(86 days)
Elekta Unity using Magnetic Resonance Imaging is indicated for radiation therapy treatments and stereotactic radiation treatments of malignant and benign diseases anywhere in the body as determined by a licensed medical practitioner in accordance with a defined treatment plan. Elekta Unity is intended for use with the compatible Treatment Planning and Oncology Information Systems.
The Elekta Unity 1.5T MR scanner is a magnetic resonance imaging system that produces cross-sectional images in any orientation of the internal structure of the whole body before, during, and after the radiotherapy treatment. When interpreted by a trained physician magnetic resonance images acquired before, during, and after the radiotherapy treatment yield information that can be useful in diagnosis and may assist therapy planning, patient positioning and treatment delivery related to radiation oncology.
Elekta Unity is a multifunctional digital linear accelerator designed to assist licensed medical practitioners in the delivery of ionizing radiation to defined volumes (e.g. malignant and benign tumors). Elekta Unity is capable of both intensity modulated radiation therapy (IMRT) and image guided radiation therapy (IGRT).
The Elekta Unity 1.5T MRI scanner is a magnetic resonance imaging sub-system that produces cross-sectional images in any orientation of the internal structure of the whole body before, during, and after the radiotherapy treatment.
When interpreted by a trained physician the images acquired before, during, and after the radiotherapy treatment yield information that can be useful in diagnosis and may assist therapy planning, patient positioning and treatment delivery related to radiation oncology.
In addition to the MRI sequences cleared with the predicate device, the current Elekta Unity configuration has the ability to generate images using following techniques, before, during or after treatment for Off-line review:
- Single-shot EPI diffusion imaging (DWI) with 3 diffusion directions and up to 16 b-values.
- . Diffusion imaging processing with automatic generation of the ADC and/or eADC maps.
Here's a breakdown of the acceptance criteria and the study details for the Elekta Unity device, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Criteria Category | Acceptance Criteria (Predicate Device) | Reported Device Performance (Current Device) | Comparison |
|---|---|---|---|
| Radiation Source/Beam | 7MV Bremsstrahlung X- Rays Produced by Linear Accelerator | 7MV Bremsstrahlung X- Rays Produced by Linear Accelerator | Same |
| Method of IMRT | MLC based cone-beam delivery | MLC based cone-beam delivery | Same |
| Collimation | Field shaping, Multi Leaf Collimator (MLC) | Field shaping, Multi Leaf Collimator (MLC) | Same |
| MLC Material | Tungsten Alloy | Tungsten Alloy | Same |
| Number of Leaves | 80 leaf pairs | 80 leaf pairs | Same |
| Range of MLC collimated beam size @ isocenter | 0.5 cm x 0.5 cm to 57.4 cm x 22 cm | 0.5 cm x 0.5 cm to 57.4 cm x 22 cm | Same |
| Gantry | Ring Gantry, collision with patient not possible | Ring Gantry, collision with patient not possible | Same |
| Radiation Head Shielding | Lead, Tungsten Alloy, and Steel shielding | Lead, Tungsten Alloy, and Steel shielding | Same |
| Source Control Mechanism | Dual channel dose monitoring system | Dual channel dose monitoring system | Same |
| Radiation Transmission through head | 0.2% of the primary beam | 0.2% of the primary beam | Same |
| Isocenter Distance | 143.5 cm | 143.5 cm | Same |
| Isocenter Accuracy (Radius) | 0.5mm | 0.5mm | Same |
| Max Dose Rate | Clinical use: 450 cG/min at isocentre at Dmax for a 10 cm x 10 cm field (500 MU/min @ isocentre measured at Dmax) | Clinical use: 450 cG/min at isocentre at Dmax for a 10 cm x 10 cm field (500 MU/min @ isocentre measured at Dmax) | Same |
| Static Dose Accuracy | >95% of points passing 3%/3mm in the high dose, low gradient region. >95% passing 5mm/5% for low dose, high gradient points. | >95% of points passing 3%/3mm in the high dose, low gradient region. >95% passing 5mm/5% for low dose, high gradient points. 1% agreement for output factors. | Same |
| Motion synchronized treatment | No - Manual interrupt only | No - Manual interrupt only | Same |
| Patient Table Degrees of Freedom | 2 (vertical & longitudinal) – positional corrections are made using the online adaptive planning interface of the treatment planning system | 2 (vertical & longitudinal) – positional corrections are made using the online adaptive planning interface of the treatment planning system | Same |
| Integrated Imaging for planning, positioning, gating | Magnetic resonance imaging system - for planning, positioning and motion monitoring during treatment | Magnetic resonance imaging system - for planning, positioning and motion monitoring during treatment | Same |
| MR Physical Characteristics | Not explicitly detailed for all, but overall performance metrics are compared. | Not explicitly detailed for all, but overall performance metrics are compared. | Primarily "Same" across various listed characteristics (Bore Diameter, MRI Frequency, Field Strength, Field of View, Field Homogeneity, Field Stability, 3D Imaging Volumes, 3D Imaging Resolution, 2D Imaging Planes, 2D Imaging Resolution, Geometric Accuracy, Signal to Noise). |
| Diffusion Weighted Imaging | Diffusion Weighted Images can be imported from an alternative magnetic resonance imaging device for Off-line review | Diffusion Weighted Images can be acquired on the Unity system for Off-line review. Single-shot EPI diffusion imaging (DWI) with 3 diffusion directions and up to 16 b-values. Diffusion imaging processing with automatic generation of the ADC and/or eADC maps. | SE image quality (indicates the new functionality meets equivalence standards) |
| Treatment Planning and Delivery System Dose Algorithm | GPU-based Monte Carlo dose calculation algorithm (GPUMCD) using the compatible Elekta MONACO treatment planning system | GPU-based Monte Carlo dose calculation algorithm (GPUMCD) using the compatible Elekta MONACO treatment planning system | Same |
| Dose Output Modelling | Dose output modelled with monitor units | Dose output modelled with monitor units | Same |
| Dose Display | Display of Linac delivery parameters | Display of Linac delivery parameters | Same |
| Minimum Room Dimensions (H/L/W) | 3.25 m x 6.7 m x 6.7 m | 3.25 m x 6.7 m x 6.7 m | Same |
| Environment Line Voltage | 480V | 480V | Same |
| Ambient Room Temp. | Treatment room: 18 to 22 °C (65 °F to 72 °F) | Treatment room: 18 to 22 °C (65 °F to 72 °F) | Same |
| Relative Humidity | Treatment room: 40 to 70%, non-condensing. | Treatment room: 40 to 70%, non-condensing. | Same |
| Power Distribution Isolation | Transformer | Transformer | Same |
| Image Quality (Diagnostic) | Clinical criteria for diagnostic MRI as determined by US Board Certified Diagnostic Radiologists. | Anonymized images, obtained on Elekta Unity, were reviewed by US Board Certificated Diagnostic Radiologists. Consensus among expert reviewers that imaging with Elekta Unity met the clinical criteria for diagnostic MRI. | Met. |
| General Safety and Performance | Conformance with design and risk management requirements, FDA guidance, and recognized consensus standards (IEC 60601-1, IEC 60601-2-1, IEC 60601-2-33, IEC 61217, IEC 60976, IEC 60601-1-2, IEC 62366-1, IEC 60601-1-6, ISO 10993-1). | Non-clinical testing evaluated device performance and functionality against design and risk management requirements. Software verification tested conforming to FDA's "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices, " May 2005 (Major level of concern). Basic safety and essential performance satisfied through conformance with listed standards. | Met. |
| Usability/Human Factors | Validation and usability testing under clinically representative conditions by competent and professionally qualified personnel. | Validation and usability testing of the integrated system performed in accordance on human factors and usability engineering under clinically representative conditions by competent and professionally qualified personnel. | Met. |
2. Sample Size Used for the Test Set and Data Provenance
- The document does not specify a numerical sample size for the "test set" used in the image validation study. It only mentions "anonymized images" from Elekta Unity.
- Data Provenance: The images were "obtained on Elekta Unity," implying they were internally generated or acquired from the device itself. Given the context of a 510(k) summary, it's highly likely these were retrospective images produced during internal testing or early clinical use for device characterization, rather than a prospective, formal diagnostic study with patient consent for external use. The country of origin is not specified, but the submission is from Elekta Limited in the UK.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- Number of Experts: More than one expert, specified as "US Board Certificated Diagnostic Radiologists." The exact number is not provided, but it implies a panel.
- Qualifications of Experts: "US Board Certificated Diagnostic Radiologists." No specific experience level (e.g., 10 years) is given.
4. Adjudication Method for the Test Set
- The adjudication method was consensus. The document states, "There was consensus among the expert reviewers that imaging with Elekta Unity met the clinical criteria for diagnostic MRI."
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
- No, an MRMC comparative effectiveness study was not explicitly stated or described. The study focused on the standalone performance and image quality of the Elekta Unity's MR imaging capabilities. It did not compare human readers with and without AI assistance; rather, it evaluated the diagnostic quality of the images generated by the device itself.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done
- Yes, a standalone performance evaluation of the imaging component was done. The image validation study assessed the quality of images produced by the Elekta Unity's MR scanner, interpreted by radiologists without any indication of AI assistance in the interpretation loop for the purpose of validating the device's inherent imaging capabilities. The main purpose of this 510(k) is the device itself (hardware and core software), not an AI diagnostic algorithm. The new features for diffusion imaging (DWI and ADC/eADC maps) are outputs of the device's imaging capabilities, which are then evaluated for their standalone image quality.
7. The Type of Ground Truth Used
- Expert Consensus. For the image validation, the ground truth was established by the "consensus among the expert reviewers that imaging with Elekta Unity met the clinical criteria for diagnostic MRI." For the device's overall safety and performance, the ground truth was established through conformance with recognized consensus standards and internal design and risk management requirements.
8. The Sample Size for the Training Set
- The document does not provide any information regarding a training set size. This submission is for the Elekta Unity hardware and its associated imaging capabilities, not primarily an AI/ML algorithm that would typically have a separate training set. The mention of "Diffusion imaging processing with automatic generation of the ADC and/or eADC maps" implies some algorithmic processing, but no details on training data for this specific processing are given.
9. How the Ground Truth for the Training Set Was Established
- As no training set is mentioned for the direct evaluation described, no information is provided on how its ground truth would have been established.
§ 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.