|Title:||Phase-specific cone beam computed tomography reduces reconstructed volume loss of moving phantom||Authors:||Chao, H. -L.
Chen, W. -L.
Hu, C. -C.
Wu, J. -K.
Wu, C. -J.
Cheng, J. C. -H.
|Keywords:||Fan-beam computed tomography;Cone-beam computed tomography;Volume;Motion;Phase||Issue Date:||2012||Start page/Pages:||77-83||Source:||Strahlentherapie und Onkologie||Abstract:||
The accurate volumetric calculation of moving targets/organs is required to use cone-beam computed tomography (CBCT) for replanning purposes. This study was aimed to correct the reconstructed volume losses of moving phantoms by phase-specific CBCT. ;Planning fan-beam CT (FBCT) of five hepatobiliary/gastrointestinal/pancreatic cancer patients were acquired under active breathing control and compared with free-breathing CBCT for kidney volumes. Three different-sized ball phantoms were scanned by FBCT and CBCT. Images were imported to a planning system to compare the reconstructed volumes. The phantoms were moved longitudinally on an oscillator with different amplitudes/frequencies. The phase-specific projections of CBCT for moving phantoms were selected for volume reconstruction. ;The differences in reconstructed volumes of static small, medium, large phantoms between FBCT and CBCT were -aEuro parts per thousand 6.7%, -aEuro parts per thousand 2.3%, and -aEuro parts per thousand 2.0%, respectively. With amplitudes of 7.5-20 mm and frequencies of 8-16 oscillations/min, volume losses on CBCT were comparable with FBCT in large moving phantoms (range 9.1-27.2%). Amplitudes were more subject to volume losses than frequencies. On phase-specific CBCT, volume losses were reduced to 2.3-6.5% by reconstruction using 2-3 projections at end/midoscillation phase. ;Amplitude had more impact than frequency on volume losses of moving phantoms on CBCT. Phase-specific CBCT reduced volume losses.
|Appears in Collections:||臨床醫學研究所|
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