X-Ray Systems:

Third Party Review

Jabari Calliste, PhD

Center for Devices and Radiological Health (CDRH)

U.S. Food and Drug Administration
2

What to Know Before You Start

• Scientific understanding of x-ray systems

• “Evaluating Substantial Equivalence” guidance

The 510(k) Program: Evaluating Substantial Equivalence in Premarket Notifications [510(k)]

• Regulations, device-specific guidance 

documents and standards for x-ray systems
3

Key X-Ray

Standards and Guidances

Medical electrical equipment –

Part 2-54: Particular requirements for the basic safety and essential performance of X-ray 

equipment for radiography and radioscopy 

IEC 60601-2-54

IEC 62220-1-1

Medical electrical equipment – Characteristics of digital X-ray imaging devices –

Part 1-1: Determination of the detective quantum efficiency - Detectors used in radiographic 

imaging

Guidance

• Guidance for the Submission of 510(k)s for Solid State X-ray Imaging Devices

• Content of Premarket Submissions for Management of Cybersecurity in Medical Devices

• Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices

• Pediatric Information for X-ray Imaging Device Premarket Notifications

• Radio Frequency Wireless Technology in Medical Devices
4

Learning Objectives

Essential elements in review and documentation of 

510(k)s for x-ray systems

Understand

Know Relevant regulations, guidances, standards and 

terminology

Identify Potential premarket review items important to x-ray 

systems
5

Our New Device

• New stationary x-ray system

• Intended for adults and pediatrics

• Key Features:

– Generator

– X-ray tube

– Wireless detector

– Software: Autogrid, Low Dose 

Protocol (LDP)

– Claims: Image quality, Dose 

reduction Stationary x-ray system

Bucky stand

Floating table

X-ray tube, 

generator & 

collimator

Wireless detector
6

Classification Regulation and Product 

Codes for X-ray Systems

Regulation 

Number

Product 

Code

21 CFR 892

Radiological Devices

21 CFR 892.1680

Stationary X-ray System

21 CFR 892.1720

Mobile X-ray System

IZL

System, X-ray, Mobile

KPR

System, X-ray, Stationary

MQB

Solid State X-ray Imager 

(Flat Panel/Digital Imager)
7

Classification Regulation and Product 

Codes for X-ray Systems

Regulation 

Number

Product 

Code

21 CFR 892

Radiological Devices

21 CFR 892.1680

Stationary X-ray System

21 CFR 892.1720

Mobile X-ray System

IZL

System, X-ray, Mobile

KPR

System, X-ray, Stationary

MQB

Solid State X-ray Imager 

(Flat Panel/Digital Imager)
8

Steps to Determine 

Substantial Equivalence

Essential components of the submission Highlight & 

Document

Use Device 

Specific 

Documents FDA guidance and recognized standards

Focus on 

Differences

Between new and predicate device—

use 510(k) Decision Making Flowchart

510(k) Decision-Making Flowchart from The 510(k) Program: Evaluating Substantial Equivalence in Premarket Notifications [510(k)]
9

The 

“Evaluating 

Substantial 

Equivalence” 

Guidance 

Flowchart is 

Our 

Framework

Identify the new device 

and the predicate device 

NSE

Decision 1

Is the

predicate device legally 

marketed?

Decision 3

Do the devices

have the same

technological

characteristics?

Decision 4

Do the different

technological characteristics

of the devices raise different

questions

of safety and 

effectiveness?

Decision 5a

Are the methods

acceptable?

Decision 5b

Do the data

demonstrate substantial

equivalence?

Review all labeling and assure

that it is consistent with IFU 

statements.

Review design, materials, energy

source and other features of the 

devices.

Determine what questions of

safety and effectiveness the 

different technological 

characteristics raise.

Review the proposed scientific

methods for evaluating new/

different characteristics’ effects

on safety and effectiveness.

Evaluate performance data.

NSE

NSE NSE

NSE

SE SE

NO

YES

Decision 2

Do the devices

have the same

Intended use?

NO

YES

YES

NO

NO

NO

YES

NO

YES
10

Color-Coded Flowchart for Navigation

Identify the new 

device and the 

predicate device 

Decision 1

Is the predicate 

device legally 

marketed?

Decision 2

Do the devices have 

the same intended 

use?

Decision 3

Do the devices

have the same 

technological 

characteristics?

Decision 5a

Are the methods 

acceptable?

Decision 5b

Do the data 

demonstrate 

substantial 

equivalence?

Decision 4

Do the different

technological characteristics

of the devices raise different

questions of safety and

effectiveness?

Final Decision 

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We Will Walk Through A Memo Memo
12

Before Using the Flowchart

Where 

To 

Look

 CDRH Premarket Review Cover Sheet (Form FDA 3514)

 Cover letter

 510(k) summary 

 Substantial equivalence discussion 

What 

To 

Do

 Review purpose for 510(k) submission

 Ensure differences from predicate are clearly and consistently described 

 Verify product codes and regulation numbers for proposed and predicate devices

 Look for previously-related submissions from sponsor: 

 Check TPLC database for previous submissions for similar devices from sponsor (NSE, Q-Sub). 

 Check predicate for recalls using Recalls database

 Check MAUDE database for medical device reports (MDRs) associated with device type

What 

To 

Document

 Summary of purpose for the submission, including: 

 Device product code and regulation number

 Differences from the predicate

 Explanation of how related submission (if available) affects review of submission

 Explanation of how MDRs and/or recalls (if available) affect review of submission
13

Use MAUDE for MDR Search

• Always enter the device 

product code 

• Enter manufacturer names in 

part and full 

• Spelling matters and avoid 

plurals

Hints 

& 

Tips

Search Reminders

www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/search.CFM
14

Use Recalls Database 

Hints 

& 

Tips

Search Reminders

• Always enter the device 

product code

• Always enter 510(k) number of 

predicate device

• Enter name of recalling firm in 

part and full 

www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfRES/res.cfm
15

Before You Go Further!

Hints 

& 

Tips

CADx or CADe

• Computer-Aided Diagnostic or Detection

• Not eligible for Third-Party Review

• Require clinical evaluation

• Remove feature from Third-Party Submission

• New device example – CADe under “Software” section 
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Decision 1

Is the predicate 

device legally 

marketed?
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Decision 2

Do the devices 

have the same 

intended use?
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Look at Indications for Use (IFU) 

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Where 

To 

Look

 Indications for Use Statement (Form FDA 3881)

 Proposed labeling (510(k) summary, User manual, Brochures)

What 

To 

Do

 Check consistency of IFU throughout submission 

 Review details of IFU, intended population and prescription/over-the-counter information

 Review promotional material (including claims) in detail for any new indications.

What 

To 

Document

If different indications for use than predicate:

 Highlight differences and explain why they don't affect overall intended use

If no new indications for use:

 Document that indications are same as predicate

 Document that labeling is consistent with IFU.
19

Labeling Information

• Indications for use, Rx icon or prescription statement

• Quality Control manual

• Description of standards, quality criteria, or limits of acceptance for each monitored 

parameter

• Image quality and dosimetry performance testing information

• Integration information:

• other devices/components with which the device is compatible

• Review and evaluate all device specific claims 

Hints 

& 

Tips

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Labeling: Pediatric Information

• Description of special pediatric features

• Labeling information for pediatric use of X-ray imaging device

• Appropriate pediatric cautions/warnings and instructions for use

• This caution statement: “Use special care when imaging patients outside 

the typical adult size range”

Hints 

& 

Tips

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Labeling: Pediatric Information

• Memo should document:

• these findings

• risk assessment on pediatric use

• Sample Summary

• Appendix A of Pediatric Guidance

• Pediatric Information for X-ray Imaging Device Premarket Notifications

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Memo
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IFU Section

Comparison of Indications for Use

Subject

510(k) #: Rx/OTC: Rx 

Intended

Population

Adults

Only

Adults and

Pediatrics

Transitional 

Adolescent A 

Transitional 

Adolescent B Adolescent Child Infant Neonate/

Newborn

Yes        

No        

Unknown        

Indications for Use: The <device name> is a stationary/mobile x-ray system intended for use in general 

projection radiographic images of human anatomy for adults and pediatrics in all general-purpose diagnostic

procedures, excluding mammographic applications. 

Predicate(s) 

Submission#: Rx/OTC: Rx 

Intended Population: Adults 

Indications for Use: <Device name> is a stationery X-ray system intended for obtaining radiographic images of 

various portions of the human body in a clinical environment. 

The <device name> is not intended for mammography, angiography, interventional, or fluoroscopy use. 



• IFU statements are similar, except that proposed device explicitly lists pediatrics in intended population.

• Although IFU wording is different, intended use for general radiography applications is the same.

• However, in the proposed labeling a CADe/CADx feature for fracture detection and pulmonary 

contusion diagnosis was discovered. This labeling is not consistent with the IFU, and changes the 

intended use of proposed device.

This is a deficiency. 

Memo
23

Labeling Information

Prescription statement included: Yes 

Indications for Use consistent with IFU page: Yes 

Appropriate Contraindications, Warnings, Precautions & Adverse Events: Yes 

Instructions in accordance with guidance: Yes 

Appropriate labeling inside device: Yes 

Appropriate labeling outside device: Yes 

Appropriate instructions for use labeling: Yes 

In both the hardware and software documents, the sponsor provided the following information:

• Manufacturer’s Contact Information 

• Prescription Use Statement 

• Intended Use / Indications for Use 

• Relevant notes, cautions, warnings, and/or contraindications 

• Symbols (with description) 

• Device Descriptions 

• Hardware Requirement (software) 

• Accessories 

• Directions for Use (check for radiation safety information) 

• Description of quality assurance tests (and action limits) 

Memo Summary of Labeling

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• Performance information for the flat-panel digital imagers, and the 

QC/maintenance information

• Sponsor did not follow FDA final guidance “Pediatric Information for X-ray 

Imaging Device Premarket Notifications”

 This is a deficiency.

Memo Labeling Review

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Memo Review of Claims

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• At equivalent image quality, the device results in 50% less dose to the patient. 

• Reviewer Comment:

• Sponsor provided simple Likert-type scoring of clinical images to support 

quantitative claim

• Study did not include assessment of physical parameters.

• Study is not accurate to support claim. A more carefully designed clinical 

study with a clearly established baseline and endpoints would be 

needed. For example ROC curves would be an acceptable analysis 

acceptance method. This is a deficiency.

• Conclusion: Claim is unacceptable.
26

Example Resolution

Example Deficiency:

In your proposed labeling section, you provided a quantitative dose reduction claim for your new device and you 

have provided a Likert-type study to support this. However at this time, the Agency finds the overall methodology 

of your data analysis, including the simple Likert scoring of clinical images to not support the quantitative claim. 

You have not established that the baseline dose (prior to application of the new post-processing feature) is 

optimized. As a result, both the higher dose and lower dose images may have been collected on a part of a dose 

response curve where the reader cannot distinguish between the images to within error. Therefore to establish 

that your new post-processing feature enables dose reduction by improving image quality, a more carefully 

designed reader study with predefined endpoints and a carefully established dose baseline is needed to support 

this claim; ROC is an example of an acceptable type of analysis method. We strongly suggest that you remove the 

claim and submit a pre-submission discussion to address data collection and analysis methods in a future 510(k). 

This information needs to be corrected to provide the end user with accurate device performance data. 

Sponsor response in supplemental documentation:

We have removed the dose reduction claim from this submission.

This is adequate.
27

• Image quality: “At equivalent dose, the device results in 41% improvement in 

image quality.” 

• Reviewer comments: 

• No clear point of comparison for claim or basis explained in labeling

• Claim based on noise reduction

• only one measure associated with image quality

• Observation of images by qualified radiologist cannot be quantified.

• Conclusion: This is unacceptable. Sponsor removed claim. 

Memo Review of Claims

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• Contrast: “AutoGrid is optional feature that improves visibility of diagnostic 

chest and abdomen x-ray images by decreasing scatter radiation when grid is 

not used in image acquisition.”

• Reviewer comments: 

• Claims are substantiated with a statement from a board-certified 

radiologist on an anthropomorphic phantom study . See performance 

testing section.

• Conclusion: Claim is acceptable. 

Memo Review of Claims

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• Clinical: Superior detection of simple (non-displaced) fractures, displaced 

fractures, and pulmonary contusion detection in standard PA (posterior 

anterior) chest x-rays compared to conventional chest x-rays.

• Reviewer comments: 

• The claim is associated with the CADe/CADx feature which is not 

supported by any data.

• Deficiency issued to sponsor

• Conclusion: Claim is unacceptable, sponsor removed claim. 

Memo Review of Claims

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Decision 3

Do the devices

have the same 

technological 

characteristics?
31

Describe Device and

Compare Technology

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Where 

To 

Look

 Device description section

 Substantial equivalence discussion

 Software section

What 

To 

Do

 Review all components of entire x-ray system.

 Check to see whether components of x-ray system have been previously cleared.

 Compare components with predicate device, especially:

 X-ray generator specifications

 Detector type and specifications

 Image acquisition and post processing software

What 

To 

Document

 Summary description of x-ray system, indicating both hardware and software components

 More detailed explanation of new/modified features, focusing on features different from predicate. 

 Accompanying 510(k) numbers for previously-cleared components
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Summary Description 

of New Device

Device Description Information

Device uses software/firmware: Yes 

• Connection Types: Cloud, Network, Wireless

Device or component needs sterilization: No 

Environments of Use: Professional Healthcare Facility 

The Device/System is electrical: Yes, it is mains powered Only 

• Wireless Technology is used: Yes 

Radiographic x-ray system consisting of a tube 

rail stand, a bucky stand, and a floating table, a 

tube, a collimator, wireless digital detector, and a 

generator. Sponsor states that the device is a 

floor-mounted stand, table, and a wall stand.

Memo
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Differences Between 

New and Predicate Devices

• Addition of wireless detectors (in new device)

• Addition of post-processing options to a software package (modified)

• Key: image quality improvement and dose reduction claims associated with new 

post-processing functions.

• Autogrid (new feature)

• Low Dose Protocol (new feature)

• Different generator power options

Memo
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Common Occurrences

and Best Practices

Memo

• Issue: Sponsor state that software is exactly the same as predicate device

 Clarify with sponsor that software is has not changed to accommodate 

new hardware

• Issue: Hardware components are different from those of predicate

 Focus on integration testing of hardware components with software
35

Decision 4

Do the different

technological characteristics

of the devices raise different

questions of safety and

effectiveness?

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36

Focus on Differences in

Technological Comparison

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Where 

To 

Look

 Device description section

 Substantial equivalence discussion

 Software section

What 

To 

Do

 For each new / modified component of x-ray system compared to the predicate, assess whether there are new 

questions of safety and effectiveness

What 

To 

Document

 Document questions raised by technological characteristics not applicable to predicate

 Explanation of why new / modified components do / do not raise any different questions of safety and 

effectiveness to the x-ray system
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Characteristics New Device Predicate Device

X-ray Generator

kV range 40-150 kV 40 – 125 kV

Milli ampere sec (mAs) range 0.1 – 320 mAs 0.1 – 320 mAs

Milliampere range 50 – 400 mA 50 – 320 mA

Memo

• X-ray generators have different kV and mA ranges resulting in different 

power ratings.

• Though increased, kV and mA ranges for the new device are within the 

appropriate ranges for imaging of the human anatomy.

• Does not raise new questions of safety and effectiveness. 
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Characteristic New Device Predicate Device

Detector

Type Digital wireless flat 

detector Digital wired flat detector

Scintillator gadolinium oxysulfide

(GadOx - Gd2O2S) Cesium Iodide (CsI)

Detector size 15” x 18” 15” x 18”

Active area 14.6” x 17.6” 14.3” x 17.3”

Pixel size 136 μm 148 μm

MTF @ 50% 2.5 lp/mm 3.0 lp/mm

DQE 1.0 mm-1 = 20%

2.0 mm-1 = 10%

1.0 mm-1 = 26%

2.0 mm-1 = 12%

• New device uses a wireless detector with GadOx as scintillating material; predicate device uses a wired 

detector with CsI

• New device detector has worse DQE and MTF performance, likely due to scintillator material.

• Sponsor is asked to provide a reference device with equivalent/worse performance to predicate.

• Differences in connectivity of detectors to x-ray system can result in integration issues

• Does not introduce different questions of safety/effectiveness. 

Memo
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• Additional features added to the already-cleared software may influence diagnostic quality of produced 

images from system

AutoGrid

• AutoGrid software option is to enhance image contrast in general radiographic images of chest and 

abdomen images by reducing the effects of scattered radiation on the image, post-acquisition.

• New feature is not intended to replace any physical grid.

• Questions of safety/effectiveness are same for any x-ray system e.g. image quality at a reasonable dose.

Memo Characteristic New Device Predicate Device

Software platform

Software Ready Image 

v1.1 Ready Image v1.0

Features AutoGrid Not present

LDP Not present
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LDP

• LDP feature enhances image quality by using advanced noise reduction algorithm.

• Feature is intended to be used together with lower dose protocols , to allow low dose images 

with same diagnostic quality as images taken at full dose.

• Feature does not introduce new questions of safety/effectiveness.

Memo

Characteristic New Device Predicate Device

Software platform

Software Ready Image 

v1.1 Ready Image v1.0

Features AutoGrid Not present

LDP Not present
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Decision 5a

Are the 

methods 

acceptable?
42

Review Methods of 

Performance Testing

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Where 

To

Look

 EMC, electrical, mechanical, thermal and radiation safety - often covered by standards conformance 

 Sterilization and shelf life

 Biocompatibility 

 Software – verification and validation testing

 Performance testing – bench, clinical 

What 

To 

Do

 Focus on performance testing for new / modified components, especially:

 Detectors –

 MTF, DQE, NPS and other recommendations in SSXI guidance

 FDA wireless guidance

 Post processing software 

 For claims, make sure the sponsor provides performance testing to substantiate claims.

 Did the sponsor appropriately support their testing methodology with reference to appropriate FDA guidance, 

reference devices or secondary predicates, standards or literature 

 Note: Please contact FDA immediately upon discovery of quantitative dose & image quality improvement claims 

and clinical performance claims 

What 

To 

Document

 Each performance test provided and corresponding evaluated new / different characteristics

 Conclusion on whether all concerns on safety/effectiveness are adequately addressed by supplied performance 

testing.
43

Software

Electrical Safety, Electromagnetic Compatibility (EMC) and Radiation Safety

Cleaning, Disinfection and Sterilization

Biocompatibility

Nonclinical and Clinical Performance Testing

Look at 5 Types of

Performance Testing

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References

• Guidance for the Content of Premarket Submissions 

for Software Contained in Medical Devices

• General Principles of Software Validation; Final 

Guidance for Industry and FDA Staff

• Guidance for Industry, FDA Reviewers and 

Compliance on Off-The-Shelf Software Use in Medical 

Devices

States device is Moderate 

Level of Concern

Look at 5 Types of Performance Testing

Software

Electrical Safety, EMC, and Radiation Safety

Cleaning, Disinfection and Sterilization

Biocompatibility

Nonclinical and Clinical Performance Testing

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Software

• Level of Concern: moderate

• Documentation based on moderate level of concern

Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices

• Clarify and document whether software is actually changing

– If no new features, but new hardware components:

• focus on integration issues in V&V

– Modifications to existing software platforms- risk analysis and corresponding 

verification and validation

– If new: pick features that have lot of interaction with other software or 

hardware (e.g., AEC) and trace through SRS, SDS, V&V and risks

• Ensure and document validation of final, finished device

Hints 

& 

Tips

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Hazard – AAD-78 

Autogrid not applied to 

post acquisition images

• Potential Hazard/ Failure – Misdiagnosis

• Potential Cause of Hazard/ Failure - Wrong Post Image

• Potential Effect of Hazard/ Failure – Misdiagnosis / Examination delay / Re-exposure 

Mitigations – 3.19-AAD • Prompt user for Autogrid option On/Off prior to acquisition sequence

• User manual instructions on how to use Autogrid feature correctly.

Verification –

VDS.3.19.AAD

• Operate Autogrid only when ON AutoGrid option - PASSED

• The functional operation AutoGrid smoothly on / off - PASSED

• After setting the option On AutoGrid it should proceed smoothly perform Post-processing -

PASSED

• AutoGrid images should be obtained within 10 seconds after image acquisition – PASSED

Example of hazard for Auto Grid feature and verification/validation testing:

Sponsor provided full software documentation according to a moderate level of concern. 

Because the software is a modification of an existing FDA-cleared device, the review focused on 

• Risks analysis and corresponding V&V of new software features

• Integration of new hardware components wit software

Software Documentation Memo

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Cyber Security

Risk Management

Adequate Threat Model?: Yes 

Cybersecurity Vulnerabilities/Risks: Data is received via Wifi, LAN. There is a risk of the unauthorized access 

to data in the system. Such risk lead to patient privacy issues, and may be a threat to patient health and life. In addition, there is a USB port located 

on the workstation that may be susceptible to unauthorized access. 

Cybersecurity Controls: The system requires user authentication to grant access to trusted users, 

automatic time out, and activity logging. The user manual also recommends the use of the anti-virus SW to protect the system. 

Adequate Risk Management?: Yes 

Adequate Traceability?: Yes 

Plan for Continuing 

Support

Upgrade Plan: As defects are reported, they are managed according to the Defect Management Process. The software maintenance stream runs for 

two weeks between software update releases and is focused on fixing defects or adding targeted integration points. 

Sufficient Upgrade Plan?: Yes 

Plan for Malware -

Free Shipping

Shipping Plan: Approved software updates are allowed to be installed by authorized field service engineers. This is the only way to install new

software onto the system. The software update and installation mechanisms are not exposed and are not available to unauthenticated users 

Sufficient Shipping Plan?: Yes 

Labeling

Labeling: The user manual recommends the use of the anti virus SW, Manual Workflows, Back-up Systems and other risk mitigation measures and 

states that they are the responsibility of the customer to implement and manage for the protection of the system. 

Sufficient Labeling?: Yes 

Interoperability Number of Electronic Interfaces (EI): 1 USB

Electronic Interface is inactive?: No 

Electronic Interface is only meant for service?: Yes 

Memo

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States device conforms 

with IEC 60601-2-54

See FDA form 3654 to 

ensure all standards used 

in the submission are listed 

Look at 5 Types of Performance Testing

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Software

Electrical Safety, EMC, and Radiation Safety

Cleaning, Disinfection and Sterilization

Biocompatibility

Nonclinical and Clinical Performance Testing
49

Electrical Safety, EMC, 

and Radiation Safety

• Ensure testing has been 

performed on final 

finished device

• Document that the 

sponsor has conformed 

to the FDA recognized 

version of the standards

Conformance to particular standard (IEC 

60601-2-54) sufficiently addresses system 

safety, as this standard incorporates base 

safety standard (IEC 60601-1) and a 

number of collateral and reference 

standards that cover EMC (e.g., IEC 60601-

1-2), electrical, mechanical, thermal, and 

radiation safety.

Example of Documenting 

Conformance

Memo

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Sponsor should provide 

appropriate cleaning 

instructions

Reference

Reprocessing Medical Devices in Health 

Care Settings: Validation Methods and 

Labeling

Look at 5 Types of Performance Testing

Software

Electrical Safety, EMC, and Radiation Safety

Cleaning, Disinfection and Sterilization

Biocompatibility

Nonclinical and Clinical Performance Testing

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51

Cleaning, Disinfection,

Sterilization

• Ensure the sponsor provided appropriate cleaning 

instructions

– Recommendation of a cleaning agent 

Reviewer Recommendation

Cleaning, Sterilization, Shelf-Life and Reuse descriptions are acceptable.

Reprocessing, Sterilization and Shelf-Life

The device is non-sterile when used, and user manual includes cleaning instructions.

Memo

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Usually not applicable to 

X-ray systems

Reference Use of International Standard ISO10993, Biological Evaluation of Medical Devices 

Part 1: Evaluation and Testing

Look at 5 Types of Performance Testing

Software

Electrical Safety, EMC and Radiation Safety

Cleaning, Disinfection & Sterilization

Biocompatibility

Nonclinical and Clinical Performance Testing

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Biocompatibility

The sponsor proposes the use of a barrier (e.g., sheath or drape). As a result,

there are no patient-contacting components.

Biocompatibility

• Ensure there are no patient contacting components 

• State whether manual recommends use of “exam paper” or any separating 

material between patient and system components

Reviewer Recommendation

The Biocompatibility information is acceptable.

Memo

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Look at 5 Types of Performance Testing

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Determine what testing is necessary 

based on predicate & new/modified 

features

Reference Guidance for the Submission of 510(k)s for Solid State X-ray Imaging Devices

Questions to answer

• Are there standards or well-accepted test 

methods?

• What performance testing methods were 

used for predicate and 

secondary/reference devices?

• Are these methods appropriate for the 

new device?

• For different features, are there any 

additional tests needed for the new 

device?

Software

Electrical Safety, EMC, and Radiation Safety

Cleaning, Disinfection and Sterilization

Biocompatibility

Nonclinical and Clinical Performance Testing
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Decision 5b

Do the data 

demonstrate 

substantial 

equivalence?
56

Flow Chart: Decision Points 5b

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Where 

To 

Look

 EMC compatibility and electrical safety

 Sterilization and shelf life

 Biocompatibility 

 Software – V&V testing

 Performance testing – bench, clinical 

What 

To 

Do

 Identify all risk analysis methods used to assess impact of new / modified features.

 Based on risk analysis, summarize all V&V activities required including test and acceptance criteria applied 

 Focus and highlight testing and results for new / modified features e.g. software features that impact output 

image 

What 

To

Document

 Description of V&V activities and conclusion

 Brief description of bench testing (clinical if applicable) and discussion on how the results demonstrate 

substantial equivalence. 
57

Bench Testing

• Sponsor provided testing evaluating the system for its signal linearity, 

quantum-noise-limited range of operation, lag, spatial resolution in terms of 

the modulation transfer function (MTF), image noise in terms of the Wiener 

noise power spectrum (NPS), and dose efficiency in terms of the detective 

quantum efficiency (DQE) according to the “Guidance for the Submission of 

510(k)s for Solid State X-ray Imaging Devices”.

• Sponsor stated that the measurements were made in accordance with IEC 

62220-1, which describes a standardized method by which the MTF, NPS 

and DQE can be measured.

• Provided documentation per Wireless Guidance

Memo

D1 D2 D3 D4 D5a D5b
58

Bench Testing

MTF

• MTF curves provided in both -x and -y directions for the new and predicate devices.

• For the evaluated acquisition parameter, the new device’s detector had a lower MTF 

in both -x and -y directions indicative of lower spatial resolution than the predicate 

device.

• May be attributed to the difference in scintillator material.

• Does not demonstrate that the new device’s performance is as effective as the 

predicate, and is not acceptable.

This is a deficiency

Memo

D1 D2 D3 D4 D5a D5b
59

Bench Testing

DQE

• DQE for both new and predicate devices are shown in Figure 4.5 and the integrated DQEs, δ, 

are listed in Table 4.5 of Section 18. At 10 keV, the new device’s detector has both the highest 

resolution and largest area, although the predicate’s CsI has a slightly higher DQE at low 

frequencies.

• At higher energies, new device’s Gadox-based scintillator rapidly deteriorates due the 

reduced absorption, and the predicate’s CsI-based scintillators gets better.

• Predicate detector’s CsI detector has higher absorption efficiency, making it better when 

looking at the integrated DQE.

• Does not demonstrate substantial equivalence between the new and predicate devices. 

This is a deficiency.

Memo

D1 D2 D3 D4 D5a D5b
60

Bench Testing

AutoGrid Phantom Image Evaluation 

• Sponsor provided anthropomorphic phantom study for the AutoGrid (scatter correction) 

software feature.

• Includes range of anatomical regions and patient size (chest AP and abdomen supine for 

medium, large, extra-large and child patient size, with the PBU-60 Phantom).

• Board certified radiologist evaluated the images.

• Considered adequate for this software modification because there were no quantitative 

claims and no claims that the feature could be used to replace use of a real grid.

LDP

• Sponsor provided a clinical image evaluation report 

• Includes comparison of 30 chests images (PA & Lateral) with and without LDP

• Statement from a board-certified radiologist (CV attached in Attachment).

• Considered adequate for this software modification an associated quantitative 50% dose 

reduction claim.

Memo

D1 D2 D3 D4 D5a D5b
61

Substantial Equivalence Determination Yes No

1. Is the predicate device legally marketed? 

2. Do the devices have the same intended use? 

Please explain how the intended use of the new device is similar to or different from the predicate device: 

Both devices are intended for general projection radiographic images of human anatomy in all general-purpose diagnostic 

procedures. 

3. Do the devices have the same technological characteristics? 

Please describe the different technological characteristics: 

The new device utilizes a wireless digital detector with Gadox as scintillator material compared to the predicate's wired CsI

digital detector. In addition, the new device has a modified version of the existing image software used in the predicate. These

features include AutoGrid (virtual grid) to reduce x-ray scatter, and LDP (low dose protocol) to reduce patient dose up to 50% 

by noise reduction. 

4. Do the different technological characteristics of the devices raise different questions of 

safety and effectiveness? 

5a. Are the methods acceptable? 

5b. Do the data demonstrate equivalence and support the Indications for Use? 

Please explain how the data do or do not demonstrate substantial equivalence: 

The new device conforms to IEC 60601-2-54, which covers most safety related concerns. Sponsor provided adequate data 

according to SSXI, wireless, pediatric, cybersecurity and software guidances. Sponsor supported MTF and DQE performance 

through comparison to a reference device. AutoGrid and LDP features were further supported through an anthropomorphic 

phantom study reviewed by a board-certified radiologist. Sponsor removed quantitative image-quality improvement and dose 

reduction claims associated with these features.

Memo
62

Substantially Equivalent

Identify the new 

device and the 

predicate device 

Decision 1

Is the predicate 

device legally 

marketed?

Decision 2

Do the devices have 

the same intended 

use?

Decision 3

Do the devices

have the same 

technological 

characteristics?

Decision 5a

Are the methods 

acceptable?

Decision 5b

Do the data 

demonstrate 

substantial 

equivalence?

Decision 4

Do the different

technological characteristics

of the devices raise different

questions of safety and

effectiveness?

Final Decision 

SE

Yes No

Yes

No

Yes

Yes
63

510(k) Summary

• Ensure all administrative information is correct:

– 510(k) numbers, trade/proprietary names, classification 

name, regulation number, product code

• Performance data section described

• Information in 510(k) should reflect the cleared 

device 
64

Revisiting Keys to Success

• Thoroughly identify and compare existing and 

new/modified components of new device to 

predicate

• Use the 510(k) Decision-Making Flowchart

• Be familiar and use relevant resources and 

references
65

Acronyms 

• TPLC – Total Product Life Cycle

• MDR – Medical Device Reporting

• MAUDE – Manufacturer and User Facility Device Experience

• NSE – Not Substantially Equivalent

• QSUB – Q-Submission

• Rx - Prescription

• OTC – Over the counter

• MTF – Modulation Transfer Function

• NPS – Noise Power Spectrum

• DQE – Detector Quantum Efficiency 

• CADe – Computer Aided Detection
66

Resources

• The 510(k) Program: Evaluating Substantial Equivalence in Premarket Notifications [510(k)]

• IEC 60601-2-54 Medical electrical equipment – Part 2-54: Particular requirements for the basic safety and essential 

performance of X-ray equipment for radiography and radioscopy 

• IEC 62220-1-1 Medical electrical equipment – Characteristics of digital X-ray imaging devices – Part 1-1: Determination of the detective quantum efficiency - Detectors used in radiographic imaging

• Guidance for the Submission of 510(k)s for Solid State X-ray Imaging Devices

• MAUDE – Manufacturer and User Facility Device Experience

• Medical Device Recall Database

• 21 CFR 892.1680 - Stationary x-ray system

• 21 CFR 892. 1720 - Mobile x-ray system

• Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices

• Content of Premarket Submissions for Management of Cybersecurity in Medical Devices

• Pediatric Information for X-ray Imaging Device Premarket Notifications

• Radio Frequency Wireless Technology in Medical Devices

• Computer-Assisted Detection Devices Applied to Radiology Images and Radiology Device Data - Premarket Notification 

[510(k)] Submissions