(140 days)
Leksell Gamma Knife® is a teletherapy device intended for stereotactic irradiation of head structures ranging from very small target sizes of a few millimeters to several centimeters e.g.
- Metastatic tumors
- Recurrent glioblastomas
- Trigeminal neuralgia
- Medically refractory essential tremor
- Orbital tumors
- Ocular tumors
- Optic nerve tumors
- Benign diseases (such as meningiomas, vestibular schwannomas, post-surgical pituitary adenomas, craniopharyngioma, hemangioblastomas, schwannomas, arteriovenous malformations, cavernous malformations, chordomas, glomus tumors, hemangiomas)
- Skull base tumors
- Head and neck tumors (such as unknown primary of the head and neck, oral cavity, hypopharynx, oropharynx, nasopharynx, sinonasal, salivary gland)
- Pediatric tumors (such as glioma, ependymoma, pituitary tumors, hemangioblastoma, craniopharyngioma, meningioma, metastasis, medulloblastoma, nasopharyngeal tumors, arteriovenous malformations, cavernous malformations, skull base tumors)
- Refractory mesial temporal lobe epilepsy in adults
- Refractory epilepsy associated with structural changes such as hamartomas, cerebral cavernous malformations, and arteriovenous malformations (adult and pediatric)
Leksell Gamma Knife® (available models Elekta Esprit, Icon™, and Perfexion™) is a radiosurgery system for use in the stereotactic irradiation of head structures. Surgery is achieved by delivering a prescribed dose as one or more shots of ionizing radiation to the exact site of the target.
The provided FDA 510(k) clearance letter pertains to the Leksell Gamma Knife® (Elekta Esprit, Icon™, Perfexion™) and describes the basis for its substantial equivalence to a predicate device (K222047).
It's important to note that the document outlines the non-clinical performance testing and explicitly states that no animal or clinical tests were performed to establish substantial equivalence for this specific 510(k) submission. This is because the submission primarily focuses on the replacement of obsolete hardware components and a new control system software version to support these components, along with the addition of new indications (Refractory mesial temporal lobe epilepsy in adults and Refractory epilepsy associated with structural changes) that are deemed to fall within the existing intended use and have a favorable benefit-risk profile based on established knowledge of Gamma Knife treatment for certain neurological conditions.
Therefore, the typical structure for describing acceptance criteria and a study proving device performance (especially for AI/ML-driven devices with specific performance metrics like sensitivity, specificity, etc.) is not fully applicable in this context. The acceptance criteria here are more related to functional performance, safety, and maintaining equivalence with the predicate device after hardware and software updates.
However, I can extract the information relevant to what testing was performed and how the device's continued safety and effectiveness were assured.
Acceptance Criteria and Study to Prove Device Meets Acceptance Criteria
Given that this 510(k) focuses on hardware replacement and a software update to support those replacements, rather than the introduction of a novel AI/ML algorithm with specific diagnostic performance metrics, the acceptance criteria are not in the form of typical clinical performance measures (e.g., sensitivity, specificity). Instead, they revolve around functional validation, safety, and maintenance of equivalence to the predicate device.
Key Acceptance Criteria (Inferred from the document):
- Functional Equivalence: The new hardware and software must maintain the same fundamental scientific technology, clinical workflow, and functionality as the predicate device.
- Safety: The device must continue to meet established safety standards and not introduce new or increased risks.
- Performance: The updated system must perform as intended, ensuring accurate and precise stereotactic irradiation.
- Usability: User interface and labeling updates must support safe and effective use.
- Biocompatibility: All new materials in contact with patients must be biocompatible.
Study that Proves the Device Meets the Acceptance Criteria:
The "study" described is a comprehensive set of non-clinical verification and validation activities.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criterion (Inferred) | Reported Device Performance |
|---|---|
| Functional Equivalence | - "New hardware has been introduced to replace old obsolete components. A new control system software version has been introduced to support and enable the new components." |
- "The subject device does not introduce any new clinical requirements or functions."
- "The fundamental technical characteristics... have not changed and are substantially equivalent."
- "The clinical workflow, safety, functionality, and performance is unchanged thus ensuring substantial equivalence." |
| Safety (Risk Control & Compliance with Standards) | - "The change in design required a new risk control to be added to ensure the same level of safety as predicate device and thus ensuring substantial equivalence." - Verification testing performed to IEC 60601-1 series, IEC 62304, ISO 10993 series. |
| Performance (Accuracy & Consistency) | - "Testing in the form of module, integration and system level verification was performed to evaluate the performance and functionality of the new control system and the new hardware against requirement specification." - "Regression test of unchanged functionalities... to ensure that new and updated functionalities did not introduce any undesirable effects." |
| Usability | - "Performance testing, including design and usability validation of the system, has been performed by competent and professionally qualified personnel to ensure that the product fulfils the intended use and user needs." - "The design and usability validation was also made to ensure that the risk control measures associated with functions related to safety (FRS) for the affected functionality... were effective."
- "Updated labeling was in scope of usability evaluation according to IEC 62366-1. The result demonstrate that the labeling support the safe and effective use of the device." |
| Biocompatibility | - "Biocompatibility testing has been performed to ensure that all materials are biocompatible in relation to the use of the device." |
| Substantial Equivalence to Predicate Device (Overall) | - "The performance data demonstrate that the subject device is as safe and effective and performs as well as the predicate devices (K222047)." - "The result of verification and validation as well as conformance to relevant safety standards demonstrate that the Leksell Gamma Knife® meets the established safety and performance criteria and is substantially equivalent to the predicate device." |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: Not explicitly stated as a number of "cases" or "patients" in the context of clinical data. The testing involved system-level verification, module testing, integration testing, and regression testing. This implies testing across the functionality of the device.
- Data Provenance: The nature of the testing is non-clinical performance and functional validation. It's conducted by Elekta Solutions AB (Sweden) as part of their design control and quality system processes. It's not based on retrospective or prospective clinical patient data for efficacy or diagnostic performance.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- Experts: Not applicable in the sense of clinical experts establishing "ground truth" for disease diagnosis or outcome.
- Qualifications: For performance, design, and usability validation, the document states: "Performance testing, including design and usability validation of the system, has been performed by competent and professionally qualified personnel." No specific number or precise qualifications (e.g., "radiologist with 10 years of experience") are provided within this public summary, as this refers to internal quality and engineering validation teams.
4. Adjudication Method for the Test Set
- Adjudication Method: Not applicable. The testing is focused on system functionality, safety, and performance against defined engineering requirements and standards, not on interpreting images or making clinical judgments requiring adjudicated consensus.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
- MRMC Study: No. The document explicitly states: "No animal or clinical tests were performed to establish substantial equivalence with the predicate device." Therefore, no MRMC study comparing human readers with and without AI assistance was conducted for this specific 510(k) submission.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Standalone Performance: No. This device is a radiation therapy system, not an AI diagnostic algorithm. While it has control software, "standalone performance" in the context of AI metrics like sensitivity/specificity for disease detection is not relevant here. The software's performance is integral to the entire system's functionality and safety.
7. The Type of Ground Truth Used
- Ground Truth: For non-clinical validation, the "ground truth" is typically defined by:
- Requirement Specifications: The device's performance is measured against its designed functional and safety requirements.
- Established Standards: Adherence to recognized national and international standards (e.g., IEC 60601, IEC 62304, ISO 10993, IEC 62366-1).
- Predicate Device Equivalence: The gold standard is the documented performance and safety profile of the legally marketed predicate device (K222047).
8. The Sample Size for the Training Set
- Training Set Sample Size: Not applicable. This 510(k) does not describe the development of a novel machine learning algorithm that requires a distinct training set in the AI sense. The software updates are for system control and enabling new hardware, not for learning from vast datasets.
9. How the Ground Truth for the Training Set was Established
- Ground Truth for Training Set: Not applicable, as there is no mention of a training set for an AI/ML algorithm.
§ 892.5750 Radionuclide radiation therapy system.
(a)
Identification. A radionuclide radiation therapy system is a device intended to permit an operator to administer gamma radiation therapy, with the radiation source located at a distance from the patient's body. This generic type of device may include signal analysis and display equipment, patient and equipment supports, treatment planning computer programs, component parts (including beam-limiting devices), and accessories.(b)
Classification. Class II.