ORIGINAL ARTICLE Local property characterization of prostate glands using inhomogeneous modeling based on tumor volume and location analysis Yeongjin Kim • Bummo Ahn • Jae Won Lee • Koon Ho Rha • Jung Kim Received: 19 June 2012 / Accepted: 29 October 2012 / Published online: 11 November 2012 Ó International Federation for Medical and Biological Engineering 2012 Abstract Mechanical property characterization of pros- tate tumors can enhance the results obtained by palpation by providing quantitative and precise diagnostic informa- tion to surgeons. The multi-focal characteristics of prostate tumors cause inhomogeneity and local property variance in the prostate glands, which is one reason for inaccurate property characterizations of the tumors. Therefore, bio- mechanical models should include inhomogeneity and local property variance by taking into consideration the anatomical information (location and volume) of the tumors. We developed six inhomogeneous local prostate models using the finite element method, which takes into account the location and volume information of prostate tumors. The models were divided into six different sec- tions: lateral apex, lateral mid, lateral base, medial apex, medial mid and medial base tumors. Information on the location and volume of prostate tumors was obtained using pathological analysis. The mechanical properties of pros- tate tumors were estimated using the developed model simulation and the ex vivo indentation experiment results from the human resected prostates. The results showed that the mean elastic moduli of the normal and tumoral regions were 14.7 and 41.6 kPa, respectively. Our models provided more reliable estimates of the elastic moduli than the conventionally used Hertz–Sneddon model, and the results from our model were more closely correlated with previous studies due to the inclusion of the anatomical information via inhomogeneous modeling. These six local models provide baseline property criteria for the diagnosis and localization of prostate tumors using the optimized elastic moduli of normal prostate tissues. Keywords Local mechanical properties  FEM  Prostate 1 Introduction The mechanical properties of biological tissues are important indicators of the tissues’ pathological states. For instance, prostate adenocarcinomas have higher cellular densities than normal tissue, and the pathological findings from prostate adenocarcinoma demonstrate that these tumors have well-defined gland patterns and are denser than normal tissue. Thus, these changes in the tissue increase the mechanical properties of the tumor [13, 21]. Mechanical diagnosis is one possible approach for detect- ing tumors using the mechanical property differences between normal and tumor tissues. Palpation is the most frequently used clinical diagnostic method used by urolo- gists to distinguish between malignant and benign tumors. However, the success rate of this technique is low [19], and Y. Kim and B. Ahn contributed equally. Y. Kim  J. Kim (&) Division of Mechanical Engineering, School of Mechanical, Aerospace and Systems Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea e-mail: jungkim@kaist.ac.kr B. Ahn The Simulation Group, Department of Radiology, Center for Integration of Medicine and Innovative Technology, Harvard Medical School, 65 Landsdowne Street, Cambridge, MA 02139, USA J. W. Lee Department of Urology, Jesaeng General Hospital, Soengnam, Republic of Korea K. H. Rha Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea 123 Med Biol Eng Comput (2013) 51:197–205 DOI 10.1007/s11517-012-0984-7