Martin Bakht - Academia.edu (original) (raw)

Papers by Martin Bakht

Impact of various color LED flashlights and different lighting source to skin distances on the manual and the computer-aided detection of basal cell carcinoma borders

Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI), 2013

Background/aimsQuantitative analysis based on digital skin image has been proven to be helpful in... more Background/aimsQuantitative analysis based on digital skin image has been proven to be helpful in dermatology. Moreover, the borders of the basal cell carcinoma (BCC) lesions have been challenging borders for the automatic detection methods. In this work, a computer-aided dermatoscopy system was proposed to enhance the clinical detection of BCC lesion borders.Quantitative analysis based on digital skin image has been proven to be helpful in dermatology. Moreover, the borders of the basal cell carcinoma (BCC) lesions have been challenging borders for the automatic detection methods. In this work, a computer-aided dermatoscopy system was proposed to enhance the clinical detection of BCC lesion borders.MethodsFifty cases of BCC were selected and 2000 pictures were taken. The lesion images data were obtained with eight colors of flashlights and in five different lighting source to skin distances (SSDs). Then, the image-processing techniques were used for automatic detection of lesion borders. Further, the dermatologists marked the lesions on the obtained photos.Fifty cases of BCC were selected and 2000 pictures were taken. The lesion images data were obtained with eight colors of flashlights and in five different lighting source to skin distances (SSDs). Then, the image-processing techniques were used for automatic detection of lesion borders. Further, the dermatologists marked the lesions on the obtained photos.ResultsConsiderable differences between the obtained values referring to the photographs that were taken at super blue and aqua green color lighting were observed for most of the BCC borders. It was observed that by changing the SSD, an optimum distance could be found where that the accuracy of the detection reaches to a maximum value.Considerable differences between the obtained values referring to the photographs that were taken at super blue and aqua green color lighting were observed for most of the BCC borders. It was observed that by changing the SSD, an optimum distance could be found where that the accuracy of the detection reaches to a maximum value.ConclusionThis study clearly indicates that by changing SSD and lighting color, manual and automatic detection of BCC lesions borders can be enhanced.This study clearly indicates that by changing SSD and lighting color, manual and automatic detection of BCC lesions borders can be enhanced.

Berechnung der Exposition von Gewebe, DNA und RNA durch Betainduzierte Bremsstrahlung von 198Au als therapeutisches Radionuklid

Published Ahead-of-Print-Last Updated: October 25, 2012

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Annals of nuclear …, 2013

Conformal dose coverage for accelerated partial breast irradiation or radiotherapy boost can be o... more Conformal dose coverage for accelerated partial breast irradiation or radiotherapy boost can be obtained with AccuBoost® D-shaped brachytherapy applicators using a flattened surface positioned near the patient. Three D-shaped applicators ͑D45/D53/D60͒ were dosimetrically characterized using Monte Carlo methods ͑MCNP5͒, air ionization chambers ͑Farmer and Markus͒, and radiochromic film ͑GafChromic EBT͒ in polystyrene and ICRU 44 breast tissue. HDR 192 Ir source dwell times were either constant or optimized to improve skin dose uniformity. Scatter dose decreased as depth decreased. 10 mm beyond the applicator aperture, dose reductions of 90% and 51% were observed at depths of 0 and 30 mm, respectively. Similarly, planar dose uniformity improved as depth decreased and was also due to scatter and applicator geometry. Dose uniformity inside the applicator aperture was approximately 11% and 15% for all three applicators at the skin and 30 mm deep, respectively. Depth dose measurements in polystyrene using ion chamber and radiochromic film agreed with Monte Carlo results within 2%. Discrepancies between film and Monte Carlo dose profiles at 30 mm depth were within 1%.

Preparation of radioactive praseodymium oxide as a multifunctional agent in nuclear medicine: expanding the horizons of cancer therapy using nanosized neodymium oxide

Nuclear medicine communications, Jan 1, 2012

OBJECTIVE: Many studies have attempted to assess the significance of the use of the β-particle em... more OBJECTIVE: Many studies have attempted to assess the significance of the use of the β-particle emitter praseodymium-142 (Pr) in cancer treatment. As praseodymium oxide (Pr2O3) powder is not water soluble, it was dissolved in HCl solution and the resultant solution had to be pH adjusted to be in an injectable radiopharmaceutical form. Moreover, it was shown that the nanosized neodymium oxide (Nd2O3) induced massive vacuolization and cell death in non-small-cell lung cancer. In this work, the production of Pr was studied and water-dispersible nanosized Pr2O3 was proposed to improve the application of Pr in nuclear medicine. MATERIALS AND METHODS: Data from different databases pertaining to the production of Pr were compared to evaluate the accuracy of the theoretical calculations. Water-dispersible nanosized Pr2O3 was prepared using a poly(ethylene glycol) (PEG) coating or PEGylation method as a successful mode of drug delivery. Radioactive Pr2O3 was produced via a Pr(n,γ)Pr reaction by thermal neutron bombardment of the prepared sample. RESULTS: There was good agreement between the reported experimental data and the data based on nuclear model calculations. In addition, a small part of nano-Pr2O3 particles remained in suspension and most of them settled out of the water. Interestingly, the PEGylated Pr2O3 nanoparticles were water dispersible. After neutron bombardment of the sample, a stable colloidal Pr2O3 was formed. CONCLUSION: The radioactive Pr2O3 decays to the stable Nd2O3. The suggested colloidal Pr2O3 as a multifunctional therapeutic agent could have dual roles in cancer treatment as a radiotherapeutic agent using nanosized Pr2O3 and as an autophagy-inducing agent using nanosized Nd2O3.

Current cancer drug …, Jan 1, 2012

The main aim of nanomedicine is to revolutionize the health care system and find effective approa... more The main aim of nanomedicine is to revolutionize the health care system and find effective approaches to fighting fatal diseases. Therapeutic beams, which are employed in radiation therapy, do not discriminate between normal and cancerous cells and must rely on targeting the radiation beams to specific cells. Interestingly, the application of nanoscale particles in radiation therapy has aimed to improve outcomes in radiation therapy by Increasing toxicity in tumors and reducing it in normal tissues. This review focuses on approaches to nanotechnology-based cancer radiation therapy methods such as radionuclide therapy, photodynamic therapy, and neutron capture therapy. Moreover, we have investigated nanotechnology-based thermotherapy methods, including hyperthermia and thermoablation, as non-ionizing modalities of treatment using thermal radiation. The results strongly demonstrate that nanotechnology-based cancer radiation therapy and thermotherapy methods hold substantial potential to improve the efficacy of anticancer radiation and thermotherapy modalities.

Annals of nuclear …, Jan 1, 2012

Objective Praseodymium-142 [T 1/2 = 19.12 h, Eb-E− = 2.162 MeV (96.3%), Eγ = 1575 keV (3.7%)] is... more Objective
Praseodymium-142 [T 1/2 = 19.12 h, Eb-E− = 2.162 MeV (96.3%), Eγ = 1575 keV (3.7%)] is one of the 141Pr radioisotopes. Many studies have been attempted to assess the significance of usage 142Pr in radionuclide therapy. In many studies, the dosimetric parameters of 142Pr sources were calculated by modeling 142Pr sources in the water phantom and scoring the energy deposited around it. However, the medical dosimetry calculations in water phantom consider Bremsstrahlung production, raising the question: “How important is to simulate human tissues instead of using water phantom?” This study answers these questions by estimation of 142Pr Bremsstrahlung parameters.
Methods
The Bremsstrahlung parameters of 142Pr as therapeutic beta nuclides in different human tissues (adipose, blood, brain, breast, cell nucleus, eye lens, gastrointestinal tract, heart, kidney, liver, lung deflated, lymph, muscle, ovary, pancreas, cartilage, red marrow, spongiosa, yellow marrow, skin, spleen, testis, thyroid and different skeleton bones) were calculated by extending the national council for radiation protection model. The specific Bremsstrahlung constant (Γ Br), probability of energy loss by beta during Bremsstrahlung emission (P Br) and Bremsstrahlung activity (A release)Br were estimated. It should be mentioned that Monte Carlo simulation was used for estimation of 142Pr Bremsstrahlung activity based on the element compositions of different human tissues and the calculated exposures from the anthropomorphic phantoms.
Results
Γ Br for yellow marrow was smallest amount (1.1962 × 10−3 C/kg-cm2/MBq-h) compared to the other tissues and highest for cortical bone (2.4764 × 10−3 C/kg-cm2/MBq-h), and, overall, Γ Br for skeletal tissues were greater than other tissues. In addition, Γ Br breast was 1.8261 × 10−3 C/kg-cm2/MBq-h which was greater than sacrum and spongiosa bones. Moreover, according to (A release)Br of 142Pr, the patients receiving 142Pr do not have to be hospitalized for radiation precautions and the Bremsstrahlung production does not prevent the therapy for outpatients.
Conclusion
However, modeling 142Pr source in water phantom for simulation of 142Pr source in soft tissues could be acceptable due to similarity of Γ Br in water and soft tissues; this approximation is a gross computation in the mediums encompassing high atomic numbers. These data may be practical in the investigation of Bremsstrahlung absorbed dose where 142Pr is involved in radionuclide therapy.

Journal of …, Jan 1, 2012

198 Au (b max = 0.96 MeV (98.6 %), c max = 0.412 MeV (95.5 %) and T 1/2 = 2.7 days) is a radionuc... more 198 Au (b max = 0.96 MeV (98.6 %), c max = 0.412 MeV (95.5 %) and T 1/2 = 2.7 days) is a radionuclide with very appealing characteristics. 198 Au has been widely used to treat the uterus, bladder, cervix, prostate, melanoma, breast, skin and other cancers. In the present study, cationic 198 Au ?3 and nonionic 198 Au 0 are prepared following thermal neutron irradiation of commercially available natural gold compounds in Tehran Research Reactor via the nat Au(n,c) 198 Au reaction. The prospects in the production of pure 198 Au 0 and 198 Au ?3 for radionuclide therapy are discussed and effect of reduction on the activity of radioactive gold is evaluated. Au 0 particles were synthesized via NaBH 4 reduction of aqueous solutions of hydrogen tetrachloroaurate trihydrate. Then two quartz tubes were charged with cationic 198 Au 3? and nonionic 198 Au 0 . After irradiation by thermal neutrons, the samples were analyzed for a period of 1 month by liquid scintillation counter and high purity germanium detector. As a result, nat Au 3? reduction process had no significant effect on the activity of the 198 Au sample. In conclusions, natural gold thermal neutron activation cross section is reasonably high for medical application.

Overview of mercury radionuclides and nuclear model calculations of 195Hgm,g and 197Hgm,g to evaluate experimental cross section data

Theoretical studies of isomers through nuclear reaction model calculations significantly assist t... more Theoretical studies of isomers through nuclear reaction model calculations significantly assist the estimation of the different experimental data reported from different databases. In this paper, the production methods and the applications of mercury radionuclides are reviewed with special attention to the feasibility of the cyclotron production of mercury radionuclides, including 195Hgm,g and 197Hgm,g. First, talys and empire codes were employed to illustrate the formation of both the isomeric and the ground states of the mercury radionuclides. Then the excitation function was calculated via a variety of nuclear processes using the codes and the data taken from the TENDL database. Then we compared the data with the reported experimental measurement. The mercury radionuclide production yield was evaluated with concentration on the excitation function calculations and the stopping powers of the projectiles in the targets. Last, the 197Au(d,2n) and 197Au(p,3n) reactions were selected as the best reactions to produce 197Hgm,g and 195Hgm,g, respectively.

A novel technique for simultaneous diagnosis and radioprotection by radioactive cerium oxide nanoparticles: study of cyclotron production of 137mCe

Application of nanoparticles in nuclear medicine has aimed to develop diagnosis and therapeutic t... more Application of nanoparticles in nuclear medicine has aimed to develop diagnosis and therapeutic techniques. Cerium oxide nanoparticles (CNPs) are expected to be useful for protection of healthy tissue from radiation-induced harm and could serve therapeutic function. Among a variety of cerium radioisotopes, 137mCe (T 1/2 = 34.4 h, IT (99.22%), β+ (0.779%)) could be a novel candidate radionuclide in the field of diagnosis owing to its appropriate half-life, 99.91% natural abundance of target and its intense gamma line at 254.29 keV. In this study, 137mCe excitation function via the natLa(p,3n) reaction was calculated by TALYS-1.2 and EMPIRE-3 codes. The excitation function calculations demonstrated that the natLa(p,3n)137mCe reaction leads to the formation of the 136/138Ce isotopic contamination in the 22–35 MeV energy range. Interestingly, the isotopic impurities of 137mCe could serve radio protector function. Overall results indicate that the cyclotron produced 137mCeO2 nanoparticles by irradiation of a target encompassing lanthanum oxide nanoparticles could be a potent alternative for conventional diagnostic radionuclides with simultaneous radioprotection capacity.

Internal radiotherapy techniques using radiolanthanide praseodymium-142: a review of production routes, brachytherapy, unsealed source therapy

Annals of Nuclear Medicine

Radionuclides of rare earth elements are gaining importance as emerging therapeutic agents in nuc... more Radionuclides of rare earth elements are gaining importance as emerging therapeutic agents in nuclear medicine. β(-)-particle emitter 142Pr [T (1/2) = 19.12 h, E(-)β = 2.162 MeV (96.3%), Eγ = 1575 keV (3.7%)] is one of the praseodymium-141 (100% abundant) radioisotopes. Production routes and therapy aspects of 142Pr will be reviewed in this paper. However, 142Pr produces via 141Pr(n, γ) 142Pr reaction by irradiation in a low-fluence reactor; 142Pr cyclotron produced, could be achievable. 142Pr due to its high β(-)-emission and low specific gamma γ-emission could not only be a therapeutic radionuclide, but also a suitable radionuclide in order for biodistribution studies. Internal radiotherapy using 142Pr can be classified into two sub-categories: (1) unsealed source therapy (UST), (2) brachytherapy. UST via 142Pr-HA and 142Pr-DTPA in order for radiosynovectomy have been proposed. In addition, 142Pr Glass seeds and 142Pr microspheres have been utilized for interstitial brachytherapy of prostate cancer and intraarterial brachytherapy of arteriovenous malformation, respectively.

Practicality of the cyclotron production of radiolanthanide 142 Pr: a potential for therapeutic applications and biodistribution studies

Journal of Radioanalytical and …, Jan 1, 2011

Abstract Radiolanthanide praseodymium-142 (T 1/2= 19.12 h, E β−= 2.162 MeV (96.3%), Eγ= 1575 keV ... more Abstract Radiolanthanide praseodymium-142 (T 1/2= 19.12 h, E β−= 2.162 MeV (96.3%), Eγ= 1575 keV (3.7%)) due to its high β-emission and low specific γ-emission could not only be a therapeutic radionuclide, but also a suitable radionuclide in order for biodistribution studies. Conventionally, 142 Pr produces via 141 Pr (n, γ) 142 Pr reaction by irradiation in a low-fluence reactor and this study evaluates cyclotron reaction production of it. 142 Pr excitation function via nat La (α, n) 142 Pr, 142 Ce (p, n) 142 Pr, and nat Pr (d, p) 142 Pr ...