(41 days)
The LaserPro 16 is a desk top laser image digitizer intended to produce digital copies of radiological film in 10 bit gray scale. The digital copies are transmitted to a conventional based personal computer (PC) where they may be transmitted to a PACS (Picture Archiving and Communication System) or other networks to other medical facility sites.
The eRadLink LaserPro 16 is a digitizing scanner that converts radiographic film transparency images to digital format. This is accomplished by utilizing a laser beam light source and a proprietary sealed optic path. There are no internal lenses, mirrors, or electro-optic devices. The new technology provides superior image quality, requires no internal optics cleaning, no optical alignment and is inherently highly accurate and reliable. Film, from a minimum of 2 inches to a maximum of 14 inches in width and, from a minimum of 2 inches to a maximum of over 52 inches in length is driven passed the scanning laser beam by a clocked, stepping motor. Scanned data is electronically converted from analog to 16 bit digital gray scale and transmitted to the host computer in DICOM format.
Here's an analysis of the provided text regarding the Laser Film Digitizer (eRadLink LaserPro 16), focusing on acceptance criteria and the study that proves device performance:
1. Table of Acceptance Criteria and Reported Device Performance
The provided document (K020243) is a 510(k) Summary for a medical device. It focuses on demonstrating substantial equivalence to a predicate device rather than explicitly defining and meeting specific, quantitative acceptance criteria for safety and effectiveness in the way a clinical trial might.
The "Effectiveness" section [4] states:
"Program testing and calibration using Stoeffer T4110 gray-scale strip, linearity test patterns and typical x-ray film samples has demonstrated the LaserPro's 16's conformance to its defined specifications."
This sentence implies that the "defined specifications" are the acceptance criteria, and the testing performed confirms conformance. However, the specific numerical values of these "defined specifications" are not explicitly listed in the document as measurable acceptance criteria with corresponding performance results.
Instead, the document primarily compares the device's features and characteristics to a predicate device. If we were to infer "acceptance criteria" from the comparison, they would generally relate to matching or exceeding the capabilities of the predicate device.
Inferred "Acceptance Criteria" from Predicate Comparison and Reported Performance:
| Feature (Acceptance Criteria - inferred comparison to predicate) | Predicate Device (Lumiscan 75) Performance | eRadLink LaserPro 16 Reported Device Performance | Comments/Rationale for Inferred Criteria |
|---|---|---|---|
| Scan Size (min) | 7" x 7" | 2" x 2" | The LaserPro 16 meets/exceeds the minimum scan size of the predicate. Inferring an acceptance criterion of "at least as good as predicate." |
| Scan Size (max) | 14" x 36" | 14" x 15' (14" x 180") | The LaserPro 16 significantly exceeds the maximum scan size of the predicate. Inferring an acceptance criterion of "at least as good as predicate." |
| Spot Size | 100 um | 116 um | The LaserPro 16 has a slightly larger spot size (lower resolution capability) than the predicate. Without explicit justification, this might be a point of concern for some, but in a 510(k), it's deemed "substantially equivalent." Acceptance criteria implicitly allow for minor differences if overall safety and effectiveness are maintained. |
| Dynamic Range | 0.5 - 3.8 OD | 0.0-4.1 OD | The LaserPro 16 meets/exceeds the dynamic range of the predicate, offering a wider range. Inferring an acceptance criterion of "at least as good as predicate." |
| Gray Scale | 12 bits | 8, 12, or 16 bits | The LaserPro 16 meets/exceeds the gray scale capability of the predicate, offering more options. Inferring an acceptance criterion of "at least as good as predicate." |
| Digitizing Rate | 115 lines/sec | 100 lines/sec (16 bit gray scale) | The LaserPro 16 has a slightly slower digitizing rate at 16-bit gray scale, but the predicate rate (115 lines/sec) might be at a lower bit depth (e.g., 12-bit). If the predicate's 115 lines/sec was also at 16-bit, then the LaserPro is slightly below. However, the FDA found it substantially equivalent. |
| Pixel/mm | 10.09 | 8.6 | The LaserPro 16 has fewer pixels/mm (lower resolution) than the predicate (8.6 vs 10.09). Again, this is a minor difference that was accepted as part of substantial equivalence. |
| Conformance to "Defined Specifications" | N/A (Predicate has its own specs) | Demonstrated by program testing & calibration | This is the most direct statement of meeting criteria, but the specifications themselves are not detailed. |
| Safety Compliance | N/A (Predicate has its own compliance) | UL260, CSA 22.2, TUV, IEC 601-1 approved | The device must meet recognized safety standards. |
| EMT Requirements | N/A (Predicate has its own compliance) | CISPR 11 Class B for EMT requirements | The device must meet recognized electromagnetic compatibility standards. |
Study That Proves the Device Meets Acceptance Criteria:
The document describes the study in section (8) EFFECTIVENESS:
"Program testing and calibration using Stoeffer T4110 gray-scale strip, linearity test patterns and typical x-ray film samples has demonstrated the LaserPro's 16's conformance to its defined specifications."
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: Not explicitly stated. The description mentions "typical x-ray film samples" but does not quantify the number of samples used (e.g., number of films, number of images).
- Data Provenance: Not explicitly stated. The document does not specify the country of origin of the "typical x-ray film samples" or if they were retrospective or prospective. Given the context of a 510(k) submission for a digitizer, these would likely be existing, retrospective films.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- Number of Experts: Not mentioned.
- Qualifications of Experts: Not mentioned.
It's highly probable that for a device like a film digitizer, "ground truth" would be established by comparing the digitized output to the original film's properties (e.g., optical density, resolution, linearity) rather than relying on human interpretation of the digitized image for diagnostic accuracy comparisons at this stage of approval. Therefore, expert radiologists might not have been directly involved in establishing the "ground truth" for the technical performance of the digitizer itself.
4. Adjudication Method for the Test Set
- No adjudication method is mentioned, as the study described is technical validation of digitization performance against physical standards (gray-scale strips, linearity patterns) and "typical x-ray film samples," not a diagnostic study requiring human interpretation and consensus.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
- No Multi-Reader Multi-Case (MRMC) comparative effectiveness study was performed or described. The study focuses on the technical performance of the digitizer, not its impact on human reader performance or diagnostic accuracy. There is no mention of comparing human readers with AI assistance vs. without AI assistance.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study was Done
- Yes, a standalone study was done. The "Program testing and calibration" described in section (8) "EFFECTIVENESS" is a standalone evaluation of the device's technical specifications. The device, being a digitizer, is the algorithm/hardware combination that performs the digitization process. The study evaluates its output against known standards, independent of human interpretation or interaction beyond setting up the test.
7. The Type of Ground Truth Used
- The ground truth used appears to be based on technical standards and physical measurements.
- Stoeffer T4110 gray-scale strip: A standardized tool used to evaluate the gray-scale reproduction and dynamic range of imaging systems.
- Linearity test patterns: Used to assess the geometric accuracy and linearity of the digitization process.
- Typical x-ray film samples: These would have known optical densities, resolutions, and content, allowing for evaluation of how accurately the digitizer captures these features.
8. The Sample Size for the Training Set
- Not applicable. This device is a film digitizer, not an AI/ML algorithm that requires a "training set" in the conventional sense. Its "training" is in its design, engineering, and factory calibration to meet physical specifications, not in learning from a dataset.
9. How the Ground Truth for the Training Set was Established
- Not applicable. As explained above, there is no "training set" for a film digitizer in the context of the provided document. The ground truth for its calibration and validation relies on standardized physical references like the Stoeffer T4110 and linearity test patterns.
§ 892.2030 Medical image digitizer.
(a)
Identification. A medical image digitizer is a device intended to convert an analog medical image into a digital format. Examples include Iystems employing video frame grabbers, and scanners which use lasers or charge-coupled devices.(b)
Classification. Class II (special controls; voluntary standards—Digital Imaging and Communications in Medicine (DICOM) Std., Joint Photographic Experts Group (JPEG) Std.). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.