Biomedical subjects

Stephen M Hahn

Publications and source records attributed to Stephen M Hahn.

At least 37 records · Page 2Linked to original sources

PubMed2004

Patterns of recurrence in patients treated with photodynamic therapy for intraperitoneal carcinomatosis and sarcomatosis.

The purpose of this study was to evaluate the patterns of recurrence in patients treated with Photofrin-mediated intraperitoneal photodynamic therapy (IP PDT). Sixty-six patients with gastrointestinal cancers, ovarian cancers, and sarcomas have been enrolled to date and 51 patients underwent IP PDT. Photofrin, 2.5 mg/kg, was administered intravenously 48 h prior to surgical debulking and intraoperative light treatment. Forty-five, and 49 patients were evaluable for response rates, and patterns of recurrence, respectively. Response to treatment was evaluated by CT or MRI scans of the abdomen and pelvis every 3 months. Patterns of recurrence were determined by evaluating the abdomen as a combination of different treatment regions. Of the 51 patients enrolled and treated with IP PDT two are alive without evidence of recurrence. Eleven of 45 patients showed no evidence of recurrence 3 months after treatment. No evidence of recurrence was noted in 7/17 sarcoma patients, 2 of 13 ovarian cancer patients, and 2 of 15 gastrointestinal cancer patients. The most common site of recurrence as determined by radiographs was the pelvis, which was noted in 19 of 49 (39%) patients. The presence of gross residual disease before light treatment (as determined by the attending surgeon) did not affect the site of recurrence. When studying those patients who had only locoregional recurrence, 9 of 33 evaluated radiographically and 10 of 24 evaluated operatively recurred only in peritoneal areas not previously involved with gross disease. The pelvis was the site with the highest rate of recurrence after IP PDT. A significant minority of patients recurred only in sites not previously involved with gross disease. Patients with gross residual disease before light therapy had similar recurrence rates to those without gross residual disease. Since sites involved with gross residual tumor often received boost doses of light, this could suggest a dose-response relationship for IP PDT.

Adult↗

PubMed2003

Farnesyltransferase inhibitors: an overview of the results of preclinical and clinical investigations.

This article presents an overview of preclinical studies and clinical trials of a number of independently derived farnesyltransferase inhibitors (FTIs). Potential targets and biological modes of action of FTIs are discussed, and the results of clinical trials are summarized. The significant efficacy of FTIs as single or combined agents in preclinical studies stands in contrast with only moderate effects in clinical Phase II-III trials. These results reveal a substantial gap in the understanding of the complex activity of FTIs and their interactions with cytotoxic agents. We conclude that the rational combination of FTIs with other therapies, taking into account the biological activities of the individual agents, may improve the clinical results obtained with FTIs.

Alkyl and Aryl Transferases↗

PubMed2003

The RAS signal transduction pathway and its role in radiation sensitivity.

RAS has been shown to increase radiation resistance. Upstream and downstream pathways from RAS could thus be targets for manipulation of radiosensitivity. EGFR expression and AKT phosphorylation are also associated with the response to radiation. A retrospective study evaluating EGFR and AKT in patients treated with multimodality therapy found a significant association between P-AKT and treatment failure. Moreover, these data are strengthened by in vitro studies showing that inhibition of EGFR, RAS, PI3K, and AKT radiosensitized cancer cell lines. We have previously shown that PI3K is a mediator of RAS-induced radiation resistance. We now suggest that EGFR, which is upstream of PI3K, may also mediate resistance through a common pathway. In addition to EGFR and RAS, PTEN can also regulate the PI3K pathway. Identifying a common signal for EGFR, RAS, or PTEN that results in radiation resistance may uncover targets for developing molecular-based radiosensitization protocols for tumors resistant to radiation and thus improve local control.

Animals↗

PubMed2003

Phase I combination trial of gemcitabine, paclitaxel, and carboplatin in patients with advanced malignancy.

PURPOSE: We performed a phase I trial of carboplatin and paclitaxel in combination with gemcitabine in order to determine the tolerability of this triplet. METHODS: Enrolled in the study were 26 patients with advanced cancer, most with non-small cell lung cancer. The patients received escalating doses of carboplatin and paclitaxel on day 1 and gemcitabine (30-min infusion) on days 1, 8, and 15 of a 28-day treatment cycle. The doses of each drug ranged from an area under the concentration-time curve (AUC) of 5 to 6 for carboplatin, 135 to 175 mg/m(2) for paclitaxel, and 300 to 1000 mg/m(2) for gemcitabine. RESULTS: Hematologic toxicity was the most commonly observed toxicity and was dose-limiting. During the first cycle at the recommended phase II dose, there were two instances of grade 4 neutropenia and one instance of grade 4 thrombocytopenia among six patients, none of which was dose-limiting. Cumulative hematologic toxicity emerged in subsequent cycles. Non-hematologic toxicities were mild. Five patients, all with previously untreated non-small-cell lung cancer (NSCLC), had a partial response. Nine patients with NSCLC or upper gastrointestinal malignancies experienced stable disease. CONCLUSIONS: Based on significant neutropenia and thrombocytopenia, the regimen recommended for further study consists of carboplatin AUC 5, paclitaxel 175 mg/m(2), and gemcitabine 1000 mg/m(2) on a 28-day cycle. The antitumor activity noted suggests that further investigation of this well-tolerated combination in specific tumor types, especially NSCLC, is warranted.

Adult↗

PubMed2003

A low molecular weight antioxidant decreases weight and lowers tumor incidence.

Stable free radical nitroxides are potent antioxidants possessing superoxide dismutase- and catalase-mimetic activity that protect cells and animals against a variety of oxidative insults. Tempol, as a representative nitroxide, was evaluated for its influence on weight maintenance and spontaneous tumor incidence in C3H mice. Tempol administered in either the drinking water or food did not show any untoward effects and prevented animals from becoming obese. Tempol-treated animals' leptin levels were reduced. Long-term treatment with Tempol significantly decreased tumorigenesis when compared to controls (10 vs. 40%, respectively). Selected tissues from Tempol-treated animals exhibited elevated levels of mitochrondrial uncoupling protein-2 (UCP-2) and HSP70. The present data suggest that nitroxides upregulate UCP-2, obviate weight gain, and decrease age-related spontaneous tumor incidence. As a class, nitroxides may provide overall health benefits by contributing to decreased obesity and tumor incidence.

Animals↗

PubMed2003

A phase I study of Foscan-mediated photodynamic therapy and surgery in patients with mesothelioma.

BACKGROUND: Photodynamic therapy (PDT) is a light-based cancer treatment that, in the correct setting, can be delivered intraoperatively as an adjuvant therapy. A phase I clinical trial combining surgical debulking with Foscan-mediated PDT was performed in patients with malignant pleural mesothelioma. The purpose of the study was to define the toxicities and to determine the maximally tolerated dose (MTD) of Foscan-mediated PDT. METHODS: A total of 26 patients completed treatment. Tumor debulking was accomplished with either an extrapleural pneumonectomy (7 patients) or a lung-sparing pleurectomy-decortication (19 patients). Patients were injected with Foscan before surgery, and 652 nm light was delivered intraoperatively after completion of surgical debulking. Four light sensors were placed in the chest, allowing delivery of light to a uniform measured dose throughout the hemithorax. RESULTS: Four dose levels were explored. The MTD was 0.1 mg/kg of Foscan injected 6 days before surgery in combination with 10 J x cm(-2) 652 nm light. Dose limiting toxicity at the next higher dose was a systemic capillary leak syndrome leading to death in 2 of 3 patients treated at that dose. Other PDT-related toxicities included wound burns and skin photosensitivity. In all, 14 patients were treated at the MTD without significant complications. CONCLUSIONS: Foscan-mediated PDT can be safely combined with surgery at the established MTD. Unlike most other surgery-based multimodal treatments for mesothelioma, Foscan-mediated PDT affords the option, in selected patients, of accomplishing tumor debulking with a lung-sparing procedure rather than an extrapleural pneumonectomy. A phase II study is warranted.

Aged↗

PubMed2003

Correlation of in vivo photosensitizer fluorescence and photodynamic-therapy-induced depth of necrosis in a murine tumor model.

We compared light-induced fluorescence (LIF) to nominal injected drug dose for predicting the depth of necrosis response to photodynamic therapy (PDT) in a murine tumor model. Mice were implanted with radiation-induced fibrosarcoma (RIF) and were injected with 0, 5, or 10 mg/kg Photofrin. 630-nm light (30 J/cm(2), 75 mW/cm(2)) was delivered to the tumor after 24 hours. Fluorescence emission (lambda(excitation)=545 nm, lambda( emission)=628 nm) from the tumor was measured. The LIF data had less scatter than injected drug dose, and was found to be at least as good as an injected drug dose for predicting the depth of necrosis after PDT. Our observations provide further evidence that fluorescence spectroscopy can be used to quantify tissue photosensitizer uptake and to predict PDT tissue damage.

Animals↗

PubMed2003

Intraperitoneal photodynamic therapy causes a capillary-leak syndrome.

BACKGROUND: In patients undergoing intraperitoneal (IP) photodynamic therapy (PDT), the combination of aggressive surgical debulking and light therapy causes an apparent systemic capillary-leak syndrome that necessitates significant intensive care unit (ICU) management after surgery. METHODS: From May 1997 to May 2001, 65 patients underwent surgical debulking and PDT as part of an ongoing phase II trial for disseminated IP cancer. Perioperative data were reviewed retrospectively, and statistical analyses were performed to determine whether any identifiable factors were associated with the need for mechanical ventilation for longer than 1 day and with the occurrence of postoperative complications. RESULTS: Forty-three women and 22 men (mean age, 49 years) were treated. Operative time averaged 9.8 hours, and mean estimated blood loss was 1450 mL. The mean crystalloid requirement for the first 48 hours after surgery was 29.3 L, and 49 patients required blood products. Twenty-four patients were intubated for longer than 24 hours, with a mean of 8.3 days for those intubated longer than 1 day. The median ICU stay was 4 days. Overall, 110 complications developed in 45 (69%) of the 65 patients. Significant complications included 6 patients with acute respiratory distress syndrome, 28 patients with infectious complications, and 4 patients with anastomotic complications. Statistical analyses revealed that surgery-related factors were significantly associated with these complication outcomes. CONCLUSIONS: Patients who undergo surgical debulking and IP PDT develop a significant capillary-leak syndrome after surgery that necessitates massive volume resuscitation, careful ICU monitoring, and, frequently, prolonged ventilatory support.

Adult↗

PubMed2003

In vivo optical properties of normal canine prostate at 732 nm using motexafin lutetium-mediated photodynamic therapy.

The optical properties (absorption [mu(a)], transport scattering [mu('s)] and effective attenuation [mu(eff)] coefficients) of normal canine prostate were measured in vivo using interstitial isotropic detectors. Measurements were made at 732 nm before, during and after motexafin lutetium (MLu)-mediated photodynamic therapy (PDT). They were derived by applying the diffusion theory to the in vivo peak fluence rates measured at several distances (3, 6, 9, 12 and 15 mm) from the central axis of a 2.5 cm cylindrical diffusing fiber (CDF). Mu(a) and mu('s) varied between 0.03-0.58 and 1.0-20 cm(-1), respectively. Mu(a) was proportional to the concentration of MLu.Mu(eff) varied between 0.33 and 4.9 cm(-1) (mean 1.3 +/- 1.1 cm(-1)), corresponding to an optical penetration depth (8 = 1/(mu(eff)) of 0.5-3 cm (mean 1.3 +/- 0.8 cm). The mean light fluence rate at 0.5 cm from the CDF was 126 +/- 48 mW/cm2 (N = 22) when the total power from the fiber was 375 mW (150 mW/cm). This study showed significant inter- and intraprostatic differences in the optical properties, suggesting that a real-time dosimetry measurement and feedback system for monitoring light fluences during treatment should be advocated for future PDT studies. However, no significant changes were observed before, during and after PDT within a single treatment site.

Animals↗

PubMed2003

Elevated serum cytokine levels in mesothelioma patients who have undergone pleurectomy or extrapleural pneumonectomy and adjuvant intraoperative photodynamic therapy.

Patients treated on a Phase-I clinical trial of photodynamic therapy (PDT) developed a systemic capillary leak syndrome that constituted the dose-limiting toxicity. We examined serum samples from patients treated at the maximally tolerated dose level for evidence of a systemic, cytokine-mediated inflammatory response. Patients underwent pleurectomy or extrapleural pneumonectomy (EPP) followed by intraoperative PDT of the thorax using Foscan at a dose of 0.1 mg/kg 6 days before surgery and 652 nm red light at a dose of 10 J/cm2. Levels of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, IL-8, IL-10 and IL-12 were assayed before Foscan administration; after anesthetic induction, surgical resection and light delivery; in postoperative recovery and the day after the surgery. Of the analyzed patients, eight underwent a pleurectomy and one an EPP followed by PDT. IFN-gamma, TNF-alpha and IL-12 showed no elevation, but IL-1beta, IL-6, IL-8 and IL-10 levels were elevated after surgery and PDT. IL-1beta showed a statistically significant variation from baseline after surgery and IL-6, after PDT. The results suggest a systemically mediated inflammatory response resulting from thoracic surgery followed by PDT. Further investigation of specific mechanisms is warranted.

Adult↗

PubMed2003

Protection against Adriamycin cytotoxicity and inhibition of DNA topoisomerase II activity by 3,4-dihydroxybenzoic acid.

The mechanism of Adriamycin (ADR) induced cytotoxicity is not completely understood. While a variety of mechanisms have been proposed, the production of free radicals by redox cycling of the semiquinone has been implicated in cytotoxicity, specifically for cardiotoxicity. To determine whether a scavenger of free radicals would modify the cytotoxicity of ADR, the benzoic acid derivative 3,4-dihydroxybenzoic acid (DHB) was investigated for its ability to protect against ADR-induced cytotoxicity and DNA double strand breaks in Chinese hamster V79 cells. V79 cells were treated with ADR, or its non-redox cycling analog iminodaunomycin, in the presence or absence of DHB. DHB provided significant protection (dose-modifying factor greater than 2.5 for ADR, and nearly 2 for iminodaunomycin) and also caused a dose-dependent decrease in DNA double strand breaks as measured by pulsed field gel electrophoresis. Assays of topoisomerase II activity showed that DHB inhibited topoisomerase II in a concentration-dependent manner, but did not inhibit topoisomerase I. Another non-toxic topoisomerase II inhibitor, the radioprotector WR-1065, also protected against ADR-induced cytotoxicity. These data identify DHB as a non-toxic inhibitor of DNA topoisomerase II and suggest that much of the cytotoxicity of ADR in actively growing V79 cells is due to mechanisms other than redox cycling by the semiquinone.

Animals↗

PubMed2002

In vivo reflectance measurement of optical properties, blood oxygenation and motexafin lutetium uptake in canine large bowels, kidneys and prostates.

Motexafin lutetium (MLu) is a second-generation photosensitizer for photodynamic therapy (PDT) of cancer. We have developed and applied a diffuse optical reflectance spectrometer for in vivo measurement of MLu uptake, optical properties, haemoglobin concentration and haemoglobin oxygen saturation in normal canine large bowels, kidneys and prostates. The probe consists of a broadband fibre-optic-coupled light source and detector fibres placed at various distances from the source fibre to collect reflected light. An analysis based on the diffusion approximation of the photon transport equation was used to recover tissue optical properties from the reflectance measurements. The instrumentation and analysis methods were validated using measurements from homogeneous, highly scattering phantoms with known MLu concentrations. The same techniques were then used to estimate chromophore concentrations of normal canine large bowels, kidneys and prostates. We estimated (mean (standard deviation)) total haemoglobin concentrations of 119 (25), 340 (92) and 51 (11) microM in the large bowels, kidneys and prostates of four dogs, respectively; tissue blood oxygen saturations in these same organs were 75 (15), 76 (21) and 74 (16) per cent, respectively. Tissue MLu concentrations (mg l(-1)) were estimated from data taken 3.5 h after injection of a 2 mg kg(-1) injected dose; data from three dogs gave concentrations of 2.4 (0.4) in large bowels, 6.8 (1.3) in kidneys and 2.2 (1.1) in prostates. The reduced scattering coefficients, mu's, estimated for large bowels, kidneys and prostates at 730 nm were, respectively: 10.1 (1.3), 19.6 (4.0) and 12.7 (0.6) cm(-1). We observed significant variability in MLu uptake, tissue scattering and haemoglobin concentration between organs and even between the same organ in different dogs. This class of in situ optical property measurement may be desirable to individualize PDT drug and light delivery.

Algorithms↗

PubMed2002

In vivo light dosimetry for motexafin lutetium-mediated PDT of recurrent breast cancer.

BACKGROUND AND OBJECTIVES: To measure the fluence at tissue surface for patients in our Phase II clinical trial of motexafin lutetium (MLu)-mediated chest wall photodynamic therapy for recurrent breast carcinoma and to compare it to the calculated irradiance. STUDY DESIGN/MATERIALS AND METHODS: The spatial and time dependence of light fluence (rate) was monitored in vivo on the chest wall surface using isotropic detectors in five patients. Patients were given MLu either 4 mg/kg with light at 18 hours or 5 mg/kg with light at 24 hours using an irradiance of 150 J/cm(2) at 730 nm, with an incident fluence rate of 75 mW/cm(2). The ratio of fluence rate to the incident fluence rate was determined at the center of the treatment field. This ratio was used to estimate the effective attenuation coefficient, mu (eff). RESULTS: The mean and standard deviation of the ratio for all patients was 1.6 +/- 0.2. The corresponding range of mu (eff) was between 0.87 and 2.1 cm(-1), assuming reduced scattering coefficient, mu (s) = 4 cm(-1). CONCLUSIONS: A conversion factor was determined to convert the irradiance to fluence rate on the tissue surface. However, the fluence (or the ratio) on patient surface varied by 70% due to the heterogeneity of optical properties. This supports the use of real-time in vivo dosimetry during photodynamic therapy.

Adult↗

PubMed2002

Rates of unconventional medical therapy use in patients with prostate cancer: standard history versus directed questions.

OBJECTIVES: The use of unconventional medical therapies (UMTs) in the general population has increased dramatically in the past decade. Studies have estimated that 9% to 64% of patients with cancer use UMTs, and many do not disclose this information to their physicians. This study was designed to evaluate the rates of UMT use by patients with prostate cancer revealed by standard versus directed questioning and to identify demographic markers that may predict use. METHODS: A prospective study of 287 consecutive patients with cancer presenting to the Department of Radiation Oncology was performed. The prostate cancer population was 29% (84 of 287) of the total cancer patient population. Each patient underwent the standard history interview, including questions regarding prescription and over-the-counter medication. At the completion of the standard history interview, patients were then asked a set of directed questions regarding the use of UMTs. RESULTS: Of the 84 patients with prostate cancer, 31 (37%) used unconventional therapies. The standard history revealed that 6 (19%) of 31 used UMTs, and directed questioning revealed an additional 25 patients (81%) used UMTs in the study population (P <0.001). Of those using UMTs, 65% used megavitamins, 49% used herbal remedies, 13% used meditation or guided imagery, and 20% used nonherbal natural supplements. CONCLUSIONS: UMT use is prevalent among patients with prostate cancer. Some of these treatments may have a potential biologic impact on tumor behavior, therapeutic endpoints, and measured prostate-specific antigen values. The use of directed questioning during the patient evaluation significantly increases the physician's ability to identify patients with prostate cancer using UMTs.

Antioxidants↗

PubMed2002

Farnesyltransferase inhibitors as radiation sensitizers.

Activation of Ras, by mutation, overexpression, or by signaling through tyrosine kinase receptors, is associated with radioresistance. Thus, therapies that inhibit Ras function could be an effective means to radiosensitize selected types of solid tumors. Inhibition of Ras prenylation using a variety of farnesyltransferase inhibitors resulted in radiosensitization of tumor cells that expressed activated Ras, both in vitro and in xenograft models. Farnesyltransferase inhibitor treatment could also inhibit tumor regrowth following irradiation of mice bearing T24 tumor xenografts that express activated Ras. In a phase I trial of the farnesyltransferase inhibitor L-778-123 and radiotherapy in patients with locally advanced head and neck cancer and non-small cell lung cancer, a high response rate was observed coupled with a mild toxicity profile. Additional clinical trials should shed light on the potential of this and other farnesyltransferase inhibitors to serve as radiosensitizers and may identify molecular markers that could predict a response to these agents.

Alkyl and Aryl Transferases↗

PubMed2002

A Phase I trial of the farnesyltransferase inhibitor L-778,123 and radiotherapy for locally advanced lung and head and neck cancer.

PURPOSE: Preclinical data have demonstrated that farnesyltransferaseinhibitors (FTIs) are radiation sensitizers in selected cell lines. The objective of this Phase I trial was to determine the maximally tolerated dose of the FTI L-778,123 in combination with radiotherapy in non-small cell lung cancer (NSCLC) and head and neck cancer (HNC). EXPERIMENTAL DESIGN: L-778,123 was given by continuous i.v. infusion and dose escalated in conjunction with standard radiotherapy. The presence of a ras mutation was not required for study entry. RESULTS: Nine patients (six NSCLC patients and three HNC patients) were enrolled on two dose levels of FTI. No dose-limiting toxicities were observed at the first dose level of 280 mg/m2/day during weeks 1, 2, 4, and 5 of radiotherapy. One episode of dose-limiting toxicity, grade IV neutropenia, was observed in one of three patients treated at 560 mg/m2/day during weeks 1, 2, 4, 5, and 7. No episodes of dose-limiting mucositis, esophagitis, or pneumonitis were observed. Of the four patients with NSCLC with evaluable disease, three patients had a complete response to treatment and one patient had a partial response. A complete clinical response to treatment was observed in two patients with HNC. In vitro studies in tumor cells obtained from a NSCLC patient on this trial showed radiosensitization with FTI and that tumor cells accumulated in G2-M after L-778,123 treatment. CONCLUSIONS: The combination of L-778,123 and radiotherapy at dose level 1 is associated with acceptable toxicity. Local responses have been observed in four NSCLC patients without a clear increase in radiotherapy-associated toxicities.

Adult↗

PubMedDate not supplied

Pathological response to preoperative chemoradiation worsens with anemia in non-small cell lung cancer patients.

PURPOSE: Positive links between hemoglobin level and therapeutic tumor response are well documented in carcinoma of the cervix and the head and neck, but little evidence of such a link exists for lung cancer. We analyzed our series of patients treated with preoperative chemoradiation for stage IIIA non-small cell lung carcinoma. PATIENTS AND METHODS: Between June 1992 and February 2000, 41 consecutive patients with clinical stage IIIA (N2, documented by mediastinoscopy or another invasive procedure) non-small cell lung carcinoma received preoperative-intent chemoradiation. The median preoperative radiation dose was 48.6 Gy, and all patients received cisplatin- or paclitaxel-based chemotherapy. Response was graded on a four point scale: (1) progressive disease before surgery and/or technically inoperable; (2) stable disease with resection performed, but specimen containing > 50% viable tumor; (3) partial response with specimen containing < 50% tumor; and (4) complete response or near-complete response: RO resection with no residual carcinoma or pT1NO with only microscopic residual foci. Pretreatment hemoglobin values were correlated with pathological outcome using ANOVA and the non-parametric test for trend across ordered groups. RESULTS: The mean hemoglobin level for groups 1 through 4 was 11.8, 12.1, 12.5, and 13.2 respectively, and the association was statistically significant. If the analysis was limited to patients actually undergoing surgery (eliminating group 1), the association remained significant. The nonparametric test for trend across ordered groups was also significant with and without group 1. DISCUSSION: Our analysis supports the hypothesis that response to chemoradiation of non-small cell lung carcinoma improves with increasing hemoglobin levels.

Adult↗

PubMedDate not supplied

Broadband reflectance measurements of light penetration, blood oxygenation, hemoglobin concentration, and drug concentration in human intraperitoneal tissues before and after photodynamic therapy.

We evaluate Photofrin-mediated photodynamic therapy (PDT) in a phase 2 clinical trial as an adjuvant to surgery to treat peritoneal carcinomatosis. We extract tissue optical [reduced scattering (mu(s)'), absorption (mu(a)), and attenuation coefficients (mu(eff))] and physiological [blood oxygen saturation (%S(t)O2), total hemoglobin concentration (THC), and photosensitizer concentration (c(Photofrin))] properties in 12 patients using a diffuse reflectance instrument and algorithms based on the diffusion equation. Before PDT, in normal intraperitoneal tissues %S(t)O2 and THC ranged between 32 to 100% and 19 to 263 microM, respectively; corresponding data from tumor tissues ranged between 11 to 44% and 61 to 224 microM. Tumor %S(t)O2 is significantly lower than oxygenation of normal intraperitoneal tissues in the same patients. The mean (+/-standard error of mean) penetration depth (delta) in millimeters at 630 nm is 4.8(+/-0.6) for small bowel, 5.2 (+/-0.67) for large bowel, 3.39(+/-0.29) for peritoneum, 5.19(+/-1.4) for skin, 1.0(+/-0.1) for liver, and 3.02(+/-0.66) for tumor. c(Photofrin) in micromolars is 4.9(+/-2.3) for small bowel, 4.8(+/-2.3) for large bowel, 3.0 (+/-1.0) for peritoneum, 2.5(+/-0.9) for skin, and 7.4(+/-2.8) for tumor. In all tissues examined, mean c(Photofrin) tends to decrease after PDT, perhaps due to photobleaching. These results provide benchmark in-vivo tissue optical property data, and demonstrate the feasibility of in-situ measurements during clinical PDT treatments.

Algorithms↗