographic source (<NUM>) to an exterior of the housing (<NUM>), and to retract into and through the radiographic source housing (<NUM>) to retract the radiographic source (<NUM>) into the radiographic housing (<NUM>);
a drive cable section (<NUM>) coupled to the forward cable section (<NUM>);
a cable connector (<NUM>) configured to mechanically couple the forward cable section (<NUM>) to the drive cable section (<NUM>); and
a drive gear (<NUM>) configured to extend the forward cable section (<NUM>) by driving the drive cable section (<NUM>) in a first direction, and to retract the forward cable section (<NUM>) by driving the drive cable section (<NUM>) in a second direction, wherein the forward cable section (<NUM>) has a smooth exterior surface to have a lower friction than the drive cable section (<NUM>) while traversing the radiographic source housing (<NUM>).