(214 days)
QDOSE® Multi-purpose Voxel Dosimetry is indicated for use to provide estimates of radiation absorbed dose to organs and tissues of the body from medically administered radiopharmaceuticals, and to calculate total-body effective dose. Radiation absorbed dose calculations are based on clinical measurements of radioactivity biodistributions and biokinetics. QDOSE® is intended for applications in clinical nuclear medicine, molecular radiotherapy, radiation safety evaluations, risk assessment, record-keeping, and regulatory compliance. QDOSE® is indicated for use by professionals (medical physicists, radiologists and oncologists including nuclear medicine physicians), radiologic imaging technologists, health physicists and radiation safety officers and administrators, students in training, and others having interest in ability to calculate internal radiation doses from medically administered radiopharmaceuticals.
QDOSE® is a software package for calculating internal radiation doses from clinically administered radiopharmaceuticals. Patient time-activity data may be imported to QDOSE® in DICOM files from nuclear medicine clinical imaging. Dosimetry performed within QDOSE® is based on the use of calculated S values, determined for patient-like phantoms using a Monte Carlo method. The S values provide the average absorbed dose to a target organ generated by a unit of activity in a source organ time-activity curves from quantitative nuclear medicine imaging data are integrated to yield an estimate of the number of radionuclide decays representing the area under a time-activity function, similarly to the mathematical process used by OLINDA/EXM. QDOSE® dose calculations are performed by multiplying a source organ timeactivity curve integral by the S value generated from Monte Carlo calculations. The product of the dose calculations is an output of radiation absorbed doses to specified target organs per unit administered activity.
The provided text describes the QDOSE® Multi-purpose Voxel Dosimetry device and its substantial equivalence to a predicate device (OLINDA/EXM v.2.0) for regulatory approval (K230221). It includes information on performance testing and comparison, but it does not explicitly state specific acceptance criteria in a quantitative manner (e.g., "Accuracy must be within X%"). Instead, it describes performance in terms of favorable comparison and small or insignificant differences relative to theoretical values and predicate/reference devices.
Therefore, the "acceptance criteria" are inferred from the demonstrated performance and the conclusion of substantial equivalence.
Here's an attempt to structure the information based on the provided text, acknowledging the limitations regarding explicit acceptance criteria:
Acceptance Criteria and Study Proving Device Performance: QDOSE® Multi-purpose Voxel Dosimetry
The acceptance criteria for the QDOSE® device are implicitly defined by its demonstrated ability to perform internal radiation dosimetry in a manner "similar" or "comparable" to established predicate and reference devices, and to produce results that are quantitatively close to theoretical values where applicable. The study aims to demonstrate substantial equivalence to the predicate device and other reference devices, indicating that the new device is as safe and effective.
1. Table of Acceptance Criteria (Inferred) and Reported Device Performance:
| Acceptance Criteria (Inferred from Performance Goals) | Reported Device Performance and Comparison |
|---|---|
| Accuracy of Time-Integrated Cumulated Activities: | |
| - Planar Workflow: Effective half-lives and calculated activities should compare favorably to theoretical values and between QDOSE® and Hermes Voxel Dosimetry. | Planar Workflow: Average deviation of measured effective half-lives was ~0.2% (between QDOSE® and Hermes Voxel Dosimetry). Average difference of calculated activities was ~1.3%. |
| - Hybrid Workflow: Cumulated activities should compare favorably to theoretical values. | Hybrid Workflow: Deviation of cumulated activities was ~0.3%. |
| - Volumetric Workflow: Cumulated activities should compare favorably to theoretical values. | Volumetric Workflow: Deviation of cumulated activities was ~0.04%. |
| Accuracy of Organ Absorbed Dose Calculations: | |
| - Mean relative difference for beta/gamma-emitting radionuclides (adult male/female) compared to OLINDA/EXM 2.0 (Note: Anatomical phantom differences acknowledged). | Pooled Beta/Gamma Emitters: Mean relative difference was 7% for adult male phantom and 8.8% for adult female phantom (QDOSE® IDAC-Dose 2.1 vs. OLINDA/EXM 2.0). These differences reflect known anatomical model variations. |
| - Mean relative difference for alpha-emitting radionuclides (adult male/female) compared to OLINDA/EXM 2.0. | Alpha Emitters: Mean relative difference was 10.7% for adult male phantom and 11.6% for adult female phantom (QDOSE® IDAC-Dose 2.1 vs. OLINDA/EXM 2.0). These differences reflect known anatomical model variations. |
| - Organ-specific relative differences compared to OLINDA/EXM 2.0 should be within acceptable ranges for clinical use. | Organ-Specific Differences: Varied from ~1% for kidneys, liver, spleen, and thyroid, to ~25% for red marrow. These differences are attributed to variations in assumed anatomical geometry, mass, shape, position, and tissue composition between the software packages. |
| - Agreement with spherical model calculations, compared to OLINDA/EXM. | Spherical Model: Agreement with less than 5% difference for absorbed dose values. |
| - Agreement with Voxel S method calculations, compared to OLINDA/EXM. | Voxel S Method: Mean difference relative to OLINDA/EXM of about 6%. |
| Intercomparison with other established dosimetry software: | Observable variability in reported doses should be generally small and within acceptable clinical ranges. For example, for organ walls with contents, within ±20%. |
| Nonclinical Intercomparison by Others: QDOSE® (IDAC-Dose 2.1) compared favorably with OLINDA 1 and 2, ICRP Publication 128, and MIRDcalc 1. Observed variability was generally small, and for organ walls with contents, all results were still within ±20% and within the standard error usually assumed for medical internal radiation dose estimates. | |
| Safety and Effectiveness: Differences from predicate should not raise new questions regarding safety and effectiveness. | The submission concludes that differences between QDOSE® and predicate/reference devices "do not raise new questions regarding safety and effectiveness of the device," and it is "as safe and effective as are its predicate devices." Minor differences in embedded methodology are considered normal and not critical because basic physics equations and nuclear data remain constant. User-related factors (training, calibration, ROI delineation) are acknowledged as main sources of small numerical differences. The device allows for patient-specific internal dosimetry based on fundamental science principles and internationally accepted methods. |
2. Sample Size Used for the Test Set and Data Provenance:
- Test Set Sample Size: The document refers to "phantom datasets" for the applicant's nonclinical testing. No specific number for the test set "sample size" in terms of unique phantom cases is provided. The tests involved calculating time-integrated cumulated activities across planar, hybrid, and volumetric workflows, and comparing organ absorbed doses for various radionuclides and phantoms (adult male/female).
- Data Provenance: The data for the nonclinical tests was generated from "phantom datasets." The document does not specify the country of origin of this data, but the company (Versant Medical Physics and Radiation Safety) is based in Kalamazoo, Michigan, USA, and the software developer (ABX-CRO) is from Dresden, Germany. The tests conducted by "others" refer to intercomparison studies published by groups like the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine and Medical Imaging. This suggests a mix of internal company data and external, possibly multi-center or widely accepted, phantom-based benchmark data. The studies are nonclinical, using phantom data, not patient data (retrospective or prospective).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:
- Number of Experts: Not explicitly stated. The "ground truth" for the nonclinical phantom tests appears to be established by comparison with theoretical values (for time-integrated activities) and established, validated software packages (OLINDA/EXM, ICRP Publication 128, MIRDcalc 1).
- Qualifications of Experts: The document emphasizes that dose calculations are based on "fundamental science principles and internationally accepted methods and phantom models" (Page 10). The internal dose calculational engine (IDAC-Dose 2.1) is used by the International Commission on Radiological Protection (ICRP) to generate dose estimates. This implies that the 'ground truth' or comparators are derived from well-established scientific communities and their endorsed methodologies rather than individual expert adjudication on a case-by-case basis.
4. Adjudication Method for the Test Set:
- Adjudication Method: Not applicable in the sense of human expert consensus for a clinical test set. The validation is primarily through comparison against theoretical values and results from established, previously validated software (OLINDA/EXM, ICRP Publication 128, MIRDcalc 1). Any "adjudication" is implicitly integrated within the established scientific and regulatory standards for dosimetry software validation.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:
- No, an MRMC comparative effectiveness study was not done. The studies described are nonclinical, using phantom data and software comparisons, not human readers interpreting medical images. The device is a dosimetry calculation software, not an AI for image interpretation or diagnosis.
6. If a Standalone (algorithm only without human-in-the-loop performance) was done:
- Yes, the primary evaluation is a standalone (algorithm only) performance assessment. The nonclinical tests evaluate the QDOSE® software's computational results (cumulated activities, absorbed doses) against theoretical values and outputs from other dosimetry software. While the software takes "clinical nuclear medicine diagnostic imaging" as input, the performance evaluation itself focuses on the accuracy of the algorithm's calculations, assuming correct data input. The statement "The software device includes all processing and calculation steps required for an internal dosimetry evaluation" (Page 4) and its comparison to other software further supports this.
7. The Type of Ground Truth Used:
- Theoretical Values / Computational Benchmarks: For time-integrated cumulated activities, QDOSE® results were compared against "theoretical values from calculations" (Page 13).
- Established Software Outputs: For absorbed dose calculations, the ground truth was predominantly the outputs from predicate and reference software devices (e.g., OLINDA/EXM 1.1 and 2.0, Hermes Voxel Dosimetry, ICRP Publication 128, MIRDcalc 1). The document acknowledges that "absolute ground truth in medical internal radiation dosimetry is not known" (Page 12, footnote 1), implying that the established software outputs serve as the best available benchmark.
8. The Sample Size for the Training Set:
- Not specified. The document focuses on performance testing (validation) and comparison to predicate devices. It does not mention a "training set" as would be typical for a machine learning model, suggesting that the software relies on established physics models and algorithms rather than statistical learning from a large dataset for its core functionality.
9. How the Ground Truth for the Training Set was Established:
- Not Applicable. Since a distinct "training set" in the context of a machine learning model is not described, the concept of establishing ground truth for it also does not apply. The "internal calculational algorithm" (IDAC-Dose2.1) is based on a "phantom-based approach" and incorporates "ICRP computational framework" and "MIRD schema" (Page 9, 6). This points to an engineering and physics-based development rather than a data-driven training approach.
§ 892.1100 Scintillation (gamma) camera.
(a)
Identification. A scintillation (gamma) camera is a device intended to image the distribution of radionuclides in the body by means of a photon radiation detector. This generic type of device may include signal analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component parts, and accessories.(b)
Classification. Class I (general controls).