Limbus Contour is a software-only medical device intended for use by trained radiation oncologists, dosimetrists and physicists to derive optimal contours for input to radiation treatment planning. Supported image modalities are Computed Tomography and Magnetic Resonance. The Limbus Contour Software assists in the following scenarios: Operates in conjunction with radiation treatment planning systems to load, save, and display medical images and contours for treatment evaluation and treatment planning. Creation, transformation, and modification of contours for applications including, but not limited to: transferring contours to radiotherapy treatment planning systems, aiding adaptive therapy and archiving contours for patient follow-up. Localization and definition of healthy anatomical structures. Limbus Contour is not intended for use with digital mammography.

Device Description

Limbus Contour is a stand-alone software medical device. It is a single purposes cross-platform application for automatic contouring (segmentation) of CT/MRI DICOM images via pre-trained and expert curated machine learning models. The software is intended to be used by trained medical professionals to derive contours for input to radiation treatment planning. The Limbus Contour software segments normal tissues using machine learning models and further postprocessing on machine learning model prediction outputs. Limbus Contour does not display or store DICOM images and relies on existing radiotherapy treatment planning systems (TPS) and DICOM image viewers for display and modification of generated segmentations. Limbus Contour interfaces with the user's operating system file system (importing DICOM image .dcm files and exporting segmented DICOM RT-Structure Set .dcm files).

AI/ML Overview

The provided text describes the 510(k) submission for Limbus Contour, a software-only medical device for automatic contouring (segmentation) of CT/MRI DICOM images for radiation treatment planning. While the document outlines the device's indications for use, comparison to a predicate device, and general statements about software verification and validation, it does not provide specific acceptance criteria or detailed results of a study proving the device meets those criteria with numerical performance data.

The document states: "Validation testing of the following functions of the Limbus Contour application demonstrated that the software meets user needs and intended uses and to support substantial equivalence: Automatic Contouring Validation Test." However, it does not provide the specifics of this "Validation Test," such as pre-defined acceptance metrics (e.g., Dice Score thresholds, contour distance metrics), the performance achieved, or the methodology of the study.

Therefore, I cannot fulfill your request for:

A table of acceptance criteria and the reported device performance: This information is not present in the provided document.
Sample sized used for the test set and the data provenance: Not specified.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not specified beyond "expert curated machine learning models" in the device description.
Adjudication method: Not specified.
MRMC comparative effectiveness study: The document states "Clinical testing was not required to demonstrate the safety and effectiveness of Limbus Contour. Instead, substantial equivalence is based upon benchtop performance testing." This implies no MRMC study was performed.
Standalone (algorithm only) performance: While the device is "software-only," specific numerical performance metrics for its standalone contouring accuracy are not provided.
Type of ground truth used: Described as "pre-trained and expert curated machine learning models," but details on the ground truth for the specific validation test are missing.
Sample size for the training set: Not specified.
How the ground truth for the training set was established: Described as "pre-trained and expert curated machine learning models," but no specific methodology detail is given.

Conclusion based on the provided text:

The submission document only broadly states that "Validation testing" was performed and "demonstrated that the software meets user needs and intended uses." It lacks the detailed quantitative performance data and study methodologies typically found in a comprehensive clinical or performance study report. This kind of detail is usually provided in a separate report that would be referenced or included as an appendix in a full 510(k) submission, but it is not contained within this public summary letter.

Summary

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Image /page/0/Picture/0 description: The image contains the logos of the Department of Health & Human Services and the Food and Drug Administration (FDA). The Department of Health & Human Services logo is on the left, and the FDA logo is on the right. The FDA logo includes the letters "FDA" in a blue square, followed by the words "U.S. FOOD & DRUG ADMINISTRATION" in blue text.

April 7, 2023

Limbus AI Inc. % Mary Vater 510(k) Consultant Medical Device Academy 345 Lincoln Hill Rd SHREWSBURY VT 05738

Re: K230575

Trade/Device Name: Limbus Contour Regulation Number: 21 CFR 892.2050 Regulation Name: Medical Image Management And Processing System Regulatory Class: Class II Product Code: LLZ Dated: March 1, 2023 Received: March 29, 2023

Dear Mary Vater:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and 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 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) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's

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requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

Image /page/1/Picture/5 description: The image shows a digital signature. The signature is for Lora D. Weidner. The date of the signature is April 7, 2023. The time of the signature is 20:09:21 -04'00'.

Lora D. Weidner, Ph.D. Assistant Director Radiation Therapy Team DHT8C: Division of Radiological Imaging and Radiation Therapy Devices OHT8: Office of Radiological Health Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K230575

Device Name Limbus Contour

Indications for Use (Describe)

Limbus Contour is a software-only medical device intended for use by trained radiation oncologists, dosimetrists and physicists to derive optimal contours for input to radiation treatment planning

Supported image modalities are Computed Tomography and Magnetic Resonance. The Limbus Contour Software assists in the following scenarios:

· Operates in conjunction with radiation treatment planning systems to load, save, and display medical images and contours for treatment evaluation and treatment planning.

· Creation, transformation, and modification of contours for applications including, but not limited to: transferring
contours to radiotherapy treatment planning systems, aiding adaptive therapy and archiving contours for patient follow-up. · Localization and definition of healthy anatomical structures.
· Limbus Contour is not intended for use with digital mammography.

Type of Use (Select one or both, as applicable)
-------------------------------------------------

Prescription Use (Part 21 CFR 801 Subpart D)

| Over-The-Counter Use (21 CFR 801 Subpart C)

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510(k) SUMMARY

This summary of 510(k) safety and effectiveness information is submitted in accordance with the requirements of 21 CFR §807.92:

SUBMITTER -Limbus AI, Inc. 2076 Athol Street Regina, Saskatchewan, Canada, S4T3E5 Tel: 1-306-502-5982

Contact Person:	Mary Vater
Email:	mary@fdaecopy.com
Date Prepared:	February 28, 2023

II. DEVICE
Name of Device:	Limbus Contour
Classification Name:	Radiological Image Processing System
Regulation:	21 CFR §892.2050
Regulation Name:	Medical image management and processing system
Regulatory Class:	Class II
Product Classification Code:	LLZ

III. PREDICATE DEVICE Predicate Manufacturer:

Limbus Al, Inc. Predicate Trade Name: Limbus Contour Predicate 510(k): K201232

No reference devices were used in this submission.

IV. DEVICE DESCRIPTION

V. INDICATIONS FOR USE

Limbus Contour is a software-only medical device intended for use by trained radiation oncologists, dosimetrists and physicists to derive optimal contours for input to radiation treatment planning.

Supported image modalities are Computed Tomography and Magnetic Resonance. The Limbus Contour Software assists in the following scenarios:

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-Operates in coniunction with radiation treatment planning systems or DICOM viewing systems to load, save, and display medical images and contours for treatment evaluation and treatment planning.
-Creation, transformation, and modification of contours for applications including, but not limited to: transferring contours to radiotherapy treatment planning systems, aiding adaptive therapy and archiving contours for patient follow-up.
-Localization and definition of healthy anatomical structures.
-Limbus Contour is not intended for use with digital mammography.

VI. COMPARISON OF TECHNOLOGICAL CHARACTERISTICS WITH THE PREDICATE DEVICE

The following characteristics were compared between the subject device and the predicate device in order to demonstrate substantial equivalence:

Indications for Use The predicate and subject device are identical with the exception . that the predicate has support for MacOS while the subject device does not and the predicate has less structures for automatic contouring available.
. Materials – The predicate and subject device are software-only devices and do not inherently contain material.
Design - The predicate and subject device have equivalent designs.
. Energy Source – The predicate and subject device are software-only devices, powered by the computer system.
. Performance Testing - The predicate and subject device were both were validated using an automatic contouring test to ensure the contours were accurate.

	Limbus Contour v1.7	Limbus Contour v1.1 -K201232	Similarities /Differences
ClassificationRegulation	892.2050 – PictureArchiving andCommunication System	892.2050 – PictureArchiving andCommunication System	Same
Product Code	LLZ	LLZ	Same
Indications for Use
Limbus Contour is asoftware only medicaldevice intended for useby trained radiationoncologists, dosimetristsand physicists to deriveoptimal contours forinput to radiationtreatment planning.Supported imagemodalities are ComputedTomography andMagnetic Resonance.The Limbus ContourSoftware assists in thefollowingscenarios:• Operates in conjunctionwith radiation treatmentplanning systems orDICOM viewing systemsto load, save, anddisplay medical imagesand contours fortreatmentevaluation and treatmentplanning.• Creation, transformation,and modification ofcontours for applicationsincluding, but not limitedto: transferringcontours to radiotherapytreatment planningsystems, aidingadaptive therapy andarchiving contours forpatient follow-up.• Localization anddefinition of healthyanatomicalstructures.	Limbus Contour is asoftware only medicaldevice intended for useby trained radiationoncologists, dosimetristsand physicists to deriveoptimal contours forinput to radiationtreatment planning.Supported imagemodalities are ComputedTomography andMagnetic Resonance.The Limbus ContourSoftware assists in thefollowingscenarios:• Operates in conjunctionwith radiation treatmentplanning systems orDICOM viewing systemsto load, save, anddisplay medical imagesand contours fortreatmentevaluation and treatmentplanning.• Creation, transformation,and modification ofcontours for applicationsincluding, but not limitedto: transferringcontours to radiotherapytreatment planningsystems, aidingadaptive therapy andarchiving contours forpatient follow-up.• Localization anddefinition of healthyanatomicalstructures.	Same
	Limbus Contour is notintended for use withdigitalmammography.	Limbus Contour is notintended for use withdigital mammography.	Same
Intended User	Healthcare providers	Healthcare providers	Same
ContouringModes	Automatic	Automatic	Same
Measurements	No measurementfunction.	No measurementfunction.	Same.
Image Fusion	No fusion support.	No fusion support.	Same
3D imagerendering	No image renderingfunction.	No image renderingfunction.	Same
ImageModalities	CT and MR	CT and MR	Same
Platform	Stand-alone packagewhich operates onMicrosoftWindows operatingsystem operatingsystem	Stand-alone packagewhich operates onMicrosoftWindows operatingsystem and MacOSoperating system	LimbusContour v1.7does notsupportMacOSoperatingsystem
Environmentof Use	Healthcare environment	Healthcare environment	Same
Materials	N/A – StandaloneSoftware	N/A - StandaloneSoftware	Same
Energy Source	N/A - StandaloneSoftware	N/A - StandaloneSoftware	Same
FeatureComparison:• OperatingSystem• HardwareRequirements• Etc.	Operating System• Windows 10 /Windows Server2016 and AboveHardware Requirements• 2 GHz or faster multi-core processor• 8 GB of RAM• For GPU versions, aCUDA capableNVIDIA GPU isrequired	Operating System• Windows 10 /Windows Server2016• Mac OS 10.14Hardware Requirements• 2 GHz or faster multi-core processor• 4 GB of RAM• For GPU versions, aCUDA capableNVIDIA GPU isrequired	LimbusContour v1.7does notsupportMacOSoperatingsystem.RAMrequirementsare increasedto 8GB inLimbusContour v1.7
PerformanceTesting	Two different types ofverification testingwereconducted to verify thesoftware requirements:Manual and Automated.All tests passed,demonstrating that thesoftware performanceis in accordance withthe stated softwarerequirements.Validation testing ofthefollowing functions of theLimbus Contourapplicationdemonstrated that the	Two different types ofverification testing wereconducted to verify thesoftware requirements:Manual and Automated.All tests passed,demonstrating that thesoftware performance isin accordance with thestated softwarerequirements.Validation testing of thefollowing functions of theLimbus Contourapplication demonstratedthat the software meetsuser needs and intendeduses and to support	Same
	software meets userneeds and intendeduses and to supportsubstantial equivalence:• AutomaticContouring -Validation-Test	substantial equivalence:• AutomaticContouring -Validation-Test
Structuresavailable forautomaticcontouring	A_AortaA_Aorta_IA_CeliacA_LADA_Mesenteric_SA_PulmonaryBag_BowelBag_Bowel_ExtendBag_Bowel_FullBag_Bowel_SBladderBladderBodyBone_HyoidBone_IliumBone_Ilium_LBone_Ilium_RBone_MandibleBowelBowel_ExtendBowel_FullBowel_SBrachialPlex_LBrachialPlex_RBrachialPlexsBrainBrainstemBrainstemBreast_LBreast_RBreastsBronchusCanal_AnalCaudaEquinaCavity_OralChestwallChestwall_LChestwall_RClavicle_LClavicle_RCochlea_LCochlea_R	A_AortaBladderBrainBrainStemLN_Neck_LLN_Neck_REsophagusFemur_Head_LFemur_Head_RGlobe_LGlobe_RHeartGlnd_Lacrimal_LGlnd_Lacrimal_RLens_LLens_RLung_LLung_RMandibleOpticNrv_LOpticNrv_RParotid_LParotid_RProstateRectumGlnd_Submand_LGlnd_Submand_RSpinalCordTrachea	LimbusContourv1.7.0contains newstructures forautomaticcontouring
Colon_Sigmoid
Cornea_L
Cornea_L
Cornea_R
Cornea_R
Cricoid
Duodenum
Esophagus
Eye_L
Eye_L
Eye_R
Eye_R
Eyes
Femur_Head_L
Femur_Head_R
Femur_Heads
Gallbladder
Glnd_Lacrimal_L
Glnd_Lacrimal_R
Glnd_Submand_L
Glnd_Submand_R
Glnd_Thyroid
GreatVes
Heart
Hippocampus_L
Hippocampus_L
Hippocampus_R
Hippocampus_R
Humerus_L
Humerus_R
Kidney_L
Kidney_R
Kidneys
Larynx
Lens_L
Lens_R
Lips	Lip
Liver
LN_Ax_L1_L
LN_Ax_L1_R
LN_Ax_L2_L
LN_Ax_L2_R
LN_Ax_L3_L
LN_Ax_L3_R
LN_Ax_Sclav_L
LN_Ax_Sclav_R
LN_IMN_L
LN_IMN_R
LN_Neck_234_L
LN_Neck_234_R
LN_Neck_2347AB_L

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Limbus Al Limbus Contour 510(k) Submission

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LN_Neck_2347AB_R
LN_Neck_IA
LN_Neck_IA6
LN_Neck_IB_L
LN_Neck_IB_R
LN_Neck_II_L
LN_Neck_II_R
LN_Neck_III_L
LN_Neck_III_R
LN_Neck_IV_L
LN_Neck_IV_R
LN_Neck_L
LN_Neck_R
LN_Neck_V_L
LN_Neck_V_R
LN_Neck_VI
LN_Neck_VIIAB_L
LN_Neck_VIIAB_R
LN_Pelvics
LN_Sclav_L
LN_Sclav_R
Lung_L
Lung_R
Lungs
Musc_Constrict
Musc_PecMinor_L
Musc_PecMinor_R
Musc_Sclmast_L
Musc_Sclmast_R
OpticChiasm
OpticNrv_L
OpticNrv_R
Optics
Pancreas
Parotid_L
Parotid_R
PelvisVessels
PenileBulb
PenileBulb
Pituitary
Prostate
Prostate
Prostate + SeminalVes
PubicSymphys
Rectum
Rectum
Retina_L
Retina_L
Retina_R
Retina_R
Ribs
Ribs_L
Ribs_R
Sacrum
SeminalVes
SeminalVes
Skin
SpinalCanal
SpinalCord
Spleen
Sternum
Stomach
Trachea
Uterus_Cervix
V_Venacava_I
V_Venacava_S
Vagina
Ventricle_L

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VII. PERFORMANCE DATA

The following performance data were provided in support of the substantial equivalence determination.

Sterilization & Shelf-life Testing

The subject device is a software-only device. Therefore sterilization and shelf-life are not applicable.

Biocompatibility

The subject device is a software-only device. There are no direct patient-contacting components of the subject device. Therefore, patient contact information is not needed for this device

Electrical safety and electromagnetic compatibility (EMC)

The subject device is a software-only device. It contains no electric components, generates no electrical emissions, and uses no electrical energy of any type; therefore, this section is not applicable.

Software Verification and Validation Testing

Software verification and validation testing were conducted as recommended by FDA's Guidance for Industry and FDA Staff, "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices." The software for this device was considered as a moderate level of concern.

Two different types of verification testing were conducted to verify the software requirements: Manual and Automated. All tests passed, demonstrating that the software performance is in accordance with the stated software requirements.

Validation testing of the following functions of the Limbus Contour application demonstrated that the software meets user needs and intended uses and to support substantial equivalence:

· Automatic Contouring Validation Test

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Mechanical and Acoustic Testing

Not Applicable (Standalone Software)

Animal Study

Animal performance testing was not required to demonstrate safety and effectiveness of the device.

Clinical Studies

Clinical testing was not required to demonstrate the safety and effectiveness of Limbus Contour. Instead, substantial equivalence is based upon benchtop performance testing.

VIII. CONCLUSIONS

The minor differences in indications of use between the subject Limbus Contour software and the predicate Limbus Contour software do not constitute a different intended use. The technological characteristics of the Limbus Contour software are similar to those of the predicate Limbus Contour software. Results of software verification testing demonstrate that the Limbus Contour software performs in accordance with specifications and that the performance is comparable to that of the predicate device. Therefore, the Limbus Contour software can be found to be substantially equivalent to the predicate Limbus Contour software device.

Regulation Number and Section

§ 892.2050 Medical image management and processing system.

(a)
Identification. A medical image management and processing system is a device that provides one or more capabilities relating to the review and digital processing of medical images for the purposes of interpretation by a trained practitioner of disease detection, diagnosis, or patient management. The software components may provide advanced or complex image processing functions for image manipulation, enhancement, or quantification that are intended for use in the interpretation and analysis of medical images. Advanced image manipulation functions may include image segmentation, multimodality image registration, or 3D visualization. Complex quantitative functions may include semi-automated measurements or time-series measurements.(b)
Classification. Class II (special controls; voluntary standards—Digital Imaging and Communications in Medicine (DICOM) Std., Joint Photographic Experts Group (JPEG) Std., Society of Motion Picture and Television Engineers (SMPTE) Test Pattern).