Search Results

This is to certify that the BodyLoc™™ Whole Body Stereotactic Localizer System For Radiotherapy, as submitted under the above referenced 510(k) number, is indicated for use as a precision patient immobilization and positioning system for the purpose of performing diagnostic localization and fractionated stereotactic radiotherapy/ radiosurgery treatment. It is substantially equivalent to similar devices which are used to position the body during stereotactic radiotherapy of various body lesions. The decision and conditions under which the system is to be used is made by the patient's managing physician(s).

The BodyLoc" is a body stereotactic localizer system which utilizes a coordinate reference system that can be used to reproducibly localize targets during diagnostic and treatment procedures. Stereotactic localization fiducials are positioned in the sides and base of the BodyLoc™ and the localization system is continuous from the head to mid-thigh regions. The BodyLoc" is supplied with a software program for calculation of BodyLoc" stereotactic coordinates from scanner images. Software is functional on IBM or IBM-compatible PC computers with Microsoft® Windows 95. Targets within the system can be aligned by use of the coordinate indicators on the sides of the frame and the moveable arc localizer. Immobilization is achieved by the use of a vacuum mold system or polyurethane foam mold for posterior (the part of the body nearest the frame base) areas and a thermoplastic body mold to cover large body surfaces in the ventral or anterior plane. The BodyLoc™ has quality assurance markers in its base which are used to aid in system set-up and in verifying the accuracy of the coordinate alignment and target calculations.

The provided text describes the "BodyLoc™ Whole Body Stereotactic Localizer System For Radiotherapy" and presents a comparison to predicate devices, including performance data. However, it does not describe acceptance criteria in the traditional sense of pre-defined thresholds that the device must meet, nor does it detail a clinical study with a specified test set and ground truth. Instead, it demonstrates "substantial equivalence" to legally marketed predicate devices through a comparison of technological characteristics and performance metrics.

Here's an attempt to structure the information based on your request, highlighting what is implicitly or explicitly stated and what is missing:

1. Table of Acceptance Criteria and Reported Device Performance

The document doesn't explicitly state "acceptance criteria" but rather presents a comparison table where the performance of the BodyLoc™ is compared to predicate devices. The implicit acceptance criterion is that the BodyLoc™'s performance should be "substantially equivalent" or better than the predicate devices.

Note: The document describes "an overall accuracy range substantially equivalent to that of predicate devices," which is a general statement. The specific numbers provided in the table indicate that the BodyLoc™ actually exceeds the performance of the predicate devices in terms of localization error, rather than just being "equivalent."

2. Sample Size Used for the Test Set and Data Provenance

• Test Set Sample Size: The document mentions "test calculations and measurements of multiple targets throughout the BodyLoc™ using various axial scan slice thicknesses." However, it does not specify a numerical sample size for the test set (e.g., number of targets, number of scan slices, or number of tests).
• Data Provenance: The tests were "developed and performed by MIDCO®" for its BodyLoc System. The context suggests these were retrospective/benchtop tests conducted by the manufacturer, not clinical trials with human subjects. The country of origin of the data is not explicitly stated beyond MIDCO® being a US company.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

The document does not mention the involvement of any experts (e.g., radiologists) in establishing ground truth for the performance tests. The ground truth for the localization and setup error measurements was likely established through precise physical measurements and pre-defined coordinates within the device itself:

• "Stereotactic localization fiducials are positioned in the sides and base of the BodyLoc™ and the localization system is continuous from the head to mid-thigh regions."
• "The BodyLoc™ has quality assurance markers in its base which are used to aid in system set-up and in verifying the accuracy of the coordinate alignment and target calculations."

This suggests the ground truth was based on the known physical locations of these fiducials and markers.

4. Adjudication Method for the Test Set

No adjudication method is described. The tests were likely objective measurements against known physical standards.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No MRMC comparative effectiveness study was conducted or reported. The device is a physical immobilization and localization system, not an AI or imaging diagnostic tool that would typically involve human readers interpreting output.

6. Standalone Performance Study

Yes, a standalone performance study was conducted. The reported performance metrics (CT localization error, LINAC Set-up Error) are "algorithm only" or "device only" metrics, demonstrating the accuracy of the BodyLoc™ system and its associated software for calculating stereotactic coordinates. The studies evaluated:

• "the accuracy of the fiducial system."
• "the axial imaging localization algorithm used with the fiducial system."
• "the fiducial localization system in relation to quality assurance reference markers embedded in the base of the localizer at known stereotactic frame z-axis levels."
• "The imaging fiducial localization algorithm was then tested against a scanner screen measurement method."

7. Type of Ground Truth Used

The ground truth used was based on known physical coordinates of fiducials and quality assurance markers embedded within the BodyLoc™ frame. This is effectively a physical standard or engineered ground truth, rather than expert consensus, pathology, or outcomes data, which are typically used for diagnostic or predictive AI.

8. Sample Size for the Training Set

No training set is mentioned. This device is a physical system with an associated software for coordinate calculation, not a machine learning or AI model trained on data. Therefore, the concept of a "training set" is not applicable here.

9. How the Ground Truth for the Training Set Was Established

As there is no training set, this question is not applicable.

Summary of Missing Information:

• Explicit, pre-defined "acceptance criteria" thresholds.
• Specific numerical sample size for the tests (e.g., how many "multiple targets" were used).
• Details on the methodology of the "Monte Carlo tests and test calculations."
• Involvement of human experts in establishing ground truth for device performance.
• Any form of clinical study or MRMC study.
• Information related to machine learning/AI (training set, validation set, etc.) as the device does not appear to be an AI-driven diagnostic system.

Ask a specific question about this device

Not Found

MIDCO has recently developed a quality Couchmount System (Patient Head Support System) for use in radiosurgery. This couchmount system complements the cass collimator set and enables MIDCO to provide its customers with a full set of instrumentation necessary for radiosurgery. The design of this couchmount is such that it will fit most linear accelerators with only slight modifications to the couchmount adapter assembly. The cass Couchmount System has six axes of adjustment which allows for easy setup with the Linac couch/gantry system. An additional feature of the system is a unique laser measurement apparatus for precisely measuring an isocenter of a target volume for Linac-based radiosurgery/stereotactic radiotherapy. These two features also allow for the correction of alignment errors during treatment planning setup, such as errors inherent in the use of room lasers and errors due to couch shifts during patient positioning. It will also give an index of gantry sag or misalignment. Most commercially available stereotactic headrings can be mounted to the cass Couchmount System by the use of a stereotactic frame holder made specifically for the headring. Although most headrings are similar, each has a slightly different adapter plate which rigidly holds the headring. The stereotactic localization features of most frames are similar, differing mainly in the organization of the frame's coordinate system and its mechanical dimensions.

Here's a breakdown of the acceptance criteria and study information for the cass Linac Radiosurgery Hardware Couchmount Stereotactic Frame Support System, based on the provided text:

Acceptance Criteria and Device Performance

Study Details

1. Sample Size used for the test set and the data provenance:

   • Sample Size:
     • For the Lutz method test: "random phantom targets throughout the extremes of the coordinate system of the Leksell frame and BRW frame" were set up. No specific number is given, but it implies a range of targets.
     • For the overall system accuracy (humanoid phantom and dosimetry film): A single "humanoid phantom" was used, with a target point radiated.
     • For port film tests: "various predetermined target sites" were used. No specific number is given.
   • Data Provenance: The tests were conducted using a Varian 2100 C Linac, which is a common radiation therapy machine. The data is prospective, generated specifically for these tests by MIDCO and its consultants/instructors. There's no mention of specific countries of origin beyond the machine type.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
   The document does not explicitly state the number or specific qualifications of experts used to establish the ground truth for the test set. However, it indicates involvement of:

   • "appropriate consultants and instructors" from MIDCO for on-site instructions.
   • "radiation oncologists and radiation physicists" at each institution being "ultimately responsible for accurate measurements and gathering of data for the use of this system."
   • The studies cited (Lutz, Serago, et al.) are foundational in the field, implying that the ground truth methodology is based on established scientific and medical consensus within the radiosurgery community, as recognized by qualified physicists and clinicians.

3. Adjudication method for the test set:
   The document does not describe a formal "adjudication method" in the sense of multiple independent reviewers resolving discrepancies for the test set results. The results (e.g., error ranges for Dx, Dy, Dz displacements) appear to be direct measurements from the phantom studies. The methodology relies on established protocols from cited literature (Lutz method, Serago et al. method), which inherently incorporate methods for accurate measurement and calculation of discrepancies.

4. 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:
   No, an MRMC comparative effectiveness study involving human readers and AI assistance was not done. This device is a hardware system (couchmount and collimators) for radiosurgery, not an AI or imaging diagnostic tool that would typically involve human readers interpreting output.

5. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
   This question is not entirely applicable as the device is a hardware system. However, the performance reported (e.g., accuracy measurements like 0.48 mm ± 0.262 mm) represents the "standalone" mechanical accuracy of the system (Linac + collimators + couchmount) as configured and operated according to established protocols, without additional human interpretive input influencing the measurement of accuracy itself. The laser measurement system is an automated component for precise targeting. While humans operate the system, the reported accuracies are objective measurements of the system's physical performance.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
   The ground truth for the mechanical accuracy tests was established through phantom studies and dosimetry film analysis.

   • Lutz method: Uses a phantom pointer to simulate test targets at known stereotactic coordinates. Radiographic images are then taken, and x, y, z displacements are measured against the known phantom target positions.
   • Overall accuracy test: A humanoid phantom with a known target point is radiated, and the isocenter of the multiple intersecting beams is compared to the known position of the phantom target point indicator.
   • Port film tests: Predetermined target sites are set (aided by the Laser Measurement System), and then A-P and lateral port films are used to verify the actual versus intended target locations.
   • This is a form of empirical ground truth based on physical measurements against precisely known phantom positions.

7. The sample size for the training set:
   The document does not describe a "training set" in the context of machine learning. This device is a mechanical system, not an AI or software algorithm that requires a training set of data. The development process involved engineering design, prototyping, and testing, not machine learning model training.

8. How the ground truth for the training set was established:
   As there is no training set mentioned for this hardware device, this question is not applicable.

Ask a specific question about this device