(46 days)
ExacTrac Vero is intended to be used in conjunction with the MHI-TM2000 radiation therapy linear accelerator system manufactured by Mitsubishi Heavy Industries, Ltd.
ExacTrac Vero uses the images received from the MHI-TM2000 linear accelerator for analyzing the current patient position and calculating - when applicable - a necessary correction shift. The correction shift is then exported to the MHI-TM2000 linear accelerator.
ExacTrac Vero uses stereoscopic x-ray or cone beam CT registration and optical tracking of infrared reflective markers in order to localize and correct the patient position before and during treatment.
Optionally ExacTrac Vero provides position data for the pan/tilt motion of the TM2000 gantry head to the MHI-TM2000 controller for continuous alignment of the beam orientation with a moving target. The position data is based on target detection via X-ray imaging and IR tracking of external surrogate markers.
ExacTrac Vero is a patient positioning and monitoring system for the MHI-TM2000 Linear Accelerator System by Mitsubishi Heavy Industries Ltd. providing the following main features:
- Patient positioning based on comparison between X-ray images and . CT data provided by a treatment planning system.
- . Patient positioning based on comparison between Cone Beam CT data and CT data provided by a treatment planning system.
- Optionally providing position data for the pan/tilt motion of the MHI-. TM2000 gantry head controller for continuous alignment of the beam orientation with a moving target. The position data is based on infrared tracking of external surrogate markers and the calculated correlation between those external markers and implanted marker positions as detected in X-ray images.
- Monitoring of the patient position during treatment. .
The following main functionalities were already available for the predicate device ExacTrac 3td Party (K072046) and have been found to be substantially equivalent:
- Patient positioning based on comparison between X-ray images, provided by an Imaging Device of the MHI-TM2000 Linear Accelerator System, and CT data provided by a treatment planning system.
- . Patient positioning based on comparison between Cone Beam CT data, provided by an Imaging Device of the MHI-TM2000 Linear Accelerator System, and CT data provided by a treatment planning system.
- Both modalities can be based on anatomical landmarks or implanted . markers.
- . Monitoring of the patient position during treatment.
The new functionality for treatment of moving targets was found to be substantially equivalent with the predicate device Synchrony® Respiratory Tracking System (K120233) by Accuray Inc.
This new feature provides position data for the pan/tilt motion of the MHI-TM2000 gantry head controller for continuous alignment of the beam orientation with a moving target. The position data are based on infrared tracking of external surrogate markers and the calculated correlation between those external markers and implanted marker positions as detected in X-ray images.
Changes to Predicate Device ExacTrac 3"d Party (K072046):
ExacTrac Vero introduces a new functionality that provides in combination with the MHI-TM2000 linear accelerator the option of aligning the treatment beam with moving targets. This new function provides position data for the pan/tilt motion of the MHI-TM2000 gantry head controller for continuous alignment of the beam orientation with the breathing induced movement of the target.
The provided K122451 submission for ExacTrac Vero does not contain a detailed study report with specific acceptance criteria, reported performance, or sample sizes for clinical validation in the format requested. The document outlines general verification and validation methods and concludes that the system is safe and effective based on these procedures, but it does not provide quantitative results against predefined acceptance criteria.
The submission primarily focuses on establishing substantial equivalence to predicate devices (ExacTrac 3rd Party and Synchrony® Respiratory Tracking System) for its functionalities, including patient positioning and monitoring, and a new feature for continuous alignment with moving targets.
However, based on the type of information typically expected for such submissions and what is generally associated with "acceptance criteria" and "device performance" in general medical device development, and what can be inferred from the text, here's an attempt to structure the answer, acknowledging the limitations of the provided document.
1. Acceptance Criteria and Reported Device Performance
The provided document does not explicitly list quantitative acceptance criteria or detailed reported device performance metrics in a tabular format. The submission states that "The verification and validation proves the safety and effectiveness of the system," implying that the device met its internal design and performance specifications, which would include accuracy and precision.
Given the nature of the device (a patient positioning and monitoring system for radiation therapy), typical acceptance criteria would relate to:
- Localization Accuracy: The precision with which the system can determine the position of the target (e.g., tumor, anatomical landmark, implanted marker).
- Correction Shift Accuracy: The accuracy of the calculated correction shift to be applied to the linear accelerator.
- Tracking Accuracy (for moving targets): For the new functionality, the accuracy of continuously tracking a moving target and aligning the beam.
- Latency: The time delay between detecting a position and providing a correction.
- Reliability/Reproducibility: Consistency of measurements.
Without explicit numbers, we can only infer that the device met internal thresholds for these types of performance metrics that are typically aligned with clinical requirements for precision radiation therapy.
| Acceptance Criteria (Inferred from device type) | Reported Device Performance (Not explicit in document) |
|---|---|
| Localization Accuracy | Met internal specifications (implied) |
| Correction Shift Accuracy | Met internal specifications (implied) |
| Tracking Accuracy (for moving targets) | Substantially equivalent to predicate (implied good performance) |
| Latency | Met internal specifications (implied) |
| Reliability/Reproducibility | Met internal specifications (implied) |
2. Sample Size Used for the Test Set and Data Provenance
The document states that the clinical evaluation used:
- "Simulated treatment of anthropomorphic human-bone phantoms within a simulated clinical environment."
- "Retrospective analysis of correlation between breathing and tumor motion."
- "Analysis of existing x-ray image sets acquired during routine clinical use of predicate devices."
Sample Size:
- Phantoms: The number of phantoms used is not specified.
- Retrospective Analysis: The size of the dataset used for retrospective analysis of breathing and tumor motion, and the number of existing X-ray image sets from predicate devices, are not specified.
Data Provenance:
- Phantoms: Simulated clinical environment (location not specified, likely internal to Brainlab AG or a collaborator).
- Retrospective Analysis: Originated from "routine clinical use of predicate devices." The country of origin is not specified, but given Brainlab AG is based in Germany, it's possible this includes European data.
- Prospective/Retrospective: The analysis of phantom data would be considered a form of prospective testing in a simulated environment. The analysis of "existing x-ray image sets acquired during routine clinical use of predicate devices" and "retrospective analysis of correlation between breathing and tumor motion" are explicitly retrospective.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
The document does not specify the number of experts used to establish ground truth or their qualifications for any of the clinical evaluation methods (phantoms, retrospective analysis, or X-ray image sets).
In phantom studies, the "ground truth" is typically established by the known physical properties and precise placement of structures within the phantom, measured independently. For retrospective image analysis, ground truth would typically be established by expert review (e.g., radiation oncologists, radiologists, medical physicists), but this is not detailed.
4. Adjudication Method for the Test Set
The document does not describe any adjudication method (e.g., 2+1, 3+1, none) for the test set or any part of the clinical evaluation. The evaluations appear to be conducted via technical analyses and simulations rather than multi-reader clinical interpretation scenarios.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
The document does not mention or describe a Multi-Reader Multi-Case (MRMC) comparative effectiveness study. There is no information regarding a study comparing human readers with and without AI assistance, or any effect size related to AI improvement. The device itself is a positioning and monitoring system, not primarily an AI-assisted diagnostic or interpretation tool for human readers in the traditional sense of an MRMC study.
6. Standalone (Algorithm Only) Performance Study
The studies described ("Simulated treatment of anthropomorphic human-bone phantoms," "Retrospective analysis of correlation between breathing and tumor motion," "Analysis of existing x-ray image sets acquired during routine clinical use of predicate devices") appear to evaluate the standalone performance of the ExacTrac Vero system. These evaluations focus on the system's ability to accurately perform its functions (patient positioning, correction calculation, and tracking) in a simulated and retrospective context, independent of human interaction during the measurement process, before the human operator would decide to apply a correction.
7. Type of Ground Truth Used
The ground truth for the clinical evaluation was established using:
- Physical Phantom Data: For the "simulated treatment of anthropomorphic human-bone phantoms," the ground truth would be based on the known, precise physical locations of structures and markers within the phantoms.
- Retrospective Clinical Data: For the "retrospective analysis of correlation between breathing and tumor motion" and "analysis of existing x-ray image sets," the ground truth would likely refer to the clinically established information about patient/tumor motion from the original clinical trials or routine use where these images were acquired. This could implicitly involve expert consensus or established treatment plans, but the document does not elaborate.
8. Sample Size for the Training Set
The document does not specify any sample size for a training set. The descriptions of the verification and validation methods focus on testing the developed system, rather than describing the development and training of machine learning models with explicit training datasets. If the system uses machine learning components, the training data is not detailed in this submission.
9. How the Ground Truth for the Training Set Was Established
Since no training set is described or mentioned, the method for establishing ground truth for a training set is not provided.
§ 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.