Quantitative and qualitative application of clinical drawings for image-guided brachytherapy in cervical cancer patients

Introduction
Clinical drawings are integral part of image-guided adaptive brachytherapy (IGABT) of cervical cancer. It was used in EMBRACE study protocol as a useful tool. In our study clinical drawings from EMBRACE study were modified to include scales in all the dimensions for more accurate representation of various tumor related volumes. The aim of the present study was to understand patterns of tumor regression and relationship between gross tumor at diagnosis (GTVD) and high-risk clinical target volume (CTV-THR)/intermediate-risk clinical target volume (CTV-TIR) in brachytherapy (BRT), using modified clinical drawings.

Material and methods
42 cervical cancer patients, staged as FIGO IIB-IIIB according to EMBRACE study, were enrolled. Advanced schematic 3D mapping diagram (3D-MD) in axial, coronal, and sagittal orientations, with a measurement scale (grid with 10 mm distance) for precise assessment and documentation was applied (through MRI at diagnosis and during brachytherapy). Dimensions, including height, width, and thickness as well as volumes (GTVD, CTV-THR and CTV-TIR) were compared both qualitatively and quantitatively.

Results and conclusions
We found qualitative and quantitative correlation of the dimensions of final CTV-THR with initial GTVD. Meticulous mapping of tumor volumes can provide useful insights to CTV-THR volume during brachytherapy.