Haptics Modelling for Digital Rectal Examinations

Digital Rectal Examination (DRE) plays a crucial role for diagnosing anorectal and prostate abnormalities. Despite its importance, training and learning is limited due to their unsighted nature. Haptics and simulation offer a viable alternative for enhancing the learning experience by allowing the trainees to train in safety whilst trainers are able to assess competency. We present results of our geometrical, deformation and haptics modelling for two key anatomical structures obtained from patient specific MRI scans, namely the rectum and the prostate. Rectum mobility and hardness are modelled via a centreline consisting of control and structure points that are ruled by a mass-spring model based on elastic energy. Prostate mobility, hardness, deformability and friction are modelled via a surface model consisting of colliding spheres interconnected by springs with elongation, flexion and torsion properties. Clinical input and model fine-tuning was provided by three consultants from clinical disciplines that routinely perform DREs. Our approach is modular with scope to support additional palpable anatomical structures and the potential to be used as a teaching and learning tool for DRE.