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The RSVP Half Sphere Phantom™ is designed for verification of therapy dose delivery in radiation therapy machines, specifically the Leksell™ Gamma Knife sterotactic radiosurgery system. The phantom can also be used for periodic quality assurance evaluations and acceptance testing, and to perform reevaluations after equipment or software upgrades. The phantom works in conjunction with commercially available ion chambers, which are not manufactured by the Phantom Laboratory.

The RSVP Half Sphere PhantomTM was developed to provide localization and dose verification for radiation therapy machines, specifically the LeksellTM Gamma Knife stereotactic radiosurgery system. The phantom's design provides full simulation of the localization and irradiation sequences. The hemi-spherical shape is formed from a urethane material and filled with water to simulate the radiation absorption and scatter of human soft tissue.

Based on the provided 510(k) summary, here's an analysis of the acceptance criteria and the study conducted for the RSVP Half Sphere PhantomTM:

1. Table of Acceptance Criteria and Reported Device Performance

The 510(k) summary does not explicitly define specific numerical acceptance criteria for performance metrics like accuracy, precision, or reproducibility. Instead, it relies on the device's design, manufacturing controls, and a scientific paper to demonstrate substantial equivalence and fitness for intended use.

However, based on the narrative, the implicit acceptance criteria relate to:

• Ability to simulate radiation absorption and scatter of human soft tissue: Achieved through the urethane material and water-filled design.
• Suitability for localization and dose verification in radiation therapy machines (specifically Leksell Gamma Knife): Demonstrated by comparison to the predicate device and the referenced study.
• Ease of position reproducibility for consistency monitoring: A stated advantage of the geometric shape.
• Manufacturing quality and calibration traceability: Ensured by adherence to ISO 9001:2000 and NIST traceability.

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size: The document does not specify a distinct "test set" in the context of clinical data for algorithmic performance. The validation relies on measurements taken during prototype development and the conclusions drawn from the referenced scientific paper. The number of measurements and pressure leak tests conducted during prototype creation is described as "numerous," but a specific numerical sample size is not provided.
• Data Provenance: The directly referenced study, "Calibration of the Gamma Knife using a new phantom following the AAPM TG51 and TG21 protocols" by R. E. Drzymala and R. C. Wood, would presumably be from a research setting, likely academic or institutional. The document does not specify the country of origin of this research or whether it was retrospective or prospective. The internal testing during prototype creation by The Phantom Laboratory would be prospective.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

This information is not provided as the device is a physical phantom for calibration and quality assurance, not a diagnostic or AI-driven interpretative device. Therefore, clinical "ground truth" established by experts in the typical sense (e.g., radiologists interpreting images) is not applicable or discussed for this type of device. The "ground truth" for a phantom would be its physical properties and performance against established dosimetry protocols, which are typically verified by medical physicists or engineers. The referenced paper's authors (R.E. Drzymala and R.C. Wood) are presumably experts in medical physics or a related field, given the subject matter (AAPM TG51 and TG21 protocols).

4. Adjudication Method for the Test Set

This information is not applicable as the device is a physical phantom for calibration, not a device requiring human interpretation or consensus for its "ground truth" in the way a diagnostic AI would.

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

No. A MRMC comparative effectiveness study is not relevant here. This device is a passive phantom used for calibrating and verifying radiation therapy machines, not an AI for image analysis or diagnosis that would assist human readers.

6. Standalone (Algorithm Only) Performance Study

No. This device is a physical phantom, not an algorithm. Therefore, "standalone" algorithmic performance is not applicable. Its "performance" is based on its physical properties and how accurately it facilitates dosimetry measurements when used with an ion chamber (which is a separate, commercially available product).

7. Type of Ground Truth Used

The "ground truth" implicitly used for the phantom's validation is based on:

• Physical principles and dosimetry protocols: Specifically, the AAPM TG51 and TG21 protocols mentioned in the referenced paper.
• Traceability to national standards: "Measurement equipment used was calibrated with traceability to NIST."
• Comparison to predicate device: Functional equivalence to the RSVP PhantomTM.
• Material properties: Selection of urethane and water to mimic human soft tissue radiation absorption and scatter.

8. Sample Size for the Training Set

Not Applicable. This device is a physical phantom and does not involve AI or machine learning that would require a "training set."

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

Not Applicable. As there is no training set, this question is not relevant.

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The RSVP Phantom™ Pelvis is designed for use in a variety of radiation therapy applications including, final quality verification of therapy dose delivery and for comparing the delivered dose profiles for different treatment plans. It is also used for periodic quality assurance evaluations and acceptance testing and to perform reevaluations after equipment or software upgrades.

The RSVP Phantom™ Pelvis provides isodose distribution and verification information for both conventional and intensity modulated radiation therapy machines. The life-size pelvic shape is formed from CAB material and filled with water to simulate the radiation absorption and scatter of human soft tissue.

Here's an analysis of the provided 510(k) summary for the RSVP Phantom™ Pelvis, focusing on acceptance criteria and supporting studies:

Acceptance Criteria and Device Performance for RSVP Phantom™ Pelvis

Based on the provided document, the RSVP Phantom™ Pelvis is a medical device phantom used for quality assurance in radiation therapy. Its primary function is to simulate human tissue for dose verification.

1. Table of Acceptance Criteria and Reported Device Performance:

Study Details:

The primary study mentioned is a comparative verification study against a predicate device.

2. Sample Size Used for the Test Set and Data Provenance:

• Sample Size: Not explicitly stated as a numerical value in terms of "cases" or "test samples." The document refers to "numerous measurements and pressure leak tests" for prototypes and "additional radiation measurements" conducted by the physicist. This suggests a series of experiments and tests rather than a single fixed "test set."
• Data Provenance: The testing was conducted during the device's development process and by a U.S. academic institution (Vanderbilt University). The nature of the measurements suggests prospective experimental data rather than retrospective clinical data.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:

• Number of Experts: One expert is explicitly named: "Physicist Charles W. Coffey, II, Ph.D. of Vanderbilt University."
• Qualifications of Experts: Ph.D. holder and a physicist at Vanderbilt University. While "physicist" is mentioned, his specific specialization (e.g., medical physicist, radiation physicist) is not detailed, but is implied by the context of radiation therapy measurements.

4. Adjudication Method for the Test Set:

• Adjudication Method: Not applicable or not explicitly detailed. The verification work appears to have been performed by a single expert (Dr. Coffey) comparing the new device against the predicate device's known functions and performance standards. There is no mention of multiple reviewers adjudicating discrepancies.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size:

• MRMC Study: No, an MRMC comparative effectiveness study was not done. This device is a phantom for calibrating and verifying radiation therapy machines, not an imaging or diagnostic device requiring human interpretation of medical images. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not relevant.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done:

• Standalone Performance: This concept is not directly applicable to a physical phantom. The phantom itself is a tool. Its "performance" is its ability to accurately simulate tissue properties for radiation dose measurements. The verification measurements performed by Dr. Coffey would be considered the assessment of the phantom's standalone performance in its intended function. There is no "algorithm" in the typical sense for this device.

7. The Type of Ground Truth Used:

• Ground Truth: The ground truth for evaluating the RSVP Phantom™ Pelvis was primarily based on:
  • Benchmarking against a legally marketed predicate device (K954634): The predicate device's established performance and "functions" served as a "gold standard" for functional equivalence.
  • "Actual patient absorbed dosages" simulation: The phantom is designed to mimic these, suggesting general physical principles and known dosimetric properties as part of the ground truth.
  • Calibrated measurements with traceability to NIST: This ensures the accuracy and reliability of the measurement equipment used during testing.

8. The Sample Size for the Training Set:

• Training Set Sample Size: Not applicable. This device does not use machine learning or AI that would require a "training set." It is a physical phantom.

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

• Ground Truth for Training Set: Not applicable, as there is no training set for this device.

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