Patent Publication Number: US-2021178186-A1

Title: Focusing head and radiotherapy equipment

Description:
The present disclosure is a US national phase application of PCT Application No. PCT/CN2019/092802, filed on Jun. 25, 2019, which claims priority to Chinese Patent Application No. 201821046013.2, filed on Jun. 29, 2018 and entitled “FOCUSING HEAD AND RADIOTHERAPY APPARATUS,” the entire contents of each of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of medical technologies, in particular relates to a focusing head and radiotherapy equipment. 
     BACKGROUND 
     A gamma knife is large-scale medical equipment mainly used for treating craniocerebral diseases. Based on the three-dimensional geometric orientation, the gamma knife selectively determines normal tissue or diseased intracranial tissue as a target, and then focuses gamma rays generated by cobalt-60 on the target, the gamma rays irradiate the target in a large dose at one time, such that the targets are subject to focal necrosis or functional changes, thereby achieving the purpose of treating the diseases. 
     SUMMARY 
     The present disclosure provides a focusing head and radiotherapy equipment. The technical solutions are described as below. 
     In a first aspect, a focusing head is provided. The focusing head includes: 
     a cartridge configured to carry a plurality of radiation sources; 
     a shielding roller with the cartridge therein; 
     a first driving assembly connected to the cartridge and configured to drive the cartridge to rotate; and 
     a second driving assembly connected to the shielding roller and configured to drive the shielding roller to rotate. 
     Optionally, the first driving assembly includes a first driving motor, and a first driving structure connected to the cartridge, wherein the first driving motor is configured to drive the cartridge to rotate via the first driving structure. 
     The second driving assembly includes a second driving motor, and a second driving structure connected to the shielding roller, wherein the second driving motor is configured to drive the shielding roller to rotate via the second driving structure. 
     Optionally, the first driving structure includes a cartridge driving gear set. 
     The cartridge driving gear set includes a first motor driving gear connected to the first driving motor, and a cartridge driving gear connected to the cartridge. 
     Optionally, the cartridge driving gear set further includes a first intermediate gear, wherein the first intermediate gear is engaged with both the first motor driving gear and the cartridge driving gear. 
     Optionally, the second driving structure includes a roller driving gear set. 
     The roller driving gear set includes a second motor driving gear connected to the second driving motor, and a roller driving gear connected to the shielding roller. 
     Optionally, the roller driving gear set further includes a second intermediate gear, wherein the second intermediate gear is engaged with both the second motor driving gear and the roller driving gear. 
     Optionally, an outer surface of the cartridge is tangent to an inner surface of the shielding roller, and the plurality of radiation sources are disposed on the side, tangent to the shielding roller, in the cartridge. 
     Optionally, the shielding roller includes a roller body, and a plurality of ray channels disposed on a side wall of the roller body; 
     wherein the plurality of radiation sources are communicated with the plurality of ray channels in one-to-one correspondence when the focusing head is in a source-on state, and the plurality of radiation sources are staggered with the plurality of ray channels when the focusing head is in a source-off state. 
     Optionally, the first driving assembly is configured to drive the cartridge to rotate when the focusing head is switched between the source-on state and the source-off state. 
     Optionally, the second driving assembly is configured to drive the shielding roller to rotate when the focusing head is switched between the source-on state and the source-off state. 
     Optionally, when the focusing head is switched between the source-on state and the source-off state, the first driving assembly is configured to drive the cartridge to rotate in a first direction and the second driving assembly is configured to drive the shielding roller to rotate in a second direction, wherein the first direction is opposite to the second direction. 
     Optionally, the cartridge and the shielding roller rotate relative to each other at an acute angle. 
     Optionally, the first driving assembly is configured to drive the cartridge to rotate by 180°, and the second driving assembly is configured to drive the shielding roller to rotate by 90°. 
     Optionally, an external diameter of the cartridge is less than an internal diameter of the shielding roller. 
     Optionally, the cartridge is driven by the first driving assembly to rotate around a center axis of the shielding roller, and the shielding roller is driven by the second driving assembly to rotate around the center axis of the shielding roller. 
     Optionally, a distance between a center axis of the cartridge and the center axis of the shielding roller is 22 mm. 
     Optionally, the focusing head further includes a shielding layer for cladding the shielding roller. 
     Optionally, the focusing head further includes a collimator with a plurality of collimation channels thereon, wherein the plurality of ray channels are communicated with the plurality of collimation channels in one-to-one correspondence when the focusing head is in the source-on state. 
     Optionally, a material of the shielding roller includes a tungsten alloy. 
     In a second aspect, radiotherapy equipment is provided. The radiotherapy equipment includes a rotating gantry and a focusing head connected to the rotating gantry. The focusing head includes: 
     a cartridge configured to carry a plurality of radiation sources; 
     a shielding roller with the cartridge therein; 
     a first driving assembly connected to the cartridge and configured to drive the cartridge to rotate; and 
     a second driving assembly connected to the shielding roller and configured to drive the shielding roller to rotate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For clearer descriptions of the technical solutions in the embodiments of the present disclosure, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings as described below show merely some embodiments of the present disclosure, and a person of ordinary skill in the art may also derive other drawings from these accompanying drawings without creative efforts. 
         FIG. 1  is a schematic structural diagram of a focusing head in the related art; 
         FIG. 2  is a schematic diagram of the focusing head of  FIG. 1  in a source-on state; 
         FIG. 3  is a schematic diagram of the focusing head of  FIG. 1  in a source-off state; 
         FIG. 4  is a schematic diagram of the focusing head of  FIG. 1  of which the sources are quickly turned off; 
         FIG. 5  is a schematic structural diagram of a focusing head according to an embodiment of the present disclosure; 
         FIG. 6  is a side view of the focusing head shown in  FIG. 5 ; 
         FIG. 7  is a structural block diagram of a focusing head according to an embodiment of the present disclosure; 
         FIG. 8  is a schematic structural diagram of another focusing head according to an embodiment of the present disclosure; 
         FIG. 9  is a schematic structural diagram of yet another focusing head according to an embodiment of the present disclosure; 
         FIG. 10  is a schematic structural diagram of still another focusing head according to an embodiment of the present disclosure; 
         FIG. 11  is a schematic diagram of the focusing head of  FIG. 9  in a source-on state; 
         FIG. 12  is a schematic diagram of the focusing head of  FIG. 9  in a source-off state; and 
         FIG. 13  is a schematic diagram of the focusing head in  FIG. 9  after the sources are quickly turned off. 
     
    
    
     DETAILED DESCRIPTION 
     To present the object, technical solutions and advantages of the present disclosure more clearly, the embodiments of the present disclosure are described in further detail with reference to the accompanying drawings. 
     In the related art, referring to  FIG. 1 ,  FIG. 2 , and  FIG. 3 , as a main component of the gamma knife, a focusing head may include a cobalt source cartridge  01 , a tungsten roller  02 , a tungsten roller driving assembly  03 , a collimator  04 , a shield  05 , and the like. A plurality of radiation sources  011  are disposed in the cobalt source cartridge  01 . 
     The cobalt source cartridge  01  is disposed in and connected to the tungsten roller  02 , such that the cobalt source cartridge  01  and the tungsten roller  02  is capable of moving synchronously. 
     The tungsten roller driving assembly  03  includes a tungsten roller driving gear  031 , a intermediate gear  032 , a motor driving gear  033 , and a driving motor (not shown). The tungsten roller driving gear  031 , the intermediate gear  032 , and the motor driving gear  033  are sequentially engaged with one another. The tungsten roller driving gear  031  is connected to the tungsten roller  02 , and the motor driving gear  033  is connected to the driving motor. The driving motor drives the motor driving gear  033  to rotate and thereby drives the intermediate gear  032  and the tungsten roller driving gear  031  to rotate, and the tungsten roller driving gear  031  drives the tungsten roller  02  to rotate. That is, the driving motor drives the tungsten roller  02  and the cobalt source cartridge  01  in the tungsten roller  02  to rotate. 
     Generally, the focusing head may be in a source-on state or a source-off state. As shown in  FIG. 2 , when the focusing head is in a source-on state, rays emitted by the plurality of radiation sources  011  in the cobalt source cartridge  01  need to come out as beams after passing through a plurality of collimation holes  041  in the collimator  04 . 
     As shown in  FIG. 3 , when the focusing head is in a source-off state, rays emitted by the plurality of radiation sources  011  in the cobalt source cartridge  01  need to be shielded by the shield  05 . 
     When the focusing head is switched between a source-on state and a source-off state, the driving motor needs to simultaneously drive the tungsten roller and the cobalt source cartridge disposed in the tungsten roller to rotate. In this way, a driving operation load is high, leading to a longer time period required for switching the focusing head between the source-on state and the source-off state, and further resulting in a low therapeutic efficiency of the focusing head. 
     As shown in  FIG. 4 , when the focusing head needs to be quickly switched from the source-on state to the source-off state (that is, the sources of the focusing head need to be quickly turned off), the driving motor needs to drive the tungsten roller  02  and the cobalt source cartridge  01  disposed in the tungsten roller  02  to rotate at a specified angle α, such that the shield  05  disposed outside the tungsten roller  01  shields the rays emitted by the radiation sources  011 . Since the tungsten roller and the cobalt source cartridge disposed in the tungsten roller, which are required to be driven by the driving motor, are relatively heavy, it takes a long time for the driving motor to drive the tungsten roller and the cobalt source cartridge disposed in the tungsten roller to rotate to a specified angle. 
     Referring to  FIGS. 5 and 6 ,  FIG. 5  is a schematic structural diagram of a focusing head according to an embodiment of the present disclosure, and  FIG. 6  is a side view of the focusing head shown in  FIG. 5 . 
     The focusing head includes: a cartridge  10 , a shielding roller  20 , a first driving assembly  30 , and a second driving assembly  40 . 
     The cartridge  10  is configured to carry a plurality of radiation sources  11  that may be cobalt-60 radiation sources. The cartridge  10  is disposed in the shielding roller  20 . 
     The cartridge  10  is connected to the first driving assembly  30 , and the first driving assembly  30  is configured to drive the cartridge  10  to rotate. The shielding roller  20  is connected to the second driving assembly  40 , and the second driving assembly  40  is configured to drive the shielding roller  20  to rotate. 
     Compared with the traditional solution that a focusing head simultaneously drives a cobalt source cartridge and a tungsten roller to rotate by one driving assembly, the focusing head in this embodiment drives the cartridge  10  and the shielding roller  20  to rotate via the first driving assembly  30  and the second driving assembly  40  respectively. In this way, the driving operation load of each driving assembly is reduced, and thus a time period required for switching the focusing head between the source-on state and the source-off state is shortened, thereby improving the therapeutic efficiency of the focusing head. 
     Currently, international standards require that the sources of the focusing head to be quickly turned off within 0.2 seconds. In the related art, since a driving motor needs to simultaneously drive the tungsten roller and the cobalt source cartridge in the tungsten roller to rotate and the driving operation load is high accordingly, it is difficult to quickly turn off the sources of the focusing head within 0.2 seconds. In this embodiment, since the first driving assembly  30  and the second driving assembly  40  respectively drive the cartridge  10  and the shielding roller  20  to rotate, and the driving operation load of each driving assembly is low, thus the time required for quickly turning off the sources of the focusing head can be shortened. In this embodiment, it is easier to quickly turn off the sources of the focusing head within 0.2 seconds, such that the therapeutic efficiency of the focusing head is further improved. 
     In summary, according to the focusing head in this embodiment, the first driving assembly is connected to the cartridge and configured to drive the cartridge to rotate, and the second driving assembly is connected to the shielding roller and configured to drive the shielding roller to rotate. In this way, the driving operation load of each driving assembly is effectively reduced, and thus a time period required for switching the focusing head between the source-on state and the source-off state is shortened, thereby effectively improving the therapeutic efficiency of the focusing head. In addition, time required for quickly turning off the sources of the focusing head is shortened, such that the therapeutic efficiency of the focusing head is further improved. 
     Optionally, referring to  FIG. 7 , a structural block diagram of a focusing head according to an embodiment of the present disclosure is shown. The first driving assembly in the focusing head includes a first driving motor  32 , and a first driving structure  31  connected to the cartridge  10 . The first driving motor  32  is configured to drive the cartridge  10  to rotate via the first driving structure  31 . The second driving assembly in the focusing head includes a second driving motor  42 , and a second driving structure  41  connected to the shielding roller  20 . The second driving motor  42  is configured to drive the shielding roller  20  to rotate via the second driving structure  41 . 
     It should be noted that the first driving structure  32  and the second driving structure  42  may be the same or different. For example, both the first driving structure  32  and the second driving structure  42  are gear sets; or both of them are coordinated structures of gear and rack; or one of the first driving structure  32  and the second driving structure  42  is a gear set, and the other is a coordinated structure of gear and rack. The following embodiments take a case where both the first driving structure  32  and the second driving structure  42  are gear sets as an example for illustrative descriptions. 
     Illustratively, referring to  FIG. 7  and  FIG. 8 .  FIG. 8  is a schematic structural diagram of another focusing head according to an embodiment of the present disclosure. The first driving structure  31  in the first driving assembly  30  includes a cartridge driving gear set. The cartridge driving gear set includes a first motor driving gear  311  and a cartridge driving gear  313 . The first motor driving gear  311  is connected to the first driving motor  32 , and the cartridge driving gear  313  is connected to the cartridge  10 . Optionally, the cartridge driving gear set further includes a first intermediate gear  312 . The first intermediate gear  312  is engaged with both the first motor driving gear  311  and the cartridge driving gear  313 . The first driving motor  32  drives the first motor driving gear  311  to rotate, and thereof to drive the first intermediate gear  312  and the cartridge driving gear  313  to rotate, and thus the cartridge driving gear  313  drive the cartridge  10  to rotate, such that the first driving motor  32  drives the cartridge  10  to rotate. 
     The second driving structure  41  in the second driving assembly  40  includes a roller driving gear set. The roller driving gear set includes a second motor driving gear  411  and a roller driving gear  413 . The second motor driving gear  411  is connected to the second driving motor  42 , and the roller driving gear  413  is connected to the shielding roller  20 . Optionally, the roller driving gear set further includes a second intermediate gear  412 . The second intermediate gear  412  is engaged with both the second motor driving gear  411  and the roller driving gear  413 . The second driving motor  42  drives the second motor driving gear  411  to rotate and thereof to drive the second intermediate gear  412  and the roller driving gear  413  to rotate, and thus the roller driving gear  413  drives the shielding roller  20  to rotate, such that the second driving motor  42  drives the shielding roller  20  to rotate. 
     In this embodiment, referring to  FIG. 9 , a schematic structural diagram of yet another focusing head according to an embodiment of the present disclosure is shown. A plurality of radiation sources  11  are carried in the cartridge  10 , and the shielding roller  20  includes a roller body  22 , and a plurality of ray channels  21  disposed on a side wall of the roller body  22 . It should be noted that in this embodiment, an area, where the ray channels  21  are not disposed, on the roller body  22  in the shielding roller  20  is a shielding area. The focusing head further includes a collimator  50 , and a plurality of collimation channels  51  are disposed on the collimator  50 . It also should be noted that the plurality of collimation channels  51  may be divided into a plurality of collimation hole groups  52 , and the number of the collimation channels  51  in each collimation hole group  52  equals the number of the radiation sources  11  carried in the cartridge  10 . 
     In in an example embodiment, referring to  FIG. 10 ,  FIG. 10  is a schematic structural diagram of still another focusing head according to an embodiment of the present disclosure. In order to ensure that the shielding area in the shielding roller  20  shields rays emitted by the radiation sources  11 , an outer surface of the cartridge  10  needs to be tangent to an inner surface of the shielding roller  20 , and the plurality of radiation sources  11  in the cartridge  10  are disposed on the side, tangent to the shielding roller  20 , of the cartridge  10 . At this time, the rays emitted by the radiation sources  11  is directly shielded by the side, tangent to the cartridge, of the shielding roller  20 . 
     Optionally, an external diameter of the cartridge  10  is less than an internal diameter of the shielding roller  20 . The cartridge  10  is driven by the first driving assembly to rotate around a center axis of the shielding roller  20 , and the shielding roller  20  is driven by the second driving assembly to rotate around the center axis of the shielding roller  20 . That is, a rotation axis of the cartridge  10  driven to rotate by the first driving assembly is coincided with a rotation axis of the shielding roller  20  driven to rotate by the second driving assembly. At this time, a center axis of the cartridge  10  is not coincided with the rotation axis of the cartridge  10 , an offset A is present between the center axis of the cartridge  10  and the rotation axis of the cartridge  10 , wherein the offset A may be 22 mm. That is, the distance between the center axis of the cartridge  10  and the center axis of the shielding roller is 22 mm. 
     Optionally, the focusing head further includes a shielding layer  60  for cladding the shielding roller  20 . International standards require that a radiation dose measured 5 cm away from the surface of the focusing head should not be greater than 200 uSv/h (micro sievert per hour). If the radiation sources  11  are cobalt-60 radiation sources, and a material of the shielding roller  20  includes a tungsten alloy and a material of the shielding layer includes a steel-lead alloy, the total thickness of the shielding roller  20  and the shielding layer  60  may not be less than 180 mm. 
     In the embodiments of the present disclosure, the cartridge  10  is driven by the first driving assembly  30 , and/or the shielding roller  20  is driven by the second driving assembly  40 , such that the focusing head is in the source-on state or the source-off state. 
     Referring to  FIG. 11 ,  FIG. 11  is a schematic diagram of the focusing head of  FIG. 9  in a source-on state. When the plurality of radiation sources  10  are communicated with the plurality of ray channels  21  in one-to-one correspondence, and the plurality of ray channels  21  are communicated with the plurality of collimation channels  51  in one collimation hole group  52  on the collimator  50  in one-to-one correspondence, the focusing head is in the source-on state. At this time, the rays emitted by the plurality of radiation sources  11  in the cartridge  10  come out as beams after sequentially passing through the corresponding ray channels  21  in the shielding roller  20  and the corresponding collimation channels  51  in one collimation hole group  52  in the collimator  50 . 
     Referring to  FIG. 12 ,  FIG. 12  is a schematic diagram of the focusing head of  FIG. 9  in a source-off state. When the plurality of radiation sources  10  are staggered with the plurality of ray channels  21 , the focusing head is in the source-off state. At this time, the rays emitted by the plurality of radiation sources  11  in the cartridge  10  are shielded by the shielding area of the shielding roller  20 . 
     In this embodiment, the focusing head may be switched between the source-on state and the source-off state in a plurality of ways. This embodiment takes the following three ways as examples for illustrative descriptions. 
     In a first way, the first driving assembly  30  is configured to drive the cartridge  10  to rotate, such that the focusing head may be switched between the source-on state and the source-off state. At this time, the second driving assembly  40  may not work, i.e., the shielding roller  20  keeps stationary. Illustratively, the first driving assembly  30  drives the cartridge  10  to rotate, such that the focusing head is switched from the source-on state shown in  FIG. 11  to the source-off state shown in  FIG. 12  or the focusing head is switched from the source-off state shown in  FIG. 12  to the source-on state shown in  FIG. 11 . 
     In a second way, the second driving assembly  40  is configured to drive the shielding roller  20  to rotate, such that the focusing head is switched between the source-on state and the source-off state. At this time, the first driving assembly  30  may not work, i.e., the cartridge  10  keeps stationary. Illustratively, the second driving assembly  40  drives the shielding roller  20  to rotate, such that the focusing head is switched from the source-on state shown in  FIG. 11  to the source-off state shown in  FIG. 12 , or, such that the focusing head is switched from the source-off state shown in  FIG. 12  to the source-on state shown in  FIG. 11 . 
     In a third way, the first driving assembly  30  is configured to drive the cartridge  10  to rotate in a first direction, and the second driving assembly  40  is configured to drive the shielding roller  20  to rotate in a second direction, such that the focusing head is switched between the source-on state and the source-off state. The first direction is opposite to the second direction. Illustratively, the first driving assembly  30  drives the cartridge  10  to rotate and the second driving assembly  40  drives the shielding roller  20  to rotate, such that the focusing head is switched from the source-on state shown in  FIG. 11  to the source-off state shown in  FIG. 12  or the focusing head is switched from the source-off state shown in  FIG. 12  to the source-on state shown in  FIG. 11 . 
     It should be noted that in another way, the first direction and the second direction may be the same, but it is necessary to ensure that an angle at which the first driving assembly  30  drives the cartridge  10  to rotate is different from an angle at which the second driving assembly  40  drives the shielding roller  20  to rotate. 
     Illustratively, when the focusing head is switched from the source-on state to the source-off state, as shown in  FIG. 10 , the first driving assembly drives the cartridge  10  to rotate in the first direction, such that the rays emitted by the plurality of radiation sources  11  in the cartridge  10  are shielded by the shielding area in the shielding roller  20 ; and the second driving assembly drives the shielding roller  20  to rotate in the second direction, such that the plurality of ray channels  21  in the shielding roller  20  are shielded by the shielding layer  60 , thereby preventing the rays emitted by the radiation sources  11  in the cartridge  10  from passing through the plurality of ray channels  21 . In this embodiment, the angle at which the first driving assembly drives the cartridge to rotate may be different from the angle at which the second driving assembly drives the shielding roller to rotate. For example, the first driving assembly may drive the cartridge to rotate by 180 degrees, and the second driving assembly may drive the shielding roller to rotate by 90 degrees. 
     In this embodiment, since the rays emitted by the radiation sources are shielded by the shielding area of the shielding roller  20  when the focusing head is in the source-off state, the thickness of the shielding layer in the focusing head can be reduced, thereby further effectively reducing the size of the focusing head. 
     In this embodiment, when the focusing head needs to be quickly switched from the source-on state to the source-off state (i.e., the sources of the focusing head need to be quickly turned off), the sources of the focusing head may also be quickly turned off by the aforementioned three implementation modes. Normally, when the sources of the focusing head are quickly turned off, it is necessary for the focusing head to ensure that the cartridge  10  and the shielding roller  20  rotate relative to each other at an angle, usually an acute angle, within 0.2 seconds, such that the focusing head is switched from the source-on state to the source-off state. 
     In the related art, when the sources of the focusing head need to be quickly turned off, as shown in  FIG. 4 , the driving motor needs to simultaneously drive the tungsten roller  02  and the cobalt source cartridge  01  in the tungsten roller  02  to rotate by a specified angle α. The rays emitted by the radiation sources  011  in the cobalt source cartridge  01  are shielded by the shield  05  disposed at the periphery of the tungsten roller  02  and the shielding area in the collimator  04 . If the radiation sources  011  are cobalt-60 radiation sources, in order to enable the shield  05  and the shielding area in the collimator  04  to better shield the rays emitted by the radiation sources  011 , it is necessary to ensure that the total thickness of the shield  05  and the shielding area in the collimator  04  is not less than 65 mm. Therefore, the driving motor needs to drive the tungsten roller  02  to rotate at the specified angle α, which has a certain requirement, and usually, the specified angle α is relatively great. 
     In this embodiment, referring to  FIG. 13 , a schematic diagram of the focusing head in  FIG. 9  after the sources are quickly closed is shown. After the sources of the focusing head are quickly turned off under driving of the first driving assembly and/or the second driving assembly, the plurality of radiation sources  11  in the cartridge  10  are shielded by the shielding area in the shielding roller  20 . If the radiation sources  11  in the cartridge  10  are cobalt-60 radiation sources, and a material of the shielding roller  20  includes a tungsten alloy, the thickness of the shielding roller  20  needs to be 65 mm in order to enable the shielding area in the shielding roller  20  to better shield the rays emitted by the radiation sources  11 . After the sources of the focusing head are quickly turned off, the shielding area in the shielding roller  20  can directly shield the rays emitted by the radiation sources  11 . Therefore, it is only necessary to ensure that the direction in which the radiation sources  11  emit the rays is staggered with an extending direction of the corresponding ray channel in the shielding roller  20 . In this way, the direction in which each radiation source  11  emits the rays forms a relatively small specified angle β with the extending direction of the corresponding ray channel  21 . That is, when the sources of the focusing head are quickly turned off, the angle β at which the cartridge  10  and the shielding roller rotate relative to each other, which further shortens time required for quickly turning off the sources of the focusing head. 
     Moreover, since the shielding area in the shielding roller  20  may directly shield the rays emitted by the radiation sources  11 , neither the shielding layer  60  nor the shielding area on the collimator  50  needs to perform shielding, such that the collimator  50  no longer participates in the quick source-off process of the focusing head. The collimator  50  can be provided with more collimation hole groups, thereby effectively widening the treatment range of the focusing head. 
     In summary, according to the focusing head provided by this embodiment, the first driving assembly is connected to the cartridge and configured to drive the cartridge to rotate, and the second driving assembly is connected to the shielding roller and configured to drive the shielding roller to rotate. In this way, the driving operation load of each driving assembly is effectively reduced, and thus a time period required for switching the focusing head between the source-on state and the source-off state is shortened, thereby effectively improving the therapeutic efficiency of the focusing head. In addition, time required for quickly turning off the sources of the focusing head is shortened, such that the therapeutic efficiency of the focusing head is further improved. Meanwhile, since the rays emitted by the radiation sources are shielded by the shielding area of the shielding roller when the focusing head is in the source-off state, the thickness of the shielding layer in the focusing head can be reduced, making the size of the focusing head smaller. The collimator in the focusing head does not participate in the quick source-off process of the focusing head, such that the collimator can be provided with more collimation hole groups, thereby effectively widening the treatment range of the focusing head. 
     An embodiment of the present disclosure further provides a radiotherapy device. The radiotherapy device includes a rotating gantry and a focusing head connected to the rotating gantry. The focusing head may include a cartridge, a shielding roller, a first driving assembly and a second driving assembly. The cartridge is configured to carry a plurality of radiation sources and is disposed in the shielding roller. The first driving assembly is connected to the cartridge and configured to drive the cartridge to rotate. The second driving assembly is connected to the shielding roller and configured to drive the shielding roller to rotate. Illustratively, the focusing head is the focusing head shown in  FIG. 5 ,  FIG. 7 ,  FIG. 8 ,  FIG. 9  or  FIG. 10 . 
     Described above are merely example embodiments of the present disclosure, and are not intended to limit the present disclosure. Within the spirit and principles of the present disclosure, any modifications, equivalent substitutions, improvements, and the like are within the protection scope of the present disclosure.