(30 days)
The TomoTherapy HI-ART System is intended to be used as an integrated system for the planning and delivery of intensity modulated radiation therapy (IMRT) for the treatment of cancer. The HI-ART System provides precise delivery of radiation to tumors while minimizing the delivery of radiation to vital healthy tissue.
The HI-ART System's planning station is intended to be used by the physician/oncologist to prescribe a radiation therapy plan for a particular patient. The HI-ART System then calculates the treatment plan which the physician reviews and approves.
The HI-ART system's operator station and status console is then intended to be used by the therapist to select and implement the patient's treatment plan. The treatment process will begin by performing a Tomolmage™ (MVCT) scan (a CT using the onboard linear accelerator as the radiation source). This TomoImage (MVCT) will confirm that the patient's position is correct for the radiation therapy as well as assist in patient re-positioning when necessary. The Tomolmage (MVCT image) is not for diagnostic use.
When patient positioning is complete, the HI-ART System is then intended to be used by the therapist to treat the patient using the selected treatment plan. The HI-ART System delivers the radiation therapy, or stereotactic radiotherapy or radiosurgery, treatment in accordance with the physician approved plan using IMRT techniques delivered in a helical tomographic pattern.
The TomoTherapy HI-ART System is a radiation therapy system that integrates planning, dose calculation, megavoltage CT scanning, and helical radiation therapy treatment capabilities into a single comprehensive IMRT system.
The HI-ART System's planning station is used by the physician to prescribe and enter the radiation therapy plan. The patient's diagnostic CT image is imported via a DICOM protocol from another diagnostic CT device. The regions of interest, regions to avoid, and other prescribing information are entered in a manner that is similar to other commercially available planning systems.
The HI-ART System utilizes a 6 MV linear accelerator as the radiation source. The linear accelerator along with the primary collimator, multi-leaf collimator (MLC), detector, various control devices and power supplies are mounted on a rotating gantry. much like a CT gantry. During treatment or imaging, the patient is positioned on the couch support, and the couch moves axially through the bore of the gantry, and the radiation is delivered in a helical pattern.
The primary collimator and the MLC control the beam dimensions during radiation delivery so that the range of collimated beam size can vary from 0 to 400 mm wide by 5 to 50 mm at the isocenter. The MLC is constructed of 64 tungsten leaves that open and close as determined by the radiation therapy plan. The intensity of the radiation beam is proportional to the length of time that a particular leaf is open. The opening and closing of various leaves as the radiation is delivered in this helical pattern allows for an IMRT plan to be delivered with precise control. The result is a highly conformal dose to the region of interest with low doses to surrounding healthy tissue.
Because the HI-ART System is operating in a helical mode similar to CT systems, it inherently has the ability to obtain a CT image. The system utilizes the linear accelerator to obtain a megavoltage (MVCT) scan of the region of interest prior to the delivery of radiation therapy. This MVCT image is then used to ascertain that the patient is correctly positioned prior to treatment. The radiation dose to the patient from an MVCT scan is comparable to diagnostic CT or portal imaging.
Here's an analysis of the provided text regarding the acceptance criteria and study for the TomoTherapy HI-ART System (modified).
It's important to note that the provided documents are a 510(k) summary and the FDA's clearance letter. These documents primarily focus on demonstrating substantial equivalence to a predicate device and safety and effectiveness from a regulatory perspective. They generally do not contain detailed clinical study reports with specific acceptance criteria tables, sample sizes for test sets with ground truth, multi-reader multi-case studies, or detailed training set information as would be found in a full efficacy trial report.
Based on the provided text, the device's performance is demonstrated through its design and compliance with safety standards, and by showing substantial equivalence to a previously cleared device. There isn't a "study that proves the device meets the acceptance criteria" in the traditional sense of a clinical performance study with statistical endpoints outlined in the provided documents. Instead, the "acceptance criteria" are implied by the device's intended use and its compliance with relevant safety standards and technical specifications.
1. Table of Acceptance Criteria and Reported Device Performance
As mentioned, explicit quantitative acceptance criteria with reported performance metrics in a clinical study format are not present in these regulatory documents. The "acceptance criteria" are implied to be adherence to the specifications of an IMRT system for cancer treatment, safety, and functionality as described.
| Acceptance Criteria (Implied) | Reported Device Performance (from summary) |
|---|---|
| Integrated Functionality: System effectively integrates planning, dose calculation, MVCT scanning, and helical radiation therapy. | "The TomoTherapy HI-ART System is a radiation therapy system that integrates planning, dose calculation, megavoltage CT scanning, and helical radiation therapy treatment capabilities into a single comprehensive IMRT system." |
| Precision of Radiation Delivery: Delivers radiation precisely to tumors while minimizing delivery to healthy tissue. | "The HI-ART System provides precise delivery of radiation to tumors or other targeted tissues while minimizing the delivery of radiation to vital healthy tissue." |
| IMRT Capability: Capable of delivering Intensity Modulated Radiation Therapy (IMRT). | "The HI-ART System delivers the radiation therapy... using IMRT techniques delivered in a helical tomographic pattern." |
| Treatment Planning: Planning station allows physicians to prescribe and calculate treatment plans. | "The HI-ART System's planning station is intended to be used by the physician/oncologist to prescribe a radiation therapy plan... The HI-ART System then calculates the treatment plan which the physician reviews and approves." |
| Patient Positioning/Verification: MVCT scan confirms patient position and assists in repositioning. | "This TomoImage (MVCT) will confirm that the patient's position is correct for the radiation therapy as well as assist in patient re-positioning when necessary." |
| Safety: Device operates safely, avoiding injury to patients/operators. | "The HI-ART System has several characteristics that promote its safety - no beam blocks are used that can fall off onto the patient; the rotating gantry is covered so that the patient cannot contact moving gantry parts; the linear accelerator operates in photon mode only so inadvertent electron exposure is virtually eliminated; MVCT allows for reliable patient positioning." "The HI-ART System is designed to comply with relevant sections of the IEC 60601-1, IEC 60601-2-1, IEC 60601-1-2, IEC 60601-1-4 safety standards." |
| Mechanical/Beam Control: MLC controls beam dimensions and intensity. | "The primary collimator and the MLC control the beam dimensions... The MLC is constructed of 64 tungsten leaves... The opening and closing of various leaves as the radiation is delivered in this helical pattern allows for an IMRT plan to be delivered with precise control." |
| Dose from MVCT: MVCT radiation dose is comparable to diagnostic CT or portal imaging. | "The radiation dose to the patient from an MVCT scan is comparable to diagnostic CT or portal imaging." |
2. Sample Size Used for the Test Set and Data Provenance
The provided documents do not describe a specific test set or clinical study with patient data (like images or clinical outcomes) used to prove performance in the way a diagnostic AI device would. The "test" for this device appears to be its engineering specifications, functional testing, and comparison to a predicate device. Therefore, information on sample size, country of origin, or retrospective/prospective nature of a clinical test set is not present.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
Since there is no described clinical "test set" in the provided documents used to assess performance against a ground truth, this information is not available. The "ground truth" for a radiation therapy system is typically its ability to accurately deliver a planned dose to a target, which is assessed through physics measurements and phantom studies, rather than expert interpretation of images. The physician/oncologist reviews and approves the treatment plan, but this isn't a "ground truth" establishment for a device performance test in the diagnostic sense.
4. Adjudication Method (e.g., 2+1, 3+1, none) for the Test Set
Not applicable, as no clinical test set requiring expert adjudication is described in these documents.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, and the effect size of how much human readers improve with AI vs without AI assistance
Not applicable. The TomoTherapy HI-ART System is a sophisticated radiation delivery system, not an AI-based diagnostic or assistive reading tool. Its purpose is to physically deliver radiation therapy, and while it has a "planning station" that "calculates the treatment plan," this is not presented as an AI assistance tool for human readers (e.g., radiologists, oncologists) in the typical MRMC study context. Thus, there is no mention of such a study or effect size.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
This question typically refers to AI algorithms for diagnosis or analysis. The TomoTherapy HI-ART System is a physical medical device for treatment delivery. While parts of it involve calculation (treatment planning, dose calculation), its overall operation is described as intended for use by physicians and therapists, who ultimately review and approve plans and implement treatment. No "standalone algorithm-only performance" is described in the context of replacing human decision-making or interpretation.
7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)
As discussed, a clinical "ground truth" in the diagnostic sense (like pathology for cancer detection) is not applicable here. The "ground truth" for a radiation therapy delivery system primarily revolves around:
- Physics measurements: Verification that the system delivers the prescribed radiation dose distribution accurately to a phantom.
- Engineering specifications: The device performs according to its design parameters.
- Safety standards: Compliance with international safety standards (e.g., IEC 60601 series).
The documents confirm compliance with safety standards and describe the physical mechanisms (MLC, helical delivery) that enable precise dose delivery, implying that the "ground truth" is that the system adheres to these technical and safety specifications.
8. The Sample Size for the Training Set
Not applicable in the context of these documents. This device is not an AI algorithm trained on a dataset of cases in the traditional sense. It is a physical treatment delivery system. The "training" would refer to the engineering and physics design, calibration, and testing of the components, not a machine learning training set.
9. How the Ground Truth for the Training Set Was Established
Not applicable, for the reasons mentioned in point 8.
§ 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.