Room: Exhibit Hall
Purpose: The current methods used to display the dose distribution in radiotherapy are based on coloration of the isodose area, visualized using isodose lines or colour washes. We propose a novel method of displaying the dose distribution by adopting the Red Relief Image Map technique (Chiba T., Journal of the Japan Cartographic Association, 27-36, 45, 2007), which was developed in the field of digital terrain representation.
Methods: All dose-displaying methods currently use dose values only. However, our method uses the dose gradient at a given point in addition to the dose value. There are several colour models, including HSV, RGB, and CMYK. The HSV colour model was designed in accordance with how humans perceive colour, and it consists of three spaces in terms of hue, saturation and value (brightness). The RGB colour model is used mainly for representation and display of images in electronic systems, such as televisions and computers.The dose gradient (G) at a given point was defined as a function of the gradients of the X and Y directions using eight neighbouring points, namely, G = Sqrt(fxÂ² + fyÂ²), where fx and fy are the gradients for the X and Y directions, respectively. The dose gradients and dose values were normalized and then assigned to the saturation and value parameters in the HSV colour model. The hue parameter was a fixed value (i.e. 0, red colour). The HSV model was converted into the RGB model (image) to display on a computer monitor.
Results: The resulting RGB image presented a stereoscopic view and, compared with conventional coloration methods, aided visual monitoring of the dose variation.
Conclusion: The proposed method can potentially be used to improve visualization of the dose distribution. Efforts to optimize the parameters are ongoing.