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The Spectral CT 7000 family is a Computed Tomography X-Ray System intended to produce cross-sectional images of the body by computer reconstruction of x-ray transmission data taken at different angles and planes. This device may include signal analysis and display equipment, patient and equipment parts, and accessories.

The Spectral CT 7000 family system acquires one CT dataset - composed of data from a higher energy detected x-ray spectrum and a lower- energy detected x-ray spectra may be used to analyze the differences in the energy dependence of the attenuation coefficient of different materials. This allows for the generation of images at energies selected from the available spectrum and to provide information about the chemical composition of the body materials and/or contrast agents. Additionally, materials analysis provides for the quantification and graphical display of attenuation, material density, and effective atomic number.

This information may be used by a trained healthcare professional as a diagnostic tool for the visualization and analysis of anatomical and pathological structures in patients of all ages, and to be used for diagnostic imaging in radiology, interventional radiology, and cardiology as part of treatment preparation and radiation therapy planning. The Extended field of view images and respiratory correlated scanning (4DCT) are for treatment and radiation therapy planning/simulation usage only.

This device is indicated for head, whole body, cardiac and vascular X-ray Computed Tomography applications in patients of all ages.

The system is also intended to be used for low dose CT lung cancer screening for the early detection of lung nodules that may represent cancer*. The screening must be performed within the established inclusion criteria of protocols that have been approved and published by either a governmental body or professional medical society.

*Please refer to clinical literature, including the results of the National Lung Screening Trial (N Engl. J Med 2011; 365:395-409) and subsequent literature, for further information.

Spectral CT 7500 RT system is a whole-body computed tomography (CT) X-ray system featuring a continuously rotating X-ray tube and detectors gantry, and multi slice capability. The acquired X-ray transmission data is reconstructed by computer into cross-sectional images of the body taken at different angles and planes. This system also includes signals and display equipment, patient and equipment support, components, and accessories.

The Spectral CT 7500 RT system acquires one CT dataset – composed of data from a higher energy detected X-ray spectrum and a lower- energy detected X-ray spectra may be used to analyze the differences in the energy dependence of the attenuation coefficient of different materials. This allows for the generation of images at energies selected from the available spectrum and provides information about the chemical composition of the body materials and/or contrast agents. Additionally, materials analysis provides for the quantification and graphical display of attenuation, material density, and effective atomic number. The Spectral CT 7500 RT system consists of three main components – a scanner system that includes a rotating gantry, a movable patient couch, and an operator control and image reconstruction; a Spectral Reconstruction System; and a Spectral CT Viewer. On the gantry, the main active components are the X-ray high voltage (HV) power supply, the X-ray tube, and the detection system.

The provided documentation describes the acceptance criteria and the study that proves the Philips Medical Systems Technologies Ltd. Spectral CT 7500 RT device meets these criteria.

Here's the detailed breakdown:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implicitly derived from the successful verification and validation of the device against System Requirements Specifications (SRS) and User Requirement Specification (URS), as well as compliance with recognized standards. The reported device performance is presented as meeting these criteria for the key features considered in the 510(k) submission: Pulmonary Gating 4DCT and Extended Field of View (EFOV).

• Spectral Phantom Testing: No significant differences in Pulmo spectral results compared to non-Pulmo chest scans.
• Clinical External Image Quality Review: Overall image quality graded as satisfactory for use in CT simulation for radiotherapy planning, meeting defined success criteria. | - Motion Phantom Testing: "The review and the analysis showed that the level and magnitude of artifacts is similar to existing products under similar conditions and additionally that the differences seen are explainable based on design differences between the Spectral CT 7500 RT and the existing currently marketed and predicate device, Philips Big Bore system (K171850). Clinical evaluation determined the gated reconstruction is acceptable for RT simulation purposes."
• Spectral Phantom Testing: "Review of all of the spectral results did not reveal any significant differences between the Pulmo spectral results and the non-Pulmo chest scan that was used as a reference. This supports the conclusion that there are no significant differences in the Pulmo spectral results compared with the non-Pulmo spectral results."
• Clinical External Image Quality Review: "Clinical images were externally reviewed, by US board certified reviewers, grading their overall image quality for use in CT simulation for radiotherapy planning. The external IQ assessments of Pulmonary Gating 4DCT for both conventional 4DCT results and Spectral 4DCT results, were completed and the defined success criteria were met. All images were rated as satisfactory for radiation therapy planning/ simulation." |
  | Extended Field of View (EFOV) | - IQ Integration Tests: Meeting SRS IQ requirements for RT applications.
• Clinical External Image Quality Review: Overall image quality graded as satisfactory for use in CT simulation for radiotherapy planning, meeting defined success criteria. | - Overall Conclusion of the IQ Testing: "The review achieved its goal of reviewing the results of IQ integration tests for the extended FOV feature in the proposed Spectral CT 7500 RT system. The results showed that the IQ testing meets the SRS IQ requirements. These results are only intended to support RT applications."
• Conclusion of Clinical External Image Quality Review: "Clinical images were externally reviewed, by US board certified reviewers, grading their overall image quality for use in CT simulation for radiotherapy planning. The external IQ assessment of eFOV was completed and the defined success criteria were met. All images were rated as satisfactory for radiation therapy planning/ simulation." |
  | General System Performance | Compliance with recognized international and FDA consensus standards (listed in the document). Meets established system and sub-system level design input requirements. User needs and intended use are met. | The document states: "Non-clinical performance testing has been performed on the proposed Spectral CT 7500 RT system and demonstrates compliance with the following International and FDA recognized consensus standards and FDA guidance document(s)... System and sub-system verification activities demonstrate the system meet the established system and sub-system level design input requirements... All the validation tests as per validation plan were performed and acceptance criteria met for each of the requirements." |

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size for Test Set: The document does not explicitly state the numerical sample size (number of patients or scans) used for the "Clinical External Image Quality Review" for either Pulmonary Gating 4DCT or EFOV.
• Data Provenance: The document states that "Clinical images were externally reviewed." It also mentions "US board certified reviewers." While not explicitly stated, this suggests the clinical images are likely from a relevant patient population, and the review was conducted by US-based experts. The studies appear to be retrospective clinical evaluations of image quality rather than prospective patient studies, as there is no mention of patient enrollment, intervention, or clinical outcomes. The focus is on image quality review for simulation purposes.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

• Number of Experts: The document does not specify the exact number of experts used. It refers to "US board certified reviewers" in the plural, indicating more than one.
• Qualifications of Experts: The experts were "US board certified reviewers" who are involved in "CT simulation for radiotherapy planning." This implies they are likely board-certified radiologists or radiation oncologists with expertise in CT imaging for radiation therapy planning.

4. Adjudication Method for the Test Set

The document does not explicitly mention an adjudication method (e.g., 2+1, 3+1). It states "Clinical images were externally reviewed, by US board certified reviewers, grading their overall image quality..." This phrasing suggests that each reviewer likely provided their individual assessment against the success criteria, and the "defined success criteria were met," implying a consensus or a pass/fail threshold based on these independent gradings rather than a formal adjudication process to resolve disagreements.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No multi-reader multi-case (MRMC) comparative effectiveness study comparing human readers with AI assistance versus without AI assistance was done. The device is a CT imaging system with new features (Pulmonary Gating 4DCT and EFOV) primarily for radiation therapy planning, not an AI-assisted diagnostic tool for human readers. The evaluation focused on the image quality of the device output itself.

6. Standalone Performance Study (Algorithm Only Without Human-in-the-Loop)

Yes, a standalone performance study in terms of technical image quality was performed. For both Pulmonary Gating 4DCT and EFOV, there were:

• Motion Phantom Testing (for Pulmonary Gating 4DCT): Evaluated artifacts and reconstruction.
• Spectral Phantom Testing (for Pulmonary Gating 4DCT): Evaluated spectral results.
• IQ Integration Tests (for EFOV): Evaluated image quality against SRS requirements.

These phantom and integration tests assess the device's technical performance and image output without direct human interpretation in a clinical decision-making loop. The "Clinical External Image Quality Review" also assessed the images themselves, albeit by human experts, to confirm their suitability.

7. Type of Ground Truth Used

The ground truth for the test set was:

• Expert Consensus/Grading: For the "Clinical External Image Quality Review," the ground truth was established by "US board certified reviewers" who graded the overall image quality as "satisfactory for radiation therapy planning/simulation" against "defined success criteria."
• Phantom Measurements/Technical Specifications: For the phantom tests and IQ integration tests, the ground truth was based on pre-defined technical specifications and expected phantom characteristics (e.g., artifact levels, spectral properties, adherence to SRS IQ requirements).

8. Sample Size for the Training Set

The document does not mention a training set. This is because the Spectral CT 7500 RT is a hardware and software system for image acquisition and reconstruction, not a machine learning or AI model that typically requires a separate training set. The changes described are new software features and an extended field of view for an existing CT system.

9. How the Ground Truth for the Training Set Was Established

As no training set is mentioned or implied for this type of device, this question is not applicable. The device's performance demonstration relies on verification against design inputs, validation against user needs, and comparison to predicate devices, along with phantom and clinical image quality evaluations.

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