Background and purpose
A patient with a left lower tarsal conjunctival melanoma was treated at the Nelune Comprehensive Cancer Centre in July 2020 using High Dose Rate (HDR) Brachytherapy (BT) with Iridium-192. The 79 year old patient had previously undergone excision of the lesion and local reconstruction which resulted in tethering of the eye. As a consequence, plaque brachytherapy was not a viable treatment option. There was a positive margin and the disease involved the inferior conjunctival fornix.
We designed a novel technique using a single channel source placed along the medial reconstructed eyelid. The source channel was stabilised with a hydraulic clamp that is attached to the treatment couch. The tip of the channel was secured flushed with the medial canthus. The patient underwent CT Simulation and a HDR Brachytherapy treatment plan was generated using the Oncentra Brachy Treatment Planning System (Elekta, AB, Stockholm, Sweden), delivering 36 Gy in 6 fractions, every second day. The dose limiting structure was the adjacent cornea.
The treatment was uneventful and well tolerated by the patient. There was only grade 1 conjunctival irritation with no other acute toxicity. The patient will continue to be followed up for late toxicities and disease outcome.
Miss Soo Min Heng –Soo Min Heng is a Medical Physics Specialist at the NCCC. She loves QA and has a coffee addiction.
Mr Simon Downes –Simon Downes is the Chief Physicist at the NCCC. He is also the chair of the Asia Pacific Special Interest Group and has previously accompanied a new Co-60 teletherapy source to PNG.