Search Results

PHAROS is a dedicated PET scanner intended to obtain Positron Emission Tomography (PET) images of parts of human body that fit in the patient aperture (brain, breast, arms and legs) to detect abnormal patterns of distribution of radioactivity after injection of a positron emitting radiopharmaceutical. This information can assist in diagnosis, therapeutic planning and therapeutic outcome assessment.

PHAROS is a specialized high-sensitivity and high-resolution PET system designed for imaging specific organs, such as the brain, breast, arms and legs.

Positron emission tomography (PET) captures images by detecting the distribution of internal radioactivity in human organs, utilizing radioactive pharmaceuticals. This technology reconstructs the body's internal biochemical and metabolic processes, producing high-resolution 3D visualizations. The method involves measuring a pair of simultaneous gamma rays, each with an energy of 511 keV, resulting from the annihilation of positrons. By labeling the positron emitter with a tracer and using a ring-shaped gamma ray detector, the spatial location of positron-emitting nuclides within the body is visualized.

PHAROS features four different scanning modes, each tailored for specific types of imaging:

1. Brain Scan Mode (Sitting Position):
   This mode is designed for brain imaging while the patient is seated.

2. Brain Scan Mode (Lying Position):
   This mode is designed for brain imaging while the patient lies down on a bed.

3. Breast Scan Mode:
   This mode is designed for breast imaging while the patient lies in a prone position.

4. Periphery Scan Mode:
   This mode is designed for imaging the periphery of the body, including the arms, hands, legs, and knees.

For both upper and lower extremity imaging, the height of detector head can be adjusted to ensure optimal patient comfort and accurate positioning. Aside from the physical height adjustment of the detector head, there is no difference in image acquisition method or image generation algorithm between upper and lower extremity scans.

Here's a summary of the acceptance criteria and study information for the PHAROS device, based on the provided FDA 510(k) clearance letter:

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample size used for the test set and data provenance

The document indicates that "a total of five images were obtained, including those from both patients and a normal control group" for the clinical evaluation.

The provenance of this data (e.g., country of origin, retrospective or prospective) is not explicitly stated in the provided text.

3. Number of experts used to establish the ground truth for the test set and their qualifications

Ground truth for the clinical acceptability of the five images was established by "a nuclear medicine physician". The exact number of physicians is not explicitly stated beyond "a physician," implying one. No specific years of experience or other qualifications are provided for this expert. It does not mention experts establishing a "ground truth" for the NEMA phantom performance tests, as these are objective measurements.

4. Adjudication method for the test set

The document states that the images were "assessed by a nuclear medicine physician for clinical acceptability." This implies a direct assessment by this physician. There is no mention of an adjudication method such as 2+1 or 3+1, suggesting a single expert's assessment without a formal adjudication process involving multiple readers for this specific clinical evaluation.

5. If a multi reader multi case (MRMC) comparative effectiveness study was done, and the effect size of how much human readers improve with AI vs without AI assistance

No, a multi-reader multi-case (MRMC) comparative effectiveness study evaluating human reader performance with and without AI assistance was not done or reported. The study appears to be a standalone performance evaluation of the device against objective phantom criteria and a limited clinical acceptability assessment.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done

The "Performance Testing – Bench" section, which evaluates the device against NEMA NU2:2018 and NEMA NU4:2008 standards (e.g., spatial resolution, scatter fraction, peak NECR, sensitivity, energy resolution, time resolution), represents a standalone evaluation of the device's intrinsic image acquisition and reconstruction capabilities. This can be considered a standalone performance assessment of the system. The clinical images were also reviewed by a physician, but the NEMA tests are purely objective, algorithm-only type performance.

7. The type of ground truth used

• For the bench tests (NEMA standards): The ground truth is established by the physical properties of the phantoms used in the NEMA NU2:2018 and NEMA NU4:2008 standards, and the adherence to these quantitative metrics. This is an objective, standardized ground truth.
• For the clinical evaluation: The ground truth for the five clinical images was based on the "clinical acceptability" determined by a nuclear medicine physician. This is a form of expert consensus/assessment, though it's not explicitly detailed how this "acceptability" was defined or if it referenced other diagnostic findings or pathology.

8. The sample size for the training set

The provided document does not mention a training set sample size. This 510(k) pertains to a PET scanner hardware device, not an AI/ML software device that typically requires a large training dataset for model development. While the device utilizes algorithms for image reconstruction, the focus here is on the system's physical performance and output quality rather than an AI model's training.

9. How the ground truth for the training set was established

As no training set is mentioned in the context of an AI/ML model for this device, this information is not applicable based on the provided text. The "ground truth" related to the device's fundamental function is based on established physics principles for PET imaging and standardized phantom measurements.

Ask a specific question about this device