Filter by type:

Sort by date:

1.  Effects of LED-Based Photodynamic Therapy using Red and Blue Lights, with Natural Hydrophobic Photosensitizers on Human Glioma Cell Line

Jamali Z, Hejazi SM, Ebrahimi SM, Moradi-Sardareh H, Paknejad M
Journal Paper
Photodiagnosis Photodyn Ther. 2017 Nov 7. pii: S1572-1000(17)30341-1. doi: 10.1016/j.pdpdt.2017.11.002.
Abstract
Photodynamic therapy (PDT) has received high attention in cancer treatment due to its minimal side effects, specific cancer-targeting, non-invasion and low cost. It utilizes a specific group of anti-cancer drugs called photosensitizers (PS), which can be only activated under a certain wavelength light illumination and kills cancer cells. To screen the potential of PS and setup of PDT treatment protocol, it is essential to assess the PDT efficacy in vitro. In this study, a light-emitting diode- (LED-) based illumination system at two wavelengths (red & blue) with homogeneous and stable irradiation, and constant temperature conditions in 96-well plates was provided. The photodynamic effect of curcumin (CUR) and methyl ester of 5-aminolevulinic acid (MAL) using LED light on human glioma cell line was investigated. The obtained results indicate that this homemade LED-based illumination system is a favorable light source for in vitro PDT in 96-well plates. The PDT using CUR and MAL was efficient at final concentrations of 25μM and 2mM, and light doses of 60J/cm2 and 40J/cm2 respectively. The blue PDT efficiency was dependent on the light and PS doses. MAL-PDT and CUR-PDT using blue LED significantly decreased cell viability in the treatment groups compared with control groups. Furthermore, MAL-PDT using blue LEDs was more effective in comparison with conventional red LEDs on the human glioma cell line.
Keywords: Photodynamic therapy, Methyl ester of 5-aminolevulinic acid, Curcumin, Human glioma cell line

2.  Optimization of optical arrangement of fluorescent molecular imaging to improve the accuracy of reconstruction method by calculating the jacobian matrix

A.Ebrahimpoor, M.Hejazi
Journal Paper
Laser in medicine, In press

3.  Fluorescence Plannar Imaging Fluovison

Invention
US patent and CE in progress

4.  Fast multislice fluorescence molecular tomography using sparsity-inducing regularization

M.Hejazi, S.Sarkar, Z.Darezershki
Journal Paper
J. Biomed. Opt. 2016, 21(2) 026012 doi: 10.1117/1.JBO.21.2.026012

Abstract:

Fluorescence molecular tomography (FMT) is a rapidly growing imaging method that facilitates the recovery of small fluorescent targets within biological tissue. The major challenge facing the FMT reconstruction method is the ill-posed nature of the inverse problem. In order to overcome this problem, the acquisition of large FMT datasets and the utilization of a fast FMT reconstruction algorithm with sparsity regularization have been suggested recently. Therefore, the use of a joint L1/total-variation (TV) regularization as a means of solving the ill-posed FMT inverse problem is proposed. A comparative quantified analysis of regularization methods based on L1-norm and TV are performed using simulated datasets, and the results show that the fast composite splitting algorithm regularization method can ensure the accuracy and robustness of the FMT reconstruction. The feasibility of the proposed method is evaluated in an in vivo scenario for the subcutaneous implantation of a fluorescent-dye-filled capillary tube in a mouse, and also using hybrid FMT and x-ray computed tomography data. The results show that the proposed regularization overcomes the difficulties created by the ill-posed inverse problem.

5.  Fluorescence molecular tomography multislice imaging system

Invention
US patent & CE from ESM Italy

6.  Accuracy increment of image reconstruction method in FMT using regularization matrices based on structural information

M. Hejazi
Journal Paper
Laser in medicine, 2015

7.  Design and evaluation of integrated optical setup for interstitial photodynamic therapy using Monte-Carlo simulation

Alireza Talkhabi, Marjaneh Hejazi, Reza Fekrazad
Journal Paper
Lasers in Medicine 2015

8.  Design and evaluation of integrated optical setup for photodynamic therapy using Monte Carlo simulation and fluorescence molecular tomography

A.Talkhabi, M.Hejazi, R.Fekrazad
Journal Paper
2015

9.  Design and implementation of optical spectrum reconstruction algorithm in free space geometry using finite element method to determine the concentration of tissue hemoglobin in small animal

H.Hashemi, M.Hejazi, A.Ahmadbeighi
Journal Paper
Laser in medicine, 2015

10.  Medical Physics for Medical & Dentistry Students

MA Oghabian, MJ Abolhassani, S Sarkar, M hejazi
Book
Royan Pzhouh Publication, 2015 | ISBN-13: 8966308600978

11.  Evaluation effect of light leakage and sensitivity on point spread function of intraoperative fluorescence imaging system in a tissue-like phantom

M.Ebrahimi, M.Hejazi
Journal Paper
Lasers in Medicine, 10(1), 2014

12.  Optimization of optical arrangement for fluorescent molecular imaging to improve the accuracy of the reconstruction by calculating the jacobian matrix

Anita Ebrahimpoor, Marjaneh Hejazi, Bahador Makkiabadi
Journal Paper
Lasers in Medicine 2014

13.  Resolution improvement of multispectral fluorescent molecular tomography images using linear unmixing algorithm

P. Mirzaghavami, M.Hejazi
Journal Paper
Lasers in Medicine, 10(1),2014

14.  Development and evaluation of a multislice fluorescence molecular tomography using finite element method

M.Hejazi, S Sarkar, H Mohammadreza, T Jahanfar, M Karimi
Journal Paper
Proc. SPIE 8799, Diffuse Optical Imaging IV, 87990R (14 June 2013)

Abstract:

Fluorescence molecular tomography is a novel approach that allows small animal imaging for early detection of cancer. However, challenges still remain in the improvement of the FMT software and hardware. In this work, a multislice FMT imaging system was developed and a finite element software with the modified calibration method was adapted to the geometry system. Phantom experiments are performed to verify the feasibility of the proposed method. The results demonstrate that the spatial resolution of the imaging system is less than 0.5mm and acquisition data time 30 minutes. In conclusion, The FMT system is capable to quantify 3D dye distribution using the well documented finite element software.

15.  Development of a semi-automatic method for quantifying the area of the autofluorescence distribution in Fundus autofluorescence images of patient with CME

M.Hejazi
Journal Paper
2013

16.  In vitro multispectral fluoresance imaging using linear unmixing in reflectance mode

E.Najafzadeh, M.Hejazi
Journal Paper
Iranian Journal of Medical Physics, 2012

17.  Solve The Forward Problems By Green FunctionIn New Fluorescence Molecular Tomography Imaging System

T.Jahanfar, M.Hejazi
Journal Paper
WC IFMBE Proceedings 2012

18.  Determination of experimental Tumor Volume of a mouse using optical imaging system in different processing stages

M.Hosseni, M.Hejazi
Journal Paper
Lasers in Medicine, 2011; 8 (1)

19.  Simulation of Heat distribution and thermal damage patterns of diode hair

L.Ataie-Fashtami, A. Shirkavand,S.Sarkar, M.R.Alinaghizadeh, M.Hejazi
Journal Paper
Photomedicine Laser Surgery. 2011 Jul;29(7):509-15

20.  A Modified Semiautomatic Method for Measurement of Hyperfluorescence Area in Fluorescein Angiography

K.Ghasemi,H.Mohammadreza, M.Hejazi
Journal Paper
Iranian Journal of Ophthalmology 22(4),73-79, 2010

21.  Improving the accuracy of a solid spherical source radius and depth estimation using the diffusion equation in fluorescence reflectance mode

M. Hejazi, F Stuker, D Vats, and M Rudin
Journal Paper
Biomedical Engineering online,2010, 9:28

Abstract:

BACKGROUND: Non-invasive planar fluorescence reflectance imaging (FRI) is used for accessing physiological and molecular processes in biological tissue. This method is efficiently used to detect superficial fluorescent inclusions. FRI is based on recording the spatial radiance distribution (SRD) at the surface of a sample. SRD provides information for measuring structural parameters of a fluorescent source (such as radius and depth). The aim of this article is to estimate the depth and radius of the source distribution from SRD, measured at the sample surface. For this reason, a theoretical expression for the SRD at the surface of a turbid sample arising from a spherical light source embedded in the sample, was derived using a steady-state solution of the diffusion equation with an appropriate boundary condition.
METHODS:The SRD was approximated by solving the diffusion equation in an infinite homogeneous medium with solid spherical sources in cylindrical geometry. Theoretical predications were verified by experiments with fluorescent sources of radius 2-6 mm embedded at depths of 2-4 mm in a tissue-like phantom.
RESULTS:The experimental data were compared with the theoretical values which shows that the root mean square (RMS) error in depth measurement for nominal depth values d = 2, 2.5, 3, 3.5, 4 mm amounted to 17%, 5%, 2%, 1% and 5% respectively. Therefore, the average error in depth estimation was < or = 4% for depths larger than the photon mean free path.
CONCLUSIONS:An algorithm is proposed that allows estimation of the location and radius of a spherical source in a homogeneous tissue-like phantom by accounting for anisotropic light scattering effect using FRI modality. Surface SRD measurement enabled accurate estimates of fluorescent depth and radius in FRI modality, and can be used as an element of a more general tomography reconstruction algorithm.

22.  In fluorescence images using Wiener filter in wavelet domain

M. Hejazi
Proceeding
11th International congress of the IUPESM, Medical Physics and Biomedical Engineering , Munich, 2009, Germany

23.  Development of an algorithm for reducing scatter distribution in fluorescence images using Wiener filter in wavelet domain

E.B.Najafzadeh, M.Hejazi, H.Mohammadreza, M.Rudin, F.Stuker, A.Shirkavand. O. D?ssel and W.C. Schlegel
Journal Paper
(Eds.): WC IFMBE Proceedings 25/IV, p. 1869–1872, 2009

24.  Experimental and numerical study on simultaneous effects of scattering and absorption on fluorescence spectroscopy of a breast phantom

M A.Ansari, R Massudi, M.Hejazi
Journal Paper
Optics and laser Technology,2009 Volume 41, Issue 6, September 2009, Pages 746-750

Abstract:

Detection of dysplastic lesions can decrease morbidity and mortality caused by cancer. The fluorescence spectroscopy is a noninvasive method of detecting dysplasia in several organs. During dysplastic progression, fluorescence intensity of spectrum is changed due to variation in absorption and scattering coefficients of tissue. In this work we have experimentally verified simultaneous effects of scattering and absorption coefficients on fluorescence intensity of different tissue like phantoms with the same optical properties as the human breast ductal carcinoma. The results are compared with those obtained by Monte Carlo simulation and good agreement between them is observed. This provides an important detecting method to discriminate dysplastic tissue from normal tissue.
Keywords: Turbid media; Light propagation; Fluorescence

25.  Improvement of depth reconstruction in optical imaging using diffusion equation for spherical sources

Journal Paper
15th congress of Iranian optics and photonics, Isfahan 2009, Iran

26.  Evaluation of reflection optical imaging characteristic using fluorescence with near infrared wavelength at different depths of tissue equivalent phantom

Hamed Shoghi, Marjaneh Hejazi, MohammadAli Oghabian, Reza Massoudi, Hanieh Mohammadreza, Afshan Shirkavand
Journal Paper
Lasers in medicine Journal, Vol.5, No.3&4,p.29,2008

27.  Increase depth reconstruction accuracy of fluorescence reflectance imaging using improved depth dependent point spread function

Journal Paper
World Molecular Imaging congress,France 2008

28.  Measurment of choroidal neovascular area in Age-related macular degeneration using modified Otsu's thresholding method

Hanieh Mohammadreza, M. Hejazi, MohammadAli Oghabian, Alireza Ahmadian, Masoud Naseripour, Mohammadreza Zarin, Khalil Ghasemi, Hosein Nazari
Journal Paper
Iranian Journal of Medical Physics, Vol.5, No.2, p.77-84, 2008

29.  A new Monte Carlo code used for absorption simulation of skin-tissue interaction

A.Shirkavand,.S.Sarkar, M.Hejazi, Ataie-Fashtami, Alinaghizadeh
Journal Paper
Chinenese Optics Letter.2007 5, 238-240

30.  Characterizing point spread functions of wide field epi-illumination microscopy using quantum dot in turbid medium

M.Hejazi, Alois Renn, M. An Oghabian, R Massudi
Journal Paper
Iranian Laser in medicine. 5(1) 1387,25-31.2007

31.  Evaluation of LITCIT software for thermal simulation of superficial lasers like hair removal lasers

A. shirkavand, S.Sarkar, M.Hejazi, L.Ataei, M.R.Alinaghizadeh
Journal Paper
Indian Journal of Dermatology;2007 52(3), 145-149

32.  Evaluation of LITCIT software for thermal simulation of superficial lasers like hair removal lasers skin tissue

A.Shirkavand,.S.Sarkar, M.Hejazi, L.Ataie-Fashtami, Alinaghizadeh
Journal Paper
125(1) 1387,7-11.2007

33.  Introduction and Evaluation of litcit software for thermal simulation of hair removal lasers

A Shirkavand, S Sarkar, M Hejazi, L Ataie-Fashtami, MR Alinaghizadeh
Proceeding
European Dermatology and Venereology, Vienna.2007

34.  Comparison of Laser-Ultrasound Detection Systems Sensitivity with a Broadband Ultrasonic Source for Biomedical Applications

M.Hejazi, M.D Abolhassani, A. Ahmadian
Journal Paper
Archives of Medical Research. 2006; 37:322-327

Abstract:

BACKGROUND:Laser ultrasound detection systems are used for noninvasive imaging of internal structures and function of soft tissues. The detection systems with a high sensitivity can be used for detecting small tumors located deeply in human tissues, such as the breast. In this study, the sensitivity of existing ultrasonic detection systems has been compared experimentally by using thermoelastic waves as a broadband ultrasonic source.
METHODS:For the comparison, an optical stress transducer, a polyvinylidene difluoride (PVDF) sheet and a calibrated PVDF needle hydrophone were used. To ensure that all detection systems were interrogated by the same ultrasonic field, a small optical instrument was constructed to fix the generating laser head. The sensitivity was evaluated by measuring signal-to-noise ratios (SNRs) and noise equivalent pressures (NEPs).
RESULTS:The PVDF system, with a 4 kPa NEP, has a 22-dB better performance than the optical stress transducer. The optical stress transducer showed nearly the same sensitivity as the hydrophone for detecting ultrasound waves at a 1-cm distance.
CONCLUSIONS:PVDF detection system provides a useful tool for imaging of soft tissues because of its high sensitivity and broadband detection range.

35.  Design of a confocal microscope for investigating absorption coefficient

Journal Paper
13th Conference on optics and Photons of Iran , Rafsanjan, 2006

36.  Photoacoustic tomography of a tissue phantom using a two-dimensional optical stress transducer

Journal Paper
World Congress on Medical Physics and Biomedical Engineering, 2006, South Korea

37.  A comparison study of an optical detection system sensitivity with those of PVDF detection system and PVDF needle hydrophone in a same acoustic field for optoacoustic tomography

M. D Abolhassani, M.Hejazi, A. Ahmadian
Journal Paper
Chinese Optics Letters.11(3). 2005

38.  Diffraction-free acoustic detection for optoacoustic depth profiling of tissue using an optically transparent polyvinylidene fluoride pressure transducer operated in backward and forward mode

M. Jaeger, J.J Niederhauser, M.Hejazi, M Frenz
Journal Paper
Journal of Biomedical Optic.2005 .10(02), p. 1-7

Abstract:

An optoacoustic detection method suitable for depth profiling of optical absorption of layered or continuously varying tissue structures is presented. Detection of thermoelastically induced pressure transients allows reconstruction of optical properties of the sample to a depth of several millimeters with a spatial resolution of 24 mum. Acoustic detection is performed using a specially designed piezoelectric transducer, which is transparent for optical radiation. Thus, ultrasonic signals can be recorded at the same position the tissue is illuminated. Because the optoacoustical sound source is placed in the pulsed-acoustic near field of the pressure sensor, signal distortions commonly associated with acoustical diffraction are eliminated. Therefore, the acoustic signals mimic exactly the depth profile of the absorbed energy. This is illustrated by imaging the absorption profile of a two-layered sample with different absorption coefficients, and of a dye distribution while diffusing into a gelatin phantom.

39.  Optical Stress transducer with high sensitivity and high bandwidth for medical applications

M. Hejazi
Journal Paper
Iranian Medical Physics Journal.5 (2).2005

40.  Transparent ITO coated PVDF transducer for optoacoustic depth profiling

Niederhauser, M. Jaeger, M. Hejazi, H. Keppner b, M. Frenz
Journal Paper
Transparent ITO coated PVDF transducer for optoacoustic depth profiling” Optics Communication, 2005; 401-406

Abstract

In optoacoustic depth profiling, illumination of absorbing biological tissue with short laser pulses generates pressure transients that are recorded with an acoustic transducer. The time profile of these pressure transients mirrors the depth resolved light absorption in the tissue, a relevant parameter, for example for transcutaneous medication penetration or in diagnosis of portwine stain. We propose a novel piezoelectric polyvinylidene fluoride transducer with transparent indium tin oxide (ITO) electrodes. The possibility of laser illumination through the transducer allows backward mode optoacoustic detection, a prerequisite to all parts of the human body not accessible from two sides. The sensitivity of the ITO transducer is comparable to classical metal coated transducers. Its transparency allows direct placement on the skin and combined with homogeneous large area illumination a one-dimensional acoustic propagation model becomes valid. This eliminates the need for computational compensation of diffraction effects. The influence of illumination area was illustrated in a comparison of the two transducers with an absorbing methylene blue sample in forward and backward mode.
Keywords: Optoacoustic imaging; Pressure transducer; Laser-induced ultrasound; Backward mode; Stress analysis; Acoustic diffraction