Patent Application
20120178983
This disclosure generally relates to the field of brachytherapy and, more particularly to orienting a brachytherapy treatment catheter within a treatment cavity, such as a breast lumpectomy cavity.
Malignant tumors are often treated by surgical resection to remove as much of the tumor as possible. Infiltration of the tumor cells into normal tissue surrounding the tumor, however, can limit the therapeutic value of surgical resection because the infiltration can be difficult or impossible to treat surgically. Radiation therapy can be used to supplement surgical resection by targeting the residual tumor margin after resection, with the goal of reducing its size or stabilizing it. Radiation therapy can be administered through one of several methods, or a combination of methods, including external-beam radiation, stereotactic radiosurgery, and brachytherapy. The term “brachytherapy,” as used herein, refers to radiation therapy delivered by a source of therapeutic rays inserted into the body at or near a tumor or other proliferative tissue disease site.
A typical breast brachytherapy radiation treatment involves insertion of an applicator by a surgeon. A brachytherapy applicator may typically include a flexible catheter shaft with an inflatable balloon mounted on its distal end. One or more dosing lumens extend within the catheter shaft and into the balloon. The catheter shaft is inserted into a body so that the balloon is positioned within a resected cavity. The balloon is subsequently inflated and radioactive material, for example in the form of one or more radioactive seeds, is loaded into one or more of the dosing lumens for radiation delivery. The brachytherapy catheter system is removed upon completion of treatment. In single lumen brachytherapy treatment devices the dosing lumen is positioned along a central axis of the balloon such that substantially symmetrical isodose profiles may be achieved during treatment, i.e., a radiation dose of equal intensity is delivered to the tissue surrounding the balloon. In multi-lumen brachytherapy treatment devices one or more lumens are offset from the central axis within the balloon such that asymmetrical isodose profiles may be achieved during treatment, i.e., a radiation dose of greater intensity is delivered to certain areas of tissue surrounding the balloon in comparison to other areas, which receive a dose of lesser intensity. Proper orientation of the treatment device is desirable for delivering an asymmetric isodose profile. A physician may be able to make minor adjustments by applying direct rotational force to the shaft by hand. However, the catheter shaft may be ill-suited to transmitting torque. For example, a flexible shaft may initially twist in response to rotational force and then unpredictably untwist as applied resistance to twist increases and torque exceeds friction between the applicator and tissue. As a result, it is difficult to precisely orient the applicator.
In accordance with an aspect of the invention a device for orienting a brachytherapy applicator implanted in a treatment cavity includes an elongated body defining an open proximal end, an open distal end, and an open channel between the proximal and distal ends. The channel slidably receives at least a portion of a brachytherapy applicator during use. The device may include a manually engageable gripping element. The gripping element may be located at the proximal end of the elongated body, and be operable to constrict at least a portion of the channel to prevent rotational movement between the elongated body and a portion of a brachytherapy applicator inserted into the channel. The device may also include at least one engaging element disposed on a portion of the elongated body for releasably engaging at least one corresponding engaging element on the brachytherapy applicator, wherein the elongated body and brachytherapy applicator are prevented from rotating relative to each other when the at least one engaging element of the elongated body engages the at least one corresponding engaging element of the brachytherapy applicator.
In accordance with another aspect of the invention a brachytherapy system includes a brachytherapy applicator for insertion into a treatment cavity and a device for orienting the brachytherapy applicator upon insertion into a treatment cavity. The brachytherapy applicator includes a flexible shaft defining a proximal end, a distal end and a shaft lumen extending between the proximal end distal ends, an inflatable member disposed about the distal end of the shaft, at least one dosing lumen extending through the shaft lumen and into the inflatable member, and at least one first engaging element disposed on a portion of the shaft. The device for orienting the brachytherapy applicator includes an elongated body defining an open proximal end, an open distal end, and an open channel between the proximal and distal ends adapted for slidably receiving at least a portion of the flexible shaft. The device may also include a manually engageable gripping element at the proximal end of the elongated body, the gripping element operable to constrict at least a portion of the channel around at least a portion of the flexible shaft to prevent rotational movement between the elongated body and the brachytherapy applicator. Furthermore, the device may include at least one second engaging element adapted for releasably engaging the at least one first engaging element of the brachytherapy applicator. The device and brachytherapy applicator are prevented from rotating relative to each other when the at least one first engaging element of the elongated body engages the at least one second engaging element of the brachytherapy applicator.
In accordance with another aspect of the invention a method for orienting a brachytherapy applicator with the device described above includes the steps of positioning the elongated body on the shaft and controlling axial or rotational movement of the applicator via the device. This may be accomplished by positioning the device relative to the applicator such that the first and second engaging elements engage one another, thereby preventing rotational movement of the shaft and elongated body relative to each other. Applying a force to the gripping element and constricting at least a portion of the channel around at least a portion of the shaft prevents rotational movement of the shaft and elongated body relative to each other. An operator may then perform one or more of (i) axially moving the orienting device and simultaneously axially moving the brachytherapy device relative to a target tissue area of the treatment cavity and (ii) rotating the orienting device and simultaneously rotating the brachytherapy device relative to a target tissue area of the treatment cavity.
The invention provides a cost effective and easily operable way to orient a brachytherapy applicator. The device enables 1:1 rotation with reduced shaft twist and helps avoid stick-slip by securing a segment of the applicator shaft against twist and spreading the torque load. Tabs reduce reliance on friction between fingers and device or shaft. Advantageously, the device can be mounted and removed without removing the applicator from the treatment cavity. It is also advantageous that the orienting device is an “external tool” that engages the flexible shaft of the brachytherapy applicator externally about its outer surface as opposed to an “internal tool” which must be inserted down an internal shaft lumen to engage an internal engagement structure. Such an external configuration reduces or eliminates the need to incorporate more costly and complex internal structures within the tight diametrical confines of the applicator, which are required to accommodate an internal orienting device.
These and other features, aspects, and advantages of the disclosed embodiments will become better understood with regard to the following description, appended claims, and accompanying drawings.
Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. The exemplification set out herein illustrates certain embodiments of the invention, in one, or more forms, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Referring to
The applicator 20 further includes a flexible inflation lumen 38, which channels fluid into and out of the inflatable member 34 to inflate and deflate the inflatable member as required. When inflated, inflatable member 34 helps to maintain the position of the applicator 20 with respect to a treatment cavity (see e.g.
The applicator 20 further includes at least one engaging member 42 (see e.g.
Referring now to
The device 50 includes one or more features which enable a physician to control movement of the brachytherapy applicator. For example, the device may be used to control axial, rotational, or both axial and rotational movement of the applicator 20. The features may include a mechanism which secures the device 50 to the applicator 20 such that the applicator moves in response to movement of the device 50. Independent control may be provided such that axial control is disabled while the applicator is rotationally positioned. Operation of the mechanism may be reversible such that the device 50 may be disengaged from the applicator 20, e.g., after the applicator has been properly positioned. The device may also be used multiple times to reposition the applicator by repeatedly engaging and disengaging the device and applicator.
In the illustrated embodiment the channel 58 is capable of gripping or otherwise frictionally engaging an inserted shaft or catheter body, such as the shaft 22 of the above-described brachytherapy applicator 20. In such instances the channel 58 defines a relaxed state and a constricted state. When in the relaxed state, the inner surface 52 of the channel does not frictionally engage the inserted shaft 22 so that the elongated body 52 may slide axially in at least one direction relative to the shaft 22. When in the constricted state, at least a portion of an inner surface 62 of the channel frictionally engages at least a portion of an outer surface of an inserted shaft 22 so that the elongated body 52 is not axially or rotationally slidable relative to the shaft 22.
A manually engageable gripping element 64 provides an actuator operable to transition or otherwise move the channel between the relaxed and constricted states. The manually engageable gripping element 64 resides at or about the proximal end 54 of the elongated body 52. The gripping element 64 may form a portion or appendage of the elongated body (i.e. the gripping element 64 and elongated body 52 may be a single piece), or the gripping element 64 may be a separate component attached to the elongated member 52. As noted above, the gripping element 64 is operable to transition or otherwise move the channel between the relaxed and constricted states. In one embodiment, the gripping element 64 includes a pair of opposing tabs or surfaces 66, 68 adapted to move or otherwise flex or bend toward each upon application of a lateral force on each tab. The forces are directed inward in a squeezing type motion applied by the operator to substantially simultaneously transition the channel 58 from its relaxed state to its constricted state. Releasing the gripping element (i.e. ceasing the application of the lateral forces on the tabs) will return the channel 28 to its relaxed state; hence, the channel is biased in its relaxed state.
Referring now to
The orienting device 50 described above may be made from a polymer such as polypropylene, fluorinated ethylene propylene (FEP), nylon or polyethylene block amide (PEBA). However, as one skilled in the art would recognize, the device 50 may be made from a number of suitable materials including, but not limited to, additional polymers, metals and combinations thereof.
Having thus described the system 10 and its primary components, an example method of use will now be described. With the brachytherapy applicator 20 having been surgically implanted into a treatment cavity, such as a resected breast lumpectomy cavity 80 shown in
As shown in
As may be recognized by those of ordinary skill in the pertinent art based on the teachings herein, numerous changes and modifications may be made to the above-described and other embodiments of the present invention without departing from the spirit and scope of the invention as defined and/or described in the specification, drawings and appended claims. It should be understood that the embodiments shown and described and all changes, modifications and equivalents that come within the spirit and scope of the invention are desired to be protected. Accordingly, this disclosure is to be taken in an illustrative, as opposed to a limiting sense.
All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those skilled in the art unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary. Further, regarding the methods and processes described herein, it should be understood that although the steps of such methods and processes have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps (not described) could be added or implied, or that certain steps described herein could be omitted.
