(61 days)
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 Xray to ensure no misalignment due to patient movement.
ExacTrac as a medical device consists of Hardware and Software. Together they are ExacTrac Dynamic.
This document is a 510(k) summary for Brainlab AG's ExacTrac Dynamic, a patient positioning device for radiotherapy. It details the device's intended use, description, and performance data to demonstrate substantial equivalence to its predicate device, ExacTrac K120789.
Here's a breakdown of the requested information based on the provided document:
1. A table of acceptance criteria and the reported device performance
The document lists "Essential Performance Characteristics" which are effectively the acceptance criteria for the device's key functionalities. The reported device performance is stated as meeting these criteria.
| Acceptance Criteria (Essential Performance) | Reported Device Performance |
|---|---|
| Positioning: Providing a shift for the patient support system compensating the deviation between patient and planned position, where the shift is calculated with an accuracy of 1mm based on stereo x-ray images. | Shift calculated with an accuracy of 1mm based on stereo x-ray images. |
| Positioning and Monitoring: Display of an X-ray / DRR overlay and indicating a corresponding deviation between patient position and planned position, where the deviation is calculated with an accuracy of 1mm based on stereo x-ray images. | Deviation calculated with an accuracy of 1mm based on stereo x-ray images. |
| Monitoring (Surface Tracking): Indicating a deviation exceeding a predefined tolerance between patient position and a reference position based on surface tracking with an accuracy of 1mm (during irradiation). | Indication of deviation with an accuracy of 1mm using surface tracking. |
| Monitoring (Stereo X-rays): Indicating a deviation exceeding a predefined tolerance between patient position and planned position based on stereo X-rays with an accuracy of 1mm (during irradiation). | Indication of deviation with an accuracy of 1mm using stereo x-rays. |
| Beam Hold: Providing a "Beam hold" signal to the LINAC within 3 sec, if there is a deviation between patient position and reference position exceeding tolerance limits as adjusted by the user. | "Beam hold" signal provided within 3 seconds for deviations exceeding tolerance. |
2. Sample size used for the test set and the data provenance
The document does not explicitly state the sample size used for performance testing (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 on the System, Hardware and Software as applicable."
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
The document does not provide information on the number or qualifications of experts used to establish ground truth for the test set. The performance criteria are defined in terms of measurable physical accuracies (e.g., 1mm accuracy), implying technical measurements rather than expert consensus on diagnostic images.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set
The document does not describe an adjudication method for the test set. Given the nature of the performance criteria (physical accuracy measurements), an adjudication process involving multiple human observers for a "test set" in the context of diagnostic interpretation is not applicable.
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
The document does not describe a multi-reader multi-case (MRMC) comparative effectiveness study. The device focuses on patient positioning and monitoring accuracy, not on diagnostic interpretation aided by AI for human readers. Therefore, an effect size of human reader improvement with or without AI assistance is not relevant to the scope of this submission.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
The entire performance section (Section 4) focuses on the device's (ExacTrac Dynamic) direct performance metrics, such as accuracy of shift calculation, display of deviation, and beam hold signal timing. These are described as functionalities provided by the system itself. Since the device's primary function is automated patient positioning and monitoring based on imaging and feedback, it inherently describes "standalone" performance in terms of its ability to measure and react. The "human-in-the-loop" aspect comes from the user setting tolerances and using the information presented, but the reported accuracies are of the system's measurements and calculations.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
The ground truth for the accuracy measurements (e.g., 1mm accuracy for shifts and deviations) appears to be physical measurement-based (e.g., phantom studies, engineering tolerances). The document states that the system compares the "actual patient position" (measured by X-ray images and surface monitoring) to the "previously planned patient position" (from CT volumetric scans). This implies that the ground truth for evaluating the device's accuracy would involve knowing the true physical position and comparing the device's output to that known position. This is typical for precision mechanical and image registration systems.
8. The sample size for the training set
The document does not mention or describe a "training set" in the context of machine learning or AI. ExacTrac Dynamic is described as using principles of X-ray imaging and comparison with CT data, and surface tracking. While there might be internal algorithms that could benefit from data, the document does not present it as an AI/ML device that undergoes explicit "training" in the modern sense. Therefore, no training set size is provided.
9. How the ground truth for the training set was established
As no training set is mentioned (see point 8), this information is not provided in the document.
§ 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.