By conducting interviews, prototyping and user tests this thesis aims to explore the question how not-thought-trough interaction design can be improved by implementing thoughtful interaction design. To explore this is a cancer therapy software presented and investigated with the intention to improve the current interface and user experience. The study presents findings based on the methods used that highlights the importance of interaction aesthetics and thoughtful interaction design when designing cancer therapy software. This is followed by the designer implementing improvements based on the feedback from the test subjects. The final results show that interaction aesthetics and thoughtful interaction design is of high importance in designing cancer therapy software.