ruthenium plaque
Pronunciation: roo-THEE-nee-um
Radioactive disc containing ruthenium-106 used for brachytherapy of small to medium-sized ocular tumors.
Full Definition
Ruthenium-106 plaques are episcleral radioactive applicators used for brachytherapy of uveal melanomas and other intraocular tumors. The beta radiation from ruthenium-106 has a limited penetration depth (approximately 5mm), making it ideal for anterior tumors and small posterior lesions. These concave gold-backed discs come in various sizes (10-25mm diameter) and deliver precise radiation doses while minimizing exposure to surrounding healthy tissues. Treatment typically involves surgical placement of the plaque directly over the tumor base, followed by removal after 2-7 days depending on the prescribed dose. Ruthenium plaques are preferred over iodine-125 for tumors with limited thickness and anterior location.
Usage
Usage note: Specify Ru-106 to distinguish from other ruthenium isotopes not used clinically.
In Context
- "A 15mm ruthenium plaque was positioned over the iris melanoma for localized brachytherapy." — Surgical procedure note
- "The shallow choroidal melanoma was well-suited for ruthenium plaque therapy given its anterior location." — Treatment planning note