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180 results on '"Dimofte, Andreea"'

8. Optimizing biophotonics and immune response research: a proposal for in vivo dose escalation and light dosimetry analysis in porcine models

Author

Sourvanos, Dennis, primary, Zhu, Timothy, additional, Dimofte, Andreea, additional, Busch, Theresa, additional, Yang, Weibing, additional, Burrell, Justin, additional, Neiva, Rodrigo, additional, Schoenbaum, Todd, additional, Chen, Zhaoxu, additional, Ko, Kang, additional, and Fiorellini, Joseph, additional

Published
2024
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9. Experimental Indications of Electro-Gravity

Author

Datta, T., Yin, Ming, Dimofte, Andreea, Bleiweiss, M. C., and Cai, Zhihua

Subjects
Physics - General Physics
Abstract

Recent results from our on going experimental investigation of the influence of space dependant electric fields on the weight of test particles are reported. Test particles were gold coated metal spheres of same size but of different masses. Data collected from a number of runs over several years continue to indicate an intriguing effect. For experimental parameters in question this effect is manifested as a ppm level sample mass dependent force additional to expected electrostatic forces. A force that is proportional to mass is the unique signature of gravity furthermore it is non-zero only when the field is applied; hence these observations may be further evidence in support of electro-gravity., Comment: 17 pages including 1 table and 4 figures with captions

Published
2005

11. Clinical PDT dose dosimetry for pleural Photofrin-mediated photodynamic therapy.

Author

Hongjing Sun, Yihong Ong, Weibing Yang, Sourvanos, Dennis, Dimofte, Andreea, Busch, Theresa M., Singhal, Sunil, Cengel, Keith A., and Zhu, Timothy C.

Subjects
MEDICAL dosimetry, PHOTODYNAMIC therapy, PHOTOMETRY, TREATMENT effectiveness, CANCER treatment, THERMOLUMINESCENCE dosimetry
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 µM, with a median concentration of 4.47 µM. The average PDT dose for all 78 sites is 493.17 µMJ/cm², with a median dose of 442.79 µMJ/cm². 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. [ABSTRACT FROM AUTHOR]

Published
2024
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18. Evaluation of Light Fluence Distribution Using an IR Navigation System for HPPH‐mediated Pleural Photodynamic Therapy (pPDT)

Author

Zhu, Timothy C., primary, Ong, Yihong, additional, Kim, Michele M., additional, Liang, Xing, additional, Finlay, Jarod C., additional, Dimofte, Andreea, additional, Simone, Charles B., additional, Friedberg, Joseph S., additional, Busch, Theresa M., additional, Glatstein, Eli, additional, and Cengel, Keith A., additional

Published
2020
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22. Proton beam versus photon beam dose to the heart and left anterior descending artery for left-sided breast cancer

Author

Lin, Lilie L., Vennarini, Sabina, Dimofte, Andreea, Ravanelli, Daniele, Shillington, Katie, Batra, Sonny, Tochner, Zelig, Both, Stefan, and Freedman, Gary

Abstract

Purpose. The purpose of this study was to compare the dose to heart, left anterior descending (LAD) artery and lung between proton and photon beam irradiation for left-sided early stage breast cancer. Material and methods. Ten women with early stage left-sided breast cancer were treated with breast conserving surgery and radiation. Whole breast radiation was delivered for actual treatment via a tangential technique with deep inspiration breath hold (DIBH) utilizing inverse planned intensity-modulated radiation therapy (IMRT). Each patient was replanned on an Institutional Review Board (IRB)-approved prospective study using en face proton beam radiation with both uniform scanning (US) and pencil beam scanning (PBS) techniques. Results. Both PBS (0.011 Gy) and US (0.009 Gy) proton plans resulted in a significantly lower mean heart dose compared to IMRT (1.612 Gy) (p < 0.05 for PBS vs. IMRT and US vs. IMRT). The Dmean, Dmin, Dmax, and D0.2cm3 of the LAD with either proton technique were significantly lower (p = 0.005) compared to IMRT. Both US and PBS reduced the mean dose to the lungs compared to IMRT. The coverage of the breast planning target volume was comparable between photon and proton plans. Conclusions. The dose to whole heart was relatively low in this study of patients treated under conditions of DIBH. However, proton beam radiation was associated with lower minimum, maximum, and dose to 0.2 cm3 of the LAD, which is the critical structure for late radiation therapy effects, compared to even the most optimized photon beam plan with DIBH and IMRT.

Published
2017
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38. An IR navigation system for pleural PDT

Author

Zhu, Timothy C., primary, Liang, Xing, additional, Kim, Michele M., additional, Finlay, Jarod C., additional, Dimofte, Andreea, additional, Rodriguez, Carmen, additional, Simone, Charles B., additional, Friedberg, Joseph S., additional, and Cengel, Keith A., additional

Published
2015
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41. Integrated light dosimetry system for prostate photodynamic therapy

Author

Jun Li, Dimofte Andreea, Timothy C. Zhu, Jarod C. Finlay, and Xiaodong Zhou

Subjects
Materials science, business.industry, System of measurement, medicine.medical_treatment, Photodynamic therapy, Light delivery, Article, law.invention, medicine.anatomical_structure, Optics, Real-time Control System, law, Prostate, medicine, Dosimetry, Light Dosimetry, business, Beam splitter
Abstract

A light dosimetry system is developed for prostate PDT, which integrates four main components: a light fluence rate calculation engine, an optimization tool for treatment planning, a light delivery system, and an in vivo light fluence rate measurement system. Three-dimensional light fluence rate distribution in a prostate is calculated using a kernel algorithm, which takes into account of heterogeneous optical properties. A Cimmino optimization algorithm is used to optimize the parameters of the cylindrical diffusing fibers (CDFs) to generate uniform PDT dose (or light fluence rate under uniform drug distribution) to cover the heterogeneous prostate. The light delivery system is composed of a 12-channel beamsplitter and the intensities of each channel (i.e., source) are controlled individually by programmable motorized attenuators. Our tests show that the light fluence rate calculation is fast and the accuracy is close to that of a finite-element method model, and the approach that uses the treatment CDFs to determine optical properties, improves the accuracy of light fluence rate prediction. The light delivery system allows real time control of the light source intensities for both PDT dosimetry and PDT light delivery. Integrating the fast light fluence rate calculation, optimization, instant source intensity adjustment, and in vivo light fluence rate measurement, the dosimetry system is suitable for prostate PDT.

Published
2008

47. Real-time treatment feedback guidance of Pleural PDT

Author

Zhu, Timothy C., primary, Kim, Michele M., additional, Liang, Xing, additional, Liu, Baochang, additional, Meo, Julia L., additional, Finlay, Jarod C., additional, Dimofte, Andreea, additional, Rodriguez, Carmen, additional, Simone, Charles, additional, Cengel, Keith, additional, and Friedberg, Joseph, additional

Published
2013
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50. A real-time treatment guidance system for pleural PDT

Author

Zhu, Timothy C., primary, Liang, Xing, additional, Sandell, Julia, additional, Finlay, Jarod C., additional, Dimofte, Andreea, additional, Rodriguez, Carmen, additional, Cengel, Keith, additional, Friedberg, Joseph, additional, Hahn, Stephen M., additional, and Glatstein, Eli, additional

Published
2012
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