This is Pilot study that investigates the CBCT(Cone beam computed tomography) image quality improvement provided by the 2D antiscatter grid technology. The primary objective is to assess the improvement in tissue visualization in an observer study, which will be conducted in a blinded fashion.
This is a single arm study, where all participants will be scanned with a CBCT system equipped with 2D antiscatter grid technology, referred to as research CBCT. Each participant will also be scanned with a standard clinical CBCT as part of their standard clinical care, which will serve as the baseline, or control. Thus, the image quality improvement in research CBCT will assessed with respect to standard clinical CBCT.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
43
Each study participant will receive one additional CBCT scan, with 2D antiscatter grid in place. This is the only intervention in the study, referred as research CBCT scan, and it will be performed on one of the days during the participant's radiation treatment course. This additional research CBCT scan will be used strictly for the objectives of this study. It will not be used as part of the standard clinical care, such as imaging guidance of participant's radiation treatment or diagnostic purposes. To deliver participant's radiation treatment under CBCT guidance, a standard clinical CBCT scan will be acquired, as in standard clinical care protocols.
University of Colorado Hospital
Aurora, Colorado, United States
University of Florida Health Proton Therapy Institute
Jacksonville, Florida, United States
Ratio of Standard CBCT to Research CBCT HU Error in Photon Therapy Participants
Ratio of HU error for standard clinical CBCT (iteratively reconstructed) relative to research CBCT with 2D antiscatter grid in photon therapy participants. HU error was assessed in corresponding regions of interest, and the ratio was estimated using a linear mixed-effects model. A ratio greater than 1 would indicate higher HU error in standard CBCT than in research CBCT. A ratio less than 1 would indicate higher HU error in research CBCT than in standard CBCT.
Time frame: At time of CBCT imaging session (Day 1)
Median Shift in Hounsfield Unit (HU) Error Between Standard CBCT and Research CBCT in Proton Therapy Participants
Median paired shift in Hounsfield Unit (HU) error between research CBCT and standard clinical CBCT scans in participants receiving proton radiation therapy. HU error was evaluated in corresponding regions of interest in paired scans. The Hodges-Lehmann estimate of the median shift and its 95% confidence interval were calculated, and paired differences were evaluated using a Wilcoxon signed-rank test.
Time frame: At time of CBCT imaging session (Day 1)
Ratio of Artifact Amplitude Between Standard CBCT and Research CBCT in Photon Therapy Participants
Ratio of artifact amplitude between standard clinical CBCT (iteratively reconstructed) and research CBCT scans in participants receiving photon radiation therapy. Artifact amplitude was measured in corresponding regions of interest. The ratio of artifact amplitude between standard CBCT and research CBCT was estimated using a linear mixed-effects model. Ratio greater than 1 would indicate that standard CBCT has greater artifact amplitude than research CBCT.
Time frame: At time of CBCT imaging session (Day 1)
Median Shift in Artifact Amplitude (Measured in Hounsfield Units) Between Standard CBCT and Research CBCT in Proton Therapy Participants
Median paired shift in Artifact Amplitude between research CBCT and standard clinical CBCT scans in participants receiving proton radiation therapy. Artifact Amplitude error was evaluated in corresponding regions of interest in paired scans. The Hodges-Lehmann estimate of the median shift and its 95% confidence interval were calculated, and paired differences were evaluated using a Wilcoxon signed-rank test.
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Time frame: At time of CBCT imaging session (Day 1)
Ratio of Contrast-To-Noise Ratio (CNR) Between Standard CBCT and Research CBCT in Photon Therapy Participants
Ratio of CNR between standard clinical CBCT and research CBCT scans in participants receiving photon radiation therapy. CNR was quantified in corresponding regions of interest in paired standard and research CBCT scans of each participant. The ratio of CNR between standard CBCT and research CBCT was estimated using a linear mixed-effects model.
Time frame: At time of CBCT imaging session (Day 1)
Median Shift in Contrast to Noise Ratio (CNR) Between Standard CBCT and Research CBCT in Proton Therapy Participants
Median paired shift in CNR between research CBCT and standard clinical CBCT scans in participants receiving proton radiation therapy. CNR was evaluated in corresponding regions of interest in paired scans. The Hodges-Lehmann estimate of the median shift and its 95% confidence interval were calculated, and paired differences were evaluated using a Wilcoxon signed-rank test.
Time frame: At time of CBCT imaging session (Day 1)
Accuracy of Automated Tissue Delineation in CBCT Images for Photon Therapy Participants. Difference in Dice Similarity Coefficient Between Research CBCT and Standard CBCT
Similarity between anatomical structures delineated by auto-segmentation software and expert observer contours in research CBCT and standard clinical CBCT images was evaluated using the Dice similarity coefficient. The pairwise difference in Dice coefficients between standard clinical CBCT and research CBCT images was calculated. Higher Dice coefficients indicate greater similarity between auto-segmented and expert-drawn contours and higher accuracy in automated tissue delineation.
Time frame: At time of CBCT imaging session.