The thermoluminescence response of doped SiO2 optical fibres subjected to photon and electron irradiations

Modern linear accelerators, the predominant teletherapy machine in major radiotherapy centres worldwide, provide multiple electron and photon beam energies. To obtain reasonable treatment times, intense electron beam currents are achievable. In association with this capability, there is considerable demand to validate patient dose using systems of dosimetry offering characteristics that include good spatial resolution, high precision and accuracy. Present interest is in the thermoluminescence response and dosimetric utility of commercially available doped optical fibres. The important parameter for obtaining the highest TL yield during this study is to know the dopant concentration of the SiO₂ fibre because during the production of the optical fibres, the dopants tend to diffuse. To achieve this aim, proton-induced X-ray emission (PIXE), which has no depth resolution but can unambiguously identify elements and analyse for trace elements with detection limits approaching μg/g, was used. For Al-doped fibres, the dopant concentration in the range 0.98–2.93 mol% have been estimated, with equivalent range for Ge-doped fibres being 0.53–0.71 mol%. In making central-axis irradiation measurements a solid water™ phantom was used. For 6-MV photons and electron energies in the range 6, 9 and 12 MeV, a source to surface distance of 100 cm was used, with a dose rate of 400 cGy/min for photons and electrons. The TL measurements show a linear dose–response over the delivered range of absorbed dose from 1 to 4 Gy. Fading was found to be minimal, less than 10% over five days subsequent to irradiation. The minimum detectable dose for 6-MV photons was found to be 4, 30 and 900 μGy for TLD-100 chips, Ge- and Al-doped fibres, respectively. For 6-, 9- and 12-MeV electron energies, the minimum detectable dose were in the range 3–5, 30–50 and 800–1400 μGy for TLD-100 chip, Ge-doped and Al-doped fibres, respectively.     

Synthesis and characterization of gold nanostructured Chorin e6 for Photodynamic Therapy

Photodynamic therapy is an alternative treatment for cancer based on cellular uptake of a photosensitizer, illuminated with an appropriate wavelength in the presence of oxygen. A cascade of reactions generates reactive oxygen species leading to cell death. Using carbodiimide chemistry, chlorin e6 (Ce6) was covalently bonded to thiourea, and (via the sulphur end group) to gold nanoparticles (AuNPs), forming the Ce6-AuNP complex. Ce6 absorbs in the range 650–680 nm, where the coefficient of biological tissue absorption is low (part of the therapeutic window), which is ideal for biological application. Transmission Electron Microscopy, UV–vis spectroscopy, Fourier transform Infrared Spectroscopy and Zeta potential measurements were completed to characterize the Ce6-AuNP complex. The bare AuNPs have an average diameter of 18 ± 4 nm. A line of human breast carcinoma cells (MDA-MB-468) was used to determine whether Ce6 functionalization to AuNPs potentiate its activity. Trypan blue assays were used to assess cell viability. In the absence of light, Ce6 either alone or bounded to AuNPs was not cytotoxic. When irradiated at 660 nm, the cytotoxicity of Ce6-AuNP was higher than Ce6 alone for MDA-MB-468 cells using 4 h incubation. AuNPs without Ce6 showed no cytotoxic.     

Fluorescence spectroscopy in the visible range for the assessment of UVB radiation effects in hairless mice skin

Ultraviolet (UV) radiation may induce skin alterations as observed in photoaging. Some recognized modifications are epidermal hyperplasia, amorphous deposition of degraded elastic fibers and reduction in the number of collagen fibers. They alter the tissue biochemical properties that can be interrogated by steady state fluorescence spectroscopy (SSFS). In this study, we monitored the changes in endogenous fluorescence emission from hairless mice skin during a protocol of photoaging using UVB irradiation. To perform the fluorescence spectroscopy, it was used a violet laser (408 nm) to induce the native fluorescence that is emitted in the visible range. Under 408 nm excitation, the emission spectrum showed bands with peaks centered around 510, 633 and 668 nm for irradiated and control groups. A relative increase of the fluorescence at 633 nm emission on the flank was observed with time when compared to the ventral skin at the same animal and the non-irradiated control group. We correlated the emission at 633 nm with protoporphyrin IX (PpIX), and our hypothesis is that the PpIX metabolism in the photoaged and aged skin are different. PpIX fluorescence intensity in the photoaged skin is higher and more heterogeneous than in the aged skin. Notwithstanding, more spectroscopic and biochemistry studies investigating the 510 and 633 nm emission are needed to confirm this hypothesis.     

High-power electron beam tests of a liquid-lithium target and characterization study of 7Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy

A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the ⁷Li(p,n)⁷Be reaction and it will overcome the major problem of removing the thermal power >5 kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux.In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4 kW/cm² and volumetric power density around 2 MW/cm³ at a lithium flow of ~4 m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (σ=~2 mm) 1.91 MeV, 3 mA proton beam. A high-intensity proton beam irradiation (1.91–2.5 MeV, 2 mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator.In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91 MeV) ⁷Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors.     

Synthesis and characterization of coordination polymer nanoparticles as radioisotope tracers

Coordination polymer nanoparticles (NPs) with gamma-emitting nuclide (Au-198), 411 keV, 675 keV, 822 keV and 1087 keV were prepared by coordination polymerization of the radioisotope Au³⁺ ions and 1,4-bis(imidazole-1-ylmethyl)benzene in an aqueous solution at room temperature for 3 h. Here, the radioisotope Au³⁺ ions were prepared by dissolution of Au-198 foil, which was prepared by neutron irradiation from the HANARO reactor, in KCN aqueous solution. The successful synthesis of the radioisotope coordination polymer NPs with 5±0.5 nm was confirmed via UV–vis spectroscopy, Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectrometry (EDXS), Thermogravimetric analysis (TGA), and Gamma spectroscopy analysis. The synthesized radioisotope coordination polymer NPs can be used as radiotracers in science, engineering, and industrial fields.     

Application of jade samples for high-dose dosimetry using the EPR technique

The dosimeter characteristics of jade samples were studied for application in high-dose dosimetry. Jade is the common denomination of two silicates: jadeite and actinolite. The EPR spectra of different jade samples were obtained after irradiation with absorbed doses of 100 Gy up to 20 kGy. The jade samples present signals that increase with the absorbed dose (g-factors around 2.00); they can be attributed to electron centers. The EPR spectra obtained for the USA jade samples and their main dosimetric properties as reproducibility, calibration curves and energy dependence were investigated.     

Photodynamic action of palmatine hydrochloride on colon adenocarcinoma HT-29 cells

Palmatine hydrochloride (PaH) is a natural active compound from a traditional Chinese medicine (TCM). The present study aims to evaluate the effect of PaH as a new photosensitizer on colon adenocarcinoma HT-29 cells upon light irradiation. Firstly, the absorption and fluorescence spectra of PaH were measured using a UV–vis spectrophotometer and RF-1500PC spectrophotometer, respectively. Singlet oxygen (¹O₂) production of PaH was determined using 1, 3-diphenylisobenzofuran (DPBF). Dark toxicity of PaH was estimated using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cellular uptake of PaH in HT-29 cells was detected at different time intervals. Subellular localization of PaH in HT-29 cells was observed using confocal laser fluorescence microscopy. For photodynamic treatment, HT-29 cells were incubated with PaH and then irradiated by visible light (470 nm) from a LED light source. Photocytotoxicity was investigated 24 h after photodynamic treatment using MTT assay. Cell apoptosis was observed 18 h after photodynamic treatment using a flow cytometry with Annexin V/PI staining. Results showed that PaH has an absorption peak in the visible region from 400 nm to 500 nm and a fluorescence emission peak at 406 nm with an excitation wavelength of 365 nm. PaH was activated by the 470 nm visible light from a LED light source to produce ¹O₂. Dark toxicity showed that PaH alone treatment had no cytotoxicity to HT-29 cancer cells and NIH-3T3 normal cells after incubation for 24 h. After incubation for 40 min, the cellular uptake of PaH reached to the maximum and PaH was located in mitochondria. Photodynamic treatment of PaH demonstrated a significant photocytotoxicity on HT-29 cells. The rate of cell death increased significantly in a PaH concentration-dependent and light dose-dependent manner. Further evaluation revealed that the early and late apoptotic rate of HT-29 cells increased remarkably up to 21.54% and 5.39% after photodynamic treatment of PaH at the concentration of 5 μM and energy density of 10.8 J/cm². Our findings demonstrated that PaH as a naturally occurring photosensitizer has potential in photodynamic therapy on colon adenocarcinoma.     

Efficient fluorescence detection of protoporphyrin IX in metastatic lymph nodes of murine colorectal cancer stained with indigo carmine

Protoporphyrin IX (PpIX), a biochemical converted from 5-aminolevulinc acid (5-ALA) in living cells, is useful for intraoperative fluorescent detection of cancer metastasis in lymph nodes (LNs). However, unknown is whether the fluorescence of PpIX can be detected in the LNs when they coexist with indigo carmine, a blue dye commonly used for identification of sentinel LNs during surgery. To address this issue, we sought to evaluate the diagnostic usefulness of PpIX fluorescence in the presence of indigo carmine in a mouse LN metastasis model of rectal cancer after administration of 5-ALA. Spectral analysis of pure chemicals revealed that the absorption spectrum of indigo carmine widely overlapped with the fluorescence spectrum of PpIX specifically at the peak of 632 nm, a common emission wavelength for detecting PpIX, but not at the other peak of 700 nm. Due to such spectral overlap, the PpIX fluorescence intensity was significantly attenuated by mixture with indigo carmine at 632 nm, but not at 700 nm. Accordingly, fluorescent measurements of the mouse metastatic LN revealed more intense presentation of PpIX at 700 nm than at 632 nm, indicating that the diagnostic usefulness is greater at 700 nm than at 632 nm for the indigo carmine-dyed LNs after administration of 5-ALA. From these observations, we propose that the fluorescence measurement is more efficient at 700 nm than at 632 nm for detection of PpIX in metastatic LNs stained with indigo carmine.     

Photon irradiation response of photonic crystal fibres and flat fibres at radiation therapy doses

Radiation effects of photon irradiation in pure Photonic Crystal Fibres (PCF) and Flat fibres (FF) are still much less investigated in thermoluminescense dosimetry (TLD). We have reported the TL response of PCF and FF subjected to 6 MV photon irradiation. The proposed dosimeter shows good linearity at doses ranging from 1 to 4 Gy. The small size of these detectors points to its use as a dosimeter at megavoltage energies, where better tissue-equivalence and the Bragg–Gray cavity theory prevails.     

Synthesis,characterisation and in vitro investigation of photodynamic activity of 5-(4-octadecanamidophenyl)-10,15,20-tris(N-methylpyridinium-3-yl)porphyrin trichloride on HeLa cells using low light fluence rate

Photodynamic therapy (PDT) is a treatment that aims to kill cancer cells by reactive oxygen species, mainly singlet oxygen, produced through light activation of a photosensitiser (PS). Amongst photosensitisers that attracted the most attention in the last decade are cationic and amphiphilic molecules based on porphyrin, chlorin and phthalocyanine structures. Our aim was to join this search for more optimal balance of the lipophilic and hydrophilic moieties in a PS. A new amphiphilic porphyrin, 5-(4-octadecanamidophenyl)-10,15,20-tris(N-methylpyridinium-3-yl)porphyrin trichloride (5) was synthesised and characterised by ¹H NMR, UV–vis and fluorescence spectroscopy, and by MALDI-TOF/TOF spectrometry. In vitro photodynamic activity of 5 was evaluated on HeLa cell lines and compared to the activity of the hydrophilic 5-(4-acetamidophenyl)-10,15,20-tris(N-methylpyridinium-3-yl)porphyrin trichloride (7). Low fluence rate (2 mW cm⁻²) of red light (643 nm) was used for the activation, and both porphyrins showed a drug dose-response as well as a light dose-response relationship, but the amphiphilic porphyrin was presented with significantly lower IC₅₀ values. The obtained IC₅₀ values for 5 were 1.4 μM at 15 min irradiation time and 0.7 μM when the time of irradiation was 30 min, while for 7 these values were 37 and 6 times higher, respectively. These results confirm the importance of the lipophilic component in a PS and show a potential for 5 to be used as a PS in PDT applications.     

Photodynamic inactivation of Candida albicans biofilm: Influence of the radiant energy and photosensitizer charge

BackgroundThe aim of this study is to investigate the photoinactivation of C. albicans biofilm on acrylic resin discs (the standard material for dental prosthesis) using the photosensitizers Methylene Blue and a Protoporphyrin IX.MethodsEighteen thermally activated Methyl Methacrylate Polymers were used for the biofilm growth of Candida albicans ATCC 10231. Two photosensitizers were tested: methylene blue (50 μM) and protoporphyrin IX (10 μM). Two custom-made LEDs emitting at 660 nm and 630 nm with approximately 800 mW each were used for the irradiation, with duration ranging from 2 to 10 min.ResultsThis study demonstrates that MB decreased the aPDT CFUs by approximately two orders of magnitude, but the protoporphyrin was ineffective.ConclusionThe aPDT with MB significantly reduces (but does not sterilize) the amount of CFU after 10 min of irradiation, and it is not dose-dependent. The lack of effect of the protoporphyrin is likely because the negative charges of the proteoglycans present in the extracellular matrix repel the negative charges of the PS, thus preventing its diffusion in the cells.     

Characteristics of a new polymer gel for high-dose gradient dosimetry using a micro optical CT scanner

The properties of a new polymer gel with two sensitivities, made specifically for high-dose-gradient dosimetry, were investigated. The measurements were performed at NIST using a 1 cm×1 cm calibrated ⁶⁰Co field, and a 1 cm active diameter ⁹⁰Sr/⁹⁰Y beta particle source. A high-resolution laser CT scanner was used to quantify the response. The results show that the high-sensitivity gel responds linearly to the absorbed dose for doses from 0.5 up to 15 Gy, while the low-sensitivity one is linear up to 225 Gy. For both radiation types, the gel response remains stable in time up to a month after the irradiation. The response of the gel was found to have no dose rate dependence for dose rates ranging from 3.7 to 15 mGy/s. Within the measurement uncertainty, the gel response is more sensitive for beta particles than high energy photons.     

Methylene blue,curcumin and ion pairing nanoparticles effects on photodynamic therapy of MDA-MB-231 breast cancer cell

PurposeThe aim of current study was to use methylene blue-curcumin ion pair nanoparticles and single dyes as photosensitizer for comparison of photodynamic therapy (PDT) efficacy on MDA-MB-231 cancer cells, also various light sources effect on activation of photosensitizer (PS) was considered.MethodIon pair nanoparticles were synthesized using opposite charge ions precipitation and lyophilized. The PDT experiments were designed and the effect of PSs and light sources (Red LED (630 nm; power density: 30 mW cm⁻²) and blue LED (465 nm; power density: 34 mW cm⁻²)) on the human breast cancer cell line were examined. The effect of PS concentration (0–75 μg. mL⁻¹), incubation time, irradiation time and light sources, and priority in irradiation of blue or red lights were determined.ResultsThe results show that the ion pairing of methylene blue and curcumin enhance the photodynamic activity of both dyes and the cytotoxicity of ion pair nanoparticles on the MDA-231 breast cancer cell line. Blue and red LED light sources were used for photo activation of photosensitizers. The results demonstrated that both dyes can activate using red light LED better than blue light LED for singlet oxygen producing.ConclusionNano scale ion pair precipitating of methylene blue-curcumin enhanced the cell penetrating and subsequently cytotoxicity of both dyes together.     

Thermoluminescence characteristics of Nd-doped SiO2 optical fibers irradiated with the 60Co gamma rays

Thermoluminescence (TL) properties (radiation sensitivity, dose response, signal fading) of Nd-doped SiO₂ optical fibers irradiated with 1.25 MeV photons to 1–50 Gy were studied. The peak of the glow curve is around 190 °C regardless of the dose. The dose response is linear up to 50 Gy. The radiation sensitivity is 219 nC mg⁻¹ Gy⁻¹. The fiber can be a potential candidate for photon radiotherapy dosimetry due to its high radiation sensitivity, linear dose response in a wide range, slow fading, and high spatial resolution due to the small size of the fiber.     

Photodecomposition,photomutagenicity and photocytotoxicity of retinyl palmitate under He–Ne laser photoirradiation and its effects on photodynamic therapy of cancer cells in vitro

ObjectiveOur aim was to study photodecomposition, photomutagenicity and cytotoxicity of retinyl palmitate (RP), a principal storage form of vitamin A in humans and animals, under He–Ne laser photoirradiation. Moreover, the effect of different concentrations and timing protocol of antioxidants on photodynamic therapy (PDT) is contradictory, so the effect of RP (as antioxidant) on the PDT cytotoxicity was studied.MethodsPhotomutagenicity was tested by Ames test. Photodecomposition was studied by UV–vis spectroscopy. Cytotoxicity was measured with MTT-assay. Moreover, the effect of PDT, using hematoporphyrin derivatives (HpD) as photosensitizer under He–Ne laser irradiation (10 J/cm²), was studied on HeLa cells either with or without RP (1–100 μM) which incubated with the cells for short or long incubation period (1 h or 24 h) prior to PDT.ResultsNo photodecomposition of RP alone was obseved whereas there is a little photodecomposition of RP only in presence of HpD under irradiation with He–Ne laser. Moreover, no photomutagenicity was observed in Salmonella typhimurium strains under laser irradiation in presence or absence of HpD. RP alone (1–100 μM) significantly decrease the viability of HeLa cells. Laser irradiation of HeLa cells pre-incubated with RP alone for 24 h showed further significant decrease in viability of the cells. While RP incubations for 1 h before PDT had slight effect on the cells, 24 h incubation before PDT enhanced the cytotoxicity of PDT on HeLa cells.ConclusionsRP can be used 24 h before PDT to enhance its effects. RP is not mutagenic under irradiation with He–Ne laser.     

Dosimetry of 64Cu-DOTA-AE105, a PET tracer for uPAR imaging

⁶⁴Cu-DOTA-AE105 is a novel positron emission tomography (PET) tracer specific to the human urokinase-type plasminogen activator receptor (uPAR). In preparation of using this tracer in humans, as a new promising method to distinguish between indolent and aggressive cancers, we have performed PET studies in mice to evaluate the in vivo biodistribution and estimate human dosimetry of ⁶⁴Cu-DOTA-AE105.MethodsFive mice received iv tail injection of ⁶⁴Cu-DOTA-AE105 and were PET/CT scanned 1, 4.5 and 22 h post injection. Volume-of-interest (VOI) were manually drawn on the following organs: heart, lung, liver, kidney, spleen, intestine, muscle, bone and bladder. The activity concentrations in the mentioned organs [%ID/g] were used for the dosimetry calculation. The %ID/g of each organ at 1, 4.5 and 22 h was scaled to human value based on a difference between organ and body weights. The scaled values were then exported to OLINDA software for computation of the human absorbed doses. The residence times as well as effective dose equivalent for male and female could be obtained for each organ. To validate this approach, of human projection using mouse data, five mice received iv tail injection of another ⁶⁴Cu-DOTA peptide-based tracer, ⁶⁴Cu-DOTA-TATE, and underwent same procedure as just described. The human dosimetry estimates were then compared with observed human dosimetry estimate recently found in a first-in-man study using ⁶⁴Cu-DOTA-TATE.ResultsHuman estimates of ⁶⁴Cu-DOTA-AE105 revealed the heart wall to receive the highest dose (0.0918 mSv/MBq) followed by the liver (0.0815 mSv/MBq), All other organs/tissue were estimated to receive doses in the range of 0.02–0.04 mSv/MBq. The mean effective whole-body dose of ⁶⁴Cu-DOTA-AE105 was estimated to be 0.0317 mSv/MBq. Relatively good correlation between human predicted and observed dosimetry estimates for ⁶⁴Cu-DOTA-TATE was found. Importantly, the effective whole body dose was predicted with very high precision (predicted value: 0.0252 mSv/Mbq, Observed value: 0.0315 mSv/MBq) thus validating our approach for human dosimetry estimation.ConclusionFavorable dosimetry estimates together with previously reported uPAR PET data fully support human testing of ⁶⁴Cu-DOTA-AE105.     

EBT GAFCHROMICTM film dosimetry in compensator-based intensity modulated radiation therapy

The electron benefit transfer (EBT) GAFCHROMIC films possess a number of features making them appropriate for high-quality dosimetry in intensity-modulated radiation therapy (IMRT). Compensators to deliver IMRT are known to change the beam-energy spectrum as well as to produce scattered photons and to contaminate electrons; therefore, the accuracy and validity of EBT-film dosimetry in compensator-based IMRT should be investigated. Percentage-depth doses and lateral-beam profiles were measured using EBT films in perpendicular orientation with respect to 6 and 18 MV photon beam energies for: (1) different thicknesses of cerrobend slab (open, 1.0, 2.0, 4.0, and 6.0 cm), field sizes (5×5, 10×10, and 20×20 cm²), and measurement depths (D_max, 5.0 and 10.0 cm); and (2) step-wedged compensator in a solid phantom. To verify results, same measurements were implemented using a 0.125 cm³ ionization chamber in a water phantom and also in Monte Carlo simulations using the Monte Carlo N-particle radiation transport computer code. The mean energy of photons was increased due to beam hardening in comparison with open fields at both 6 and 18 MV energies. For a 20×20 cm² field size of a 6 MV photon beam and a 6.0 cm thick block, the surface dose decreased by about 12% and percentage-depth doses increased up to 3% at 30.0 cm depth, due to the beam-hardening effect induced by the block. In contrast, at 18 MV, the surface dose increased by about 8% and depth dose reduced by 3% at 30.0 cm depth. The penumbral widths (80% to 20%) increase with block thickness, field size, and beam energy. The EBT film results were in good agreement with the ionization chamber dose profiles and Monte Carlo N-particle radiation transport computer code simulation behind the step-wedged compensator. Also, there was a good agreement between the EBT-film and the treatment-planning results on the anthropomorphic phantom. The EBT films can be accurately used as a 2D dosimeter for dose verification and quality assurance of compensator-based C-IMRT.     

Endobronchial photodynamic therapy under fluorescence control: Photodynamic theranostics

BackgroundPhotodynamic therapy (PDT) has several advantages. However, one of the disadvantages is its inability to be individualized according to biological characteristics of malignant tumors. The objective of this study was to investigate a strategy for individualized endobronchial PDT in the treatment of centrally located non-small cell lung cancer.MethodsNew approach suggests taking fluorescence-based measurements of chlorine E6 photosensitizer (PS) accumulation in the malignant tumor tissue, and assess PS consumption rate during PDT. Two randomized groups of 45 patients took part in the comparative study of standard PDT procedure, 662 nm, pulse-periodic mode, therapeutic light (reference group – RG) versus the investigated individualized approach under fluorescence control after irradiation with violet light, 408 nm, diagnostic light (study group – SG). The PDT-treatment parameters and results of follow-up bronchoscopy were compared between the groups.Results43 (96%) of 45 patients in SG demonstrated intense fluorescence in the area of the tracheal/bronchial tumor stenosis. 4 (9%) of 45 patients (SG) demonstrated fluorescence of mucosa areas distant from the main tumor lesion after violet light irradiation. Mean fluence during the whole PDT procedure was 95 ± 20 J/cm² (range 60–130 J/cm²), which was significantly lower than in RG (p = 0.01). Total exposure time was significantly lower in SG (365 ± 65 s), compared with RG (690 ± 65 s), P = 0.001. According to the follow-up bronchoscopy the difference in the PDT-treatment results between the groups is statistically insignificant.ConclusionsThe investigated strategy suggests using fluorescence control of the efficacy of PDT-treatment (photodynamic theranostics) to optimize and individualize the PDT procedure.     

The new facility for neutron tomography of IPEN-CNEN/SP and its potential to investigate hydrogenous substances

A new facility for neutron tomography has been installed at the IEA-R1 nuclear research reactor of IPEN-CNEN/SP. A tomography can be obtained in 400 s and the spatial resolution in the image is 263 μm. The neutron dose per tomography, in the video camera used for image capture, is only 21 μSv, assures very few damages in its CCD sensor. Some selected objects were investigated and the obtained 3D images demonstrate the capability of the facility to investigate hydrogenous substances.