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

April 15, 2026 updated by: University of Colorado, Denver
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

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
43

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

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

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Ratio of Standard CBCT to Research CBCT HU Error in Photon Therapy Participants
Time Frame: At time of CBCT imaging session (Day 1)
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
Time Frame: At time of CBCT imaging session (Day 1)
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
Time Frame: At time of CBCT imaging session (Day 1)
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
Time Frame: At time of CBCT imaging session (Day 1)
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
Time Frame: At time of CBCT imaging session (Day 1)
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
Time Frame: At time of CBCT imaging session (Day 1)
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
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
Time Frame: At time of CBCT imaging session.
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

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Concordance Correlation Coefficients
Time Frame: 4 years
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

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Colorado, Denver

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Cancer Institute (NCI)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Cem Altunbas, PhD, University of Colorado, Denver

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 21, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 28, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 28, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 18, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 24, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 25, 2020

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 6, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 15, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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