(111 days)
The Ionization Chamber model 1041 is intended for the purpose of calibrating and measuring the ionizing radiation output from medical radiation therapy machines. This includes beam scanning as well as absolute dose calibration.
The Sun Nuclear model 1041 "SUN125c" is a waterproof, fully-guarded, cylindrical "thimble" type ionization chamber constructed primarily of ABS plastic. The chamber is mounted to a lownoise, high impedance triaxial cable which is terminated with either a bayonet (BNC) or threaded triaxial (TNC) connector. The ionization volume of the chamber is 0.125 cc, which is appropriate for beam scanning and absolute dose measurements. This active volume is vented to the atmosphere through the cable sheath, allowing for conventional air density corrections.
This 510(k) premarket notification describes the Sun 125c Ionization Chamber (model 1041), a medical device intended for calibrating and measuring ionizing radiation output from medical radiation therapy machines, including beam scanning and absolute dose calibration. It does not contain information about studies with patient data, AI/human reader performance, or ground truth establishment in a medical diagnostic context. The submission focuses on device safety and equivalence to a predicate device based on engineering principles and performance specifications.
Here's an analysis based on the provided text, addressing the points where information is available:
1. Table of Acceptance Criteria and Reported Device Performance
The submission does not explicitly state acceptance criteria in the form of a detailed table or report a study with performance metrics like accuracy, sensitivity, or specificity in a clinical diagnostic context. Instead, the "acceptance criteria" are implied by the comparison to a predicate device and the demonstration of similar functional principles and safety.
The reported "device performance" is primarily characterized by its design specifications and functionalities, as well as its similarity to the predicate.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Works on principles of externally generated voltage across ionization volume | "Application of an externally generated voltage across the ionization volume." |
| Collects ion current on a central electrode | "Collection of ion current on a central electrode..." |
| Achieves a dosimetric response close to that of water | "Achieve a dosimetric response close to that of water." |
| Atmospheric communication allowing air density corrections | "Atmospheric communication that allows air density correction." |
| Waterproof design | "Waterproof ionization chamber." |
| Appropriate for beam scanning and absolute dose measurements | "The chamber is... appropriate for beam scanning and absolute dose measurements." |
| Does not raise safety and effectiveness issues compared to predicate | "The indications for use, design, materials, manufacturing, and specifications of the Sun125c ionization chamber does not raise any issues with regards to safety and effectiveness." |
2. Sample Size Used for the Test Set and Data Provenance
This information is not provided in the document. The submission focuses on the technical specifications and equivalence of the device, not on clinical performance studies involving patient data or a specific "test set" in the context of diagnostic accuracy.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
This information is not provided as the device is not for diagnostic interpretation of medical data where expert radiologists or similar specialists would establish ground truth.
4. Adjudication Method for the Test Set
This information is not provided as there is no mention of a diagnostic test set requiring adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not performed or mentioned in this submission. This type of study is relevant for diagnostic devices that involve human interpretation of images or data, which is not the primary function of this ionization chamber.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
No, a standalone algorithm performance study was not performed or mentioned. This device is a physical instrument for measurement, not an AI algorithm.
7. The Type of Ground Truth Used
The concept of "ground truth" in this context is based on established physics principles of radiation dosimetry and metrology. The "truth" is derived from calibrated standards and known physical properties, not from pathology, outcomes data, or expert consensus in a diagnostic sense. The device is validated against the expected physical behavior of an ionization chamber and its ability to measure radiation accurately according to these principles.
8. The Sample Size for the Training Set
This information is not applicable and not provided. This device is a physical instrument, not a machine learning model that requires a "training set."
9. How the Ground Truth for the Training Set Was Established
This information is not applicable and not provided for the same reasons as point 8.
§ 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.