Ultrastructural alterations in extraocular muscles following iodine-125 brachytherapy for uveal melanoma.
OBJECTIVE
This study investigated the ultrastructural changes in extraocular muscles under which radioactive plaques had been placed for the treatment of uveal melanoma.


METHODS
At the time of plaque removal, biopsies were taken from four horizontal recti that had been left in situ over plaques and from one lateral rectus muscle that had been disinserted before brachytherapy. Normal lateral recti from enucleated eyes were used as controls. Iodine-125 seeds were used with a mean total activity of 54.04 mCi, remaining for an average of 149.62 hours over the sclera.


RESULTS
Muscles that had been left in situ over the radioactive plaques demonstrated a focal decrease in muscular tissue and increased fibroblasts and collagen. Electron microscopy showed increased collagen, loss of sarcoplasmic reticulum and swollen mitochondria. The disinserted muscle in the plaque group appeared unaffected.


CONCLUSIONS
Despite the theoretical shielding properties of plaques, leaving an extraocular muscle over the plaque may lead to several non-specific ultrastructural changes.
Kïratlï
Hayyam
H
Ocular Oncology Service, Hacettepe University School of Medicine, Ankara, Turkey. hkiratli@hacettepe.edu.tr
Yïlmaz
Pinar Topcu
PT
Sargon
Mustafa
M
D000328:Adult; D001918:Brachytherapy / Q000009:adverse effects*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008545:Melanoma / Q000532:radiotherapy* / Q000648:ultrastructure; D009801:Oculomotor Muscles / Q000528:radiation effects* / Q000648:ultrastructure*; D014604:Uveal Neoplasms / Q000532:radiotherapy* / Q000648:ultrastructure
D007457:Iodine Radioisotopes