Radiation imaging device

摘要

Disclosed is an X-ray imaging apparatus in which a correction function used to correct scattered X-rays and a correction function used to correct beam hardening can be simply and precisely determined so that the correcting operations are performed in an appropriate sequence using the correction functions thus determined to enhance the precision in the correction and improve the image quality. The scattered X-rays and the beam hardening are corrected sequentially in this order, using the scattered X-ray correction function and the beam hardening correction function, both calculated using measured data for calculating the correction functions. The scattered X-ray correction function approximates as to each transmission distance, the data measured with changes in the transmission distance and with changes in the scattered X-ray amount, and associates the correction value thus obtained with transmittance data. Upon calculation of the beam hardening correction function, data measured with changes in the transmission distance is converted into projection data and is linearly approximated to obtain an ideal amount of beam hardening.

主权项

1. A radiation imaging apparatus, comprising:
a radiation source for irradiating a subject with radiation; a detector having multiple pixels for detecting the radiation; a storage means for storing a scattered radiation correction function for correcting influence of scattered radiation on a detection result obtained from the detector, and a beam hardening correction function for correcting influence of beam hardening on the corrected detection result; and a correction means for correcting the detection result by the scattered radiation correction function, and for correcting the corrected detection result by the beam hardening correction function, wherein the scattered radiation correction function is calculated by using data measured with changes in a transmission distance and with changes in a scattered radiation amount, and returns a correction value of the scattered radiation amount in response to the detection result, wherein the scattered radiation correction function is obtained by approximating a relation between a first transmittance data item corresponding to a first scattered radiation amount obtained from a first function that approximates a relation between the transmittance data and the scattered radiation amount with respect to each transmission distance, and a difference value obtained by subtracting the transmittance data when the scattered radiation amount obtained from the first function is nearly zero, from the first transmittance data item, and wherein the correction means converts the detection result detected by the detector using the first scattered radiation amount, into the transmittance data, and corrects the influence of the scattered radiation by subtracting the correction value calculated from the transmittance data from the transmittance data.