The XRpad2 4343 HWC-M, when used with a radiographic imaging system, is indicated for use in generating radiographic images of human anatomy for diagnostic X-ray procedures, wherever conventional screen-film (SF), digital radiography (DR), or computed radiography (CR) systems may be used. It is not intended for mammographic use.
Device Story
Wireless, cassette-sized, flat panel X-ray detector; fits into standard table or wall-stand Bucky. Input: X-ray radiation; amorphous silicon flat panel with directly deposited CsI:Tl scintillator converts X-rays to digital signals. Output: Digital radiographic images transmitted to host workstation via IP network. Operated by clinicians in diagnostic imaging environments. Device integrates with X-ray systems; uses X-ray Imaging Software Library (XISL) for detector control, configuration, and image acquisition. Output used by healthcare providers for diagnostic decision-making. Benefits: Enables digital radiography workflow, replacing traditional film-screen systems.
Clinical Evidence
No clinical data. Substantial equivalence demonstrated via bench testing only, including compliance with IEC/ISO standards for medical safety, EMC, and biocompatibility. Performance attributes (MTF, DQE) compared to predicate.
Technological Characteristics
Amorphous silicon flat panel with directly deposited CsI:Tl scintillator; carbon-fiber and aluminum enclosure. Dimensions: 460 mm x 460 mm x 15.5 mm. Connectivity: Gb Ethernet or 802.11n WiFi (5.15-5.85 GHz). Power: External supply or battery. X-ray sync via trigger lines or Automatic Exposure Detection. Software: XISL library (C/C++).
Indications for Use
Indicated for generating radiographic images of human anatomy for diagnostic X-ray procedures in clinical settings where conventional SF, DR, or CR systems are used. Not intended for mammographic use.
Regulatory Classification
Identification
A stationary x-ray system is a permanently installed diagnostic system intended to generate and control x-rays for examination of various anatomical regions. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.
Special Controls
*Classification.* Class II (special controls). A radiographic contrast tray or radiology diagnostic kit intended for use with a stationary 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.
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Image /page/0/Picture/0 description: The image contains the logos of the Department of Health and Human Services (HHS) and the Food and Drug Administration (FDA). The HHS logo is on the left, and the FDA logo is on the right. The FDA logo includes the FDA acronym in a blue square, followed by the words "U.S. FOOD & DRUG ADMINISTRATION" in blue text.
July 3, 2018
Varex Imaging Corporation % Mr. Paul Sawicki Director, Quality Assurance and Regulatory Affairs 2175 Mission College Blvd. SANTA CLARA CA 95054
Re: K181526
Trade/Device Name: XRpad2 4343 HWC-M Regulation Number: 21 CFR 892.1680 Regulation Name: Stationary x-ray system Regulatory Class: II Product Code: MOB Dated: June 7, 2018 Received: June 11, 2018
Dear Mr. Sawicki:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820);
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## Page 2 - Mr. Paul Sawicki
and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely.
Hsl 2. Mils
Robert Ochs, Ph.D. Director Division of Radiological Health Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health
Enclosure
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DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration
# Indications for Use
Form Approved: OMB No. 0910-0120 Expiration Date: 06/30/2020 See PRA Statement below.
510(k) Number (if known)
K181526
Device Name
XRpad2 4343 HWC-M
Indications for Use (Describe)
The XRpad2 4343 HWC-M, when used with a radiographic imaging system, is indicated for use in generating radiographic images of human anatomy for diagnostic X-ray procedures, wherever conventional screen-film (SF), digital radiography (DR), or computed radiography (CR) systems may be used. It is not intended for mammographic use.
Type of Use (Select one or both, as applicable)
| <span> <b> </b> Prescription Use (Part 21 CFR 801 Subpart D) </span> | <span> <b> </b> Over-The-Counter Use (21 CFR 801 Subpart C) </span> |
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Image /page/3/Picture/1 description: The image is a logo for Varex Imaging. The logo consists of the letter V, which is made up of several vertical lines in different shades of green and blue. To the right of the V is the word "VAREX" in blue, and below that is the word "IMAGING" in a smaller font.
# 510(K) SUMMARY
## XRpad2 4343 HWC-M Flat Panel Detector
This summary of 510(k) safety and effectiveness information is supplied in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.
The assigned 510(k) number is: K181526
Date: June 27, 2018
| Submitted By: | Varex Imaging Corporation<br>2175 Mission College Blvd.<br>Santa Clara, CA 95054<br>U.S.A. |
|-------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Contact Person: | Paul Sawicki<br>Director, Quality Assurance and Regulatory Affairs<br>Tel. 408-469-6462<br>Fax. 408-969-6493<br>E-mail: paul.sawicki@vareximaging.com |
| Device Name: | XRpad2 4343 HWC-M Flat Panel Detector |
| Classification: | Product Code: MQB<br>Classification Name: Solid state X-ray imager (flat panel/digital imager)<br>Regulation Name: Stationary X-ray system<br>Classification Regulation: 21 CFR 892.1680 |
| Predicate Device: | XRpad 4336 HWC-M Flat Panel Detector<br>510(k) Clearance: K161966; September 8, 2016<br>Product Code: MQB<br>Classification Name: Solid state X-ray imager (flat panel/digital imager)<br>Regulation Name: Stationary X-ray system |
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Image /page/4/Picture/1 description: The image is a logo for Varex Imaging. The logo consists of the word "VAREX" in blue, with the word "IMAGING" in smaller letters below it. To the left of the word "VAREX" are several vertical lines in different colors, including blue, green, and yellow. The logo is simple and modern, and the colors are bright and eye-catching.
### Device Description:
The XRpad2 4343 HWC-M is a wireless, lightweight, cassette-sized, flat panel X-ray detector for digital radiography. It fits into a conventional table or wall-stand Bucky, just like a film-screen cassette. The X-ray detector consists of an amorphous silicon flat panel with a directly deposited Csl:Tl scintillator and dedicated read-out, scan, and control electronics, all packaged in a carbon-fiber and aluminum enclosure. The outside dimensions of the detector are 460 mm × 460 mm × 15.5 mm, which fits into a standard X-ray cassette Bucky.
The detector can be integrated with an X-ray system to enable digital radiography. The following accessories are available for the XRpad2 4343 HWC-M:
- XRpad LBC-2 (Lithium Battery Charger)
- . XRpad IPU-2 (Interface and Power Unit)
- . XRpad LPT2 Detector Cable
- . XRpad Protective Insert
- AC Cable IEC 60320 C13 DE
- AC Cable IEC 60320 C13 US
- Trigger Cable 5 m/16.5 ft.
- . Trigger Cable 20 m/65.5 ft.
- GigE Interface Cable 7.6 m/25 ft.
- . GigE Interface Cable 15.25 m/50 ft.
#### Device Software:
The XRpad2 4343 HWC-M device, like the predicate, relies on the X-ray Imaging Software Library (XISL), to control the detector from the host computer. The XISL is a C/C++-coded software library that provides parameterized functions to interface the device to a host work station via an IP Network connection. By use of the application programming interface (API) of XISL one can acquire images and configure all use functions of the XRpad2 4343 HWC-M detector.
### Indications for Use:
The XRpad2 4343 HWC-M, when used with a radiographic imaging system, is indicated for use in generating radiographic images of human anatomy for diagnostic X-ray procedures, wherever conventional screen-film (SF), digital radiography (DR), or computed radiography (CR) systems may be used. It is not intended for mammographic use.
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Image /page/5/Picture/0 description: The image is the logo for Varex Imaging. The logo has a stylized V made of four lines, with the leftmost line being dark blue, the next two lines being green, and the rightmost line being light green. To the right of the stylized V is the text "VAREX" in dark blue, and below that is the text "IMAGING" in a smaller font, also in dark blue.
# Comparison Chart:
| | Model | Proposed Model |
|---------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------|
| Characteristics | XRpad2 4336 HWC-M<br>(K161966) | XRpad2 4343 HWC-M |
| Intended Use /<br>Indications for Use | The XRpad 4336 HWC-M when used<br>with a radiographic imaging system, is<br>indicated for use in generating<br>radiographic images of human<br>anatomy for diagnostic X-ray<br>procedures, wherever conventional<br>screen-film (SF), digital radiography<br>(DR), or computed radiography (CR)<br>systems may be used. It is not<br>intended for mammographic use. | Same |
| Panel | Single substrate amorphous silicon<br>active TFT/diode array | Same |
| Scintillator | Direct deposition CsI:Tl | Same |
| Pixel pitch | 100 μm | Same |
| Pixel matrix | 3524 × 4288 | 4288 × 4288 |
| Limiting resolution | 5 lp/mm | Same |
| Binning capable | 2 × 2 binning for 200 µm | Same |
| Data transmit area | 352 mm × 429 mm | 429 mm × 429 mm |
| External dimensions<br>(w × l × h) | 384 mm × 460 mm × 15.5 mm | 460 mm × 460 mm × 15.5 mm |
| Weight | 3.2 kg | 3.8 kg |
| Housing material | Aluminum with carbon-fiber | Same |
| Finish | Matte carbon-fiber front with white<br>silk-screen active area markers | Same |
| Communication interface | Gb Ethernet or 802.11n WiFi | Same |
| WiFi band | 5.15 - 5.85 GHz | Same |
| X-ray synchronization<br>interface | Dedicated trigger in/out signal lines or<br>Automatic Exposure Detection | Same |
| Power | External power supply or battery | Same |
| Software library | X-ray Imaging Software Library (XISL),<br>which provides control of detector<br>configuration and image acquisitions<br>from a host computer | Same |
| Software operating system | Windows and Linux OS | Same |
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Image /page/6/Picture/0 description: The image shows the logo for Varex Imaging. The logo consists of the letter V, which is made up of four vertical lines in different shades of blue and green. To the right of the V is the word "VAREX" in blue, and below that is the word "IMAGING" in smaller, gray letters. The logo is simple and modern, and the colors are calming and professional.
#### Summary of Studies:
The proposed new device (XRpad2 4343 HWC-M) and the predicate device (XRpad2 4336 HWC-M) utilize similar technology and materials, are similar in design and construction, and have the same intended use. The construction and physical characteristics of the two devices are similar. The difference is related to a 76 mm increase in the width dimension of the proposed device, which does not impact image quality.
The XRpad2 4343 HWC-M flat panel detector has successfully completed internal non-clinical testing, and complies with IEC and ISO standards and regulations related to medical safety, EMC, and bio-compatibility. A clinical study was not required for the XRpad2 4343 HWC-M device. Taking into consideration the similarities in construction and physical characteristics of the XRpad2 4343 HWC-M to the predicate device, substantial equivalence of imaging performance between the two XRpad2 flat panel detectors can be demonstrated by a comparison of the non-clinical testing results only.
#### Summary of Design Control and Risk Management:
The XRpad2 4343 HWC-M flat panel X-ray detector is a modification of the XRpad2 4336 HWC-M (K161966). The modifications are related to an increase in the width dimension of the device, and do not impact image quality.
The risks and hazardous impacts of the device modification were analyzed by FMEA methodology. The specific risk control and protective measures to mitigate the risks from the modification were reviewed as part of product design. The overall assessment concluded that all identified risks and hazardous conditions were successfully mitigated and accepted.
### Summary of Non-Clinical Data:
To demonstrate the equivalence of the XRpad2 4343 HWC-M to the predicate device, Varex Imaging has performed internal non-clinical testing and demonstrated compliance with accepted IEC and ISO standards and regulations. In addition, Varex Imaging has followed the non-clinical considerations outlined in the Guidance for the Submission of 510(k)'s for Solid State X-ray Imaging Devices, September, 2016. This testing demonstrated that critical image quality performance attributes, such as MTF and DQE, of the XRpad2 4343 HWC-M are comparable to the predicate device. The resulting data from the conducted non-clinical tests demonstrate substantial equivalence.
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Image /page/7/Picture/0 description: The image is a logo for Varex Imaging. The logo has the word "VAREX" in a sans-serif font, with the letters in a dark blue color, except for the "X" which is in green. Below the word "VAREX" is the word "IMAGING" in a smaller, sans-serif font, also in a dark blue color. To the left of the word "VAREX" is a stylized "V" made up of four vertical lines, with the first line in dark blue, the second line in green, the third line in yellow, and the fourth line in dark blue.
#### Substantial Equivalency:
The proposed device and predicate device (XRpad2 4336 HWC-M flat panel detector) both utilize similar technology and materials, are similar in design and construction, and have been shown to produce images of equivalent diagnostic quality. Both devices are intended for use in generating radiographic images of human anatomy for diagnostic X-ray procedures, wherever conventional screen-film (SF), digital radiography (DR), or computed radiography (CR) systems may be used. The devices are not intended for mammographic use. Both devices produce digital images which can be transmitted to imaging software of the X-ray unit.
#### Conclusion:
Similar to the predicate device, the XRpad2 4343 HWC-M has comparable performance and comply with similar operational standards. Potential hazards have been studied by a Risk Management Plan. The nonclinical verification and validation test results demonstrate that the XRpad2 4343 HWC-M complies with international and FDA recognized consensus standards and meets the acceptance criteria and is adequate for its intended use.
Based on the information supplied in this 510(k) Varex Imaging concludes, the XRpad2 4343 HWC-M is substantially equivalent to the currently marketed device, XRpad2 4336 HWC-M (K161966) in terms of safety and effectiveness.
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Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
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Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
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With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
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Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.