Medical Imaging Processing on a Big Data platform using Python: Experiences with Heterogeneous and Homogeneous Architectures.

The apparition of new paradigms, programming models, and languages that offer better programmability and better performance turns the implementation of current scientific applications into a less time-consuming task than years ago. One significant example of this trend is the MapReduce programming model and its implementation using Apache Spark. Nowadays, this programming model is mainly used for data analysis and machine learning applications, although it has been expanded to its usage in the HPC community. On the side of programming languages, Python has positioned itself as an alternative to other scientific programming languages, such as Matlab or Julia. In this work we explore the capabilities of Python and Apache Spark as partners in the implementation of the backprojection operator of a CT reconstruction application. We present two interesting approaches with two different types of architectures: a heterogeneous architecture including NVidia GPUs and a full performance CPU mode with the compatibility with C/C++ native source code. We experimentally demonstrate that current CPU-based implementations scale with the number of computational units.