The Hologic QDR Explorer is a fan beam X-Ray Bone Densitometer indicated for (1) the measurement of bone mineral content (BMC) and the estimation of bone mineral density (BMD), (2) comparison of measurements to reference databases, (3) the estimation of fracture risk, (4) body composition analysis, and (5) measurement of periprosthetic BMD

Device Description

AI/ML Overview

This submission (K033224) is a Special 510(k) for the Hologic QDR Explorer X-Ray Bone Densitometer. Special 510(k)s are used for modifications to a device already cleared by the FDA, where the modification does not affect the intended use or fundamental scientific technology of the device. Therefore, a comprehensive de-novo study proving the device meets acceptance criteria is typically not performed, as the substantial equivalence is largely based on the predicate device's performance.

Instead, the submission focuses on demonstrating that the modified device (QDR Explorer) is substantially equivalent to its predicate (QDR-3000 K943505 and Hologic Discovery Package for QDR X-Ray Bone Densitometers K023398) and continues to meet the safety and effectiveness standards established for bone densitometers. The information provided outlines changes in specifications rather than reporting specific performance metrics against acceptance criteria from a new clinical study.

Here's an analysis of the provided information in the context of your request:

1. Table of Acceptance Criteria and Reported Device Performance

The provided text does not include a table of acceptance criteria and reported device performance against those criteria as would be found in a primary clinical study for a new device. Instead, it presents a comparison table between the predicate device (QDR-3000) and the proposed device (QDR Explorer) to demonstrate substantial equivalence.

The "acceptance criteria" for a Special 510(k) often revolve around demonstrating that the modified device performs comparably to the predicate device and that the changes do not introduce new safety or effectiveness concerns. For this specific device, the "performance" aspects highlighted are primarily changes in hardware specifications.

Here's a reinterpretation of the provided table, focusing on the differences and implied acceptance of parity:

Feature/Criterion	Predicate Device (QDR-3000) Performance	Proposed Device (QDR Explorer) Performance	Implied Acceptance Criteria & Outcome
System Footprint	3.02m L x 1.50m W x 1.42m H +/- 25mm	Same	Acceptance: Maintained form factor of predicate. Outcome: Meets.
System Weight	320 kg (720 lb)	327 kg (729 lb)	Acceptance: Similar weight, not introducing significant structural or handling changes. Outcome: Meets (minor increase accepted).
System Power Requirements	Variety of regional specifications	Same	Acceptance: Maintained power safety and compatibility. Outcome: Meets.
X-Ray Tube	Switched pulse dual-energy x-ray tube	Same	Acceptance: Maintained safe and effective X-ray generation. Outcome: Meets.
Detector Array	64 multichannel CdWO4 detectors	54 multichannel CdWO4 detectors	Acceptance: New detector array provides equivalent image quality/measurement accuracy for intended use. (Implied, explicit criteria not provided, but reduction in channels suggests a design change that needed to be justified as not compromising performance). Outcome: Meets (accepted as substantially equivalent).
X-Ray Source-to-Image-Detector Distance	1070 mm	883.4 mm	Acceptance: Modified geometry does not negatively impact image quality, dose, or measurement accuracy. (Implied). Outcome: Meets (accepted as substantially equivalent).
X-Ray Source-to-Patient Distance	424 mm	Same	Acceptance: Maintained consistent patient exposure geometry. Outcome: Meets.
Collimation	1.0 mm slit	Same	Acceptance: Maintained intended X-ray beam shaping for image quality and dose. Outcome: Meets.
Leakage Radiation	Meets 21 CFR 1020.30(k)	Meets 21 CFR 1020.30(k)	Acceptance: Complies with federal radiation safety standards. Outcome: Meets.
Scatter Radiation	10μGy/hr at 1m (Nominal)	Same	Acceptance: Maintained safe scatter radiation levels. Outcome: Meets.
Scan Time	15 - 407 seconds	62 - 403 seconds	Acceptance: Scan times remain within a clinically acceptable range; variation is not considered a significant difference impacting safety or effectiveness. Outcome: Meets (slightly different range accepted).
Software Operating System	Hologic Eagle (Win 98)	Hologic Discovery (Win XP)	Acceptance: New software package (K023398) provides equivalent functionality, safety, and effectiveness. Outcome: Meets (cleared by prior 510(k) K023398).
PC Hardware Requirements	> 1.0 GHz processor, 256MB RAM etc.	> 1.5 GHz processor, 256MB RAM etc.	Acceptance: Updated hardware meets performance needs of new software, doesn't compromise functionality. Outcome: Meets (upgrade accepted).
Core Functionality (BMC, BMD, Fracture Risk, Reference DB, Body Comp, Periprosthetic BMD)	Standard / Optional (cleared by previous 510(k))	Same (cleared by previous 510(k)s)	Acceptance: The device performs its intended functions effectively, as established by prior clearances for these features. Outcome: Meets.

2. Sample Size for the Test Set and Data Provenance

This Special 510(k) primarily relies on the established performance of the predicate device (QDR-3000) and previous clearances for its software and additional functionalities (e.g., K023398 for Discovery software, K983028 for fracture risk, K963363 for reference databases, K961787 for body composition, K002711 for periprosthetic BMD).

There is no dedicated sample size for a "test set" reported for the QDR Explorer in this submission that would involve new clinical data collection. The submission emphasizes substantial equivalence documentation of specification changes, largely in hardware and software versions. If any testing was done to confirm the functionality of the new detector, source-to-detector distance, or new software running on new hardware, it would likely be in the form of engineering verification and validation tests, not a clinical trial with a "test set" in the traditional sense of evaluating diagnostic accuracy.

The data provenance for the predicate device's original clearance would have been specific to that submission (K943505). Similarly, the data for the cleared software (K023398) and other functionalities (K983028, K963363, K961787, K002711) would be tied to their respective 510(k) submissions. This document itself doesn't provide new clinical data.

3. Number of Experts and Qualifications for Ground Truth

Given that this is a Special 510(k) based on substantial equivalence to an already cleared predicate and the focus is on hardware/software updates, there is no mention of experts establishing a new ground truth for a test set. The fundamental "ground truth" for bone densitometry is typically established through clinical correlation studies comparing BMD measurements to, for example, fracture rates, or to other validated methods like quantitative computed tomography (QCT) or direct bone biopsy (though less common for routine densitometry validation). These would have been part of the predicate device's original clearance.

4. Adjudication Method for the Test Set

As there is no new clinical "test set" described in this submission, there is no adjudication method mentioned.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

Bone densitometers are typically quantitative measurement devices. Their performance is evaluated based on precision (reproducibility of measurements) and accuracy (how well measurements correlate with actual bone mineral content/density). They are not usually evaluated through MRMC studies that assess human reader interpretation of images, as is common for diagnostic imaging AI. Therefore, no MRMC study was performed or reported here, and thus no effect size of AI assistance on human readers.

6. Standalone Algorithm Performance Study

The Hologic QDR Explorer is a physical medical device (an X-ray bone densitometer), not an AI algorithm. Its performance is the direct output of the system (BMC, BMD values). Therefore, the concept of a "standalone algorithm only without human-in-the-loop performance" doesn't directly apply. The device is the "algorithm" in a sense, as it processes the X-ray data to produce the measurements. The "performance" is the accuracy and precision of those measurements, which would have been established for the predicate device.

7. Type of Ground Truth Used

The "ground truth" for bone densitometry, in general, relies on:

Clinical Outcomes Data: Correlation of BMD measurements with actual fracture incidence or risk.
Pathology/Histology: In some research contexts, direct measurement of bone mineral content from biopsy.
Expert Consensus/Reference Standards: Usage of anthropomorphic phantoms with known bone mineral densities, and comparisons to established reference populations for Z-scores and T-scores.

For this Special 510(k), the ground truth essentially lies in the established clinical utility and accuracy of the predicate device (QDR-3000) and the prior clearances for its functionalities and software. The QDR Explorer, through its substantial equivalence claim, implicitly leverages this existing ground truth rather than generating new primary ground truth data.

8. Sample Size for the Training Set

There is no "training set" mentioned in the context of this device. Bone densitometers are primarily physics-based measurement systems, not machine learning algorithms that require a training set in the typical sense. Data used for developing or validating reference databases (e.g., K963363) would involve large epidemiological studies, but this submission doesn't detail those.

9. How the Ground Truth for the Training Set Was Established

As there is no "training set" for an AI algorithm, this question is not applicable to the information provided for this device. The development of reference databases, if considered a form of "training data," would involve large-scale population studies where age, sex, ethnicity, and direct BMD measurements are collected to establish statistical norms. These methods would have been detailed in the original 510(k)s for those specific functionalities (e.g., K963363).

Summary

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K033224

Hologic, Inc. October 3, 2003 Hologic QDR Explorer X-Ray Bone Densitometer SPECIAL 510(k) Premarket Notification

Section E

510(k) Summary

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E. 510(k) Summary

E.1 Company Identification

Hologic, Inc. 35 Crosby Drive Bedford. MA 01730 781-999-7300

E.2 Contact Information

Daniel F. Phelan Senior Regulatory Affairs Specialist

E.3 Date of Submission

October 3, 2003

E.4 Device Identification

Proprietary Name Classification Name: Common/Usual Name Requlation Number: Product Code: Classification Classification Panel

Hologic QDR Explorer X-Ray Bone Densitometer Bone Densitometer Bone Densitometer 21 CFR 892.1170 90 KGI 11 Radiology

E.5 Predicate Device Information

K943505 Hologic QDR-3000 X-Ray Bone Densitometer
Hologic Discovery Package for QDR X-Ray Bone Densitometers K023398

E.6 Device Description and Intended Use

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Hologic, Inc.
October 3, 2003

Hologic QDR Explorer X-Ray Bone Densitometer SPECIAL 510(k) Premarket Notification

KT333222

E.7 Substantial Equivalence

	QDR-3000	QDR Explorer
510(k) Number	K943505
System Footprint	3.02m (119 in) L x 1.50m (59 in) W x1.42m (56 in) H +/- 25mm (1 in).	Same
System Weight	320 kg (720 lb)	327 kg (729 lb)
System Power Requirements	100V (23A), 120V (18A), and 230V(9A) models available	Same
X-Ray Tube	Switched pulse dual-energy x-ray tubeoperating at 100 kV and 140 kV. 2.5mA average at 25% duty cycle.Tungsten target	Same.
Detector Array	64 multichannel detector consisting ofCdWO4 scintillators coupled to silicondiodes	54 multichannel detector consisting ofCdWO4 scintillators coupled to silicondiodes
X-Ray Source-to-Image-DetectorDistance	1070 mm (42 in) +/- 8 mm (0.315 in)	883.4 mm (34.8 in) +/- 8 mm (0.315 in)
X-Ray Source-to-Patient Distance	424 mm (16.7 in) +/- 6 mm (0.236 in)	Same
Collimation	Aperture with 1.0 mm slit.	Same
Laser Positioning Device	Laser diode < 1mW cross hair withemergency mechanical shutter.	Same
Leakage Radiation	The QDR-3000 meets therequirements of 21 CFR 1020.30(k) forleakage from the x-ray source.	The QDR Explorer meets therequirements of 21 CFR 1020.30(k) forleakage from the x-ray source
Scatter Radiation	10μGy/hr at 1m from the examinationtable (Nominal)	Same
Scan Time	15 seconds - 407 seconds, dependingon scan mode	62 seconds - 403 seconds, dependingon scan mode
Scan Sites	Lumbar spine (L1, L2, L3, L4),Proximal femur (hip), Forearm (radiusand ulna), Whole body	Same
Software Operating System	Hologic Eagle Software Windows 98-Based Operating System (K992677)	Hologic Discovery Software PackageWindows XP-Based Operating System(K023398)
PC Hardware Requirements	> 1.0 GHz processor> 256 MB RAM> 20 GB hard disk3.5" 1.44 MB diskette drive17" monitor (CRT)120 MB SuperDisk driveCD-ROM drive16 MB video cardStandard keyboard and mouse	> 1.5 GHz processorSameSameSame17" monitor (CRT or LCD)CD/RW driveN/ASameSame
BMC Measurement	Standard	Same
BMD Measurement	Standard	Same
Fracture Risk Estimation (K983028)	Standard	Same
Reference Databases (K963363)	Standard	Same
Body Composition Analysis (K961787)	Optional	Same
Periprosthetic BMD Measurement(K002711)	Optional	Same

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Image /page/3/Picture/1 description: The image is a black and white logo for the Department of Health & Human Services - USA. The logo features a stylized image of an eagle with three lines forming its body and wings. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" are arranged in a circular pattern around the eagle.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

NOV - 5 2003

Mr. Daniel F. Phelan Senior Regulatory Affairs Specialist Hologic, Inc. 35 Crosby Drive BEDFORD MA 01730-1401

Re: K033224 Trade/Device Name: Hologic ODR X-Ray Bone Densitometer Regulation Number: 21 CFR 892.1170 Regulation Name: Bone densitometer Regulatory Class: II Product Code: 90 KGI Dated: October 3, 2003 Received: October 6, 2003

Dear Mr. Phelan:

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.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such 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); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050,

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This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Office of Compliance at one of the following numbers, based on the regulation number at the top of the letter:

8xx.1xxx	(301) 594-4591
876.2xxx, 3xxx, 4xxx, 5xxx	(301) 594-4616
884.2xxx, 3xxx, 4xxx, 5xxx, 6xxx	(301) 594-4616
892.2xxx, 3xxx, 4xxx, 5xxx	(301) 594-4654
Other	(301) 594-4692

Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97) you may obtain. Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers. International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.

Sincerely vours.

Nancy C. Brogdon

Nancy C. Brogdon Director, Division of Reproductive, Abdominal and Radiological Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

Page 2

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A.2 Indications for Use Statement

510(k) Number (if known): K033224

Device Name: Hologic QDR Explorer X-Ray Bone Densitometer

Indications for Use:

(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE OF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

V Prescription Use______________________________________________________________________________________________________________________________________________________________

Over-The-Counter-Use

(Per 21 CFR 801.109)

(Optional Format 1)

Nancy C Brogdon

(Division Sign-Division of Reproductive and Radiological Devic 510(k) Number

Regulation Number and Section

§ 892.1170 Bone densitometer.

(a)
Identification. A bone densitometer is a device intended for medical purposes to measure bone density and mineral content by x-ray or gamma ray transmission measurements through the bone and adjacent tissues. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II.