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Temperature control and light penetration in a feedback interstitial laser thermotherapy system

Möller, P. H. LU ; Lindberg, L. LU ; Henriksson, P. H. LU ; Persson, B. R.R. LU and Tranberg, K. G. LU (1996) In International Journal of Hyperthermia 12(1). p.49-63
Abstract

The aim of this study was to describe the performance of a closed loop interstitial laser thermotherapy system in processed liver and to demonstrate its suitability for treating a vascularized tumour in vivo. The thermotherapy system consisted of an Nd:YAG laser and a temperature feedback circuit including an automatic thermometry system and thermistor probes. Experiments in processed liver were performed with a sapphire probe and temperature control at a distance of 10 mm. In most experiments at 1-2 W, and in half of the experiments at 3 W, there was no carbonization, a moderate change in the light penetration and excellent control of the temperature. In experiments with output powers of 4-5 W there was carbonization with rapid... (More)

The aim of this study was to describe the performance of a closed loop interstitial laser thermotherapy system in processed liver and to demonstrate its suitability for treating a vascularized tumour in vivo. The thermotherapy system consisted of an Nd:YAG laser and a temperature feedback circuit including an automatic thermometry system and thermistor probes. Experiments in processed liver were performed with a sapphire probe and temperature control at a distance of 10 mm. In most experiments at 1-2 W, and in half of the experiments at 3 W, there was no carbonization, a moderate change in the light penetration and excellent control of the temperature. In experiments with output powers of 4-5 W there was carbonization with rapid deterioration of light penetration and impaired control of the temperature. Carbonization affected the distribution of temperatures, which were lower below, and higher above, the laser tip in experiments with carbonization as compared to experiments without carbonization. Treatment of an adenocarcinoma implanted into rat liver was performed at 2 W with a bare fibre and without blood inflow occlusion. The feedback thermistor probe was placed 3 mm outside the margin of the tumour (largest diameter 9.5 ± 0.3 mm (mean ± SEM)). Temperature control and light penetration characteristics were similar to those found in vitro. No tumour could be demonstrated at sacrifice 6 days later. It is concluded that a closed loop feedback system can produce stable and reproducible local hyperthermia, that it performs better when carbonization is avoided and light penetration is preserved and that it has a great potential for interstitial thermotherapy of malignant tumours.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Adenocarcinoma, Bare fibre, Interstitial hyperthermia, Nd-YAG laser, Rat, Sapphire probe
in
International Journal of Hyperthermia
volume
12
issue
1
pages
15 pages
publisher
Taylor & Francis
external identifiers
  • scopus:0029919161
  • pmid:8676008
ISSN
0265-6736
DOI
10.3109/02656739609023689
language
English
LU publication?
yes
id
d4984850-35d7-4425-b6d8-6af0d0b9b6a0
date added to LUP
2019-06-15 17:02:17
date last changed
2019-12-03 02:13:08
@article{d4984850-35d7-4425-b6d8-6af0d0b9b6a0,
  abstract     = {<p>The aim of this study was to describe the performance of a closed loop interstitial laser thermotherapy system in processed liver and to demonstrate its suitability for treating a vascularized tumour in vivo. The thermotherapy system consisted of an Nd:YAG laser and a temperature feedback circuit including an automatic thermometry system and thermistor probes. Experiments in processed liver were performed with a sapphire probe and temperature control at a distance of 10 mm. In most experiments at 1-2 W, and in half of the experiments at 3 W, there was no carbonization, a moderate change in the light penetration and excellent control of the temperature. In experiments with output powers of 4-5 W there was carbonization with rapid deterioration of light penetration and impaired control of the temperature. Carbonization affected the distribution of temperatures, which were lower below, and higher above, the laser tip in experiments with carbonization as compared to experiments without carbonization. Treatment of an adenocarcinoma implanted into rat liver was performed at 2 W with a bare fibre and without blood inflow occlusion. The feedback thermistor probe was placed 3 mm outside the margin of the tumour (largest diameter 9.5 ± 0.3 mm (mean ± SEM)). Temperature control and light penetration characteristics were similar to those found in vitro. No tumour could be demonstrated at sacrifice 6 days later. It is concluded that a closed loop feedback system can produce stable and reproducible local hyperthermia, that it performs better when carbonization is avoided and light penetration is preserved and that it has a great potential for interstitial thermotherapy of malignant tumours.</p>},
  author       = {Möller, P. H. and Lindberg, L. and Henriksson, P. H. and Persson, B. R.R. and Tranberg, K. G.},
  issn         = {0265-6736},
  language     = {eng},
  month        = {01},
  number       = {1},
  pages        = {49--63},
  publisher    = {Taylor & Francis},
  series       = {International Journal of Hyperthermia},
  title        = {Temperature control and light penetration in a feedback interstitial laser thermotherapy system},
  url          = {http://dx.doi.org/10.3109/02656739609023689},
  doi          = {10.3109/02656739609023689},
  volume       = {12},
  year         = {1996},
}