Patent Document

FIELD OF THE INVENTION 
     The present invention relates to an operation management technique of a mobile-type X-ray apparatus for executing X-ray imaging by making the rounds in hospitals, particularly to a technique for monitoring power consumption amount of batteries provided to a mobile-type X-ray apparatus. 
     DESCRIPTION OF RELATED ART 
     Battery-driven devices are generally provided with the function to detect and display available power supply at the present point (remaining battery power) (for example, refer to Patent Document 1). Mobile-type X-ray apparatuses that are movable for making the rounds in hospitals to execute X-ray imaging also use batteries as a drive source for X-ray irradiation. Thus they also have a function which displays remaining battery power to indicate the timing for exchanging batteries and the remaining time for operating the device. 
     PRIOR ARTS 
     Patent Document 1: Japanese Patent No. 3078286 
     However, since power consumption of a battery is different in each imaging condition, it is difficult to predict whether or not the remaining power of battery is able to complete the entire scheduled imaging by referring only to the remaining battery power. Particularly a mobile-type X-ray apparatus often uses a battery not only as the drive source for X-ray imaging but also as the power source for moving, which makes it more difficult to predict the timing for recharging the battery. This problem sometimes causes the condition that the battery is expended after moving the X-ray apparatus. In order to avoid such situations, an extra amount of battery power needs to be consistently charged up which often incurs waste. 
     The object of the present invention is to provide a technique to support determining if the remaining amount of battery power is enough to execute desired quantity of imaging by using a mobile-type X-ray apparatus driven by a mounted battery, considering the above-mentioned problem. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention, based on the imaging list of the scheduled imaging and the pre-stored power consumption information for each target region, calculates the predictive amount of battery power consumption for completing the entire imaging on the imaging list and displays the calculated amount along with the remaining battery power to an operator. 
     In concrete terms, it provides the mobile-type X-ray apparatus provided with a battery for executing X-ray imaging, comprising: 
     remaining battery power detecting means configured to detect remaining power of a battery; 
     predictive power consumption calculating means configured to calculate predictive battery power consumption based on an imaging list for making the rounds; and 
     display means configured to display the remaining power and the predictive battery power consumption. 
     In accordance with the present invention, it is possible to easily determine if the entire planned imaging can be executed by a mobile-type X-ray apparatus using a battery as its drive source. 
    
    
     
       BRIEF DESCRIPTION OF THE DIAGRAMS 
         FIG. 1  is a block diagram of a substantial part in the mobile-type X-ray apparatus related to an embodiment of the present embodiment. 
         FIG. 2  is a functional block diagram of a power consumption controller in an embodiment of the present embodiment. 
         FIG. 3  is a hardware block diagram of the power consumption controller in an embodiment of the present invention. 
         FIG. 4  is for explaining an imaging list in an embodiment of the present invention. 
         FIG. 5  is for explaining a power consumption table by target region related to an embodiment of the present invention. 
         FIG. 6  is for explaining an example of a display screen related to an embodiment of the present invention. 
         FIG. 7  is a flowchart showing a process for displaying predictive battery power consumption related to an embodiment of the present invention. 
         FIG. 8  is a functional block diagram for correcting the power consumption controller related to an embodiment of the present invention. 
         FIG. 9  is a functional block diagram for updating the moving power consumption in the power consumption controller related to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment related to the present invention will be described below referring to the attached diagrams. In all the diagrams, the same function parts are represented by the same reference numerals, and the duplicative description thereof is omitted. 
       FIG. 1  is a block diagram of a substantial part of mobile-type X-ray apparatus  100  in the present embodiment. Mobile-type X-ray apparatus  100  of the present embodiment comprises motor- or manually-driven mobile carriage  106 , wheels  107 , rechargeable battery  108 , X-ray generator  102  for irradiating X-rays, main body  101  for supporting the X-ray generator via an arm, imaging controller  109  for controlling imaging, input unit  103 , display unit  104  and power consumption controller  105 , as shown in the diagram. 
     In the present embodiment, the predictive power consumption of rechargeable battery  108  is calculated in power consumption controller  105 .  FIG. 2  is a functional block diagram of power consumption controller  105  of the present embodiment. Power consumption controller  105  comprises imaging list controller  201 , remaining battery power detecting unit  204 , predictive battery power consumption calculating unit  205  and display unit  206 , calculates predictive battery power consumption  250  using imaging list  210 , power consumption table by target region  220  and moving power consumption  230  and detects remaining battery power  240 . 
     As shown in  FIG. 3 , power consumption controller  105  comprises central processing unit (CPU)  301  for controlling operation of the respective components, RAM  302  for temporarily storing data etc. for CPU  301  to execute processing, ROM  303  for storing various data or control program, display unit  304  for displaying the processing result, and input device  305  for receiving the input of various commands. 
     The above-described respective functions are achieved by loading the control program stored in ROM  303  to RAM  302  to be executed by CPU  301 . Display device  304  and input device  305  of power consumption controller  105  may be configured to be used also as display unit  104  and input unit  103  of mobile-type X-ray apparatus  100 . Also, mobile-type X-ray apparatus  100  may comprise the device having configuration connectable to a network in hospitals (for example, a CR device or FPD device). 
     Imaging list controller  201  controls imaging list  210  which is inputted via input device  305  and stored in ROM  303 . Imaging list  210  contains the list of imaging examinations planned for one round, and a target region to be imaged for each patient and the number of imaging times are registered.  FIG. 4  is for explaining imaging list  210 . On the imaging list  210 , the information for specifying the imaging order (order information)  211 , the information for specifying the patient (patient information)  212 , the information for specifying the imaging target region (target region information)  213  and the number of imaging times  214  are registered as imaging data for each imaging as shown in  FIG. 4 . In patient information  212 , patient ID  212   a  for uniquely specifying the respective patients is registered. Also, imaging list controller  201  notifies predictive battery power consumption calculating unit  205  when imaging list  210  is newly inputted or updated. In the case that mobile-type X-ray apparatus  100  has a device having configuration connectable to a network in hospitals, imaging list  210  may be configured to be inputted or updated via the device. Further, imaging list  210  may be comprised in the foresaid device. 
     Imaging list controller  210 , upon receiving the notification from imaging controller  106  that a certain imaging is completed, deletes the imaging data of the completed imaging and updates imaging list  210 . At this time, imaging order information  211  of the imaging data after the deleted imaging is moved forward one by one. Also, when new imaging is added, imaging data added in the assigned imaging order is inserted, and imaging order information  211  of the imaging data after the inserted imaging is to be moved down for the number of the inserted imaging data. Such control process is to be continued, for example until the command to end the rounds is received via input device  305 . 
     In power consumption table  220  for each region, the power consumption according to the imaging target region is registered.  FIG. 5  is for explaining power consumption table  220  for each target region. In power consumption table  220  by target region, an available power consumption of mobile-type X-ray apparatus  100  to execute imaging for each imaging region  221  (battery power consumption information)  222  is stored. As for battery consumption information  222 , for example tube voltage (kV) and tube current time integration (mAs) to be required upon imaging each target region are registered. Also, power consumption table  220  by target region is stored in ROM  303  in advance. In the case that mobile-type X-ray apparatus  100  comprises the device connectable to a network in a hospital, power consumption table  220  may be stored outside of mobile-type X-ray apparatus  100 . 
     The electric energy to be consumed upon moving among patients (moving power consumption) is controlled as moving power consumption  230 . The pre-set values are registered in ROM  303  as moving power consumption  230 . 
     Remaining battery power detecting unit  204  detects the sufficient electric energy which rechargeable battery  108  can supply being set off by predetermined time intervals or occurrence of a predetermined event, stores the detected energy in ROM  303  as remaining battery power  240 , and notifies it to display processor  206 . For detection of remaining battery amount  240 , a commonly known method for detecting remaining battery amount is to be used. For example, sufficient power supply amount is calculated by detecting the output current from rechargeable battery  108 . 
     Predictive battery power consumption calculating unit  205 , when receiving the command from the user or the notification from imaging list controller  201  that imaging list  210  is updated, calculates the power consumption for executing the entire imaging registered in imaging list  210  as predictive battery power consumption  250 . Predictive battery power consumption  250  is a sum of the predictive imaging power consumption to be consumed in imaging itself and predictive moving power consumption to be consumed in moving mobile-type X-ray apparatus  100  among imaging examinations. 
     For calculating predictive imaging power consumption, power consumption for the number of scanning times for each patient or target region is calculated and summed, using power consumption information  222  stored in power consumption table by target region  220  corresponding to target  221  which accords with target region information  213  on imaging list  210 . Also, predictive moving power consumption is to be obtained by multiplying the number of patients registered in imaging list  210  by moving power consumption  230 . The number of patients is to be counted using patient ID  212   a  in imaging list  210 . Predictive battery power consumption calculating unit  205  notifies the calculated predictive battery power consumption  250  to display processing unit  206 . 
     Display processing unit  206  generates display data for displaying remaining battery power  240  and predictive battery power consumption  250  on display unit  304 .  FIG. 6  is for explaining an example of display screen  600  formed by display data. Display screen  600  comprises first display section  601  and second display section  602 . Remaining battery power  240  is displayed on first display section  601  and predictive battery power consumption  250  is displayed on second display section  602  respectively. The display of remaining battery power  240  and predictive battery power consumption  250  are updated respectively upon receiving the notification. These figures are displayed, for example on percentage (0%˜100%) with respect to the electric energy in the case that rechargeable battery  108  is recharged 100%. 
     Display device  304  may comprise command button  603  for receiving the command to switch the content of display. Display processing unit  206  receives the command to change the display via command button  603  and changes, for example remaining battery amount  240  and predictive battery power consumption  250  from the above-mentioned numeric display to a chart display. The method for displaying remaining battery amount  240  and predictive battery power consumption  250  are not limited thereto. Any display pattern that is easy for the user to capture the amount values visually may be used such as graph display, meter display or digital display. 
     Next, predictive battery power consumption  250  of the present embodiment is calculated and displayed. The processing flow for displaying the predictive battery power consumption by power consumption controller  105  will be described. Here, the case that starts the process on the basis of the registration of imaging list  210  will be exemplified.  FIG. 7  is a flowchart showing the display process of predictive the battery power consumption. Here, the case that calculates predictive battery power consumption  250  for every update of imaging list  210  will be exemplified. It also may be configured such that the above-mentioned calculation is executed only when the command from the user is received. Also, remaining battery power  240  is to be detected separately at predetermined intervals. 
     Upon receiving the input of an imaging list via input device  305  (step  701 ), imaging list controller  201  registers imaging list  210  in ROM  303  (step  702 ), and notifies the list to predictive battery power consumption calculating unit  205 . Upon receiving the notification, predictive battery power consumption calculating unit  205  calculates predictive battery power consumption  250  referring to imaging list  210  (step  703 ). Then it notifies the calculation result to display processing unit  206 . Display processing unit  206  generates display data using the most updated remaining battery power  240  stored in remaining battery detecting unit  204  and the notified predictive battery power consumption  250  (step  704 ), and displays the generated data on display device  304  (step  705 ). After that, imaging list controller  201  monitors if imaging list  210  is updated, and also monitors the command from the user to end the rounds at predetermined timings (steps  706  and  707 ). When the list is updated the process returns to step  702 , and when the command to end the rounds is received the process is to be ended. 
     Also, in the case that mobile-type X-ray apparatus  100  is the kind in which imaging list is stored in advance such as a CR device or FPD device, for example power consumption controller  105  executes the above-mentioned step  703  and subsequent steps thereof being set off by receiving of the command from the user to start calculating the predictive battery power consumption via input device  305 . 
     As mentioned above, in accordance with the present embodiment, not only the remaining battery power at the present time but also the predictive battery power consumption planned to be consumed in the subsequent imaging examinations is displayed on the display unit. The approximate estimate of the power consumption to be consumed by moving of mobile-type X-ray apparatus  100  in rounds is also included in the predictive battery power consumption. Therefore, it is possible to acquire the predictive battery power consumption calculated with high accuracy. Also, the user can easily determine whether to execute the imaging registered in the imaging list or to recharge the battery by comparing the remaining battery power and the predictive battery power consumption. 
     Also, the predictive battery power consumption is updated in accordance with the update of the imaging list. Therefore, even in the situation such as addition of imaging, requirement for re-imaging or emergency imaging occurs, it is possible to identify accurate predictive battery power consumption which leads to quick response to the change of examination plan. 
     While the above-described embodiment calculates and displays predictive battery power consumption  250  of along with remaining battery power  240 , the display content is not limited thereto. For example, it may be configured to display the predictive power supply that rechargeable battery  108  can supply (predictive remaining battery amount) after executing the entire imaging registered in imaging list  210 . Predictive remaining battery power is calculated, after calculating predictive battery power consumption  250  by predictive battery power consumption calculating unit  205 , by subtracting predictive battery power consumption  250  from remaining battery power  240  at the present time point. Then display processing unit  206  displays the predictive remaining battery power on display device  304  along with remaining battery power  240 . Also, when the predictive battery power becomes minus, the information indicating “shortage” may be displayed. 
     Also, it may be configured to display the information indicating up to which point in imaging list  210  can be imaged (available imaging list) with remaining battery power  240  at the present time. In this case, predictive battery power consumption calculating unit  205  repeats subtracting from remaining battery power  240  the battery power consumption necessary for executing the imaging and subtracting the moving power consumption each time the patient information is changed in the order of imaging list  210 , until the result ends up as minus. When the result ends up as minus, predictive battery power consumption calculating unit  205  determines that the imaging can be executed until the imaging data just before the power runs out and notifies, for example order number information  211  of the imaging data just before the power runs out to display processing unit  206 . In the case that the result does not reach minus when the entire list in imaging list  210  is processed, the information indicating that the entire imaging can be executed is notified to display processing unit  206 . Display processing unit  206  displays the available imaging list along with remaining battery power  240 . 
     As for the display pattern of the available imaging list, for example the entire imaging data available to be imaged from among imaging list  210  may be displayed, the imaging data determined as available to be imaged may be displayed in an identifiable manner, or the maximum number from among order number information  211  of the imaging data determined as available to be imaged may be displayed. 
     Also, the number of image pieces available to be imaged for each target region (the available imaging pieces by target region) may be calculated and displayed using not the predictive battery power consumption based on imaging list  210  but by remaining battery power  240 . Predictive battery power consumption calculating unit  205  calculates the number of available imaging pieces for each target region using power consumption information  222  for each target region stored in power consumption table  220  for each target region. Display processing unit  206  displays the number of available imaging pieces for each target region on display device  304 . The electric consumption energy to be consumed in imaging is different by each target region. Therefore, obtaining the number of available imaging pieces for each target region facilitates the user to easily change the plan for the rounds by using the obtained information as a guide. 
     Mobile-type X-ray apparatus  100  of the present embodiment may have the configuration capable of calculating and displaying one or more items from among predictive battery power consumption  250 , predictive remaining battery power, available imaging list and available number of imaging pieces for each region. Also, it may have the configuration that enables the user to select which items are to be displayed. By having the capability to display a plurality of items, the user can identify whether or not he/she can execute the imaging on an imaging list more easily. 
     Further, it may be configured that a predictive remaining battery power, available imaging list and available number of imaging pieces for each region are calculated and displayed also when remaining battery power  240  changes more than a predetermined value from the previous calculation, in addition to when receiving a command from the user or imaging list  210  is updated. This configuration is provided with the function to store the remaining battery power at the time of calculation, and to compare the remaining battery power at the time of update with the stored remaining battery power. In this manner, when there is a significant change in the remaining battery power, for example in the cases that no imaging is executed while mobile-type X-ray apparatus  100  is running or an unexpected long distance movement is required, more accurate calculation result can be obtained. 
     Further, the present embodiment may be configured capable of executing various corrections upon calculation of the above-mentioned various items by predictive battery power consumption calculating unit  205 . Also, the corrections to be considered may be selected by a user. Here, the case will be exemplified that correction can be made on operating time, temperature at the environment of usage, degradation, and device type of rechargeable battery  108 . The additional configuration to power consumption controller  105  required to execute these corrections is shown in  FIG. 8 . 
     Power consumption controller  105  comprises correcting selection receiving unit  810 , temperature measuring unit  802  and temperature correcting unit  820  for making correction due to the temperature at the environment of usage, degradation degree detecting unit  803  and degradation degree correcting unit  830  for making correction due to degradation of battery, device type input unit  804  and device type correcting unit  840  for making correction due to the type of the device being used, and time measuring unit  805  and time correcting unit  850  for making correction due to operating time (passage of operating time). Correcting selection receiving unit  810  gives command to the respective units via input device  305  to execute only the selected correction. 
     Generally, available energy capacity of a battery changes according to the temperature at the environment of usage. When the temperature drops, available energy capacity decreases and remaining battery power  240  also decreases. In order to measure the temperature of rechargeable battery  108  at the environment of usage, temperature measuring device  802  is placed in the vicinity of rechargeable battery  108 . As for temperature measuring device  802 , for example a thermistor is used. When the command to consider correction due to temperature is received by correcting selection receiving unit  810 , temperature correcting unit  820  calculates the correction value for correcting remaining battery power  240  using the temperature measured by temperature measuring device  802 . The correction value is calculated using correlative information between the temperature and the change in battery capacity and correlative information between the battery capacity and the available electric power that are stored in advance. Then the correction value is notified to remaining battery power detecting unit  204 . Remaining battery power detecting unit  204  corrects the detected remaining battery power  240  detected using the correction value. 
     Also, generally a battery deteriorates as being used. In accordance with the degradation of battery, the battery power consumption also varies. When the command to consider the correction due to degradation of battery is received by correcting selection receiving unit  810 , degradation detecting unit  803  detects the voltage or current at the time of high-load usage such as during imaging or moving. Degradation degree detecting unit  830  compares the power consumption calculated from the detected voltage or current and the pre-stored power consumption at the time of high-load condition, determines the degradation degree of rechargeable battery  108 , calculates the correction value for correcting the remaining battery power, and notifies the calculated power to remaining battery power detecting unit  204 . Remaining battery power detecting unit  204  corrects the remaining battery power  240  using the correction value. 
     In the case that mobile-type X-ray apparatus  100  has the function besides the imaging function such as for connecting to a network in a hospital, for example a CR device or FPD device, the electric power consumption increases for the amount to operate those functions. When the command to consider the correction due to the type of device is received by correcting selection receiving unit  810 , type input unit  804  receives the information to specify the type of device via input device  305 . Type correcting unit  840  stores the information to specify the increase of electric power consumption according to the respective devices, and extracts the electric power consumption (increasing portion) according to the received type of device. Then it notifies the extracted increasing portion of the electric power consumption to predictive battery power consumption calculating unit  205 . Predictive battery power consumption calculating unit  205  adds the received increasing portion to the calculated predictive battery power consumption  250  to make it zero. 
     Type input unit  804  may be configured to input not only the type of device but also the information for specifying a user. In this case, type correcting unit  840  stores the variation portion of the electric power consumption according to a user, and notifies the obtained increasing portion to predictive battery power consumption calculating unit  205 . 
     When mobile-type X-ray apparatus  100  is running without imaging for a long period of time, the output of rechargeable battery  108  decreases. However, predictive battery power consumption calculating unit  205  does not execute the process unless imaging list  210  is updated or the command from a user is received. Therefore, when one kind of calculation is executed from among the calculations for predictive remaining battery power, available imaging list or the number of available imaging piece for each region, there is a possibility that the accuracy of these calculation results is lowered. When the command to consider the correction due to passage of time is received by correcting selection receiving unit  810 , time measuring unit  805  measures the passage of time from the previous calculation executed by predictive battery power consumption calculating unit  205 . Time correcting unit  850  monitors the measurement by time measuring unit  805 , and when determination is made that more time has passed than a predetermined time, gives the command to predictive battery power consumption calculating unit  205  to execute re-calculation. Then it makes the correction by replacing predictive battery consumption  250  with the obtained result. By employing the above-described correction, it is possible to reflect the lowering of a battery output on a timely basis in the case that the imaging is not executed for a long period of time while mobile-type X-ray apparatus  100  is running. 
     As described above, by providing with the configuration capable of executing various types of correction, predictive battery power consumption can be presented to a user with a higher accuracy, and the timing for recharging a battery can also be determined more accurately. 
     The present embodiment also may be configured as capable of selecting whether or not to consider the predictive moving power consumption. When the command to consider the predictive moving power consumption is received via input device  305  is selected, power consumption controller  105  causes predictive battery power consumption calculating unit  205  to calculate also the predictive moving power consumption. Also, moving power consumption  230  does not have to be provided. In this case, predictive battery power consumption calculating unit  205  calculates only the predictive power consumption for imaging as the predictive battery power consumption. For example, in the case that mobile-type X-ray apparatus  100  is mainly moved manually, it is possible to obtain sufficiently accurate information with such easy processing. 
     Also, the present embodiment may be configured capable of correcting moving power consumption  230  according to the used facility (hospital). This is because the moving distance per patient differs largely depending on the size of the facility. 
     Also, the present embodiment may be configured as capable of updating moving power consumption  230 . That is, the moving power consumption is calculated from the actual moving power consumption and the calculated power consumption is to be replaced with the newest calculation result at each round. 
     In order to achieve the above-mentioned function, electric consumption controller  105  comprises moving power consumption controller  203  that updates moving power consumption  230  as shown in  FIG. 9(   a ). Moving power consumption  203  comprises moving power consumption measuring unit  901  for measuring the actual power consumption at the time of moving from the variation etc. of the remaining battery power, actual measurement database  902  for storing the actual moving power consumption wherein the measured power consumption is divided by the number of patients who received imaging examination for a portion of the predetermined previous numbers of measuring times, and first moving power consumption calculating unit  903  for calculating the average of the stored actual moving power consumption as the updated moving power consumption  230 . 
     Also, when the power consumption according to the unit moving distance is clarified, the present embodiment may be configured to update the moving power consumption based on the average moving distance for making one round. In order to achieve the above-mentioned configuration, moving power consumption controller  203  is to be placed in the vicinity of wheel  107  of moving carriage  106 , and comprises moving distance detecting unit  911  for detecting the moving distance from the number of rotations of wheel  107 , moving distance database  912  for storing the moving distance detected by moving distance detecting unit  911  for the predetermined previous numbers of imaging times, and second moving power consumption calculating unit  913  for calculating moving power consumption  230  by calculating the average of the moving distances stored in moving distance database  912 , multiplying the calculated average value by the electric power consumption according to the above-mentioned unit moving distance and dividing the multiplied value by the number of patients who received an imaging examination in the rounds, as shown in  FIG. 9(   b ). 
     As described above, by providing the configuration capable of updating moving power consumption  230 , accuracy in calculating the predictive moving power consumption can be further improved. 
     Further, while the above-described embodiment is configured to update the content to be displayed on display device  304  according to the command from command button  603 , the present embodiment is not limited thereto. For example, in the case that display device  304  is used also as display unit  104  for setting and displaying the imaging condition of mobile-type X-ray apparatus  100 , it may be configured to display the information related to rechargeable battery  108  such as remaining battery power  240  and predictive battery power consumption  250  while the apparatus is moving and to execute usual display while the apparatus is not moving. 
     In this case, for example the present embodiment comprises a brake-release detecting unit for detecting release of a break and a display data switching unit, and switches the display data on display unit  104  when the break-release detecting unit detects that the break is released. 
     By comprising the above-described configuration, it is possible to obtain the necessary information at necessary situations with simple configuration. 
     Description Of Reference Numerals 
       100 : mobile-type X-ray apparatus,  101 : main body,  102 : X-ray generator,  103 : input unit,  104 : display unit,  105 : electric consumption controller,  106 : moving carriage,  107 : wheel,  108 : rechargeable battery,  109 : imaging controller,  201 : imaging list controller,  204 : remaining battery power detecting unit,  205 : predictive battery power consumption calculating unit,  206 : display processing unit,  210 : imaging list,  211 : order information,  212 : patient information,  212   a : patient ID,  213 : region information,  214 : number of imaging pieces,  220 : power consumption table for each region,  221 : region,  222 : power consumption information,  230 : moving power consumption,  240 : remaining battery power,  250 : predictive battery power consumption,  301 : CPU,  302 : RAM,  303 : ROM,  304 : display device,  305 : input device,  600 : display screen,  601 : first display section,  602 : second display section,  603 : command button,  802 : temperature measuring unit,  803 : degradation degree detecting unit,  804 : type input unit,  805 : time measuring unit,  810 : correcting selection receiving unit,  820 : temperature correcting unit,  830 : degradation degree correcting unit,  840 : type correcting unit,  850 : time correcting unit,  901 : moving power consumption measuring unit,  902 : actual measurement database,  903 : first moving power consumption calculating unit,  911 : moving distance detecting unit,  912 : moving distance database,  913 : second moving power consumption calculating unit

Technology Category: 1