MLC FIT by IMPAC MEDICAL SYSTEMS, INC.

MLC Fit is to be used to define leaf plans for use with radiation treatment machines equipped with multileaf collimators manufactured by Siemens Medical Systems, Varian Associates, and With manned conniness Inc. This method of defining the geometric parameters associated with treatment fields can be used whenever a conformal treatment field is desired.

Device Description

The primary function of MLC Fit is to provide a means to define multileaf collimator leaf plans based on a user defined shape of a desired treatment area for use with a cancer radiotherapy treatment machines equipped with multileaf collimators manufactured by Siemens Medical Systems, Varian Associates, or Elekta Oncology Systems, Inc. Users may create, view, and edit MLC leaf data as well as other geometric parameters associated with treatment field definitions.

AI/ML Overview

The provided document MLC Fit - 510(k) - Response to Request for Additional Information is a 510(k) submission from 1999 and therefore does not contain the structured information typically found in modern AI/ML device submissions regarding acceptance criteria and performance studies. The document describes a software called MLC Fit designed to define multileaf collimator leaf plans for cancer radiotherapy. It emphasizes the software's function in eliminating manual calculation errors and its compliance with quality systems but does not detail specific performance metrics, clinical studies, or acceptance criteria in the manner requested.

However, based on the text, we can infer some aspects and highlight what is missing relative to modern AI/ML device descriptions.

Inferred Information and Missing Details:

A table of acceptance criteria and the reported device performance:
- Inferred Acceptance Criteria: The primary goal of MLC Fit is to "provide the leaf positions for a given treatment shape in a manner that eliminates the slow and error prone method of hand calculating the position for each leaf." This suggests implicit acceptance criteria related to accuracy and efficiency compared to manual methods.
- Reported Device Performance: The document states, "The primary functions of MLC Fit are, in effect, the same as those of MLC Fit product (K962335) currently being marketed by IMPAC Medical Systems, Inc." This implies equivalence to a previously cleared device, which served as its predicate. However, no specific quantitative performance metrics (e.g., accuracy, precision, speed improvements) are provided in this document. There is no table presenting performance data against defined thresholds.
Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective):
- Not provided. The document does not mention any specific test sets, sample sizes, or data provenance from clinical sources.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience):
- Not applicable/Not provided. Since no specific test set or ground truth establishment based on expert consensus for clinical accuracy is described, this information is not present. The software's function is geometrical definition, not diagnostic interpretation.
Adjudication method (e.g. 2+1, 3+1, none) for the test set:
- Not applicable/Not provided. There is no mention of an adjudication process for a clinical test set.
If a multi-reader multicase (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:
- No, not done/applicable. This device is not an AI/ML diagnostic or assistive tool for human readers in the traditional sense of interpreting images. It is a tool for defining treatment field geometry. The effect size of how human planners improve in efficiency and accuracy with MLC Fit vs. manual methods is implied as beneficial ("eliminates the slow and error prone method"), but no quantitative study or effect size is provided.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- The MLC Fit is a standalone algorithm in its core function: "It only provides the definition of the treatment field as a hardcopy and to a database file." However, this is not an "AI algorithm" in the modern sense. Its performance relates to its ability to generate correct geometric parameters based on user input, not to make independent clinical decisions or interpretations. The users can "adjust" parameters, indicating it's a human-in-the-loop tool whose output can be modified. No formal standalone performance study report is provided.
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- Not applicable/Not explicitly stated for a clinical context. For a geometry definition tool, the "ground truth" would likely be the mathematically correct or clinically desired geometric configuration for a given treatment plan. This would be established by physics principles and clinical requirements, rather than pathology or outcomes data. The document mentions "Software Requirements Specifications and documented by Software Design Descriptions" which would define the expected behavior and correctness (the 'truth') of the geometric calculations.
The sample size for the training set:
- Not applicable/Not provided. This device, as described in 1999, does not appear to be an AI/ML device that uses a "training set" in the contemporary sense. It is a rule-based or algorithmic software tool implementing geometric calculations.
How the ground truth for the training set was established:
- Not applicable/Not provided. As there's no mention of a training set, the establishment of its ground truth is also not applicable or discussed.

Summary of Missing Information (Common in Modern AI/ML Submissions):

Quantitative performance metrics (e.g., sensitivity, specificity, accuracy, precision, AUC)
Specific acceptance criteria with numerical thresholds
Details of a validation dataset (size, characteristics, provenance)
Methodology for establishing clinical ground truth (e.g., expert panel, histopathology, long-term outcomes)
Results of comparative studies (e.g., non-inferiority trials, MRMC studies)
Specific information about AI/ML model training (training set size, annotation methods, type of model)

This 510(k) submission from 1999 primarily focuses on describing the device's function, its equivalence to a predicate device, and the adherence to quality systems in its development. It predates the widespread regulatory requirements for detailed performance evaluation of AI/ML-driven medical devices.

Summary

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MLC Fit - 510(k) - Response to Request for Additional Information

8/25/99

1991133

MAR 2 7 2000

MLC Fit Non-Confidential Summary of Safety and Effectiveness

The goal of MLC Fit is to provide the leaf positions for a given treatment shape in a manner that eliminates the slow and error prone method of hand calculating the position for each leaf and manually setting up the leaf plans. MLC Fit allows the users to define treatment field shapes and generate multileaf collimator leaf plans based on that input shape. Leaf positions and other geometric parameters can be adjusted to meet the user's clinical requirements. MLC Fit is not capable of moving the leaves or other parameters to the calculated positions. It only provides the definition of the treatment field as a hardcopy and to a database file.

The primary functions of MLC Fit are, in effect, the same as those of MLC Fit product (K962335) currently being marketed by IMPAC Medical Systems, Inc. (see Exhibit 3b). Both systems supplement the MLC treatment field definition process only, and do not attempt to control the movement of the defined parameters. The main difference is that the updated MLC Fit product has been expanded to support Elekta multileaf collimators. The user describes the characteristics of the collimator and MLC Fit uses this characterization to create the treatment definition.

IMPAC Medical Systems, Inc., has gained a reputation of providing high quality software products which serve the cancer therapy community. One reason we have earned this reputation is that we strive to provide end-user process oriented solutions with our products. Another reason is that software development for cancer therapy is our only business. This allows us to invoke a development system designed specifically for a cancer therapy software business. Strict adherence to these processes will ensure that MLC Fit is a safe and effective product suitable for use as intended in a cancer therapy department.

MLC Fit was designed and developed under the IMPAC Quality System. The IMPAC Quality System governs the processes by which system and software development are to be defined, implemented, tested, released, installed, and supported. In addition, the IMPAC Quality System demonstrates how IMPAC Medical Systems, Inc., conforms to the Quality System Regulations, 21 CFR 820, and other applicable regulations.

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Under the processes set forth in the IMPAC Quality System, MLC Fit was developed per Software Requirements Specifications and documented by Software Design Descriptions. Samples of these are shown in Exhibits 4 and 5 for your review.

In addition, a Hazard Analysis was performed to determine and evaluate the areas which represent potentials hazards during MLC Fit operation. For hazards within the scope of the MLC Fit product, the hazard, effect, and protection implemented were documented and reviewed. The System Hazard Analysis is included in Exhibit 6.

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Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

MAR 27 2000

Thomas Faris Regulatory Affairs Manager IMPAC Medical Systems, Inc. 215 Castro Street Mountain View, CA 94041

Re:

K991133 MLC Fit (Multi Leaf Collimator Planning Software) Dated: January 18, 2000 Received: January 19, 2000 Regulatory class: II 21 CFR 892.5050/Procode: 90 IYE

Dear Mr. Faris:

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 legally marketed predicate devices marketed in interstate commerce pror 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 Aproval), 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 requlation 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 531 through 542 of the Act for devices under 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) 594-4591. 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" (21CFR 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/dsmaldsmamain.html".

Sincerely yours,

Daniel C. Schultz, M.D.

Daniel G. Schultz, M.D. Captain, USPHS Director, Division of Reproductive, Abdominal, and Radiological Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure(s)

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MLC Fit Indications for Use Statement

David A. Leymm
(Division Sign-Off)

Division of Reproductive, Abdominal, ENT, and Radiological Devices 510(k) Number

Prescription Use
(Per 21 CFR 801.109)

Regulation Number and Section

§ 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.