JP4281951B2 - Optical scanning method and apparatus - Google Patents

Description

  The present invention scans the reading light with respect to a radiographic image recording medium that receives radiation irradiation carrying a radiographic image, records the radiographic image, and scans with the reading light to read out a signal corresponding to the radiographic image. The present invention relates to an optical scanning method and apparatus.

  2. Description of the Related Art Conventionally, in the medical field and the like, various radiological image recording media that record a radiographic image related to a subject by receiving radiation transmitted through the subject have been proposed and put into practical use.

  Examples of the radiation image recording medium as described above include a radiation image detector using a semiconductor material that generates a charge when irradiated with radiation, or accumulates the radiation energy when irradiated with radiation, and then is exhausted when irradiated with reading light. Examples include a stimulable phosphor sheet that uses a stimulable phosphor that emits light.

  When a radiographic image is read from the radiographic image recording medium as described above as an electrical signal, a reading light source that emits line-shaped reading light is used from the viewpoint of speeding up the reading, and the reading light source has its long length. Reading light is scanned by being moved in a direction substantially perpendicular to the vertical direction (see Patent Document 1).

  Further, from the viewpoint of downsizing of the apparatus, there has been proposed that both the above-described radiation image recording medium and a reading light scanning apparatus having a reading light source are installed in a cassette. If the cassette as described above is used, it is possible to immediately read the radiographic image after recording the radiographic image in the radiographic imaging device. Then, the read radiographic image can be observed, and the radiographic image can be recorded immediately under different imaging conditions.

Japanese Unexamined Patent Publication No. 2000-105297

  However, for example, in a breast X-ray imaging apparatus, imaging is performed by changing the direction of the cassette in various directions depending on imaging conditions, so the moving direction of the reading light source is not necessarily horizontal, and the horizontal direction is In some cases, the reading light source is moved at an inclined angle.

  Therefore, for example, in the case where the reading light source is moved by a motor, if the driving current of the motor is adjusted to the size required when the reading light source moves in the horizontal direction, the moving direction of the reading light source is For example, in the case of the vertically rising direction, the load on the motor increases due to the influence of gravity, so that the drive current is insufficient and the reading light source cannot be moved stably, and the read radiation image Image quality will be degraded. On the other hand, in order to avoid the shortage of the drive current as described above, the drive current when the reading light source moves in the vertical ascending direction is always flowed. The moving direction of the reading light source is the horizontal direction or the descending direction. In this case, an over torque is generated immediately after the reading light source starts to move, and the reading light source cannot be stably moved, resulting in deterioration of the image quality of the read radiation image.

  In order to avoid the above problems, the weight of the reading light source is reduced, or a motor having a motor rating so large that the load due to the weight of the reading light source does not affect the entire driving load. However, the above-described reading light source and motor are very expensive and increase the cost.

  In addition, some radiographic imaging apparatuses scan scanning light by moving the radiographic image recording medium side while the position of the reading light source is fixed. As in the case where the moving direction of the radiographic image is changed, when the moving direction of the radiographic image recording medium is changed, the radiographic image recording medium cannot be stably moved, and the image quality of the read radiographic image is deteriorated. You may be invited.

  In view of the above circumstances, the present invention provides an optical scanning method and apparatus for scanning reading light on the radiation image recording medium as described above, even when the moving direction of the reading light source or the radiation image recording medium changes. It is an object of the present invention to provide an optical scanning method and apparatus capable of stably moving a reading light source.

  The optical scanning method of the present invention records a radiographic image by receiving radiation carrying a radiographic image, and scans a radiographic image recording medium scanned by reading light and reading out a signal corresponding to the radiographic image by a scanning unit. Light that scans the reading light by moving at least one of the reading light source that emits the reading light and the radiation image recording medium relatively in a direction substantially parallel to the reading light scanning surface In the scanning method, the amount of inclination of the reading light source or the radiation image recording medium in the moving direction at the time of scanning of the reading light is detected, and the driving force of the scanning means is changed based on the detected amount of inclination.

  The optical scanning device of the present invention records a radiographic image upon irradiation with radiation carrying a radiographic image, and scans a radiographic image recording medium scanned by reading light and reading out a signal corresponding to the radiographic image by a scanning unit. Light that scans the reading light by moving at least one of the reading light source that emits the reading light and the radiation image recording medium relatively in a direction substantially parallel to the reading light scanning surface In the scanning device, an inclination amount detecting means for detecting an inclination amount in the moving direction of the reading light source or the radiation image recording medium during scanning of the reading light, and a driving force of the scanning means based on the inclination amount detected by the inclination amount detecting means And a driving force changing means for changing.

  In the above optical scanning device, the radiographic image is stored in a cassette provided separately from the radiographic image recording device, which is loaded in the radiographic image recording device that records the radiographic image on the radiographic image recording medium. It can be installed together with the recording medium, and the inclination amount detecting means can be provided in the cassette.

  Further, the tilt amount detecting means can be provided in the loading part of the radiographic image recording medium of the radiographic image recording apparatus for recording the radiographic image on the radiographic image recording medium.

  Further, the tilt amount detection means can obtain information on the tilt amount from a radiographic image recording apparatus that records a radiographic image on a radiographic image recording medium.

  Further, the scanning means performs a blank scan in which the reading light source is moved relatively in a direction substantially parallel to the scanning surface without emitting the reading light from the reading light source before scanning the reading light, and the amount of inclination The detecting means can detect the amount of inclination based on the movement speed fluctuation of the reading light source or the radiation image recording medium in the idle scanning.

  Here, the “inclination amount in the moving direction of the reading light source or the radiographic image recording medium” means, for example, an inclination amount with respect to the horizontal direction in the moving direction of the reading light source or the radiographic image recording medium. For example, a predetermined direction different from the horizontal direction on the vertical plane including the moving direction of the reading light source or the radiation image recording medium may be used as a reference.

  The above-mentioned “changing the driving force of the scanning means” means that, for example, when the scanning means moves the reading light source or the radiation image recording medium by motor driving, the driving current flowing through the motor Is to change. Further, when the scanning means moves only the reading light source, it means changing the driving force for moving the reading light source, and when the scanning means moves only the radiation image recording medium. Means that the driving force for moving the radiation image recording medium is changed, and when the scanning means moves both the reading light source and the radiation image recording medium, the reading light source and the radiation image recording medium are moved. This means changing the driving force.

  In addition, the “information about the tilt amount” indicates, for example, an imaging menu indicating an imaging region and an imaging purpose specified in the radiographic image recording apparatus, and a rotation angle of an arm unit loaded with the radiographic image recording medium. Any information may be used as long as the information directly or indirectly indicates the amount of inclination in the moving direction of the reading light source or the radiation image recording medium.

  According to the optical scanning method and apparatus of the present invention, the amount of inclination in the moving direction of the reading light source or the radiation image recording medium during scanning of the reading light is detected, and the driving force of the scanning means is determined based on the detected amount of inclination. Since the change is made, the reading light source or the radiation image recording medium can be stably moved without incurring an increase in cost due to the use of an expensive reading light source or motor.

  In the above optical scanning device, when the scanning means is installed in the cassette together with the radiation image recording medium, and the inclination amount detecting means is provided in the cassette, the inclination of the cassette is determined by the reading light source or the radiation image. It can be detected as the amount of inclination in the moving direction of the recording medium, and an appropriate amount of inclination can be obtained. Further, even when the tilt amount detecting means is provided in the loading portion of the radiographic image recording medium of the radiographic image recording apparatus, the tilt of the loading portion is detected as the tilt amount in the moving direction of the reading light source or the radiographic image recording medium. Therefore, an appropriate amount of inclination can be obtained.

  Further, when the tilt amount detection means obtains information about the tilt amount from the radiation image recording apparatus, the scanning means scans the reading light source without emitting the reading light from the reading light source before scanning the reading light. It is assumed that the sky scanning is performed relatively moving in a direction substantially parallel to the surface, and the inclination amount detecting means detects the inclination amount based on the moving speed fluctuation of the reading light source or the radiation image recording medium in the empty scanning. In this case, it is possible to detect the amount of tilt without newly providing a tilt sensor or the like.

  Hereinafter, an embodiment of an optical scanning apparatus that performs an optical scanning method of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a mammogram apparatus using an embodiment of the optical scanning apparatus of the present invention.

  As shown in FIG. 1, the breast X-ray imaging apparatus includes an imaging apparatus main body 1 and a cassette 2 loaded in the imaging apparatus main body 1.

  The imaging apparatus main body 1 includes an imaging table 10, an arm unit 12 installed on the imaging table 10, and a cassette loading unit 14 installed on the arm unit 12.

  The arm portion 12 rotates in the direction of arrow A about the joint portion 14a with the imaging table 10 as an axis. The arm unit 12 rotates by itself and also rotates the cassette loading unit 14 in the arrow A direction. A radiation source is built in the radiation emitting unit 12a which is a part of the arm unit 12. The radiation emitted from the radiation emitting unit 12 a is applied to the cassette loading unit 14, and is applied to the radiation image detector 22 in the cassette 2 loaded in the cassette loading unit 14. Note that X-ray imaging by the breast X-ray imaging apparatus is performed in a state where the subject is positioned between the radiation emitting unit 12 a of the arm unit 12 and the cassette loading unit 14. The X-ray imaging is performed in a state where the arm unit 12 rotates according to the X-ray imaging purpose and the arm unit 12 is inclined at various angles.

  FIG. 2 is a schematic configuration diagram of the cassette 2 loaded in the cassette loading unit 14 of the photographing apparatus main body 1. As shown in FIG. 2, the cassette 2 has a rectangular parallelepiped shape, and includes a housing 20 made of a material that transmits radiation and blocks light, a radiation image detector 22 installed in the housing 20, and radiation. It comprises a reading light scanning device 24 that irradiates and scans the image detector 22 with reading light. In FIG. 2, a part of the housing 20 is omitted for explaining the inside of the cassette. Moreover, the cassette 2 shown in FIG. 2 is a state in which the cassette 2 shown in FIG. 1 is turned over, and radiation is irradiated from the lower surface.

  The reading light scanning device 24 emits linear reading light toward the radiation image detector 22, and the reading light source unit 25 is in a direction substantially parallel to the reading light scanning surface of the radiation image detector 22. A reading light scanning unit 26 that scans the reading light by moving it in the direction of arrow Y, and a driving force changing unit 27 that changes the driving force of the reading light scanning unit 26 are provided.

  The reading light scanning unit 26 is rotated by the motor unit 28, the motor unit 28, and thereby the belt 29 is rotated by the screw unit 29a and the screw unit 29a that rotate the fitted gear 29b in the arrow B direction. The gear 29b that moves the portion 29c in the arrow Y direction, the belt 29c that moves the connected reading light source portion 25 in the arrow Y direction, and the reading light source portion 25 slide while being moved in the arrow Y direction by the gear 29b. A support portion 29 d that is installed so as to support the reading light source portion 25 is provided.

  Further, the reading light scanning device 24 detects the amount of inclination of the cassette 2, that is, the amount of inclination of the reading light source unit 25 in the moving direction when the arm unit 12 rotates while the cassette 2 is loaded in the cassette loading unit 14. An inclination sensor 30 is provided. Then, the amount of inclination detected by the inclination sensor 30 is output to the driving force changing means 27, and the driving force changing means 27 determines the driving force of the reading light source unit 25 based on the inputted amount of inclination, and the driving force. The operation of the motor unit 28 is controlled based on the above. The motor unit 28 in the present embodiment is a servo motor, and the driving force change means 27 performs PID control of the servo motor based on the driving force. The reading light scanning device 24 includes an encoder sensor 21a and a linear encoder 21b for performing PID control by the servo motor.

  Further, as the inclination sensor 30, for example, as shown in FIG. 3, a metal ball 32 is enclosed in a cylinder having an electrode 31 divided in the circumferential direction on the inner surface, and the metal ball 32 provides electrical conduction. What detects the amount of inclination by detecting a certain electrode may be used. Further, instead of the metal ball of the tilt sensor 30, a mercury sealed one may be used. In addition, the tilt sensor is not limited to the above-described tilt sensor, and any tilt sensor may be used. For example, the weighted pointer is fixed to the rotating shaft, and the pointer is always vertical. A detector that directly detects the rotation angle of the rotating shaft or detects the rotation angle as an amount of inclination by electrically detecting the deformation of a mechanical member connected to the rotating shaft, or a detector pointer section instead of the above weight You may make it utilize what enclosed the liquid and used the float.

  Further, as shown in FIG. 4, the radiation image detector 22 receives the first electrode layer 33 that transmits the radiation L1 carrying the radiation image and the irradiation of the radiation L1 that transmits the first electrode layer 33. The recording photoconductive layer 34 that generates charges, the charge that acts as an insulator for the charges generated in the recording photoconductive layer 34, and the charge that acts as a conductor for transport charges of the opposite polarity to the charges A second electrode layer in which a transport layer 35, a reading photoconductive layer 36 that generates an electric charge when irradiated with the reading light L2, and a linear electrode 37a that extends linearly that transmits the reading light L2 are arranged in parallel. 37 is laminated in this order.

  In the radiation image detector 22, the radiation L 1 is irradiated from the first electrode layer 33 side, and a latent image charge corresponding to the dose of the irradiated radiation L 1 generates a recording photoconductive layer 34 and a charge transport layer 35. A radiographic image is recorded by being accumulated in the power storage unit 38 formed at the interface with. Then, the reading light L2 irradiated from the second electrode layer 37 side passes through the linear electrode 37a and is irradiated to the reading photoconductive layer 36, and is generated in the reading photoconductive layer 36 by the irradiation of the reading light L2. The charge of one polarity is combined with the latent image charge in the power storage unit 38 and the charge of the other polarity is detected by a current detection amplifier (not shown) connected to the linear electrode 37a. Read out as a signal.

  The radiation image detector 22 and the reading light source unit 25 are installed so that the length direction of the reading light source unit 25 and the length direction of the linear electrode 37a of the radiation image detector 22 are substantially orthogonal.

  Next, the operation of the breast X-ray imaging apparatus will be described.

  First, the cassette 2 configured as described above is loaded into the cassette loading unit 14 of the photographing apparatus main body 1. And the arm part 14 in the imaging device main body 1 rotates in the arrow A direction to a predetermined position according to the imaging purpose. Next, radiation is emitted from the radiation emitting unit 12a with the subject positioned between the radiation emitting unit 12a of the arm unit 12 and the cassette loading unit 14, and the radiation passes through the subject and passes through the subject. Radiation is applied to the radiation image detector 22 in the cassette 2. Then, as described above, charges corresponding to the radiation dose are generated in the recording photoconductive layer 34 in the radiation image detector 22, and the radiation image is recorded by accumulating the charges.

  The radiographic image recorded in the radiographic image detector 22 is read as an electrical signal as described above. At this time, the position of the radiographic image is recorded without moving the position of the arm unit 14. is there. In the above case, since the moving direction (arrow Y direction) of the reading light source unit 25 in the cassette 2 changes depending on the position of the arm unit 14, it becomes difficult to move the reading light source unit 25 stably. . Therefore, in the breast X-ray imaging apparatus, the driving force of the reading light source unit 25 is changed according to the position of the arm unit 14, that is, the amount of inclination of the reading light source unit 25 in the moving direction.

  Specifically, first, the inclination amount with respect to the horizontal direction of the moving direction of the reading light source unit 25 is detected by the inclination sensor 30 provided in the cassette 2. The amount of inclination is output to the driving force changing means 27. The driving force changing means 27 controls the motor unit 28 by changing the driving force based on the input tilt amount. The driving force is changed by changing the operation amount of the following expression (1). . In the present embodiment, the amount of inclination with respect to the horizontal direction is detected on the basis of the horizontal direction, but the horizontal direction is not necessarily used as a reference, and the horizontal plane on the vertical plane including the moving direction of the reading light source is not necessarily required. A predetermined direction different from the direction may be used as a reference.

Manipulation amount = Kpx · P + Kix · I + Kdx · D (1)
Kp, Ki, Kd: Constant P: Proportional term I: Integral term D: Derivative term In addition, PID control calculates the manipulated variable by the combination of the three proportional terms, integral term and derivative term, Accordingly, fine control is realized by controlling the current flowing through the servo motor, but the method for obtaining the values of the proportional term, integral term and differential term is the same as in general PID control. Therefore, explanation is omitted. In order to obtain the values of the proportional term, integral term, and differential term, it is necessary to obtain the deviation between the speed target value and the actual speed. The speed measurement uses the encoder sensor 21a and the linear encoder 21b. Done.

  In the present embodiment, the operation amount is changed according to the tilt amount by changing the Kpx, Kix, and Kdx according to the tilt amount. Specifically, the following five types of constants (Kpx, Kix, Kdx) are set in advance, and one of the constants is determined according to the input tilt amount, and based on the determined constant. An operation amount is obtained, and a driving current corresponding to the operation amount is supplied to the motor unit 28 to control the driving force of the motor unit 28.

Movement direction is substantially horizontal (−X1 ≦ inclination amount X ≦ X1): Kp1, Ki1, Kd1
The moving direction is ascending (X1 <inclination amount X ≦ X2): Kp2, Ki2, Kd2
Movement direction is substantially vertical ascending direction (X2 <inclination amount X ≦ 90 °): Kp3, Ki3, Kd3
The moving direction is downwardly inclined (−X2 ≦ inclination amount X <−X1): Kp4, Ki4, Kd4
Movement direction is substantially vertical downward direction (−90 ° ≦ inclination amount X <−X2): Kp5, Ki5, Kd5
In addition, the magnitude relationship of the above constants is as follows.

Kp5 <Kp4 <Kp1 <Kp2 <Kp3
Ki5 <Ki4 <Ki1 <Ki2 <Ki3
Kd5 <Kd4 <Kd1 <Kd2 <Kd3
And when the motor part 28 rotates with the drive current according to the operation amount determined as mentioned above, the screw part 29a connected to the rotating shaft of the motor part 28 will rotate. Then, the gear 29b fitted to the screw portion 29a is rotated in the arrow B direction by the rotation, and the belt portion 29c is moved in the arrow Y direction by the rotation of the gear 29b. The reading light source unit 25 connected to the belt unit 29c moves in the arrow Y direction while sliding with respect to the support unit 29d by the movement of the belt unit 29c in the arrow Y direction, and the reading light source unit 25 is driven along with the movement. Then, the reading light is irradiated toward the radiation image detector 22 and scanning of the reading light is performed.

  The radiographic image of the radiographic image detector 22 is read out as an electrical signal by the scanning of the reading light, and after the scanning of the radiographic image detector 22 is completed, the reading light source unit 25 moves again to the initial position.

  According to the breast X-ray imaging apparatus, the amount of inclination of the reading light source unit 25 in the moving direction is detected, and the driving force of the reading light scanning means 26 is changed based on the detected amount of inclination. The reading light source can be stably moved without causing an increase in cost due to the use of an expensive reading light source or motor.

  In the above embodiment, the reading light source unit 25 is moved by PID control using a servo motor. However, the present invention is not limited to this. For example, a stepping motor is used as the motor unit 28 instead of a servo motor. May be. When using a stepping motor, for example, the drive current I per phase may be set as follows according to the amount of inclination.

Movement direction is substantially horizontal (−X1 ≦ inclination amount X ≦ X1): I1
The moving direction is ascending (X1 <inclination amount X ≦ X2): I2
Movement direction is substantially vertical ascending direction (X2 <inclination amount X ≦ 90 °): I3
The moving direction is downwardly inclined (−X2 ≦ inclination amount X <−X1): I4
Movement direction is substantially vertical downward direction (−90 ° ≦ inclination amount X <−X2): I5
The magnitude relationship between the drive current values is as follows.

I5 <I4 <I1 <I2 <I3
Further, instead of setting the driving current I as a steady current, the driving current may be switched between Ia and Ic (Ia> Ic) in an acceleration region and a constant speed region in the movement of the reading light source unit 25, In that case, the drive currents Ia and Ic per phase may be set as follows according to the amount of inclination.

Ia5 <Ia4 <Ia1 <Ia2 <Ia3
Ic5 <Ic4 <Ic1 <Ic2 <Ic3
Further, when the time from the start of movement of the reading light source unit 25 to the target speed is T, an acceleration table is provided so that T becomes as follows, and the acceleration table is referred to according to the acceleration obtained by referring to the acceleration table. Thus, the drive current of the stepping motor may be controlled.

Movement direction is substantially horizontal direction (−X1 ≦ inclination amount X ≦ X1): T1
The moving direction is ascending (X1 <inclination amount X ≦ X2): T2.
Movement direction is substantially vertical ascending direction (X2 <inclination amount X ≦ 90 °): T3
The moving direction is downwardly inclined (−X2 ≦ inclination amount X <−X1): T4
Movement direction is substantially vertical downward direction (−90 ° ≦ inclination amount X <−X2): T5
T5 <T4 <T1 <T2 <T3
In the case of using a stepping motor as described above, the driving force and the driving force are selected by using the W1-2 phase driving current, the 1-2 phase driving current, and the two phase driving current in order from the light load condition applied to the motor unit 28. The load may be balanced.

  In the above embodiment, the tilt amount is detected by the tilt sensor 30, but the present invention is not limited to this, and the tilt amount may be detected by another method. For example, before scanning the reading light, the reading light source unit 25 is moved in the direction of the arrow Y without emitting the reading light, and the idle scanning is performed, and the amount of inclination is determined based on the movement speed fluctuation of the reading light source unit 25 in the empty scanning. It may be detected, and the driving force of the motor unit 28 may be changed based on the amount of inclination. In addition, it is not always necessary to detect the amount of inclination. For example, when a movement speed fluctuation serving as a reference is set in advance in the driving force changing means, and the movement speed fluctuation in the idle scanning is larger than the reference movement speed fluctuation. In addition, the driving force of the reading light source unit 25 may be changed. Note that the movement speed fluctuation may be measured, for example, by measuring the fluctuation of the pulse interval of the encoder signal output from the encoder sensor 31a, that is, the frequency fluctuation of the encoder signal. Also, for example, the speed fluctuation data of one sky scan is accumulated, the arrival time to the target speed, the deviation frequency from a predetermined threshold, the periodicity, etc. are calculated, and the movement speed fluctuation is appropriate based on these. It may be determined whether it is inappropriate or not. If the movement speed fluctuation is inappropriate, for example, the drive current value (effective current) of the motor unit 28 in the idle scan is measured, and the measured drive current value is set to a preset horizontal value. If it is larger than the driving current value in the state, the constants (Kpx, Kix, Kdx) of the servo motor may be increased, or the driving current I of the stepping motor may be increased. On the other hand, when the measured drive current value is smaller than a preset drive current value in the horizontal state, the constants (Kpx, Kix, Kdx) of the servo motor are reduced, or the drive current of the stepping motor is set. What is necessary is just to reduce I. In the case of a stepping motor, the excitation method may be changed.

  In addition, a plurality of thresholds for the measured drive current value are set, and a plurality of the constants (Kpx, Kix, Kdx) or the drive current I for the threshold are set, and the measured drive current is set. The constant (Kpx, Kix, Kdx) or the driving current I may be changed stepwise according to the magnitude of the value. Further, the above-mentioned stepwise change is set to be performed in a fine range, and the above-described idle scanning and the above constants (Kpx, Kix, Kdx) or the above-mentioned until the movement speed fluctuation in the above-described idle scanning becomes a predetermined threshold or less The change of the drive current I may be repeated a plurality of times.

  Further, the shooting menu set in the shooting base body 1 may be detected as information on the tilt amount. Specifically, for example, a table in which the shooting menu and the driving force are associated with the driving force changing means is provided. The driving force changing means is prepared so that the driving force is determined by referring to the table based on the inputted shooting menu, and the driving current of the motor unit 28 is controlled based on the driving force so as to operate. do it. The imaging menu includes, for example, information indicating the imaging region, the imaging purpose, or the rotation angle of the arm, as long as the information directly or indirectly indicates the amount of inclination of the reading light source unit 25 in the moving direction. It can be anything.

  In the above embodiment, the encoder sensor 21a and the linear encoder 21b are used. However, control of a rotating system such as a rotary encoder may be used. In the above-described embodiment, the reading light scanning unit moves the reading light source unit by a belt. However, the reading light source unit may be moved by other configurations.

  In the above-described embodiment, scanning of the reading light is performed by moving only the reading light source unit. However, scanning of the reading light is performed by moving the radiation image detector while the reading light source unit is fixed. The present invention can also be applied to an apparatus that scans the reading light by moving both the reading light source unit and the radiation image detector. Specifically, for example, when the scanning means for moving the radiation image detector is one that moves the radiation image detector by driving a motor, the detected radiation image detector is similar to the above embodiment. The servo constant, drive current, excitation method, and the like may be controlled based on the amount of tilt in the moving direction. When both the radiation image detector and the reading light source unit are moved, the servo constant, drive current, excitation method, etc. of the motor to be moved are controlled based on the amount of inclination in each moving direction. You just have to do it.

  In the above embodiment, the radiation image detector 22 configured as described above is used to record a radiation image. However, the present invention is not limited to this. May be used, and a stimulable phosphor sheet using a stimulable phosphor exhibiting stimulated emission by being irradiated with reading light may be used. When the stimulable phosphor sheet is used as described above, detection means for detecting the stimulated emission light emitted from the stimulable phosphor sheet is also installed in the cassette 2.

Schematic configuration diagram of an X-ray imaging apparatus for breasts using the optical scanning apparatus of the present invention Schematic configuration diagram of a cassette used in the mammography apparatus shown in FIG. Schematic configuration diagram of the tilt sensor installed in the cassette shown in FIG. Schematic block diagram of the radiation image detector installed in the cassette shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device main body 2 Cassette 10 Imaging stand 12 Arm part 12a Radiation emission part 14 Cassette loading part 20 Housing | casing 21a Encoder sensor 21b Linear encoder 22 Radiation image detector 24 Reading light scanning device 26 Reading light scanning means 27 Driving force change means 28 Motor part 29a Screw part 29b Gear 29c Belt part 29d Support part 30 Inclination sensor 31 Electrode 32 Metal ball 33 First electrode layer 34 Recording photoconductive layer 35 Charge transport layer 36 Reading photoconductive layer 37 Second electrode layer 38 Power storage unit

Claims (6)

The radiographic image is recorded by receiving the radiation carrying the radiographic image, and the scanning beam is emitted by the scanning unit to the radiographic image recording medium which is scanned by the reading beam and reads a signal corresponding to the radiographic image. In the optical scanning method of scanning the reading light by moving at least one of the reading light source and the radiation image recording medium relatively in a direction substantially parallel to the reading light scanning surface ,
Detecting the amount of tilt in the moving direction of the reading light source or the radiation image recording medium during scanning of the reading light;
An optical scanning method characterized in that the driving force of the scanning means is changed based on the detected inclination amount. The radiographic image is recorded by receiving the radiation carrying the radiographic image, and the scanning beam is emitted by the scanning unit to the radiographic image recording medium which is scanned by the reading beam and reads a signal corresponding to the radiographic image. An optical scanning device that scans the reading light by moving at least one of the reading light source and the radiation image recording medium relatively in a direction substantially parallel to the reading light scanning surface In
A tilt amount detecting means for detecting a tilt amount in the moving direction of the reading light source or the radiation image recording medium during scanning of the reading light;
An optical scanning apparatus comprising: a driving force changing unit that changes a driving force of the scanning unit based on the amount of tilt detected by the tilt amount detecting unit. The scanning unit is installed together with the radiographic image recording medium in a cassette that is mounted on a radiographic image recording apparatus that records a radiographic image on the radiographic image recording medium and is provided separately from the radiographic image recording apparatus. And
The optical scanning device according to claim 2, wherein the inclination amount detection unit is provided in the cassette.   3. The optical scanning according to claim 2, wherein the tilt amount detecting means is provided in a loading portion of the radiographic image recording medium of a radiographic image recording apparatus that records a radiographic image on the radiographic image recording medium. apparatus.   3. The optical scanning device according to claim 2, wherein the tilt amount detection unit obtains information on the tilt amount from a radiographic image recording apparatus that records a radiographic image on the radiographic image recording medium. The scanning unit performs a blank scan to move the reading light source relatively in a direction substantially parallel to the scanning surface without emitting the reading light from the reading light source before scanning the reading light. Yes,
3. The optical scanning device according to claim 2, wherein the tilt amount detecting unit detects the tilt amount based on a moving speed fluctuation of the reading light source or the radiation image recording medium in the idle scanning.

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