JP6576144B2 - Shell mounting structure and fixed position shell system - Google Patents

Description

  The present invention provides a shell mounting structure for attaching a body position fixing shell used to fix a part of a patient's head or the like placed on a base plate installed on the top surface of a treatment table to the base plate in particle beam therapy, and the shell The present invention relates to a posture fixing shell system having a mounting structure.

  A body position fixing shell used for fixing a patient, a subject's head and the like in radiation therapy or the like is formed of a net-like sheet material made of a thermoplastic resin. Place the patient etc. on the base plate fixed to the top plate such as a treatment table, press the shell softened by applying heat to the patient's head, take the mold, and use the shell after the mold is taken The parts and the like are fixed to the base plate so as not to move. Such a posture fixing shell system is disclosed in Non-Patent Document 1.

  In a commonly used position-fixing shell system for the head or head and neck, a shell that is shaped to wrap the head or head and neck is placed, and both ends of the shell extend in the direction of the head and tail. It is fixed to.

“ESFORM Product Introduction”, [online], Engineering System Co., Ltd. [searched July 24, 2014], Internet <URL: http://www.esform.com>

  Here, radiation therapy includes photon beam therapy using X-rays or gamma rays and particle beam therapy using heavy particle beams or proton beams. The heavy particle beam and proton beam used for the latter particle beam therapy have a characteristic that the dose is peaked in the deep part of the patient (Bragg peak) with little absorption on the patient's body surface, so that deep cancer tissue Can be destroyed at a pinpoint, reducing damage to surrounding normal tissue.

  In particle beam therapy, the dose and irradiation direction of the particle beam are precisely controlled so that the Bragg peak can be obtained accurately at the target cancer tissue position, and the path of particle beam from each direction is homogeneous. It is necessary to ensure that That is, as shown in FIG. 7, in the dose curves of proton beams and heavy particle beams, since the slope near the peak position is steep, the cancer tissue can be destroyed at the peak position, while the region through which the particle beam passes. If there are non-uniform structural parts such as voids, the absorbed dose varies greatly depending on the particle beam passage region due to the non-uniformity, and the peak position is shifted.

  For this reason, the fixed posture shell used for fixing the patient's head or the like is not a net-like shell as in the case of photon beam therapy, but a plate-like shell having a constant thickness. However, the shell mounting portion for mounting the shell to the base plate has a non-uniform structural portion in which gaps and the like are unevenly distributed. Conventionally, the structure of the mounting portion of the shell has a common structure in both photon beam therapy and particle beam therapy, and no consideration is given to the non-uniformity of the structure of the shell mounting portion. .

  In the mounting portion of the shell, a positioning hole and a positioning pin for positioning the shell are arranged, and a fastener and a fixing hole for fixing the positioned shell to the base plate are arranged. For this reason, the mounting portion of the shell has a non-uniform structure in which gaps, materials with different thicknesses, and the like are unevenly distributed. There is a possibility that the dose of the particle beam passing through each part of the shell mounting portion varies, and the peak dose may not be accurately administered to the treatment position.

  In view of these points, an object of the present invention is to provide a shell mounting structure suitable for use in particle beam therapy, and a body position fixing shell system including the shell mounting structure.

In order to solve the above-mentioned problems, the present invention provides a body position fixing shell used for fixing a patient's head and other parts placed on a base plate placed on the top surface of a treatment table in particle beam therapy. A shell mounting structure for mounting,
A shell mounting surface formed of a plane having a constant width formed on side end surfaces on both sides of the base plate;
A frame plate portion made of a rectangular flat plate having a width wider than the shell mounting surface and a constant thickness, formed on a plate-like shell frame fixed to the edge portions on both sides of the body posture fixing shell;
A positioning portion for positioning and overlapping the frame plate portion on the shell mounting surface;
A holding plate made of a rectangular flat plate having a constant width and the same width as the side end surface and longer than the frame plate portion;
An attaching portion for positioning and attaching the pressing plate in a state of sandwiching the frame plate portion between the shell attaching surface and the side end surface;
Have
The positioning portion can be inserted into the pin hole penetrating the frame plate portion in the thickness direction, and the protruding height corresponding to the thickness of the frame plate portion from the shell mounting surface. A positioning pin having a thickness,
The frame plate portion of the shell frame is overlapped with the positioning pin inserted into the pin hole and the pin hole is sealed with respect to the shell mounting surface, and the pressing plate is attached to the frame plate portion. And is attached to the side end face.

  In the shell mounting structure of this configuration, a frame plate portion of a certain thickness in the shell frame of the body position fixing shell is superimposed on the shell mounting surface on the side end surface of the base plate, and a pressing plate of a certain thickness is superimposed thereon. . Moreover, the pin hole of the shell frame is in a state of being blocked by the pin on the base plate side. Therefore, in the shell mounting portion, the cross section orthogonal to the side end face of the base plate is a uniform cross section having substantially the same thickness and no gap at each position in the direction along the side end face. Therefore, unlike the conventional mounting structure having a non-uniform cross-sectional structure in which gaps and the like are unevenly distributed, it is possible to suppress fluctuations in the absorbed dose of the particle beam passing through each position.

  In addition, the shell mounting structure according to the present invention is the same as the case where the structure of the mounting portion (shell frame structure) on the posture fixing shell side is used for photon beam therapy. Therefore, there is also an advantage that no change is required in the mounting portion on the side of the body position fixing shell.

Here, it is desirable that the attachment portion of the holding plate is configured as follows so that the frame plate portion of the shell frame can be attached to the side end surface of the base plate by a simple operation using the holding plate.

That is, the attaching portion of the pressing plate includes a pair of mounting pins arranged on the shell mounting surface at a wider interval than the length of the frame plate portion, and the pair of mounting pins on one long side edge of the pressing plate. And a pair of pin insertion grooves into which each mounting pin can be inserted. The mounting pin includes a leg portion embedded and fixed to the base plate from the shell mounting surface, and a stepped head formed at the tip of the leg portion and protruding from the shell mounting surface.

  Further, when the pressing plate is slid along the shell mounting surface and the mounting pin is inserted into the pin insertion groove, the stepped head portion has a concave shape surrounding the pin insertion groove in the pressing plate. The frame plate portion of the shell frame is sandwiched between the pressing plate and the shell mounting surface by engaging with the inner peripheral edge of the groove from the outside in the thickness direction, and the outer surface of the pressing plate A state is formed in which the tip surface of the stepped head is located on the same plane.

The attaching part of the pressing plate may include a pair of pin insertion holes instead of the pair of pin insertion grooves. In this case, the pin insertion hole is a long hole formed with a large hole portion having a size capable of inserting the stepped head portion on one side and a small hole portion formed on the other side.

  Further, when the insertion plate is passed through the large hole portion of the pin insertion hole and the holding plate is slid in a direction in which the insertion pin relatively moves toward the small hole portion, The stepped head of the mounting pin is engaged from the outside in the thickness direction with respect to the inner peripheral edge of the small hole portion of the pressing plate, and between the pressing plate and the shell mounting surface, The frame plate portion of the shell frame is sandwiched, and a state is formed in which the outer surface of the pressing plate and the tip surface of the stepped head are located on the same plane.

  Next, in a state where the frame plate portion of the shell frame is attached to the shell attachment surface, in order to seal a gap formed between the pressure plate and the side end surface on both sides thereof, It is desirable that a gap sealing plate having the same thickness as that of the frame plate portion of the shell frame is attached to the inner surface facing the side end surface at both end portions in the length direction.

It is sectional drawing of the base plate of the posture fixing shell system to which this invention is applied, the head mounting part of a posture fixing shell system, and the part cut | disconnected by the cc line. It is explanatory drawing which shows the attachment structure of the shell for heads of a body posture fixed shell system. Partial perspective view showing the head mounting portion of the base plate to which the insertion type holding plate is attached, explanatory view showing the attachment of the insertion type holding plate, a front view, a plan view, a rear view and a sectional view of the insertion type holding plate It is. It is the fragmentary perspective view which shows the head mounting part of the base plate which attached the slide type pressing plate, explanatory drawing which shows attachment of a slide type pressing plate, the front view of a slide type pressing plate, a top view, a rear view, and sectional drawing. It is the top view, front view, bottom view, back view, right side view, and left side view of the base plate. It is the fragmentary perspective view which shows the head mounting part of a baseplate, a fragmentary top view, and a fragmentary side view. It is a graph which shows the dose curve of a particle beam.

  Hereinafter, an embodiment of a posture fixing shell system for head fixing to which the present invention is applied will be described with reference to the drawings. In addition, this invention is applicable also to the posture fixing shell system used in order to fix patient's site | parts other than a head.

  FIG. 1A is a perspective view showing a base plate of the posture fixing shell system according to the present embodiment, and FIG. 1B is a partial perspective view showing a shell mounting structure for fixing the head. (C) is a schematic sectional drawing of the part cut | disconnected by the cc line | wire of FIG.1 (b). The posture fixing shell system 1 includes a base plate 2 and a head shell 3 for fixing a patient's head attached to the base plate 2. The base plate 2 is installed in a state of being positioned on the top surface of a treatment table (not shown).

  The base plate 2 is a carbon plate having a certain thickness, and has a wide rectangular main body portion 21 and a narrow-width head mounting portion 22 extending from a central portion of the edge of the front end side of the main body portion 21. And. The head shell 3 is made of a thermoplastic resin and a shell body 31 made of a substantially rectangular flat plate portion having a constant thickness, and a rectangular resin having a fixed width fixed to the left and right side edges of the shell body 31. The shell frame 32 is provided. FIG. 1B shows a state in which the molded head shell 3 obtained by shaping the head of a patient (not shown) is attached to the head mounting portion 22 of the base plate 2. . The head shell 3 in this example is a general one used for fixing a patient's head in particle beam therapy.

  A shell mounting structure for mounting the head shell 3 to the base plate 2 will be described below. As shown in FIGS. 1 (b) and 1 (c), the shell frame 32 of the head shell 3 after shaping so as to correspond to the shape of the head of a patient (not shown) It is fixed to the side end surfaces 23 on both sides in the width direction of the head mounting portion 22 at the front end by using the insertion-type pressing plate 4.

  2A and 2B are explanatory views of the shell mounting structure, FIG. 2A is an explanatory view showing the side end face 23 of the head mounting portion 22 of the base plate 2, and FIG. 2B is a side end face 23 of the head shell 3. It is explanatory drawing which shows the state which attached the shell frame 32, (c) is explanatory drawing which shows the state which attached the insertion type pressing plate 4, (d) is the stage for attaching the insertion type holding plate 4 It is explanatory drawing which shows an attached pin.

  As shown in FIGS. 1C and 2B, the shell frame 32 of the head shell 3 includes a frame plate 33 made of a rectangular resin flat plate having a constant thickness. An insertion groove portion 34 into which the edge end portion 31a of the shell body 31 is inserted and fixed is formed at the upper long side edge portion. The lower portion of the insertion groove portion 34 of the frame plate 33 is a frame plate portion 35 having a width slightly larger than the width of the side end surface 23 of the head mounting portion 22 of the base plate 2 (the thickness of the base plate). It has become. In the frame plate portion 35, three circular pin holes 36 for positioning are formed in the long side direction at predetermined intervals so as to pass through in the thickness direction.

  As shown in FIG. 2A, the side end surface 23 of the head mounting portion 22 of the base plate 2 is a flat side surface orthogonal to the top surface 2 a of the base plate 2, and the head shell 3 on this side end surface 23. A portion having a length range corresponding to the frame plate portion 35 is the shell mounting surface 24. On the shell mounting surface 24, three pins 25 having a circular cross section for positioning are formed in the length direction (head-to-tail direction) at a predetermined interval. The pins 25 are formed at intervals corresponding to the pin holes 36 of the head shell 3. The protruding height of the pin 25 is a dimension corresponding to the thickness of the frame plate portion 35 of the head shell 3, and the tip thereof is a flat surface parallel to the shell mounting surface 24.

A stepped pin 26 for attaching a pressing plate is disposed on each side portion of the side end surface 23 in the length direction of the shell mounting surface 24 (on both sides in the head-tail direction). As shown in FIG. 2 (d), the stepped pin 26 includes a small-diameter leg portion 26a that is embedded and fixed vertically to the base plate 2 from the shell mounting surface 24, and a head portion 26b formed at the tip. I have. The head 26b protrudes from the shell mounting surface 24, and the head 26b is the leg 2.
It is a stepped head that is thicker than 6a and has a small-diameter head 26d with a relatively small diameter on the leg side compared to the large-diameter head 26c on the tip side.

  FIG. 3A is a partial perspective view showing the head mounting portion 22 of the base plate 2 to which the plug-in type pressing plate 4 is attached, and FIG. 3B is an explanation showing the mounting of the plug-in type pressing plate 4. FIG. 3C is a front view, a plan view, a rear view, and a cross-sectional view of the insertion-type pressing plate 4.

  Referring to FIGS. 2 and 3, the insertion-type pressing plate 4 is formed of a rectangular resin flat plate having a certain thickness. The width and length of the insertion-type pressing plate 4 are the same as those of the side end face 23 of the head mounting portion 22 of the base plate 2. Pin insertion grooves 41 are respectively formed at both ends of the insertion-type pressing plate 4 in the length direction. The interval between the pin insertion grooves 41 is the same as that of the stepped pin 26.

  As shown in FIG. 3 (c), the pin insertion groove 41 opens to the long side edge 4a on the lower side of the insertion-type pressing plate 4, and extends upward from the long side edge 4a with a certain width. The upper end portion of the groove has a semicircular shape, and is a groove having an inverted U shape as a whole.

  When the insertion-type pressing plate 4 is attached to the shell mounting surface 24 so that the stepped pin 26 of the shell mounting surface 24 is inserted into the pin insertion groove 41 of the insertion-type pressing plate 4 from below, FIG. As shown in d), a certain gap is formed between the inner surface 4b of the plug-type pressing plate 4 and the shell mounting surface 24 facing the inner surface 4b. This gap dimension corresponds to the thickness of the frame plate portion 35 of the shell frame 32.

  Further explanation with reference to FIG. 2D and FIG. 3C, the inner peripheral edge portion of the insertion-type pressing plate 4 in which the pin insertion groove 41 is formed has a constant width and an inverted U-shape. A thin inner peripheral edge portion 42 is formed. The thin inner peripheral edge portion 42 is an inverted U-shaped concave portion that is recessed by one step from the outer surface 4 c facing outward in the plug-in type pressing plate 4. This depth is the same as the thickness of the large-diameter head portion 26 c on the tip side of the head portion of the stepped pin 26.

  The opening width of the pin insertion groove 41 corresponds to the diameter of the small-diameter head portion 26d of the stepped pin 26, and functions as a guide groove for the small-diameter head portion 26d. The width of the inverted U-shaped concave portion of the thin inner peripheral edge portion 42 surrounding the pin insertion groove 41 corresponds to the diameter of the large-diameter head portion 26c of the stepped pin 26 and functions as a guide portion for the large-diameter head portion 26c.

  Further, in a state where the stepped pin 26 is inserted into the pin insertion groove 41, a gap corresponding to the thickness of the frame plate portion 35 of the shell frame 32 is provided between the insertion-type pressing plate 4 and the shell mounting surface 24. The protrusion height of the stepped pin 26 is set so that it can be done.

  In addition, as shown in FIGS. 2D, 3B, and 3C, the plug-type pressing plate 4 has gap sealing plates at both end portions in the length direction on the inner surface 4b. 43 can be pasted. The thickness of the gap sealing plate 43 is the same as the thickness of the frame plate portion 35 of the shell frame 32. Further, the interval between the pair of gap sealing plates 43 is set so that the frame plate portion 35 is located.

In the shell mounting structure thus configured, the head shell 3 is fixed to the base plate 2 as follows. First, as shown in FIGS. 2A and 2B, the frame plate portion 35 of the shell frame 32 of the head shell 3 is attached to the shell mounting surface 24 of the side end face 23 of the head mounting portion 22 of the base plate 2. Overlapping in the state of being positioned on. That is, the frame plate portion 35 is overlapped with the shell mounting surface 24 in a state where the pins 25 of the shell mounting surface 24 are inserted into the pin holes 36 of the frame plate portion 35. As a result, the frame plate portion 35 can be
4, each pin hole 36 is sealed by each pin 25.

  Next, as shown in FIGS. 2 (c) and 3 (b), the insertion-type pressing plate 4 is inserted into the stepped pins 26 located on both sides of the frame plate portion 35 of the head shell 3 from above. The pin insertion groove 41 is positioned. In this state, the insertion-type pressing plate 4 is slid downward (dropped) along the surface of the shell frame 32. The insertion-type pressing plate 4 is guided by the stepped pins 26 on both sides, and is attached to the surface of the frame plate portion 35 of the shell frame 32.

  As a result, as can be seen from the cross section shown in FIG. 1 (c), the frame plate portion 35 of the shell frame 32 is pressed against the shell mounting surface 24 of the head mounting portion 22 of the base plate 2 by the plug-in type pressing plate 4. Fixed in a fixed state. Further, on both sides of the frame plate portion 35 of the shell frame 32, the gap between the insertion-type pressing plate 4 and the shell mounting surface 24 is a gap sealing plate 43 attached to the inner surface 4 b of the insertion-type pressing plate 4. Blocked by.

  When the head shell 3 is removed from the base plate 2, the insertion-type pressing plate 4 may be slid upward until the pin insertion groove 41 is removed from the stepped pin 26. When the plug-type holding plate 4 is removed from the side end face 23, the shell frame 32 of the head shell 3 can be removed from the side end face 23 of the base plate 2.

(Another example of holding plate)
Here, as a pressing plate used for attaching the head shell 3 to the base plate 2, a slide-type pressing plate shown in FIG. 4 can be used instead of the insertion-type pressing plate 4.

  4 (a) is an explanatory view showing the head-mounted portion of the base plate to which the slide type pressing plate is attached, and FIG. 4 (b) is an explanatory view showing the mounting of the slide type pressing plate. (C) is a front view, a plan view, a rear view, and a cross-sectional view of a slide-type pressing plate.

  Also in this case, the structure other than the slide-type presser plate 400 is the same as that described above, and the pair of stepped pins 26 having the above-described configuration is attached to the shell attachment surface 24 on the base plate 2 side.

  In the slide type pressing plate 400, a pair of pin insertion holes 401 that penetrates in the thickness direction of the pressing plate 400 is formed at a position where the stepped pin 26 can be inserted. As shown in FIG. 4C, the pin insertion hole 401 is a long hole in which a large hole portion 402 is formed on one side and a small hole portion 403 is formed on the other side. The large hole portion 402 is large enough to pass the large diameter head 26c of the stepped pin 26, and the small hole portion 403 large enough to pass the small diameter head 26d of the stepped pin 26. (Refer to FIG. 2D for the stepped pin 26).

  Further, the inner peripheral edge portion of the small hole portion 403 in the slide type pressing plate 400 is a thin concave inner peripheral edge portion 404 that surrounds the small hole portion 403 with a constant width. The depth of the hole inner peripheral edge portion 404 corresponds to the thickness of the large-diameter head portion 26c of the stepped pin 26.

  The frame plate portion 35 of the shell frame 32 of the head shell 3 is superposed on the shell mounting surface 24 of the base plate 2 in a positioned state (see FIG. 2B). Next, as shown in FIG. 4B, the slide-type pressing plate 400 is positioned from the outside on the side with respect to the shell mounting surface 24 of the base plate 2. Then, the slide-type pressing plate 400 is overlaid on the surface of the frame plate portion 35 of the shell frame 32 so that the stepped pin 26 is inserted into the large hole portion 402 of the pin insertion hole 401 on both sides.

  Thereafter, the slide type pressing plate 400 is slid in a direction in which the stepped pin 26 moves relatively to the small hole portion 403 side. As a result, the slide-type pressing plate 400 is pressed against the frame plate portion 35 by the large-diameter head portion 26 c of the stepped pin 26, and the frame plate portion 35 is fixed to the shell mounting surface 24.

  Here, also in the slide-type pressing plate 400, gap sealing plates can be attached to both end portions on the inner surface thereof. Thereby, in a state where the frame plate portion 35 of the shell frame 32 is sandwiched between the shell mounting surface 24 and the slide-type pressing plate 400, the gap formed on both sides of the frame plate portion 35 can be sealed.

  5A to 5F are a plan view, a front view, a bottom view, a rear view, a left side view, and a right side view showing an example of the base plate 2 of the posture fixing shell system 1 described above. FIG. 6A is a partial perspective view showing the head mounting portion 22 in the base plate 2, FIG. 6B is a partial plan view thereof, and FIG. 6C is a partial side view thereof. is there.

DESCRIPTION OF SYMBOLS 1 Body posture fixed shell system 2 Base plate 2a Top surface 3 Head shell 4 Plug-type holding plate 4a Long side edge 4b Inner surface 4c Outer surface 21 Body part 22 Head mounting part 23 Side end surface 24 Shell mounting surface 25 Pin 26 Stepped pin 26a Leg portion 26b Head portion 26c Large diameter head portion 26d Small diameter head portion 31 Shell main body 31a Edge end portion 32 Shell frame 33 Frame plate 34 Insertion groove portion 35 Frame plate portion 36 Pin hole 41 Pin insertion groove 42 Thin wall Inner peripheral edge portion 43 Gap sealing plate 400 Slide type pressing plate 401 Pin insertion hole 402 Large hole portion 403 Small hole portion 404 Inner peripheral edge portion

Claims (5)

A shell mounting structure for attaching a body position fixing shell used to fix a patient's head, which is placed on a base plate installed on the top surface of a treatment table in particle beam therapy, to the base plate,
A shell mounting surface formed of a plane having a constant width formed on side end surfaces on both sides of the base plate;
A frame plate portion made of a rectangular flat plate having a width wider than the shell mounting surface and a constant thickness, formed on a plate-like shell frame fixed to the edge portions on both sides of the body posture fixing shell;
A positioning portion for positioning and overlapping the frame plate portion on the shell mounting surface;
A holding plate made of a rectangular flat plate having a constant width and the same width as the side end surface and longer than the frame plate portion;
An attaching portion for positioning and attaching the pressing plate in a state of sandwiching the frame plate portion between the shell attaching surface and the side end surface;
Have
The positioning portion can be inserted into the pin hole penetrating the frame plate portion in the thickness direction, and the protruding height corresponding to the thickness of the frame plate portion from the shell mounting surface. A positioning pin having a thickness,
The frame plate portion of the shell frame is overlapped with the positioning pin inserted into the pin hole and the pin hole is sealed with respect to the shell mounting surface, and the pressing plate is attached to the frame plate portion. A shell mounting structure, characterized in that the shell mounting structure is attached to the side end surface in a superimposed manner. The mounting portion is
In the shell mounting surface, a pair of mounting pins arranged at a wider interval than the length of the frame plate portion;
A pair of pin insertion grooves that are formed at positions corresponding to the pair of mounting pins at one long side edge of the pressing plate and into which the mounting pins can be inserted,
With
The mounting pin includes a leg portion embedded and fixed to the base plate from the shell mounting surface, and a stepped head formed at the tip of the leg portion and protruding from the shell mounting surface ,
When the pressing plate is slid along the shell mounting surface and the mounting pin is inserted into the pin insertion groove, the stepped head portion is a concave groove inner periphery that surrounds the pin insertion groove in the pressing plate. The frame plate portion of the shell frame is sandwiched between the pressing plate and the shell mounting surface by engaging with the portion from the outside in the thickness direction, and the outer surface of the pressing plate and the stepped portion The shell mounting structure according to claim 1, wherein a state in which a tip end surface of the head is located on the same plane is formed. The mounting portion is
In the shell mounting surface, a pair of mounting pins arranged at a wider interval than the length of the frame plate portion;
A pair of pin insertion holes penetrating the pressing plate in the thickness direction at a position corresponding to the pair of mounting pins in the pressing plate;
With
The mounting pin includes a leg portion embedded and fixed to the base plate from the shell mounting surface, and a stepped head formed at the tip of the leg portion and protruding from the shell mounting surface,
The pin insertion hole is a long hole in which a large hole part having a size capable of inserting the stepped head is formed on one side, and a small hole part is formed on the other side,
When the insertion pin is passed through the large hole portion of the pin insertion hole and the holding plate is slid in the direction in which the insertion pin relatively moves toward the small hole portion, the mounting pin The stepped head is engaged with the inner peripheral edge of the small hole portion of the pressing plate from the outside in the thickness direction, and the shell is interposed between the pressing plate and the shell mounting surface. The shell mounting structure according to claim 1, wherein the frame plate portion of the frame is sandwiched, and a state is formed in which an outer surface of the pressing plate and a tip surface of the stepped head are positioned on the same plane. A gap sealing plate having the same thickness as the frame plate portion of the shell frame is attached to both end portions in the length direction on the inner surface facing the side end surface of the pressing plate,
The gap between the pressing plate and the side end surface formed on both sides of the shell plate portion of the shell frame attached to the shell mounting surface is sealed by the gap sealing plate. Or the shell attachment structure of 3. A base plate installed on the top of the treatment table in particle beam therapy;
A posture fixing shell used to fix a patient's head placed on the base plate to the base plate so as not to move;
Have
The body position fixing shell system, wherein the body position fixing shell is attached to the base plate by the shell mounting structure according to any one of claims 1 to 4.