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Sun H, Ong Y, Yang W, Sourvanos D, Dimofte A, Busch TM, Singhal S, Cengel KA, Zhu TC. Clinical PDT dose dosimetry for pleural Photofrin-mediated photodynamic therapy. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:018001. [PMID: 38223299 PMCID: PMC10787190 DOI: 10.1117/1.jbo.29.1.018001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/14/2023] [Accepted: 12/21/2023] [Indexed: 01/16/2024]
Abstract
Significance Photodynamic therapy (PDT) is an established cancer treatment utilizing light-activated photosensitizers (PS). Effective treatment hinges on the PDT dose-dependent on PS concentration and light fluence-delivered over time. We introduce an innovative eight-channel PDT dose dosimetry system capable of concurrently measuring light fluence and PS concentration during treatment. Aim We aim to develop and evaluate an eight-channel PDT dose dosimetry system for simultaneous measurement of light fluence and PS concentration. By addressing uncertainties due to tissue variations, the system enhances accurate PDT dosimetry for improved treatment outcomes. Approach The study positions eight isotropic detectors strategically within the pleural cavity before PDT. These detectors are linked to bifurcated fibers, distributing signals to both a photodiode and a spectrometer. Calibration techniques are applied to counter tissue-related variations and improve measurement accuracy. The fluorescence signal is normalized using the measured light fluence, compensating for variations in tissue properties. Measurements were taken in 78 sites in the pleural cavities of 20 patients. Results Observations reveal minimal Photofrin concentration variation during PDT at each site, juxtaposed with significant intra- and inter-patient heterogeneities. Across 78 treated sites in 20 patients, the average Photofrin concentration for all 78 sites is 4.98 μ M , with a median concentration of 4.47 μ M . The average PDT dose for all 78 sites is 493.17 μ MJ / cm 2 , with a median dose of 442.79 μ MJ / cm 2 . A significant variation in PDT doses is observed, with a maximum difference of 3.1 times among all sites within one patient and a maximum difference of 9.8 times across all patients. Conclusions The introduced eight-channel PDT dose dosimetry system serves as a valuable real-time monitoring tool for light fluence and PS concentration during PDT. Its ability to mitigate uncertainties arising from tissue properties enhances dosimetry accuracy, thus optimizing treatment outcomes and bolstering the effectiveness of PDT in cancer therapy.
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Affiliation(s)
- Hongjing Sun
- University of Pennsylvania, Department of Radiation Oncology, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, Department of Bioengineering, Philadelphia, Pennsylvania, United States
| | - Yihong Ong
- University of Pennsylvania, Department of Radiation Oncology, Philadelphia, Pennsylvania, United States
| | - Weibing Yang
- University of Pennsylvania, Department of Radiation Oncology, Philadelphia, Pennsylvania, United States
| | - Dennis Sourvanos
- University of Pennsylvania, School of Dental Medicine, Department of Periodontics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, Schools of Engineering and Dental Medicine, Center for Innovation and Precision Dentistry, Philadelphia, Pennsylvania, United States
| | - Andreea Dimofte
- University of Pennsylvania, Department of Radiation Oncology, Philadelphia, Pennsylvania, United States
| | - Theresa M. Busch
- University of Pennsylvania, Department of Radiation Oncology, Philadelphia, Pennsylvania, United States
| | - Sunil Singhal
- University of Pennsylvania, Department of Surgery, Philadelphia, Pennsylvania, United States
| | - Keith A. Cengel
- University of Pennsylvania, Department of Radiation Oncology, Philadelphia, Pennsylvania, United States
| | - Timothy C. Zhu
- University of Pennsylvania, Department of Radiation Oncology, Philadelphia, Pennsylvania, United States
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Sun H, Yang W, Ong Y, Busch TM, Zhu TC. Fractionated Photofrin-Mediated Photodynamic Therapy Significantly Improves Long-Term Survival. Cancers (Basel) 2023; 15:5682. [PMID: 38067385 PMCID: PMC10705090 DOI: 10.3390/cancers15235682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 11/23/2023] [Accepted: 11/28/2023] [Indexed: 02/12/2024] Open
Abstract
This study investigates the effect of fractionated (two-part) PDT on the long-term local control rate (LCR) using the concentration of reactive oxygen species ([ROS]rx) as a dosimetry quantity. Groups with different fractionation schemes are examined, including a 2 h interval between light delivery sessions to cumulative fluences of 135, 180, and 225 J/cm2. While the total treatment time remains constant within each group, the division of treatment time between the first and second fractionations are explored to assess the impact on long-term survival at 90 days. In all preclinical studies, Photofrin is intravenously administered to mice at a concentration of 5 mg/kg, with an incubation period between 18 and 24 h before the first light delivery session. Fluence rate is fixed at 75 mW/cm2. Treatment ensues via a collimated laser beam, 1 cm in diameter, emitting light at 630 nm. Dosimetric quantities are assessed for all groups along with long-term (90 days) treatment outcomes. This study demonstrated a significant improvement in long-term survival after fractionated treatment schemes compared to single-fraction treatment, with the optimal 90-day survival increasing to 63%, 86%, and 100% vs. 20%, 25%, and 50%, respectively, for the three cumulative fluences. The threshold [ROS]rx for the optimal scheme of fractionated Photofrin-mediated PDT, set at 0.78 mM, is significantly lower than that for the single-fraction PDT, at 1.08 mM.
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Affiliation(s)
- Hongjing Sun
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA; (H.S.); (W.Y.); (T.M.B.)
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Weibing Yang
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA; (H.S.); (W.Y.); (T.M.B.)
| | - Yihong Ong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA; (H.S.); (W.Y.); (T.M.B.)
| | - Theresa M. Busch
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA; (H.S.); (W.Y.); (T.M.B.)
| | - Timothy C. Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA; (H.S.); (W.Y.); (T.M.B.)
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Mathematical modelling for antimicrobial photodynamic therapy mediated by 5-aminolaevulinic acid: An in vitro study. Photodiagnosis Photodyn Ther 2022; 40:103116. [PMID: 36100198 DOI: 10.1016/j.pdpdt.2022.103116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/09/2022] [Accepted: 09/09/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND Antimicrobial photodynamic therapy (aPDT) using aminolaevulinic acid (ALA) is a promising alternative to antibiotic therapy. ALA administration induces protoporphyrin IX (PpIX) accumulation in bacteria, and light excitation of the accumulated PpIX generates singlet oxygen to bacterial toxicity. Several factors, including drug administration and light irradiation conditions, contribute to the antibiotic effect. Such multiple parameters should be determined moderately for effective aPDT in clinical practice. METHODS A mathematical model to predict bacterial dynamics in ALA-aPDT following clinical conditions was constructed. Applying a pharmacokineticspharmacodynamics (PK-PD) approach, which is widely used in antimicrobial drug evaluation, viable bacteria count by defining the bactericidal rate as the concentration of singlet oxygen produced when PpIX in bacteria is irradiated by light. RESULTS The in vitro experimental results of ALA-aPDT for Pseudomonas aeruginosa demonstrated the PK-PD model validity. The killing rate has an upper limit, and the lower power density for a long irradiation time can suppress the viable bacteria number when the light dosages are the same. CONCLUSIONS This study proposed a model of bacterial viability change in ALA-aPDT based on the PK-PD model and confirmed, by in vitro experiments using PA, that the variation of bacterial viability with light-sensitive substance concentration and light irradiation power densities could be expressed. Further validation of the PK-PD model with other gram negative and gram positive strains will be needed.
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Zhu TC, Sun H, Ong YH, Morales RH, Dimofte A, Busch T, Singhal S, Cengel KA. Real-time PDT Dose Dosimetry for Pleural Photodynamic Therapy. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2022; 11940:1194002. [PMID: 35573026 PMCID: PMC9104001 DOI: 10.1117/12.2612188] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
PDT dose is the product of the photosensitizer concentration and the light fluence in the target tissue. For improved dosimetry during plural photodynamic therapy (PDT), an eight-channel PDT dose dosimeter was developed to measure both the light fluence and the photosensitizer concentration simultaneously from eight different sites in the pleural cavity during PDT. An isotropic detector with bifurcated fibers was used for each channel to ensure detected light was split equally to the photodiode and spectrometer. The light fluence rate distribution is monitored using an IR navigation system. The navigation system allows 2D light fluence mapping throughout the whole pleural cavity rather than just the selected points. The fluorescence signal is normalized by the light fluence measured at treatment wavelength. We have shown that the absolute photosensitizer concentration can be obtained by applying optical properties correction and linear spectral fitting to the measured fluorescence data. The detection limit and the optical property correction factor of each channel were determined and validated using tissue-simulating phantoms with known varying concentration of Photofrin. Tissue optical properties are determined using an absorption spectroscopy probe immediately before PDT at the same sites. The combination of 8-channel PDT dosimeter system and IR navigation system, which can calculate light fluence rate in the pleural cavity in real-time, providing a mean to determine the distribution of PDT dose on the entire pleural cavity to investigate the heterogeneity of PDT dose on the pleural cavity.
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Affiliation(s)
- Timothy C. Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hongjing Sun
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi-Hong Ong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ryan Hall Morales
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Andreea Dimofte
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Theresa Busch
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Sunil Singhal
- Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Keith A. Cengel
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
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Sheng T, Ong Y, Busch TM, Zhu TC. Reactive oxygen species explicit dosimetry to predict local tumor growth for Photofrin-mediated photodynamic therapy. BIOMEDICAL OPTICS EXPRESS 2020; 11:4586-4601. [PMID: 32923066 PMCID: PMC7449736 DOI: 10.1364/boe.393524] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/23/2020] [Accepted: 07/07/2020] [Indexed: 05/31/2023]
Abstract
Although photodynamic therapy (PDT) is an established modality for cancer treatment, current dosimetric quantities, such as light fluence and PDT dose, do not account for the differences in PDT oxygen consumption for different fluence rates (ϕ). A macroscopic model was adopted to calculate reactive oxygen species concentration ([ROS]rx) to predict Photofrin-PDT outcome in mice bearing radiation-induced fibrosarcoma (RIF) tumors. Singlet oxygen is the primary cytotoxic species for ROS, which is responsible for cell death in type II PDT, although other type I ROS is included in the parameters used in our model. Using a combination of fluences (50-250 J∕cm2) and ϕ (75 or 150 mW∕cm2), tumor regrowth rate, k, was determined for each condition by fitting the tumor volume versus time to V0 *exp(k*t). Treatment was delivered with a collimated laser beam of 1 cm diameter at 630 nm. Explicit dosimetry of light fluence rate on tissue surface, tissue oxygen concentration, tissue optical properties, and Photofrin concentration were performed. Light fluence rate at 3 mm depth (ϕ 3mm) was determined for the treatment volume based on Monte-Carlo simulations and measured tissue optical properties. Initial tissue oxygenation [3 O 2]0 was measured by an Oxylite oxygen probe before PDT and used to calculate [ROS]rx,calc. This value was compared to [ROS]rx,meas as calculated with the entire tissue oxygen spectrum [3 O 2](t), measured over the duration of light delivery for PDT. Cure index, CI = 1-k/kctr , for tumor growth up to 14 days after PDT was predicted by four dose metrics: light fluence, PDT dose, and [ROS]rx,calc, and [ROS]rx,meas. PDT dose was defined as the product of the time-integral of photosensitizer concentration and ϕ at a 3 mm tumor depth. These studies show that [ROS]rx,meas best correlates with CI and is an effective dosimetric quantity that can predict treatment outcome.
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