Dosimetric evaluation of a newly designed LDR brachytherapy applicator for treatment of cervical cancer with extension into the lower vagina

Abstract

Abstract Currently, cervical cancer patients with extension into the lower vagina are being treated with a combination of the Fletcher-Suit applicator, which treats the cervix, and vaginal cylinders for the treatment of the lower vagina. With this treatment method, the patients receive two separate implants creating a greater uncertainty in the dose distribution and unnecessary patient inconvenience. In order to reduce uncertainty of the dose delivery and eliminate patient inconvenience, a new applicator was designed and fabricated at the University of Kentucky for treatment of cervical cancer extending into the lower vagina. The dosimetric characteristics of this applicator (referred to hereafter as The Meigooni applicator) were determined using experimental procedures. The measurements were performed using tissue equivalent phantom material (Solid Water TM) that was machined to accommodate the applicator and LiF TLD chips. The applicator was loaded with Cs-137 brachytherapy sources in a standard loading scheme. A similar experimental procedure was performed using the presently available Fletcher-Suit mini-ovoid applicator. The results obtained from both applicators were compared with the values calculated by two of the commercially available treatment planning systems. This project shows that this new applicator is a safe single treatment for cervical cancer that has extended into the lower vagina, and eliminates the need for two treatments.