(116 days)
The kVCT Imaging Feature is an option within the indications for use of the Radixact Treatment Delivery System. The Radixact Treatment Delivery System is indicated for the delivery of radiation therapy, stereotactic radiotherapy or stereotactic radiosurgery to tumors or other targeted tissues anywhere in the body under the direction of a licensed medical practitioner.
The kVCT Imaging Feature is designed for use with the predicate Radixact Treatment Delivery System last cleared on K161146. The primary functions of the kVCT Imaging Feature are: 1) acquisition of kV x-ray images according to input protocols in concert with other subsystems, 2) correcting 2D images and 3) returning reconstructed 3D images.
The Radixact Treatment Delivery System is a radiation therapy delivery system that provides Image Guided Radiation Therapy (IGRT) using integral megavoltage CT imaging capabilities and delivers helical (rotational) and fixed-angle (non-rotational) radiation therapy to tumors and other targeted tissues.
The provided text describes the 510(k) summary for the Accuray kVCT Imaging Feature for the Radixact Treatment Delivery System. However, it does not contain the specific details of acceptance criteria for diagnostic imaging performance or the results of a study proving the device meets these criteria in the way typically found for AI/CADe devices.
Instead, this document focuses on establishing substantial equivalence to a predicate device (Radixact Treatment Delivery System, K161146) and a reference device (Motion Tracking And Compensation Feature For The Radixact Treatment Delivery System, K182687) by comparing technological characteristics and ensuring safety and performance are equivalent or better. It emphasizes that the kVCT imaging offers improved intrinsic tissue contrast and image quality characteristics compared to that of MVCT imaging (from the predicate).
Therefore, I cannot populate the table and answer all questions in the requested format for acceptance criteria and a study proving performance, as that information is not present. The document explicitly states: "No animal or clinical tests are being submitted to establish substantial equivalence with the predicate device."
However, I can extract the comparative performance specifications between the MVCT Imaging (predicate) and kVCT Imaging (subject device), which are presented as characteristics rather than formal acceptance criteria and study results.
Here's the information that can be extracted, acknowledging the limitations mentioned above:
1. A table of (comparative) performance characteristics:
| Characteristic | Predicate MVCT Imaging (K161146) | Subject kVCT Imaging Feature (K202412) | Analysis/Comment |
|---|---|---|---|
| Imaging Dose | 0.5 - 3.0 cGy (near center of Tomo-Phantom) | 0.6 - 4.3 cGy (CTDIvol, Head) | |
| 0.4 - 2.3 cGy (CTDIvol, Body) | For MVCT Imaging, "Identical. Differences shown are due to additional detail provided and dose characterized in CTDIvol." For kVCT, this feature was "Feature not present" in the predicate, so it's a new capability. Note: The text implies the kVCT energy range offers improved intrinsic tissue contrast and image quality characteristics compared to MVCT, suggesting this imaging dose provides better clinical information. | ||
| Acquisition Trajectory | Helical (for MVCT) | Helical (for kVCT) | For MVCT, "Identical". For kVCT, "Feature not present" in predicate. |
| Slice Spacing | MVCT: 1, 2, 3, 4 and 6 mm reconstruction Intervals | kVCT: 1.2, 1.8, 3.6 mm | For MVCT, "Identical". For kVCT, "Substantially equivalent. The kV Imaging subsystem provides three-dimensional CT images with equivalent or better performance than the predicate device (MVCT)." |
| Spatial Resolution | MVCT: 1.6 mm | kVCT: 1.0 mm (at 2.0 mm intervals) | For MVCT, "Substantially equivalent". For kVCT, "Substantially equivalent. The kV Imaging subsystem provides three-dimensional CT images with equivalent or better performance than the predicate device (MVCT)." (1.0 mm is better than 1.6 mm). |
| Image Size | MVCT: 512 x 512 pixels | kVCT: 512 x 512 pixels | For MVCT, "Identical". For kVCT, "Feature not present" in predicate. |
| Scan Length | MVCT: 135 cm | kVCT: Up to 135 cm | For MVCT, "Identical". For kVCT, "Feature not present" in predicate. |
| Field of View (FOV) | MVCT: 39 cm diameter | kVCT: 25 - 50 cm | For MVCT, "Identical". For kVCT, "Feature not present" in predicate. |
| Image Uniformity | MVCT: Within 25 HU | kVCT: Within 15 HU (Head) | |
| Within 25 HU (Body) | For MVCT, "Identical". For kVCT, "Feature not present" in predicate. The kVCT performance for Head (15 HU) is better than the MVCT (25 HU). | ||
| Image Noise | MVCT: Less than 43 HU | kVCT: Less than 10 HU (Head) | |
| Less than 20 HU (Body) | For MVCT, "Substantially equivalent". For kVCT, "Feature not present" in predicate. The kVCT performance is significantly better (lower HU indicates less noise) than MVCT. | ||
| Contrast Resolution | MVCT: 3% contrast for 30 mm object | kVCT: 1% contrast for 10 mm object (Head) | |
| 2% contrast for 15 mm object (Body) | For MVCT, "Substantially equivalent". For kVCT, "Feature not present" in predicate. The kVCT contrast resolution is significantly better (lower contrast percentage for smaller objects indicates better resolution) than MVCT. | ||
| kV Detector Pixel Pitch | Reference (K182687): 0.4 mm pitch | Subject: 0.15 mm pitch | "Substantially equivalent. The subject device provides the same or better active area with the same or better pixel resolution as compared to the reference device." (0.15 mm is better resolution than 0.4 mm). |
2. Sample size used for the test set and the data provenance:
- The document explicitly states: "No animal or clinical tests are being submitted to establish substantial equivalence with the predicate device."
- Therefore, there is no test set of clinical images described in this document for evaluating diagnostic imaging performance against acceptance criteria. The data provenance is not applicable in this context.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Not applicable as no clinical test set with ground truth established by experts is mentioned.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- Not applicable as no clinical test set is mentioned.
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:
- No MRMC study is mentioned. This device is an imaging feature, not an AI/CADe device designed to assist human readers in interpretation.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- The performance data cited ("Results of verification and validation testing confirm that the use of the kVCT Imaging Feature on the Radixact Treatment Delivery System conforms to design specifications and meets the needs of the intended users") refers to the engineering and technical performance of the imaging system itself, such as spatial resolution, image noise, contrast resolution, uniformity, and radiation dose, as shown in the table. These are intrinsic performance characteristics of the imaging modality, not a "standalone algorithm" performance in the context of an AI/CADe device.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For the technical performance characteristics listed (e.g., spatial resolution, image noise), the ground truth is typically established through phantom studies and metrology, comparing measured values against engineering specifications rather than clinical ground truth like pathology or expert consensus.
8. The sample size for the training set:
- Not applicable as this document does not describe an AI/CADe device that uses a training set of images.
9. How the ground truth for the training set was established:
- Not applicable.
§ 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.