Deprecated: Implicit conversion from float 233.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 233.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 233.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 233.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 233.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 233.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 233.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 267.2 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 267.2 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Warning: imagejpeg(C:\Inetpub\vhosts\kidney.de\httpdocs\phplern\25281970
.jpg): Failed to open stream: No such file or directory in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 117 Med+Phys
2014 ; 41
(10
): 101918
Nephropedia Template TP
gab.com Text
Twit Text FOAVip
Twit Text #
English Wikipedia
Evaluation of tumor localization in respiration motion-corrected cone-beam CT:
prospective study in lung
#MMPMID25281970
Dzyubak O
; Kincaid R
; Hertanto A
; Hu YC
; Pham H
; Rimner A
; Yorke E
; Zhang Q
; Mageras GS
Med Phys
2014[Oct]; 41
(10
): 101918
PMID25281970
show ga
PURPOSE: Target localization accuracy of cone-beam CT (CBCT) images used in
radiation treatment of respiratory disease sites is affected by motion artifacts
(blurring and streaking). The authors have previously reported on a method of
respiratory motion correction in thoracic CBCT at end expiration (EE). The
previous retrospective study was limited to examination of reducing motion
artifacts in a small number of patient cases. They report here on a prospective
study in a larger group of lung cancer patients to evaluate respiratory
motion-corrected (RMC)-CBCT ability to improve lung tumor localization accuracy
and reduce motion artifacts in Linac-mounted CBCT images. A second study goal
examines whether the motion correction derived from a respiration-correlated CT
(RCCT) at simulation yields similar tumor localization accuracy at treatment.
METHODS: In an IRB-approved study, 19 lung cancer patients (22 tumors) received a
RCCT at simulation, and on one treatment day received a RCCT, a respiratory-gated
CBCT at end expiration, and a 1-min CBCT. A respiration monitor of abdominal
displacement was used during all scans. In addition to a CBCT reconstruction
without motion correction, the motion correction method was applied to the same
1-min scan. Projection images were sorted into ten bins based on abdominal
displacement, and each bin was reconstructed to produce ten intermediate CBCT
images. Each intermediate CBCT was deformed to the end expiration state using a
motion model derived from RCCT. The deformed intermediate CBCT images were then
added to produce a final RMC-CBCT. In order to evaluate the second study goal,
the CBCT was corrected in two ways, one using a model derived from the RCCT at
simulation [RMC-CBCT(sim)], the other from the RCCT at treatment [RMC-CBCT(tx)].
Image evaluation compared uncorrected CBCT, RMC-CBCT(sim), and RMC-CBCT(tx). The
gated CBCT at end expiration served as the criterion standard for comparison.
Using automatic rigid image registration, each CBCT was registered twice to the
gated CBCT, first aligned to spine, second to tumor in lung. Localization
discrepancy was defined as the difference between tumor and spine registration.
Agreement in tumor localization with the gated CBCT was further evaluated by
calculating a normalized cross correlation (NCC) of pixel intensities within a
volume-of-interest enclosing the tumor in lung. RESULTS: Tumor localization
discrepancy was reduced with RMC-CBCT(tx) in 17 out of 22 cases relative to no
correction. If one considers cases in which tumor motion is 5 mm or more in the
RCCT, tumor localization discrepancy is reduced with RMC-CBCT(tx) in 14 out of 17
cases (p = 0.04), and with RMC-CBCT(sim) in 13 out of 17 cases (p = 0.05).
Differences in localization discrepancy between correction models [RMC-CBCT(sim)
vs RMC-CBCT(tx)] were less than 2 mm. In 21 out of 22 cases, improvement in NCC
was higher with RMC-CBCT(tx) relative to no correction (p < 0.0001). Differences
in NCC between RMC-CBCT(sim) and RMC-CBCT(tx) were small. CONCLUSIONS:
Motion-corrected CBCT improves lung tumor localization accuracy and reduces
motion artifacts in nearly all cases. Motion correction at end expiration using
RCCT acquired at simulation yields similar results to that using a RCCT on the
treatment day (2-3 weeks after simulation).