Irradiation Device Research Articles

Digital gamma activation autoradiography: A method for the study of inclusions and mineralogical texture of large size geological polished thin sections

The nuclear analytical method of element mapping in large-sized (several dozen cm2) polished sections of geological samples was worked out. The method includes activation of the sample by bremstrahlung of an electron accelerator using a developed device for uniform sample irradiation. The next step is to obtain a series of digital autoradiograms, which is processed by the program for estimation of the decay dynamics of induced radioactivity for each pixel of the image. The data obtained are converted into a series of metaimages characterizing the distribution of induced radionuclides (measured elements) over the surface of polished thin sections. The results of mapping are in a good agreement with the data of scanning electron microscopy. The developed method is suggested for screening detection of element distribution including distinguishing of the sample zones containing PGE inclusions.

Efficacy of an automated ultraviolet C device in a shared hospital bathroom.

Toilet flushing can contribute to disease transmission by generating aerosolized bacteria and viruses that can land on nearby surfaces or follow air currents. Aerobic and anaerobic bacterial bioaerosol loads, and bacterial counts on 2 surfaces in a bathroom with a permanently installed, automated ultraviolet C (UVC) irradiation device, were significantly lower than in a comparable bathroom without the UVC device. Permanently installed UVC lights may be a useful supplementary decontamination tool in shared patient bathrooms.

S1-Guidelines on UV phototherapy and photochemotherapy.

Known in part since antiquity, the salutary effects of sunlight again garnered increasing attention in the second half of the 19(th) century. The development of a device for ultraviolet irradiation of cutaneous tuberculosis by Finnsen at the onset of the twentieth century truly marked the beginning of modern phototherapy. In dermatology, treatment methods almost exclusively use wavelengths below the visible light range (ultraviolet light). Since the early 1970s, increasingly powerful artificial light sources have become available for UVB and UVA therapy as well as the combination of UVA and photosensitizers (photochemotherapy). High structural and procedural quality standards are an essential prerequisite for the implementation of effective as well as safe phototherapy. The following guidelines outline the current consensus of leading experts in the field of phototherapy with respect to indications, contraindications, and side effects of various treatment options available. Particular focus is also on adequate UV doses at the beginning and over the further course of treatment as well as on management of side effects.

Design description and validation results for the IFMIF High Flux Test Module as outcome of the EVEDA phase

During the Engineering Validation and Engineering Design Activities (EVEDA) phase (2007-2014) of the International Fusion Materials Irradiation Facility (IFMIF), an advanced engineering design of the High Flux Test Module (HFTM) has been developed with the objective to facilitate the controlled irradiation of steel samples in the high flux area directly behind the IFMIF neutron source. The development process addressed included manufacturing techniques, CAD, neutronic, thermal-hydraulic and mechanical analyses complemented by a series of validation activities. Validation included manufacturing of 1:1 parts and mockups, test of prototypes in the FLEX and HELOKA-LP helium loops of KIT for verification of the thermal and mechanical properties, and irradiation of specimen filled capsule prototypes in the BR2 test reactor. The prototyping activities were backed by several R&D studies addressing focused issues like handling of liquid NaK (as filling medium) and insertion of Small Specimen Test Technique (SSTT) specimens into the irradiation capsules. This paper provides an up-todate design description of the HFTM irradiation device, and reports on the achieved performance criteria related to the requirements. Results of the validation activities are accounted for and the most important issues for further development are identified.

Thermal Stability of Conduction-Cooled HTS Magnets for Rotating Gantry

Carbon ion cancer therapy is becoming more widespread due to its high curative effects and low burden on patients. In particle cancer therapy, it is desirable that the treatment beam irradiates the tumor from different directions in order to reduce the dose on normal cells. A rotating gantry is a suitable apparatus for meeting this requirement. Since the irradiation device orbits a patient inside the gantry, the beam can irradiate the tumor from any direction without changing the posture of the patient. Rotating gantries are already commonly used for proton cancer therapy. On the other hand, those designed for carbon ion cancer therapy have not yet been adopted because they are too large and heavy for installation in general hospitals. An R&D project to reduce the size of a rotating gantry for carbon ion cancer therapy by applying high-temperature superconducting (HTS) magnets is now in progress. It is difficult to use a coolant for the magnets mounted on the rotating gantry because they are rotating. Therefore, conduction cooling should be employed. On the other hand, the magnetic field generated by the magnets of the rotating gantry should be changed depending on the energy of the carbon ion beam in raster-scanning irradiation, and there is some possibility that the carbon ion beam will collide with the coils. This causes anomalous thermal inputs, such as those due to ac loss and beam loss, resulting in the problem of poor thermal stability of the conduction-cooled HTS coils heated by such thermal inputs. Therefore, it is important to estimate the thermal stability of the conduction-cooled HTS coils correctly. In this paper, a saddle-shaped HTS coil was designed, and the thermal runaway current of the HTS coil was numerically simulated.

Plasma-on-chip device for stable irradiation of cells cultured in media with a low-temperature atmospheric pressure plasma

We have developed a micro electromechanical systems (MEMS) device which enables plasma treatment for cells cultured in media. The device, referred to as the plasma-on-chip, comprises microwells and microplasma sources fabricated together in a single chip. The microwells have through-holes between the microwells and microplasma sources. Each microplasma source is located on the backside of each microwells. The reactive components generated by the microplasma sources pass through the through-holes and reach cells cultured in the microwells. In this study, a plasma-on-chip device was modified for a stable plasma treatment. The use of a dielectric barrier discharge (DBD) technique allowed a stable plasma treatment up to 3 min. The plasma-on-chip with the original electrode configuration typically had the maximum stable operation time of around 1 min. Spectral analysis of the plasma identified reactive species such as O and OH radicals that can affect the activity of cells. Plasma treatment was successfully performed on yeast (Saccharomyces cerevisiae) and green algae (Chlorella) cells. While no apparent change was observed with yeast, the treatment degraded the activity of the Chlorella cells and decreased their fluorescence. The device has the potential to help understand interactions between plasma and cells.

Studies of a photochromic model system using NMR with ex-situ and in-situ irradiation devices.

The switching behavior of a photochromic model system was investigated in detail via NMR spectroscopy in order to improve understanding of the compound itself and to provide ways to obtain insights into composition trends of a photo switchable (polymeric) material containing spiropyran/merocyanine units. In addition to the classical irradiation performed outside the magnet (ex-situ), a device for irradiation inside the NMR spectrometer (in-situ) was tested. Both setups are introduced, their advantages and disadvantages as well as their limits are described and the setup for future investigations of photochromic materials is suggested. The influence of different sample concentrations, irradiation procedures, and light intensities on the model system was examined as well as the dependence on solvent, temperature, and irradiation wavelengths. Using the recently published LED illumination device, it was even possible to record two-dimensional spectra on this model system with rather short half-life (7 min in DMSO). This way (13) C chemical shifts of the merocyanine form were obtained, which were unknown before. Copyright © 2016 John Wiley & Sons, Ltd.

Plant irradiation device in microwave field with controlled environment

Plant irradiation during the germination period, by using environmental low level microwave radiation (known as electrosmog) alters the plant germination and the growing process. In order to analyze if such a subtle effect is generated only by the microwave irradiation, the environmental parameters (light, temperature, and humidity) must be kept identical for the reference and the irradiated lot. This is a difficult task because the humidity and temperature are interrelated. In order to study the plant behavior under microwaves low power irradiation, the paper describes the design, manufacturing and operating process and device performances on plant growth. To this end, a low power microwave field (average microwaves power density of 3.8mW/m2) under controlled environmental parameters is used. The device consists of a reference chamber (R) and a microwave irradiation chamber (I), of 0.5m3 volume each one, equipped with access doors. The irradiation chamber ensures microwave field distribution with programmable power, frequency and bandwidth in the most commonly used standards for network communication such as: Global System for Mobile Communications (GSM900/1800), Code Division Multiple Access (CDMA), the third generation of mobile telecommunications technology (3G) or 2.4/5GHz Wireless Local Area Network (WLAN). Both chambers provide a radiofrequency (RF) shielding (at least −60dB) against and toward outside, so the electrosmog is shielded and does not interfere with the inner environment. Both chambers are equipped with performing temperature/humidity sensors and controlled LED lighting system (maximum 400μmolcm−2s−1) with a uniformity of ±5μmolcm−2s−1 measured at the bottom level of the chamber. An embedded system (microcontroller) measures the temperature and humidity and proceeds continuously to match the humidity into the chambers pair with less than ±1.5% relative humidity (RH) difference, by using a low flux exhaust ventilation process through a simple innovative method. The accuracy of the temperature measurement is better than ±0.2°C. Humidity and temperature data set are logged (with programmable acquisition rate) during the whole experiment and can be read later by a personal computer. To identify the influence of microwave treatment on bean seeds and plants development, three growing experiments were settled, based on 122 bean seeds each. The number of germinated seeds (determined each day during 8days of experiment), the germination energy (GE [%]) of the seeds, the length of stems (SL) and roots (RL), the germination (G) [%], the seedling vigor index (SVI) and dry matter content (DM%) have been measured and computed. The obtained data showed significant increase for all parameters on microwave irradiation condition.

Corneal stromal demarcation line after accelerated crosslinking using continuous and pulsed light

To evaluate and compare the depth of corneal stromal demarcation line after accelerated collagen crosslinking (CXL) using continuous and pulsed light ultraviolet-A (UVA) exposure. Department of Ophthalmology, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy. Retrospective case series. Patients with progressive keratoconus were assigned to 1 of 2 treatment protocols using the same irradiation device for accelerated CXL. Patients assigned to Group A received accelerated CXL using continuous UVA light exposure at 30 mW/cm(2) for 4 minutes. Patients assigned to Group B received accelerated CXL using pulsed UVA light with 8 minutes (1 second on/1 second off) of UVA exposure at 30 mW/cm(2) and energy dose of 7.2 J/cm(2). One month after surgery, corneal stromal demarcation line depth was measured by 2 independent observers using anterior segment optical coherence tomography (AS-OCT). A total of 60 patients were assessed. Corneal stromal demarcation line was easily identified on AS-OCT scans in all eyes by both observers. The mean depth of stromal demarcation line was 149.32 ± 36.03 μm in Group A and 213 ± 47.38 μm in Group B. The difference in stromal demarcation line depth between groups was statistically significant (P < .001). Using accelerated CXL, the corneal stromal demarcation line was significantly deeper using pulsed rather than continuous light exposure. No author has financial or proprietary interest in any material or method mentioned.

Abstract 4458: The HIV-derived protein Vpr52-96 has anti-glioma activity in vitro and in vivo

Abstract Background: Patients with actively replicating human immunodeficiency virus (HIV) are highly radiosensitive and exhibit adverse reactions even at low irradiation doses. A major underlying cause is high intra- and extracellular levels of a virus-encoded peptide termed viral protein R (Vpr). As Vpr efficiently crosses the blood-brain barrier and accumulates in astrocytes, we examined whether it may be utilized as a drug in the treatment of glioblastoma multiforme (GBM). Methods: Four glioblastoma-derived cell lines with and without lentivirus-mediated Methylguanine-DNA methyltransferase (MGMT) overexpression (U251, U87, U251-MGMT, U87-MGMT) were exposed to Vpr, temozolomide (TMZ), conventional photon irradiation (2-6 Gy) or to combinations. Caspase assays were employed to detect apoptosis. Colony formation assays were used to analyse clonogenic survival. Dose escalation was performed using n = 12 NOD/SCID/γc−/− (NSG) mice in a classical 3+3 manner. This strain was also used as an orthotopic implant model of glioma using luciferase-expressing U87 cells (n = 18). Continuous Vpr administration was achieved using osmotic pumps, irradiation (3×5 Gy) was performed using a small-animal irradiation device and intracerebral tumor growth was monitored using repetitive contrast-enhanced micro CT scans. Results: Vpr showed high rates of acute toxicities with a LD50 of 4.0±1.1 μM for U251 and a LD50 of 15.7±7.5 μM for U87 cells. Caspase assays revealed Vpr-induced apoptosis in U251 but not in U87 cells. Vpr also efficiently inhibited clonogenic survival both in U251 and U87 cells and showed additive effects with irradiation. In contrast to TMZ, Vpr acted independently of the MGMT expression status. Dose escalation in mice (n = 12) was feasible and resulted in no evident renal or liver toxicity. Similar to irradiation with 3 × 5 Gy (n = 8), Vpr treatment of orthotopically implanted NSG mice (n = 5) delayed tumor growth and significantly (p = 0.041; log-rank test) prolonged overall survival compared to untreated animals (n = 5). Conclusion: The HIV-encoded peptide Vpr exhibits all properties of an effective chemotherapeutic drug and may be a useful agent in the treatment of GBM. Citation Format: Jens Kuebler, Stefanie Kirschner, Linda Hartmann, Grit Welzel, Maren Engelhardt, Carsten Herskind, Marlon R. Veldwijk, Christian Schultz, Manuela Felix, Gerhard Glatting, Patrick Maier, Frederik Wenz, Marc A. Brockmann, Frank A. Giordano. The HIV-derived protein Vpr52-96 has anti-glioma activity in vitro and in vivo. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4458. doi:10.1158/1538-7445.AM2015-4458

Tribological properties of self-assembled monolayers prepared on titanium film

The self-assembled monolayers of octadecyltrichlorosilane (OTS) and 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane (FOTS) were prepared on titanium surfaces, irradiated by ultraviolet irradiation device. Contact angle meter, atomic force microscope and Centre for Tribology (CETR) UMT-2 tribometer were used to explore the surface morphology and tribological properties. The influences of function groups, slide velocity, load and ultraviolet irradiation on tribological properties of samples were analysed. From experiments, it was found that OTS and FOTS SAMs (self-assembled monolayers) prepared on titanium films exhibit hydrophobic and tribological properties, especially under 5-minute ultraviolet irradiation. The frictional force of OTS SAMs is lower than that of FOTS SAMs. The wear time of FOTS SAMs is longer than that of OTS SAMs.

On Line Neutron Flux Mapping in Fuel Coolant Channels of a Research Reactor

This work deals with the on-line neutron flux mapping of the OPAL research reactor. A specific irradiation device has been set up to investigate fuel coolant channels using subminiature fission chambers to get thermal neutron flux profiles. Experimental results are compared to first neutronic calculations and show good agreement (C/E $\sim 0.97$ ).

Determination of the accuracy for targeted irradiations of cellular substructures at SNAKE

In the last 10years the ion microbeam SNAKE, installed at the Munich 14MV tandem accelerator, has been successfully used for radiobiological experiments by utilizing pattern irradiation without targeting single cells. Now for targeted irradiation of cellular substructures a precise irradiation device was added to the live cell irradiation setup at SNAKE. It combines a sub-micrometer single ion irradiation facility with a high resolution optical fluorescence microscope. Most systematic errors can be reduced or avoided by using the same light path in the microscope for beam spot verification as well as for and target recognition. In addition online observation of the induced cellular responses is possible. The optical microscope and the beam delivering system are controlled by an in-house developed software which integrates the open-source image analysis software, CellProfiler, for semi-automatic target recognition.In this work the targeting accuracy was determined by irradiation of a cross pattern with 55MeV carbon ions on nucleoli in U2OS and HeLa cells stably expressing a GFP-tagged repair protein MDC1. For target recognition, nuclei were stained with Draq5 and nucleoli were stained with Syto80 or Syto83. The damage response was determined by live-cell imaging of MDC1-GFP accumulation directly after irradiation. No systematic displacement and a random distribution of about 0.7μm (SD) in x-direction and 0.8μm (SD) in y-direction were observed. An independent analysis after immunofluorescence staining of the DNA damage marker yH2AX yielded similar results.With this performance a target with a size similar to that of nucleoli (i.e. a diameter of about 3μm) is hit with a probability of more than 80%, which enables the investigation of the radiation response of cellular subcompartments after targeted ion irradiation in the future.

Coupled interactions between tungsten surfaces and transient high-heat-flux deuterium plasmas

Fundamental studies on the interactions between transient deuterium-plasma heat pulses and tungsten surfaces were carried out in terms of electrical, mechanical and thermal response in a compact plasma device AIT-PID (Aichi Institute of Technology-Plasma Irradiation Device). Firstly, electron-emission-induced surface-temperature increase is discussed in the surface-temperature range near tungsten's melting point, which is accomplished by controlling the sheath voltage and power transmission factor. Secondly, anomalous penetration of tungsten atomic efflux into the surrounding plasma was observed in addition to a normal layered population; it is discussed in terms of the effect of substantial tungsten influx into the deuterium plasma, which causes dissipation of plasma electron energy. Thirdly, a momentum input from pulsed plasma onto a tungsten target was observed visually. The force is estimated numerically by the accelerated ion flow to the target as well as the reaction of tungsten-vapour efflux. Finally, a discussion follows on the effects of the plasma heat pulses on the morphology of tungsten surface (originally a helium-induced ‘fuzzy’ nanostructure). A kind of bifurcated effect is obtained: melting and annealing. Open questions remain for all the phenomena observed, although sheath-voltage-dependent plasma-heat input may be a key parameter. Discussions on all these phenomena are provided by considering their implications to tokamak fusion devices.

Np-237在AP1000首循环堆芯中的嬗变研究

核电站所产生的乏燃料中含有大量的放射性核素，主要包括长寿命裂变产物(LLFP)和少量锕系元素(MA)，这些核素要通过上万年的衰变才能消除放射性危害。分离嬗变技术(P&T)是将这些放射性核素从乏燃料中分离出来，放入特定装置中，对其进行中子照射，使其转变成低放射性核素或稳定核素。镎(Np)作为一种最主要的MA核素，其含量高，半衰期长。本文利用MCNP程序搭建AP1000反应堆堆芯模型，以二氧化镎(NpO2)嬗变棒为引入方式，设计出在首循环堆芯中添加嬗变材料的10种方案。通过计算比较各种方案中有效增殖因子(keff)、二氧化镎的添加质量和使堆芯重新达到临界所需要改变堆芯的程度，结果显示在堆芯燃料富集度为4.45%区域添加二氧化镎涂层的方案具有优势，本文对该方案进行了分析并进行了优化。 The spent fuel generated by nuclear power plants contains large quantities of radionuclides, in-cluding long-lived fission products (LLFP) and minor actinides (MA). These nuclides decay to no harm through thousands of years. Partitioning and transmutation technology (P&T) is to separate these nuclides from the spent fuel into specific device for neutron irradiation, making it into a low-level radioactive nuclides or stable nuclides. As a major MA nuclide, neptunium (Np) has a high productivity and long half-time. In this paper, MCNP code is used to build the AP1000 reactor core model, and neptunium dioxide (NpO2) transmutation rod is introduced to design 10 schemes where transmutation material is putted into the first cycle core. By calculation and comparing the effective multiplication factor (keff), the added quality of neptunium dioxide and the changing extent to make the core reach the critical again, the result shows that the scheme where neptunium dioxide coating is putted in the fuel enrichment 4.45% of the core has advantages. This paper analyzes the scheme and optimized.

Comparison of calculated results with NTD measured data for establishment of burned core model for Monte Carlo simulation of HANARO reactor

The modeling method to establish a depleted-core model for the Monte Carlo simulation was verified by comparing the analysis results with the neutron flux distribution obtained by a zirconium activation method and a reaction rate of 30Si(n, γ) 31Si obtained using a resistivity measurement method. First, the modeling method used to build the depleted-core model using the HANAFMS core management system is explained. Calculation and measurement methods are also described including the reactor condition, irradiation device, and data treatment methodology. Finally, the viability of the proposed modeling method was discussed through a comparison of the calculated and measured results.

중성자 조사된 SiC Schottky Diode의 온도 의존 특성

The temperature dependent characteristics on the properties of SiC Schottky Diode has been investigated. In this study, the temperature dependent current-voltage characteristics of the SiC Schottky diode were measured in the range of 300 ∼ 500 K. Divided into pre- and post- irradiated device was measured. The barrier height after irradiation device at 500 K increased 0.15 eV compared to 300 K, the barrier height of pre- neutron irradiated Schottky diode increased 0.07 eV. The effective barrier height after irradiation increased from 0.89 eV to 1.05 eV. And ideality factor of neutron irradiated Schottky diode at 500 K decreased 0.428 compared to 300 K, the ideality factor of pre- neutron irradiated Schottky diode decreased 0.354. Also, a slight positive shift in threshold voltage from 0.53 to 0.68 V. we analyzed the effective barrier height and ideality factor of SiC Schottky diode as function of temperature.

Commissioning of the New Irradiation Device for Neutron Transmutation Doping

The LVR-15 reactor is a 10 MW tank type multi-purpose research reactor. The reactor is utilized for production of a wide scale of isotopes with the main focus on generators, testing of materials and chemical regimes of coolant in irradiation rigs and experimental loops (in-pile and out of pile), beam experiments and neutron transmutation doping. The current capacity for neutron transmutation doping was one irradiation facility dedicated to maximum 3 inch ingots. Recently, this capacity was increased by a new irradiation device. Although, the current market demand for neutron transmutation doping is for ingots with diameters up to 6 inch, occasionally even 10 inch, the new device was designed for smaller ingots. The main reason for having a 4 inch diameter maximum for this new device was the limited space in the reactor core. For commissioning purposes of the irradiation channel and for repetitive verification of irradiation parameters special dummy ingots were developed. These dummies can be equipped with three sets of activation detectors, so that the neutron fluence across the ingot can be determined. Within the commissioning, two sets of measurements using the dummy ingots were performed. The primary purpose of these measurements was to verify axial positioning of the irradiation device. The first measurement revealed some issues with accurate positioning of the irradiation device. After these issues were fixed, a new set of measurements using dummy ingots was performed. As a result of these measurements, an estimation of optimal irradiation position was refined. For this refined position a set of silicon ingots was irradiated. From the irradiation results of these ingots, a calibration of the online monitoring system could be done. The successful irradiation of this set of silicon ingots was the last test of the device commissioning; the positioning of the irradiation device and its performance was verified.

Dimensional Measurements Under High Radiation With Optical Fibre Sensors Based on White Light Interferometry - Report on Irradiation Tests

Optical fibre sensors (OFS) can bring substantial advantages over conventional sensing approaches for in- situ measurement in fission Material Testing Reactors (MTRs) and other nuclear research or industrial facilities: easy remote sensing, possibilities of multiplexing, passive operation, low sensitivity to electromagnetic interference, compact size, high resolution and accuracy even under high radiation dose and high temperature, once necessary adaptations have been achieved. In this paper firstly we remind the three undesired effects of high level of irradiation on OFS: radiation induced attenuation, radio luminescence and compaction due to fast neutrons. Then we present two types of sensor that we develop: elongation Fabry Perot sensor - jointly with SCK·CEN - and Michelson type displacement sensor; they both rely on white light interferometry to retrieve the desired measurement. We report the results of irradiation of Fabry-Perot sensors in the core of BR2 material testing reactor in Mol (Belgium), under intense neutron-gamma flux and at high temperature. Six Fabry Perot fibre optics sensors are mounted on a support insensitive to radiation. The objective is to test the survival and the drift of the sensors. The temperature is maintained steady at 200°C during 22 days then the temperature is increased up to 390°C. Among five sensors built according to nominal scheme, four are still alive at the end of the cycle and three show a low drift of 1 to 4 μm. These results show a clear progress compared to the previous irradiation and make it possible to consider the use of these sensors in real tests of material in MTR reactor. However, improvement in the robustness of the interfaces is still necessary. The next part is devoted to the measurement of displacements perpendicular to the direction of the lead-in fibre, of interest for small room environments where the fibre cannot make a 90° turn. The optical scheme is based on the Michelson interferometer. The fibre and signal conditioner are the same as used with the Fabry Perot extensometer. The sensor is expected to be applied for the measurement of variations in the diameter of the fuel cladding during exposure in a research reactor. Three sensors arranged on a circle, within 120° from each other, must measure displacements of the external surface of the cladding with an error lower than 10 μm, over a 0.5 mm range. The irradiation device considered is in development for the Jules Horowitz Reactor (RJH) under construction in Cadarache (France). We have developed and tested up to 400°C the optical module which will be inserted in the mechanical part comprising the mechanical probe. With a bit larger room available, we also develop a device capable of measuring displacement, under high nuclear flux in the vicinity of the core of Sodium Fast Reactor. The objective could be to sense more or less directly the deformation of the core support structure and core movement. The uncertainty expected is near 1 μm with a range of more than 10 mm.

Evaluation of Corneal Stromal Demarcation Line Depth Following Standard and a Modified-Accelerated Collagen Cross-linking Protocol

To compare the corneal stromal demarcation line depth using anterior segment optical coherence tomography (AS-OCT) after corneal collagen cross-linking (CXL) using 2 different treatment protocols: the standard Dresden protocol (30 minutes with 3 mW/cm(2)) and a modified-accelerated protocol (14 minutes with 9 mW/cm(2)). Prospective, comparative study. Forty-three keratoconic patients (52 eyes) were enrolled. All patients underwent CXL using the same high-intensity ultraviolet-A (UV-A) irradiation device. Twenty-six eyes were treated for 30 minutes with 3 mW/cm(2) according to the standard Dresden protocol (Group 1), while 26 eyes were treated with a novel modified-accelerated CXL protocol for 14 minutes with 9 mW/cm(2) of UV-A irradiation intensity (Group 2). One month postoperatively, corneal stromal demarcation line depth was measured by 2 independent observers using AS-OCT. Corneal stromal demarcation line depth was assessed with no significant difference between observer measurements for both groups (P = .676 for Group 1 and P = .566 for Group 2). Mean corneal stromal demarcation line depth was 337.00 ± 46.46 μm for Group 1 and 322.91 ± 48.28 μm for Group 2. There was no statistically significant difference (P = .243) in the corneal stromal demarcation line depth between the 2 groups. Corneal stromal demarcation line depth using UV-A with 3 mW/cm(2) for 30 minutes and 9 mW/cm(2) for 14 minutes was similar. A modified-accelerated protocol of 14 minutes of CXL provided the same treatment depth as the classic Dresden protocol.