(90 days)
The Elekta X-Ray Volume Imaging system, XVI, is an electronic imaging device (EID), designed to be used with the Elekta range of medical linear accelerators and intended to be used as part of the radiation therapy treatment process for single or multiple fractions, of static and/or dynamic treatments, in gated or un-gated deliveries, in all areas of the body where such image guidance is determined by a licensed physician.
It provides real-time 2D, 3D & 4D image guidance before, during and after treatment delivery, and is intended to support confirmation of patient positioning, monitoring and management of internal motion, and decision making in response to target position, size. shape and displacement resulting from organ deformation and anatomical movement in relation to surrounding critical structures.
X VI facilitates precise and accurate dose placement, and patient set-up correction, through visualization of internal anatomy including target, critical structures and soft tissue with or without the use of implanted markers.
Symmetry™ is a software option within XVI that can be used to acquire and display volumetric images of sequential phases of the breathing cycle for the evaluation of respiration induced motion, to assist in identification of appropriate target locations within anatomical structures in motion.
The Elekta digital linear accelerator can be used for treatment that includes but is not limited to malignant and benign brain tumors, brain metastases, spine lesions treated using SRS, squamous cell carcinoma of the head and neck, lung, breast, pancreatic, hepatic malignancies treated using SBRT, prostate, and bone metastases.
This Traditional 510/k) describes modifications made to the XVI kilo-voltage imaging accessory of the Elekta range of digital linear accelerators. The primary reason for these modifications is to further enhance the imaging tools to support the monitoring and management of motion, by allowing visualization of tumor and surrounding critical structures during treatment delivery.
Improvements have also been made to the operator interface connectivity with other systems to support distributed workflow and in the provision of licensable options to tailor individual features.
The XVI system consists of a kV radiation source mounted onto the linac gantry drum and a kV radiation image detector. Incorporation of the kV imaging system onto the same structure as the treatment system allows high quality images of the patient anatomy to be acquired at the point of treatment and their content to be spatially related to the planned MV treatment, as previously cleared under Control Number (K100115)
There has been no change made to the underlying technological characteristics of the product.
Here's a breakdown of the acceptance criteria and study information for the Elekta XVI R5.0, based on the provided document:
This 510(k) summary (K131965) for Elekta XVI R5.0 does not contain specific acceptance criteria with numerical targets and reported device performance values nor details of a formal clinical study to prove these criteria. It focuses on demonstrating substantial equivalence to predicate devices and describes non-clinical performance testing.
Therefore, many of your requested points cannot be fully answered from this document. I will fill in what can be inferred or is explicitly stated and note where information is absent.
Acceptance Criteria and Device Performance
This document does not specify quantitative acceptance criteria (e.g., in terms of sensitivity, specificity, accuracy, precision, or detection rates) for the XVI R5.0. Instead, it relies on demonstrating that the device's functionality and performance are substantially equivalent to its predicates and that it meets internal requirement specifications and voluntary consensus safety standards.
| Acceptance Criteria (Inferred from functionality claims) | Reported Device Performance (as stated or inferred) |
|---|---|
| Visualize bony anatomy on image | Performance is "No Change" (to predicate behavior) |
| Visualize soft tissue on image | Performance is "No Change" (to predicate behavior) |
| Visualize implanted markers in patient | Performance is "No Change" (to predicate behavior) |
| Image patient in treatment position | Performance is "No Change" (to predicate behavior) |
| 2D image acquisition | Performance is "No Change" (to predicate behavior) |
| Stereoscopic Imaging | Performance is "Enhanced" |
| 3D image acquisition | Performance is "No Change" (to predicate behavior) |
| 4D image acquisition | Performance is "No Change" (to predicate behavior) |
| Low (kV) radiation dose required | Performance is "Low (kV)" |
| 3D Volumetric Registration | Performance is "No Change" (to predicate behavior) |
| Dual Registration | Performance is "No Change" (to predicate behavior) |
| 4D Volumetric Registration | Performance is "No Change" (to predicate behavior) |
| Intra-fraction Imaging | Performance is "Yes" (new capability) |
| Conformance to applicable technical design specification | Met |
| Safety & Effectiveness | Achieved |
| Compliance to voluntary consensus safety standards | Achieved (e.g., IEC 60601 series, IEC 62304, etc.) |
Study Details
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Sample size used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective):
- Sample Size: Not specified. The document mentions "clinically representative conditions" and "testing... at hospital sites," but no specific number of patients, cases, or images is provided for any test set.
- Data Provenance: Not specified. The company is based in the UK, but where the "hospital sites" are located for testing is not mentioned. It is unclear if data was retrospective or prospective.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of experts: Not specified.
- Qualifications: "Competent and professionally qualified personnel" performed validation, but their specific qualifications (e.g., radiologists, oncologists, number of years experience) are not detailed.
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Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- Not specified. The document does not describe any expert adjudication process for establishing ground truth for a test set.
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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:
- Not performed/Not applicable. This document describes a device that provides image guidance for radiation therapy, not an AI-assisted diagnostic tool for human readers in the traditional sense. It's an imaging accessory for a linear accelerator. There is no mention of an MRMC study comparing human reader performance with and without this device's assistance.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Partially. The product itself is an "electronic imaging device (EID)" and its functions (image acquisition, 3D/4D registration, etc.) operate algorithmically. Non-clinical performance testing validated the "performance and functionality of the new and existing features against the requirement specification," which implies testing the algorithm's standalone capabilities. However, clinical performance in terms of patient outcomes or diagnostic accuracy without human intervention is not described, as the device is intended for human use "as part of the radiation therapy treatment process." The term "standalone" in this context might refer to testing the imaging and processing capabilities independently of patient treatment.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc):
- Not explicitly stated. Given the context of medical device testing for functionality and safety, ground truth for validation likely refers to:
- Technical specifications/phantoms/known values: For verifying image quality, geometric accuracy, registration capabilities.
- Clinical observation/expert verification during "clinically representative conditions": For assessing whether the visualization and motion management features operate as intended for patient positioning and internal motion.
- There is no mention of pathology, post-treatment outcomes data, or a formal expert consensus process as "ground truth" for a performance study.
- Not explicitly stated. Given the context of medical device testing for functionality and safety, ground truth for validation likely refers to:
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The sample size for the training set:
- Not applicable. This document describes a medical imaging device that acquires and processes images, not a machine learning model that requires a training set in the conventional sense (e.g., for classification or detection tasks). While the device's algorithms would have been developed and refined, the document does not refer to a "training set" for the purpose of a regulatory submission.
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How the ground truth for the training set was established:
- Not applicable (as per point 7).
Summary of Limitations in the Provided Document:
The provided 510(k) summary is typical for a device demonstrating substantial equivalence, especially for modifications to an existing device (XVI R4.5) and expanding functionalities already present in predicate devices (Varian TrueBeam and Brainlab ExacTrac Vero). It emphasizes:
- Technological characteristics: Demonstrating that changes are minor or equivalent to predicates.
- Non-clinical performance testing: Verifying that the device meets its own functional and safety specifications.
- Compliance with standards: Adhering to relevant industry and safety standards.
It does not include the detailed clinical study data, quantitative acceptance criteria, or robust ground truth methodologies that would be expected for a novel device or an AI/CADe (Computer-Aided Detection) device undergoing a de novo or PMA pathway, or for an AI device where improved diagnostic performance is the primary claim.
§ 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.