Surreal digital illustration symbolizing combined kV/MV CBCT imaging advancements in medical diagnostics.

Revolutionizing Medical Imaging: Can Combined kV/MV CBCT Scans Reduce Scan Time and Metal Artifacts?

Soraya Malik monogram
Soraya Malik in Health & Wellness October 2026 • 4 min read.

"A deep dive into a new study exploring the potential of combined kilovoltage/megavoltage cone-beam computed tomography (kV/MV CBCT) with a high-DQE MV detector to enhance image quality and streamline medical imaging processes."


In the ever-evolving landscape of medical imaging, precision and efficiency are paramount. State-of-the-art medical linear accelerators are now commonly equipped with two imaging systems: an electronic portal imaging device (EPID) used with the treatment beam and an orthogonal kilovoltage (kV) system. These systems offer complementary information, improving localization accuracy and treatment quality.

Cone-beam computed tomography (CBCT) or kV planar imaging is typically used for patient setup, beam gating, and beam delivery verification, while the MV system is more commonly used for treatment quality assurance and exit dosimetry. Recent research explores the potential of combined kilovoltage/megavoltage (kV/MV) imaging as an avenue for innovation, focusing on reducing scan times and minimizing metal artifacts—common challenges in radiotherapy and diagnostics.

A recent study investigates the use of combined kV/MV CBCT imaging with a high Detective Quantum Efficiency (DQE) MV detector. The goal is to determine if this advanced setup can generate acceptable quality pre-treatment CBCT images at clinically acceptable dose levels. By addressing limitations related to scan time and image distortion, this research opens new possibilities for enhancing image-guided radiotherapy applications.

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CBCT’s Medical Imaging Role

Cone beam computed tomography (CBCT), also called C-arm CT, cone beam volume CT, flat panel CT, or Digital Volume Tomography, uses divergent X-rays that form a cone. It has become increasingly important for treatment planning and diagnosis in implant dentistry, ENT, and orthopedics. GE HealthCare describes advanced CBCT as providing high-resolution 3D imaging for diagnostics and treatment planning, with an emphasis on safety and efficiency. The supplied Emory source concerns Cognitively-Based Compassion Training rather than medical imaging and does not provide CBCT statistics.

Established Imaging Practice

CBCT is generally used as a three-dimensional X-ray imaging method when volumetric information is useful for diagnosis or treatment planning. Its practical value depends on the clinical question, the imaging protocol, and the quality of the resulting reconstruction. The available source material does not establish a specific standard protocol or quantify limitations such as scan time, radiation exposure, or metal artifacts. Those issues therefore require cautious interpretation rather than unsupported generalization.

Development of CBCT

The supplied material does not document a detailed historical timeline for cone beam computed tomography. It identifies CBCT as a form of X-ray computed tomography in which divergent rays form a cone. The sources also indicate that the technology is now used in areas including implant dentistry, ENT, orthopedics, diagnosis, and treatment planning. Specific milestones, dates, and foundational discoveries cannot be established from the provided sources.

How Does Combined kV/MV CBCT Imaging Work?

Surreal digital illustration symbolizing combined kV/MV CBCT imaging advancements in medical diagnostics.

The study, conducted using a Truebeam system, combined data from both 6MV and 100kVp projections. The MV data was acquired using a prototype EPID containing two scintillators: a standard copper-gadolinium oxysulfide (Cu-GOS) screen and a prototype focused cadmium tungstate (CWO) pixelated “strip.” The kV data was acquired using a standard onboard imager. Image quality was then evaluated using phantoms—an 18-cm diameter electron density phantom and a 20-cm diameter Catphan phantom—analyzing contrast and resolution.

To simulate metal artifact reduction (MAR), researchers replaced two CIRS phantom inserts with steel rods. They based reconstruction methods on combining MV and kV data into a single sinogram, using mostly kV raw data and replacing rays corrupted by metal with MV data. For scan time reduction (STR), projections from partially overlapping kV and MV acquisitions were combined, and the resultant images were compared against MV-only and kV-only reconstructions.

  • Scan Time Reduction (STR): Projections from partially overlapping 105° kV and MV acquisitions were combined to create a complete data set, potentially achievable in just 18 seconds.
  • Metal Artifact Reduction (MAR): The reconstruction process utilized primarily kV raw data, with MV data selectively replacing rays corrupted by metal, thus reducing distortions.
  • Dose Levels: The total absorbed dose for MAR was approximately 0.7 cGy, while the STR combined acquisition resulted in about 2.5 cGy.
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Current Evidence Landscape

The supplied material does not include a research paper or review evaluating combined kV/MV CBCT scans. It does describe CBCT as a high-resolution three-dimensional imaging approach used for diagnostics and treatment planning. Whether combining kV and MV acquisitions reduces scan time or metal artifacts remains unresolved in this source set. Conclusions about clinical effectiveness would require direct comparative evidence.

Evidence Gaps and Risks

The available sources do not report specific failed studies, adverse outcomes, or measured shortcomings of combined kV/MV CBCT. They also do not provide comparative data showing how metal implants affect image quality or how scan duration changes under different protocols. Claims about failure modes should therefore remain provisional. More direct testing would be needed before presenting combined scans as a proven solution.

CBCT Versus Conventional Dental X-rays

A CBCT scan produces a detailed three-dimensional image of the teeth, jawbone, nerves, and surrounding structures. By contrast, a standard dental X-ray provides a flat, two-dimensional picture. The cited description states that CBCT captures a full three-dimensional volume in a single rotation, allowing assessment of bone depth and nerve positions. This comparison addresses dental imaging and does not by itself establish the performance of combined kV/MV CBCT.

The results indicated that the high-DQE MV detector significantly improved image quality for both STR and MAR applications. In combined kV/CWO STR reconstruction, all contrast inserts were visible, whereas only two were detectable in the kV/Cu-GOS image due to high noise levels. Similarly, in kV-MV MAR reconstructions, streaking artifacts were substantially reduced, making all inserts clearly visible in the kV/CWO image.

The Future of Medical Imaging

This study confirms that a high-DQE MV detector can be effectively applied to generate high-quality combined kV/MV images for SRT and MAR, using clinically acceptable doses. By significantly reducing scan times and minimizing artifacts caused by metal implants, this technology promises to improve diagnostic accuracy and streamline radiotherapy planning. As medical imaging technology continues to advance, innovations like combined kV/MV CBCT imaging will play a crucial role in shaping the future of healthcare.

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A Promising but Unsettled Approach

CBCT is established as a three-dimensional imaging technique with applications in diagnosis and treatment planning. However, the supplied material does not directly evaluate whether combining kV and MV scans improves scan time or metal-artifact performance. A balanced synthesis therefore treats the combined approach as an investigative possibility rather than a demonstrated clinical advance. Stronger conclusions require studies that measure both image quality and workflow outcomes.

Questions for Future Research

Future work could assess combined kV/MV CBCT against conventional CBCT using consistent measures of scan duration, image resolution, and metal artifacts. The provided sources establish the relevance of high-resolution 3D imaging to diagnosis and treatment planning but do not forecast specific technical developments. Research should also clarify which clinical applications benefit most from combined acquisitions. Until such evidence is available, projected advantages remain uncertain.

Implementation Challenges

CBCT is used across several clinical areas, including implant dentistry, ENT, orthopedics, diagnosis, and treatment planning. Applying a new combined kV/MV protocol across these settings could require evidence that it is safe, efficient, and appropriate for each use. The supplied sources do not describe equipment costs, training requirements, access disparities, or workflow barriers. These systemic considerations therefore remain important but unresolved.

Clinical Benefits for Patients

Three-dimensional CBCT imaging can help clinicians visualize structures such as teeth, jawbone, nerves, and surrounding anatomy. GE HealthCare presents high-resolution CBCT as supporting accurate diagnostics and treatment planning, with enhanced safety and efficiency. These potential benefits matter to patients because clearer anatomical information may support clinical decision-making. The provided material does not show whether combined kV/MV scans improve patient outcomes or reduce time in the imaging room.

What the combined images add, and what the comparisons mean

The combined reconstructions show that the MV detector’s design matters: the focused CWO detector preserved visible contrast inserts in conditions where the Cu-GOS version did not. This supports an image-quality advantage for that detector in the tested reconstructions, rather than establishing that every combined kV/MV setup performs the same way.[1]

The dose comparison suggests that dose to the target and dose to healthy tissue can move differently when the distribution is asymmetric. Its figures are not directly interchangeable across the reported units and presets, so they do not alone establish a general dose advantage for combined imaging.[2]

Metal visibility also depends on imaging mode: the cited comparison found artifacts absent in MV-CBCT images, severe in kVCT images, and diminished but still present after that scanner’s metal-artifact reduction. That result provides a useful contrast, but it is not a direct test of the combined reconstruction described in the article.[3]

How the detector and acquisition fit the imaging landscape

The cited description places perpendicular kV-CBCT as the commonly used pretreatment imaging method, while MV-CBCT had more limited use, associated with lower soft-tissue contrast and quantum efficiency. The combined-imaging work addresses that detector limitation with a prototype EPID using a standard Cu-GOS screen and a focused CWO strip; their reported zero-frequency DQE values were 1.4% and 22%, respectively.[1] [2]

The reconstruction joins MV and kV measurements into one sinogram, rather than treating the acquisitions as unrelated images. The reported feasibility concern was the low DQE of commercially available EPIDs, so the prototype detector is central to interpreting the image-quality results.[1]

The reported work describes high-quality combined images for scan-time reduction and metal-artifact reduction using clinically acceptable doses. That is evidence of technical feasibility under the tested conditions, not proof of clinical benefit or performance across other equipment and settings.[1]

What comparisons would clarify the approach

  • How would the dose distribution and image quality compare under the same acquisition conditions, especially when target-region and healthy-tissue dose do not shift in parallel?[1] [2]

Sources

  1. Investigation of combined kV/MV CBCT imaging with a high-DQE MV detector. (pubmed.ncbi.nlm.nih.gov)
  2. Phantom-based evaluation of dose exposure of ultrafast combined kV-MV-CBCT towards clinical implementation for IGRT of lung cancer (pmc.ncbi.nlm.nih.gov)
  3. Characterization of the Megavoltage Cone-Beam Computed Tomography (MV-CBCT) System on HalcyonTM for IGRT: Image Quality Benchmark, Clinical Performance, and Organ Doses (pmc.ncbi.nlm.nih.gov)

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

Everything You Need To Know

1

What are the primary benefits of using combined kilovoltage/megavoltage (kV/MV) cone-beam computed tomography (CBCT) in medical imaging?

The key advantages of combined kV/MV CBCT imaging include significantly reduced scan times and the minimization of metal artifacts. By integrating data from both kV and MV projections and using a high Detective Quantum Efficiency (DQE) MV detector, this approach enhances image quality, leading to quicker diagnoses and improved accuracy in radiotherapy planning. The method reduces distortions caused by metal implants which helps to produce clearer images compared to using kV or MV alone.

2

How does the combined kV/MV CBCT imaging technique specifically address the issue of metal artifacts in medical images?

To reduce metal artifacts, the reconstruction process in combined kV/MV CBCT imaging primarily uses kV raw data, but strategically replaces rays corrupted by metal with MV data. This method is based on the principle that MV data is less susceptible to metal artifacts due to the higher energy of the megavoltage beam. By combining these data sets, distortions and streaking artifacts caused by metal implants are significantly reduced, resulting in clearer visualization of the regions surrounding the metal. The prototype EPID is an integral part of this.

3

What role does the high Detective Quantum Efficiency (DQE) MV detector play in enhancing the performance of combined kV/MV CBCT imaging?

The high DQE MV detector is critical because it improves image quality for both scan time reduction (STR) and metal artifact reduction (MAR) applications. In STR, it allows for visualization of contrast inserts that would otherwise be undetectable due to high noise levels when using standard detectors like the copper-gadolinium oxysulfide (Cu-GOS) screen. Similarly, in MAR, the high DQE MV detector enables clear visualization of inserts by substantially reducing streaking artifacts, which are significant factors in obtaining high-quality images. The prototype focused cadmium tungstate (CWO) pixelated strip enhances the images obtained.

4

Can you explain how combined kV/MV CBCT imaging achieves a reduction in scan time, and what are the typical dose levels associated with this technique?

Scan time reduction (STR) in combined kV/MV CBCT is achieved by combining projections from partially overlapping kV and MV acquisitions to create a complete dataset. For instance, projections from 105° kV and MV acquisitions can be combined, potentially completing a scan in approximately 18 seconds. The total absorbed dose for scan time reduction using this combined acquisition is about 2.5 cGy. This efficient data acquisition process minimizes the overall time required for imaging without compromising image quality, using a Truebeam system, contributing to a streamlined workflow in medical settings.

5

What are the implications of using combined kV/MV CBCT imaging with a high-DQE MV detector for the future of medical imaging and radiotherapy planning?

The use of combined kV/MV CBCT imaging with a high-DQE MV detector signals a significant advancement in medical imaging and radiotherapy planning. By effectively reducing scan times and minimizing metal artifacts, this technology enhances diagnostic accuracy, leading to more precise and efficient radiotherapy planning. This also enables the generation of high-quality combined kV/MV images at clinically acceptable dose levels. As medical imaging technology continues to evolve, innovations like combined kV/MV CBCT imaging will play a crucial role in improving patient outcomes and shaping the future of healthcare, contributing to more effective and personalized treatment strategies.

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