2D brachytherapy planning versus 3D brachytherapy planning for patients with cervical cancer

Abstract

Research Aims The purpose of this study is to compare 2D HDR Brachytherapy planning and 3D HDR Brachytherapy planning in terms of dose distribution in order to accurately determine bladder and rectal doses. Further research questions were explored to determine whether relationships existed between Computer Tomography volumes and bladder and rectum dose. Methodology The 30 female patients that volunteered for the study were conveniently selected. Their age and ethnic group did not contribute to their selection. All participants were prepared for cervical HDR Brachytherapy. The Brachytherapy templates were computer generated and treatments were given based on the templates. They then had a Computer Tomography (CT) scan (3D data set) of the pelvis. The computer generated templates for 2D Brachytherapy planning were applied to the CT data set i.e. 2DBP. The plans were optimised to take into consideration the dose to the bladder and the rectum i.e. 3DBP. The 2DBP and the 3DBP were then evaluated in order to determine which method of planning yielded more acceptable dose distributions to the bladder and rectum. Results Significant differences in dose distribution were noted on comparison of 2DBP and 3DBP. A significant relationship was noted in respect of bladder mean dose and rectum mean dose. 3DBP proved to be more efficient in yielding lower mean dose to the bladder and the rectum. Whilst a significant relationship was noted in respect of bladder maximum dose, an insignificant relationship was noted for rectum maximum dose. Therefore, the efficiency of 3DBP to yield lower bladder maximum dose was established but its efficiency to yield lower rectum maximum dose is questionable. This has implications for the management of patients’ with cervical cancer who require cervical Brachytherapy. Recommendations It is imperative that imaging modalities be used for the accurate planning of cervical Brachytherapy. This study recommends that CT be used for HDR Brachytherapy planning by proving its greater efficiency compared to template planning.