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Ophthalmic plaque brachytherapy: choroidal melanoma and retinoblastoma
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Paul T Finger, A Linn Murphree
Historically, the calculated dose delivered to the apex of a retinoblastoma (being treated primarily with brachytherapy) has been similar to the total dose given in primary EBRT: generally about 4000 cGy, with a range of 3500–4500 cGy. A brachytherapy dose of 4000 cGy to the apex of a retinoblastoma means that the base of a 6 or 7 mm high tumor as well as the tumor vessels and retinal vessels in the radiation field receive a dose of nearly 8000 cGy. Although radiation retinopathy can be seen following the primary treatment of retinoblastoma, it is unusual. This is not the case if brachytherapy is used to consolidate a tumor following primary neoadjuvant chemotherapy (chemoreduction). The following paragraph describes the dose adjustment required if brachytherapy follows platinum-based chemo-therapy. Brachytherapy following carboplatin-based systemic chemotherapy has an increased complication rate.
Discuss the pathological effects of ionising radiation
Published in Nathaniel Knox Cartwright, Petros Carvounis, Short Answer Questions for the MRCOphth Part 1, 2018
Nathaniel Knox Cartwright, Petros Carvounis
As well as increased risk of malignancy, due to DNA damage, atrophy and fibrosis may develop. This is partly due to reduced cell renewal and partly due to development of an endarteritis obliterans, probably caused by endothelial injury. Fibrosis may lead to restrictive lung disease and intestinal strictures. Fertility may be reduced. Cataracts can develop. Fibrosis of glandular tissues causes dry eyes and mouth. Radiation retinopathy occurs when endothelial damage allows leakage of plasma constituents into the surrounding tissues.
Radiation-Induced Optic Neuropathy: Literature Review
Published in Neuro-Ophthalmology, 2021
Fabrício Gomes Ataídes, Samuel Flávio Braga Reis Silva, Julianna Joanna Carvalho Moraes De Campos Baldin
A comparison could be made with the pathophysiology of radiation retinopathy, which is better understood, since this one is the most common complication of the posterior segment irradiation, but RION also occurs frequently. According to Seregard, radiation retinopathy is a chronic and progressive vasculopathy of the retinal capillaries primarily caused by endothelial injury to the vessel walls after RT, which causes capillary dilation, increased vascular permeability, endothelial sloughing, thrombosis, retinal cotton wool spots, retinal exudates and haemorrhages. Later, there is loss of pericytes as well as endothelial cells resulting in capillary drop-out and full-thickness retinal atrophy.25 All this knowledge about radiation retinopathy could lead a better understanding of RION, but in radiation retinopathy only the postlaminar optic nerve is involved. The clinical appearance is subtle with just progressive pallor of the optic nerve head.7,55,56 The pathogenesis is believed to include axonal necrosis or a combination of these.7
Radiation retinopathy intricacies and advances in management
Published in Seminars in Ophthalmology, 2022
Noraliz García-O’Farrill, Sangeethabalasri Pugazhendhi, Peter A. Karth, Allan A. Hunter
Radiation retinopathy is a chronic, progressive, vision-threatening complication from exposure to various radiation sources. It is often exhibited in patients undergoing intraocular tumor irradiation (such as for ocular melanoma and retinoblastoma) and orbital, periorbital, facial, nasopharyngeal, and intracranial irradiation. The incidence of radiation-induced retinopathy ranges from 3 to 20% and is largely determined by the source, dose, and type of irradiation used in oncological management, along with tumor and treatment characteristics.1