(29 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.
Here's a breakdown of the acceptance criteria and the study details for the CORVUS device, based on the provided FDA 510(k) summary:
The CORVUS device is a radiation treatment planning system. The supplied document focuses on demonstrating substantial equivalence to a predicate device (CORVUS 14) rather than a direct clinical performance study against specific acceptance criteria for diagnostic accuracy in the typical sense of AI/ML devices.
Therefore, the acceptance criteria and study detailed below are primarily centered around dosimetric accuracy, software functionality, and compliance with relevant standards, which are the key performance indicators for a treatment planning system seeking 510(k) clearance.
1. Table of Acceptance Criteria and Reported Device Performance
Given that this is a 510(k) submission for a treatment planning system and not a diagnostic AI device, the "acceptance criteria" are generally related to dosimetric accuracy and software performance compared to established benchmarks or the predicate device.
| Acceptance Criteria Category | Specific Acceptance Criteria (Inferred from documentation) | Reported Device Performance |
|---|---|---|
| Dosimetric Accuracy | - Treatment plan calculations (dose distribution) align with medical physics measurements. |
- Calculations for Cobalt-60 based Forward Planning align with expected accuracy (implied by adding this new feature).
- Pencil-beam algorithm and dose calculation options (homogeneous, EPL) maintain accuracy. | - "The accuracy of treatment plans was evaluated through comparison with medical physics measurements 2D array and ion chamber measurements."
- The submission states that the "verification and validation results demonstrate that the CORVUS 15 system met its design requirements and specifications."
- The fundamental scientific technology and intended use/indications are unchanged from the predicate, implying similar dosimetric performance for existing features. |
| Software Functionality | - All device functionalities work as per its intended use. - Risk mitigation is ensured for software.
- Conforms to required software standards (IEC 62304, IEC 62366-1, IEC 62083).
- New features (Cobalt-60 Forward Planning) function correctly and safely. | - "Design verification and validation testing was performed to ensure that the device functionality works as per its intended use, all risks are mitigated, is substantially equivalent, and the product conforms to the required standards."
- "The verification activities included system tests, module tests, anomaly verification, code reviews, and run-through integration tests."
- "The validation activities included clinical workflow, treatment planning software usability, dosimetric accuracy, and import-export." |
| Substantial Equivalence | - No new issues of safety or effectiveness are raised compared to the predicate device (CORVUS 14). - Intended use and indications for use remain substantially similar or unchanged.
- Fundamental technical characteristics are the same. | - "The fundamental scientific technology of the CORVUS 15 with respect to its predicate device (CORVUS 14) system has not changed. The intended use and indications for use of the device have not changed. Based upon the performance testing results for CORVUS 15 (as detailed in the submission), the system raises no new issues of safety or effectiveness." |
2. Sample Size Used for the Test Set and Data Provenance
The document does not specify a "test set" in the sense of a dataset of patient cases used for clinical efficacy as would be seen for a diagnostic AI. Instead, the testing focuses on system verification and dosimetric validation.
- Sample Size for Test Set: Not explicitly stated in terms of patient cases. The testing involved "medical physics measurements 2D array and ion chamber measurements." This typically involves a set of phantoms or carefully controlled geometric setups, but the number of such measurements or scenarios is not provided.
- Data Provenance: Not applicable in the context of patient data. The "measurements" would be generated in a lab setting, not from patients.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
- Number of Experts: Not explicitly stated. The "accuracy of treatment plans was evaluated through comparison with medical physics measurements." This implies evaluation by medical physicists.
- Qualifications of Experts: The involvement of "medical physicists" is mentioned. Their specific years of experience or board certifications are not provided in this summary.
4. Adjudication Method for the Test Set
Not applicable. This is not a study requiring adjudication of expert interpretations of images or patient outcomes. The "ground truth" for dosimetric accuracy would be independent physical measurements.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No. This type of study is typically performed for diagnostic or AI-assisted interpretation devices to compare human performance with and without AI assistance. CORVUS is a treatment planning system, and its evaluation focuses on the accuracy of its calculations and software functionality, not on improving human reader performance in interpreting images.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, in the context of a treatment planning system. The "dosimetric accuracy" testing evaluates the algorithm's output (calculated dose distributions) against physical measurements, which is an algorithm-only evaluation. While the system is used by humans (medical physicists, dosimetrists, radiation oncologists), the core dose calculation component performs its function algorithmically, and its output is verified independently.
7. The Type of Ground Truth Used
The ground truth used for evaluating dosimetric accuracy was medical physics measurements (2D array and ion chamber measurements). This represents a physical, objective standard for verifying dose distribution accuracy.
8. The Sample Size for the Training Set
Not applicable. CORVUS is a rule-based or physics-based treatment planning system, not a machine learning (ML) or artificial intelligence (AI) device that typically requires a large 'training set' of data in the common sense for algorithm development. Its algorithms are based on established physics models and mathematical optimization techniques.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as there isn't a "training set" in the context of machine learning. The algorithms are built upon fundamental physics and mathematical principles, and characterized/calibrated using machine-specific data (e.g., beam data from a linear accelerator). This characterization data is not a "ground truth for training" in the AI/ML sense but rather input parameters that define the physical behavior of the treatment machine.
§ 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.