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.

BACKGROUND/AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSION: This study clearly indicates that by changing SSD and lighting color, manual and automatic detection of BCC lesions borders can be enhanced.

Radiolabeled nanoceria probes may reduce oxidative damages and risk of cancer: a hypothesis for radioisotope-based imaging procedures.

Low-dose ionizing radiations are commonly utilized in medical centers for diagnostic imaging procedures. Unfortunately, the absorption of ionizing radiation generates reactive chemical species that could damage cells. In diagnostic radioisotope-based imaging procedures, the radiological exposures by gamma emitter imaging probes such as radioactive technetium ((99m)Tc) could express low risk of cancer. Recently, many studies have documented cell protective, neuro-protective, anti-inflammatory and cardio-protective properties of cerium oxide nanoparticles (nanoceria) as a result of their antioxidant and free radical scavenger properties. Since there is no safe level of ionizing radiations, then we hypothesize that radiolabeled nanoceria might be an interesting probe to reduce cancer risk and other related oxidative stresses. We also provide a synthetic scheme of nanoceria functionalization with fluorine radiolabeled ligands as an exemplary approach. In conclusion, using nanoceria to combine radioisotope-based imaging probes with antioxidant activity might open new way to protect patient against radioactive emission of radioisotopes and ionizing radiations in several radioisotope-based imaging applications, in particular for patients who need frequent imaging procedures and children who are more susceptible to radiation.

Monte Carlo simulations and radiation dosimetry measurements of 142Pr capillary tube-based radioactive implant (CTRI): a new structure for brachytherapy sources.

OBJECTIVE: Previously, a promising ß(-)-emitting praseodymium-142 glass seed was proposed for brachytherapy of prostate cancer. In accordance with the previous study, a (142)Pr capillary tube-based radioactive implant (CTRI) was suggested as a source with a new structure to enhance application of ß(-)-emitting radioisotopes such as (142)Pr in brachytherapy. METHODS: Praseodymium oxide powder was encapsulated in a glass capillary tube. Then, a thin and flexible fluorinated ethylene propylene Teflon(®) layer sealed the capillary tube. The source was activated in the Tehran Research Reactor by the (141)Pr(n,γ) (142)Pr reaction. Measurements of the dosimetric parameters were performed using GafChromic(®) radiochromic film. In addition, the dose rate distribution of (142)Pr CTRI was calculated by modeling (142)Pr source in a water phantom using Monte Carlo N-Particle Transport (MCNP5) Code. RESULTS: The active source was unreactive and did not leak in water. In comparison with the earlier proposed (142)Pr seed, the suggested source showed similar desirable dosimetric characteristics. Moreover, the (142)Pr CTRI production procedure may be technically and economically more feasible. The mass of praseodymium in CTRI structure could be greater than that of the (142)Pr glass seed; therefore, the required irradiation time and the neutron flux could be reduced. CONCLUSION: A (142)Pr CTRI was proposed for brachytherapy of prostate cancer. The dosimetric calculations by the experimental measurements and Monte Carlo simulation were performed to fulfill the requirements according to the American Association of Physicists in Medicine recommendations before the clinical use of new brachytherapy sources. The characteristics of the suggested source were compared with those of the previously proposed (142)Pr glass seed.

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

OBJECTIVE: Many studies have attempted to assess the significance of the use of the ß(-)particle emitter praseodymium-142 ((142)Pr) in cancer treatment. As praseodymium oxide (Pr(2)O(3)) 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 (Nd(2)O(3)) induced massive vacuolization and cell death in non-small-cell lung cancer. In this work, the production of (142)Pr was studied and water-dispersible nanosized Pr(2)O(3) was proposed to improve the application of (142)Pr in nuclear medicine. MATERIALS AND METHODS: Data from different databases pertaining to the production of (142)Pr were compared to evaluate the accuracy of the theoretical calculations. Water-dispersible nanosized Pr(2)O(3) was prepared using a poly(ethylene glycol) (PEG) coating or PEGylation method as a successful mode of drug delivery. Radioactive (142)Pr(2)O(3) was produced via a (142)Pr(n,γ)(142)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-Pr(2)O(3) particles remained in suspension and most of them settled out of the water. Interestingly, the PEGylated Pr(2)O(3) nanoparticles were water dispersible. After neutron bombardment of the sample, a stable colloidal (142)Pr(2)O(3) was formed. CONCLUSION: The radioactive (142)Pr(2)O(3) decays to the stable (142)Nd(2)O(3). The suggested colloidal (142)Pr(2)O(3) as a multifunctional therapeutic agent could have dual roles in cancer treatment as a radiotherapeutic agent using nanosized (142)Pr(2)O(3) and as an autophagy-inducing agent using nanosized (142)Nd(2)O(3).

Scope of nanotechnology-based radiation therapy and thermotherapy methods in cancer treatment.

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.

Bremsstrahlung parameters of praseodymium-142 in different human tissues: a dosimetric perspective for (142)Pr radionuclide therapy.

OBJECTIVE: Praseodymium-142 [T 1/2 = 19.12 h, [Formula: see text] = 2.162 MeV (96.3%), Eγ = 1575 keV (3.7%)] is one of the (141)Pr radioisotopes. Many studies have been attempted to assess the significance of usage (142)Pr in radionuclide therapy. In many studies, the dosimetric parameters of (142)Pr sources were calculated by modeling (142)Pr 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 (142)Pr Bremsstrahlung parameters. METHODS: The Bremsstrahlung parameters of (142)Pr 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 (142)Pr 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-cm(2)/MBq-h) compared to the other tissues and highest for cortical bone (2.4764 × 10(-3) C/kg-cm(2)/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-cm(2)/MBq-h which was greater than sacrum and spongiosa bones. Moreover, according to (A release)Br of (142)Pr, the patients receiving (142)Pr do not have to be hospitalized for radiation precautions and the Bremsstrahlung production does not prevent the therapy for outpatients. CONCLUSION: However, modeling (142)Pr source in water phantom for simulation of (142)Pr 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 (142)Pr is involved in radionuclide therapy.

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

Radionuclides of rare earth elements are gaining importance as emerging therapeutic agents in nuclear medicine. ß(-)-particle emitter 142Pr [T (1/2) = 19.12 h, E(-)ß = 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 ß(-)-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.