301.

Next, in step S304, the radiation dose estimating unit 109 estimates the radiation dose to be irradiated by the radiation generating unit 103. The radiation dose estimating unit 109 can estimate the radiation dose by using the imaging parameter information obtained in step S301, the AEC parameters obtained in step S302, and the target dose and the imaging condition set in step S303 as inputs. The radiation dose to be estimated includes, for example, at least one of dose area product, an absorbed dose, an irradiated dose, an air kerma, and a skin dose. Known methods can be used to estimate the radiation dose. The radiation dose may be estimated by converting from known physical property values by, for example, the Numerical Dose Determination (NDD) method, or may be estimated using a method calculated by, for example, the Monte Carlo method.

If the AEC function is off, the radiation dose estimating unit 109 estimates the radiation dose based on the imaging parameter information and the imaging condition, and outputs it to the output unit 108.

In contrast, if the AEC function is on, the radiation dose estimating unit 109 does not have to estimate the radiation dose. In a case where the radiation dose is not estimated, the radiation dose estimating unit 109 may output to the output unit 108 that the radiation dose is not estimated, or may output nothing. The radiation dose estimating unit 109 may output to the output unit 108 information indicating that the AEC function is on.

On the other hand, the radiation dose estimating unit 109 may estimate the radiation dose and output it to the output unit 108 even if the AEC function is on. In this case, the radiation dose estimating unit 109 can estimate the radiation dose based on the imaging parameter information, the AEC parameter, the target dose, and the imaging condition. In addition to the estimated radiation dose, the radiation dose estimating unit 109 also outputs information indicating that the AEC function is on to the output unit 108.

In step S305, the output unit 108 outputs information on the estimated radiation dose based on the output from the radiation dose estimating unit 109. Specifically, if the estimated radiation dose is output from the radiation dose estimating unit 109, the output unit 108 outputs the estimated radiation dose or a warning about the radiation as the information on the estimated radiation dose.

Further, if it is output from the radiation dose estimating unit 109 that the radiation dose is not estimated, if the information indicating that the AEC function is on is output from the radiation dose estimating unit 109, or if nothing is output from the radiation dose estimating unit 109, the output unit 108 outputs the information indicating that the AEC function is on as the information on the estimated radiation dose. Further, if the estimated radiation dose and the information indicating that the AEC function is on are output from the radiation dose estimating unit 109, the output unit 108 outputs the estimated radiation dose and the information indicating that the AEC function is on as the information on the estimated radiation dose. Thus, the output unit 108 can output the estimated radiation dose to indicate that the estimation accuracy is low.

The output destinations of the output unit 108 can include, for example, the PACS connected to the control PC 201 via the network interface 207 in addition to the display apparatus 205 and the display unit 209. The output unit 108 can control the display of the display apparatus 205 and display unit 209 based on the information on the estimated radiation dose.

An example in which the output unit 108 outputs the information on the estimated radiation dose to the display unit 209 if the AEC function is off will now be described. FIG. 4A to FIG. 4D show an example of a screen displayed on the display unit 209 in this case.

In the example shown in FIG. 4A, in addition to the estimated radiation dose estimated by the radiation dose estimating unit 109, a standard radiation dose (DRL value) determined from the imaging parameter information is displayed. By displaying both of the estimated radiation dose and the DRL value in this manner, the user can easily check whether the radiation dose when the radiation is irradiated under the present conditions exceeds the DRL value without a clinically justifiable reason. Therefore, the user can adjust the radiation dose to an optimal radiation dose before the radiation is irradiated to obtain an image. Thus, the control PC 201 can facilitate appropriate radiation dose management by the user. The DRL value may be determined from the imaging parameter value by the control PC 201.

In addition, the output unit 108 may control the display of the display unit 209 to include an expression to emphasize that the estimated radiation dose exceeds the DRL value in the present imaging condition if the estimated radiation dose output by the radiation dose estimating unit 109 exceeds the DRL value by a certain criterion. In this case, the output unit 108 can, for example, emphasize the display by changing user-identifiable elements such as the color, size, and typeface of letters in any combination. Further, as shown in FIG. 4B, the output unit 108 may cause an icon or expression indicating that the estimated radiation dose exceeds the DRL value to be displayed as the warning about the radiation, and may not cause the DRL value to be displayed directly.

Although FIG. 4A and FIG. 4B show examples of representing the radiation dose by characters, as shown in FIG. 4C, the radiation dose may be represented by elements other than characters, such as a bar and a gauge. In addition, as shown in FIG. 4D, an icon indicating that the estimated radiation dose exceeds the DRL value may be displayed as the warning about the radiation. In this case, an expression on display that attracts the user's attention may be added, for example, by changing the color of the icon and making it flash and display.

Next, an example in which the output unit 108 outputs the information on the estimated radiation dose to the display unit 209 if the AEC function is on will be described. FIG. 5A to FIG. 5D show an example of a screen displayed on the display unit 209 in this case.

In the example shown in FIG. 5A, in a case where the radiation dose estimating unit 109 does not output the estimated radiation dose, expression indicating that the AEC function is on is displayed instead of the estimated radiation dose. This is effective in a case where it is not appropriate to indicate the estimated radiation dose to the user if the AEC function is on.

For example, if the radiation dose in an appropriate range is set as the target dose of the AEC, the AEC controls the stop of the irradiation of radiation. Therefore, the user does not have to consider the relationship between the estimated radiation dose and the DRL value. In addition, since the AEC controls the stop of the irradiation of radiation, the estimation based on an input such as the imaging condition may be incorrect. In this case, by presenting the user with an estimated value that is different from the actual irradiated radiation dose, the user may be forced to change the imaging condition unnecessarily. In such a case, for example, the user may reduce the radiation dose below a radiation dose required for clinical use, and the radiation imaging may be performed using a radiation dose that is less than the radiation dose required for the clinical use, and re-imaging is required, thereby the radiation dose used for the imaging may be increased.

On the other hand, as shown in FIG. 5A, by displaying the expression indicating that the AEC function is on instead of the estimated radiation dose, it is possible to prevent the user from unnecessarily changing the imaging condition and to facilitate the appropriate radiation dose management by the user.

In the example shown in FIG. 5B, in a case where the radiation dose estimating unit 109 outputs the information indicating that the AEC function is on together with the estimated radiation dose, an example of a screen displayed on the display unit 209 is shown. In this case, as shown in FIG. 5B, the output unit 108 may display each of the estimated radiation dose, the target dose of the AEC, and the standard radiation dose (DRL values) to the display unit 209.

By presenting that the DRL value is close to the target dose of the AEC, the user can recognize that the imaging will be controlled using the appropriate radiation dose by performing the imaging according to the target dose of the AEC. Further, by checking the relationship between the target dose of the AEC and the estimated radiation dose, the user can recognize the risk of the lack of the radiation dose caused by stopping the irradiation of radiation before the AEC stops the irradiation of radiation. In addition, the user can recognize the risk of the excess of the radiation dose, such as the amount of unnecessary radiation that will be irradiated if the AEC does not function sufficiently. For example, if the irradiation time in the imaging condition is set long according to the assumption that the AEC will stop the irradiation of radiation, the estimated radiation dose will become large. However, it corresponds to such a risk to set the irradiation time too long against the target dose, and therefore it is preferable to improve such a setting.

FIG. 5C shows an example of display without using characters, but shows an example of display in a different expression from the example shown in FIG. 4C in the case where the AEC function is off. In the example shown in FIG. 5C, an expression indicating that the imaging is controlled by the AEC is shown in the gauge indicating the estimated radiation dose indicates, and even in this expression, the expression indicating that the AEC function is on is presented to the user.

FIG. 5D is an example displaying an icon indicating that the AEC function is on for the user. In this case, the output unit 108 may change or blink the color of the icon to emphasize that the AEC function is on, or may display the icon without emphasizing it because the irradiation of radiation is expected to stop at the target dose of the AEC if the AEC function is on.

FIG. 4A to FIG. 4D show the specific examples of the expression to be displayed by the display unit 209 in the case where the AEC function is off. FIG. 5A to FIG. 5D show the specific examples of the expression to be displayed by the display unit 209 in the case where the AEC function is on. However, the expression to be displayed by the display unit 209 is not limited thereto. In addition, the aspect of the output by the output unit 108 is not limited to that described above, and various changes and variations can be made without departing from the spirit and scope of the present disclosure. For example, the destination of the output by the output unit 108 may be the display apparatus 205 rather than the display unit 209, and the expression to be displayed may be realized by combining any identifiable expression. Furthermore, the output by the output unit 108 may not be limited to a visual expression, and an audio output device such as a buzzer (not shown) may be used to alert the user that the AEC function is on by sound.

Next, in step S306, the radiation controlling unit 105 outputs an irradiation signal to the radiation generating unit 103 upon detecting that the user presses the irradiation switch. Upon receiving the irradiation signal, the radiation generating unit 103 starts the irradiation of radiation. The irradiation switch may be directly connected to the radiation generating apparatus 203.

In step S307, the AEC detecting unit 104 accumulates the arrived dose of radiation and calculates accumulated dose. Thereafter, in step S308, the AEC detecting unit 104 compares the accumulated dose calculated in step S307 with the target dose set in step S303. In step S308, if the AEC detecting unit 104 determines that accumulated dose has not reached the corrected target dose, the process returns to step S307, and the AEC detecting unit 104 continues the calculation of accumulated dose. In this case, the AEC detecting unit 104 outputs a continuation request signal as a control request signal to the radiation controlling unit 105 to continue the irradiation of radiation by the radiation generating unit 103. If the radiation controlling unit 105 receives the continuation request signal from the AEC detecting unit 104, it makes the radiation generating unit 103 continue the irradiation of radiation.

On the other hand, if the AEC detecting unit 104 determines that accumulated dose has reached the target dose in step S308, the process transits to step S309. In step S309, the AEC detecting unit 104 outputs a stop request signal as the control request signal to the radiation controlling unit 105. If the radiation controlling unit 105 receives the stop request signal from the AEC detecting unit 104, the radiation controlling unit 105 transmits an irradiation stop signal to the radiation generating unit 103 to stop the irradiation of radiation.

The calculation of the accumulated dose in step S307 is repeated at a predetermined time interval (predetermined cycle). The end condition of the repetition is that the accumulated dose becomes equal to or greater than the corrected target dose, but when a metal having a high radiation absorption rate or the like is imaged in the area for calculating accumulated dose, the accumulated dose does not readily reach the corrected target dose. In this case, an excessive amount of radiation will be irradiated. Thus, a timeout may be added to the end condition of the repetition to prevent such excessive irradiation of radiation.

In step S310, the radiation controlling unit 105 transmits an image readout signal to the radiation image generating unit 106. Upon receiving the image readout signal from the radiation controlling unit 105, the radiation image generating unit 106 reads the image from the radiation sensor 202, generates a radiation image, and transmits the radiation image to the image processing unit 107.

In step S311, the image processing unit 107 performs image processing based on the set image processing parameters on the radiation image generated by the radiation image generating unit 106.

Finally, in step S312, the output unit 108 outputs the radiation image on which the image processing has been performed by the image processing unit 107. The destinations of the output by the output unit