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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: 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 an analysis of the acceptance criteria and study information for the CORVUS Radiation Therapy Planning System, based on the provided document:

This document describes a premarket notification (510(k)) for the CORVUS Radiation Therapy Planning System (K151469), which is an accessory to medical devices of Major Level of Concern. The submission focuses on the upgrade from CORVUS 09 to CORVUS 2011, primarily adding support for Cobalt-60 based external beam radiation treatment planning (Gamma Tomotherapy) and updated operating system/hardware.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria provided are mostly qualitative (e.g., "clinically acceptable," "similar") or defined by pass/fail thresholds for dosimetric accuracy.

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size: The document does not explicitly state the numerical sample size for patient cases or plans used in the test sets for most clinical validation tests. It mentions "various pencil beam sizes" (Test 4), "multiple test results" (Test 4), and "all Cobalt validation plans" (Test 8), which are not specific numbers. For Test 1 (Linac Dose Equivalence) and Test 2 (Clinical Comparison), it refers to "the same patients" and "treatment plans created for Cobalt treatment," but no specific count of patients or plans is given.
• Data Provenance: The document does not specify the country of origin of the data. It also does not explicitly state whether the data was retrospective or prospective. Given the context of clinical comparison and re-calculation, it is likely retrospective, using existing patient data or phantom measurements, but this is not definitively stated.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts

• The document mentions that the CORVUS system is "designed to allow medical physicists, dosimetrists, and radiation oncologists to create conformal treatment plans." And that "It is the physician's responsibility to verify that the dose distributions... are appropriate for a particular patient."
• However, for the specific validation studies on the test set, the document does not explicitly state the number of experts or their qualifications used to establish the "ground truth" or to review the clinical acceptability of plans. The "clinical acceptability" (Test 2) implies expert review, but details are not provided. The dosimetric accuracy tests (Tests 3, 4, 8) rely on direct physical measurements (film and ionization chambers) rather than expert consensus as the ground truth.

4. Adjudication Method for the Test Set

• The document does not describe any explicit adjudication method for expert review (e.g., 2+1, 3+1). For the dosimetric tests, the adjudication is based on direct measurement comparison against defined physical thresholds (e.g., 4% / 4mm).

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• No, a MRMC comparative effectiveness study was not done as described in the document. The studies were primarily focused on comparing the CORVUS 2011 algorithm's output against:
  • Previous version (CORVUS 09) outputs (Tests 1, 2, 7)
  • Physical measurements (Tests 3, 4, 8)
  • Expected computational outcomes (Test 5)
• There is no mention of human readers, their performance without AI (the planning system itself), or an effect size of improvement with AI assistance. The system is a planning tool, not an AI for interpretation or diagnosis that would augment human review in that manner.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

• Yes, the studies are largely standalone in terms of the algorithm's performance. The tests primarily evaluate the calculations and outputs of the CORVUS 2011 system itself (dose equivalence, dosimetric accuracy, consistency of calculations, transfer of data).
• While the system is a "semi-automatic planning system" that "suggests a plan" which a "clinician then reviews and approves," the validation tests described focus on the accuracy and equivalence of the generated plans and calculations themselves, rather than the overall human-in-the-loop workflow's effectiveness. Test 2 (Clinical comparison) does allude to "clinical efficacy" and "clinical acceptability" but without specifying a human-in-the-loop scenario. The dosimetric tests are purely algorithmic output vs. physical measurement.

7. Type of Ground Truth Used

• Mixed:
  • For dosimetric accuracy (Tests 3, 4, 8): Physical measurements using EDR2 film and ionization chambers (0.125 cc chamber, CC01 ionization chamber). This is a objective, empirical ground truth.
  • For clinical comparisons and equivalence (Tests 1, 2, 7): The ground truth is established by comparison to the predicate device's output (CORVUS 09) and expert consensus on "clinical acceptability" or "clinical similarity," though the specifics of this expert consensus are not detailed.
  • For dose comparison consistency (Test 5) and system transfer (Test 6): Expected computational outcomes and predefined data formats (DICOM RT) serve as the ground truth.

8. Sample Size for the Training Set

• The document does not provide any information about the sample size for a training set. CORVUS is described as a "semi-automatic planning system" using "optimization methods including simulated annealing and gradient descent," and dosage is calculated "using a finite size pencil beam (FSPB) algorithm based on the beam characterization of clinically measured data." This suggests a model-based approach with measured beam data, rather than a machine learning model that would typically have a "training set" in the modern sense. The "clinically measured data" for beam characterization itself would be a foundational dataset, but its size is not specified as a "training set."

9. How the Ground Truth for the Training Set Was Established

• As a "training set" in the modern AI/ML sense is not explicitly mentioned, the concept of establishing ground truth for it is not addressed. The "beam characterization of clinically measured data" for the FSPB algorithm would have its ground truth established through direct physical measurements of radiation beam properties.

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The ViewRay System, with magnetic resonance imaging capabilities, is intended to provide stereotactic radiosurgery and precision radiotherapy for lesions, tumors, and conditions anywhere in the body where radiation treatment is indicated.

The ViewRay™ System for Radiation Therapy is a single medical device that combines a magnetic resonance imaging system for image guidance, with a cobalt-60 radiation delivery system. The system is designed so that the imaging and radiotherapy fields of view coincide, permitting imaging of the patient at the radiotherapy isocenter before and during treatment. These imaging and radiation delivery systems are designed to operate together as the ViewRay System, for accurate, targeted administration of radiation therapy. The ViewRay System is used with the ViewRay Treatment Planning and Delivery System (TPDS) (K102915, FDA clearance 1/12/11).

The magnetic resonance imaging system (MRIS) of the ViewRay System can be used by the clinician to perform three (3) different functions before and during the treatment of a patient. A trained clinician may choose to perform all, some, or none of the functions. These 3 functions are:

• Treatment planning the images from the ViewRay MRIS can be used to perform pre-treatment and on-table planning.
• Patient positioning Fast pilot or planning volumetric images can be used to position the patient.
• Treatment gating (soft tissue tracking)- If the prescribing clinician employs this feature during therapy, planar MR images (in a single plane or in 3 planes) are taken continuously during therapy delivery, to control the beam based on anatomy motion.

The ViewRay radiation delivery system (RDS) consists of:

• Radioactive cobalt-60 sources
• Source shielding heads and movement mechanism
• Gantry and base
• Multi-leaf collimators
• Radiation therapy control system
• User console

The sealed cobalt-60 sources are housed in source-shielding heads made of tungsten alloy and depleted uranium encased with stainless steel. The heads are mounted on a ring gantry located between the gap in the MRIS magnets. The sources can be positioned for therapy (BEAM ON), standby (BEAM HOLD) and shielding (BEAM OFF) by the source movement mechanism. The beams from the sources are shaped to conform to the target using double focused multi-leaf collimators. The radiation therapy interfaces with the radiation treatment planning, imaging, gating, and dose calculation functions by means of the radiation therapy control system (RTCS). This system is the central point of control and is designed to provide fail-safe operation of the ViewRay System. The RTCS includes the Radiation Therapy Controller (RTC) and the Auxiliary Controller (AUXC). The AUXC provides secondary monitoring of the ViewRay System safety functions in the event of an RTC failure. The ViewRay System records patient information, treatment plans, dose administered during each fraction, the accumulated dose, imaging data, and system performance during treatment.

The provided text is a 510(k) Premarket Notification Summary for the ViewRay™ System for Radiation Therapy. This type of submission focuses on demonstrating substantial equivalence to a predicate device, rather than providing detailed clinical study results with specific performance metrics against acceptance criteria in the way a PMA or de novo submission might.

Therefore, much of the requested information regarding acceptance criteria, specific performance metrics, sample sizes, ground truth establishment, expert qualifications, and MRMC studies is not present in this document.

Here's a breakdown of what can be extracted and what is missing:

1. Table of Acceptance Criteria and Reported Device Performance

• IEC 60601-1 (2.0 Edition)
• IEC 60601-2-33 (3.0 Edition)
• IEC 60601-2-11 (2.0 Edition) | Conformed with all applicable sections of IEC 60601-1 (2.0 Edition), IEC 60601-2-33 (3.0 Edition) and IEC 60601-2-11 (2.0 Edition) |
  | Substantial equivalence to predicate device (Trilogy Mx™ Radiotherapy Delivery System K092871) | System performance was found to be equivalent in function to the predicate device. |

Note: The document describes "Design Verification testing" as the study proving the device meets these criteria.

2. Sample size used for the test set and the data provenance

• Sample size: Not specified. The document states "Design Verification testing was performed," but does not detail the number of patients, phantoms, or test cases used.
• Data provenance: Not specified. As a 510(k) submission primarily focused on engineering and functional testing, clinical data provenance is not typically detailed in this section unless a specific clinical study for performance was required beyond substantial equivalence.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

• Number of experts: Not specified.
• Qualifications of experts: Not specified.
  • Rationale: This document describes verification testing against design requirements and standards, not a clinical study requiring expert-established ground truth for performance evaluation in the typical sense of diagnostic or prescriptive AI algorithms. The "ground truth" here would be the established engineering specifications and standard requirements.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set

• Adjudication method: Not specified.
  • Rationale: As above, this type of adjudication is typically for clinical performance evaluation (e.g., grading images) and not for engineering verification testing described here.

5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

• MRMC study: No, a multi-reader, multi-case comparative effectiveness study was not explicitly mentioned or indicated in the provided text.
• Effect size: Not applicable, as no MRMC study was reported.
  • Rationale: The ViewRay system is a medical device combining imaging and radiation delivery for treatment, not an AI-assisted diagnostic tool for human readers in the way an MRMC study would typically evaluate. The text describes the system's capabilities (e.g., continuous imaging for soft tissue tracking) but not as an "AI assistance" to human readers.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

• Standalone performance: Yes, the device itself underwent "Design Verification testing" to show conformance to design requirements and standards. This testing evaluates the device's inherent functionality (imaging quality, radiation delivery accuracy, safety features, etc.) as a standalone system. However, it's not an "algorithm-only" standalone performance in the context of an AI device but rather the integrated system's performance. The document focuses on the system's performance against engineering metrics.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

• Type of ground truth: The "ground truth" for the verification testing described would primarily be:
  • Engineering specifications and design requirements: The device was tested to ensure it met its pre-defined design parameters.
  • Applicable international standards (IEC 60601 series): The device's performance was compared against the requirements set by these medical device standards.
  • Predicate device's established performance: The ViewRay system's function was compared to the Trilogy Mx™ System to demonstrate substantial equivalence, meaning the predicate's performance served as a benchmark for equivalence.

8. The sample size for the training set

• Sample size: Not applicable.
  • Rationale: This document does not describe the development of an "AI algorithm" in the sense that would require a distinct training set for machine learning. The ViewRay system is a complex integrated medical device, and its functional verification does not typically involve training a machine learning model.

9. How the ground truth for the training set was established

• Ground truth establishment: Not applicable.
  • Rationale: As there is no mention of a training set for an AI algorithm, the concept of establishing ground truth for such a set is not relevant to this document's content.

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