ESTRO 2024 - Abstract Book

S5009

Physics - Radiomics, functional and biological imaging and outcome prediction

ESTRO 2024

Tracking SH in real-time across treatment allows for a spatio-temporal approach to parameter assessment and AOI identification. This study aims to develop a method for characterisation of SH in WTV using the spherical coordinate system (SCS) 2 and heatmaps.

Material/Methods:

Ten patients with locally advanced cervical cancer (LACC) receiving chemoradiotherapy (CRT) were imaged with fMRI using diffusion-weighted (DWI) and blood oxygen level dependant (BOLD) MRI. Imaging was performed prior to treatment (S1) and halfway through treatment (S2). Parameters derived from fMRI included apparent diffusion coefficient (ADC) and transverse relaxation rate (R2*). Parameter data was extracted from sagittal slices, within which tumour was identified. Each pixel within the volume is assigned coordinates as well as the parameter value expressed. Data from the volumes is combined to generate the WTV, where pixels are identified in three-dimensions using cartesian coordinates.

Coordinates were used to generate two-dimensional and three-dimensional scatter plots, in which the size and colour of each plot represents the parameter value, creating parameter heatmaps.

Using SCS, pixels were grouped within regional blocks (Figure 1 and Table 1) based on their location defined by coordinates. This was applied at S1 and S2. For each block, parameter values were averaged and compared across treatment.

Figure 1. Regional blocks by SCS

Block 1 θ=0-90 ϕ =0-90

Posterior, superior, left

Block 2

Posterior, superior, right