Patent Application
20140270077
This invention relates generally to the therapeutic irradiation of a patient's target volume via a moving source of radiation.
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 healthy 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.
Many treatment plans provide for delivering radiation towards a target tissue from a plurality of different angles. Arc therapy, for example, comprises one such approach. Generally speaking, such an approach has the benefit of tending to provide a desired radiation dose to the target volume while lessening the overall radiation impact on any particular non-targeted material by spreading the collateral radiation dose over a larger body of non-targeted material.
That said, such approaches can still potentially result in delivering a particularly sensitive non-targeted area of the patient's body with an undue radiation dose (either as a single dose or as an aggregated dose that accumulates, for example, over a sequence of radiation treatments).
The above needs are at least partially met through provision of the method and apparatus pertaining to irradiating a treatment volume while maintaining the treatment volume a predetermined offset distance from the radiation-treatment isocenter described in the following detailed description, particularly when studied in conjunction with the drawings, wherein:
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 invention. 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 invention. 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.
Generally speaking, these various embodiments presume use of a (1) radiation-therapy machine having a movable radiation source and a corresponding radiation-treatment isocenter and (2) a patient-support platform. A control circuit is configured to control selective movement of at least the patient-support platform (during a radiation treatment session and typically while the radiation source is also moving) such that during at least a part of the radiation treatment session a patient's radiation-treatment target volume is maintained at a predetermined offset distance away from the radiation-treatment isocenter.
By one approach the control circuit maintains that predetermined offset distance for the duration of the radiation treatment session. The predetermined offset distance can vary with the application setting. Example offset distances of possible value, however, can range from, by way of example, around 2 centimeters to around 20 centimeters (with longer distances certainly being possible and with a distance of around 10 centimeters being useful for at least some application settings).
By one approach, the control circuit is further configured to control selective movement of at least the patient-support platform such that during the radiation treatment session the patient's radiation-treatment target volume moves along a predetermined trajectory with respect to the radiation-treatment isocenter (even while maintaining the aforementioned predetermined offset distance). It can be useful in at least some application settings to constrain that predetermined trajectory to a preselected geometric volume. These teachings are highly flexible in practice and will accommodate a variety of differently-shaped geometric volumes. For many application settings, and for ease of calculation, it can be useful to use a sphere as the predetermined geometric volume (where the sphere can have its center coincident with the aforementioned radiation-treatment isocenter and its radius equal to the aforementioned predetermined offset distance).
So configured, and contrary to typical practice in these regards, the treatment volume can be exposed to radiation via a plurality of planes instead of via only a single plane during a single radiation-treatment session. Accordingly, these teachings permit a given radiation treatment plan greater flexibility to avoid the undue irradiation of non-targeted areas including particularly critical or susceptible non-targeted areas.
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
This description presumes that the radiation source 102 outputs radiation as a so-called fan beam. One such fan beam is denoted by reference numeral 106 and another such fan beam (as output by the radiation source 102 when the latter is positioned in another location denoted by reference numeral 104) is denoted by reference numeral 107. (It will be understood that any of a variety of known beam-shaping tools (such as but not limited to adjustable jaws and multi-leaf collimators) can be used to adjust these fan beams narrower or wider than as drawn as appropriate to the needs of a given treatment plan.)
Generally speaking, this description presumes that the radiation-therapy machine 101 is of sufficient size to receive at least a portion of a patient during the administration of a radiation dose. There are numerous such radiation-therapy machines known in the art. Generally speaking, their construction and manner of use comprises a well-understood area of prior art endeavor. Accordingly, for the sake of brevity and simplicity further description in these regards will not be provided here except where additional details may be particularly relevant to a particular description provided further herein.
The radiation-therapy apparatus 100 further comprises a patient-support platform 108. Referring momentarily to
This patient-support platform 108 is sized and configured to fit at least partially within the aforementioned radiation-therapy machine 101. The patient-support platform 108 is also configured to selectively move relative to the radiation-therapy machine 101. The specific available directions of movement can vary to some extent with the application setting. Examples of potentially useful directions of relative movement include, but are not limited to, vertical movement as denoted by reference numeral 201, lateral horizontal movement as denoted by reference numeral 202, and longitudinal horizontal movement as denoted by reference numeral 203. Other examples include yaw movement (i.e., rotational movement about a vertical axis) as denoted by reference numeral 204 and pitch movement as denoted by reference numeral 205.
The present teachings are highly flexible in practice and will readily accommodate other kinds of movement by the patient-support platform 108 when available. For example, an ability of the patient-support platform 108 to roll with respect to the longitudinal axis could serve in these regards. These teachings will also readily accommodate the use of a patient-support platform 108 that comprises two or more separate patient-support components that can each move, at least to some extent, independently of one another.
Referring again to
By one optional approach the control circuit 109 also operably couples to a memory 110. The memory 110 may be integral to the control circuit 109 or can be physically discrete (in whole or in part) from the control circuit 109 as desired. This memory 110 can also be local with respect to the control circuit 109 (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 109 (where, for example, the memory 110 is physically located in another facility, metropolitan area, or even country as compared to the control circuit 109).
This memory 110 can serve, for example, to non-transitorily store the computer instructions that, when executed by the control circuit 109, cause the control circuit 109 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 an erasable programmable read-only memory (EPROM).)
If desired, this control circuit 109 can also operably couple to the aforementioned radiation-therapy machine 101 to thereby control, for example, the operation and/or movement of the radiation source 102 during a radiation-treatment session.
At this point it may be helpful to note some additional specific details regarding the ordinary manner of use of such a radiation-therapy machine 101.
The present teachings contemplate something quite different in these regards. In particular, and referring now to
By one approach the control circuit 109 maintains the described relationships even as the radiation source 102 moves along its arcuate path 301. By way of illustration,
Persisting the described relationships can be accomplished by selective movement of the patient's treatment volume with respect to the radiation-therapy machine 101. This movement can be achieved by moving the radiation-therapy machine 101 itself, or by moving the patient, or by moving both the radiation-therapy machine 101 and the patient. As the radiation head is constrained to a single plane during a treatment session the present teachings contemplate moving the patient during the treatment session to accomplish the desired movement of the patient's treatment volume.
As noted above, the control circuit 109 maintains the predetermined offset distance, at least in part, by selective movement of the patient-support platform 108.
Those skilled in the art will appreciate that the use of the predetermined offset distance in turn facilitates controlling the selective movement of the patient-support platform 108 such that during a radiation treatment session, and as the radiation source 102 traverses its own pathway, the patient's radiation-treatment target volume 302 moves (with respect to the isocenter 105) along a predetermined trajectory (i.e., a continguous path). By one approach this predetermined trajectory is constrained to a preselected geometric volume. If desired, this constraint can comprise constraining the predetermined trajectory to a peripheral surface of the preselected geometric volume.
Referring now to
It will be understood that the entire target volume 302 will not typically fit within the space afforded by such a point on the sphere's surface. Instead, that point (and, indeed, the aforementioned predetermined offset distance “X”) will typically have some predetermined assigned relationship with respect to the treatment volume. For example, by one approach point 701 on the sphere's surface can correspond to some specifically identified point as corresponds to the treatment volume (such as, but not limited to, a geometric center of the treatment volume).
As the radiation source 102 moves about the isocenter 105 during a radiation treatment session, the control circuit 109 manipulates the patient-support platform 108 to move in a way that moves the target volume 302 along a predetermined trajectory on the surface of the sphere 702. Doing this properly, of course, will, amongst other things, achieve the aforementioned maintenance of the predetermined offset distance “X” between the target volume 302 and the isocenter 105.
In addition, however, such an approach can have the salutary effect of changing the plane of the radiation source's fan beam with respect to the patient. By changing this relative plane, of course, the radiation treatment can provide a desired dose of radiation to the treatment volume while simultaneously exposing an overall greater quantity of non-targeted patient material to a same aggregated amount of untargeted radiation. As a result, any given non-targeted volume will tend to receive a smaller collateral dose as compared to prior art techniques in these regards.
As noted above, while a sphere-shaped volume serves as a useful illustrative example (and in fact offers a number of benefits in terms of simplifying the calculation of a particular trajectory for a specific radiation-treatment plan), these teachings will readily accommodate other shapes. This can include both relatively-symmetrical shapes (such as the aforementioned sphere, a cube, and so forth) as well as arbitrary and/or non-symmetrical shapes of convenience. There may be certain patients who present particular targeting challenges, for example, that are best served by seemingly-random blob-like volumes having a surface shape that happens to be particularly appropriate for a particular patient.
For a given radiation treatment session the specifics of the treatment as pertain to the shape of the aforementioned volume, the predetermined offset distance, the trajectory to employ, and other corresponding system parameters and settings are specified by the corresponding radiation treatment plan. As is known in the art, treatment plans typically serve to specify any number of operating parameters as pertain to the administration of such a treatment with respect to a given patient. For example, many treatment plans provide for exposing the target volume to possibly-varying dosages of radiation from a number of different directions using variable beam shapes.
Such treatment plans are often optimized prior to use. (As used herein, “optimization” will be understood to refer to improving upon a candidate treatment plan without necessarily ensuring that the optimized result is, in fact, the singular best solution.) Many optimization approaches use an automated incremental methodology where various optimization results are calculated and tested in turn using a variety of automatically-modified (i.e., “incremented”) treatment plan optimization parameters. Such an approach can serve well in the present regards.
Referring to
So configured, the control circuit 1101 can optimize a radiation-therapy treatment plan that specifies a treatment session that includes controlling selective movement of a patient-support platform such that during a least a portion of the planned radiation treatment session the patient's radiation-treatment target volume is maintained at a predetermined offset distance away from the radiation-treatment isocenter. Such a plan can further specify, as described above, a particular trajectory corresponding to relative movement of the treatment volume with respect to the radiation-treatment machine's isocenter, which trajectory can be constrained as appropriate to the surface of a geometric volume of choice per the foregoing.
If and as desired, such a control circuit 1101 can optionally operably couple to one or more user interfaces 1103 of choice. This user interface 1103 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.
Such a control circuit 1101 can also optionally communicatively couple to one or more networks 1104 including any of a variety of intranets and extranets (such as but not limited to the Internet). So configured, the control circuit 1101 can, for example, share a particular optimized radiation-treatment plan with other users, facilities, or the like.
So configured, a patient (and hence the patient's target volume) moves via a predetermined series of patient-support platform movements with respect to a radiation-treatment machine to thereby greatly facilitate exposing the target volume to radiation fan beams in more than a single plane during the course of a single treatment session. These teachings will accommodate a wide variety of modifications to thereby meet any number of challenges and requirements that are, at present, difficult or impossible to accomplish.
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. As but one example in these regards, if desired a single radiation-treatment session could use, during a first portion of the session, a first set of selected parameters for the aforementioned predetermined offset distance, predetermined trajectory, and shape of the preselected geometric volume, and then switch to using, during a second subsequent portion of the session, a second set of different selected parameters for these particular settings and selections.
