A Pilot Study Evaluating the Effect of 2D Antiscatter Grids on CBCT Image Quality

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.

Study Overview

• Status: Completed
• Conditions: Prostate Cancer; Head and Neck Cancers; Upper Abdomen Cancers
• Intervention / Treatment: Device: Research CBCT

Detailed Description

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
• Enrollment (Actual): 43
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Colorado
    • Aurora, Colorado, United States, 80045
      • University of Colorado Hospital
  • Florida
    • Jacksonville, Florida, United States, 32206
      • University of Florida Health Proton Therapy Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 100 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Provision to sign and date the consent form.
2. Stated willingness to comply with all study procedures and be available for the duration of the study.
3. Be a male or female aged 18-100.
4. Participants who will be treated or are currently being treated with CBCT-guided photon therapy for prostate or prostate-bed, abdomen head and neck, or pelvic cancers, or with image-guided proton therapy for prostate or prostate bed cancer.

Exclusion Criteria:

1. Metallic implants in the CBCT scan volume, such as hip prostheses or spine stabilization hardware. Patients with pacemakers, defibrillators, or other implanted electronic devices. Dental implants, fillings, or fiducial markers may be acceptable, and the decision for inclusion/exclusion will be on a case-by-case basis, by reviewing prior CT images of the study candidate. Patient's prior CT images will be reviewed by the PI or the site PI.
2. Patients who do not have the ability to lie still for the duration of his/her CBCT imaging and treatment should be excluded. If image artifacts in prior scans are deemed excessive, the patient will be excluded from the study.

3. Known pregnancy. (Per SOC, a pregnancy test will be performed prior to CBCT scan on Day 1. At this time, women of child-bearing potential (WOCBP) will receive a pregnancy test to re-confirm eligibility).

   • Women of child-bearing potential are described as:

     1. Age 55 or younger who have not had a negative pregnancy test within 3 days. This excludes patients who have had tubal ligation or are already post-menopausal.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Participants Scanned; 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.

Device: Research CBCT; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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.	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.	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.	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.	At time of CBCT imaging session (Day 1)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	At time of CBCT imaging session.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Concordance Correlation Coefficients	Correlation of radiomics features in CBCT images and gold standard MDCT images, as measured by correlation coefficients, such as Pearson Correlation Coefficient or Concordance Correlation Coefficient.	4 years

Collaborators and Investigators

• Sponsor: University of Colorado, Denver
• Collaborators: National Cancer Institute (NCI)
• Investigators: Principal Investigator: Cem Altunbas, PhD, University of Colorado, Denver

Study record dates

Study Major Dates

• Study Start (Actual): April 21, 2023
• Primary Completion (Actual): May 28, 2025
• Study Completion (Actual): May 28, 2025

Study Registration Dates

• First Submitted: September 18, 2020
• First Submitted That Met QC Criteria: September 24, 2020
• First Posted (Actual): September 25, 2020

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: April 15, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Prostatic Neoplasms; Head and Neck Neoplasms
• Other Study ID Numbers: 20-1684.cc; R01CA245270 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No