Analisis Berat Badan terhadap Pergeseran Titik Koordinat X, Y, Z dengan Teknik Volumetric Modulated Arc Therapy pada Kasus Kanker Serviks di Instalasi Onkologi Radiasi Tzu Chi Hospital

Abstract

Background: Cervical cancer is one of the most common gynecological malignancies in Indonesia and globally. Radiotherapy is one of the primary treatment modalities for this disease. Volumetric Modulated Arc Therapy (VMAT), when combined with Cone Beam Computed Tomography (CBCT), is widely used to improve the precision of radiation delivery. This combination plays a crucial role in maintaining treatment accuracy, especially when patient position changes due to weight fluctuations.

Methods: This study aimed to investigate the correlation between patient weight and positional shifts in X, Y, and Z coordinates during VMAT verification in cervical cancer patients. A descriptive qualitative design with an experimental approach was used. A sample of 10 patients with normal and overweight Body Mass Index (BMI) categories was selected. Data collection included observation of treatment sessions, interviews with radiation staff, and documentation of CBCT verification results. Measurements were performed specifically during the 1st, 11th, and 21st treatment fractions to evaluate positional consistency during therapy.

Results: This study showed that patients in the overweight BMI group generally experienced greater coordinate shifts compared to those with a normal BMI. All recorded shifts were within acceptable tolerance limits, less than 0.5 cm. These results demonstrate that body weight affects positional stability during therapy and highlight the importance of careful and ongoing verification before each radiation administration.

Conclusions: There were no significant differences in X, Y, and Z coordinate shift values ​​between patients with normal and overweight BMI. Verification of patient position using CBCT before radiation, along with the application of the VMAT technique, has been shown to be accurate and effective in ensuring optimal care delivery.