This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tumors, Subject name: Ophthalmology
[{'content': 'Treatment of small tumour of retinoblastoma is: \nSelect and explain. \nA. Enucleation, B. Eviceration, C. Brachy therapy, D. Chemotherapy', 'role': 'user'}, {'content': "Answer: C \nExplanation: (Brachytherapy) (360-Parson's 20th) (283-KH)Treatment of small tumours is by local modalities* Cryotherapy for by local modalities* Photocoagulation for posterior ones* Brochytherapy with 60CO or 125I (4000 rad (~ 40 Gy)* Retinoblastoma is the commonest intraocular malignancy in children and malignant melanoma of the choroid in adult.* Metastatic deposits most commonly located in the choroid.* Metastatic tumours are radio sensitive.* Chemo reduction followed by local therapy (cryotherpy, thermochemo therapy or brachytherapy) is recommended for large tumours (>12 mm diameter)* Radiotherapy (External beam radiotherapy i.e. EBRT or brachytherapy) combined with chemotherapy > chemotherapy is recommended for medium size tumours < 12 mm in diameter and < 8 mm in thickness", 'role': 'assistant'}]