Patent Description:
US <NUM>'<NUM>'<NUM> describes a structure for controlling the roll of a patient's leg with a concave shell frame positioned on two rollers.

The following detailed description refers to the accompanying drawings. The following detailed description does not limit the invention.

A technique, in the field of radiation oncology, for holding body parts in a fixed position uses heat-formable structures that include a sheet of retention material that is stretched over the body part of the patient. For example, for performing radiation treatment of a brain tumor, the heat-formable structure includes a mask having a sheet of retention material that is stretched over the patient's face. To form the mask over the patient's face, a hot water bath or oven may be first used to heat the material of the heat-formable structure such that the sheet of material becomes pliable and deformable. The heat-formable mask is then stretched over the patient's face, and the mask is allowed to cool and harden, permanently forming the mask to the shape of the face of the patient. As an example, a mask having a sheet of thermoplastic retention material, after heating, may be stretched over a patient's face, and then allowed to cool. Upon cooling, the mask, formed to the patient's face, creates a structure that can be used to hold the patient's head in a fixed position during radiation treatments.

After the sheet of thermoplastic retention material of the mask is stretched over the body part of the patient, a frame portion of the mask is attached to a patient support table using an attachment mechanism. Once attached to the support table, however, existing patient masks cannot correct for the incorrect positioning of the patient's body part. Additionally, when the mask frame is attached to the patient support table, the thermoplastic retention material must be stretched a large distance to reach from an upper surface of the patient body (e.g., the patient's face) part all the way down to the surface of the support table. Stretching the thermoplastic retention material to this extent makes it thinner and less rigid than may be desirable.

Exemplary embodiments described herein relate to a body part immobilization device that includes improvements over existing mask frame support and attachment structures. Exemplary embodiments described herein include a deep shell frame that receives and positions a body part, where the shell has an inner shape that conforms to the shape of the body part being immobilized (e.g., a patient's head). The shell frame additionally may contain a cushion (e.g., head cushion) that is customized to fit the body part of the patient. For example, when the body part is a patient's head, the depth of the shell frame enables the customized cushion to surround the head up to a mid-point of the head, providing a large contact surface area that permits a substantial area of support for the head. The shell frame may additionally include an upper flange that permits "easy on/easy off" attachment of a mask frame to the flange. Docking of the mask frame at the upper flange of the shell frame eliminates the need to stretch the thermoplastic material of the mask all the way down to the support table surface, thereby, enhancing the thickness and rigidity of the mask material.

Exemplary embodiments described herein additionally include a support base, and a pitch adjustment mechanism and/or roll adjustment mechanism that, when coupled to the shell frame, enable a pitch and/or roll of the shell frame to be adjusted relative to the support base. Adjustment of the pitch and/or roll of the shell frame enables a positioning of the body part (e.g., positioning of the head within the immobilization device) to be easily adjusted, to satisfy the positioning requirements of the particular medical test or medical treatment being performed, without having to disconnect the mask frame from the shell frame, or without having to remove the mask frame from the body part being immobilized. The pitch adjustment mechanism and/or the roll adjustment mechanism, as described herein, may include a locking mechanism that locks the pitch and/or the roll of the shell frame relative to the support base. The pitch adjustment mechanism, as further described herein, may also include a calibrated pitch adjustment wheel that operates, in conjunction with pitch adjustment slots or notches formed in a bottom surface of the shell frame, to permit the pitch adjustment to be adjusted in a precise and controlled manner. The precise pitch adjustment is performed, using the pitch adjustment wheel, by performing a "click by click" engagement of teeth of the pitch adjustment wheel with the pitch adjustment slots or notches as the pitch adjust wheel is rotated.

A "mask," as referred to herein, includes any structure having a material (e.g., a thermoplastic material) that can be pulled over any body part of a patient to form fit the material to the body part. In some embodiments, a "mask" enables the body part to be immobilized and held in a specific position using a fastening mechanism(s) that may, or may not, be a component of the mask. Thus, a "mask," as used herein, does not refer solely to a structure for placement over a patient's face or head, but includes any type of structure for placement over any body part, or any portion of the body, of a patient (e.g., a structure that pulls over a pelvis of a patient).

<FIG> depict views of a first exemplary embodiment in which a body part immobilization device <NUM> is configured to immobilize a head <NUM> of a patient. As shown in <FIG>, immobilization device <NUM> includes a support base <NUM> and a shell frame <NUM>. Shell frame <NUM> may include an approximate half shell structure having an inner surface that is configured to conform to a back of the patient's head and neck. The half shell structure of shell frame <NUM> has a shape that approximates half of a three-dimensional spheroid, where the half roughly transects a vertical center of the spheroid. Shell frame <NUM> may include a neck cutout <NUM> in one side of the shell frame <NUM> that is configured to conform to the neck <NUM> of the patient and enables, when the patient's head <NUM> is laid within shell frame <NUM>, the neck <NUM> to extend out of the interior of shell frame <NUM>. As shown, support base <NUM> includes a first pitch shell ramp <NUM> and a second pitch shell ramp <NUM> that are disposed on support base <NUM> opposite one another and at a sufficient distance apart to enable the lower surface of shell frame <NUM> to rest upon support base <NUM> between the two pitch shell ramps when in a horizontal, non-pitch adjusted position. Pitch shell ramp <NUM> and pitch shell ramp <NUM> include sloping ramps that extend downwards towards a center of support base <NUM>. Shell frame <NUM> and support base <NUM> may be formed from various types of materials, including metal, plastic, carbon fiber, or a composite material. Shell frame <NUM> and support base <NUM> may each be formed from a same type of material, or a different type of material. For example, support base <NUM> may be formed from metal, and shell frame <NUM> may be formed from a composite material.

<FIG> depict examples of the adjustment of a pitch of shell frame <NUM> relative to support base <NUM>. As shown in the three-dimensional view of <FIG>, and the one-dimensional side view of <FIG>, pitch adjustment involves the movement (i.e., sliding) of a bottom surface of shell frame <NUM> up an upper surface of pitch ramp <NUM> (and down an upper surface of pitch ramp <NUM>), or up the upper surface of pitch ramp <NUM> (and down the upper surface of pitch ramp <NUM>. As further shown in <FIG>, movement of the bottom surface of shell frame <NUM> up pitch ramp <NUM> causes the side of shell frame adjacent the lower portion of the head <NUM> of the patient to pitch upwards and the side of the shell frame <NUM> adjacent the upper portion of the head <NUM> to pitch downwards. As also shown in <FIG>, movement of the bottom surface of shell frame <NUM> up pitch ramp <NUM> causes the side of shell frame <NUM> adjacent the upper portion of the head <NUM> of the patient to pitch upwards and the side of the shell frame <NUM> adjacent the lower portion of the head <NUM> to pitch downwards.

As depicted in <FIG>, a head cushion <NUM> may be placed within shell frame <NUM> to cushion the patient's head <NUM> (not shown) against shell frame <NUM>. Given the deep nature of shell frame <NUM>, the head cushion <NUM> surrounds the head <NUM> (not shown) up to a top of shell frame <NUM>, thus, providing a large contact surface area and good support for the head <NUM>. With the head <NUM> supported upon head cushion <NUM>, a mask <NUM> and mask frame <NUM> may be docked to shell frame <NUM> using various fastening mechanisms. In the exemplary embodiment depicted in <FIG>, multiple spring clips <NUM> may be used to fasten mask frame <NUM> to shell frame <NUM>. The multiple spring clips <NUM> may be integral to the mask frame <NUM>, may be integral to the shell frame <NUM>, or may be separate and detached items that can be used to fasten mask frame <NUM> to shell frame <NUM> when mask frame <NUM> is docked with shell frame <NUM>.

<FIG> depict further details of the pitch adjustment mechanism, and shell frame <NUM> to support base <NUM> interface components, involved in pitch adjustment of shell frame <NUM> of the body part immobilization device <NUM>. As shown in <FIG>, a pitch adjustment mechanism <NUM>, exemplary details of which are described further below, may be located on an underside of pitch ramp <NUM> of support base <NUM>. Pitch adjustment mechanism <NUM> controls the adjustment of the pitch of shell frame <NUM> relative to support base <NUM>. As shown in <FIG>, shell frame <NUM> rests in contact with support base <NUM> in a nominal horizontal position in which a center line of shell frame <NUM> is equidistant between pitch ramps <NUM> and <NUM>. A channel retention tab <NUM> may mount to support base <NUM>, on each side of shell frame <NUM> (only one tab <NUM> depicted in <FIG>), to "channel" or restrict movement of shell frame <NUM> by preventing sideways movement and permitting movement in a single dimension that includes movement up or down either of pitch ramps <NUM> and <NUM>. In other embodiments, other guide structures may be used in lieu of channel retention tabs <NUM>, such as ribs or rails formed into an upper surface of support base <NUM> between pitch ramps <NUM> and <NUM>.

<FIG> and <FIG> depict the shell frame <NUM> to support base <NUM> interface components involved in pitch adjustment of shell frame <NUM>. As shown in <FIG>, an upper flange of an adjustment fastener <NUM> of the pitch adjustment mechanism <NUM> rests against an upper surface within a lower point within the shell frame <NUM>, where the adjustment fastener <NUM> extends through the shell frame <NUM> into the support base <NUM> below. Shell movement pins <NUM> include upper flanges that rest against the upper surface at multiple locations within the shell of shell frame <NUM>. Shell movement pins <NUM> extend through shell frame <NUM> into shell movement slots (not shown in <FIG>) of support base <NUM>. Referring to <FIG>, shell movement pins <NUM> are depicted as extending through shell frame <NUM> into shell movement slots <NUM> located within pitch ramps <NUM> and <NUM> of support base <NUM>. Shell movement slots <NUM> permit movement of shell movement pins <NUM> such that shell frame <NUM> can move up and/or down pitch ramps <NUM> and <NUM> via use of pitch adjustment mechanism <NUM>.

<FIG> show immobilization device <NUM> as including a pitch adjustment mechanism <NUM> for use in adjusting a pitch of shell frame <NUM> relative to support base <NUM>, with further details of an exemplary embodiment of pitch adjustment mechanism <NUM> being shown below with respect to <FIG>. However, in another implementation, pitch adjustment mechanism <NUM> may be removed from immobilization device <NUM> such that there is no pitch adjustment mechanism <NUM> for use in adjusting the pitch of shell frame <NUM>. In this implementation, a user may merely apply manual force to shell frame <NUM> to cause the pitch of shell frame <NUM> to change relative to support base <NUM>, without having to use any type of pitch adjustment mechanism <NUM>. Furthermore, in this implementation, shell movement pins <NUM> may include lower flanges (or other means of retaining shell movement pins <NUM> within shell movement slots <NUM>), in addition to upper flanges, that retain shell frame <NUM> within shell movement slots <NUM> such that shell frame <NUM> and shell movement pins <NUM> do not easily come out of shell movement slots <NUM>.

Though not depicted in <FIG>, immobilization device <NUM> may additionally include pitch adjustment reference markers located upon either support base <NUM> and/or shell frame <NUM> that enable a visual inspection of a quantifiable amount of how much the pitch of shell frame <NUM> has been adjusted in either direction (i.e., up or down). These pitch adjustment reference markers, therefore, enable accurate and precise adjustments of the pitch of shell frame <NUM> to be made using a visual inspection. In one implementation, the pitch adjustment reference markers may be included upon a sticker that is applied at an appropriate location upon either support base <NUM> or shell frame <NUM> to show how much pitch has been applied to shell frame <NUM>. In another implementation, the pitch adjustment reference marks may be applied along a side surface of pitch ramp <NUM>, and correspondingly along a lower side surface of shell frame <NUM>. Thus, movement of the pitch adjustment reference marks applied to the lower side surface of shell frame <NUM> relative to pitch adjustment reference marks applied to the side surface of pitch ramp <NUM>, as the pitch of shell frame <NUM> is adjusted, enable a visual inspection to ascertain an amount of pitch applied to shell frame <NUM> relative to support base <NUM>. Other locations upon shell frame <NUM> and/or support base <NUM> may be used for applying pitch adjustment reference markers.

<FIG> depict four different views of support base <NUM>, including a top view in <FIG>, a side view in <FIG>, a rear view in <FIG>, and a front view in <FIG>. As can be seen in the views of <FIG>, a roughly flat and planar lower member of support base <NUM> connects to opposing pitch ramps <NUM> and <NUM>. Rearward pitch ramp <NUM> may have approximately twice the height of forward pitch ramp <NUM>, and each of pitch ramps <NUM> and <NUM> may have concave inner ramps that extend from the planar lower member of support base <NUM> to a top of pitch ramps <NUM> and <NUM>. Pitch ramps <NUM> and <NUM> may be formed integrally to support base <NUM> (i.e., formed from the same material and formed as a single structure), or may be formed as separate components, and then connected to support base <NUM> (e.g., snapped into place upon support base <NUM>). As shown in <FIG>, a pitch adjustment slot <NUM> extends through pitch ramp <NUM>, and is approximately centered upon the concave inner surface of pitch ramp <NUM>. Pitch adjustment slot <NUM> extends a certain length down the concave inner surface of pitch ramp <NUM> and sets the maximum adjustment distance that the pitch of shell frame <NUM> may be adjusted. As can further be seen in <FIG>, two shell movement slots <NUM> extend through pitch ramp <NUM>, and are located towards each outer edge of pitch ramp <NUM> and towards a lower portion of the concave inner surface of pitch ramp <NUM>. <FIG> further depicts pitch ramp <NUM> from an opposite side to that shown in <FIG>. In this front view, pitch adjustment slot <NUM> and shell movement slots <NUM> are shown extending through the concave inner surface of the pitch ramp <NUM>. A rear of pitch ramp <NUM> can further be seen in <FIG>.

<FIG> depict four different views of shell frame <NUM> of device <NUM>, including a top view in <FIG>, a side view in <FIG>, a rear view in <FIG>, and a front view in <FIG>. As can be seen in the views of <FIG>, shell frame <NUM> includes a half shell structure having an inner surface that is configured to conform to a back of the patient's head and neck. The half shell structure of shell frame <NUM> has a shape that approximates half of a three-dimensional spheroid, where the half roughly transects a center of the spheroid. Shell frame <NUM> may include a neck cutout <NUM> in one side of the shell frame <NUM> that includes an opening in the half shell that is configured to conform to the neck <NUM> of the patient and enables, when the patient's head <NUM> is laid within shell frame <NUM>, the neck <NUM> to extend out of the interior of shell frame <NUM> through the neck cutout <NUM>.

As shown in <FIG>, an upper edge of shell frame <NUM> includes a flange <NUM> that extends around a perimeter of the upper edge of the shell frame <NUM>. The flange extends approximately <NUM> to <NUM> (<NUM>/<NUM> to <NUM>/<NUM> of an inch) out from the upper edge of shell frame <NUM>. As can further be seen in <FIG>, a recessed pitch foot <NUM> is formed in a lower surface of shell frame <NUM>. Pitch foot <NUM> includes a roughly rectangular recess (as seen from the top view of <FIG>) formed in the lower surface of shell frame <NUM> that serves as the "foot" of the shell frame <NUM> that rests upon the pitch ramps <NUM> and <NUM> of the underlying support base <NUM> (not shown in <FIG>). The pitch foot <NUM> "wraps" around the convex lower surface of shell frame <NUM> and may be centered about a first center line that extends side-to-side through shell frame <NUM> and may be centered about a second center line that extends front-to-back through shell frame <NUM>.

As further seen in <FIG>, pitch foot <NUM> further includes a pitch adjustment fastener retention hole <NUM> and multiple shell movement pin retention holes <NUM>. Pitch adjustment fastener retention hole <NUM> retains a pitch adjustment fastener (described below) of the pitch adjustment mechanism <NUM>, where the pitch adjustment fastener extends through retention hole <NUM>, and through pitch adjustment slot <NUM> in support base <NUM>. Further details of the exemplary pitch adjustment mechanism <NUM> are described below with respect to <FIG>. Shell movement pin retention holes <NUM> retain shell movement pins <NUM> (shown in <FIG> and <FIG>) that extend through retention holes <NUM>, and through shell movement slots <NUM> (shown in <FIG>) in the pitch ramps <NUM> and <NUM> of support base <NUM>. Shell movement pins <NUM> (not shown in <FIG>) each include an upper flange that rests against the inner surface of shell frame <NUM> within pitch foot <NUM>. The upper flange of each shell movement pin <NUM>, in combination with the retention hole <NUM> each pin extends through, hold each shell movement pin <NUM> in place within shell frame <NUM>.

<FIG> depicts further exemplary details of flange <NUM> of shell frame <NUM>. As shown, an upper surface of flange <NUM> includes multiple registration holes <NUM>, and multiple registration tabs <NUM> for docking a frame of a body part mask (not shown) to shell frame <NUM>. The frame of the body part mask (not shown) may include multiple pins, on an underside of the frame, that line up with, and can be inserted into, registration holes <NUM>. The frame of the body part mask (not shown) may further include its own registration holes, which extend through the frame and line up with, and can be inserted over, registration tabs <NUM>. Therefore, when docking the body part mask to shell frame <NUM>, the registration holes <NUM> and registration tabs <NUM>, ensure the proper positioning of the body part mask relative to shell frame <NUM>.

<FIG> depict details of an exemplary embodiment of pitch adjustment mechanism <NUM>. <FIG> depicts a view of the overall operation of pitch adjustment mechanism <NUM>, that doesn't show shell frame <NUM> for purposes of simplicity. As shown, an adjustment fastener <NUM> of pitch adjustment mechanism <NUM> extends through pitch adjustment slot <NUM> of support base <NUM>. Movement of pitch adjustment mechanism <NUM>, to adjust the pitch either to the left or to the right in <FIG>, correspondingly causes shell movement pins <NUM> (which are attached to shell frame <NUM>) to move to the left or to the right in pitch movement slots <NUM>. Movement of shell movement pins <NUM> within pitch movement slots <NUM> results in shell frame <NUM> (not shown in <FIG>) moving in a "channel" created by channel retention tabs <NUM> that prevent any sideways movement of shell frame <NUM>. <FIG> illustrates the pitch adjustment mechanism <NUM> of <FIG> in an "exploded view" such that the individual components can be discerned. <FIG> further depicts a close up of the "exploded view" of the pitch adjustment mechanism <NUM> of <FIG>. Pitch adjustment mechanism <NUM>, in this embodiment, includes four components, an adjustment fastener <NUM>, a locking spacer <NUM>, an adjustment/locking knob <NUM>, and an adjustment pin (not shown).

Locking spacer <NUM> includes a spacer hole <NUM>. An additional break out view <NUM> of locking spacer <NUM> is depicted in <FIG>, showing the size of spacer hole <NUM> relative to the shape and size of spacer <NUM>. Locking spacer <NUM> has an oval shape, with an oval shaped spacer hole <NUM> centered within the oval shape of spacer <NUM>. Locking spacer <NUM> has a thickness of approximately <NUM> (<NUM>/<NUM> of an inch), and may be formed from various types of materials, such as metal, plastic, carbon fiber, or a composite material. The oval shaped spacer hole <NUM> has a size that permits insertion of adjustment fastener <NUM> through spacer hole <NUM>.

Adjustment fastener <NUM> further includes a fastener body <NUM>, a flange <NUM>, and a fastener pin retention hole <NUM>. Additional break out views <NUM> and <NUM> of adjustment fastener <NUM> are depicted in <FIG>, showing the shape of adjustment fastener <NUM> from different viewing angles. Fastener body <NUM>, as shown in the front break out view <NUM>, has an oval shape for insertion through the oval spacer hole <NUM> of locking spacer <NUM>. Fastener pin retention hole <NUM> permits an adjustment pin (not shown) to be inserted into the retention hole <NUM>, as described further below. Flange <NUM> is disposed at one end of fastener body <NUM>, and pin retention hole <NUM> is disposed close to another end of fastener body <NUM>. Flange <NUM> has an oval shape that is larger than the oval shape of fastener body <NUM>, such that flange <NUM> extends outwardly from the outer surface of fastener body <NUM>.

Adjustment/locking knob <NUM> further includes an adjustment body <NUM>, a pin retention hole <NUM>, an adjustment knob <NUM>, and a locking extension <NUM>. A break out view <NUM> of adjustment/locking knob <NUM> is also depicted in <FIG>, showing a fastener slot <NUM> that receives a portion of fastener body <NUM> that includes the fastener pin retention hole <NUM>. To combine knob <NUM>, spacer <NUM> and fastener <NUM> to create pitch adjustment mechanism <NUM> (or to create roll adjustment mechanism <NUM> described below), fastener body <NUM> is inserted through hole <NUM> of spacer <NUM> and into fastener slot <NUM> such that pin retention hole <NUM> lines up with pin retention hole <NUM>. The adjustment pin (not shown) can then be inserted through pin retention hole <NUM> of knob <NUM> into pin retention hole <NUM> of fastener <NUM> such that the adjustment pin can then serve as an "axle" about which the entirety of adjustment/locking knob <NUM> rotates when force is applied to adjustment knob <NUM>.

Adjustment knob <NUM> includes, for example, a rectangular touch surface via which force may be applied to cause the rotation of adjustment/locking knob <NUM>. Adjustment knob <NUM> connects to adjustment body <NUM>, which has a roughly cylindrical shape through which pin retention hole <NUM> extends on a forward surface, and into which fastener slot <NUM> extends on a side surface. Locking extension <NUM> connects to a side surface of adjustment body <NUM>, creating, for example, a reversed "e" shape seen in the main view depicted in <FIG>.

<FIG> depicts the interaction of the components of pitch adjustment mechanism <NUM> to lock and unlock the pitch adjustment of mechanism <NUM>. In <FIG>, the leftmost view depicts pitch adjustment mechanism <NUM> in an initial, unlocked state in which the pitch of shell frame <NUM> (not shown) may be adjusted by moving fastener body <NUM> within pitch movement slot <NUM> of support base <NUM> (also not shown in <FIG>). As force is applied to adjustment knob <NUM> (shown with an arrow in the leftmost view of <FIG>), adjustment/locking knob <NUM> rotates about the adjustment pin (not shown) inserted through pin retention hole <NUM>.

As further shown in the center view of <FIG>, as adjustment/locking knob <NUM> continues to rotate about the adjustment pin, the lower surface of knob <NUM>, including locking extension <NUM>, begins forcing locking spacer <NUM> in an upwards direction towards flange <NUM> of adjustment fastener <NUM> and also begins pulling adjustment fastener <NUM> in a downwards direction. As locking spacer <NUM> moves in the upwards direction, it applies force against the bottom surface of pitch ramp <NUM> of support base <NUM>, and as adjustment fastener <NUM> moves in the downwards direction, the flange <NUM> of adjustment fastener <NUM> is tightened against an upper surface of shell frame <NUM>. In another embodiment (not shown), adjustment/locking knob <NUM> may, instead of the reversed "e" shape shown in <FIG>, include a cam.

The rightmost view of <FIG> depicts adjustment/locking knob <NUM> in a locked position in which the force applied by locking spacer <NUM> against the bottom surface of pitch ramp <NUM> of support base <NUM>, and the force applied by flange <NUM> of adjustment fastener <NUM> against an upper surface of shell frame <NUM> causes shell frame <NUM> to be held in place, at a desired pitch position, relative to support base <NUM>. This view of <FIG> shows locking extension <NUM> in a locked position that applies the maximum upwards force against locking spacer <NUM> which, in turn, applies the maximum upwards force against the lower surface of support base <NUM>. With locking extension <NUM> in the locked position, fastener body <NUM> is pulled downwards with a maximum "position locking" force, causing flange <NUM> to apply a maximum "position locking" force against an upper surface of shell frame <NUM>. The "position locking" force caused by rotation of adjustment/locking knob <NUM> against locking spacer <NUM> locks shell frame <NUM> into a particular level of pitch. The pitch of shell frame <NUM> can be "unlocked" by reversing (i.e., starting with the rightmost view, and proceeding to the middle view, and then to the leftmost view) the rotation of adjustment/locking knob <NUM> shown in <FIG>. <FIG> shows pitch adjustment mechanism <NUM> rotated into a locked position, causing shell frame <NUM> to be held at a certain position upon pitch ramp <NUM> such that shell frame <NUM> has a certain pitch relative to support base <NUM>.

<FIG> depict details of an additional exemplary embodiment in which pitch adjustment mechanism <NUM> further includes a pitch adjustment wheel assembly that permits a precise, calibrated adjustment of the pitch of shell frame <NUM> relative to support base <NUM>. Pitch adjustment mechanism <NUM> is shown in <FIG> as including the additional pitch adjustment wheel assembly <NUM> mounted on the underside of pitch ramp <NUM> of support base <NUM>, adjacent to pitch adjustment/locking knob <NUM>.

<FIG> further shows a top view of support base <NUM> and additional details of pitch adjustment wheel assembly <NUM>. In the close-up view, pitch adjustment wheel assembly <NUM> is depicted as including a cylindrical pitch wheel <NUM> having pitch adjustment teeth <NUM> that extend through a rectangular pitch adjustment port <NUM> formed through the underside of pitch ramp <NUM>. As can be seen in subsequent figures, the teeth of pitch wheel <NUM> engage with corresponding notches/slots in the underside of shell frame <NUM>, and when pitch wheel <NUM> is rotated, cause the pitch of shell frame <NUM> to be adjusted.

<FIG> depicts further details of pitch adjustment wheel assembly <NUM>. As shown, pitch wheel <NUM> mounts to triangular wheel mounts <NUM> via a wheel axle (not shown) that extends through the wheel mount holes <NUM> in each of wheel mounts <NUM>. Pitch wheel <NUM> may, therefore, rotate in a clockwise, or counterclockwise, direction by rotating about the wheel axle and wheel mount holes <NUM>. As pitch wheel <NUM> rotates, the teeth of pitch wheel <NUM> that extend through pitch adjustment port <NUM> in pitch ramp <NUM>, engage, as described further below with respect to <FIG>, the underside of shell frame <NUM> causing the pitch of shell frame <NUM> to be adjusted in periodic, discrete increments.

<FIG> depicts further details of the teeth of pitch wheel <NUM> adjusting the pitch of shell frame <NUM>. As seen in <FIG>, shell frame <NUM> includes a series of pitch adjustment slots <NUM> that are formed from the underside of shell frame <NUM> through to the upper surface of shell frame <NUM>. The pitch adjustment slots <NUM> match the shape and size of the teeth <NUM> of pitch wheel <NUM> located beneath shell frame <NUM> on the underside of support base <NUM>. As pitch wheel <NUM> is rotated in a clockwise direction, the teeth <NUM> of pitch wheel <NUM> engage pitch adjustment slots <NUM> and cause shell frame <NUM> to move downwards (to the right), in the close up view of <FIG>. Further, as pitch wheel <NUM> is rotated in a counter clockwise direction, the teeth <NUM> of pitch wheel <NUM> engage pitch adjustment slots <NUM> and cause shell frame <NUM> to move upwards (to the left), in the close-up view of <FIG>. Each "click by click" adjustment of pitch wheel <NUM> causes a precise adjustment (e.g., <NUM>°, <NUM>°, etc.) of the pitch of shell frame <NUM> via interaction of the teeth <NUM> of pitch wheel <NUM> with the pitch adjustment slots <NUM> of shell frame <NUM>.

<FIG> depicts a cross-sectional cutaway view of pitch adjustment wheel assembly <NUM>. As pitch wheel <NUM> is rotated in a clockwise direction ("CW"), the teeth <NUM>, extending through pitch adjustment port <NUM> in pitch ramp <NUM>, engage with the pitch adjustment slots <NUM> in the bottom surface of shell frame <NUM>. Engagement of the teeth <NUM> of pitch wheel <NUM> with pitch adjustment slots <NUM> causes shell frame <NUM> to move upwards, in the view shown in <FIG>, as pitch wheel <NUM> is rotated clockwise. Alternatively, as pitch wheel <NUM> is rotated in a counter-clockwise (CCW) direction, the teeth <NUM>, extending through pitch adjustment port <NUM> in pitch ramp <NUM>, engage with the pitch adjustment slots <NUM> in the bottom surface of shell frame <NUM>. Engagement of the teeth <NUM> of pitch wheel <NUM> with pitch adjustment slots <NUM> causes shell frame <NUM> to move downwards, in the view shown in <FIG>, as pitch wheel <NUM> is rotated counter clockwise.

<FIG> illustrates another exemplary embodiment of a body part immobilization device <NUM> that includes, in addition to a pitch adjustment mechanism, a roll adjustment mechanism that permits the shell frame <NUM> (and the patient body part placed within the shell frame <NUM>), to be "rolled" relative to the support base <NUM> of the device <NUM>. As shown in <FIG>, body part immobilization device <NUM> includes a support base <NUM> and a shell frame <NUM> similar to the embodiment of <FIG>. Shell frame <NUM> may include an approximate half shell structure having an inner surface that is configured to conform to a back of the patient's body part (e.g., head and neck). In the implementation depicted in <FIG>, the half shell structure of shell frame <NUM> has a shape that approximates half of a three-dimensional spheroid, where the half roughly transects a vertical center of the spheroid. Shell frame <NUM> may include a cutout <NUM> in one side of the shell frame <NUM> that is configured to conform to the body part (e.g., neck or other body part) of the patient and enables, when the patient's body part (e.g., head) is laid within shell frame <NUM>, the attaching body component (e.g., neck) to extend out of the interior of shell frame <NUM>. Support base <NUM> may be configured similarly to that shown, and described, above with respect to body part immobilization device <NUM>.

As shown in <FIG>, device <NUM> further includes a shell frame carriage <NUM> upon which shell frame <NUM> rests. Shell frame carriage <NUM> rests upon first pitch ramp <NUM> and second pitch ramp <NUM>, which are further disposed on support base <NUM> opposite one another and at a sufficient distance apart to enable the lower surface of shell frame carriage <NUM> to rest upon support base <NUM> between the two pitch ramps <NUM> and <NUM> when oriented in a horizontal, non-pitch adjusted position. Pitch ramp <NUM> and pitch ramp <NUM> include sloping ramps that extend downwards towards a center of support base <NUM>. Shell frame <NUM>, shell frame carriage <NUM>, and support base <NUM> may be formed from various types of materials, including, for example, metal, plastic, carbon fiber, and/or a composite material. Shell frame <NUM>, shell frame carriage <NUM>, and support base <NUM> may each be formed from a same type of material, or a different type of material. For example, support base <NUM> may be formed from metal, and shell frame <NUM> and shell frame carriage <NUM> may be formed from a plastic or a composite material. As shown in <FIG>, and described in further detail below, device <NUM> includes a pitch adjustment mechanism <NUM> for adjusting the pitch of shell frame <NUM> and shell frame carriage <NUM>, and additionally includes a roll adjustment mechanism <NUM> for adjusting the roll of shell frame <NUM>.

<FIG> depicts an exploded three-dimensional view of body part immobilization device <NUM> of <FIG>. Support base <NUM> includes a similar physical configuration to that described with respect to device <NUM> of <FIG> above. Shell frame carriage <NUM> includes a tray-like shape having an upper surface that conforms to the spheroid lower surface of shell frame <NUM>, and a lower surface that conforms to the upper surface of support base <NUM>, including the upper surface of pitch ramp <NUM> and pitch ramp <NUM>. As shown, the lower surface of shell frame carriage <NUM> rests upon the upper surface of support base <NUM>, including resting on the upper surfaces of pitch ramp <NUM> and pitch ramp <NUM>. The lower surface of shell frame <NUM> rests upon the upper surface of shell frame carriage <NUM>, with shell movement pins <NUM> extending through holes in shell frame <NUM> into corresponding shell movement slots (described in further detail below) in shell frame carriage <NUM>. Pitch adjustment mechanism <NUM> enables the adjustment of the pitch of shell frame carriage <NUM>, which further adjusts the pitch of shell frame <NUM> that rides within shell frame carriage <NUM>. Roll adjustment mechanism <NUM> enables the adjustment of the roll of shell frame <NUM> within shell frame carriage <NUM>.

<FIG> is a three-dimensional view of the components of body part immobilization device <NUM> that are involved in adjustment of the pitch of shell frame carriage <NUM> and shell frame <NUM>. As shown in the main view of <FIG>, carriage movement pins <NUM> extend through corresponding holes in shell frame carriage <NUM> into movement slots <NUM> within pitch ramp <NUM> and pitch ramp <NUM>. As further depicted in the break-out view of <FIG>, adjustment fastener <NUM> of pitch adjustment mechanism <NUM> extends through a hole <NUM>, in a rear surface of shell frame carriage <NUM>, that is located so as to align with pitch adjustment slot <NUM> within pitch ramp <NUM>. Locking spacer <NUM> fits over adjustment fastener <NUM>, and adjustment/locking knob <NUM> fits over, and attaches to, adjustment fastener <NUM>. Operation of adjustment/locking knob <NUM> may enable the pitch of shell frame carriage <NUM> and shell frame <NUM> to be "locked" into a certain pitch position. Operation of the pitch adjustment of body part immobilization device <NUM> is described in further detail below with respect to <FIG> and <FIG>.

<FIG> is a three-dimensional view of the components of body part immobilization device <NUM> that are involved in adjustment of the roll of shell frame <NUM>. As shown in the main view of <FIG>, shell movement pins <NUM> extend through corresponding holes in shell frame <NUM> into movement slots <NUM> within shell frame carriage <NUM>, where movement slots <NUM> are oriented in a transverse direction to movement slots <NUM> in pitch ramps <NUM> and <NUM>. As further depicted in the break-out view of <FIG>, adjustment fastener <NUM> of roll adjustment mechanism <NUM> extends through a roll fastener hole <NUM> within shell frame <NUM>, and through a corresponding hole <NUM> in a forward surface of shell frame carriage <NUM> that is aligned with the roll fastener hole <NUM> within shell frame <NUM>. Hole <NUM> in shell frame carriage <NUM> is sized larger than roll fastener hole <NUM> in shell frame <NUM> to permit rotational "roll" movement of shell frame <NUM>. Locking spacer <NUM> fits over adjustment fastener <NUM>, and adjustment/locking knob <NUM> fits over, and attaches to, adjustment fastener <NUM> such as described with respect to <FIG> above. Operation of adjustment/locking knob <NUM> may enable the roll of shell frame <NUM>, within shell frame carriage <NUM>, to be "locked" into a certain roll position. Operation of the roll adjustment of body part immobilization device <NUM> is described in further detail below with respect to <FIG> and <FIG>.

<FIG> depict four different views of shell frame <NUM> of body part immobilization device <NUM>, including a top view in <FIG>, a side view in <FIG>, a rear view in <FIG>, and a front view in <FIG>. As can be seen in the views of <FIG>, shell frame <NUM> includes a half shell structure having an inner surface that is configured to conform to a back of the patient's head and neck. The half shell structure of shell frame <NUM> has a shape that approximates half of a three-dimensional spheroid, where the half roughly transects a center of the spheroid. Shell frame <NUM> may include a neck cutout <NUM> in one side of the shell frame <NUM> that includes an opening in the half shell that is configured to conform to the neck <NUM> (not shown) of the patient and enables, when the patient's head <NUM> (not shown) is laid within shell frame <NUM>, the neck <NUM> (not shown) to extend out of the interior of shell frame <NUM> through the neck cutout <NUM>.

As shown in <FIG>, an upper edge of shell frame <NUM> includes a flange <NUM> that extends around a perimeter of the upper edge of the shell frame <NUM>. The flange <NUM> extends approximately <NUM> to <NUM> (<NUM>/<NUM> to <NUM>/<NUM> of an inch) out from the upper edge of shell frame <NUM>. As can further be seen in <FIG>, shell frame <NUM> includes two shell movement pin holes <NUM> located in the vicinity of the bottom of shell frame <NUM>. Shell movement pin holes <NUM> receive corresponding shell movement pins <NUM> (not shown) and line up with respective movement slots <NUM> (not shown) within shell frame carriage <NUM> (not shown). <FIG> further depict roll fastener hole <NUM> and rotation hole <NUM>. Though not shown in <FIG>, adjustment fastener <NUM> of roll adjustment mechanism <NUM> extends through roll fastener hole <NUM> into hole <NUM> in shell frame carriage <NUM>, and a fastening mechanism, such as, for example, a screw and nut, extends through rotation hole <NUM> to rotatably fasten shell frame <NUM> to shell frame carriage <NUM> such that shell frame <NUM> may rotate about a central axis formed within rotation hole <NUM> as the roll of shell frame <NUM> is adjusted relative to shell frame carriage <NUM> and support base <NUM>. Flange <NUM> of device <NUM> may be similar to flange <NUM> of device <NUM>, with multiple registration and alignment holes being disposed around a perimeter of flange <NUM>, and with each registration hole extending from an upper surface of flange <NUM> through to a lower surface of flange <NUM>. The frame of the body part mask (not shown) may include multiple pins, on an underside of the frame, that line up with, and can be inserted into, the registration and alignment holes of flange <NUM>. Therefore, when docking the body part mask to shell frame <NUM>, the registration and alignment holes of flange <NUM>, in conjunction with the multiple pins on the underside of the body part mask frame, ensure the proper positioning of the body part mask relative to shell frame <NUM>.

<FIG> and <FIG> depict support base <NUM> and shell frame carriage <NUM> of device <NUM> in a horizontal position prior to any adjustment being applied to change the pitch of shell frame carriage <NUM> relative to support base <NUM>. With shell frame carriage <NUM> residing in a non-pitch adjusted position, such as shown in <FIG> and <FIG>, shell frame carriage pins <NUM> extend through corresponding holes in shell frame carriage <NUM> and into carriage movement slots <NUM> (not shown) of pitch ramps <NUM> and <NUM> at a midpoint within the length of slots <NUM>. To adjust the pitch of shell frame carriage <NUM> and shell frame <NUM>, adjustment/locking knob <NUM> of pitch adjustment mechanism <NUM> may be rotated to an "unlocked" position. As can be seen in <FIG>, when adjustment/locking knob <NUM> is rotated to a locked position, adjustment fastener <NUM> pulls shell frame carriage <NUM> against the upper surface of support base <NUM> such that shell frame carriage <NUM> (and shell frame <NUM>, which rests within carriage <NUM>) is held in a fixed pitch position relative to support base <NUM>. To adjust the pitch of shell frame carriage <NUM> and shell frame <NUM>, adjustment/locking knob <NUM> of pitch adjustment mechanism <NUM> may be rotated to an unlocked position (the opposite direction to that shown in <FIG>), loosening the hold adjustment fastener <NUM> has on shell frame carriage <NUM>. With adjustment/locking knob <NUM> rotated to an unlocked position, adjustment fastener <NUM> no longer pulls shell frame carriage <NUM> against the upper surface of support base <NUM>, thus, enabling the pitch of shell frame carriage <NUM> and shell frame <NUM> to be adjusted, as described below with respect to <FIG> and <FIG>. When the pitch of shell frame carriage <NUM> is adjusted, carriage movement pins <NUM> ride within movement slots <NUM> of support base <NUM>, either to the left or to the right, in the view depicted in <FIG>, depending on the direction of pitch being applied to shell frame carriage <NUM> and shell frame <NUM>.

<FIG> and <FIG> depict adjustment of the pitch of shell frame carriage <NUM> (and shell frame <NUM>, which rides within carriage <NUM>). In <FIG>, the rear of shell frame carriage <NUM>, and shell frame <NUM> (not shown) resting within carriage <NUM>, is pitched upwards upon pitch ramp <NUM> and the front of shell frame carriage <NUM> is simultaneously pitched downwards upon pitch ramp <NUM> by sliding the lower surface of carriage <NUM> upon pitch ramps <NUM> and <NUM>. As the pitch of shell frame carriage <NUM> is adjusted, carriage movement pins <NUM> ride within movement slots <NUM> (not shown) of support base <NUM>. Each of movement slots <NUM> has a slot length that limits that amount of pitch adjustment in either direction. In <FIG>, the rear of shell frame carriage <NUM>, and the shell frame <NUM> (not shown) resting within carriage <NUM>, is pitched downwards upon pitch ramp <NUM> and the front of shell frame carriage <NUM> is simultaneously pitched upwards upon pitch ramp <NUM> by sliding the lower surface of carriage <NUM> upon pitch ramps <NUM> and <NUM>.

<FIG> depicts shell frame <NUM>, shell frame carriage <NUM>, and support base <NUM> of device <NUM> in a horizontal position prior to any roll adjustment being applied to change the roll of shell frame <NUM> relative to shell frame carriage <NUM> and support base <NUM>. With shell frame <NUM> residing in a non-roll adjusted position, such as shown in <FIG>, shell frame pins <NUM> (not shown) extend into corresponding shell movement slots <NUM> in shell frame carriage <NUM> at a midpoint within the length of slots <NUM>. To adjust the roll of shell frame <NUM>, adjustment/locking knob <NUM> of roll adjustment mechanism <NUM> may be rotated from a "locked" position to an "unlocked" position (shown with the arrow in an upward direction in <FIG>). In the exemplary implementation depicted in <FIG>, when adjustment/locking knob <NUM> is rotated to an unlocked position, adjustment fastener <NUM> no longer pulls shell frame <NUM> against the upper surface of shell frame carriage <NUM> such that shell frame <NUM> is not held in a fixed position relative to shell frame carriage <NUM>, and the roll of shell frame <NUM> may be adjusted using roll adjustment mechanism <NUM>.

The operation of roll adjustment mechanism <NUM> is described in further detail with reference to <FIG>. In the rightmost view of <FIG>, adjustment/locking knob <NUM> is in a locked position in which the force applied by locking spacer <NUM> against the bottom surface of shell frame carriage <NUM>, and the force applied by flange <NUM> of adjustment fastener <NUM> against an upper surface of shell frame <NUM> causes shell frame <NUM> to be held in place, at a desired roll position, relative to shell frame carriage <NUM> and support base <NUM>. This rightmost view of <FIG> shows locking extension <NUM> in a locked position that applies the maximum upwards force against locking spacer <NUM> which, in turn, applies the maximum upwards force against the lower surface of shell frame carriage <NUM>. With locking extension <NUM> in the locked position, fastener body <NUM> is pulled downwards with a maximum "position locking" force, causing flange <NUM> to apply a maximum "position locking" force against an upper surface of shell frame <NUM>. The "position locking" force caused by rotation of adjustment/locking knob <NUM> against locking spacer <NUM> locks shell frame <NUM> into a particular level of roll relative to shell frame carriage <NUM>. The roll of shell frame <NUM> can be "unlocked" by reversing (i.e., starting with the rightmost view, and proceeding to the middle view, and then to the leftmost view) the rotation of adjustment/locking knob <NUM> shown in <FIG>.

<FIG> and <FIG> depict adjustment of the roll of shell frame <NUM> relative to shell frame carriage <NUM> and support base <NUM>. In <FIG>, the right side of shell frame <NUM> (viewed from the rear of shell frame <NUM>) is rolled downwards upon shell frame carriage <NUM>, and the left side of shell frame <NUM> is simultaneously rolled upwards upon shell frame carriage <NUM> by sliding the lower surface of shell frame <NUM> along the upper surface of shell frame carriage <NUM>. As the roll of shell frame <NUM> is adjusted, shell movement pins <NUM> ride within shell movement slots <NUM> of shell frame carriage <NUM>. Each of shell movement slots <NUM> has a slot length that limits that amount of roll adjustment in either direction. In <FIG>, the right side of shell frame <NUM> (viewed from the rear of shell frame <NUM>) is rolled upwards upon shell frame carriage <NUM> and the left side of shell frame <NUM> is simultaneously rolled downwards upon shell frame carriage <NUM>, by sliding the lower surface of shell frame <NUM> along the upper surface of shell frame carriage <NUM>, to roll adjust shell frame <NUM> in an opposite direction to that depicted in <FIG>. Once the roll of shell frame <NUM> has been adjusted to the desired roll position, adjustment/locking knob <NUM> of roll adjustment mechanism <NUM> may be rotated to a locked position to tighten adjustment fastener <NUM> against shell frame <NUM>. With adjustment/locking knob <NUM> rotated to a locked position, adjustment fastener <NUM> pulls shell frame <NUM> against the upper surface of shell frame carriage <NUM>, thus, holding shell frame <NUM> in a fixed roll position relative to shell frame carriage <NUM> and support base <NUM>.

<FIG> depict an exemplary embodiment of body part immobilization device <NUM> that includes both a pitch adjustment mechanism and a roll adjustment mechanism. In other embodiments, however, body part immobilization device <NUM> may include only the roll adjustment mechanism <NUM> (and associated structure), and may not include the pitch adjustment mechanism (i.e., pitch adjustment mechanism <NUM>, and associated structure, is omitted from device <NUM>).

The foregoing description of implementations provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. Although the invention has been described in detail above, it is expressly understood that it will be apparent to persons skilled in the relevant art that the invention may be modified without departing from the scope of the claims. Various changes of form, design, or arrangement may be made to the invention without departing from the scope of the claims. Therefore, the above-mentioned description is to be considered exemplary, rather than limiting, and the true scope of the invention is that defined in the following claims. For example, support base <NUM> is shown and described above as having a certain structure that allows shell frame <NUM> or shell frame carriage <NUM> to ride upon support base <NUM>. In other implementations, however, support base <NUM> may include a different type of supporting structure, such as a base plate or a couch top, having a physical configuration that also enables shell frame <NUM> or shell frame carriage <NUM> to ride upon the support base. In such implementations, the different types of supporting structure may include a matching hole pattern for adjustment pins similar to that shown in <FIG> or <FIG>.

Claim 1:
A structure for positioning a body part, comprising:
a shell frame (<NUM>) having an inner surface configured to a shape of the body part,
a support base (<NUM>) comprising a planar member, a first concave ramp (<NUM>) and an opposing, second concave ramp (<NUM>), wherein a bottom of a first slope of the first concave ramp (<NUM>) and a bottom of a second slope of the opposing, second concave ramp (<NUM>) both connect to, and are separated by, a portion of the planar member and the portion of the planar member extends between the bottom of the first slope of the first concave ramp (<NUM>) and the bottom of the second slope of the opposing, second concave ramp (<NUM>), and
wherein the shell frame (<NUM>) has an outer convex surface configured to:
ride upon, and move relative to, upper surfaces of the first concave ramp (<NUM>), the opposing, second concave ramp (<NUM>), and the planar member to enable a pitch of the shell frame (<NUM>) to be adjusted relative to the support base (<NUM>), or
ride upon, and move relative to, an upper surface of a carriage (<NUM>), that further resides upon the upper surfaces of the first concave ramp (<NUM>), the opposing, second concave ramp (<NUM>), and the planar member, to enable a roll of the shell frame (<NUM>) to be adjusted relative to the support base (<NUM>).