Prostate CancerNCT04565457

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

A study testing Research CBCT in people with Prostate Cancer and Head and Neck Cancers, run by University of Colorado, Denver at 2 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

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. Read more about this study

Who is it for?: Ages 18 to 100 years
Conditions the study is for: Prostate Cancer, Head and Neck Cancers, Upper Abdomen Cancers
What is being tested?: Research CBCT
Type of treatment: Medical device
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 43 participants
Where: 2 sitesUnited States
Study dates: 21 Apr 2023to 28 May 2025
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 100 years
All sexes
No healthy volunteers
Adult, Older adult

Who may be able to join

Provision to sign and date the consent form.
Stated willingness to comply with all study procedures and be available for the duration of the study.
Be a male or female aged 18-100.
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.

Who cannot join

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.
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.
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:
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.

Trial locations and contacts

2 sites in 1 country.

United States2 sites

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

Other trials in United States

About this study

Read the 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.

Conditions: Prostate Cancer, Head and Neck Cancers, Upper Abdomen Cancers
Being tested: Research CBCT
Medical subject headings: Prostatic Neoplasms, Head and Neck Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Research CBCTDevice
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.

Study groups in NCT04565457
Study group	Role	What they receive
Participants Scanned	Experimental	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. Receives: Device: Research CBCT

What is being measured

The primary outcome is the main question the study is designed to answer.

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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: At time of CBCT imaging session (Day 1)

Secondary outcomes (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.
Measured: At time of CBCT imaging session.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

21 Apr 202328 May 2025

First posted25 Sep 2020
Study start21 Apr 2023
Primary completion28 May 2025
Study completion28 May 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Prostate CancerStudies of the same condition, open and under way.
More trials run by University of Colorado, DenverThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase N/A
Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Single group
Model description: Single arm study
Masking: None (open label)
Enrolment: 43 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT04565457
Sponsor's protocol ID: 20-1684.cc
Other IDs: R01CA245270
Status last verified: Apr 2026
First submitted: 18 Sep 2020
Last updated: 6 May 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes
FDA-regulated drug: No
FDA-regulated device: Yes
Individual data sharing: No

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

RecruitingPhase 1/2
Docetaxel and SX-682 in Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma, Salivary Gland Carcinoma, and Advanced Prostate Cancer
Head and Neck Cancer, Head and Neck Squamous Cell Carcinoma
Active, not recruiting
Daily Adaptive Post-Prostatectomy With Stereotactic Ablative Radiotherapy in Patients With Prostate Cancer
Malignant Prostate Neoplasm
Enrolling by invitation
Use of Tracking Devices to Locate Abnormalities During Invasive Procedures
Adenocarcinoma, Prostate Neoplasms
RecruitingObservational study
Imaging Studies to Check the Local Response of Prostate Cancer to Radiation Therapy
Prostatic Neoplasms, Prostate Cancer
RecruitingPhase 1
A Study of LY4257496 in Participants With Cancer (OMNIRAY)
Breast Neoplasms, Colorectal Neoplasms

All Prostate Cancer trials

Study at a glance

From the registry record, last updated by the sponsor on 6 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Pilot Study Evaluating the Effect of 2D Antiscatter Grids on CBCT Image Quality
ClinicalTrials.gov ID: NCT04565457
Acronym / sponsor ID: 20-1684.cc
Conditions: Prostate Cancer, Head and Neck Cancers, Upper Abdomen Cancers
Study type: Interventional
Recruitment status: Completed
Enrolment: 43 participants (actual)
Lead sponsor: University of Colorado, DenverUniversity, hospital or other
Collaborators: National Cancer Institute (NCI)
Study start: 21 Apr 2023 (actual)
Primary completion: 28 May 2025 (actual)
Study completion: 28 May 2025 (actual)
First posted: 25 Sep 2020 (actual)
Results: Posted 6 May 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Number of arms: 1
Model description: Single arm study

Arm	Type	Receives
Participants Scanned	Experimental	Device: Research CBCTAll 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.

Who may qualify

Ages: 18 to 100 years
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (4 listed)

Provision to sign and date the consent form.
Stated willingness to comply with all study procedures and be available for the duration of the study.
Be a male or female aged 18-100.
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.

Key exclusion criteria (5 listed)

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.
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.
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).

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Research CBCTEach 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.	Device	Participants Scanned

Primary outcome

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.
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.
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.
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.
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.
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.

1 secondary outcome

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.

Results and safety

Results posted to the registry on 6 May 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Photon Therapy Participants	32	32
Proton Therapy Participants	11	10

Primary outcome: Ratio of Standard CBCT to Research CBCT HU Error in Photon Therapy Participants

Time frame: At time of CBCT imaging session (Day 1). Mean (95% Confidence Interval). Unit: Ratio (unitless)

Measure	Photon Therapy Participants n = 31
Value	1.768 (1.466 to 2.132)

Photon Therapy Participants: Ratio of HU errors: 1.768 (95% CI 1.466 to 2.132), p = 0.0001, Linear mixed-effects model

Population analysed: Out of 32 participants in the photon therapy group, 31 participants with evaluable paired CBCT scans (research CBCT with 2D antiscatter grid and standard clinical CBCT) were included in this analysis. One participant was excluded due to non-evaluable imaging data caused by a CBCT technical problem during the CBC T scan.

Primary outcome: 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 (95% Confidence Interval). Unit: Change in HU error

Measure	Proton Therapy Participants n = 10
Value	-128.8 (-137.9 to -123.3)

Proton Therapy Participants: Hodges-Lehmann estimate of median shift: -128.8 (95% CI -137.9 to -123.3), p = 0.001953, Wilcoxon (Mann-Whitney)

Population analysed: Proton therapy participants with standard CBCT and research CBCT scans were included in this analysis. All 10 participants in this arm were included in the analysis.

Primary outcome: Ratio of Artifact Amplitude Between Standard CBCT and Research CBCT in Photon Therapy Participants

Time frame: At time of CBCT imaging session (Day 1). Mean (95% Confidence Interval). Unit: Ratio

Measure	Photon Therapy Participants n = 31
Value	1.489 (1.255 to 1.767)

Photon Therapy Participants: Ratio of artifact amplitude: 1.489 (95% CI 1.255 to 1.767), p = 0.0001, Linear mixed-effects model

Population analysed: 31 participants with evaluable paired CBCT scans (research CBCT with 2D antiscatter grid and standard clinical CBCT) were included in this analysis.

Primary outcome: 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 (95% Confidence Interval). Unit: Change in HU

Measure	Proton Therapy Participants n = 10
Value	-235.9 (-269.1 to -182.4)

Proton Therapy Participants: Hodges-Lehmann estimate of median shift: -235.9 (95% CI -269.1 to -182.4), p = 0.001953, Wilcoxon signed-rank test

Population analysed: All 10 proton therapy participants with paired standard CBCT and research CBCT scans were included in this analysis.

1 secondary outcome is reported in the full results.

Adverse events

Time frame: From enrollment until the completion of research CBCT scan. Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Photon Therapy Participants	0 of 32 (0%)	0 of 32 (0%)	0 of 32
Proton Therapy Participants	0 of 10 (0%)	0 of 10 (0%)	0 of 10

Limitations and caveats (from the sponsor): Research CBCT scans were performed while participants were free breathing. When organ motion was present in the scan volume, image artifacts caused by motion might have affected the values of image quality metrics in both research and standard of care CBCT scans.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 6 May 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: No

Related trials for Prostate Cancer

RecruitingPhase 1/2
Docetaxel and SX-682 in Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma, Salivary Gland Carcinoma, and Advanced Prostate Cancer
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Active, not recruiting
Daily Adaptive Post-Prostatectomy With Stereotactic Ablative Radiotherapy in Patients With Prostate Cancer
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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Cem Altunbas, PhD principal investigator

University of Colorado, Denver

2 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A study testing Research CBCT in people with Prostate Cancer and Head and Neck Cancers, run by University of Colorado, Denver at 2 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 6 May 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 6 May 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Ratio of Standard CBCT to Research CBCT HU Error in Photon Therapy Participants (time frame: At time of CBCT imaging session (Day 1)). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04565457.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 May 2026.