当前位置： SCI文献检索 > MEDICAL PHYSICS期刊下所有文献 > An interprojection sensor fusion approach to estimate blocked projection signal in synchronized moving grid-based CBCT system.

An interprojection sensor fusion approach to estimate blocked projection signal in synchronized moving grid-based CBCT system.

Abstract：

PURPOSE:A preobject grid can reduce and correct scatter in cone beam computed tomography (CBCT). However, half of the signal in each projection is blocked by the grid. A synchronized moving grid (SMOG) has been proposed to acquire two complimentary projections at each gantry position and merge them into one complete projection. That approach, however, suffers from increased scanning time and the technical difficulty of accurately merging the two projections per gantry angle. Herein, the authors present a new SMOG approach which acquires a single projection per gantry angle, with complimentary grid patterns for any two adjacent projections, and use an interprojection sensor fusion (IPSF) technique to estimate the blocked signal in each projection. The method may have the additional benefit of reduced imaging dose due to the grid blocking half of the incident radiation. METHODS:The IPSF considers multiple paired observations from two adjacent gantry angles as approximations of the blocked signal and uses a weighted least square regression of these observations to finally determine the blocked signal. The method was first tested with a simulated SMOG on a head phantom. The signal to noise ratio (SNR), which represents the difference of the recovered CBCT image to the original image without the SMOG, was used to evaluate the ability of the IPSF in recovering the missing signal. The IPSF approach was then tested using a Catphan phantom on a prototype SMOG assembly installed in a bench top CBCT system. RESULTS:In the simulated SMOG experiment, the SNRs were increased from 15.1 and 12.7 dB to 35.6 and 28.9 dB comparing with a conventional interpolation method (inpainting method) for a projection and the reconstructed 3D image, respectively, suggesting that IPSF successfully recovered most of blocked signal. In the prototype SMOG experiment, the authors have successfully reconstructed a CBCT image using the IPSF-SMOG approach. The detailed geometric features in the Catphan phantom were mostly recovered according to visual evaluation. The scatter related artifacts, such as cupping artifacts, were almost completely removed. CONCLUSIONS:The IPSF-SMOG is promising in reducing scatter artifacts and improving image quality while reducing radiation dose.

journal_name

Med Phys

journal_title

Medical physics

authors

Zhang H,Ren L,Kong V,Giles W,Zhang Y,Jin JY

doi

10.1118/1.4937934

subject

Has Abstract

pub_date

2016-01-01 00:00:00

pages

268

issue

eissn

0094-2405

issn

2473-4209

journal_volume

pub_type

杂志文章

在线工具

An interprojection sensor fusion approach to estimate blocked projection signal in synchronized moving grid-based CBCT system.