title: Shape-based reconstruction for transrectal diffuse optical tomography monitoring of photothermal focal therapy of prostate cancer: simulation studies.
abstract: We develop and demonstrate a simple shape-based approach for diffuse optical tomographic reconstruction of coagulative lesions generated during interstitial photothermal therapy (PTT) of the prostate. The shape-based reconstruction assumes a simple ellipsoid shape, matching the general dimensions of a cylindrical diffusing fiber used for light delivery in current clinical studies of PTT in focal prostate cancer. The specific requirement is to accurately define the border between the photothermal lesion and native tissue as the photothermal lesion grows, with an accuracy of ? 1 ?? mm , so treatment can be terminated before there is damage to the rectal wall. To demonstrate the feasibility of the shape-based diffuse optical tomography reconstruction, simulated data were generated based on forward calculations in known geometries that include the prostate, rectum, and lesions of varying dimensions. The only source of optical contrast between the lesion and prostate was increased scattering in the lesion, as is typically observed with coagulation. With noise added to these forward calculations, lesion dimensions were reconstructed using the shape-based method. This approach for reconstruction is shown to be feasible and sufficiently accurate for lesions that are within 4 mm from the rectal wall. The method was also robust for irregularly shaped lesions.
authors.affiliation: University of Toronto, Department of Radiation Oncology, Toronto, Ontario, CanadabUniversity of Toronto, Institute of Biomaterials and Biomedical Engineering, Toronto, Ontario, CanadacUniversity Health Network, Techna Institute, Toronto, Ontario, CanadadUniversity Health Network, Radiation Medicine Program, Toronto, Ontario, Canada.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Weersink
authors.affiliation: University of Toronto, Department of Medical Biophysics, Toronto, Ontario, Canada.
authors.forename: Sahil
authors.initials: S
authors.lastname: Chaudhary
authors.affiliation: University of Toronto, Department of Medical Biophysics, Toronto, Ontario, Canada.
authors.forename: Kenwrick
authors.initials: K
authors.lastname: Mayo
authors.affiliation: University of Toronto, Department of Medical Biophysics, Toronto, Ontario, Canada.
authors.forename: Jie
authors.initials: J
authors.lastname: He
authors.affiliation: University Health Network, Techna Institute, Toronto, Ontario, CanadaeUniversity of Toronto, Department of Medical Biophysics, Toronto, Ontario, CanadafUniversity Health Network, Ontario Cancer Institute, Toronto, Ontario, Canada.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Wilson
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D015233:Models, Statistical; D010789:Phototherapy / Q000379:methods*; D011467:Prostate / Q000473:pathology; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy*; D012007:Rectum / Q000473:pathology; D015203:Reproducibility of Results; D041622:Tomography, Optical / Q000379:methods*