Illumination profile characterization of a light device for the dosimetry of intra-pleural photodynamic therapy for mesothelioma.
BACKGROUND
Complete and homogeneous illumination of the pleural cavity is essential to the success of photodynamic therapy (PDT) for mesothelioma, but remains a challenge. Knowing the repartition and propagation of light around the light applicator could be the first step towards optimizing dosimetry. Here we propose a characterization method of the illumination profile of a specific light device.


METHODS
The light wand, made of a cylindrical diffuser located inside an endotracheal tube, was fixed in a tank filled with dilute 0.01% intralipid. Light dosimetry was performed around the tip of the wand using two complementary methods: direct measurements of light power with an isotropic probe and measurements of light distribution characterization.


RESULTS
Dosimetry with the isotropic probe showed an ellipse-shaped illumination. An optimized effective attenuation coefficient was deduced. Combined with the spatial representation, a theoretical illumination profile was established with iso-surfaces of fluence rate, defining a gradient light dose according to the distance from the diffuser.


CONCLUSIONS
A theoretical illumination profile of a light device was established and could be part of an intra-operative dosimetry system to improve light delivery during intrapleural PDT.
Univ. Lille, Inserm, CHU Lille, U1189 - ONCO-THAI - Image Assisted Laser Therapy for Oncology, F-59000 Lille, France; Department of Pulmonary and Thoracic Oncology, Lille University Hospital, Lille, France.
Camille
C
Munck
Univ. Lille, Inserm, CHU Lille, U1189 - ONCO-THAI - Image Assisted Laser Therapy for Oncology, F-59000 Lille, France.
Serge
S
Mordon
Univ. Lille, Inserm, CHU Lille, U1189 - ONCO-THAI - Image Assisted Laser Therapy for Oncology, F-59000 Lille, France. Electronic address: nacim.betrouni@inserm.fr.
Nacim
N
Betrouni
D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004359:Drug Therapy, Combination / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008027:Light; D008029:Lighting / Q000295:instrumentation* / Q000379:methods; D008654:Mesothelioma / Q000188:drug therapy*; D010778:Photochemotherapy / Q000295:instrumentation* / Q000379:methods; D010997:Pleural Neoplasms / Q000188:drug therapy*; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage
Dosimetry; Illumination profile; Intrapleural photodynamic therapy; Light device