(169 days)
Although intended primarily for use during Radiological Interventional and Special Procedures, the Skin Dose Monitor can be used whenever there is an interest in knowing patient skin dose. .
The primary purpose of the product is to monitor beam entry skin dose within the radiation beam, where there may be a risk of skin burns or cancers dur to extremely high doses.
In these situations the beam direction is fixed for a major part of the procedure and the sensor siting is obvious.
If the Skin Dose Monitor is to be used for other applications such as dose monitoring of a pregnant woman during general radiological procedures or monitoring doses during fluoroscopic guided surgery, the sensor site may be less obvious. Under these circumstances the sensor might be mounted on the X-Ray collimator face.
The real time display of dose may be used to indicate the need to take action to avoid excessive dose to one area of skin by changing the beam direction. The rate indicating LED provides a means to take action which will keep dosage per minute during fluoroscopy at the minimum level needed to ensure acceptable images.
The Skin Dose Monitor is also an effective tool for use during staff training or when benchmark protocols are being established for new procedures.
Contra indications for use are when the radiation energy or doserate being used fall outside the Skin Dose Monitor's specification, or where the small artefact he image (1 sq. mm), due to the sensor, is unacceptable. f
attention is drawn to the user for the need to gas sterilize sensors between applications in accordance with local infection control practice.
Skin Dose Monitor consists of the model 104–101 The Instrument complete with couch mounting bracket and QA Test Box. The 120 limited re-use sensor is also part of the system.
The sensor consists of a scintillating crystal which partially converts absorbed ionizing radiation into visible light. A length of radio translucent optical fiber transports the emitted light to the 104-101 instrument. The light is converted to an electrical current within the instrument and following scaling and integrating, is displayed on an LCD display in Grays or Rads. The instrument is battery powered and the displayed reading is retained when power is switched off.
The provided text describes a medical device called the "Skin Dose Monitor" (SDM) and its comparison to a predicate device. However, it does not contain a table of acceptance criteria nor a comprehensive study report that proves the device meets specific acceptance criteria in the format requested.
Instead, the document details:
- A description of the SDM and its intended use.
- A comparison of technical features with a predicate device (In Vivo Dosimeter) and justifications for differences based on intended use (diagnostic vs. therapy).
- Limited clinical and non-clinical performance assessments focused on electromagnetic compatibility, precision/stability comparison with industry standards, and skin adhesive effectiveness/safety.
- The FDA's 510(k) clearance letter for the device, indicating substantial equivalence to a predicate device.
- Indications for Use.
Based on the provided text, here's an attempt to answer the questions, highlighting what is not available in the document:
1. Table of acceptance criteria and the reported device performance
| Acceptance Criteria (Explicitly Stated in Document) | Reported Device Performance |
|---|---|
| Precision (for skin dose monitoring) | 10% (considered acceptable) |
| Stability (with expected changes in ambient temperature) | Sufficient (confirmed by comparisons with industry standard Ion chamber and diode dose measuring systems) |
| Electromagnetic Radiation Generation | Neither generates |
| Affected by Electromagnetic Radiation (typical room levels) | Not affected |
| Adhesive effectiveness (adhesion duration) | Adequately held in place for a number of hours |
| Adhesive safety (ease of removal, skin irritation) | Removed without undue discomfort, no signs of causing skin irritation |
| Sensor size (image artifact) | 1 sq. mm (acceptable artifact) |
| Radiation energy/dose rate | Must fall within SDM's specification (no specific range given) |
Note: The document states that "precision of 1% could be achieved with careful local physics calibration" but "10% is considered acceptable for skin dose monitoring." This implies that 10% is the practical acceptance criterion for precision in the intended use case.
2. Sample size used for the test set and the data provenance
- Test set sample size:
- For precision and stability (non-clinical): Not explicitly stated. The text mentions "Extensive measurements have been carried out" and "Comparisons have been made with industry standard Ion chamber and diode dose measuring systems," but the number of measurements or devices tested is not provided.
- For adhesive effectiveness/safety (clinical): "a number of volunteers." The specific number is not provided.
- Data provenance:
- Country of origin: Not specified.
- Retrospective or prospective:
- Non-clinical tests (precision, stability, EMC) seem to be prospective testing carried out by the manufacturer.
- Clinical tests (adhesive) were prospective, involving volunteers.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Number of experts: Not specified in the provided text.
- Qualifications of experts: Not specified.
- For the non-clinical tests (precision, stability), the "industry standard Ion chamber and diode dose measuring systems" implicitly serve as a reference or "ground truth," but who established that ground truth (e.g., how their readings were verified) is not detailed.
- For the clinical adhesive test, the "material manufacturer" carried out tests, which were "confirmed" by McMahon Medical's tests. This suggests internal expertise or a reliance on the adhesive manufacturer's data, but specific expert qualifications are not mentioned.
4. Adjudication method for the test set
- No formal adjudication method (like 2+1, 3+1 consensus) is described or implied for any of the performance assessments in the provided text. The non-clinical tests appear to be direct comparisons to established measurement standards, and the clinical adhesive test involved observation by the company staff.
5. 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. The Skin Dose Monitor is a direct measurement device, not an AI-assisted diagnostic tool for human readers. Therefore, an MRMC comparative effectiveness study involving human readers and AI assistance is not applicable and was not performed according to the provided text.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Yes, implicitly. The reported performance characteristics (precision, stability, EMC) describe the standalone performance of the device itself (hardware and its internal processing), independent of human interpretation or interaction during the measurement process. The device provides a direct digital readout.
7. The type of ground truth used
- For non-clinical performance (precision, stability): Comparison to "industry standard Ion chamber and diode dose measuring systems" served as the reference or ground truth. These are considered established, accurate methods for dose measurement.
- For non-clinical performance (EMC): Compliance with accepted standards for electromagnetic compatibility would be the ground truth, though the specific standards aren't listed, just that the device "neither generates Electromagnetic Radiation, or is affected by levels of electromagnetic radiation found in the typical radiological examination room."
- For clinical performance (adhesive): Observation of physical outcomes (adhesion, ease of removal, skin irritation) on volunteers, referencing "tests carried out by the material manufacturer." This is empirical observation of an outcome.
8. The sample size for the training set
- Not applicable / Not specified. The Skin Dose Monitor is described as a hardware device with an internal processing unit, not a machine learning or AI algorithm that requires a "training set" in the conventional sense. Its "calibration" would involve physical adjustments and validation against known radiation sources, rather than data-driven model training.
9. How the ground truth for the training set was established
- Not applicable / Not specified. As mentioned above, the concept of a "training set" and establishing ground truth for it does not apply to this device based on the provided information.
§ 892.1650 Image-intensified fluoroscopic x-ray system.
(a)
Identification. An image-intensified fluoroscopic x-ray system is a device intended to visualize anatomical structures by converting a pattern of x-radiation into a visible image through electronic amplification. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II (special controls). An anthrogram tray or radiology dental tray intended for use with an image-intensified fluoroscopic x-ray system only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9. In addition, when intended as an accessory to the device described in paragraph (a) of this section, the fluoroscopic compression device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.