noun
radioactive small source
Technical term used in radiation therapy and nuclear medicine; refers to a small encapsulated radioactive material placed inside or near a tumor.
小線源治療は、前立腺がんに対して有効な選択肢の一つです。
Brachytherapy using a radioactive small source is one effective option for prostate cancer.
Compound of 小 (small) + 線源 (radiation source). The term 線源 itself is a modern technical coinage from 線 (ray) and 源 (source).