(84 days)
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.
| Feature / Metric | Predicate Device 1 (Elekta Stereotactic Body Frame) | Predicate Device 2 (Howmedica Extracranial Radiotherapy System) | BodyLoc™ (MIDCO®) Reported Performance | Implicit Acceptance Criteria / Conclusion (based on "substantially equivalent") |
|---|---|---|---|---|
| CT Localization error in the transversal plane (x-axis, y-axis) | Mean 3.1 mm | Mean 0.98 + 0.22 mm | Mean 0.5095 + 0.1058 mm | Better than both predicate devices. |
| CT localization error in the longitudinal plane (z-axis) | Range, 2-7 mm | Range, 0.9-3.5 mm | Range, 0.41-2.10 mm | Better than both predicate devices. |
| LINAC Set-up Error | Approximately 10 mm | Approximately 2.5 mm | Approximately 3.0 mm | Similar to Predicate 2, significantly better than Predicate 1. |
| Construction Material/Attenuation Coefficient (cm^-1) | Laminate of wood and plastic, 0.0467 cm^-1 | Carbon fiber composite, Approximately 0.5 cm^-1 | Polycarbonate, 0.029 cm^-1 | Lower attenuation than both predicate devices (implies less interference with radiation). |
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.
§ 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.