TY - JOUR
T1 - Estimation of scattered photons in gamma ray transmission CT using Monte Carlo simulations
AU - Ogawa, K.
AU - Kawamura, Y.
AU - Kubo, A.
AU - Ichihara, T.
N1 - Funding Information:
Quantitative SPECT (single photon emission computed tomography) is indispensable in the imaging of cerebral blood flow and myocardial perfusion. For the reconstruction of quantitative SPECT images, it is important to perform proper attenuation correction on the scatter-corrected data that consist of primary photons. For the scatter correction we have reported the triple-energy-window (TEW) method which corrects scattered photons in the projection data pixel by pixel [1]-[3]. Recently, many researchers have proposed several scatter correction methods and the accuracy of these correction methods looks almost the same. On the other hand, for attenuation correction many methods are proposed and they are divided into two groups: one is methods assuming a uniform attenuation, and the other is methods which employ a measured attenuation map. The former methods correct the reconstructed 'This work was supported in part by the Department of Education of Japan under Grant 07457202 in Aid for Scientific Research.
PY - 1997
Y1 - 1997
N2 - Quantitative image reconstruction in single photon emission CT requires an accurate attenuation map of a cross section of an object. Several data acquisition geometries have been proposed to obtain the true attenuation map by means of gamma-ray transmission CT (TCT). In the transmission data scattered photons are sometimes measured and they reduce the accuracy of reconstructed TCT images. To investigate the effects of scattered photons in gamma-ray transmission CT, we performed Monte Carlo simulations for several types of data acquisition systems. Examined geometries were (a) an uncollimated flood source and a parallel hole collimator, (b) a collimated flood source and a parallel hole collimator, (c) an uncollimated line source and a symmetric fan beam collimator, and (d) a collimated line source and a symmetric fan beam collimator. The results showed that a fan beam collimator and a line source rejected most of the scattered photons generated inside an object, and that if we collimated emitted photons at the source side, almost all the scattered photons could be rejected at the collimator on the detector side.
AB - Quantitative image reconstruction in single photon emission CT requires an accurate attenuation map of a cross section of an object. Several data acquisition geometries have been proposed to obtain the true attenuation map by means of gamma-ray transmission CT (TCT). In the transmission data scattered photons are sometimes measured and they reduce the accuracy of reconstructed TCT images. To investigate the effects of scattered photons in gamma-ray transmission CT, we performed Monte Carlo simulations for several types of data acquisition systems. Examined geometries were (a) an uncollimated flood source and a parallel hole collimator, (b) a collimated flood source and a parallel hole collimator, (c) an uncollimated line source and a symmetric fan beam collimator, and (d) a collimated line source and a symmetric fan beam collimator. The results showed that a fan beam collimator and a line source rejected most of the scattered photons generated inside an object, and that if we collimated emitted photons at the source side, almost all the scattered photons could be rejected at the collimator on the detector side.
UR - https://www.scopus.com/pages/publications/0344424808
UR - https://www.scopus.com/pages/publications/0344424808#tab=citedBy
U2 - 10.1109/23.596992
DO - 10.1109/23.596992
M3 - Article
AN - SCOPUS:0344424808
SN - 0018-9499
VL - 44
SP - 1225
EP - 1230
JO - IEEE Transactions on Nuclear Science
JF - IEEE Transactions on Nuclear Science
IS - 3 PART 2
ER -