title: Quantitative comparison of thermal dose models in normal canine brain.
abstract: OBJECTIVE
  Minimally invasive thermal ablative therapies as alternatives to conventional surgical management of solid tumors and other pathologies is increasing owing to the potential benefits of performing these procedures in an outpatient setting with reduced complications and comorbidity. Magnetic resonance temperature imaging (MRTI) measurement allows existing thermal dose models to use the spatiotemporal temperature history to estimate the thermal damage to tissue. However, the various thermal dose models presented in the literature employ different parameters and thresholds, affecting the reliability of thermal dosimetry. In this study, the authors quantitatively compared three thermal dose models (Arrhenius rate process, CEM43, and threshold temperature) using the dice similarity coefficient (DSC).
  
  
  METHODS
  The DSC was used to compare the spatial overlap between the region of thermal damage as predicted by the models for in vivo normal canine brain during thermal therapy to the region of thermal damage as revealed by contrast-enhanced T1-weighted images acquired immediately after therapy (< 20 min). The outer edge of the hyperintense rim of the ablation region was used as the surrogate marker for the limits of thermal coagulation. The DSC was also used to investigate the impact of varying the thresholds on each models' ability to predict the zone of thermal necrosis.
  
  
  RESULTS
  At previously reported thresholds, the authors found that all three models showed good agreement (defined as DSC > 0.7) with post-treatment imaging. All three models examined across the range of commonly applied thresholds consistently showed highly accurate spatial overlap, low variability, and little dependence on temperature uncertainty. DSC values corresponding to cited thresholds were not significantly different from peak DSC values.
  
  
  CONCLUSIONS
  Thus, the authors conclude that the all three thermal dose models can be used as a reliable surrogate for postcontrast tissue damage verification imaging in rapid ablation procedures and can also be used to enhance the capability of MRTI to control thermal therapy in real time.
authors.affiliation: Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA.
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Yung
authors.forename: Anil
authors.initials: A
authors.lastname: Shetty
authors.forename: Andrew
authors.initials: A
authors.lastname: Elliott
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Weinberg
authors.forename: Roger J
authors.initials: RJ
authors.lastname: McNichols
authors.forename: Ashok
authors.initials: A
authors.lastname: Gowda
authors.forename: John D
authors.initials: JD
authors.lastname: Hazle
authors.forename: R Jason
authors.initials: RJ
authors.lastname: Stafford
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D001831:Body Temperature; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D001927:Brain Diseases / Q000628:therapy; D004285:Dogs; D006358:Hot Temperature / Q000627:therapeutic use*; D006979:Hyperthermia, Induced / Q000706:statistics & numerical data; D053685:Laser Therapy / Q000706:statistics & numerical data; D008279:Magnetic Resonance Imaging; D015233:Models, Statistical; D013816:Thermodynamics