Dosimetric Study Of Image-Guided Brachytherapy For Cervix Carcinoma Treatment At Komfo Anokye Teaching Hospital

Abstract

The study was conducted purposely to compare the dosimetric characteristics of 2D to 3D LDR; to compare their planning procedures, imaging, and dose distributions in both treatment modalities to provide recommendations for an easy transition from 2D LDR to 3D IGBT at KATH. The lack of spatial information on the tumour and OAR volumes and the inability to visualize the extent of the tumour and applicators in 3D results in suboptimal application technique planning with insufficient dose coverage for large tumours, which is a major limitation of brachytherapy treatment planning at KATH. Perspex and water were used in the construction of a water phantom for data collection of certain parameters such as air kerma strength of the sources and dose distribution across the phantom. Both 2D and 3D imaging modalities, X-ray and CT, were utilized and compared, including treatment planning procedures, to develop measurable data on the differences, advantages, and demerits of 2D LDR and 3D IGBT. To determine dosage distribution, cross-calibration measurement was performed to get the correction factor for the ion chamber used for the data collection, which was unavailable. The values obtained for KQQo, KT,P, KPOL, KSAT for cobalt were 8.892, 1.030, 0.975, and 8.854, respectively and the correction factor (DA, Q) for PTW 31010 was 3.240+0.06 x 106 Gy/C. Furthermore, the dose distribution in 2D is point-based and hence volumetric dose distribution is not considered as done in 3D forrmat, which implies that there may be doses beyond the 2 cm margin which are not accounted for during the treatment planning. This and poor imaging in 2D to visualize the crossing of the urethra artery and ureter verifies that point A is not a necessity in 3D LDR IGBT. 2D LDR may have come with some benefits. With the successful construction of the phantom, collection, and analysis of dosimetric parameters, it can be concluded that Image-guided brachytherapy is observed to be quite advantageous in a radioactive source and organ localization, treatment planning, safety, and even cost.