The short and long term stability of the Diomed 630 PDT laser with attached fiberoptic microlens was evaluated by
means of integrating sphere, power meter and a calorimetric system. The calorimeter system was designed as a thermal
mug with absorbing media (dye and water). Both the tip of the irradiation fiber and the detection probe of a
thermocouple thermometer were positioned inside the dye solution and stirred during the measurements. The
calorimetric system yielded measurement results consistent with the other two methods, and similar long term variations
were observed by all methods. With an indicated laser power of 1 W, the detectors' readings ranged from 0.66 to 1.29
W. For short term stability study, the deviation of laser output assessed by integrating sphere, power meter and
calorimetric system were 0.3%, 0.1% and 2.8% with long term deviations of 13%, 7% and 9% respectively. This wide
variation in the laser output implies the needs to establish quality control procedures involving measurements pre and
post PDT procedures. The calorimetric system has been demonstrated to be a powerful tool for clinical laser QA and
maintenance of the calibration factor of the detectors used in this work.
Multifocal recurrence of in-situ squamous cell cancer of the oral cavity, pharynx and vocal cord
following surgical failure can be a therapeutic dilemma. Salvage surgery or radiation may be an option but
morbidity can be significant. We evaluated the potential role of low dose Photofrin (1.2mg/Kg)
Photodynamic Therapy for this cohort of patients.
A total of 25 patients with multifocal recurrent in-situ squamous cell cancer of the oral cavity,
pharynx and vocal cord who had failed local resection, and where additional surgery or radiation therapy
would likely result in permanent morbidity, were offered Photodynamic Therapy. PDT consisted of off
label infusion of Photofrin (1.2mg/kg) followed 48 hours later by illumination at 630nm employing a light
diffuser (300J) and/or microlens (150Jcm2).
All patients completed their prescribed PDT and no patient has been lost to follow up (minimum 1
year). No photosensitivity reactions were noted. No significant morbidity was seen. All patients were able
to maintain oral nutrition. Procedure related pain was well controlled by one week of oral narcotics. At
one month post PDT all patients were biopsy negative in the treatment region and no failures within the
treatment region have been noted. No fibrosis or permanent PDT morbidity has been seen with follow up to
three years. Vocal cord and voice function were excellent.
Three patients developed new regions of in-situ disease outside the PDT fields, two underwent additional
PDT and one had laser resection.
Low dose Photofrin PDT offers excellent palliation and durable local control of recurrent in-situ
squamous cell cancers of the oral cavity, pharynx and true cords. This is a well tolerated therapy. Low
dose Photofrin appears to improve selectivity and minimize normal tissue injury. It should be tested in a
larger patient population.
We reviewed the outcome of combined photodynamic therapy (PDT) and high dose rate brachytherapy
(HDR) for patients with symptomatic obstruction from endobronchial non-small cell lung cancer. Methods: Nine
patients who received combined PDT and HDR for endobronchial cancers were identified and their charts reviewed.
The patients were eight males and one female aged 52-73 at diagnosis, initially presenting with various stages of disease:
stage IA (N=1), stage IIA (N=1), stage III (N=6), and stage IV (N=1). Intervention was with HDR (500 cGy to 5 mm
once weekly for 3 weeks) and PDT (2 mg/kg Photofrin, followed by 200 J/cm2 illumination 48 hours post infusion).
Treatment group 1 (TG-1, N=7) received HDR first; Treatment group 2 (TG-2, N=2) received PDT first. Patients were
followed by regular bronchoscopies. Results: Treatments were well tolerated, all patients completed therapy, and none
were lost to follow-up. In TG-1, local tumor control was achieved in six of seven patients for: 3 months (until death), 15
months, 2+ years (until death), 2+ years (ongoing), and 5+ years (ongoing, N=2). In TG-2, local control was achieved in
only one patient, for 84 days. Morbidities included: stenosis and/or other reversible benign local tissue reactions (N=8);
photosensitivity reaction (N=2), and self-limited pleural effusion (N=2). Conclusions: Combined HDR/PDT treatment
for endobronchial tumors is well tolerated and can achieve prolonged local control with acceptable morbidity when PDT
follows HDR and when the spacing between treatments is one month or less. This treatment regimen should be studied
in a larger patient population.
KEYWORDS: Principal component analysis, Skin, Monte Carlo methods, Reflectivity, Imaging systems, In vivo imaging, Data modeling, Melanoma, Algorithm development, Tissue optics
Early detection of malignant melanoma is critical to improve the survival rates of patients with this aggressive malignancy. We constructed an imaging system employing two liquid-crystal tunable filters to acquire in vivo spectral images of dysplastic lesions from patients at 31 wavelengths from 500 to 950nm. These reflectance images were analyzed in search of optical signatures for quantitative characterization of dysplastic nevi and malignant melanoma. A principal component analysis (PCA) algorithm was developed to examine the spectral imaging data in the component space and an index of spreading of clustering pixels (SCP) was defined to measure the degree of clustering in the distribution of image pixel scores in a component space. We found that SCP of differential polarimetric images correlate strongly with the degree of dysplasia for 4 lesions. However, many questions remain unanswered on the relations between PCA results and the spatial and spectral characteristics of the image data because of limited spectral image data from the patients. To fully improve our understanding on the multivariate analysis of spectral imaging data, we have developed a parallel Monte Carlo code to efficiently generate reflectance images from given distribution of optical parameters in a skin lesion phantom. With this tool, we have investigated numerically the dependence of score distribution and SCP in the component sub-spaces on lesion size and position. These numerical results provide a foundation for our future study to identify optical signature of dysplastic lesion and melanoma in the skin.
Limited therapeutic options exist when chest wall recurrence form breast cancer progresses despite standard salvage treatment. As photodynamic therapy offers excellent response for cutaneous lesions this may be a possible indication for PDT. A total of 102 treatment fields were illuminated on 9 women with biopsy proven chest wall recurrence of breast cancer which was progressing despite salvage surgery, radiation, and chemi-hormonal therapy. PDT consisted of outpatient IV infusion of Photofrin at 0.8 mg/kg followed 48 hours laser by illumination at 140-170 J/cm2 via a KTP Yag laser coupled to a dye unit. No patient was lost to follow up. At 6 months post PDT; complete response, defined as total lesion elimination was 89 percent, partial response 8 percent, and no response 3 percent. No photosensitivity was seen and no patient developed scarring, fibrosis, or healing difficulties. Low dose Photofrin induced PDT is very active against chest wall lesions. Despite fragile and heavily pre-treated tissues, excellent clinical and cosmetic outcome was obtained. PDT is an underutilized modality for this indication.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.