Models and measurements of light intensity changes during laser interstitial thermal therapy: implications for optical monitoring of the coagulation boundary location.
Phys Med Biol
; 48(4): 543-59, 2003 Feb 21.
Article
em En
| MEDLINE
| ID: mdl-12630747
ABSTRACT
We have developed a multi-region spherical Monte Carlo (MC) model to simulate the dynamic changes in light intensity measured during laser interstitial thermal therapy (LITT). Model predictions were validated experimentally in tissue-simulating albumen phantoms with well-characterized optical properties that vary dynamically with LITT in a way similar to tissue. For long treatments (2.5 W, approximately 1800 s), the transient light intensity changes demonstrated better qualitative agreement with a three-region MC model (with an inner layer of fully coagulated optical properties, a middle layer of partially coagulated properties and an outer region of native properties); for short treatments (4 W, approximately 240 s), better qualitative agreement was seen with a two-region MC model (with an inner layer of fully coagulated properties and outer region of native properties). These differences were attributed to differences in coagulation formation during low- and high-powered heating regimes, respectively. At the end of heating, a three-region coagulation zone was observed for both heating schemes. Quantitatively, final light intensity changes at the end of heating were compared with changes predicted by both two- and three-region MC for the same experimentally measured coagulation size and found to agree within approximately 30% for both models. The developed MC model helps lend insight into the nature of thermal coagulation events occurring for low and high power LITT irradiation schemes.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Albumina Sérica
/
Monitorização Intraoperatória
/
Fotocoagulação a Laser
/
Cirurgia Assistida por Computador
/
Terapia a Laser
/
Modelos Biológicos
Tipo de estudo:
Prognostic_studies
/
Qualitative_research
Idioma:
En
Revista:
Phys Med Biol
Ano de publicação:
2003
Tipo de documento:
Article