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Focal laser ablation of prostate cancer: numerical simulation of temperature and damage distribution.

Marqa MF, Colin P, Nevoux P, Mordon SR, Betrouni N - Biomed Eng Online (2011)

Bottom Line: An effective method to perform pre-treatment planning of this therapy is computer simulation.The model was validated by comparing the simulated necrosis volume to the results obtained in vivo on (MRI) and by histological analysis. 3 iso-damage temperatures were considered 43° C, 45° C and 50° C.It needs further more evaluation to allow to FLA to become a widely applied surgical method.

View Article: PubMed Central - HTML - PubMed

Affiliation: Inserm (French National Institute of Health and Medical Research), U703, 152 rue du Docteur Yersin, 59120 Loos, France.

ABSTRACT

Background: The use of minimally invasive ablative techniques in the management of patients with low grade and localized prostate tumours could represent a treatment option between active surveillance and radical therapy. Focal laser ablation (FLA) could be one of these treatment modalities. Dosimetry planning and conformation of the treated area to the tumor remain major issues, especially when, several fibers are required. An effective method to perform pre-treatment planning of this therapy is computer simulation. In this study we present an in vivo validation of a mathematical model.

Methods: The simulation model is based on finite elements method (FEM) to solve the bio-heat and the thermal damage equations. Laser irradiation was performed with a 980 nm laser diode system (5 W, 75 s). Light was transmitted using a cylindrical diffusing fiber inserted inside a preclinical animal prostate cancer model induced in Copenhagen rats. Non-enhanced T2-weighted and dynamic gadolinium-enhanced T1-weighted MR imaging examinations were performed at baseline and 48 hours after the procedure. The model was validated by comparing the simulated necrosis volume to the results obtained in vivo on (MRI) and by histological analysis. 3 iso-damage temperatures were considered 43° C, 45° C and 50° C.

Results: The mean volume of the tissue necrosis, estimated from the histological analyses was 0.974 ± 0.059 cc and 0.98 ± 0.052 cc on the 48 h MR images. For the simulation model, volumes were: 1.38 cc when T = 43° C, 1.1 cc for T = 45°C and 0.99 cc when T = 50 C°.

Conclusions: In this study, a clear correlation was established between simulation and in vivo experiments of FLA for prostate cancer.Simulation is a promising planning technique for this therapy. It needs further more evaluation to allow to FLA to become a widely applied surgical method.

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(a) Pre-treatment MR image of the rat. (b) Post-treatment MR image with the visualization of the necrosis. The image is in a different plane than image (a). (c) The tumor after treatment and excision. (d) Histological tumor slice with green filter to enhance the circular limits of the coagolative necrosis (black arrows).
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Figure 1: (a) Pre-treatment MR image of the rat. (b) Post-treatment MR image with the visualization of the necrosis. The image is in a different plane than image (a). (c) The tumor after treatment and excision. (d) Histological tumor slice with green filter to enhance the circular limits of the coagolative necrosis (black arrows).

Mentions: One hour before the procedure, a multi-spectral Magnetic Resonance Imaging (MRI) acquisition was performed on the animals using a 7 Tesla MRI unit (Biospec, Bruker BioSpin SA, USA). Acquisitions included T2 weighted (T2W) images and dynamic contrast enhanced T1 (DCE) images. The MR images were used for the pre-treatment planning of the procedure by defining the fiber trajectory (Figure 1.a). The axis and depth of optimal fiber implantation were spotted on these image sequences. The purpose of this identification was to avoid fiber implantation in a spontaneously necrotic area.


Focal laser ablation of prostate cancer: numerical simulation of temperature and damage distribution.

Marqa MF, Colin P, Nevoux P, Mordon SR, Betrouni N - Biomed Eng Online (2011)

(a) Pre-treatment MR image of the rat. (b) Post-treatment MR image with the visualization of the necrosis. The image is in a different plane than image (a). (c) The tumor after treatment and excision. (d) Histological tumor slice with green filter to enhance the circular limits of the coagolative necrosis (black arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117748&req=5

Figure 1: (a) Pre-treatment MR image of the rat. (b) Post-treatment MR image with the visualization of the necrosis. The image is in a different plane than image (a). (c) The tumor after treatment and excision. (d) Histological tumor slice with green filter to enhance the circular limits of the coagolative necrosis (black arrows).
Mentions: One hour before the procedure, a multi-spectral Magnetic Resonance Imaging (MRI) acquisition was performed on the animals using a 7 Tesla MRI unit (Biospec, Bruker BioSpin SA, USA). Acquisitions included T2 weighted (T2W) images and dynamic contrast enhanced T1 (DCE) images. The MR images were used for the pre-treatment planning of the procedure by defining the fiber trajectory (Figure 1.a). The axis and depth of optimal fiber implantation were spotted on these image sequences. The purpose of this identification was to avoid fiber implantation in a spontaneously necrotic area.

Bottom Line: An effective method to perform pre-treatment planning of this therapy is computer simulation.The model was validated by comparing the simulated necrosis volume to the results obtained in vivo on (MRI) and by histological analysis. 3 iso-damage temperatures were considered 43° C, 45° C and 50° C.It needs further more evaluation to allow to FLA to become a widely applied surgical method.

View Article: PubMed Central - HTML - PubMed

Affiliation: Inserm (French National Institute of Health and Medical Research), U703, 152 rue du Docteur Yersin, 59120 Loos, France.

ABSTRACT

Background: The use of minimally invasive ablative techniques in the management of patients with low grade and localized prostate tumours could represent a treatment option between active surveillance and radical therapy. Focal laser ablation (FLA) could be one of these treatment modalities. Dosimetry planning and conformation of the treated area to the tumor remain major issues, especially when, several fibers are required. An effective method to perform pre-treatment planning of this therapy is computer simulation. In this study we present an in vivo validation of a mathematical model.

Methods: The simulation model is based on finite elements method (FEM) to solve the bio-heat and the thermal damage equations. Laser irradiation was performed with a 980 nm laser diode system (5 W, 75 s). Light was transmitted using a cylindrical diffusing fiber inserted inside a preclinical animal prostate cancer model induced in Copenhagen rats. Non-enhanced T2-weighted and dynamic gadolinium-enhanced T1-weighted MR imaging examinations were performed at baseline and 48 hours after the procedure. The model was validated by comparing the simulated necrosis volume to the results obtained in vivo on (MRI) and by histological analysis. 3 iso-damage temperatures were considered 43° C, 45° C and 50° C.

Results: The mean volume of the tissue necrosis, estimated from the histological analyses was 0.974 ± 0.059 cc and 0.98 ± 0.052 cc on the 48 h MR images. For the simulation model, volumes were: 1.38 cc when T = 43° C, 1.1 cc for T = 45°C and 0.99 cc when T = 50 C°.

Conclusions: In this study, a clear correlation was established between simulation and in vivo experiments of FLA for prostate cancer.Simulation is a promising planning technique for this therapy. It needs further more evaluation to allow to FLA to become a widely applied surgical method.

Show MeSH
Related in: MedlinePlus