Region Of Interest (ROI) coding is a mechanism deployed in several image coding systems to enable different degrees of coding priority to specific regions of the image. JPEG2000 standard provides two ROI coding methods. However, both of them are based in mechanisms that scale the quantized??coefficients. This compels to encode the additional bit-planes needed for the scaling, causing a penalization in the overall coding performance, and the ROIs can not be??modified without a complete re-encoding of the image. This paper introduces two ROI coding methods that use Rate-distortion optimization techniques toprioritize arbitrary ROIs over the rest of the image without penalizing the overall coding performance. Experimental results suggest that the proposed methods achieve a close tooptimal accuracy, improving the Implicit ROI coding method in terms of ROI rate distortion performance.