Source: https://patents.google.com/patent/WO2000074779A1/en
Timestamp: 2019-10-14 14:52:16
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WO2000074779A1 - Stable rotatable radiation gantry - Google Patents
Stable rotatable radiation gantry Download PDF
WO2000074779A1
WO2000074779A1 PCT/SE2000/001109 SE0001109W WO0074779A1 WO 2000074779 A1 WO2000074779 A1 WO 2000074779A1 SE 0001109 W SE0001109 W SE 0001109W WO 0074779 A1 WO0074779 A1 WO 0074779A1
PCT/SE2000/001109
Peder NÄFSTADIUS
Naefstadius Peder
1999-06-09 Priority to SE9902163-6 priority Critical
1999-06-09 Priority to SE9902163A priority patent/SE9902163D0/en
2000-05-30 Application filed by Scanditronix Medical Ab, Naefstadius Peder filed Critical Scanditronix Medical Ab
2000-12-14 Publication of WO2000074779A1 publication Critical patent/WO2000074779A1/en
The present invention presents an irradiation device providing a free volume around the longitudinal axis of the body (13) around the body to be irradiated. The supporting parts of a gantry (1, 2) are situated substantially radially with respect to the longitudinal axis. The gantry comprises an inner gantry part (1) with at least two supporting locations (S) to an outer gantry portion (2). The support locations (S) are situated at each side of a treatment volume (12). A radiation head (8), mechanically attached to the inner gantry part (1) and arranged to direct radiation to the treatment volume (12) is movable around the treatment volume (12). In preferred embodiments, the parts (20, 21, 22, 23) of the gantry are formed as rings, leaving a free space along the rotational axis (9). A body-supporting couch (10) is arranged along the rotational axis extending through the hollow parts (20, 21, 22, 23). The radiation head (8) is preferably movable in a path also perpendicular to the rotation axis (9). Non-coplanar treatments are thereby possible to obtain. The arrangements are suitable for applying numerical control of the gantry movements. The invention also discloses irradiation methods suitable for such devices.
STABLE ROTATABLE RADIATION GANTRY
The present invention relates to devices and methods for irradiation and in particular to devices and methods for irradiation in more than one direction.
Radiation, in the form of electromagnetic radiation or particle radiation, is today used for many purposes, e.g. modification of properties of materials, sterilising purposes as well as medical diagnostics and treatment. The different purposes put different requirements on the methods and devices used, but there are also big similarities.
There are different ways to accomplish multi-directional radiation. For small radiation sources, a multitude of sources may be used. This may e.g. be used for Co-60 sources, which normally are limited in size and weight. For other radiation sources, which are heavier and /or larger, this solution becomes unpractical. Another approach is instead to arrange the radiation head in a movable fashion, e.g. attached to a gantry, which is allowed to move. Since radiation heads often are very heavy, in some cases up to several thousand kilograms, the gantries have typically to be build extremely stable. The easiest way to move the gantry is in such cases to use a rotating movement. Since it in most applications is desirable to have the body to be irradiated positioned horizontally, the rotation axis is typically oriented horizontally, so that the gantry is allowed to move besides and under the body.
The couches used together with this type of gantries is typically designed with a support portion, which is situated outside the area of the gantry movement, and a couch sticking into the gantry region substantially horizontally. The reason for this is that no couch supports can be placed in the path of the gantry rotation. Due to the asymmetric design, the couches are typically very sensitive for the positioning of the body on the couch. Placing a body on the couch will typically cause a displacement of up to 1 cm, and changing the location of the body on the couch may alter the displacement several millimetres. This implies that the motion of the couch can not be used during an accurate treatment of e.g. a tumour in the treatment volume.
The British patent GB 1 , 129,653 discloses a device for radiation therapy, which is movable in several directions. It discloses the possibility to rotate a gantry around a horizontal axis and at the same time displace the radiation head along a perpendicular circular arch relative to the gantry. This solution provides non-coplanar irradiation, but still performs the problems with instability in the gantry and couch. The American patent US 5,577,094 discloses another solution, where the gantry is movable along two perpendicular circular paths. This is, besides the earlier described stability problems also restricted mainly to cranial treatments, since the available space around the treatment volume substantially is restricted to one side.
A common problem with most equipment according to the state of the art is that there is a risk for collision between the radiation head and the body, to be irradiated, or couch. When changing irradiation directions, a manual inspection is normally required during movements of the radiation head and/ or gantry to ensure that the body is not jammed between the couch and the gantry. This problem makes any requested automation of the treatment difficult. There are some solutions of this problem, which are based on contact switches, which stops any movement, if any distances become too small. Normally, this is combined with using friction safety clutches, applied to the gantry movement. When using such solutions, the maximum allowed moment on the gantry is reduced, which further reduces the maximum retardation and acceleration. Furthermore, the contact switch solution has some reaction time, which put restrictions on the maximum speed of any motion.
The international patent application WO 89/08269 discloses an X-ray tomography apparatus. The apparatus is mounted for rotation around a patient within a circular frame. The apparatus can be displaced along the patient irradiating parallel sections of the body. However, facilities for non- coplanar irradiation are neither discussed nor easily provided for in this apparatus.
It is therefore a general object of the present invention to provide irradiation devices, which do not present the problems discussed above. In more detail, it is an object of the present invention to provide irradiation devices, which presents an improved stability in the gantry and couch. A further object with the present invention is to provide irradiation devices, which can provide accurate non-coplanar irradiation without involving movement of the body to be irradiated. Another object of the present invention is to provide a design of irradiation devices, which simplifies automatic control of the movements of different parts, without risk for collisions. Yet another object of the present invention is to provide irradiation devices which can provide radiation continuously over an angle considerably exceeding a full turn.
The above objects are achieved by a device and a method according to the enclosed claims. In general, the objects of the present invention are achieved by providing an irradiation device providing a free volume around the body to be irradiated, along its entire longitudinal axis. The supporting parts of a gantry of the irradiation device are situated substantially radially with respect to the free volume. The gantry comprises an inner gantry part with at least two supporting locations to an outer gantry part. The support locations are situated at each side of a treatment volume. A radiation head, mechanically attached to the gantry and arranged to direct radiation to the treatment volume is movable around the treatment volume. In preferred embodiments, parts of the inner and outer gantry parts are formed as rings, leaving a free space along the longitudinal axis of the body. A body- supporting couch is arranged along the rotational axis and through the hollow gantry parts. The radiation head is preferably movable along a path also perpendicular to the rotation axis. Non-coplanar treatments are thereby possible to obtain. The arrangements are suitable for applying numerical control of the gantry movements.
The invention, together with further objects and advantages thereof, may best be understood by referring to the following description taken together with the accompanying drawings, in which: FIG. 1 is a side view of a first embodiment of an irradiation device according to the present invention;
FIG. 2 is a sectional view of the irradiation device of fig. 1, taken along the line A-A; FIG. 3a is a perspective view of a couch to be used with an irradiation device according to the present invention;
FIG. 3b illustrates the movement region required for the couch;
FIG. 6 is a sectional view of the irradiation device of fig. 7, taken along the line B-B; FIG. 7 is a schematic drawing illustrating the irradiation directions achievable by a device according to the second embodiment of the present invention;
FIG. 8 is a side view of a third embodiment of an irradiation device according to the present invention; FIG. 9 is a sectional view of the irradiation device of fig. 8, taken along the line C-C;
FIG. 10 is a schematic drawing illustrating the irradiation directions achievable by a device according to the third embodiment of the present invention; FIG. 11 is a side view of a fourth embodiment of an irradiation device according to the present invention; and
The present invention is based on some general more or less pure geometrical considerations. The stability problems for gantries and couches according to the state of the art are based on the alignment of the gantry support and the couch. The gantry is normally placed substantially in the vicinity of the axis of rotation, which is substantially aligned with the extension of the couch. The couch is only possible to support in one end due to the interference with the gantry movements and the unstable gantry design is based on requirements not to disturb the couch more than necessary.
In fig. 1 , a side view of a first embodiment of an irradiation device according to the invention is illustrated. A radiation head 8 is mechanically supported by an inner gantry part, generally denoted by 1. The inner gantry part 1 comprises in the present embodiment a circle arc portion 3, a first ring portion 4 and a second ring portion 5. The radiation head 8 is movable along the circle arc portion 3, and arranged to direct radiation to a treatment volume 12. A body 11 is placed at a body- supporting couch, generally denoted by 10. The treatment volume 12 is thereby in the normal case a part of the body 11 , which is going to be treated by the radiation emitted from the radiation head 8. The first ring portion 4 and a second ring portion 5 are in this embodiment positioned at each side of the treatment volume 12. The ring portions 4, 5 are rotatably supported by an outer gantry part 2, comprising a first support portion 6 and a second support portion 7. Accordingly, the inner gantry part 1 is provided with two supporting locations S with respect to the outer gantry part 2. The inner gantry part 1 is by this arrangement possible to rotate around a rotation axis 9, which is substantially horizontal. In the present invention, the two supporting locations S are situated on each side of the treatment volume 12, in an axial direction, i.e. in the direction of the rotation axis 9. The treatment volume 12 is in a preferred embodiment positioned at the rotation axis 9.
The inner gantry part 1 is rotatable around the rotation axis 9, and may thus be used also to irradiate the treatment volume 12 from below, as indicated by the broken line structure 15. The radiation head 8 is movable along the circle arc portion 3 and the broken line head 16 illustrates one end position for the radiation head 8. The motion of the inner gantry part 1 and the radiation head 8 between the supporting locations S of the inner gantry part 1 always takes place outside a cylindrical volume, which is indicated by the broken line 13. No movable parts of the inner gantry part 1 will ever exist within this gantry rotational envelope 13, independent of the intended motion of the radiation head 8. The gantry rotational envelope 13 thus constitutes the free volume around the body to be treated 11. The body to be treated 1 1 and the couch 10 are both preferably enclosed within a second cylindrical volume, a body positioning volume 14. This body positioning volume 14 is totally enclosed by the gantry rotational envelope 13, preferably with a certain security margin. In such a case, there is no risk for jamming of the body 1 1 against the couch 10 or destruction of the radiation head 8 against the couch 10 at any time. This implies that the couch 10 can not have any supporting portions against e.g. floor or ceiling in the space between the supporting locations S of the inner gantry part 1.
A preferable solution of the couch-supporting problem is illustrated in fig. 2, where the irradiation device of fig. 1 is illustrated in a sectional view along the line A-A in the axial direction. The ring portions 4, 5 of the inner gantry part 1 are designed with a substantially circular shape, defining rotationally symmetric outer surfaces. These rotationally symmetric outer surfaces form the bearing locations of the inner gantry part 1. The support portions 6, 7 are in a corresponding manner designed with rotationally symmetric inner surfaces. The support portions 6, 7 are adapted to fit the ring portions 4, 5, leaving appropriate space for bearings, in the form of e.g. roller bearings. Since the ring portions 4, 5 and the support portions 6, 7 are formed without any parts along the rotation axis 9, there is free space available. The couch may thus extend through the ring portions 4, 5 and the support portions 6, 7, along the rotation axis 9. The couch 10 may therefore be supported by the outer gantry part 2 or, as shown in the figure, by separate supports outside the inner gantry part bearing locations. In this embodiment, the couch support is movable in height and horizontally, perpendicular to the rotation axis 9. This two-dimensional mobility is accomplished by means in the couch supports. In fig. 2, a slot portion 20 allowing for horizontal movement, and a piston 18 and cylinder 19 for vertical movement are shown. The couch 10 and its supports are described more in detail below.
Fig. 3a illustrates a perspective view of a preferred embodiment of a couch 10 according to the present invention. The couch comprises a first couch support portion 21 and a second couch support portion 22. As discussed above, the couch support portions 21, 22 may be integrated in the gantry support or provided as separate means. From the first couch support section 21, a first rigid couch portion 23 extends towards the treatment volume. From the second couch support portion 22, a second rigid couch section 24 extends towards the treatment volume, in the opposite direction. The front parts of the rigid couch sections 23, 24 are placed apart from each other and thereby form an empty volume 29 there between. This empty volume 29, at operation of the irradiation device, is situated just beneath the treatment volume 12 (see fig. 1). The rigid sections 23, 24 are preferably interconnected by a thin foil 25 of material with a low radiation cross section, e.g. polyethylene. The foil 25 is in this embodiment provided as an endless belt, which is driven by two rolls, 26, 27, and may thus serve for changing the position of the body along the rotation axis. Alternatively, rigid plates of e.g. carbon fibre may be used instead of the thin foil.
The rigid sections 23, 24 are in a preferred embodiment movable relative the gantry. Preferably, the displacements are possible in at least two translation directions, vertically, and horizontally and perpendicular to the rotation axis 9, respectively. According to fig. 3a, these directions are denoted z and y, respectively. The y- motion of the rigid sections 23, 24 is in the present embodiment accomplished by letting a protrusion 28 of the rigid sections 23, 24 slide in a slot portion 20. Any conventional means for causing and controlling this motion may be used. The z-motion of the rigid sections 23, 24 is in the present embodiment accomplished by a piston 18 of the couch support portions 21, 22 which can be moved up and down in a cylinder 19. In a preferred embodiment, the motion of the rigid sections 23, 24 are independent of each other, which provides for various positioning possibilities for the body. As indicated above, the foil 25 may be used for changing the position of a body on the couch 10 in the x-direction, by driving the endless belt by the two rolls 26 and 27.
Fig. 3b illustrates a cross section of a body to be irradiated. The motion possibilities of the couch should be such that all parts of the body would be possible to position at the treatment volume. The limit movements in the z and y directions should therefore enclose the body volume, or at least the parts of the body volume, which may be a target for irradiation.
Now referring again to fig. 1 and fig. 2, the co-operation between the couch and the gantry in easily understood. The inner gantry part 1 is rotatably supported by the outer gantry part 2. The couch 10 extends from both ends along the rotation axis 9, leaving the open space 24 beneath the treatment volume 12. The couch support portions 21, 22 are provided outside the inner gantry part support locations S. When the inner gantry part 1 is rotated around the couch 10, the treatment volume 12 is available from all directions without any radiation disturbing material, except for the thin stretched foil 25.
It is easily seen in fig. 1 and 2, that the gantry is supported mainly in the radial direction, with respect of the rotation axis 9. The circular design of the ring portions 4, 5 and the support portions 6, 7 enables the clearance of the volume around the couch 10. It is also seen that since the centre of mass of the inner gantry part 1 always is situated between the support locations S, there are relatively low bending moment present in the gantry.
In a preferred embodiment, the inner gantry part 1 is continuously rotatable, relative the outer gantry part 2. The mechanical operation and support is easily provided with e.g. conventional gear solutions and bearings. One limiting factor in equipment existing today is the wiring for the radiation head. However, by introducing sliding contacts between the inner gantry part 1 and the outer gantry part 2, preferably in connection with the mechanical bearing, a true continuous rotational motion may be achieved.
Returning to fig. 1 , the radiation head 8 is movable along a circle arc portion 3 of the inner gantry part 1. The circle arc portion 3 has a centre of curvature, which is situated within the treatment volume 12, and preferably on the rotation axis 9. When the radiation head 8 is moved along the circle arc portion 3, it maintains the radiation direction towards the treatment volume 12. By combining the rotation around the horizontal axis 9 and the motion along the circle arc portion 3, a multitude of irradiation directions may be reached. During such movements, the radiation head 8 is situated at the same distance from the treatment volume 12.
The treatment situation is schematically illustrated in fig. 4. The radiation head 8 is possible to move anywhere along a spherical surface, which is cut by two parallel vertical planes 30, 31, perpendicular to the rotation axis 9. All directions within an angle Nl from a centre vertical plane 32 are achievable. A non-coplanar treatment may be achieved. Other angles than perpendicular to the rotation axis may be of interest to use in order to avoid damage of vital organs situated in the vicinity of the treatment volume 12. If the radiation head 8 is fixed at a certain position along the circle arc portion 3 and the inner gantry portion 1 is rotated, the irradiation of the treatment volume 12 will be applied in a conical shape. If the displacement the radiation head 8 is controlled simultaneously as the inner gantry part 1 moves, any other geometrical irradiation pattern may be accomplished. In this way an irradiation path on the treatment volume may be adapted to each individual case, depending on the nature of the target and the sensitivity for radiation damage in the surroundings of the treatment volume 12.
The above treatments are preferably performed in an automated manner. Since the irradiation devices according to the present invention almost totally removes the risks for mechanical jamming or contact destruction, the operational processes may be automated easily. The possibility to spread the radiation dose over a larger volume around the treatment volume is used more efficiently, if short exposures from a multitude of directions are given. This requires a rapid movement of the radiation head, which is facilitated by the stable gantry construction according to the present invention.
Furthermore, since the gantry construction according to the present invention reduces the risk for jamming considerably, other approaches of control may be implemented.
The motion of the radiation head in the two perpendicular directions may preferably be performed utilising numerical control procedures. In such a system, the coordinates of the radiation head may easily be controlled together with e.g. radiation intensity, radiation distribution etc. in order to tailoring a radiation treatment. Revolution times of the inner gantry part of the order of 5 s would be possible, enabling the radiation head to move between two arbitrary selected positions in times of the same order of magnitude. The motion of the couch may also be controlled automatically. However, there is a general request not to move the body during treatment, so the main purposes for automatic control of the couch movement is to facilitate the introduction of the body into the area of the treatment volume.
In fig. 5, a side view of a second embodiment of an irradiation device according to the invention is illustrated. In fig. 6 the irradiation device of fig. 5 is illustrated in a sectional view along the line B-B in the axial direction. A radiation head 8 is mechanically supported by an inner gantry part, generally denoted by 1. The inner gantry part 1 comprises in the present embodiment a head supporting arm 213, a ring portion 201 and a counterweight 206. The radiation head 8 is fixed at the head supporting arm 213, and arranged to direct radiation to a treatment volume 12. A body 11 is placed at a body-supporting couch, generally denoted by 10. The treatment volume 12 is thereby in the normal case a part of the body 1 1, which is going to be treated by the radiation emitted from the radiation head 8. The head supporting arm 213 is movable along the ring portion 201, which means that the radiation head is able to rotate around a rotation axis 9, which is substantially horizontal. The treatment volume 12 is in a preferred embodiment positioned at the rotation axis 9.
The inner gantry part 1 is supported, via a first rotational support 204 and a second rotational support 205, by an outer gantry part 2. The outer gantry part 2 comprises in this embodiment a generally C-shaped jaw portion 207, and a support portion 209. The jaw portion 207 surrounds the treatment volume 12 and is rotationally attached in its back end to the support portion by a rotational connection 208. The first rotational support 204 and the second rotational support 205 are attached to the front ends 202 and 203, respectively, of the jaw portion 207, and are therefore positioned at each side of the treatment volume 12, in the vertical direction. Accordingly, the inner gantry part 1 is provided with two supporting locations S with respect to the outer gantry part 2. The supporting locations S are situated on each side of the treatment volume 12, in a radial direction. The radiation head 8 is rotatable around the rotation axis 9, and may thus be used also to irradiate the treatment volume 12 from below. In order to reach non-coplanar irradiation directions, the inner gantry part 1 is rotated, either around a vertical axis 210 by the first and second rotational supports
204, 205, or around a horizontal axis 211 by the rotational connection 208. A slight rotation of the inner gantry part 1 will put the ring portion 201 as indicated by the broken line ring 212. Such a tilting will thus limit the free space around the couch 10 and body 11, and a restriction of this tilting is necessary to ensure a free space around the body. The first and second rotational supports 204, 205 are situated in the same plane as the radiation head 8, while the ring portion 201 is slightly offset, as clearly seen in fig. 5. The axes of the tilting of the inner gantry part 1, either the vertical axis 210 or the horizontal axis 211, are intersecting the treatment volume 12. This means that the radiation head 8 always is directed substantially towards the treatment volume 12.
The tilting of the inner gantry part 1 and the radiation head 8 is restricted in such a manner that all parts of the gantry and radiation head 8 are located outside a cylindrical volume, which is indicated by the broken line 13. No movable parts of the inner gantry part 1 will ever exist within this gantry rotational envelope 13, independent of the intended motion of the radiation head 8 or tilting of the inner gantry part 1. The gantry rotational envelope 13 thus constitutes the free volume around the body to be treated 1 1. The body to be treated 1 1 and the couch 10 are as in previous embodiment both preferably enclosed within a second cylindrical volume, a body positioning volume 14. This body positioning volume 14 is totally enclosed by the gantry rotational envelope 13, preferably with a certain security margin. In such a case, there is no risk for jamming of the body 11 against the couch 10 or destruction of the radiation head 8 against the couch 10 at any time.
The treatment situation in a device according to the second embodiment of the present invention is schematically illustrated in fig. 7. The radiation head 8 is possible to move anywhere along a spherical surface, which is restricted by an angle N2 from the vertical axis and an angle N3 from the axis 21 1. All directions within these angles are achievable. A non-coplanar treatment may thus be achieved. Other angles than perpendicular to the rotation axis may be of interest to use in order to avoid damage of vital organs situated in the vicinity of the treatment volume 12. If the inner gantry part 1 is fixed at a certain position with respect to the outer gantry part 2, the rotational connection 208 is at a fixed angle and the radiation head 8 is rotated, the irradiation of the treatment volume 12 will be applied in a plane 33 defined by the axis 210. If the tilting of the gantry is controlled simultaneously as the radiation head 8 rotates, any other geometrical irradiation pattern may be accomplished. In this way an irradiation path on the treatment volume 12 may be adapted to each individual case, depending on the nature of the target and the sensitivity for radiation damage in the surroundings of the treatment volume 12.
It is easily seen in fig. 5 and 6, that the gantry is supported mainly in the radial direction, with respect of the longitudinal axis of the couch, and the rotation axis 9. The circular design of the ring portion 201 enables the clearance of the volume around the couch 10.
In fig. 8, a side view of a third embodiment of an irradiation device according to the invention is illustrated. In fig. 9 the irradiation device of fig. 8 is illustrated in a sectional view along the line C-C in the axial direction. A radiation head 8 is mechanically supported by an inner gantry part, generally denoted by 1. The inner gantry part 1 comprises in the present embodiment a ring portion 301. The radiation head 8 is arranged to direct radiation to a treatment volume 12. A body 1 1 is placed at a body- supporting couch, generally denoted by 10. The treatment volume 12 is thereby in the normal case a part of the body 1 1 , which is going to be treated by the radiation emitted from the radiation head 8. The radiation head 8 is movable along the ring portion 301, which means that the radiation head 8 is able to rotate around a rotation axis 9, which is substantially horizontal. The treatment volume 12 is in a preferred embodiment positioned at the rotation axis 9.
The radiation head 8 is rotatable around the rotation axis 9, and may thus be used also to irradiate the treatment volume 12 from below. In order to reach non-coplanar irradiation directions, the inner gantry part 1 is rotated, either around a horizontal axis 310 by the first and second rotational supports 304, 305, or around a vertical axis 311 by the rotational connection 308. A slight rotation of the inner gantry part 1 will put the ring portion 301 as indicated by the broken line ring 312. Such a tilting will thus limit the free space around the couch 10 and body 11 , and a restriction of this tilting is necessary to ensure a free space around the body. The first and second rotational supports 304, 305 are situated in the same plane as the radiation head 8 and the ring portion 301. The axes of the tilting of the inner gantry part 1, either the vertical axis 311 or the horizontal axis 310, are intersecting the treatment volume 12. This means that the radiation head 8 always is directed substantially towards the treatment volume 12.
The tilting of the inner gantry part 1 and the radiation head 8 is restricted in such a manner that all parts of the gantry and radiation head 8 are located outside a cylindrical volume, which is indicated by the broken line 13. No movable parts of the inner gantry part 1 will ever exist within this gantry rotational envelope 13, independent of the intended motion of the radiation head 8 or tilting of the inner gantry part 1. The gantry rotational envelope 13 thus constitutes the free volume around the body to be treated 1 1. The body to be treated 1 1 and the couch 10 are as in previous embodiments both preferably enclosed within a second cylindrical volume, a body positioning volume 14. This body positioning volume 14 is totally enclosed by the gantry rotational envelope 13, preferably with a certain security margin. In such a case, there is no risk for jamming of the body 11 against the couch 10 or destruction of the radiation head 8 against the couch 10 at any time. The ring portion 301 of the inner gantry part 1 is designed with a substantially circular shape. This means that the ring portion 301 is formed without any parts along the rotation axis 9, where free space is available. The couch 10 may thus extend through the ring portion 301, substantially along the rotation axis 9. When the ring portion 301 is tilted in any direction, the rotation axis 9 of the radiation head 8 is also tilted. However, since the tilting is restricted to relatively small angles, the angular deviation between the longitudinal axis of the couch and body, and the rotation axis, is also relatively small.
In fig. 8, it may be noticed, that the radiation head 8 and the ring portion 201 are situated essentially in the same plane as the treatment volume 12. This means that the access to the treatment volume by visual or mechanical means is restricted. However, the design of the inner gantry part 1 is simplified as compared with the second embodiment, described above. In order to achieve access to the treatment volume, a similar design as in the previous embodiment may be provided, including weight balancing equipment.
The treatment situation in a device according to the second embodiment of the present invention is schematically illustrated in fig. 10. The radiation head 8 is possible to move anywhere along a spherical surface, which is restricted by an angle V5 from the vertical axis 311 and an angle N5 from a horizontal axis perpendicular to the longitudinal axis of the couch and body.
All directions within these angles are achievable. A non-coplanar treatment may thus be achieved. Other angles than perpendicular to the rotation axis may be of interest to use in order to avoid damage of vital organs situated in the vicinity of the treatment volume 12. If the inner gantry part 1 is fixed at a certain position with respect to the outer gantry part 2, the rotational connection 308 is at a fixed angle and the radiation head 8 is rotated, the irradiation of the treatment volume 12 will be applied in a plane 34 defined by the axis 310. If the tilting of the gantry is controlled simultaneously as the radiation head 8 rotates, any other geometrical irradiation pattern may be accomplished. In this way an irradiation path on the treatment volume 12 may be adapted to each individual case, depending on the nature of the target and the sensitivity for radiation damage in the surroundings of the treatment volume 12.
It is easily seen in fig. 8 and 9, that the gantry is supported mainly in the radial direction, with respect to the longitudinal axis of the couch, and the rotation axis 9. The circular design of the ring portion 301 enables the clearance of the volume around the couch 10. It is also seen that since the centre of mass of the inner gantry part 1 always is situated between the support locations S, there are relatively low bending moment present in the gantry.
In fig. 1 1, a fourth embodiment of an irradiation device according to the invention is illustrated. It is very similar to the first embodiment and corresponding parts having the same reference numbers will not be described or discussed again.
This fourth embodiment comprises a linear beam portion 17 interconnecting the first ring portion 4 and the second ring portion 5. The radiation head 8 is movable along the linear beam portion 17. In order to maintain the irradiation directed towards the treatment volume 12, the radiation head 8 is also allowed to be tilted with respect to the linear beam portion 17. This means that the relative angle between the linear beam portion 17 and the radiation head 8 is different in e.g. positions 15 and 16. In order to direct the radiation to the treatment volume 12, the direction of the radiation head 8 has to follow:
a = tan" (-) where is the angle from the pure radial direction, d is the displacement of the radiation head 8, and r is the distance from the tilting axis of the radiation head to the rotation axis 9.
Furthermore, the radiation head 8 changes its distance to the treatment volume 12 when it moves along the linear beam portion 17. The distance varies as
where s is the distance between the tilting axis of the radiation head 8 and the treatment volume. In most applications, it is advantageous if the isocenter distance is constant independent of the irradiation direction. However, one can compensate for the changing isocenter distance in this embodiment, by adapting collimator settings and dose according to e.g. the depth dose curve. Such adaptations may e.g. be included in the dose planning system.
However, the reduced complexity in the radiation head translation also leads to an increased complexity in that the radiation head 8 has to be tilted in a controlled manner depending on the translation position. However, means for tilting the radiation head 8 can be made rather simple, since the weight of the radiation head 8 can be supported by separate means, e.g. by an axle, around which the radiation head 8 is tilted. The controlled tilting may e.g. be obtained by mechanical and/ or electrical means according to conventionally available techniques.
Fig. 12 illustrates the embodiment of fig. 1 1 in an alternative operational mode. In this case an extended treatment volume 12 is demanded. The radiation head 8 can in such cases be moved along the linear beam portion 17 without tilting and without any focusing adjustment, e.g. to the positions 40. A series of coplanar irradiation are thus achieved, or alternatively, if the translation is continuous, a treatment along a helical path. Other variants of controlling the tilting and focusing are, of course, also possible. The embodiment of Fig. 1 1 and 12 may be advantageous for certain types of treatments, otherwise the embodiment of Fig. 1 is probably to prefer.
1. Irradiation device, comprising a gantry (1-2); a radiation head (8), mechanically supported by said gantry (1-2) and rotatable around a rotation axis (9); said radiation head (8) is arranged to direct radiation to a treatment volume (12) situated substantially on said rotation axis (9); and wherein all movable parts of said gantry (1-2) are, in all situations, situated at a distance from said rotation axis (9) which is larger than a predetermined value, characterised in that said gantry (1-2) comprises an inner gantry part (1) and an outer gantry part (2), said inner gantry part (1) is rotatably supported by said outer gantry part (2) at two support locations (S), situated at opposite sides of said treatment volume (12).
2. Irradiation device according to claim 1, characterised in that said gantry (1-2) is arranged substantially radially with respect of said treatment volume (12), as defined by said rotation axis (9).
3. Irradiation device according to claim 1 or 2, characterised in that said radiation head (8) is continuously rotatable around said rotation axis (9).
4. Irradiation device according to claim 1, 2 or 3, characterised in that said radiation head (8) is movable along at least one arc of a circle, substantially centred at said treatment volume (12), said arc being non-parallel with said rotation of said radiation head (8) around said rotation axis (9), whereby non- coplanar irradiation treatment is acheivable.
5. Irradiation device according to any of the claims 1 to 4, characterised in that said inner gantry part (1) comprises a substantially circularly shaped portion (4, 5; 201; 301) arranged around said rotation axis (9).
6. Irradiation device according to any of the claims 1 to 5, characterised in that said support locations (S) are situated on opposite sides of said treatment volume (12), in the direction of said rotation axis (9).
7. Irradiation device according to claim 6, characterised in that said inner gantry part (1) comprises a first ring portion (4) and a second ring portion (5) separated in the direction of the rotation axis (9), said ring portions (4, 5) are carried in a first support portion (6) and a second support portion (7) of said outer gantry part (2), respectively.
8. Irradiation device according to claim 7, characterised in that at least one of said pairs of said ring portions (4, 5) and said support portion (6, 7) comprises electrical connections with sliding contacts.
9. Irradiation device according to claim 7 or 8, characterised in that said inner gantry part (1) further comprises an circle arc portion (3), on which said radiation head (8) is movably supported, whereby the centre of curvature of said arc portion (3) is situated in said treatment volume (12).
10. Irradiation device according to claim 7 or 8, characterised in that said inner gantry part (1) further comprises a linear beam portion (17), on which said radiation head (8) is movably supported.
1 1. Irradiation device according to claim 10, characterised in that said radiation head (8) is tiltably supported by said linear beam portion (17), said radiation head (8) directing its radiation towards said treatment volume (12) from any position relative to said linear beam portion (17).
12. Irradiation device according to any of the claims 1 to 5, characterised in that said support locations (S) are situated on opposite sides of said treatment volume (12), perpendicular to the direction of said rotation axis (9), and provide a tilting around a first tilting axis (210; 310) through said support locations (S) and said treatment volume (12), whereby non-coplanar irradiation treatment is acheivable.
13. Irradiation device according to claim 12, characterised in that said outer gantry part (2) comprises a rotational connection (208; 308), enabling a tilting of said inner gantry part (1) around a second tilting axis (211; 311) substantially perpendicular to the first tilting axis (210; 310); said second tilting axis (21 1; 31 1) goes substantially through said treatment volume (12).
14. Irradiation device according to claim 12 or 13, characterised by electrical connections with sliding contacts between said radiation head (8) and said inner gantry part (1).
15. Irradiation device according to any of the preceding claims, characterised by means for numerical control of movable parts in said irradiation device.
16. Irradiation device according to any of the preceding claims, characterised in that said irradiation device further comprises a body supporting couch (10), comprising two couch support portions (20, 21), situated on each side of said treatment volume (12), in the direction of said rotation axis (9).
17. Irradiation device according to claim 16, characterised in that said body supporting couch (10) is formed in two rigid parts (22, 23), each one attached to one respective of said couch support portions (20, 21), said rigid parts (22, 23) are interconnected by material (24) with a low radiation cross section.
18. Irradiation device according to claim 17, characterised in that said couch support portions (20, 21) are movable independently of each other.
19. Irradiation device according to claim 18, characterised in that said couch support portions (20, 21) are movable in two translational directions, substantially perpendicular to said rotation axis (9) .
20. Irradiation device according to any of the claims 16 to 19, characterised in that said body- supporting couch (10) is arranged within a distance of said predetermined value from said rotation axis (9).
PCT/SE2000/001109 1999-06-09 2000-05-30 Stable rotatable radiation gantry WO2000074779A1 (en)
SE9902163-6 1999-06-09
SE9902163A SE9902163D0 (en) 1999-06-09 1999-06-09 Stable Rotable radiation gantry
EP00939221A EP1218062A1 (en) 1999-06-09 2000-05-30 Stable rotatable radiation gantry
AU54344/00A AU5434400A (en) 1999-06-09 2000-05-30 Stable rotatable radiation gantry
US10/009,262 US6969194B1 (en) 1999-06-09 2000-05-30 Stable rotatable radiation gantry
WO2000074779A1 true WO2000074779A1 (en) 2000-12-14
ID=20415995
PCT/SE2000/001109 WO2000074779A1 (en) 1999-06-09 2000-05-30 Stable rotatable radiation gantry
US (1) US6969194B1 (en)
EP (1) EP1218062A1 (en)
CN (1) CN1433333A (en)
AU (1) AU5434400A (en)
SE (1) SE9902163D0 (en)
WO (1) WO2000074779A1 (en)
WO2012010215A1 (en) * 2010-07-23 2012-01-26 Brainlab Ag Non-planar treatment beam control
ITUD20120161A1 (en) * 2012-09-20 2014-03-21 Asa S R L Equipment to emit therapeutic radiation
CN104221093A (en) * 2012-03-29 2014-12-17 三菱电机株式会社 Rotating gantry and particle beam therapy device
EP3281674A1 (en) * 2016-08-09 2018-02-14 Paul Scherrer Institut Particle therapy system having an additional degree of freedom on the synthesis of the angle of treatment
CN102163046B (en) * 2011-03-01 2012-11-21 深圳市一体医疗科技股份有限公司 Movement control method and system of gamma ray radiation unit
DE102012211330A1 (en) * 2012-06-29 2014-01-02 Siemens Aktiengesellschaft Intra-operative imaging device
JP6238611B2 (en) * 2012-09-28 2017-11-29 キヤノン株式会社 Mobile radiography apparatus, radiography system, and control method
GB2519592A (en) 2013-10-28 2015-04-29 Elekta Ab Radiotherapy apparatus
CN104523334B (en) * 2014-12-09 2017-03-15 湖北锐世数字医学影像科技有限公司 A multi-imaging system, auxiliary support multi-point system and control method
CN105288867B (en) * 2015-10-21 2018-01-12 江苏海明医疗器械有限公司 A radiation therapy simulator accurately control the rotational movement mechanism
CN108578905A (en) * 2018-01-26 2018-09-28 合肥驼峰电子科技发展有限公司 Annular irradiation head for millimeter wave therapeutic instrument
DE3010819A1 (en) * 1980-03-20 1981-09-24 Siemens Ag Roentgenschichtgeraet for production of transversalschichtbildern
1999-06-09 SE SE9902163A patent/SE9902163D0/en unknown
2000-05-30 WO PCT/SE2000/001109 patent/WO2000074779A1/en not_active Application Discontinuation
2000-05-30 US US10/009,262 patent/US6969194B1/en active Active
2000-05-30 AU AU54344/00A patent/AU5434400A/en not_active Abandoned
2000-05-30 EP EP00939221A patent/EP1218062A1/en not_active Withdrawn
2000-05-30 CN CN00811527A patent/CN1433333A/en not_active Application Discontinuation
CN104221093B (en) * 2012-03-29 2017-05-10 三菱电机株式会社 The rotating gantry and the particle beam therapy system
WO2014045095A3 (en) * 2012-09-20 2014-05-15 Asa Srl Apparatus to emit therapeutic radiations
WO2018028863A1 (en) * 2016-08-09 2018-02-15 Paul Scherrer Institut A gantry for particle therapy as an arm rotating in the longitudinal plane
AU5434400A (en) 2000-12-28
US6969194B1 (en) 2005-11-29
EP1218062A1 (en) 2002-07-03
SE9902163D0 (en) 1999-06-09
CN1433333A (en) 2003-07-30
KR20120107939A (en) 2012-10-04 Compact gantry for particle therapy
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