Abstract: When radiography is performed on a patient at a radiography apparatus, first, a past collected radiation dose for the patient and a past collected radiation dose for a region of the patient on which radiography will be performed are extracted from a database. Judgment is made as to whether the collected radiation doses are greater than or equal to respective set threshold values. If it is judged that at least one of the collected radiation doses is greater than or equal to the set threshold values, the radiography apparatus outputs an alert for a radiographer. If it is judged that the collected radiation doses are less than or equal to the set threshold values, radiography is started by the radiography apparatus.

Abstract: A reference light source produces a reference light having a predetermined light intensity. A sensitivity measuring device acquires a detection signal from an operation, in which the reference light having been produced by the reference light source is photoelectrically detected with the photomultiplier. The sensitivity measuring device measures a sensitivity of the photomultiplier in accordance with a relationship between the thus acquired detection signal and a reference signal, which has been set previously and which has a level in accordance with the predetermined light intensity of the reference light.

Abstract: A method and apparatus for estimating photmultiplier sensitivity change is provided, which is capable of properly and easily estimating the sensitivity change in a photomultiplier used in a radiation image reading unit constructed to read out a radiation image using the photomultiplier. The method and apparatus obtain exposure conditions used when the radiation image was recorded on the storage phosphor sheet by the exposure condition obtaining means, then calculate an estimated amount of radiation irradiated on the storage phosphor sheet by the sensitivity change information obtaining means based on the exposure conditions obtained by the exposure condition obtaining means, cumulatively add the estimated amount of radiation for each radiation image recorded on the storage phosphor sheet, and obtain the cumulative value of the estimated amounts as the information that indicates the sensitivity change in the photomultiplier.

Abstract: A reference light source produces a reference light having a predetermined light intensity. A sensitivity measuring device acquires a detection signal from an operation, in which the reference light having been produced by the reference light source is photoelectrically detected with the photomultiplier. The sensitivity measuring device measures a sensitivity of the photomultiplier in accordance with a relationship between the thus acquired detection signal and a reference signal, which has been set previously and which has a level in accordance with the predetermined light intensity of the reference light.

Abstract: A method and apparatus for estimating photmultiplier sensitivity change is provided, which is capable of properly and easily estimating the sensitivity change in a photomultiplier used in a radiation image reading unit constructed to read out a radiation image using the photomultiplier. The method and apparatus obtain exposure conditions used when the radiation image was recorded on the storage phosphor sheet by the exposure condition obtaining means, then calculate an estimated amount of radiation irradiated on the storage phosphor sheet by the sensitivity change information obtaining means based on the exposure conditions obtained by the exposure condition obtaining means, cumulatively add the estimated amount of radiation for each radiation image recorded on the storage phosphor sheet, and obtain the cumulative value of the estimated amounts as the information that indicates the sensitivity change in the photomultiplier.

Abstract: A stimulable phosphor sheet, on which a radiation image has been stored, is scanned with stimulating rays in a main scanning direction and moved in a sub-scanning direction, which is approximately normal to the main scanning direction. A read-out device photoelectrically detects the light, which is emitted by the stimulable phosphor sheet when the stimulable phosphor sheet is scanned with the stimulating rays in the main scanning direction, to obtain an image signal representing the radiation image. A light guiding mirror for reflecting the emitted light toward the read-out device is located to extend in the main scanning direction at a position in the vicinity of a position on the stimulable phosphor sheet, which position is scanned with the stimulating rays in the main scanning direction. The light guiding mirror is supported by a support member, which is formed from a metallic material and is electrically isolated from a ground, or which is formed from an electrical insulating material.