Chapters authored
Treatment Practices in Optic Nerve Glioma
Optic nerve glioma (OPG) is a rare tumor in children and adolescents. It comprises 1–5% of central nervous system tumors. It can be sporadic or associated with the neurofibromatosis 1 (NF1) gene. These are usually slow-growing tumors and may remain localized to the optic nerve or can have encroached upon adjoining structures like optic chiasma, opposite optic nerve, and hypothalamus. So, there may be decreased or loss of vision, proptosis, focal neurological symptoms, precocious puberty, and short stature. Due to the involvement of these critical structures, its treatment should be based on multidisciplinary consensus. The treatment modalities include surgery, RT, and chemotherapy. The aim of the treatment should be to preserve vision. However, the timing and selection of optimal treatment modalities are always a clinical dilemma. Recently, there have been promising results with newer techniques of radiotherapy and chemotherapy.
Part of the book: Radiation Oncology
Intensity Modulated Radiation Therapy Plan (IMRT) Verification Using Indigenous Heterogeneous Phantom
The dose distribution given by intensity-modulated radiotherapy (IMRT) is highly conformal, compared to conventional radiotherapies; however, due to the presence of the large numbers of fields and irregular shape and size of the treatment segments, the accuracy of IMRT delivery needs to be verified via dose measurement. Different dosimetry techniques are available that measures part of or the whole treatment immediately before a patient is treated and give us the total treatment delivery picture. But the majority of the commercially available phantoms are of homogeneous density, whereas the actual human body is a complex medium of different density patterns. Additionally, the very few heterogeneous phantoms, which are available commercially (i.e., anthropomorphic phantoms) are very costly and are not procured by most of the radiotherapy centers, especially in developing countries. Therefore, an indigenous heterogeneous phantom has been designed to verify the dose distribution prior to patient treatment.
Part of the book: Dosimetry