(277 days)
The intended use of FOCUS RTP System is to provide radiation treatment planning capability, for both external beam and brachytherapy sources, to satisfy the prescription of a Radiation Oncologist. The resultant treatment plan is to be evaluated, modified as necessary, approved and delivered by qualified medical personnel. Operation of the system is identical to FOCUS systems cleared under previous Premarket Notifications with the exception the user can now select a third type of external beam particle for therapy (protons) in addition to the earlier two particles (electrons and photons)..
The FOCUS Radiation Treatment Planning System accepts a) patient diagnostic imaging data from CT and MR scans, or from films, and b) "source" dosimetry data, typically from a linear accelerator. The system then permits the user to display and define (contour) a) the target volume to be treated and b) critical structures which must not receive above a certain level of radiation, on these diagnostic images. Based on the prescribed dose, the user, typically a Dosimetrist or Medical Physicist, can then create multiple treatment scenarios involving the type, number, position(s) and energy of radiation beams and the use of treatment aids between the source of radiation and the patient (wedges, blocks, ports, etc.). The FOCUS system then produces a display of radiation dose distribution within the patient, indicating not only doses to the target volume but to surrounding tissue and structures. The "best" plan satisfying the prescription is then selected, one which maximizes dose to the target volume while minimizing dose to surrounding healthy volume. The parameters of the plan are output in hard-copy format for later reference and for placement in the patient file. Previously, for situations where external beam therapy was to be used, either Electron and/or Photon radiation beams could be selected.. These were delivered by a linear accelerator whose output characteristics are input to the treatment planning system prior to beginning planning. This Premarket Notification addresses the addition of a third type of radiation beam -Proton. The algorithm for calculating dose was provided by the Massachusetts General Hospital (MGH), based on their years of experience at the Harvard Cyclotron Lab. In addition to providing the algorithm, MGH also worked with CMS in its implementation. Software developers at MGH were trained on the CMS software development process to permit them to create code directly for use in FOCUS. As the final step, MGH provided the verification testing to assure the algorithm had been implemented correctly, measuring calculated dose against measures. A FOCUS RTP System with proton planning capability is now in clinical use at the Northeast Proton Therapy Center.
The provided text describes the K020027 FOCUS Radiation Treatment Planning System with Proton Planning Capability. It details the device's function, its new proton planning feature, and the non-clinical testing performed.
Here's an analysis of the acceptance criteria and study that proves the device meets them, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Accurate calculation of dose for proton treatment plans | "Algorithm test cases were written and executed to assure the system is calculating dose correctly for proton treatment plans." "The results of testing on the Proton Algorithm feature can be found in the Validation of the CMS Proton Treatment Planning System for Treatments In Large Field Beam Line at the Harvard Cyclotron Laboratory (HCL) authored by Skip Rosenthal of MGH. This document is included in Tab 15 of this 510(k)." The algorithm was provided by Massachusetts General Hospital (MGH) based on their significant experience (years) at the Harvard Cyclotron Lab (HCL). MGH also worked with CMS on its implementation and provided verification testing to ensure correct algorithm implementation, measuring calculated dose against measured values. |
| Substantial equivalence to predicate devices | The FDA determined the device is "substantially equivalent" to legally marketed predicate devices (Varian ProtonVision K000922 & K002312 and existing FOCUS RTP System versions cleared under K915691, K973936, and K002147). |
| Safety and effectiveness for intended use | The FDA's substantial equivalence determination implies it meets safety and effectiveness for its intended use, which is to provide radiation treatment planning capability for cancer patients, including proton external beam therapy. |
| Correct implementation of MGH-provided algorithm | "MGH provided the verification testing to assure the algorithm had been implemented correctly, measuring calculated dose against measures." |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: Not explicitly stated in terms of a specific number of cases or plans. The text refers to "Algorithm test cases" without detailing their quantity.
- Data Provenance: The testing was a "non-clinical" study. The algorithm was developed based on "years of experience at the Harvard Cyclotron Lab" at Massachusetts General Hospital (MGH). The verification testing involved measuring "calculated dose against measures," implying an experimental setup or phantom measurements rather than patient data. The study, "Validation of the CMS Proton Treatment Planning System for Treatments In Large Field Beam Line at the Harvard Cyclotron Laboratory (HCL)," suggests a laboratory-based, prospective evaluation of the algorithm's performance against physical measurements or highly controlled simulated scenarios.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- Number of Experts: Not explicitly stated. However, the algorithm itself was provided by the Massachusetts General Hospital (MGH), implying the expertise of their staff at the Harvard Cyclotron Lab (HCL). MGH also performed the verification testing.
- Qualifications of Experts: The text states the algorithm was based on "years of experience at the Harvard Cyclotron Lab." This implies the involvement of highly experienced medical physicists and other specialists familiar with proton therapy dose calculation. "Skip Rosenthal of MGH" authored the validation document, indicating his expertise in this area.
4. Adjudication Method for the Test Set
- Adjudication Method: Not applicable or not described. The validation appears to be a direct comparison of calculated dose values to measured dose values, rather than an expert consensus process.
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
- MRMC Study: No, an MRMC comparative effectiveness study was not done. The device is a radiation treatment planning system algorithm, not a diagnostic AI intended to assist human readers in interpreting images or making a diagnosis. Its function is to calculate dose distributions based on user input for treatment planning. The study focused on the accuracy of the dose calculation algorithm itself.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
- Standalone Performance Study: Yes, in essence, the "non-clinical testing" described is a standalone performance study. The "Algorithm test cases were written and executed to assure the system is calculating dose correctly for proton treatment plans." This focused solely on the algorithm's output (calculated dose) compared to a reference (measured dose), without evaluating user interaction or clinical outcomes in humans. The current device is meant to be used by "Dosimetrist or Medical Physicist" where they would evaluate, modify and approve the plans. However, the specific testing described in the summary is of the algorithm's accuracy in isolation.
7. The Type of Ground Truth Used
- Type of Ground Truth: The ground truth used was measured dose values. The text explicitly states "measuring calculated dose against measures" in the verification testing. This indicates that the algorithm's computed dose distributions were compared against physical measurements obtained from a phantom or experimental setup at the Harvard Cyclotron Laboratory.
8. The Sample Size for the Training Set
- Sample Size for Training Set: Not explicitly stated. The algorithm itself was provided by MGH, based on their "years of experience at the Harvard Cyclotron Lab." This implies that it was developed and implicitly "trained" or refined over a long period from extensive data and knowledge accumulated at HCL, but there's no defined "training set" in the context of supervised machine learning with a specific sample size.
9. How the Ground Truth for the Training Set Was Established
- Ground Truth for Training Set: The ground truth for the underlying algorithm's development (or its "training" in a broader sense) was established through extensive experience and data collection at the Harvard Cyclotron Lab (HCL) over many years. This would likely involve:
- Clinical experience and outcomes: Understanding how protons interact with tissue and the effects of different dose distributions.
- Physics measurements: Extensive experimental data on proton beam characteristics, interactions, and dose deposition in phantoms and biological samples.
- Computational modeling and simulations: Development and validation of physics models used in dose calculation.
The algorithm provided by MGH represents the culmination of this accumulated knowledge and empirical validation.
§ 892.5050 Medical charged-particle radiation therapy system.
(a)
Identification. A medical charged-particle radiation therapy system is a device that produces by acceleration high energy charged particles (e.g., electrons and protons) intended for use in radiation therapy. This generic type of device may include signal analysis and display equipment, patient and equipment supports, treatment planning computer programs, component parts, and accessories.(b)
Classification. Class II. When intended for use as a quality control system, the film dosimetry system (film scanning system) included as an accessory to the device described in paragraph (a) of this section, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.