Cone-beam CT with megavoltage beams and an amorphous silicon electronic portal imaging device: Potential for verification of radiotherapy of lung cancer

被引:77
作者
Ford, EC
Chang, J
Mueller, K
Sidhu, K
Todor, D
Mageras, G
Yorke, E
Ling, CC
Amols, H
机构
[1] Mem Sloan Kettering Canc Ctr, Dept Med Phys, New York, NY 10021 USA
[2] SUNY Stony Brook, Dept Comp Sci, Stony Brook, NY 11794 USA
关键词
D O I
10.1118/1.1517614
中图分类号
R8 [特种医学]; R445 [影像诊断学];
学科分类号
1002 ; 100207 ; 1009 ;
摘要
We investigate the potential of megavoltage (MV) cone-beam CT with an amorphous silicon electronic portal imaging device (EPID) as a tool for patient position verification and tumor/organ motion studies in radiation treatment of lung tumors. We acquire 25 to 200 projection images using a 22 x 29 cm EPID. The acquisition is automatic and requires 7 minutes for 100 projections; it can be synchronized with respiratory gating. From these images, volumetric reconstruction is accomplished with a filtered backprojection in the cone-beam geometry. Several important pre-reconstruction image corrections, such as detector sag, must be applied. Tests with a contrast phantom indicate that differences in electron density of 2% can be detected with 100 projections, 200 cGy total dose. The contrast-to-noise ratio improves as the number of projections is increased. With 50 projections (100 cGy), high contrast objects are visible, and as few as 25 projections yield images with discernible features. We identify a technique of acquiring projection images with conformal beam apertures, shaped by a multileaf collimator, to reduce the dose to surrounding normal tissue. Tests of this technique on an anthropomorphic phantom demonstrate that a gross tumor volume in the lung can be accurately localized in three dimensions with scans using 88 monitor units. As such, conformal megavoltage cone-beam CT can provide three-dimensional imaging of lung tumors and may be used, for example, in verifying respiratory gated treatments. (C) 2002 American Association of Physicists in Medicine.
引用
收藏
页码:2913 / 2924
页数:12
相关论文
共 41 条
[1]  
BALTER J, 1996, TELETHERAPY PRESENT, P471
[2]  
BARRETT H H, 1976, Computers in Biology and Medicine, V6, P307, DOI 10.1016/0010-4825(76)90068-8
[3]   High-precision prostate cancer irradiation by clinical application of an offline patient setup verification procedure, using portal imaging [J].
Bel, A ;
Vos, PH ;
Rodrigus, PTR ;
Creutzberg, CL ;
Visser, AG ;
Stroom, JC ;
Lebesque, JV .
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 1996, 35 (02) :321-332
[4]   RADIOTHERAPEUTIC COMPUTED-TOMOGRAPHY WITH SCANNED PHOTON BEAMS [J].
BRAHME, A ;
LIND, B ;
NAFSTADIUS, P .
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 1987, 13 (01) :95-101
[5]   Characterization of an amorphous silicon fluoroscopic imager [J].
Colbeth, RE ;
Allen, MJ ;
Day, DJ ;
Gilblom, DL ;
KlausmeierBrown, ME ;
Pavkovich, J ;
Seppi, EJ ;
Shapiro, EG .
PHYSICS OF MEDICAL IMAGING - MEDICAL IMAGING 1997, 1997, 3032 :42-51
[6]   Effect of scattered radiation on image noise in cone beam CT [J].
Endo, M ;
Tsunoo, T ;
Nakamori, N ;
Yoshida, K .
MEDICAL PHYSICS, 2001, 28 (04) :469-474
[7]   PRACTICAL CONE-BEAM ALGORITHM [J].
FELDKAMP, LA ;
DAVIS, LC ;
KRESS, JW .
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, 1984, 1 (06) :612-619
[8]   Evaluation of respiratory movement during gated radiotherapy using film and electronic portal imaging [J].
Ford, EC ;
Mageras, GS ;
Yorke, E ;
Rosenzweig, KE ;
Wagman, R ;
Ling, CC .
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 2002, 52 (02) :522-531
[9]   COMPTON SCATTER EFFECTS IN CT RECONSTRUCTIONS [J].
GLOVER, GH .
MEDICAL PHYSICS, 1982, 9 (06) :860-867
[10]   Adaptive portal CT reconstruction: A simulation study [J].
Guan, HQ ;
Yin, FF ;
Zhu, YP ;
Kim, JH .
MEDICAL PHYSICS, 2000, 27 (10) :2209-2214