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ExacTrac Dynamic is intended to position patients at an accurately defined point within the treatment beam of a medical accelerator for stereotactic radiosurgery or radiotherapy procedures, to monitor the patient position and to provide a beam hold signal in case of a deviations in order to treat lesions, tumors and conditions anywhere in the body when radiation treatment is indicated.

ExacTrac Dynamic is a patient positioning device used in a radiotherapy environment as an add-on system to standard linear accelerators. It uses patient planning and CT data to determine the patient's planned position and compares it via oblique x-ray images to the actual patient position. The calculated correction shift will then be transferred to the treatment machine to align the patient correctly at the machine's treatment position. During treatment the patient is monitored with a surface camera and X-ray to ensure no misalignment due to patient movement.

ExacTrac as a medical device consists of Hardware and Software. Together they are ExacTrac Dynamic.

ExacTrac uses X-ray images acquired with two X-ray tubes and two amorphous silicon detectors to compare the current patient position with the previously planned patient position, based on CT volumetric scans.

The current patient position is monitored using a surface monitoring system.

If necessary, the patient position is corrected using 3rd party patient treatment tables with or without pitch and roll correction possibilities.

Stereotactic radiosurgery (SRS) and Stereotactic Body Radiation Therapy (SBRT) are a highly accurate form of the radiation therapy initially developed to treat small (benign or malignant) tumors and functional abnormalities of the brain.

During treatment a high dose of radiation is delivered within millimeter accuracy to the planned target volume (PTV) while minimizing the dose to the surrounding healthy tissue and organs at risk (OARs). For an accurate dose delivery a precise patient positioning is necessary and an eventual re-positioning of the patient in case of a patient movement during the treatment. The patient positioning system is based on two non-coplanar x-ray 2D image acquisition, that is accurately aligned to the volumetric planning CT (from the plan), the transformation matrix (of the 2D or 3D alignment) is sent to the treatment couch moving the patient to the planned isocenter of the treatment delivery system (Linac). During the treatment delivery the patient movement is monitored via a (3D) surface and a thermal information.

Additionally, an x-ray based position acquisition may be acquired and compared with the planned patient position. Quality assurance procedure are included to ensure a calibration of ExacTrac to itself and to the LINAC

The provided text describes the 510(k) premarket notification for the Brainlab AG ExacTrac Dynamic device. It outlines the device's intended use, description, and performance data.

Here's an analysis of the acceptance criteria and study proving the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document summarizes the essential performance characteristics with specific accuracy requirements.

2. Sample Size and Data Provenance

The document does not specify the sample size used for the test set or the data provenance (e.g., country of origin, retrospective/prospective). It generally states that "Various verification and validation tests were carried out."

3. Number of Experts used for Ground Truth and Qualifications

The document does not provide any information regarding the number of experts used to establish ground truth or their qualifications.

4. Adjudication Method for the Test Set

The document does not mention any adjudication method (e.g., 2+1, 3+1, none) used for the test set.

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

There is no indication that an MRMC comparative effectiveness study was done to evaluate how human readers improve with AI vs. without AI assistance. The device is described as a patient positioning and monitoring system, not primarily an AI-assisted diagnostic tool for human readers. The change was a bug fix, not an AI performance improvement.

6. Standalone (Algorithm Only) Performance

The document describes the device's standalone performance in terms of its ability to calculate shifts, display deviations, and indicate deviations/beam holds with 1mm accuracy and within 3 seconds. The "Performance Data" section directly addresses the device's functionality. The tests mentioned ("Various verification and validation tests") would have assessed this standalone performance.

7. Type of Ground Truth Used

The type of ground truth used is implicitly physical accuracy/measurement. The criteria are based on achieving a 1mm accuracy for positioning and monitoring, and a 3-second response time for the beam hold. This would typically be verified against precisely controlled physical phantoms or established reference measurements rather than expert consensus on images or pathology.

8. Sample Size for the Training Set

The document does not mention any training set sample size. The current submission is for a modification (bug fix) to an existing predicate device (ExacTrac Dynamic 1.0). There is no indication of a new machine learning model being trained or requiring a training dataset.

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

Since there is no mention of a training set or new machine learning model in this specific submission, the method for establishing ground truth for a training set is not applicable or described. The submission focuses on a bug fix and verifying existing functionalities and safety standards.

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