Medical Laser-Induced Thermotherapy - Models and Applications

Christian Sturesson

Research output: ThesisDoctoral Thesis (compilation)

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Abstract

Heat has long been utilised as a therapeutic tool in medicine. Laser-induced thermotherapy aims at achieving the local destruction of lesions, relying on the conversion of the light absorbed by the tissue into heat. In interstitial laser-induced thermotherapy, light is focused into thin optical fibres, which are placed deep into the tumour mass. The objective of this work was to increase the understanding of the physical and biological phenomena governing the response to laser-induced thermotherapy, with special reference to treatment of liver tumours and benign prostatic hyperplasia. Mathematical models were used to calculate the distribution of light absorption and the subsequent temperature distribution in laser-irradiated tissues. The models were used to investigate the influence on the temperature distribution of a number of different factors, such as the design of the laser probe, the number of fibres, the optical properties of the tissue, the duration of irradiation, blood perfusion and boundary conditions. New results concerning transurethral microwave thermotherapy were obtained by incorporating the distribution of absorbed microwaves into the model. Prototypes of new laser applicators for anatomically correct treatment of benign prostatic hyperplasia were developed and tested ex vivo. Experimental work on liver tumours pointed to the importance of eliminating the blood flow in the liver during treatment to reduce convective heat loss. In addition, it was shown that hepatic inflow occlusion during treatment increased the thermal sensitivity of tumour tissue. The dynamic influence of interstitial laser thermotherapy on liver perfusion was investigated using interstitial laser Doppler flowmetry. Vessel damage after the combined treatment of laser-induced heat treatment and photodynamic therapy was studied.
Original languageEnglish
QualificationDoctor
Awarding Institution
  • Atomic Physics
Supervisors/Advisors
  • [unknown], [unknown], Supervisor, External person
Award date1998 Oct 24
Publisher
ISBN (Print)91-628-3134-8
Publication statusPublished - 1998

Bibliographical note

Defence details

Date: 1998-10-24
Time: 10:15
Place: Lecture hall B, Department of Physics, Sölvegatan 14, Lund, Sweden

External reviewer(s)

Name: van Gemert, Martin J.C.
Title: Professor
Affiliation: Academic Medical Centre, Amsterdam, The Netherlands

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Article: I. C. Sturesson and S. Andersson-Engels, "A mathematical model for predicting the temperature distribution in laser-induced hyperthermia. Experimental evaluation and applications," Phys. Med. Biol. 40: 2037-2052, 1995.

Article: II. C. Sturesson, "Interstitial laser-induced thermotherapy: influence of carbonization on lesion size," Lasers Surg. Med. 22: 51-57, 1998.

Article: III. K. Ivarsson, J. Olsrud, C. Sturesson, P.H. Möller, B.R.R. Persson and K.-G. Tranberg, "A feedback interstitial diode laser (805 nm) thermotherapy system: ex vivo evaluation and mathematical modelling with one and four fibers," Lasers Surg. Med. 22: 86-96, 1998.

Article: IV. A.M.K. Nilsson, C. Sturesson, D.L. Liu, and S. Andersson-Engels, "Spectral measurements of the optical properties of tissue in conjunction with laser-induced thermotherapy," Appl. Opt. 37: 1256-1267, 1998.

Article: V. C. Sturesson, D.L. Liu, U. Stenram and S. Andersson-Engels, "Hepatic inflow occlusion increases the efficacy of interstitial laser-induced thermotherapy in rat," J. Surg. Res. 71: 67-72, 1997.

Article: VI. C. Sturesson, K. Ivarsson, S. Andersson-Engels, and K.-G. Tranberg, "Changes in local hepatic blood perfusion during interstitial laser-induced thermotherapy of normal rat liver measured by interstitial laser Doppler flowmetry," submitted to Lasers Med. Sci.

Article: VII. C. Sturesson, K. Ivarsson, S. Andersson-Engels, U. Stenram, and K.-G. Tranberg, "Interstitial laser-induced thermotherapy of a rat liver tumour: Effect of temperature and hepatic inflow occlusion," manuscript.

Article: VIII. D.L. Liu, S. Andersson-Engels, C. Sturesson, K. Svanberg, C.H. Håkansson and S. Svanberg, "Tumour vessel damage resulting from laser-induced hyperthermia alone and in combination with photodynamic therapy," Cancer Lett. 111: 157-165, 1997.

Article: IX. C. Sturesson and S. Andersson-Engels, "Theoretical analysis of transurethral laser-induced thermo-therapy for treatment of benign prostatic hyperplasia. Evaluation of a water-cooled applicator," Phys. Med. Biol. 41: 445-463, 1996.

Article: X. C. Sturesson and S. Andersson-Engels, "Tissue temperature control using a water-cooled applicator. Implications for transurethral laser-induced thermo-therapy of benign prostatic hyperplasia," Med. Phys. 24: 461-470, 1997.

Article: XI. C. Sturesson, J. Olsrud, M. Bolmsjö, B.R.R. Persson, A. Mattiasson, and S. Andersson-Engels, "Side-firing laser catheter for treatment of benign prostatic hyperplasia: ex vivo evaluation," manuscript.

Article: XII. M. Bolmsjö, C. Sturesson, L. Wagrell, S. Andersson-Engels, and A. Mattiasson, "Optimizing transurethral microwave thermotherapy: a model for studying power, blood flow, temperature variations and tissue destruction," Br. J. Urol. 81: 811-817, 1998.

Subject classification (UKÄ)

  • Atom and Molecular Physics and Optics

Free keywords

  • blood perfusion
  • mathematical modelling
  • liver tumours
  • Atomic and molecular physics
  • benign prostatic hyperplasia
  • Atom- och molekylärfysik
  • Fysicumarkivet A:1998:Sturesson
  • hyperthermia
  • Coagulation
  • tissue optical properties

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