(122 days)
The CORVUS system is a radiation treatment planning package designed to allow medical physicists, dosimetrists, and radiation oncologists to create conformal treatment plans using photon (x-ray, gamma ray) external beam radiation therapy. The treatment plans generated by CORVUS are based upon treatment machine-specific data and are intended to provide a guide to delivering external beam radiation therapy which conforms to the target volume defined by the radiation oncologist.
The CORVUS system is valid for use only with external beam photon therapy; calculations for electrons and intracavity sources (Brachytherapy) are NOT supported.
CORVUS is a semi-automatic planning system: For forward planning, the system allows the user to design a treatment plan. For IMRT, rather than simply verifying a user-designed plan, the system itself suggests a plan. A clinician then reviews and approves the plan.
CORVUS is designed to generate plans for treatment delivery systems that can create multiple radiation patterns composed of pencil beams on which the intensity can be individually controlled. The treatment beams are weighted so that when they are projected into the treatment space they superimpose to give the desired dose distribution.
Each radiation field is generated using one of several optimization methods provided with the system, including simulated annealing and gradient descent.
The treatment beams are set not only to deliver the prescribed dose to the identified target volume, but also to keep the dose to other sensitive volumes below user-defined limits. Planning is done volumetrically: the beam weights for treating the entire target volume are generated simultaneously. The dose matrix is volumetric. The dose to each point is calculated to be that received from all beams and from all gantry angles. Dosage is calculated using a finite size pencil beam (FSPB) algorithm based on the beam characterization of clinically measured data. The degree to which a treatment plan is optimized is determined in part by constraints placed on the planning algorithm. The user has direct control over these constraints, which include dose goals to the target structures, dose limits to the sensitive structures, and the specification of arcs or fixed gantry positions in the treatment plan.
CORVUS treatment plans need not have the isocenter located within the target volume. An unlimited number of targets falling within the treatment volume can be planned for at the same time. Dose may be prescribed for up to 32 structures, 29 of them user-selectable, any number of which may be separate targets or radiation-sensitive structures. Each structure can have a separate dose prescription.
The CORVUS system is a radiation treatment planning package. The provided text, which appears to be an FDA 510(k) summary, focuses on demonstrating substantial equivalence to a predicate device (CORVUS 2011, K151469) rather than detailing specific acceptance criteria and a study proving device performance against those criteria in a typical clinical performance study format.
However, based on the Summary of Testing section (L), we can infer how performance was assessed for the purpose of demonstrating substantial equivalence.
Here's an attempt to structure the information according to your request, extracting what's available and noting what is not explicitly stated in the provided text.
Acceptance Criteria and Device Performance Study for CORVUS (K201350)
The provided document, an FDA 510(k) summary, describes the CORVUS system as a radiation treatment planning package. The core purpose of this submission is to demonstrate substantial equivalence to a predicate device (CORVUS 2011, K151469). Therefore, the "acceptance criteria" and "study" described herein are primarily focused on design verification and validation tests to ensure the new device functions as intended, mitigates risks, and is equivalent to its predicate.
1. Table of Acceptance Criteria (Inferred) and Reported Device Performance
Since explicit, quantifiable acceptance criteria with corresponding performance metrics are not presented in a direct table in this document, they are inferred from the verification and validation (V&V) activities described. The reported performance is generally stated as meeting requirements and demonstrating substantial equivalence.
| Acceptance Criteria Category (Inferred) | Specific Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|---|
| Functional & System Performance | Device functionality works as per its intended use. | Met design requirements and specifications through system tests and run-through integration tests. |
| Risk Mitigation & Safety | All risks are mitigated; raises no new issues of safety or effectiveness compared to the predicate. | Documented through "Summary of Testing" and "Comparison to Predicate Device" sections; stated that "no new issues of safety or effectiveness" are raised. Anomaly verification was performed. |
| Clinical Workflow & Usability | Usability is appropriate for medical physicists, dosimetrists, and radiation oncologists. | Demonstrated through clinical workflow and treatment planning software usability validation activities. Conforms to IEC 62366-1. |
| Clinical Plan Quality & Optimization | Produces conformal treatment plans that help achieve target goals while sparing sensitive structures, similar to predicate. | Evaluated through clinical plan quality/optimization comparison. Results were deemed satisfactory to demonstrate substantial equivalence. |
| Dosimetric Accuracy | Dose calculations are accurate, particularly for Cobalt-60 based treatment planning (new feature) and X-ray. | Verified through comparison with medical physics measurements, including film and ion chamber measurements. The pencil-beam algorithm and homogeneous/EPL options (and LDI for X-ray) are consistent with the predicate. |
| Substantial Equivalence | Device is substantially equivalent to predicate device CORVUS 2011 (K151469). | "The verification and validation results demonstrate that the CORVUS 14 system... is substantially equivalent to its predicate device." The key difference, Cobalt-60 support, was tested and deemed not to raise new safety/effectiveness concerns. |
| MDR & Regulatory Compliance | Conforms to applicable standards (IEC 62304, IEC 62366-1, IEC 61217, IEC 62083). Software level of concern: "Major". | Demonstrated compliance with all listed IEC standards. |
2. Sample Sizes and Data Provenance for Test Set
The document does not explicitly state the sample size (e.g., number of patient cases, treatment plans) used for the "test set" in the context of clinical plan quality, optimization, or dosimetric accuracy.
- Sample Size: Not explicitly stated. The document refers to "comparison with medical physics measurements including film and ion chamber measurements" and "clinical plan quality / optimization comparison," implying multiple cases or scenarios were tested.
- Data Provenance: Not explicitly stated. It is typical for such V&V studies to use a combination of simulated data, phantom data, and potentially de-identified clinical data. Given the "medical physics measurements" and "clinical plan quality" evaluations, it's likely that phantom data and potentially retrospective clinical cases were used, but the document does not specify country of origin or whether data was retrospective or prospective.
3. Number of Experts and Qualifications for Ground Truth
The document mentions "medical physicists, dosimetrists, and radiation oncologists" as users of the system and participants in activities like "clinical workflow" and "clinical plan quality / optimization comparison." However, it does not specify:
- Number of Experts: Not explicitly stated.
- Qualifications of Experts: It implies that these are qualified professionals (e.g., medical physicists, radiation oncologists) who would typically have extensive experience in radiation therapy planning and delivery. Specific years of experience are not mentioned. Their role would be to evaluate the usability and clinical appropriateness of the plans generated by CORVUS, likely against established clinical best practices or phantom measurements used as ground truth.
4. Adjudication Method for the Test Set
The document does not describe a formal adjudication method (e.g., 2+1, 3+1) for evaluating a test set. The validation activities included "clinical workflow, treatment planning software usability, clinical plan quality / optimization comparison, and dosimetric accuracy," which suggest evaluations were performed by qualified personnel. However, the process for resolving disagreements or establishing a consensus "ground truth" among multiple reviewers is not detailed.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- Was it done? No, the document does not describe a Multi-Reader Multi-Case (MRMC) comparative effectiveness study evaluating the improvement of human readers with AI vs. without AI assistance. The CORVUS system is a treatment planning tool for physicists, dosimetrists, and oncologists, not an AI-assisted diagnostic or interpretation system for human readers in the traditional sense of an MRMC study. Its function is to generate plans, which are then reviewed and approved by clinicians.
- Effect Size: Not applicable, as no MRMC study was performed.
6. Standalone Performance Study
- Was it done? Yes, a standalone performance assessment akin to an "algorithm only" evaluation was performed. The "dosimetric accuracy" assessment ("comparison with medical physics measurements including film and ion chamber measurements") and "clinical plan quality / optimization comparison" directly evaluate the output of the algorithm in generating treatment plans and calculating doses. This inherently assesses the software's performance independent of real-time human interaction during plan generation, although human experts certainly reviewed and evaluated these outputs.
7. Type of Ground Truth Used
The ground truth for evaluating the CORVUS system's performance appears to be a combination of:
- Medical Physics Measurements: "Film and ion chamber measurements" served as the ground truth for dosimetric accuracy. These are standard, highly accurate physical measurements used to verify calculated dose distributions in phantoms.
- Clinical Best Practices/Expert Consensus: "Clinical plan quality / optimization comparison" likely relied on assessment against established clinical guidelines, benchmarks, or expert consensus regarding acceptable dose distributions to targets and sensitive structures.
8. Sample Size for the Training Set
The document does not explicitly state a "training set" sample size for the CORVUS system in the context of AI/machine learning. CORVUS is described as a "semi-automatic planning system" using optimization methods like "simulated annealing and gradient descent," and a "finite size pencil beam (FSPB) algorithm based on the beam characterization of clinically measured data."
This description suggests a rules-based system or an optimization engine that may be calibrated with machine-specific data rather than trained on a large dataset of patient cases in the way that contemporary deep learning models are. If "training" refers to the data used to characterize the treatment machines for the FSPB algorithm:
- Sample Size: Not specified. This would typically involve a proprietary dataset collected by the manufacturer to model the performance of specific linear accelerators or Cobalt-60 units.
9. How the Ground Truth for the Training Set Was Established
Given the nature of the device (a treatment planning system using physics-based algorithms and optimization), the "ground truth" for the calibration/development (if we call it training) of the system's core algorithms (like the FSPB algorithm) would generally be established by:
- Physical Measurements: Extensive physical measurements of radiation beam characteristics (e.g., dose profiles, depth doses, output factors) using dosimeters (ion chambers, film, detectors) on phantoms under various geometries and configurations. This "clinically measured data" is used to characterize the treatment machine's behavior, which in turn informs the FSPB algorithm.
- Mathematical/Physics Models: The algorithms themselves are based on established physics principles, which serve as foundational "ground truth" for the calculations.
§ 892.5050 Medical charged-particle radiation therapy system.
(a)
Identification. A medical charged-particle radiation therapy system is a device that produces by acceleration high energy charged particles (e.g., electrons and protons) intended for use in radiation therapy. This generic type of device may include signal analysis and display equipment, patient and equipment supports, treatment planning computer programs, component parts, and accessories.(b)
Classification. Class II. When intended for use as a quality control system, the film dosimetry system (film scanning system) included as an accessory to the device described in paragraph (a) of this section, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.