2D Antiscatter Grids on CBCT for Cancer Imaging Quality

Recruiting at 3 trial locations

Overseen By Kayla Vondran

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Colorado, Denver

Disqualifiers: Metallic implants, Pregnancy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

43 Participants Needed

Trial Summary

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It is best to discuss this with the trial coordinators or your doctor.

What data supports the effectiveness of the treatment 2D Antiscatter Grids in improving cancer imaging quality?

Research shows that two-dimensional antiscatter grids (2D grids) can significantly reduce scattered radiation, which improves image quality in cone-beam computed tomography (CBCT) by enhancing contrast and reducing noise. These grids are particularly effective in high scatter conditions, providing better image clarity compared to traditional one-dimensional grids. ^{1 2 3 4 5}

Is the use of 2D Antiscatter Grids in CBCT imaging safe for humans?

The research suggests that 2D Antiscatter Grids in CBCT imaging are generally safe, as they improve image quality by reducing x-ray scatter without significant adverse effects. However, precise alignment is necessary to maintain image quality, and the use of grids is most beneficial under specific conditions of high x-ray scatter. ^{1 2 6 7 8}

How does the 2D antiscatter grid treatment in CBCT differ from other cancer imaging treatments?

The 2D antiscatter grid treatment in CBCT is unique because it uses a two-dimensional grid to significantly reduce scattered radiation, which improves image quality by enhancing contrast and reducing artifacts. This approach is particularly effective in high scatter conditions, offering better image clarity compared to traditional one-dimensional grids used in other imaging treatments. ^{1 2 3 4 9}

What is the purpose of this trial?

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.

Research Team

Cem Altunbas, PhD

Principal Investigator

University of Colorado, Denver

Eligibility Criteria

This trial is for adults aged 18-100 who are undergoing CBCT-guided therapy for certain cancers in the upper abdomen, prostate, or head and neck. They must be able to lie still during imaging and treatment, sign a consent form, follow study procedures, and not have metallic implants in the scan area (some dental materials may be okay). Pregnant individuals cannot participate.

Inclusion Criteria

I am willing and able to follow all study rules and attend all appointments.

I will be treated with special imaging-guided therapy for cancer in my upper abdomen, prostate, or head and neck.

Provision to sign and date the consent form

Exclusion Criteria

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 will receive a pregnancy test to reconfirm eligibility)

Metallic implants in the CBCT scan volume, such as hip prostheses or spine stabilization hardware. Dental implants, filings, 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. 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, patient will be excluded from the study

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Imaging

Participants are scanned with a CBCT system equipped with 2D antiscatter grid technology and a standard clinical CBCT for baseline comparison

1-2 weeks

Observer Study

Assessment of image quality improvement in research CBCT compared to standard clinical CBCT in a blinded observer study

4 years

Follow-up

Participants are monitored for safety and effectiveness after imaging

4 weeks

Treatment Details

Interventions

• 2D Antiscatter Grids
• Research CBCT

Trial Overview The study is testing whether a new technology called a 2D antiscatter grid can improve image quality in CBCT scans used for treating specific cancers. Participants' tissue visualization will be assessed blindly by observers to see if there's an improvement.

Participant Groups

Group I: Participants Scanned Experimental Treatment 1 Intervention

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.

Who Is Running the Clinical Trial?

University of Colorado, Denver

Lead Sponsor

Trials

1,842

Recruited

3,028,000+

National Cancer Institute (NCI)

Collaborator

Trials

14,080

Recruited

41,180,000+

Findings from Research

Antiscatter x-ray grids significantly reduce scatter artifacts and improve image uniformity in cone-beam CT, particularly under high scatter conditions (SPR > 100%) and high patient doses (Dcenter > 2 cGy).

However, the overall improvement in image quality, as measured by contrast-to-noise ratio (CNR), is limited, suggesting that the use of grids may not be necessary in most situations unless specific conditions are met.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The influence of antiscatter grids on soft-tissue detectability in cone-beam computed tomography with flat-panel detectors. Siewerdsen, JH., Moseley, DJ., Bakhtiar, B., et al.[2022]

The newly developed 2D antiscatter grids for cone beam computed tomography (CBCT) significantly reduce scatter-to-primary ratios (SPR) and improve primary transmission, achieving up to 21% better performance compared to traditional 1D grids.

With a grid ratio of 16 and a pitch of 2 mm, these 2D grids maintain SPRs below 0.2 and primary transmission above 80%, enhancing image quality in high scatter conditions, although they require precise alignment during use.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of grid geometry on the transmission properties of 2D grids for flat detectors in CBCT. Altunbas, C., Alexeev, T., Miften, M., et al.[2020]

The novel two-dimensional antiscatter grid (2D-ASG) significantly improved image quality in Cone-beam computed tomography (CBCT) by enhancing contrast resolution, with contrast-to-noise ratio (CNR) improvements of up to 86% compared to no antiscatter grid and 54% compared to a conventional one-dimensional grid.

The 2D-ASG also reduced CT number underestimation in water-equivalent materials by up to 325 Hounsfield Units (HU) compared to no grid, indicating its potential for better soft tissue visualization and improved clinical applications.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Two-dimensional antiscatter grid: A novel scatter rejection device for Cone-beam computed tomography. Alexeev, T., Kavanagh, B., Miften, M., et al.[2019]

The two-dimensional antiscatter grid (2DASG) prototype significantly reduced scatter-to-primary ratios (SPR) by a factor of 3 to 6 compared to the conventional one-dimensional antiscatter grid (1DASG), indicating superior scatter suppression in cone-beam CT imaging.

The 2DASG also achieved a 19% higher average primary transmission, which, along with lower scatter, may lead to more accurate CT numbers and improved visualization of low contrast objects in radiation therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Transmission characteristics of a two dimensional antiscatter grid prototype for CBCT. Altunbas, C., Kavanagh, B., Alexeev, T., et al.[2019]

Antiscatter grids (ASGs) modestly improved contrast-to-noise ratio (CNR) in pelvic phantom images but had little to no effect on head phantom images, indicating their variable efficacy depending on the type of scan.

Beam modulating with bowtie filters (BTFs) effectively reduced scatter-to-primary ratio (SPR) and image noise, leading to a better balance between CNR and imaging dose, although it introduced a circular band artifact.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Monte Carlo evaluation of scatter mitigation strategies in cone-beam CT. Lazos, D., Williamson, JF.[2021]

Using antiscatter grids in low-dose cone-beam CT (CBCT) for image-guided surgery improves CT number accuracy significantly, reducing errors from 31% to 2% in the thorax and from 37% to 10% in the abdomen with a 12:1 grid.

However, the use of grids can lead to a substantial increase in image noise (up to 70%) and a reduction in contrast-to-noise ratio (CNR) for low-contrast soft tissues, suggesting that the benefits of grids may not outweigh the drawbacks in extended geometries like those used in mobile C-arms.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Antiscatter grids in mobile C-arm cone-beam CT: effect on image quality and dose. Schafer, S., Stayman, JW., Zbijewski, W., et al.[2021]

Routine quality assurance (QA) using cone-beam computed tomography (CBCT) is not effective at predicting clinically recognizable image quality issues, with a low sensitivity of only 17% in detecting problems during a 34-month study involving eight Varian linacs.

Among the various image quality metrics assessed, uniformity showed the best predictive performance with an area under the curve (AUC) of 0.85, but still had a high false-positive rate, indicating that current QA methods need improvement to better reflect clinical image quality.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Technical Note: Assessing the performance of monthly CBCT image quality QA. Manger, RP., Pawlicki, T., Hoisak, J., et al.[2019]

In pediatric cone beam CT (CBCT) scans, anatomical noise is the primary factor affecting image quality, contributing more than 80% to total noise, while quantum noise contributes less than 20%.

Effective soft tissue contrast and accurate registration can be achieved at doses as low as 1 mGy, indicating that increasing the dose above this level does not improve image quality or registration accuracy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low dose cone beam CT for paediatric image-guided radiotherapy: Image quality and practical recommendations. Bryce-Atkinson, A., De Jong, R., Marchant, T., et al.[2021]

The new Grid-based Scatter Sampling (GSS) method enhances the performance of 2D antiscatter grids in cone beam CT (CBCT) by not only rejecting scatter but also measuring and correcting residual scatter, leading to improved image quality.

Using GSS, the accuracy of CT number measurements significantly improved, with reductions in HU nonuniformity from 65 HU to 30 HU and a 41% reduction in noise, demonstrating its effectiveness in minimizing artifacts and enhancing quantitative imaging capabilities.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A unified scatter rejection and correction method for cone beam computed tomography. Altunbas, C., Park, Y., Yu, Z., et al.[2022]

References

1. United States pubmed.ncbi.nlm.nih.gov

The influence of antiscatter grids on soft-tissue detectability in cone-beam computed tomography with flat-panel detectors. [2022]

2. England pubmed.ncbi.nlm.nih.gov

Effect of grid geometry on the transmission properties of 2D grids for flat detectors in CBCT. [2020]

3. United States pubmed.ncbi.nlm.nih.gov

Two-dimensional antiscatter grid: A novel scatter rejection device for Cone-beam computed tomography. [2019]

4. United States pubmed.ncbi.nlm.nih.gov

Transmission characteristics of a two dimensional antiscatter grid prototype for CBCT. [2019]

5. United States pubmed.ncbi.nlm.nih.gov

Monte Carlo evaluation of scatter mitigation strategies in cone-beam CT. [2021]

6. United States pubmed.ncbi.nlm.nih.gov

Antiscatter grids in mobile C-arm cone-beam CT: effect on image quality and dose. [2021]

7. United States pubmed.ncbi.nlm.nih.gov

Technical Note: Assessing the performance of monthly CBCT image quality QA. [2019]

8. Ireland pubmed.ncbi.nlm.nih.gov

Low dose cone beam CT for paediatric image-guided radiotherapy: Image quality and practical recommendations. [2021]

9. United States pubmed.ncbi.nlm.nih.gov

A unified scatter rejection and correction method for cone beam computed tomography. [2022]