(81 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 deviation 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 addon 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 is monitored with a surface camera and X-ray to ensure no misalignment due to patient movement.
ExacTrac Dynamic 1.1 is a modification of the previously cleared device ExacTrac Dynamic 1.0 that additionally features a Deep Inspiration Breath-Hold (DIBH) functionality to treat breast cancer. This functionality helps correctly position the patient to a deep inspiration breath-hold level and then to monitor this position using surface tracking and x-ray positioning technology. This functionality was not included in ExacTrac Dynamic 1.0. The aim of this technology is to treat the patient only during breath-hold phases where the breast is at a defined position with a maximum distance to critical structures like the heart. Additionally, the surface tracking functionality was extended, which monitors the patient after an initial 3rd party positioning.
The provided text describes the 510(k) submission for Brainlab AG's ExacTrac Dynamic 1.1, a medical device for patient positioning and monitoring during radiation therapy. The key new features in version 1.1 are Deep Inspiration Breath-Hold (DIBH) functionality and an extended "Surface Only" tracking mode.
Here's an analysis of the acceptance criteria and the study proving the device meets them, based on the provided text:
Acceptance Criteria and Device Performance
The document does not present a formal table of acceptance criteria with corresponding reported device performance values. Instead, it states the objectives for the clinical investigation of the new DIBH feature, which can be interpreted as acceptance criteria.
Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Study Objectives for DIBH) | Reported Device Performance (Implied from "All acceptance criteria... were passed") |
|---|---|
| ETD can assist a human eligible for DIBH to reproduce a defined state of deep inspiration breath-hold (DIBH) within +/- 3 mm. | The device successfully met this criterion. |
| Regarding the pre-positioning within the DIBH workflow based on ETD's 3D surface imaging, the surface of a patient - being in state of free-breathing - can be prepositioned with a translational accuracy better than 6 mm. | The device successfully met this criterion. |
Note: The document explicitly states, "All acceptance criteria for the successful completion of the study were passed." This implies that the device performance met or exceeded these criteria. However, specific numerical results or confidence intervals are not provided in this summary.
Study Details
2. Sample Sizes Used for the Test Set and Data Provenance
- Test Set (Clinical Investigation for DIBH):
- Study Population: 13 female subjects. These subjects were divided into:
- Patient Population: Women diagnosed with breast cancer indicated for radiation therapy with DIBH, currently or previously treated with this technique. (Retrospective/Prospective unclear but likely prospective for the study itself).
- Volunteer Population: Healthy women resembling breast cancer patients concerning physiognomy and age, able to perform deep and long DIBHs. (Prospective).
- Data Provenance: The document does not explicitly state the country of origin but implies a single-center clinical investigation ("single-center Clinical Investigation" on page 10). Given the manufacturer is German, it's possible the study was conducted in Germany or a location aligned with their operations. The data collection was prospective for the purposes of this clinical investigation.
- Study Population: 13 female subjects. These subjects were divided into:
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- The document does not provide information on the number of experts or their qualifications used to establish ground truth for the clinical investigation. The "ground truth" for the DIBH study appears to be based on the device's ability to reproduce a target DIBH state and achieve a certain pre-positioning accuracy, which would likely be measured against independent, precise measurements by the study team, rather than expert interpretation of images. However, if any such expert review was involved, it's not detailed here.
4. Adjudication Method for the Test Set
- The document does not describe any adjudication method for the test set. The clinical investigation appears to focus on quantitative measurements of DIBH reproduction and pre-positioning accuracy, rather than subjective assessments requiring adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
- No, an MRMC comparative effectiveness study was not done according to the provided text. The study described focuses on the device's ability to achieve specific accuracy targets for DIBH and pre-positioning, and does not compare human readers with or without AI assistance. The device is a patient positioning and monitoring system, not primarily an image interpretation AI.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
- The clinical investigation evaluates the "surface camera system-based components of the ETD DIBH module" in assisting human patients. While parts of the system operate algorithmically, the "clinical investigation" context implies the system's performance in aiding human execution of DIBH. However, the accuracy tests (e.g., "Accuracy Test: The test objective is to verify that accuracy specifications for positioning and monitoring of ExacTrac Dynamic are not affected by the selected workflow, treatment parameters and different phantom positions.") strongly suggest standalone algorithm performance was evaluated using phantoms in the general "Performance Data" section. Specific standalone results from these phantom tests are not detailed beyond the statement that requirements were met.
7. The Type of Ground Truth Used
- For the DIBH clinical investigation, the ground truth was based on quantitative measurements related to:
- Reproduction of "a defined state of deep inspiration breath-hold" within +/- 3 mm, likely measured by a highly accurate external reference.
- Translational accuracy of pre-positioning "better than 6 mm," also presumably measured against a reference.
- For the "Accuracy Test" mentioned in the Performance Data section, the ground truth was likely established against known, precise phantom positions and deviations.
8. The Sample Size for the Training Set
- The document does not provide any information about the sample size for a training set. This submission is for a modification (ExacTrac Dynamic 1.1) of an existing device (ExacTrac Dynamic 1.0). While the device uses "Deep Inspiration Breath-Hold (DIBH) functionality" which "helps correctly position the patient to a deep inspiration breath-hold level and then to monitor this position using surface tracking and x-ray positioning technology," it doesn't explicitly state that this new functionality is based on a machine learning model that required a specific training set from patient data. If it uses internal algorithms, those would have been developed and tested, but "training set" details are not discussed.
9. How the Ground Truth for the Training Set Was Established
- Since a training set is not explicitly mentioned (as the new features are described as functionalities, not necessarily trained AI models in the conventional sense), no information is provided on how its ground truth was established. If underlying algorithms were "trained," the method would depend on the type of algorithm (e.g., precise measurements on phantoms, or expert annotations if it involved image recognition/assessment).
§ 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.