For Radiation Oncology

Y-90 beta radiation characteristics

The LV Y-90 Disc contains high-purity yttrium-90, a pure beta emitter with a maximum beta energy of 2.28 MeV and a half-life of 64.0 hours. Y-90 beta radiation penetrates only millimeters into tissue, providing a favorable dose distribution for episcleral applications where the treatment goal is to limit depth and minimize side-scatter to surrounding structures.

Because Y-90 is a pure beta emitter, shielding requirements are minimal compared to photon-emitting sources. Beta radiation is effectively attenuated by a few millimeters of material, which is designed to reduce radiation exposure to healthcare personnel during the procedure. The 64-hour half-life enables the source to decay to negligible activity within weeks, simplifying waste disposal for medical facilities.

Device specifications

LV Y-90 Disc

The LV Y-90 Disc is an FDA 510(k) cleared sealed brachytherapy source for episcleral brachytherapy of ocular tumors and benign growths (510(k) K193602). The source consists of a high-purity yttrium-89 foil hermetically sealed in a titanium capsule by laser welding, then activated in a nuclear reactor to produce Y-90.

• Available diameters: 6mm and 10mm
• Activity: configurable per order, up to 20 mCi at time of treatment
• Single-use, steam-sterilized at the treatment facility prior to use
• NRC regulation: 10 CFR 35.1000 (Subpart K)

iWand® applicator system

The iWand® manual radionuclide applicators are FDA Class I devices designed for hand-held episcleral application of the LV Y-90 Disc. Two types are available:

• iWand® A (anterior) — features a transparent polymer tip designed to shield beta radiation side-scatter while allowing visualization of the treatment site. Available in sizes matching both Y-90 Disc diameters.
• iWand® P (posterior) — features four fiber-optic guiding lights surrounding the Y-90 Disc well, connected to the LV light source (LS01) via 3 meters of thin fiber-optic cable. The lights are visible ophthalmoscopically and photographically when the applicator is positioned behind the eye, enabling the surgeon to confirm and document disc positioning over the target.

Both applicators are single-use, pre-sterilized with ethylene oxide, individually packaged, and weigh less than 8 grams.

Dosimetry

Monte Carlo dosimetry of the LV Y-90 Disc has been independently characterized by researchers at Northwell Health / Hofstra University. Their simulations using GATE/Geant4 demonstrated agreement between calculated and measured depth-dose curves, with dose rates validated against EBT3 film measurements.

A separate independent study compared the dose falloff characteristics of Y-90 and Ru-106/Rh-106 disc sources for ocular melanoma treatment using Monte Carlo methods.

The AAPM Task Group 221 report provides the recommended physics framework for commissioning and quality assurance of beta-emitting ocular brachytherapy sources.

Full citations for these publications, including disclosures of any author affiliations with Liberty Vision, are available on our Publications page.

Workflow overview

The LV Y-90 system is designed as an integrated brachytherapy platform. The following describes the procedural workflow as reported in published clinical implementations:

LV Y-90 integrated system

1. LV Y-90 Disc is ordered from Liberty Vision with specified activity and diameter
2. Disc arrives calibrated and ready for sterilization
3. Disc is steam-sterilized at the treatment facility
4. Disc is assembled into the single-use iWand applicator using the assembly stand
5. Treatment is delivered by hand-held episcleral application for the calculated duration (typically minutes)
6. Applicator is removed; no second surgery required
7. Source decays to background within weeks

For comparison: traditional I-125 plaque brachytherapy

The traditional plaque brachytherapy workflow, as described in ABS consensus guidelines and AAPM task group reports, involves a multi-step process: ordering individual I-125 (or Pd-103) seeds from a seed manufacturer, acquiring a gold plaque shell separately, manually loading seeds into the plaque, surgical implantation with sutures to attach the plaque to the sclera, multi-day continuous irradiation (typically 3–7 days) with the patient hospitalized, and a second surgery to remove the plaque. Treatment planning requires accounting for individual seed positions and activities.

The LV Y-90 system is designed to replace this multi-vendor, multi-day workflow with an integrated, single-session approach. Liberty Vision does not claim clinical superiority — the choice of brachytherapy approach depends on many clinical factors. The procedural differences described above are characteristics of the respective device workflows.

Radiation safety

Published reports from clinical implementations describe favorable radiation safety profiles for the LV Y-90 system. The beta emission is effectively shielded by the iWand applicator materials — the iWand A's transparent polymer tip is designed to block side-scatter, and beta radiation does not require the lead shielding or dedicated isolation rooms associated with photon-emitting plaque brachytherapy.

Radiation dosimeter monitoring during clinical implementations has been described in published reports. For full details, see the clinical implementation paper on our Publications page.

Implementing a Y-90 brachytherapy program

Institutions interested in implementing Y-90 ophthalmic brachytherapy can contact Liberty Vision for information about device qualification requirements, NRC/Agreement State licensing considerations, training and support, and ordering. Several institutions in the United States have implemented Y-90 ophthalmic brachytherapy programs using the LV Y-90 system, as described in published literature.