Abstract:
A system for identifying users and controlling access to a radiotherapy apparatus, comprising: a portable identification device, comprising a memory for storing identification information corresponding to a user of the device and an antenna; and a control mechanism for a radiotherapy apparatus, comprising: a wireless transceiver for communicating with the portable identification device and identifying the user of the portable identification device; and a display for displaying a user interface and receiving inputs for controlling the radiotherapy apparatus on the basis of the identified user when the portable identification device is placed on the display.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to radiotherapy, and particularly to methods, apparatus and systems for controlling access to a radiotherapy system. 
       BACKGROUND 
       [0002]    Radiotherapy involves the production of a beam of high-energy ionising radiation, usually x-rays or a beam of electrons or other sub-atomic particles. This is directed towards a target region of the patient, and adversely affects the target cells (typically tumour cells) causing an alleviation of the patient&#39;s symptoms. 
         [0003]    In order to ensure that the radiation is delivered to the patient safely, radiotherapy treatment is necessarily a complex process involving many steps. As part of that process, a number of different personnel may have cause to use the machine for different reasons, but not all will generally need access to the same machine parameters. For example, a radiotherapy technician may need to control the system directly to deliver a particular plan of treatment, whereas a nurse may need only to access the system to position a patient on the patient support. Similarly, a repair and maintenance technician may need to access parameters which are generally not available to others. It would therefore be useful to gain a measure of control over who can issue commands to the radiotherapy system, and ensure that each command has been issued by a person of appropriate qualifications. 
         [0004]    It would also be advantageous to design a medical environment with minimal exposed keys and protruding surfaces. Various fluids may be involved in the treatment process, which could get caught on levers and pulleys, or may be spilt accidentally. A system which can withstand such accidents will in general be able to maintain an operative state for a longer period of time. 
       SUMMARY OF INVENTION 
       [0005]    According to a first aspect of the present invention, there is provided a system for identifying users and controlling access to a radiotherapy apparatus, comprising: a portable identification device, comprising a memory for storing identification information corresponding to a user of the device and an antenna; and a control mechanism for a radiotherapy apparatus, comprising: a wireless transceiver for communicating with the portable identification device and identifying the user of the portable identification device; and a display for displaying a user interface and receiving inputs for controlling the radiotherapy apparatus on the basis of the identified user when the portable identification device is placed on the display. 
         [0006]    According to a second aspect of the invention, there is provided a patient support, comprising: a bed; one or more mechanisms for manipulating at least one of the position and orientation of the bed; and a display provided on an edge of the bed for displaying a user interface and receiving inputs for controlling at least the one or more mechanisms. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the following drawings, in which: 
           [0008]      FIG. 1  shows a radiotherapy system comprising a control mechanism according to embodiments of the present invention; 
           [0009]      FIG. 2  shows a partial view of a patient support according to embodiments of the present invention; 
           [0010]      FIGS. 3   a  and  3   b  are cross-section views showing operation of the control mechanism according to embodiments of the present invention; 
           [0011]      FIG. 4  is a plan view showing further detail of the control mechanism according to embodiments of the present invention; 
           [0012]      FIG. 5  shows part of a graphical user interface according to embodiments of the present invention; and 
           [0013]      FIG. 6  shows a control device according to further embodiments of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    To address the concerns noted above, a new device or “key” is provided to each radiotherapy professional. In some embodiments, the device may be used as a control device, to input commands to various devices and equipment in the therapy suite, for example by cooperating with one or more control screens. The device may contain a wireless beacon so that it can be located precisely within the suite, and contain identity data corresponding to the user of the device, so that only those controls suitable for the professional concerned are available. 
         [0015]      FIG. 1  is a schematic drawing showing a side view of a radiotherapy system  10  according to embodiments of the present invention. Treatment components of the system  10  (i.e. those which deliver the therapeutic radiation) are shown on the left-hand side of the drawing, while control components of the system  10  (i.e. those which control the treatment components) are shown on the right-hand side. This arrangement reflects the provision of a therapy machine in one room and a control mechanism for the machine in another, adjacent room. The two rooms may be linked by a window allowing a technician to view the treatment as it is carried out. In some embodiments, however, some or all of the controls may be provided in the treatment room, i.e., the controls could be split between treatment and control rooms, or there may be no separate control room. 
         [0016]    The system  10  comprises a rotatable gantry  12  which is able to rotate about an axis I. Mounted on the gantry  12  is a radiation head  14 , which provides a beam of radiation  16  directed generally towards and intersecting the axis I. In this way, a target placed at the point of intersection between the axis I and the beam  16  (commonly referred to as the isocentre) can be made to lie within the beam&#39;s extent at all angles of rotation of the gantry  12 . Radiation dose therefore builds to a relatively high level there while remaining relatively low in the surrounding volume, which lies within the beam&#39;s extent only at certain angles of rotation. 
         [0017]    The radiation head  14  may comprise, or be connected to one or more sources of therapeutic radiation (not illustrated), such as a linear accelerator or a radioactive isotope (e.g. cobalt  60 ). The beam  16  can be formed from any suitable ionizing radiation, such as protons, electrons or x-rays. 
         [0018]    The radiation head  14  may comprise one or more collimators (not illustrated) for collimating and shaping the beam  16 . The radiation head  14  may comprise one or more primary collimators which collimate the beam to take a regular geometric shape (e.g. cone beams, fan beams etc), and one or more secondary collimators to act dynamically on the regular-shaped beam so that it can have different cross-sections at different angles of rotation. That is, in general the target will not have the same profile at all angles of rotation, and the beam can be adapted to conform to that profile or take some other desirable shape as required. Multi-leaf collimators are well known secondary collimators for performing this task. 
         [0019]    An imaging panel  18  is also mounted to the gantry  12 , in a position generally opposite to that of the radiation head  14 . The panel  18  is positioned so as to intersect the radiation beam  16  after it has passed through the target, and can therefore provide information on the treatment as it is progressing. For example, the panel  18  can provide images of the radiation beam  16  (so-called “portal images”) which can be used to check the shape of the beam  16  and its position relative to anatomical structures within the patient (i.e. ensuring that the beam has an expected shape and is correctly positioned with respect to the target). The imaging data acquired by the panel  18  can also be used to build three-dimensional images of the target using CT techniques. 
         [0020]    Referring now to  FIG. 2  as well as  FIG. 1 , a patient support  20  is provided to ensure the patient is supported and comfortable throughout treatment, but also to ensure the patient is positioned correctly so that the radiation beam  16  is accurately directed towards the target. For example, the support  20  may be able to position the patient in up to six degrees of freedom: x, y, z, pitch, yaw and roll. In the illustrated embodiment, the support  20  comprises a base  22 , a support mechanism  24  and a bed  26 . The base  22  is in connection with the ground, and may be able to move in one or two dimensions so as to vary the position of the support  20  relative to the gantry  12 . The support mechanism  24  connects the bed  26  to the base  22 , and may be able to vary one or more of the height, pitch, yaw and roll of the bed  26  with respect to the base  22 . 
         [0021]    The bed  26  is primarily for supporting the patient and comprises a substantially flat rectangular surface for that purpose. One or more cushions may also be provided for comfort. In the illustrated embodiment, the bed further comprises a sloping edge  28  extending from one or more edges of the bed  26 . In some embodiments the sloping edge  28  extends from more than one edge of bed, and in other embodiments still the sloping edge  28  extends from three edges of the bed: the two long edges of the bed  26  and the shorter edge furthest from the radiation beam  16  (see  FIG. 2 ). According to some embodiments of the invention, one or more control screens  30  are arranged on the sloping edge  28 . The system  10  may comprise a single control screen  30 , or multiple control screens arranged around multiple edges of the bed  26 . In one embodiment (see  FIG. 2 ), a control screen  30  is arranged on the sloping edge  28  on each of three edges of the bed: the two long edges of the bed  26  and the shorter edge furthest from the radiation beam  16 . The control screens  30  may be used to control the system  10  in a manner to be described in greater detail below. The screen  30  comprises a display and one or more mechanisms for detecting the presence and orientation of a control device, as will be described below. In other embodiments, the control screens may be arranged on a console adjacent to and separate from the patient support  20  rather than on one or more edges of the bed  26 . The height of the console and the patient support may be adjusted separately as required by the user. 
         [0022]    In the control room, a control console  32  allows a technician to control the system  10 . The console  32  comprises a control screen  34 , and this is similar in construction and operation to the control screens  30  positioned around the patient bed  26 . A control device  36  is placed on the control screen  34 , and cooperates with it to input signals from a technician to control the system  10 . The control device  36  can also be placed on the control screens  30 , next to the patient bed, in order to control the system in a similar manner. Again, this aspect will be described in greater detail below. 
         [0023]    The control device  36  comprises a wireless beacon (not illustrated in  FIGS. 1 and 2 ), which can be detected in order to localize the device&#39;s position in the treatment and/or control rooms. In the treatment room, therefore, a detection system  38  is provided having one or more antennas  39 , in order to detect the presence and location of the control device  36 . In the control room, a similar detection system  40  is provided, also having one or more antennas  41 . 
         [0024]      FIGS. 3   a  and  3   b  show in more detail the control device  36  according to some embodiments, when positioned on a control screen  30 ,  34 . 
         [0025]    The device  36  has a bottom surface  50 , a top surface  52 , and one or more side surfaces  54 . In the illustrated embodiment, the device  36  is cylindrical (see  FIG. 2  for example) although in practice it can take any shape. In some embodiments, the device  36  has chamfered edges  56  connecting at least the bottom surface  50  to the one or more side surfaces  54 , so that the device  36  can be easily tilted. 
         [0026]    The device  36  further comprises a wireless beacon  58  having an antenna  59 . In some embodiments, the beacon  58  is a radio frequency ID tag. The beacon  58  may comprise a memory which can store identification data corresponding to the identity of the user of the device  36 . The beacon  58  can further interact wirelessly with the detection systems  38 ,  40  in order to accurately locate the device  36  within the treatment room or the control room. Note that the systems  38 ,  40  can be located anywhere within the treatment room and control room respectively. For example, the system  38  may be arranged within the patient support  20 . 
         [0027]    The device  36  further comprises one or more magnetic elements  60  located in or near the bottom surface  50 . The one or more magnetic elements  60  serve to secure the device  36  magnetically with respect to the control screen  30 ,  34 , and also to allow the control screen to determine the device&#39;s orientation (e.g. its angle of rotation and its direction of tilt). 
         [0028]    In the illustrated embodiment, the device further comprises a fingerprint reader  62  which may be located in or near the top surface  52 . The device may also comprise a power source (not illustrated). 
         [0029]    The screen  30 ,  34  comprises a display  64  which can be used to display a graphical user interface for controlling the system  10  as will be described below. None of the display circuitry is illustrated for clarity. A plurality of elements are arranged beneath the display  64 , and these cooperate with the one or more magnetic elements  60  in the device  36  to determine the angle of rotation and tilt of the device  36 , and to secure the device  36  to the screen  30 ,  34 . For example, a magnetic element  66  is disposed beneath the device  36 , with its polarity arranged so as to attract the one or more magnetic elements  60  in the device  36 . In this way the device is secured to the screen  30 ,  34  (recalling that the screen  30 ,  34  may be placed at an angle as shown in  FIGS. 1 and 2 ). Further, a plurality of magnetic sensors  68  are provided in order to detect the magnetic field generated by the one or more magnetic elements  60  and so determine the orientation of the device  36 . This aspect is covered more fully in  FIGS. 3   b  and  4 . In an alternative or additional embodiment, resistive or capacitive touch or proximity sensors may be disposed in the vicinity of the device, which can be used to determine the tilt and/or position of the device. 
         [0030]      FIG. 4  shows a bird&#39;s eye view of the control device  36  located on a portion of the control screen  30 ,  34 . While the control screen includes a display  64 , this is not illustrated for clarity in order to show the components of the screen  30 ,  34  beneath the display. 
         [0031]    In the embodiment illustrated in  FIG. 4 , the one or more magnetic elements  60  within the device  36  comprise a first magnet  60   a  oriented substantially parallel to the bottom surface  50  (i.e. such that the magnetic moment lies substantially parallel to the bottom surface  50 ), and a second magnet  60   b  oriented substantially orthogonal to the bottom surface  50  (i.e. such that the magnetic moment lies substantially orthogonal to the bottom surface  50 ). The second magnet  60   b  is attracted by the magnetic field generated by the magnetic element  66  in the screen  30 ,  34 , and this secures the device  36  to the screen  30 ,  34 . 
         [0032]    The screen  30 ,  34  comprises a plurality of magnetic sensors  68  arranged in a ring about the magnetic element  66 . In some embodiments, the plurality of magnetic sensors are arranged in a plurality of pairs  68   a ,  68   b  of magnetic sensors, with sensors in each pair being arranged on opposite sides of the ring. 
         [0033]    The magnetic field generated by the first magnet  60   a  is asymmetric in the plane of the sensors  68 , and thus data from the sensors can be used to determine the angle of rotation of the device, i.e. the angle of rotation about the axis II. Further, as can be seen with respect to  FIG. 3   a , tilting the device  36  moves the ends of the first magnet  60   a  nearer and further from corresponding sensors of a sensor pair  68   a . This tilt can therefore be detected by comparing the magnetic field sensed by corresponding sensors of the sensor pair  68   a.    
         [0034]    The control device  36  can therefore be used to issue commands via the control screen by rotating the device  36  and/or by tilting the device  36 .  FIG. 5  illustrates an example graphical user interface employing these controls. 
         [0035]    The device  36  is placed in a particular location on the screen  30 ,  34 , above the magnetic element  66 . One or more menus  70  are displayed on the screen around the device  36 , with one of the menus being highlighted (in the top-right corner). In an embodiment, the user interface may only be displayed in response to the magnetic sensors  68  detecting the presence of a control device  36 . When the device is removed, the user interface may also be removed. In the illustrated embodiment, each menu comprises a number of items and one item in each menu is highlighted. Each menu may correspond to a particular component of the system, and the items within the menu correspond to particular values or inputs for that component. Alternatively, each menu may correspond to a particular area of interest, such as the treatment plan, the system  10 , the expected dosage profiles, etc, and clicking on each item within the menus may lead to further submenus opening. Those skilled in the art will appreciate that there are many different options for organizing the menu structure and the invention is not limited to any one of them. 
         [0036]    By rotating the device around the axis II, the device  36  can be used to highlight a particular menu, or highlight a particular item within a menu, for example. By tilting the device  36  towards a particular menu or a particular item, that menu or item can be selected. 
         [0037]    In use, the device  36  is associated with a particular radiotherapy professional. The association may be permanent (i.e. such that the device  36  belongs to a single professional and is not generally used by others) or transitory (i.e. such that the device  36  is associated with a single professional only for one or more sessions). The identity of the professional can be loaded into the device  36  through the beacon  58 . For example, where the beacon  58  comprises an RFID tag, an RFID reader (not illustrated) can be used to load the data onto the device. In one embodiment, the identity of the professional can be confirmed through the fingerprint reader  62 . 
         [0038]    Each professional employed in the therapy suite will have a particular role which is associated with certain duties and responsibilities. For example, a qualified technician may need access to all regular controls of the system  10 ; a trainee technician may be allowed access only to a subset of those controls (e.g. not including the ability to commence treatment); a repair technician may require access to additional controls to allow effective maintenance of the system  10 . Each user identity is therefore also granted a level of access to the system commensurate with that user&#39;s experience and role within the therapy suite. 
         [0039]    In some embodiments, the menus displayed on the screen  30 ,  34  may therefore depend on the identity of the user associated with the particular device  36 . The systems  38 ,  40  register the location of the device within the therapy suite, and also the identity of the user of the device  36 . In some embodiments the systems  38 ,  40  may also identify whether that identity has been confirmed by the fingerprint reader  62 . Once the information on the user identity is known, appropriate menus can be displayed on the screen  30 ,  34  around the device  36 . 
         [0040]    In other embodiments, the displayed menus may not depend on the identity of the user, but the user may be prevented from selecting or accessing controls where he or she is not authorised. 
         [0041]    In some embodiments, the system  10  may record a log of which user makes which inputs using the device  36 . Should an error occur, the log can be reviewed to determine which user input the incorrect commands. 
         [0042]    In some embodiments, the menus displayed on the screen  30 ,  34  may also depend upon which screen the device  36  is placed. For example, in one embodiment, screens  30  on the patient support  20  may only display control information relating to the patient support  20 . Thus when the device  36  is placed on one of those screens  30 , the menus which are displayed allow the device to control the position and orientation of the bed  26  but not other aspects of the system  10 . In contrast, the screens  34  in the control room may provide for control over more components of the system  10 , or even the entire system  10 . 
         [0043]    As use of the device  36  can grant access to certain parts of the system  10 , depending on the identity of the user, in some embodiments a mechanism is provided to ensure the device  36  remains attached to or within a certain distance of the user. For example, in one embodiment (see  FIG. 6 ) the device  36  comprises two parts  36   a ,  36   b . The first part  36   a  corresponds to the device as described in the embodiments of  FIGS. 3   a  and  3   b . The second part  36   b  comprises a cord  80  and a transceiver  82 , and is detachably connected to the first part  36   a . The cord  80  allows the device  36  to be worn around the user&#39;s neck or wrist so that the second part  36   b  at least remains attached to the user at all times. Those skilled in the art will appreciate that alternative means may be provided to attach the second part  36   b  to the user. In use, the first part  36   a  can be detached from the second part  36   b , to allow the first part  36   a  to be placed on the control screens  30 ,  34  and used to control the system  10  in the manner described above. To ensure the first part  36   a  remains within the control of the user, the transceiver  82  may periodically transmit a polling signal to the first part  36   a , and particularly the beacon  58 . In response to the polling signal, the beacon  58  may transmit an answer signal which is received by the transceiver  82 , thus ensuring that the first part  36   a  is not too distant from the second part  36   b  (and implicitly the user). If the answer signal is not received, or the signal is received with a signal strength which is below a threshold, the second part  36   b  may deem that the first part  36   a  is too distant from the user, and issue an alarm. For example, the second part  36   b  may vibrate, sound an alarm noise, or provide visual feedback. 
         [0044]    Embodiments of the invention therefore provide a mechanism for controlling access to a radiotherapy system. In some embodiments, the mechanism allows control of the system only to those who are duly authorised and records which users make which inputs. Within the treatment room, the control mechanism is provided by way of one or more display screens which can be easily cleaned in contrast to conventional knobs and buttons. 
         [0045]    Those skilled in the art will appreciate that various amendments and alterations can be made to the embodiments described above without departing from the scope of the invention as defined in the claims appended hereto.