Abstract:
This invention provides an X-ray CT apparatus which can be mounted in a motor vehicle, trailer, or container, including locking mechanisms for locking at least some of the movable portions of the X-ray CT apparatus, detectors for detecting the locking/unlocking states of the locking mechanisms, and a notifying unit for representing the states of the locking mechanisms on the basis of outputs from the detectors. Collision of an unlocked movable portion with its periphery during traveling can be avoided.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2000-182564, filed Jun. 19, 2000; No. 2000-182566, filed Jun. 19, 2000; and No. 2001-056268, filed Mar. 1, 2001, the entire contents of all of which are incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to an onboard X-ray CT apparatus which can be mounted in a motor vehicle, trailer, or container, a container for mounting the X-ray CT apparatus, and a motor vehicle for mounting the X-ray CT apparatus.  
           [0003]    X-ray CT apparatuses for obtaining the tomographic image of an object to be examined by exposing the object from his/her surroundings to X-rays, measuring the amount of X-rays having passed through the object, and performing image reconstruction processing for the obtained projection data by using a computer are effective for detection of a disease in its early stage and determination of an appropriate therapeutic plan. Further, a so-called X-ray CT apparatus onboard vehicle, e.g., a motor vehicle such as a bus which contains an X-ray CT apparatus is moved to a disaster-stricken area where image diagnosis for the presence/absence of a fracture or an injury to a viscus is done. Such a motor vehicle is also exploited for itinerant diagnosis or group examination in a depopulated area such as a mountainous area.  
           [0004]    Recently, the development of helical scanning X-ray CT apparatuses enables photographing in a pectoral region within one breath. Along with this, strong demands have arisen for implementation of an X-ray CT apparatus onboard vehicle which contains a helical scanning X-ray CT apparatus for group examination in order to detect a pectoral disease in its early stage.  
           [0005]    A known example of a conventional X-ray CT apparatus onboard vehicle is disclosed in Utility Model Registration No. 3,027,769, and schematically shown in FIG. 1. A gantry  2   a  and bed  2   b  of an X-ray CT apparatus are mounted at the center of a large-bus type vehicle  1  in the longitudinal direction. A power supply device  3  and high-voltage generator  4  are installed in the space between a driver&#39;s seat  18  at the front portion of the vehicle and the gantry  2   a  and bed  2   b.  An X-ray monitor  5  and console  6  are installed at the back portion of the vehicle  1 . A doorway  12  and lift device  15  for an object who uses a stretcher or wheelchair are formed in the back wall surface of the vehicle  1 . A doorway  13  for an object who can walk by himself/herself is also formed in the backward side wall surface of the vehicle  1 .  
           [0006]    Other X-ray CT apparatus onboard vehicles are disclosed in Jpn. Pat. Appln. KOKAI Publication Nos. 6-154202 and 8-127282.  
           [0007]    In the X-ray CT apparatus onboard vehicle disclosed in Utility Model Registration No. 3,027,769, the power supply device  3  is installed in the same room as the gantry  2   a  and bed  2   b  of the X-ray CT apparatus, which impairs safety and gives annoying noise to an object during an examination.  
           [0008]    The X-ray CT apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. 6-154202 performs X-ray CT photographing while an object sits on a chair, and is not suitable for X-ray CT photographing of a severely wounded object. The X-ray CT apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-127282 is an industrial X-ray CT apparatus mounted in a large trailer, and is not suited for itinerate diagnosis or group examination in a depopulated area such as a mountainous area owing to the road situation.  
           [0009]    These conventional X-ray CT apparatus onboard vehicles do not consider any protection means for the movable portions of the mounted X-ray CT apparatuses, and the movable portions of the X-ray CT apparatuses may be damaged by vibrations or shocks during traveling of the X-ray CT apparatus onboard vehicle.  
           [0010]    In the conventional X-ray CT apparatus onboard vehicles, a CT operation room and the like are designed in accordance with a mounted X-ray CT apparatus, which makes it difficult to exchange the X-ray CT apparatus with another type apparatus upon upgrading the apparatus.  
         BRIEF SUMMARY OF THE INVENTION  
         [0011]    It is an object of the present invention to provide an X-ray CT apparatus suitably mounted in a motor vehicle, trailer, or container.  
           [0012]    According to the present invention, there is provided an X-ray CT apparatus which can be mounted in a motor vehicle, trailer, or container, comprising locking mechanism unit for locking at least one of movable portions of the X-ray CT apparatus, detectors for detecting locking states of the locking mechanism unit, and a notifying unit for representing the states of the locking mechanism unit on the basis of outputs from the detectors.  
           [0013]    Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0014]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.  
         [0015]    [0015]FIG. 1 is a plan view for explaining a conventional X-ray CT apparatus onboard vehicle;  
         [0016]    [0016]FIG. 2 is a plan view showing an X-ray CT apparatus onboard vehicle according to an embodiment of the present invention;  
         [0017]    [0017]FIG. 3 is a side view of FIG. 2;  
         [0018]    [0018]FIG. 4 is a perspective view showing a CT scanner in FIG. 2;  
         [0019]    [0019]FIG. 5 is a plan view showing the interior of a gantry in FIG. 2;  
         [0020]    [0020]FIG. 6 is a side view showing a tilt mechanism in FIG. 5;  
         [0021]    [0021]FIG. 7 is a plan view showing a locking mechanism in FIG. 5;  
         [0022]    [0022]FIG. 8 is a block diagram showing a traveling control system according to the embodiment of the present invention;  
         [0023]    [0023]FIG. 9 is a circuit diagram showing part of the traveling control system in FIG. 8;  
         [0024]    [0024]FIG. 10 is a perspective view showing an operation room in FIG. 2;  
         [0025]    [0025]FIG. 11 is a view showing the layout of a pitch below the vehicle floor in FIG. 2;  
         [0026]    [0026]FIG. 12 is a block diagram showing a movable portion control system according to the embodiment of the present invention;  
         [0027]    [0027]FIG. 13 is a flow chart showing control of a movable portion by a scan controller in FIG. 12;  
         [0028]    [0028]FIG. 14 is a flow chart showing photographing condition control by the scan controller in FIG. 12; and  
         [0029]    [0029]FIG. 15 is a view for explaining a medical image information transfer method according to another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]    The present invention can be applied to an X-ray CT apparatus which can be mounted in a motor vehicle, trailer, or container, and a motor vehicle, trailer, or container for mounting the X-ray CT apparatus. A motor vehicle which contains an X-ray CT apparatus will be described.  
         [0031]    (First Embodiment)  
         [0032]    [0032]FIG. 2 is a plan view showing the overall layout of an x-ray CT apparatus onboard vehicle according to the first embodiment. FIG. 3 is a side view of the X-ray CT apparatus onboard vehicle. In FIG. 2, the ceiling of the vehicle is not illustrated. In an X-ray CT apparatus onboard vehicle  1100  according to the first embodiment, a CT operation room  120  is formed at almost the center of a motor vehicle such as a large bus having a driver&#39;s seat  1110  at the front portion. A power supply room  130 , part of which has a two-layered structure, is formed between the driver&#39;s seat  110  and the CT operation room  120 . A staff room  140  is formed after the CT operation room  120 . A doorway  150  for an object is formed in the back wall of the motor vehicle so as to communicate with the staff room  140 . The staff room  140  also serves as a dressing room for an object.  
         [0033]    The CT operation room  120  has the largest space in the motor vehicle where a gantry  121  and bed  122  of an X-ray CT apparatus are installed and fixed to the floor, and an air-conditioning system  123  and switchboard  124  are also installed. In general, the X-ray CT apparatus is constituted by the gantry  121 , the bed  122 , and a console  141 . The console  141  is arranged in the staff room  140 , as will be described later.  
         [0034]    [0034]FIG. 4 is an enlarged view showing part of the gantry  121  and bed  122  installed in the CT operation room  120 . A through hole  121   a  serving as a photographing port is formed at the center of the gantry  121 , and an object on a top plate  122   a  of the bed  122  is fed into the photographing port  121   a  by sliding the top plate  122   a.  The slide stroke of the top plate  122   a  to the photographing port  121   a  can be properly set by the spatial conditions of the CT operation room  120 , e.g., the distance between the gantry  121  and a partition wall  120   a  which partitions the CT operation room  120  from the power supply room  130 .  
         [0035]    This is because the size of the gantry  121  is supposed to change depending on the type of motor vehicle or the type of X-ray CT apparatus installed in the CT operation room  120 . When the CT operation room  120  is small, the top plate  122   a  which slides is prevented from interfering with partition wall  120   a.    
         [0036]    To allow an object to easily get on and off the bed  122 , the bed  122  is equipped with an interlock circuit so as to move the bed  122  down to almost 35 cm above the floor while the top plate  122   a  is retracted, and to prevent slide of the top plate  122   a  unless the bed  122  moves up to a predetermined height.  
         [0037]    Although not shown, the gantry  121  has a rotating ring to which an X-ray tube and X-ray detector are attached to face each other via the photographing port  121   a.  The gantry  121  incorporates a driving unit for driving the rotating ring, a tilt mechanism for tilting the gantry  121 , a high-voltage generator for generating a high voltage to be applied to the X-ray tube, and a signal amplifier for amplifying a signal detected by the X-ray detector. The tilt angle of the tilt mechanism can also be properly set in accordance with the spatial conditions of the CT operation room  120  in order not to interfere with the ceiling and partition wall  120   a  of the CT operation room  120  even if a different type of gantry  121  is installed in the CT operation room  120 , similar to the bed  122  and top plate  122   a.    
         [0038]    The surface of the gantry  121  has a cover, which is divided into a front cover  121   b,  side cover  121   c,  upper cover  121   d,  and back cover  121   e.  In general maintenance, as shown in FIG. 2, the front cover  121   b  is opened toward the ceiling of the motor vehicle so as to enable access to an internal device from the front side.  
         [0039]    A handle  121   f  of the tilt locking mechanism projects from the side cover  121   c  of the gantry  121 . The handle  121   f  of the locking mechanism can be rotated clockwise or counterclockwise to lock the tilting gantry  121  or unlock the gantry  121 . Operating the handle  121   f  can easily switch the gantry  121  between a locking state and an unlocking state. While the X-ray CT apparatus onboard vehicle  1100  travels, the gantry  121  can be locked to suppress collision between the gantry  121  and another portion within a small space, and vibrations which degrade the movable portions of the gantry  121  due to metal fatigue or the like. When the X-ray CT apparatus onboard vehicle  1100  stops at a predetermined position and the X-ray CT apparatus is to operate, the gantry  121  can be easily unlocked.  
         [0040]    In photographing by the X-ray CT apparatus, the gantry  121  is tilted to a predetermined angle by the tilt mechanism, as needed. At this time, the gantry  121  is fixed by a brake, which is different from locking operation of the tilt mechanism using the handle  121   f  as the locking mechanism.  
         [0041]    [0041]FIGS. 5, 6, and  7  show the tilt locking mechanism. The rotating ring has the X-ray tube and X-ray detector. This rotating ring is rotatably supported by a ring frame  100 . Arcuated rails  101  are attached to the right and left sides of the ring frame  100 . Each rail  101  is set on rollers  104  pivotally fixed to a side plate  103  of a base stand  102 . The rails  101  move on the rollers  104  to tilt the ring frame  100  forward and backward.  
         [0042]    Each locking plate  105  is movably held at the gap between the rail  101  and the side plate  103  of the base stand  102 . When the handle  121   f  is rotated clockwise, the locking plate  105  comes close to the rail  101 , and when the handle  121   f  is rotated counterclockwise, the locking plate  105  moves apart from the rail  101  and comes close to the side plate  103 . When the locking plate  105  comes into contact with the rail  101 , a locking pin  109  of the locking plate  105  fits in a pin hole  110  of the rail  101 . Then, the x-ray CT apparatus onboard vehicle  100  is fixed. The position of the pin hole  110  is designed such that the ring frame  100  has a tilt angle of 0°, i.e., stands vertically upon fixing.  
         [0043]    When the locking plate  105  moves apart from the rail  101 , the locking pin  109  of the locking plate  105  comes out of the pin hole  110  of the rail  101 , and the ring frame  100  freely tilts.  
         [0044]    A first microswitch SW 1  detects a tilt-locking state, and is designed to be turned on when the locking plate  105  comes into contact with the rail  101  and be turned off when the locking plate  105  moves apart from the rail  101 . A second microswitch SW 2  detects a state wherein the tilt-locking state is completely released, and is designed to be turned on when the locking plate  105  comes into contact with the side plate  103  and be turned off when the locking plate  105  moves apart from the side plate  103 . The two switches SW 1  and SW 2  can accurately detect three states, i.e., a locking state, unlocking state, and intermediate state wherein neither locking or unlocking is completed. The locking state corresponds to the ON state of the first microswitch SW 1  and the OFF state of the second microswitch SW 2 . The unlocking state corresponds to the OFF state of the first microswitch SW 1  and the ON state of the second microswitch SW 2 . The intermediate state corresponds to the OFF states of both the first and second microswitches SW 1  and SW 2 .  
         [0045]    Whether the handle  121   f  is in the locked, unlocked, or intermediate state of the tilt mechanism is displayed on a display  125  so as to prevent the operator from misunderstanding the state at the start of traveling the X-ray CT apparatus onboard vehicle  100  or at the start of operating the X-ray CT apparatus. More specifically, when the first microswitch SW 1  is turned on, the display  125  displays that the tilt mechanism is kept locked and a so-called locking mechanism is operating. When the second microswitch SW 2  is turned on, the display  125  displays that the tilt mechanism is unlocked and the locking mechanism is kept stopped. When the tilt mechanism is being locked or unlocked or is not reliably locked or unlocked, both the first and second microswitches SW 1  and SW 2  are OFF. At this time, the display  125  receives a signal via a NOR gate G 1  and displays that the locking mechanism is abnormal.  
         [0046]    As shown in FIG. 8, the display  125  includes a display  202  set at the driver&#39;s seat and a display  203  installed in the CT operation room. The display  203  displays the three states of the tilt locking mechanism so as to distinguish them. Similarly, the display  202  at the driver&#39;s seat displays the three states of the tilt locking mechanism so as to distinguish them. Note that the display  203  in the CT operation room may display the three states of the tilt locking mechanism so as to distinguish them, and the display  202  may simply display a message “traveling is ready.” upon completely locking the tilt locking mechanism because the driver needs information about whether traveling is enabled or disabled.  
         [0047]    Instead of displaying a locking-state message, the message may be output by sounds or may be displayed and output by sounds.  
         [0048]    The first embodiment uses the operation signals of the first and second microswitches SW 1  and SW 2  to enable the operation of the X-ray CT apparatus, i.e., photographing operation and enable traveling the X-ray CT apparatus onboard vehicle  1100 , i.e., motor vehicle. As shown in FIG. 8, a traveling control circuit  201  outputs a traveling enable signal to an engine starter control circuit  111  of the vehicle  1100  when the first microswitch SW 1  is ON and the second microswitch SW 2  is OFF. Upon reception of the traveling enable signal, the engine starter control circuit  111  permits activation of the starter, i.e., activation of the engine. In another state, the traveling control circuit  201  outputs a traveling disable signal to the engine starter control circuit  111  of the vehicle. Upon reception of the traveling disable signal, the engine starter control circuit  111  does not permit activation of the starter. Thus, no driving power is supplied to the starter to inhibit activation of the engine.  
         [0049]    More specifically, as shown in FIG. 9, a signal from the first microswitch SW 1  is supplied to the engine starter control circuit  111  of the motor vehicle and an emergency stop circuit  141   g  of a controller  141   b  of the X-ray CT apparatus. For example, if the first microswitch SW 1  outputs an ON signal (H level), the starter control circuit  111  is turned on to enable traveling the motor vehicle, and at the same time the emergency stop circuit  141   g  is turned on via a gate G 2  to inhibit photographing operation of the X-ray CT apparatus. If an output from the first microswitch SW 1  is an OFF signal (L level), a gate G 3  operates to turn off the starter control circuit  111  and inhibit activation of the engine, and the emergency stop circuit  141   g  is not turned on.  
         [0050]    A signal from the second microswitch SW 2  is also supplied to the emergency stop circuit  141   g  of the controller  141   b  of the X-ray CT apparatus and the engine starter control circuit  111  of the motor vehicle. For example, if the second microswitch SW 2  outputs an ON signal (H level), the emergency stop circuit  141   g  of the X-ray CT apparatus is turned off to normally operate the X-ray CT apparatus, and at the same time the starter control circuit  111  is turned off via the gate G 3  to inhibit activation of the motor vehicle. If an output from the second microswitch SW 2  is an OFF signal (L level), the gate G 2  operates to turn on the emergency stop circuit  141   g  and inhibit operation of the X-ray CT apparatus, and the starter control circuit  111  is kept off to inhibit activation of the engine of the motor vehicle.  
         [0051]    Accordingly, when both the first and second microswitches SW 1  and SW 2  are OFF, neither the operation of the X-ray CT apparatus nor traveling of the motor vehicle is enabled.  
         [0052]    A ring block mechanism for locking the rotating ring to the ring frame  100  when the X-ray CT apparatus onboard vehicle  100  travels and unlocking the rotating ring when the X-ray CT apparatus operates is incorporated in the gantry  121  for the rotating ring to which the X-ray tube and X-ray detector described above are attached to face each other via the photographing port  121   a.  This ring block mechanism may be a mechanical locking means such as a locking pin &amp; hole structure similar to that of FIG. 7, but may be an electromagnetic brake for applying the brake in the OFF state and releasing the brake in the ON state. In this case, ON/OFF operation is done by operating operation switches on the front cover  121   b  or performing remote control from the staff room  140 . The rotating ring is desirably locked by the protection means at a position where the X-ray tube and X-ray detector attached to the rotating ring so as to face each other become perpendicular to the gantry  121 , i.e., almost perpendicular to the floor surface of the motor vehicle  100 .  
         [0053]    To detect and distinguish the three states of the lock, i.e., the locking state, unlocking state (free rotation state), and intermediate state of the rotating ring, a pair of microswitches SW 11  and SW 12  are adopted. The traveling control circuit  201  supplies a traveling enable or disable signal to the engine starter control circuit  111  in accordance with the states of the two microswitches SW 11  and SW 12 . The displays  202  and  203  display the locking state.  
         [0054]    The bed is provided with a mechanism of locking slide of the top plate and a mechanism of locking elevation of the top plate. The slid locking mechanism and elevation locking mechanism may be mechanical locking means such as a locking pin &amp; hole structure similar to that of FIG. 7, or may be electromagnetic brakes. A pair of microswitches SW 21  and SW 22  (SW 31  and SW 32 ) are employed to detect and distinguish the three states of the lock, i.e., the locking state, unlocking state, and intermediate state of each of slide and elevation. The traveling control circuit  201  supplies a traveling enable or disable signal to the engine starter control circuit  111  in accordance with the states of the pair of microswitches SW 21  and SW 22  (SW 31  and SW 32 ). The displays  202  and  203  display the three, locking, unlocking, and intermediate states so as to distinguish them.  
         [0055]    The keyboard and mouse in the CT operation room also comprise locking means, as will be described in detail later. The locking means is typically a rubber band for the keyboard, and a mouse pocket for the mouse. Each switch SW 41  is attached to a hook for hanging the rubber band. If the rubber band is hung on the hook via the keyboard, the hook switch SW 41  is turned on by the tension. A mouse pocket switch SW 51  is attached to the bottom of the mouse pocket. If the mouse is put into the mouse pocket, the mouse pocket switch SW 51  is turned by the weight.  
         [0056]    The traveling control circuit  201  can determine based on outputs from SW 41  and SW 51  whether the keyboard and mouse are locked. When the hook switch SW 41  is OFF, the traveling control circuit  201  displays on the displays  202  and  203  a message that the keyboard is not locked. When the mouse pocket switch SW 51  is OFF, the traveling control circuit  201  displays on the displays  202  and  203  a message that the mouse is not put into the pocket. However, the traveling control circuit  201  does not output any traveling disable signal even if the keyboard is not fixed. Similarly, the traveling control circuit  201  does not output any traveling disable signal even if the mouse is not put into the pocket. This is because even if the keyboard and mouse move during traveling, this does not cause any serious accident, and the user may arbitrarily use another convenient locking means.  
         [0057]    Referring back to FIG. 2, the power supply room  130  will be described.  
         [0058]    The power supply room  130  is located between the driver&#39;s seat  110  and the CT operation room  120 , and partially formed from a two-layered structure. A power supply device  131  including a power generator is installed at the lower layer part of the power supply room  130 , and an air-cooling system  132  such as a fan for cooling the power supply device  131  is installed at the upper layer part. Since the power supply room  130  has a two-layered structure and the power supply device  131  as a heavy device is arranged at the lower layer part in a direction perpendicular to the longitudinal direction of the motor vehicle, the space efficiency of the motor vehicle increases. Since the power supply room  130  is an independent room, the object in the CT operation room  120  does not feel discomfort due to noise, and the safety also increases.  
         [0059]    The power supply room  130  supplies necessary power to the each building device of the X-ray CT apparatus. The space of the power supply room  130  is restricted, a large-size power supply device  131  is difficult to install, and sufficient power cannot always be supplied. For this reason, the X-ray CT apparatus onboard vehicle  100  of the present invention can adjust the load in accordance with the capacity of the power supply device  131 , and the adjusting means will be described later.  
         [0060]    The staff room  140  formed after the CT operation room  120  will be described. The staff room  140  is mainly used by medical staff such as a doctor and technician in order to operate the X-ray CT apparatus or read and project an acquired CT image. In the staff room  140 , the console  141  of the X-ray CT apparatus, a monitor  142  for displaying a CT image, and various devices  143  such as a computer-assisted diagnostic system (lung cancer CAD)  143   a  for examining a lung cancer, communication system  143   b,  and analyzer  143   c  are aligned along one side wall surface of the staff room  140 , in other words, along one side wall surface of the motor vehicle in the longitudinal direction.  
         [0061]    [0061]FIG. 10 is an enlarged view showing the console  141  installed in the staff room  140 . The console  141  has a table  141   a,  a controller  141   b  below the table  141   a,  and a keyboard  141   c  and mouse  141   d  on the table  141   a.  The monitor  142  and the monitors of the devices  143  are also located on the table  141   a.    
         [0062]    Various setting operations of the X-ray CT apparatus, e.g., setting of a tube voltage and tube current for setting the conditions of X-rays emitted from the X-ray tube inside the gantry  121 , setting of the slide stroke of the top plate  122   a  for positioning a portion to be photographed to the photographing port  121   a,  and setting of the number of shots are designated and input to the controller  141   b  by the medical staff by using the keyboard  141   c  and mouse  141   d.  At this time, the controller  141   b  determines based on the input tube voltage and tube current whether the load falls within the capacity of the power supply device  131 , and if determining that the load exceeds the power supply capacity, outputs a warning to suspend X-ray exposure. If the medical staff changes the settings and the controller  141   b  determines that the load falls within the power supply capacity, X-rays are normally emitted to acquire CT data.  
         [0063]    As described above, the X-ray CT apparatus onboard vehicle  100  supplies power to associated equipment such as the X-ray CT apparatus from the power supply device  131  including the mounted power generator, but the power supply capacity is limited. If X-rays are emitted under the maximum output condition of a general X-ray CT apparatus, the apparatus may be overloaded. If the overloading state repetitively occurs, this may cause the failure of the power supply device  131 . Moreover, the power supply may stop to cause the malfunction of the computer or delete acquired important image data. To prevent this, power consumption including power of associated equipment is calculated from necessary power based on X-ray exposure conditions which require the maximum power, and whether the load falls within the capacity of the power supply device  131  is checked.  
         [0064]    The monitor  142  is integrally fixed by two rubber bands  144   a  and  144   b  to a swing portion  144  fixed to the table  141   a  rotatably in the horizontal direction. The direction of the monitor  142  can be freely changed together with the swing portion  144  within a predetermined range in the horizontal direction on the table  141   a.  This can increase the operability in use while protecting the monitor  142  from traveling vibrations.  
         [0065]    A microphone  141   e  for communication between the object under examination in the CT operation room  120  and the medical staff in the staff room  140  is fixed onto the table  141   a.  When the mouse  141   d  is not used, it is stored in a mouse pocket  141   f  fixed to the side surface of the monitor  142 , as shown in FIG. 10. The mouse pocket switch SW 51  is attached to the bottom of the mouse pocket  141   f.    
         [0066]    [0066]FIG. 10 shows a state wherein the keyboard  141   c  is fixed by a fixing rubber band  144   c  interposed between the swing portion  144  and the table  141   a  when the X-ray CT apparatus onboard vehicle  1100  travels. To operate the X-ray CT apparatus, the rubber band  144   c  is removed. The rubber band  144   c  is hung on hooks  144   g.  The hook switches SW 41  are attached to the hooks  144   g,  and turned on by hanging the rubber band  144   c  to the hooks  144   g  via the keyboard  141   c.  The rubber band  144   c  has a tension when pulled into an almost V shape, and fixes not only the keyboard  141   c  but also the monitor  142  together with the swing portion  144  so as to stand traveling vibrations.  
         [0067]    Conventionally, when the X-ray CT apparatus onboard vehicle  100  travels, the keyboard  141   c  and mouse  141   d  are removed from connectors and stored in a protection case, and when the X-ray CT apparatus is to operate, are connected again, which is cumbersome. However, fixing by the rubber band  144   c  and storage into the mouse pocket  141   f  can eliminate cumbersome work and the space of the protection case, thus effectively using the space.  
         [0068]    Similar to the monitor  142  and keyboard  141   c  shown in FIG. 10, the monitors of the devices  143  are attached to swing portions on the table  141   a,  and their keyboards are also fixed by fixing bands. However, these monitors and keyboards are not illustrated in FIG. 5.  
         [0069]    The bottom of the controller  141   b  below the table  141   a  is fit in and fixed to two guide plates  145  fixed to the floor of the staff room  140  via rubber vibration insulators. Although not shown, rollers are arranged on the upper surfaces of the guide plates  145 .  
         [0070]    A sloped base plate attached to the bottom of the controller  141   b  is slid on the rollers and moved in the direction indicated by the arrow, thereby fitting and fixing the controller  141   b  at a predetermined position. In maintenance, one side of the controller  141   b  is lifted to extract the controller  141   b  to the left (direction opposite to the arrow) in FIG. 10, and the controller  141   b,  which has a caster at the bottom, can be easily moved to the space left to the table  141   a.    
         [0071]    The guide plates  145  can fix the controller  141   b  without projecting from the bottom of the controller  141   b,  and can contribute to space reduction in the staff room  140 .  
         [0072]    As shown in FIG. 2, a dressing space  146  is formed along the side wall opposite to the wall along which the devices  143  including the console  141  of the staff room  140  are aligned. A movable shielding member such as a curtain  147  is disposed to partition the dressing space  146  and the devices  143  aligned along the wall surface, as needed. A fixed chair  146   a  is set in the dressing space  146 .  
         [0073]    In the staff room  140 , the console  141 , monitor  142 , and devices  143  are aligned along one wall surface. The medical staff can perform work while facing the wall surface and watching the monitor  142  and the screens of the devices  143 , and the internal space of the staff room  140  can be widely used. Hence, the staff room  140  can also serve as the dressing room  146 , as needed. At this time, the dressing space  146  is shielded from the monitor  142  and devices  143  by the curtain  147  to prevent another object from seeing a diagnostic image and protect the privacy of the object.  
         [0074]    The doorway  150  is formed in the back wall of the motor vehicle so as to communicate with the center of the staff room  140 . The doorway  150  has steps  151  which are stored in the vehicle when not used.  
         [0075]    A pit serving as a layout means for a power supply cable and a cable for connecting the gantry  121  and bed  122  of the X-ray CT apparatus to the console  141  will be explained. FIG. 11 is a view showing a pit formed below the floors of the CT operation room  120  and staff room  140 . A hatched portion is a pit  160 . The pit  160  extends below the partition wall  120   a  from the power supply room  130  to the CT operation room  120 , is formed along the partition wall  120   a,  so bends as to extend below the gantry  121 , extends straight along the bed  122  so as to detour the rear wheel of the motor vehicle, and further bends to reach the installation position of the switchboard  124 . Further, the pit  160  extends below a partition wall  120   b  between the CT operation room  120  and the staff room  140 , and bends to reach the console  141  along the partition wall  120   b  on the staff room  140  side.  
         [0076]    The pit  160  is partitioned into a signal cable space and power supply cable space. The signal cable for exchanging signals between the gantry  121 , the bed  122 , and the console  141  is stored in the signal cable space of the pit  160 . The power supply cable from the power supply device  131  extends through the power supply cable space of the pit  160 , temporarily enters the switchboard  124 , and extends again from the switchboard  124  through the power supply cable space of the pit  160 , thereby supplying power to the gantry  121 , bed  122 , air-conditioning system  123 , console  141 , and devices  143 .  
         [0077]    In this manner, the pit is formed below the floor of the motor vehicle, and stores the signal cable and power supply cable so as to connect devices constituting the X-ray CT apparatus to each other. No portion projects from the floor or wall, which can improve the workability, spatiality, operability, and services. In the conventional X-ray CT apparatus onboard vehicle  1 , wiring pits project from the floor and wall to limit the space, obstruct the work of the medical staff, and restrict installation of various devices. However, the X-ray CT apparatus onboard vehicle  100  is free from these problems.  
         [0078]    As described in detail above, the present invention employs locking mechanisms for relatively heavy movable portions such as a gantry tilt portion, gantry rotating portion, top plate sliding portion, and bed elevating portion. The states of the locking mechanisms are displayed, and traveling of the vehicle is permitted/inhibited, thereby avoiding an accident such as damage caused by traveling in an unlocking state. When locking of the tilt mechanism by the protection means is reliably released, photographing operation by the x-ray CT apparatus is enabled, and when locking is not released, photographing operation is disabled, thus preventing damage to the tilt mechanism caused by forced operation.  
         [0079]    The present invention also employs locking mechanisms for relatively light movable portions such as a keyboard and mouse. The states of the locking mechanisms are displayed to prompt the operator to fix the keyboard and mouse and inform the operator of the possibility of damage caused by a fall. Even if the relatively light movable portions such as the keyboard and mouse are not completely fixed, only these states are notified, and traveling is not inhibited.  
         [0080]    A control function concerning setting of photographing conditions, setting of the gantry tilt angle, and setting of the top plate stroke will be explained with reference to FIGS. 12, 13, and  14 . FIG. 4 is an enlarged view showing the gantry  121  and bed  122  installed in the CT operation room  120 . The through hole  121   a  serving as a photographing port is formed at the center of the gantry  121 , and the object lying on the top plate  122   a  of the bed  122  is fed into the photographing port  121   a  by sliding the top plate  122   a.    
         [0081]    The slide stroke of the top plate  122   a  to the photographing port  121   a  is generally about 1,800 mm at maximum. However, depending on the spatial conditions of the CT operation room  120 , e.g., when a satisfactory distance cannot be ensured between the gantry  121  and the partition wall  120   a  which partitions the CT operation room  120  and power supply room  130 , the slide stroke can be appropriately restricted to, e.g., 1,600 mm at maximum by a scan controller  304  in accordance with the distance.  
         [0082]    The restriction value is set by changing the slide limit value of the top plate  122   a  by, e.g., bed control firmware. If the medical staff erroneously designates a slide stroke larger than the limit value via a top plate moving switch  301  in photographing operation, the scan controller  304  determines the designated slide stroke and displays on a display  305  a warning so as to reset the slide stroke. This limit value is definitely discriminated from the movable limit of the slide mechanism of the top plate  122   a,  and is set shorter than the movable limit on the basis of the spatial conditions of the CT operation room  120 . In this sense, the limit value is defined as an allowable limit with respect to the movable limit of the mechanism.  
         [0083]    The allowable limit is set with respect to the movable limit so as to prevent the top plate  122   a  which slides from interfering with the partition wall  120   a  when the CT operation room  120  is small because the size of the gantry  121  or the like may change depending on the type of motor vehicle or the type of X-ray CT apparatus installed in the CT operation room  120 .  
         [0084]    Although not shown in the gantry  121 , the gantry  121  has the rotating ring to which the X-ray tube and X-ray detector are attached to face each other via the photographing port  121   a.  The gantry  121  further incorporates a driving unit for driving the rotating ring, a tilt mechanism for tilting the gantry  121 , a high-voltage generator for generating a high voltage to be applied to the X-ray tube, and a signal amplifier for amplifying a signal detected by the X-ray detector. The tilt angle of the gantry  121  by the tilt mechanism generally ranges from +30° to −30° (tiltable limit). However, the tilt angle can be properly set to, e.g., +20° to −20° (allowable limit) depending on the spatial conditions of the CT operation room  120 , e.g., when the distance between the gantry  121  and the partition wall  120   a  which partitions the CT operation room  120  and power supply room  130  or the height between the floor and ceiling of the CT operation room  120  cannot be sufficiently ensured in order not to interfere with the ceiling and partition wall  120   a  of the CT operation room  120  even if a different type of gantry  121  is installed in the CT operation room  120 , similar to the bed  122  and top plate  122   a.  The tilt angle is also set by changing the limit tilt angle of the tilt mechanism by, e.g., tilt mechanism control firmware.  
         [0085]    Photographing procedures executed while determining whether the slide stroke of the top plate  122   a  and the tilt angle of the gantry  121  is proper will be described. Various setting operations of the X-ray CT apparatus, e.g., setting of a tube voltage and tube current for setting the conditions of X-rays emitted from the X-ray tube inside the gantry  121 , setting of the slide stroke of the top plate  122   a  for positioning a portion to be photographed to the photographing port  121   a,  and setting of the tilt angle and the number of shots are designated and input to the controller  141   b  by the medical staff by using the switch  301  and switches  302  and  303  such as the keyboard  141   c  and mouse  141   d.    
         [0086]    At this time, the controller  141   b  determines based on the input tube voltage and tube current whether the load does not exceed an allowable limit set lower than the maximum capacity of the power supply device  131  by power consumed by an illumination device, air-conditioning device, and other devices. If the controller  141   b  determines that the load exceeds the allowable limit, it outputs a warning to suspend x-ray exposure. If the medical staff changes the settings and the controller  141   b  determines that the X-ray exposure conditions fall within the allowable limit, X-rays are normally emitted to collect CT data.  
         [0087]    As described above, the X-ray CT apparatus onboard vehicle  100  supplies power to associated equipment such as the X-ray CT apparatus from the power supply device  131  including the mounted power generator, but the power supply capacity is limited. For example, when the power supply capacity of the power supply device  131  is only 75 kVA, a current which can be supplied to the X-ray CT apparatus is 60 kVA because the air-conditioning system  123  and other associated equipment mounted in the X-ray CT apparatus onboard vehicle  100  require about 15 kVA. However, about 75 kVA is necessary for only the X-ray CT apparatus, but cannot be ensured. For this reason, the tube voltage or current of the X-ray tube in X-ray exposure when the X-ray CT apparatus requires the largest power is restricted to a dedicated allowable limit so as not to exceed the power supply capacity.  
         [0088]    When the X-ray exposure condition (tube voltage or current) is set, the power is controlled by calculating a necessary power amount from the set value, and comparing the calculated power amount with an allowable limit obtained by subtracting power necessary for associated equipment from the power supply capacity of the power supply device  131 . If X-rays are emitted under the maximum output condition of a general X-ray CT apparatus, the apparatus may be overloaded. If the overloading state repetitively occurs, this may cause the failure of the power supply device  131 . Moreover, the power supply may stop to cause the malfunction of the computer or delete acquired important image data. These problems can be solved by the above-described control.  
         [0089]    [0089]FIG. 13 is a flow chart showing photographing procedures executed while determining whether the slide stroke of the top plate  122   a  and the tilt angle of the gantry  121  is proper. Every photographing operation using the X-ray CT apparatus, the medical staff operates the keyboard  141   c  (switches  301  and  303 ) to set the slide stroke of the top plate  122   a  as step  1  (ST 1 ) in accordance with the photographing portion. In ST 2 , whether the set stroke falls within a predetermined allowable limit is checked, and if YES in ST 2 , the flow shifts to ST 3  to output a warning that the stroke must be reset. In accordance with the warning, the medical staff returns to ST 1  to reset the slide stroke of the top plate  122   a.  If NO in ST 2 , the flow shifts to ST 4  to drive the top plate  122   a.    
         [0090]    Then, the flow advances to ST 5  to set the tilt angle of the gantry  121 . Whether the tilt angle set in ST 5  falls within a predetermined allowable range is checked in ST 7 . If NO in ST 7 , the flow shifts to step ST 6  to output a warning that the tilt angle must be reset. In accordance with the warning, the medical staff returns to ST 5  to reset the tilt angle. If YES in ST 7 , the flow advances to ST 8  to drive the tilt mechanism, and mechanism setting operation ends.  
         [0091]    [0091]FIG. 14 is a flow chart showing photographing procedures executed while determining whether setting of X-ray exposure conditions (tube voltage and tube current) is proper. X-ray exposure conditions are set in accordance with the photographing portion and the age and obesity of the object. Whether the tube voltage and tube current of the X-ray tube set in step  11  (ST 11 ) fall within an allowable limit set lower than the power supply capacity of the power supply device  131  is determined in ST 12 . If NO in ST 12 , the flow shifts to ST 13  to output a warning that the tube voltage and tube current must be reset. In accordance with this warning, the medical staff returns to ST 11  to reset the tube voltage and tube current. If YES in ST 12 , the flow shifts to ST 14  to permit X-ray exposure.  
         [0092]    (Second Embodiment)  
         [0093]    An embodiment of a medical image information transfer method and apparatus according to the present invention will be described in detail with reference to FIG. 15. As a means for implementing this embodiment, a mobile personal computer called a commercially available notebook type personal computer, or a mobile work station (to be simply referred to as a mobile WS hereinafter) is prepared. A mobile WS  401  incorporates a hard disk having a memory capacity of about 10 GB, and a hard disk can be properly added. The mobile WS  401  can realize a much larger memory capacity than an existing CD-R or 3.5″ magneto-optic disk, and can record necessary medical image information acquired from about 200 objects (i.e., medical image information of 200 samples) in group examination.  
         [0094]    The mobile WS  401  incorporates a DICOM STORAGE SCP (SCP; Service Class Provider) function and DICOM STORAGE SCU (SCU; Service Class User) function as an Ethernet interface and application software in order to enable DICOM communication. DICOM STORAGE SCP defines functions which should be held on a medical image reception side in saving medical image information defined by DICOM. Similarly, DICOM STORAGE SCU defines functions which should be held on a medical image transmission side in saving medical image information.  
         [0095]    A modality device  402  incorporates the DICOM STORAGE SCU function. The mobile WS  401  is set near the modality device  402  and connected to it via a signal line (e.g., Ethernet)  403 . With this arrangement, medical image information acquired by the modality device  402  is transferred to the mobile WS  401  via the signal line  403  and stored in the hard disk of the mobile WS  401 . That is, the mobile WS  401  functions as an image server device for temporarily saving medical image information.  
         [0096]    The mobile WS  401  which temporarily stores medical image information is moved close to an image server device  405  by a proper carrier means  404 . For example, when the mobile WS  401  and modality device  402  are mounted in an examination vehicle (not shown), the medical staff may carry the mobile WS  401  to the installation place of the image server device  405  after the examination vehicle comes back to a hospital as a base, or the carrier person may carry the mobile WS  401  from a group examination place to a predetermined hospital.  
         [0097]    The mobile WS  401  is connected via the signal line  403  to the image server device  405  installed in the predetermined hospital. The medical image information which has been acquired by the modality device  402  and temporarily stored in the mobile WS  401  is transferred by offline to the image server device  405 . Transfer operation from the mobile WS  401  to the image server device  405  may be performed automatically or manually. Also, the image server device  405  must incorporate the DICOM STORAGE SCP function.  
         [0098]    The medical image information transferred to the image server device  405  is displayed on an image diagnostic apparatus (not shown), and diagnosed by a medical specialist. If necessary, the medical image information stored in the image server device  405  can be properly read out.  
         [0099]    According to the second embodiment, the DICOM STORAGE SCU function is requested of the modality device  402 , and the DICOM STORAGE SCP function is requested of the image server device  405 . The mobile WS  401  having both the DICOM STORAGE SCU function and DICOM STORAGE SCP function is interposed between the modality device  402  and the image server device  405 . This can greatly improve connectivity even in the environment where the modality device  402  and image server device  405  cannot be connected by a signal line under physical restrictions.  
         [0100]    The mobile WS  401  incorporates a hard disk having a storage capacity of about 10 GB, so that the storage capacity of medical image information is much larger than a magneto-optic disk or CD-R. One mobile WS  401  can save all pieces of medical image information collected by one-day group examination by temporarily recording pieces of medical image information acquired by group examination objected to many objects, on the mobile WS  401  instead of an information recording medium such as a 3.5″ magneto-optic disk or CD-R.  
         [0101]    As described in detail above, according to the second embodiment, the connectivity between the modality device and the image server device can be greatly improved even in the environment where the modality device and image server device cannot be connected by a signal line under physical restrictions.  
         [0102]    One mobile WS  401  can save all pieces of medical image information acquired by one-day group examination by temporarily recording pieces of medical image information acquired by group examination on the mobile WS  401 . Unlike the prior art, the operator need not frequently exchange information recording media such as 3.5″ magneto-optic disks or CD-Rs, which increases the efficiency and reduces the burden on the operator such as medical staff.  
         [0103]    Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.