(196 days)
InterSource125 implants are indicated for interstitial implantation of select localized tumors with low to moderate radiosensitivity. They are used either as primary treatment for tumors such as those of the head, lung, neck, pancreas, prostate, and unresectable tumors, or for residual disease after excision of the primary tumor. InterSource125 implants are indicated for use concurrent with or at the completion of other treatment modalities, such as external beam radiation therapy.
InterSource125 is a hermetically sealed radiotherapeutic source indicated for interstitial implantation. The radionuclide used in InterSource125 is Iodine-125 (I-125). InterSource125 is constructed by placing a platinum / iridium radiopaque marker and I-125 on the surface of a medical grade titanium inner tube. The device is sealed by sliding an outer tube, also medical grade titanium, over the inner tube and laser welding both ends. The resulting device has a hollow center with an inner diameter of 0.37 mm with all body tissue contacting surfaces made from medical grade titanium.
The InterSource125 device, an Iodine-125 seed for brachytherapy, demonstrated substantial equivalence to its predicate device, the Amersham/Medi+Physics Model 6711 Therapeutic Seed Source, rather than a direct performance study against acceptance criteria from a standalone test. The assessment of substantial equivalence was based on a comparison of key characteristics.
1. Table of Acceptance Criteria and Reported Device Performance
As this is a substantial equivalence submission, direct "acceptance criteria" as would be seen in a performance study with defined thresholds for metrics like sensitivity or specificity are not present. Instead, the "acceptance criteria" are implied by the similarity to the predicate device's characteristics. The "reported device performance" is the InterSource125's characteristics and its computed radiation distribution compared to the predicate's known characteristics and measured radiation distribution.
| Feature Description | Acceptance Criteria (Predicate Device) | Reported Device Performance (InterSource125) | Basis of Equivalence |
|---|---|---|---|
| Indications for Use | For interstitial treatment of tumors with specific characteristics (unresectable, localized, slow growth rate, low to moderate radiosensitivity). | Interstitial implantation of select localized tumors with low to moderate radiosensitivity. Used as primary treatment or for residual disease after excision. Used concurrently or after other modalities like external beam radiation therapy. | Indication statements were compared and found to be substantially equivalent in intent. |
| Physical Size | Length: 4.5 mm, Outside Diameter: 0.8 mm (Outer Tube) | Length: 4.5 mm, Outside Diameter: 0.8 mm (Outer Tube) | Identical dimensions. |
| Radiopaque Marker | Silver | Platinum / Iridium | Both devices incorporate a radiopaque marker. The material difference was assessed as not affecting equivalence. |
| Biocompatibility | Titanium (Outer Tube), Silver (Isotope Carrier) | Medical grade titanium (Outer Tube, Inner Tube, Isotope Carrier) | Both use known biocompatible materials. Titanium is specified for all body-tissue contacting surfaces in InterSource125. |
| Radioisotope | Iodine-125 | Iodine-125 | Identical radioisotope. |
| Half-life | 59.4 days | 59.4 days | Identical. |
| Principal Energy Levels | 27.2 keV, 27.5 keV, 31.0 keV, 35.5 keV | 27.2 keV, 27.5 keV, 31.0 keV, 35.5 keV | Identical. |
| Distribution of Isotope | Deposited onto the surface of the isotope carrier | Deposited onto the surface of the isotope carrier | Identical method. |
| Apparent Activity Levels | 0.18 to 5.99 mCi | 0.1 to 5.0 mCi | Comparable range, with InterSource125's range falling largely within or closely to the predicate's. |
| Residual Activity |
§ 892.5730 Radionuclide brachytherapy source.
(a)
Identification. A radionuclide brachytherapy source is a device that consists of a radionuclide which may be enclosed in a sealed container made of gold, titanium, stainless steel, or platinum and intended for medical purposes to be placed onto a body surface or into a body cavity or tissue as a source of nuclear radiation for therapy.(b)
Classification. Class II (special controls). A prostate seeding kit intended for use with a radionuclide brachytherapy source only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.