(167 days)
The Photon Radiosurgery System is intended to be used for the irradiation on intracranial tumors.
The PRS400 Photon Radiosurgery System is a modification of the Photoelectron Corporation PRS Model 3. Modifications have been made to increase radiation safety, improve the user interface with the system, and improve manufacturability of the PRS components. None of the changes affect the function, intended use, or overall design of the PRS. Both devices are complete systems for highly focused treatment of intracranial tumors. The heart of the system is a miniature, high dose rate, low energy X-ray source equipped with a 3.175 mm diameter, 10 cm long interstitial probe. The X-ray source is designed so that the tip of the probe can be positioned precisely into the tumor and a prescribed therapeutic radiation dose delivered in a single fraction. X-rays are emitted from the tip of the PRS' probe in a spherically symmetric pattern and the tumor is destroyed from the inside out. A sterile sheath is placed over the probe prior to insertion into the turnor. The voltage, current, and exposure time of the X-rays are set via the PRS400 Control Console. A complete set of accessories is provided to assist in placement of the interstitial probe and to perform quality control of the X-ray source in the clinical setting. Additional laboratory-based components of the PRS include an automated dosimetry water tank for calibration and a CCD-camera based radio chromic film reader for dose verification.
The provided document is a 510(k) summary for the Photoelectron Corporation PRS400 PHOTON RADIOSURGERY SYSTEM. This submission is for a medical device that delivers radiation therapy, not an AI/ML powered device. As such, the standard acceptance criteria for AI/ML devices (e.g., sensitivity, specificity, AUC) and associated study methodologies (e.g., MRMC, standalone performance) are not applicable.
The document describes non-clinical tests performed to demonstrate substantial equivalence to a predicate device, the PRS Model 3.
Here's an analysis based on the document's content:
1. Table of Acceptance Criteria and Reported Device Performance:
Since this is not an AI/ML device, the acceptance criteria are based on demonstrating comparable performance and safety to a predicate device, specifically regarding its radiative properties.
| Acceptance Criteria Category | Specific Criteria/Tests | Reported Device Performance (PRS400 vs. PRS Model 3) |
|---|---|---|
| Electromagnetic Compatibility | Compliance with EN 60601-1-2 | The PRS complies with the requirements of EN 60601-1-2. |
| Radiative Properties Equivalence | Production of "same output" in terms of: |
- Low photon energy
- Steep fall-off in dose with distance from the probe
- Nearly spherical dose distribution around the probe | In vitro laboratory studies demonstrate that the PRS400 and the Model 3 produce the "same output" characterized by:
- Low photon energy
- Steep fall-off in dose with distance from the probe
- Nearly spherical dose distribution around the probe. |
| Function, Intended Use, Overall Design Equivalence | No changes affecting these aspects compared to the predicate device. | "None of the changes affect the function, intended use, or overall design of the PRS."
"The technological and functional characteristics of the PRS400 are essentially identical to the PRS Model 3." |
| Radiation Source Equivalence | Radiation source in PRS400 is "essentially the same" as PRS Model 3 and produces "nearly identical radiative output." | "The radiation source used in both models is essentially the same and produces nearly identical radiative output." |
2. Sample size used for the test set and the data provenance:
- Sample Size: The document does not specify a "sample size" in the context of a statistical study with a defined test set. The non-clinical tests described are "In vitro Laboratory Studies" comparing the radiative properties of the two devices. It implies multiple measurements were taken to characterize the output, but the exact number of instances or measurements is not provided.
- Data Provenance: The studies were "In vitro Laboratory Studies." The country of origin is implicitly the United States, given the submitter's address and the FDA submission. The studies are prospective in the sense that they were conducted specifically for this submission to characterize the new device.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This question is not applicable to this type of device submission. Ground truth, in the context of AI/ML, refers to a definitively correct answer established by human experts or other objective means. For a radiation delivery device, the "ground truth" is measured physical properties like dose distribution, photon energy, and fall-off rates, which are determined by physical dosimetry and equipment, not human expert consensus.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- Not applicable. Adjudication methods are typically used to resolve discrepancies in expert-assigned ground truth in subjective assessments for AI/ML models. The PRS400's performance is objectively measured.
5. 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 applicable. The PRS400 is a radiation delivery system, not an AI-assisted diagnostic or treatment planning tool. There are no "human readers" in the context of interpreting the device's output to make a diagnosis or directly interact with the device's primary function in this manner.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Not applicable. The PRS400 is hardware with embedded control systems, not a standalone AI algorithm. Its performance is inherent in its physical and electrical design. The "In vitro Laboratory Studies" essentially measure the standalone physical performance of the device without patient interaction, but this is a characterization study, not an algorithm performance study.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The "ground truth" for the non-clinical tests was the physical measurement and characterization of the radiation output of the PRS400, compared against the known and accepted physical properties of the predicate PRS Model 3. This involved dosimetry (measuring dose distribution) and characterization of photon energy.
8. The sample size for the training set:
- Not applicable. This is not an AI/ML device that requires a training set.
9. How the ground truth for the training set was established:
- Not applicable. This is not an AI/ML device that requires a training set.
§ 892.5900 X-ray radiation therapy system.
(a)
Identification. An x-ray radiation therapy system is a device intended to produce and control x-rays used for 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.