387 © Springer Nature Singapore Pte Ltd. 2021 R. Garg, S. Bhatnagar (eds.), Textbook of Onco-Anesthesiology, https://doi.org/10.1007/978-981-16-0006-7_28 Anesthesia for Radiation Therapy Procedures Nishkarsh Gupta, Vinod Kumar, and Sachidanand Jee Bharati 28.1 Introduction Radiation therapy (RT) has been used as one of the important multidisciplinary modalities for the management of cancers for a long [1]. With time, RT has made much advancement with regards to the safety of its delivery and effectiveness on can- cer management. It remains an integral part of surgery and chemotherapy (CT) for various can- cers. RT may be the sole management option in various cases, it may be given concurrently with CT, or along with surgery. RT is also considered for symptomatic management in patients with advanced cancers. The duration, technique, dose, and related toxicities are variable and depend upon the primary diagnosis including the site and extent of cancer and treatment plan. In modern radiation oncology, anesthesia plays an increasingly important role in facilitat- ing RT. Anesthesiologists are often required to manage sedation for RT in children, provide anesthesia for intraoperative radiotherapy and brachytherapy. Sophisticated techniques of RT reduce tumor to a minimum without affecting normal tissue margins but these may not be effec- tive if the patient moves during the whole proce- dure [2]. This may be required for techniques like brachytherapy, intraoperative irradiation, and external beam treatment of children or mentally challenged persons. RT is often required in children for various cancers. Mostly, it requires multiple sessions and the child should stay immobile during the RT ses- sions. This mandates the need for the provision of sedation and/or anesthesia. Traditionally external beam radiotherapy (EBRT) is given following surgery to eliminate the micro-metastasis and reducing the chances of local recurrence. Intra- operative radiation therapy (IORT) is one the modalities wherein radiation therapy is adminis- tered during the surgical intervention itself, focused at the surgical bed with an indent to man- age any residual tumor. In recent times, IORT has become popular due to the availability of advanced radiation therapy delivery devices like mobile linear accelerators and self-shielding devices Providing anesthesia in these cases is particularly challenging due to remote monitor- ing and debilitating condition of cancer patients. Also nowadays in the era of organ preserva- tion, there is the constant endeavor of the physi- cians to place the radioactive source as close to the tumor with the help of brachytherapy cathe- ters [3]. Such placemen allow delivery of higher doses of radiations to the tumor cells with sparing of surrounding normal tissues [4]. The availabil- ity of newer artificial high activity isotopes, after- loading systems together with improved imaging and sophisticated dose planning techniques has led to the increasing role of brachytherapy [5]. N. Gupta (*) · V. Kumar · S. J. Bharati Department of Onco-Anaesthesia and Palliative Medicine, DR BRAIRCH, All India Institute of Medical Sciences, New Delhi, India 28