PMC

Performances of the proposed ultrasound Joule heat tomography under different electrical conductivity contrast (tumor to surrounding normal tissue). (a) CC^-, CC⁺ and CC⁺-CC^- versus electrical conductivity contrast. (b) The relative error (RE) versus electrical conductivity contrast. (c) shows Joule heat contrast without tumor inside JHC^-, Joule heat contrast of established target Joule heat distribution JHC*, Joule heat contrast of the imaging result JHC⁺ and JHC⁺-JHC^- versus electrical conductivity contrast. (d)-(f) show imaging results for tumors of electrical conductivity contrast 1.5, 3.5 and 6.0, respectively. (g)-(i) show corresponding line profiles of the imaging results and established target Joule heat distributions along the line cross the center of the phantom, marked by the white dotted line in (d)-(f), respectively.

(a) Diagram of the numerical phantom of a piece of homogeneous tissue with embedded tumors; (b) the target Joule heat density distribution calculated using FEM (normalized for each slice in order to visualize the detailed contrast); (c) reconstructed Joule heat density distribution using the proposed method. The three slices locate at x=-3.0, 0.0 and 3.0 cm, respectively. (d) The target Joule heat density distribution at x=0.0 cm as a 2D image; (e) the true Joule heat density distribution (FEM simulated) at x=0.0 cm without tumors inside; (f) reconstructed Joule heat density distribution at x=0.0 cm using the proposed UJHT method with unipolar pulses; (g) Joule heat density imaging by UJHT using bipolar ultrasound pulses; (h) line profiles along the white dotted lines in images (d)–(g).

The investigation results of the position dependency of the proposed imaging method for tumor scan application. (a) CC^-, CC⁺ and CC⁺-CC^- for tumors located at different position along x axis. (b) The relative error (RE) for tumors located at different position. (c) shows Joule heat contrast without tumor inside JHC^-, Joule heat contrast of established target Joule heat distribution JHC*, Joule heat contrast of imaging result JHC⁺ and JHC⁺-JHC^- for tumors located at different position. (d)-(f) show imaging results for tumors located at x=0.02, 1.6 and 3.0cm, respectively. (g)-(i) show corresponding line profiles of the imaging results and established target Joule heat distributions along the line as marked by the white dot line in (d)-(f), respectively. (j) and (k) display the imaging results for tumors located at x=3.0cm with disk-shaped electrodes of radius 2.0 and 2.6 cm, respectively, and (l) shows their line profiles along the white dotted lines as comparison to the target Joule heat distributions.

(a) Ion concentration distribution of cation and anion in an uncharged nanopore with/without Joule heating; (b) ion concentration distribution of cation and anion in a negatively charged nanopore with/without Joule heating, where (c) induced charge concentration in four different cases: Uncharged/negatively charged nanopore with/without Joule heating effects; (d) effect of surface charge density on transport-induced-charge (TIC). (The “JH” in the legend denotes Joule heating.)