Patent Publication Number: US-2021183492-A1

Title: Brachytherapy Applicator Formation Method and Apparatus

Description:
TECHNICAL FIELD 
     These teachings relate generally to brachytherapy and more particularly to the formation and use of brachytherapy applicators. 
     BACKGROUND 
     The use of radiation to treat medical conditions comprises a known area of prior art endeavor. For example, radiation therapy comprises an important component of many treatment plans for reducing or eliminating unwanted tumors. Unfortunately, applied radiation does not inherently discriminate between unwanted materials and adjacent tissues, organs, or the like that are desired or even critical to continued survival of the patient. As a result, radiation is ordinarily applied in a carefully administered manner to at least attempt to restrict the radiation to a given target volume. A so-called treatment plan often serves in the foregoing regards. 
     Brachytherapy is a form of radiotherapy where one or more sealed radiation sources are physically placed inside or at least near to a patient&#39;s target treatment volume. The radiation source is often moved along one or more channels that comprise a part of a brachytherapy applicator to specific locations where the radiation source is allowed to momentarily dwell for a predetermined amount of time. Brachytherapy treatment plans often specify particular locations along particular channels where the radiation source is manually or automatically momentarily positioned for the predetermined dwell time. 
     While often a very effective therapy, brachytherapy applicators often represent a number of trade-offs. For example, one or more of the channels may not be ideally located (in whole or in part) to effectively achieve the desired irradiation of the patient&#39;s target volume while sparing as much as possible other volumes such as organs at risk. 
     In some cases a brachytherapy applicator is custom made to better suit the specifics of a given patient&#39;s situation. Unfortunately, this often requires a skilled person and generally represents a very time-consuming process that may not, in the end, represent a desired result. In addition, the applicant has determined that prior art approaches to radiation treatment plan optimization using a custom-made brachytherapy applicator only poorly leverage the available potential opportunities. For example, once an applicator is created, it can consume several hours to generate a corresponding radiation treatment plan since all the channels must be digitized and the dose distribution needs adapted around the applicator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above needs are at least partially met through provision of the brachytherapy applicator formation method and apparatus described in the following detailed description, particularly when studied in conjunction with the drawings, wherein: 
         FIG. 1  comprises a block diagram as configured in accordance with various embodiments of these teachings; 
         FIG. 2  comprises a flow diagram as configured in accordance with various embodiments of these teachings; 
         FIG. 3  comprises a perspective view as configured in accordance with various embodiments of these teachings; 
         FIG. 4  comprises a top plan view as configured in accordance with various embodiments of these teachings; 
         FIG. 5  comprises a top plan view as configured in accordance with various embodiments of these teachings; and 
         FIG. 6  comprises a top plan view as configured in accordance with various embodiments of these teachings. 
     
    
    
     Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present teachings. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present teachings. Certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein. The word “or” when used herein shall be interpreted as having a disjunctive construction rather than a conjunctive construction unless otherwise specifically indicated. 
     DETAILED DESCRIPTION 
     Generally speaking, these various embodiments serve to facilitate forming a brachytherapy applicator to use when administering therapeutic radiation to a particular patient&#39;s targeted area. This includes accessing image information for the particular patient that includes the targeted area and at least some adjacent non-targeted area or areas. A control circuit uses that image information along with prescribed dosing information for the particular patient to automatically generate a brachytherapy applicator design specifically to treat the particular patient&#39;s targeted area via brachytherapy. A corresponding brachytherapy applicator is then manufactured as a function, at least in part, of the brachytherapy applicator design to provide a manufactured brachytherapy applicator. 
     These teachings are highly flexible in practice and practical as well. By one approach, for example, the aforementioned targeted area can include an area of skin for the particular patient. As another example, these teachings will accommodate using any of a variety of different kinds of imaging information including but not limited to three-dimensional images obtained using any of computed tomography, magnetic resonance, optically-scanned image information, or other methodologies known in the art. 
     By one approach, the automatic generation of the brachytherapy applicator design includes automatically setting at least one channel parameter. Examples in these regards include but are not limited to a distance that separates at least two channels (including but not limited to channel pitch), an angle between two channels, a degree of curvature for a channel, and an extent to which at least two channels are non-parallel to one another. In any or all of these cases the control circuit can be configured to select the particular parameter from only amongst a permitted range of available candidate values. 
     By one approach the aforementioned manufacturing of the brachytherapy applicator includes use of an additive manufacturing platform such as a three-dimensional printer. 
     By one approach the control circuit can access image information for the manufactured brachytherapy applicator and then use that image information to optimize a radiation treatment plan that includes optimized radioactive source locations (using the channels of the brachytherapy applicator) and dwell times to thereby provide an optimized radiation treatment plan. The latter can then be used to administer therapeutic radiation to the particular patient&#39;s targeted area. 
     So configured, a brachytherapy applicator custom designed for a particular patient can be readily and relatively quickly specified and manufactured. At least some of the specifics of the brachytherapy applicator can be selected to improve the likely efficacy of the plan when used to administer therapeutic radiation to the particular patient&#39;s targeted area. 
     These and other benefits may become clearer upon making a thorough review and study of the following detailed description. Referring now to the drawings, and in particular to  FIG. 1 , an illustrative apparatus  100  that is compatible with many of these teachings will be presented. 
     In this particular example, the enabling apparatus  100  includes a control circuit  101 . Being a “circuit,” the control circuit  101  therefore comprises structure that includes at least one (and typically many) electrically-conductive paths (such as paths comprised of a conductive metal such as copper or silver) that convey electricity in an ordered manner, which path(s) will also typically include corresponding electrical components (both passive (such as resistors and capacitors) and active (such as any of a variety of semiconductor-based devices) as appropriate) to permit the circuit to effect the control aspect of these teachings. 
     Such a control circuit  101  can comprise a fixed-purpose hard-wired hardware platform (including but not limited to an application-specific integrated circuit (ASIC) (which is an integrated circuit that is customized by design for a particular use, rather than intended for general-purpose use), a field-programmable gate array (FPGA), and the like) or can comprise a partially or wholly-programmable hardware platform (including but not limited to microcontrollers, microprocessors, and the like). These architectural options for such structures are well known and understood in the art and require no further description here. This control circuit  101  is configured (for example, by using corresponding programming as will be well understood by those skilled in the art) to carry out one or more of the steps, actions, and/or functions described herein. 
     This illustrative example the control circuit  101  operably couples to a memory  102 . This memory  102  may be integral to the control circuit  101  or can be physically discrete (in whole or in part) from the control circuit  101  as desired. This memory  102  can also be local with respect to the control circuit  101  (where, for example, both share a common circuit board, chassis, power supply, and/or housing) or can be partially or wholly remote with respect to the control circuit  101  (where, for example, the memory  102  is physically located in another facility, metropolitan area, or even country as compared to the control circuit  101 ). 
     In addition to image information and parameter ranges as described herein, this memory  102  can serve, for example, to non-transitorily store the computer instructions that, when executed by the control circuit  101 , cause the control circuit  101  to behave as described herein. (As used herein, this reference to “non-transitorily” will be understood to refer to a non-ephemeral state for the stored contents (and hence excludes when the stored contents merely constitute signals or waves) rather than volatility of the storage media itself and hence includes both non-volatile memory (such as read-only memory (ROM) as well as volatile memory (such as a dynamic random access memory (DRAM).) 
     By another optional approach the control circuit  201  also operably couples to a user interface  103 . This user interface  103  can comprise any of a variety of user-input mechanisms (such as, but not limited to, keyboards and keypads, cursor-control devices, touch-sensitive displays, speech-recognition interfaces, gesture-recognition interfaces, and so forth) and/or user-output mechanisms (such as, but not limited to, visual displays, audio transducers, printers, and so forth) to facilitate receiving information and/or instructions from a user and/or providing information to a user. 
     By yet another optional approach (in lieu of the foregoing or in combination therewith) the control circuit  201  operably couples to an additive manufacturing platform  104  such as a so-called 3-D printer. By this operable coupling, and as desired, the control circuit  101  may provide printing files and/or otherwise control the operation of the additive manufacturing platform  104  or may simply provide the design information described herein for a brachytherapy applicator to the additive manufacturing platform  104 . 
     So configured, the additive manufacturing platform  104  can manufacture a brachytherapy applicator  105  per the design of the control circuit  101  as described herein. (Additive manufacturing platforms in general, and 3-D printers in particular, comprise a well-understood area of prior art endeavor. Accordingly, further discussion in those regards is not presented here for the sake of brevity.) 
     By yet another optional approach (and again in lieu of the foregoing or in combination therewith, the control circuit  201  operably couples to a radiation treatment platform  106 . The radiation treatment platform  106  is configured to deliver therapeutic radiation to a corresponding patient  107  by way of brachytherapy. In application settings where one or more of the radioactive sources are to be automatically placed/moved, the radiation treatment platform  106  can include a so-called afterloader that functions to move a radioactive source along a corresponding channel to a particular location for a particular dwell time. Depending upon the specifics of the radiation treatment plan, a given radiation source may dwell at a number of locations along any given channel. 
     With continued reference to  FIG. 1 , and referring now as well to  FIG. 2 , a process  200  to manufacture a brachytherapy applicator  105  will be described. 
     At block  201 , the control circuit  101  accesses image information for a particular patient  107 . By one approach the control circuit  101  accesses the above-described memory  102  to obtain some or all of this image information. The image information includes the targeted area to receive radiation (such as a tumor) and at least some adjacent non-targeted area (such as any of a variety of tissues, organs, and so forth that are closely to the side of, in front of, or behind the targeted area). 
     These teachings will accommodate a variety of different types of image information. By one approach the image information comprises three-dimensional images. Examples include but are not limited to computed tomography (CT) images, magnetic resonance (MR) information, and optically-scanned image information. The utilized information may all be of a same kind of information (such as all comprising CT images) or may be a mix of different kinds of image information as desired. 
     At block  202 , this process  200  provides for using the control circuit  101  to use the accessed image information along with prescribed dosing information for the particular patient  107  to automatically generate a brachytherapy applicator design specifically to treat the particular patient&#39;s targeted area via brachytherapy. The prescribed dosing information may specify, for example, a desired minimum level of radiation dosing (expressed, for example, using Gray units) for the targeted area along with a desired maximum level of radiation dosing for at least some part of the aforementioned non-targeted area. 
     In this illustrative example the brachytherapy applicator design will presume use of the aforementioned additive manufacturing platform  104 , and in particular will presume the use of a 3-D printer. In a typical application setting the brachytherapy applicator  105  will be formed using an appropriate plastic material (and possibly a radio-transparent plastic material). These teachings will also accommodate, however, using essentially any other material of choice. With momentary reference to  FIG. 3 , the design of the brachytherapy applicator  105  may intentionally conform to some corresponding patient surface. For example, when the resultant brachytherapy applicator  105  is designed to be disposed adjacent to a particular external surface of the patient  107 , the brachytherapy applicator  105  can have a main body  301  that is shaped to conform to that body portion. 
     In the alternative, the body  301  of the brachytherapy applicator  105  can be comprised of a slightly flexible material. So configured, the brachytherapy applicator  105  can be manipulated as necessary when fitted to the patient to conform to the relevant part of the patient&#39;s body. (In a typical application setting the brachytherapy applicator  105  will be held in its deployed position on the patient&#39;s body using an appropriate adhesive and/or adhesive tape or the like). 
     The design of the brachytherapy applicator  105  will also be sized to ensure appropriate coverage of the targeted area. The size and or shape of the brachytherapy applicator  105  may also be selected to help ensure that the brachytherapy applicator  105  can be appropriately and securely affixed to the patient  107 . 
     The design of the brachytherapy applicator  105  will also include one or more channels  302  to receive a brachytherapy radiation source. Accordingly, the channel will have a typically cylindrical form factor to readily receive such a source or applicator channel such as a closed ended catheter. Presuming use of a 3-D printer, these channels  302  will be comprised of a same material as the main body  301  and will typically be formed integral to the latter as well. 
     Pursuant to these teachings, the aforementioned design of the brachytherapy applicator  105  can provide for a customized selection of a number of channels. In addition, the design can provide for a customized set of parameters regarding those channels. With momentary reference to  FIG. 4 , by one approach such a parameter can specify the distance D between two such channels  302 . If desired, the channels  302  can all be equally spaced from one another and hence the selectable parameter can comprise channel pitch. By another approach, in lieu of the foregoing or in combination therewith, and referring momentarily to  FIG. 5 , such a channel parameter can comprise an angle A between two such channels  302 . By yet another approach, again in lieu of the foregoing or in combination therewith, and referring momentarily to  FIG. 6 , such a channel parameter can comprise a degree of curvature of a channel  302 . 
     By one approach, the control circuit  101  is configured to automatically generate the brachytherapy applicator design by automatically setting one or more channel parameters after optimizing the brachytherapy applicator design with respect to at least one objective that corresponds to the prescribed dosing information. The latter activity can include automatically trying, in an incremental manner, a series of different values for each selected channel parameter. (Those skilled in the art will understand that optimization objectives provide a measure by which a process can test or assure that a particular specified dose is being uniformly administered through the patient&#39;s targeted area while avoiding undue dosing of other patient areas.) 
     If desired, such channel parameters may be selectable at any particular resolution or granularity and without limits. More typically, it may be beneficial to constrain each such parameter to a range of available candidate parameter values  203  from which the control circuit can select. These ranges can be based upon the physical limitations that characterize a specific radiation treatment platform. For example, when selecting a particular distance that separates two adjacent channels  302 , the control circuit  101  may be unable to select a distance that exceeds a particular range of values and/or that is less than such a range. As another example, when selecting a particular angle between two adjacent channels  302 , the control circuit  101  may be unable to select an angle that exceeds a particular range of values and/or that is less than such a range. And as yet another example, when selecting a particular degree of curvature for a given channel  302 , the control circuit  101  may be unable to select a degree of curvature that exceeds a particular range of values and/or that is less than such a range. 
     If desired, the design of the brachytherapy applicator  105  can be informed by other parameters that are either automatically selected and/or user selected (or modified). Examples include target region information, treatment depth, applicator thickness, entry angle, and so forth. 
     Also if desired, these teachings will accommodate providing the user with an opportunity (for example, via the aforementioned user interface  103 ) to modify the automatically generated brachytherapy applicator design (for example, by modifying channels or other structures). 
     So configured, the control circuit  101  can design a brachytherapy applicator  105  that is well-suited, in terms of its size and shape, to be disposed upon a particular part of the patient&#39;s body (or potentially disposed within the patient&#39;s body) and which has channels suitably and particularly located to help ensure beneficial placement of radiation sources when administering radiation therapy to the particular patient  107 . 
     At block  204 , this process  200  provides for manufacturing a brachytherapy applicator (using, for example, the above-mentioned additive manufacturing platform  104 ) as a function, at least in part, of the brachytherapy applicator design to thereby provide a resultant manufactured brachytherapy applicator  105 . By one approach, the control circuit  101  facilitates this activity by generating printing files based upon the brachytherapy applicator design. 
     Although the radiation treatment plan has already been optimized, by one optional approach and with the specifics of the brachytherapy applicator&#39;s physical layout and dimensions now being precisely known and as shown at optional block  205 , this process  200  can provide for again optimizing the radiation treatment plan for the particular patient  107  that makes use of accessed image information  206  for the manufactured brachytherapy applicator  105 . In particular, using that image-based information regarding the precise locations of the channels and the intended disposition of the applicator  105  on (or in) the patient, the control circuit  101  can optimize a radiation treatment plan that includes optimized radioactive source locations and dwell times to thereby provide an optimized radiation treatment plan. 
     It will be understood that the expression “optimizing” should not be confused with the idea of identifying an objectively “optimum” plan that is superior to all other possible plans. Instead, such optimization comprises iteratively assessing alternatives (such as the use of alternative physical parameters for various aspects of the proposed treatment) to a given plan to typically identify a series of successively-better plans. As used herein, “optimization” will be understood to refer to improving a candidate treatment plan without necessarily ensuring that the optimized result is, in fact, the singular best solution. 
     At optional block  207 , if desired the manufactured brachytherapy applicator  105  and the optimized radiation treatment plan can be used to administer therapeutic radiation via brachytherapy to the particular patient&#39;s targeted area. The use of a treatment plan and a brachytherapy applicator to administer therapeutic radiation constitutes a well understood area of prior art endeavor that requires no further elaboration here. 
     These teachings facilitate manufacturing and using a brachytherapy applicator via an approach that does not require a highly skilled technician and hence constitutes a significant improvement over prior art approaches in those regards. 
     Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept.