(114 days)
To estimate bone mineral content (BMC, grams) and bone mineral density (BMD, grams/cm').
The DTX-200 candidate device is a dual energy system, where the measured object, in this case the forearm, by the software, i s divided into two compartments, bone and soft-tissue. Having two energies, and two compartments (unknowns) it is possible to establish and solve two formulae with two unknowns. The X-Ray generator is driven at 55 kV , with a current of 300 yAmps. The beam is filtered with Tin (Sn), using the K-Edge of this material to enhance the separation of the low and the high energy. The average energy peaks are approximately 29 keV, and 46 keV respectively. A highly stable X-Ray output, together with a source collimation of 1 mm and a pixel resolution of 0.4mm X 0.4mm, yields images of very high quality. The detector is a sandwich construction, using solid state photodiodes consisting of two diodes with scintillation material. The two energies are separated by the sandwich construction. The X-ray beam meets the first scintillator, where predominantly the low energy is detected, and then it meets the second scintillator, where the rest of the energy is detected. The typical time to estimate bone mineral content and bone mineral density is approximately 4 minutes. The effective patient dose is estimated to be 0.1 micro Sievert per scan.
Here's a breakdown of the acceptance criteria and the studies performed for the DTX-200 Bone Densitometer, based on the provided 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
The provided text focuses on demonstrating substantial equivalence to predicate devices rather than explicit, numerical acceptance criteria for a novel device. The primary performance metrics evaluated are functional correlation and precision.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Functional Correlation: The DTX-200 candidate device should demonstrate a strong functional relationship and high correlation with the DTX-100 predicate device in estimating Bone Mineral Content (BMC) and Bone Mineral Density (BMD). | Functional Correlation Study: - Linear regression analysis was used to determine the degree of correlation between DTX-200 and DTX-100 for BMC and BMD measurements at the 8mm distal site and ultra distal site in the non-dominant forearm. - Conclusion: "The clinical study on eighty one (81) patients showed the DTX-200 candidate device and the DTX-100 predicate device are substantially equivalent in their ability estimate bone mineral content (BMC) and bone mineral density (BMD)." |
| Precision: The DTX-200 candidate device should be able to estimate bone mass with precision errors that allow for the detection of clinically meaningful differences between repeated bone scans in the same individual. | Precision Study: - Precision estimates were calculated as the coefficient of variation (CV) at a 95% confidence interval using log-transformed data for BMC and BMD measurements. - Conclusion: "The results of the clinical study on fifteen (15) individuals shows that the DTX-200 candidate device estimates bone mass with precision errors in an order that makes it possible to detect clinically meaningful differences between repeated bone scans in the same individual." |
| Comparability to Predicate Devices (General): Design, material, chemical composition, energy source, and other technological characteristics (e.g., precision, accuracy error) should be comparable to predicate devices. | Technological Characteristics Section: - States that these characteristics "are considered to be the same as the technological characteristics of the predicate devices." - Precision: "The precision of the devices [DTX-200, DTX-100, QDR-1000/W] is comparable." - Accuracy and precision error: "Accuracy and precision error of the DTX-200 candidate device is comparable to that of the DTX-100 predicate device and the QDR-1000/W predicate device." |
2. Sample Size Used for the Test Set and the Data Provenance
-
Functional Correlation Study:
- Sample Size: 81 individuals
- Data Provenance: Not explicitly stated whether retrospective or prospective, nor the country of origin. However, the study was sponsored by the device manufacturer (Osteometer Meditech A/S, Denmark), suggesting it was likely conducted in or around their location.
-
Precision Study:
- Sample Size: 15 individuals
- Data Provenance: Not explicitly stated whether retrospective or prospective, nor the country of origin. Similar to the correlation study, sponsored by the manufacturer.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts
The studies described in the 510(k) summary do not involve "experts" establishing a ground truth in the traditional sense of diagnostic interpretation. Instead, the ground truth is established by the measurements from the predicate device (DTX-100) for the functional correlation study, and the repeated measurements by the DTX-200 itself for the precision study. Therefore, no information on the number or qualifications of experts is provided for determining ground truth in these specific studies.
4. Adjudication Method for the Test Set
Not applicable. The studies are based on quantitative measurements from devices, not human interpretation requiring adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. The DTX-200 is a bone densitometer (device-only measurement), not an AI-assisted diagnostic tool that would involve human readers.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, the studies presented are effectively standalone evaluations of the device's performance. The DTX-200 bone densitometer operates as an algorithm-only device (though it lacks AI in the modern sense) without human intervention in the measurement process itself, beyond operating the machine. The studies evaluate the device's measurements directly.
7. The Type of Ground Truth Used
- Functional Correlation Study: The "ground truth" for the DTX-200's performance was the measurements obtained from the predicate device, the DTX-100 bone densitometer. The study aimed to show strong correlation with an already accepted device.
- Precision Study: The "ground truth" for evaluating precision was the mean of the multiple repeated measurements from the DTX-200 itself for each individual. The goal was to quantify the variability of the device's own measurements.
- For the referenced published literature (2A-2E), the ground truth varies depending on the study (e.g., in vivo bone mineral measurements, in vitro phantom measurements, cadaver studies, comparative measurements between different densitometry methods).
8. The Sample Size for the Training Set
The provided 510(k) summary describes performance evaluation studies (test sets) but does not mention any "training set." This is consistent with devices from this era, where machine learning/AI models requiring training data were not typically employed in this manner for medical device clearance. The DTX-200 uses established physics-based principles (DXA) rather than a data-driven model that would necessitate a training set.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as there is no mention of a training set for the DTX-200.
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510(k) Summary [This 510(k) summary is furnished in accordance with 21 CFR 807.92]
21 CFR 807.92(a):
21 CFR 807.92(a)(1):
- Submitter's name and address:
Osteometer Meditech A/S Glerupvej 2, DK-2160 Rodovre Denmark
-
Submitter's telephone number: 011 45 44 92 42 00
-
Contact person:
Ms. Anja Koue Official Correspondent Osteometer Meditech A/S Glerupvej 2, DK-2160 Rodovre Denmark
- Date this 510(k) summary was prepared: March 11, 1996
21 CFR 807.92(a)(2):
- 头 Trade/proprietary name of the device: DTX-200 Bone Densitometer
-
- Classification name: Bone densitometer
21 CFR 807.92(a)(3); Legally marketed device (predicate device) to which equivalence is claimed:
-
- Osteometer MediTech A/S model DTX-100 bone densitometer
-
- Hologic, Inc. model QDR-1000/W bone densitometer
21 CFR 807.92(a)(4); Description of the device that is the subject of this premarket notification:
The DTX-200 candidate device is a dual energy system, where the measured object, in this case the forearm, by the software, i s divided into two compartments, bone and soft-tissue. Having two energies, and two compartments (unknowns) it is possible to establish and solve two formulae with two unknowns.
The X-Ray generator is driven at 55 kV , with a current of 300
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.
510(k) Summary
[This 510(k) summary is furnished in accordance with 21 CFR 807.92]
yAmps. The beam is filtered with Tin (Sn), using the K-Edge of this material to enhance the separation of the low and the high energy. The average energy peaks are approximately 29 keV, and 46 keV respectively. A highly stable X-Ray output, together with a source collimation of 1 mm and a pixel resolution of 0.4mm X 0.4mm, yields images of very high quality.
The detector is a sandwich construction, using solid state photodiodes consisting of two diodes with scintillation material. The two energies are separated by the sandwich construction. The X-ray beam meets the first scintillator, where predominantly the low energy is detected, and then it meets the second scintillator, where the rest of the energy is detected.
The typical time to estimate bone mineral content and bone mineral density is approximately 4 minutes. The effective patient dose is estimated to be 0.1 micro Sievert per scan.
21 CFR 807.92(a)(5); Intended use:
The intended use of the DTX-200 candidate device is the same as the labeled intended use of the predicate devices to which equivalence is claimed; i.e., "To estimate bone mineral content (BMC, grams) and bone mineral density (BMD, grams/cm').
21 CFR 807.92(a)(6); Technological characteristics:
The design, material, chemical composition, energy source and other technological characteristics of the subject device are considered to be the same as the technological characteristics of the predicate devices. A summary of the technological characteristics of the subject device in comparison to those of the predicate devices follows:
米 X-ray transmission source:
Both the DTX-200 subject and the DTX-100 predicate bone densitometer devices consist of a computer, keyboard, monitor, printer, and scanner system using an X-ray transmission source. The DTX-200 candidate device uses dual X-ray photon absorptiometry (DXA), the DTX-100 predicate device uses single X-ray photon absorptiometry (SXA), and the ODR-1000 /W predicate device uses dual energy quantitative digital radiography to estimate bone mineral content (BMC) and bone mineral density (BMD).
* Soft-tissue equivalent material:
f
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510(k) Summary [This 510(k) summary is furnished in accordance with 21 CFR 807.92]
In contrast to the DTX-100 predicate device (that uses water as soft tissue equivalent material) and the QDR-1000/W predicate device (that uses a calibration wheel), the DTX-200 candidate device does not require the use of water as an soft tissue equivalent material. The precision of the devices is comparable.
Calibration: *
Both the DTX-200 candidate device and the DTX-100 predicate device use a line-by-line calibration system, ensuring good The QDR-1000/W predicate device self calibrates precision. using an automatic internal reference system.
Imaging technique, data acquisition, and quality control 大 phantom:
These characteristics are the same on the DTX-200 candidate device as the DTX-100 predicate device.
Source collimation: 头
The source collimation for both the DTX-200 candidate device and the DTX-100 predicate device is the l mm diameter. The source collimation for the QDR-1000/W predicate device is pencil beam, 0.09 inch diameter.
ま Reference location:
The reference location for both the DTX-200 candidate device and the DTX-100 predicate device is the 8 mm Ulna-Radius gap. The reference location for the QDR-1000/W predicate device is the ulnar styloid.
ま Accuracy and precision error:
Accuracy and precision error of the DTX-200 candidate device is comparable to that of the DTX-100 predicate device and the QDR-1000/W predicate device.
21 CFR 807.92(b);
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510(k) Summary
[This 510(k) summary is furnished in accordance with 21 CFR 807.92]
510(k) summaries for those premarket submissions in which a determination of substantial equivalence is also based on performance data shall also contain the following:
807.92(b)(1); 21 CFR Brief discussion of the nonclinical tests submitted, referenced, or relied on in this premarket notification submission:
There were no nonclinical tests submitted, referenced, or relied on in this submission.
21 CFR 807.92(b)(2); Brief discussion of the clinical tests submitted, referenced, or relied on in this premarket notification submission:
The results of seven (7) clinical tests were submitted, referenced, or relied on in this premarket submission. Two clinical tests were sponsored by the device manufacturer and five of the clinical studies were from published literature:
Two clinical tests sponsored by the device manufacturer; 1. a functional correlation study between the DTX-200 (A) candidate device and the DTX-100 predicate device and (B) a precision study of the DTX-200 candidate device.
A. Functional Correlation Study: Bone mineral content (BMC) and bone mineral density (BMD) were measured at the ထ mm distal site and the ultra distal site in the nondominant forearm of eighty one (81) individuals to determine the functional relationship and to evaluate the degree of correlation between the DTX-200 candidate device and the DTX-100 predicate device. Linear regression analysis was used to determine the degree of correlation.
B. Precision Study: Bone mineral content (BMC) and bone mineral density (BMD) were measured at the 8 mm distal site and the ultra distal site in the nondominant forearm of fifteen (15) individuals, five (5) times each, to estimate the precision error of the DTX-200 candidate device. The precision estimates were calculated as the coefficient of variation at a 95% confidence interval using log-transformed data.
- Five the clinical studies were of from published literature:
A. "Bone Changes Occurring Spontaneously and Caused by Oestrogen in Early Postmenopausal Women: A Local or
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510(k) Summary
[This 510(k) summary is furnished in accordance with 21 CFR 807.92]
Generalized Phenomenon?" Published in the British Medical Journal, 26th. April 1986, by Anders Gotfredsen, Lisbeth Nilas, Bente Juel Riis, Karsten Thomsen, and Claus Christiansen.
Abstract of this clinical study:
"Regional values of bone mineral content and bone mineral density were calculated from total body and 52 photon absorptiometry scans of early dual postmenopausal women treated with placebo. The six regions were head, arms, chest, spine, pelvis, and In addition, bone mineral density of the leas. measured photon lumbar spine was was by dual absorptiometry and bone mineral content of the forearm using single photon absorptiometry, using separate special purpose scanners. All regions were unchanged after one year of treatment with oestrogen, excluding the lumbar spine, for which values rose. Values for all regions except the spine fell significantly in the placebo lumbar The rates of loss ranged from 2% to 8%, group. with no significant differences among the regions."
B. "Single X-Ray Absorptiometry of the Forearm: Precision, Correlation, and Reference Data". Published Calcified Tissue International, in 1994, by T.L. in Kelly, G. Crane, and D.T. Baran.
Abstract of this clinical study:
"The performance of a single X-ray absorptiometry (SXA) device incorporating an X-ray tube as a photon source was evaluated with respect to precision in vivo and in vitro, scan time, image quality, and correlation with an existing dual energy X-ray absorptiometry (DXA) device. SXA precision in vivo, expressed as a coefficient of variation (CV), was 0.66% for bone mineral content (BMC) and 1.05% for bone mineral density (BMD). Precision in vitro, based on 78 measurements of a forearm was phantom over 195 days, 0.53%. Correlation with DXA at the 8 mm distal forearm site was high (r = 0.97 for BMC and r = 0.96 for A preliminary SXA reference data base BMD) . composed of 151 healthy Caucasian American women was developed to facilitate the interpretation of patient measurements. SXA scan time was 4 minutes
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510(k) Summary [This 510(k) summary is furnished in accordance with 21 CFR 807.92]
and delivered a radiation exposure of 1.68 mrem. image quality and spatial resolution were SXA superior to SPA and comparable to DXA."
"Impact of Soft Tissue on In Vivo Accuracy of Bone C. Mineral Measurements in the Spine, Hip, and Forearm: A Human Cadaver Study". Published the Journal of Bone and Mineral Research, Volume 10, Number 6, 1995, by Ole L. Svendsen, Christian Hassager, Vera Skodt, and Claus Christiansen.
Abstract of this clinical study:
"The impact of soft tissue in vivo based on bone mineral density (BMD) measurements of the spine and hip by dual energy X-ray absorptiometry and of the single photon absorptiometry was forearm by assessed by use of 14 human cadavers. The in vivo accuracy errors (SEE%) were: 3-5%, forearm anteroposterior spine 5.3%, lateral spine 10-12%, total , femoral greater trochanter, neck, and intertrochanteric, and Ward's triangle 3%, 6.5%, 8%, and 11-13%, respectively. Except from 6.78. the lateral spine and the greater trochanter, the slopes of the linear regressions of in vivo BMD against an in vitro BMD were not significantly different from 1(p > 0.05). The calculated random accuracy error of BMD measurements due to fat inhomogeneity was estimated to 3-4% for the anteroposterior spine and 9-14% for the lateral spine (from abdominal computed tomography in 26 healthy women)."
"Dual-Energy X-Ray Absorptiometry: A Precise Method D. of Measuring Bone Mineral Density in the Lumbar Spine". Published in The Journal of Nuclear Medicine, July 1990, by Marc A. Hansen, Christian Hassager, Kirsten Overgaard, Ulla Marslew, Bente J. Riis, and Claus Christiansen
Abstract of this clinical study:
"We compared two methods of measuring spinal bone mineral content and density (BMC/BMD): conventional dual-photon absorptiometry (DPA) and a more recent dual energy X-ray absorptiometry (DEXA). method, The clinical usefulness of both methods was compared in the measurement of BMC in the forearm. DEXA had a long term in vivo precision of 1% which
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510(k) Summary [This 510(k) summary is furnished in accordance with 21 CFR 807.92]
was significantly better than that of DPA. Changes in the distribution of fatty tissue influenced the accuracy of the two spinal methods in different Forearm BMC discriminated between the bone ways. mass of early and late postmenopausal women to the The variability in same degree as DPA and DEXA. the response to the estrogen treatment and placebo with DEXA and forearm BMC than with DPA."
"Patient Dose in Dual X-Ray Absorptiometry". E. Published in Osteoporosis International, (1994) 4:11-15, by M.K. Lewis, G.M. Blake, and I. Fogelman.
Abstract of this clinical study:
"Dual X-ray absorptiometry (DXA) provides convenient, non-invasive method of assessinq skeletal bone mineral which is widely used for clinical studies. This report describes a study to estimate dose of radiation [ICRP-60 (1990)] to a female patient from scans performed on three DXA scanners: the Hologic QDR-1000, QDR-1000/W and QDR-The scans modes studied were: total body; 2000. anteroposterior (AP) lumbar spine; lateral lumbar spine; proximal femur; distal forearm. An ion chamber and tissue-equivalent phantom were used to determine entrance surface dose and percentage depth-dose curves for each scan mode. Anatomical data from ICRP-23 (Reference Man) and a body section atlas were used to estimate the absorbed Effective dose to each organ in the scan fields. dose was estimated using the ICRP-60 tissue weighing factors and the fraction of each organ in the scan field.
21 CFR 807.92(b)(3; The conclusions drawn from the nonclinical and clinical tests that demonstrate that the subject device is as safe, as effective, and performs as well as or better than the predicate device:
Clinical studies sponsored by Osteometer MediTech A/S:
1A. Functional Correlation Study: The clinical study on eighty one (81) patients showed the DTX-200 candidate device and the DTX-100 predicate device are substantially equivalent in their ability estimate bone mineral content (BMC) and bone
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510(k) Summary
[This 510(k) summary is furnished in accordance with 21 CFR 807.92]
mineral density (BMD).
- Precision Study: The results of the clinical study on fifteen (15) individuals shows that the DTX-200 candidate device estimates bone mass with precision errors in an order that makes it possible to detect clinically meaningful differences between repeated bone scans in the same individual.
Clinical studies published in the literature:
2A. "Bone Changes Occurring Spontaneously and Caused by Oestrogen in Early Postmenopausal Women: A Local or Generalized Phenomenon?" This study concluded, "Loss of bone in early menopause is a generalized phenomenon, affecting all parts of the skeleton. Furthermore, oestrogen prophylaxis for loss of bone is effective in all parts of the skeleton. Finally, it is suggested that the measurement of bone mineral content in the forearm should be used for clinical follow up of bone changes, as this method is superior to others in the ratio of change to precision."
"Single X-Ray Absorptiometry of the Forearm: Precision, 28. Correlation, and Reference Data": This study concluded, "SXA image quality and spatial resolution were superior to SPA and comparable to DXA."
"Impact of Soft Tissue on In Vivo Accuracy of Bone 2C. Mineral Measurements in the Spine, Hip, and Forearm: A Human Cadaver Study": This study concluded, " Acceptable accuracy errors below 6-7% (of soft tissue in vivo) of BMD measurements were obtained in the anteroposterior spine, the forearm, and the neck, greater trochanter, and total proximal femur."
2D: "Dual-Energy X-Ray Absorptiometry: A Precise Method of Measuring Bone Mineral Density in the Lumbar Spine": This concluded, "that DEXA provides a fast and precise study measurement of spinal BMC/BMD. The accuracy remains to be evaluated for in vivo studies "
2E. "Patient Dose in Dual X-Ray Absorptiometry": This study concluded, "PDD (percentage depth dose) curves for the QDR-1000 and the QDR-1000/W part-body scans were found to be identical, with ESD (entrance skin dose) varying according to the speed of the scanning arm. The QDR-2000 pencil beam PDD curves were identical to those for the QDR-1000 and the QDR-1000/W with the ESD a factor of 1.6 higher due to the use of a lighter scanning table. The PDD curves for the QDR-2000 1-
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510(k) Summary [This 510(k) summary is furnished in accordance with 21 CFR 807.92]
2-min and 3-min fan beam spine and hip scans were min, identical with ESD measurements varying in proportion with scanning speed. As would be expected from the ESD and PDD curve data the effective doses for scans performed on the QDR-1000 and QDR-1000/W were identical while those for the QDR-2000 pencil beam mode were higher by a factor of 1.6."
... END OF 510(k) SUMMARY ....
§ 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.