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.

AI/ML Overview

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.

Summary

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JUL 27 1998

510(k) Summary

K980526

for Photoelectron Corporation PRS400 PHOTON RADIOSURGERY SYSTEM

Date Prepared: February 9, 1998 1.
Submitter's Name and Address: 2.

Photoelectron Corporation 5 Forbes Road Lexington, MA 02173

Contact Person: 3.
Thomas R. Varricchione, MBA, RRT Director, Clinical Research and Regulatory Affairs Photoelectron Corporation

Telephone: (781) 861-2069 (781) 259-0482 Facsimile:

Device Name: 4.

Proprietary Name:	Photon Radiosurgery System (PRS)
Common Name:	Miniature X-Ray Source with Control and CalibrationSystems and Accessories
Classification Name:	X-ray Radiation Therapy System

Predicate Device: 5.

The PRS400 Photon Radiosurgery System (PRS) is substantially equivalent to the PRS Model 3. A 510(k) for the PRS Model 3 was cleared by FDA on June 20, 1997 (K964947).

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Device Description: 6.

The key differences between the PRS400 and the PRS Model 3 are summarized below:

The X-ray Source (XRS) is slightly larger and heavier. The circuit architecture . and layout have been redesigned to permit additional functions to be built into the XRS enclosure. The probe and the output of the PRS400 XRS are essentially the same as the Model 3.
The PRS400 Control Console has been redesigned to include an on-board . microprocessor. The external lap-top computer used with the Model 3 has been eliminated. Control of the system is now menu-driven through commands entered from a front panel keypad.
. The Probe sheath used to provide a biocompatible, sterile barrier between the patient and the probe will be packaged sterile for the PRS400 instead of needing to be sterilized by the user.

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7. Intended Use:

The intended use of the Photon Radiosurgery System is to irradiate intracranial tumors.

Comparison of Technological Characteristics: 8.

The technological and functional characteristics of the PRS400 are essentially identical to the PRS Model 3. The changes to the PRS components incorporated in the PRS400 are refinements to their design and do not represent technological changes. The radiation source used in both models is essentially the same and produces nearly identical radiative output.

Nonclinical Tests: 9.

Non-clinical testing conducted on the PRS included the following:

Electromagnetic Compatibility: The PRS complies with the requirements of EN 60601-1-2

In Vitro Laboratory Studies: In vitro laboratory studies were performed to compare the radiative properties of the Model 3 and the PRS400. These studies demonstrate that the PRS400 and the Model 3 produce the same output which is characterized by a low photon energy and a steep fall-off in dose with distance from the probe. The dose distribution around the probe is nearly spherical.

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Image /page/3/Picture/0 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized depiction of an eagle or bird-like figure with three curved lines representing its body and wings. The logo is encircled by the text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" in a circular arrangement.

DEPARTMENT OF HEALTH & HUMAN SERVICES

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

Thomas R. Varricchione, MBA, RRT Director, Clinical Research and Regulatory Affairs PeC Photoelectron Corporation 5 Forbes Road Lexington, MA 02173

Re:

K980526 Photon Radiosurgery System PRS400 Dated: May 20, 1998 Received: May 21, 1998 Regulatory class: II 21 CFR 892.5900/Procode: 90 JAD

Dear Mr. Varricchione:

JUL 2 7 1998

We have reviewed your Section 510/k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.

If your device is classified (see above) into either class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4613. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address "http://www.fda.gov/cdrh/dsmaddsmamain.html".

Sincerely yours,

Kilian Yi

Lillian Yin, Ph.D Director, Division of Reproductive Abdominal, Ear, Nose and Throa and Radiological Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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980526 510(k) Number (if known): _

Photon Radiosurgery System (PRS) PRS400 Device Name: __

Indications For Use:

. .

The Photon Radiosurgery System is intended to be used for the irradiation on intracranial tumors.

(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NECESSARY)

Concurrence of CDRH, Office of Device Evaluation (ODE) (Division Sign-Off) Division of Reproductive, Abdominal, ENT, and Radiological Deyi 510(k) Number Over-The-Counter Use __ OR Prescription Use _ 1 (Per 21 CFR 801.109)

Regulation Number and Section

§ 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.