Paper Title
Estimation of Normal Tissue Tolerance Doses and Volume Effect for The Organs At Risk for Cervical Radiotherapy

Abstract
The purpose of this study is to analyze the dose given and volume effect to the organs at risk (OARS) for cervical cancer radiotherapy. This retrospective study, carried out in a part of northern Nigeria included fifty patients with different stages of cervical cancer who were treated with external beam radiotherapy technique between March 2012 and November 2013. Patients who had other gynecological malignancies were excluded. All patients underwent a Computed Tomography (CT) scan, imaged supine in treatment position using a flat table top insert. Treatment fields of Anterior-posterior (AP) and Posterior-anterior (PA) fields or a four Field technique (AP, PA, right and left lateral fields) were planned with 2 cm margins defined by the clinician from bony anatomy. Patients were treated with a 100 cm Source to Axis Distance (SAD) isocentric technique. An external beam radiotherapy treatment (EBRT) plan was developed for all patients, based on target volumes and organs at risk, delineated on the CT-scan. Index terms- Volume effect, External Beam Radiotherapy, OARS, Cervical cancer.