Raster Scanning Technique Research Articles

Evaluation of Helium Ion Radiotherapy in Combination with Gemcitabine in Pancreatic Cancer In Vitro.

Pancreatic cancer is one of the most aggressive and lethal cancers. New treatment strategies are highly warranted. Particle radiotherapy could offer a way to overcome the radioresistant nature of pancreatic cancer because of its biological and physical characteristics. Within particles, helium ions represent an attractive therapy option to achieve the highest possible conformity while at the same time protecting the surrounding normal tissue. The aim of this study was to evaluate the cytotoxic efficacy of helium ion irradiation in pancreatic cancer in vitro. Human pancreatic cancer cell lines AsPC-1, BxPC-3 and Panc-1 were irradiated with photons and helium ions at various doses and treated with gemcitabine. Photon irradiation was performed with a biological cabin X-ray irradiator, and helium ion irradiation was performed with a spread-out Bragg peak using the raster scanning technique at the Heidelberg Ion Beam Therapy Center (HIT). The cytotoxic effect on pancreatic cancer cells was measured with clonogenic survival. The survival curves were compared to the predicted curves that were calculated via the modified microdosimetric kinetic model (mMKM). The experimental relative biological effectiveness (RBE) of helium ion irradiation ranged from 1.0 to 1.7. The predicted survival curves obtained via mMKM calculations matched the experimental survival curves. Mainly additive cytotoxic effects were observed for the cell lines AsPC-1, BxPC-3 and Panc-1. Our results demonstrate the cytotoxic efficacy of helium ion radiotherapy in pancreatic cancer in vitro as well as the capability of mMKM calculation and its value for biological plan optimization in helium ion therapy for pancreatic cancer. A combined treatment of helium irradiation and chemotherapy with gemcitabine leads to mainly additive cytotoxic effects in pancreatic cancer cell lines. The data generated in this study may serve as the radiobiological basis for future experimental and clinical works using helium ion radiotherapy in pancreatic cancer treatment.

Patterns of Temporal Lobe Reaction and Radiation Necrosis after Particle Radiotherapy in Patients with Skull Base Chordoma and Chondrosarcoma-A Single-Center Experience.

The current study aims to evaluate the occurrence of temporal lobe reactions and identify possible risk factors for patients who underwent particle therapy of the skull base. 244 patients treated for skull base chordoma (n = 144) or chondrosarcoma (n = 100) at the Heidelberg Ion Beam Therapy Center (HIT) using a raster scan technique, were analyzed. Follow-up MRI-scans were matched with the initial planning images. Radiogenic reactions were contoured and analyzed based on volume and dose of treatment. 51 patients with chordoma (35.4%) and 30 patients (30%) with chondrosarcoma experienced at least one temporal lobe reaction within the follow-up period (median 49 months for chondrosarcoma, 62 months for chordoma). Age, irradiated volume, and dose values were significant risk factors for the development of temporal lobe reactions with the highest significance for the value of DMax-7 being defined as the dose maximum in the temporal lobe minus the 7cc with the highest dose (p = 0.000000000019; OR 1.087). Temporal lobe reactions are a common side effect after particle therapy of the skull base. We were able to develop a multivariate model, which predicted radiation reactions with a specificity of 99% and a sensitivity of 52.2%.

Measuring capillary flow dynamics using interlaced two-photon volumetric scanning

Two photon microscopy and optical coherence tomography (OCT) are two standard methods for measuring flow speeds of red blood cells in microvessels, particularly in animal models. However, traditional two photon microscopy lacks the depth of field to adequately capture the full volumetric complexity of the cerebral microvasculature and OCT lacks the specificity offered by fluorescent labeling. In addition, the traditional raster scanning technique utilized in both modalities requires a balance of image frame rate and field of view, which severely limits the study of RBC velocities in the microvascular network. Here, we overcome this by using a custom two photon system with an axicon based Bessel beam to obtain volumetric images of the microvascular network with fluorescent specificity. We combine this with a novel scan pattern that generates pairs of frames with short time delay sufficient for tracking red blood cell flow in capillaries. We track RBC flow speeds in 10 or more capillaries simultaneously at 1 Hz in a 237 µm × 237 µm × 120 µm volume and quantified both their spatial and temporal variability in speed. We also demonstrate the ability to track flow speed changes around stalls in capillary flow and measure to 300 µm in depth.

Proton and carbon ion beam treatment with active raster scanning method in 147 patients with skull base chordoma at the Heidelberg Ion Beam Therapy Center—a single-center experience

BackgroundThis study aimed to compare the results of irradiation with protons versus irradiation with carbon ions in a raster scan technique in patients with skull base chordomas and to identify risk factors that may compromise treatment results.MethodsA total of 147 patients (85 men, 62 women) were irradiated with carbon ions (111 patients) or protons (36 patients) with a median dose of 66 Gy (RBE (Relative biological effectiveness); carbon ions) in 4 weeks or 74 Gy (RBE; protons) in 7 weeks at the Heidelberg Ion Beam Therapy Center (HIT) in Heidelberg, Germany. The median follow-up time was 49.3 months. All patients had gross residual disease at the beginning of RT. Compression of the brainstem was present in 38%, contact without compression in 18%, and no contact but less than 3 mm distance in 16%. Local control and overall survival were evaluated using the Kaplan–Meier Method based on scheduled treatment (protons vs. carbon ions) and compared via the log rank test. Subgroup analyses were performed to identify possible prognostic factors.ResultsDuring the follow-up, 41 patients (27.9%) developed a local recurrence. The median follow-up time was 49.3 months (95% CI: 40.8–53.8; reverse Kaplan–Meier median follow-up time 56.3 months, 95% CI: 51.9–60.7). No significant differences between protons and carbon ions were observed regarding LC, OS, or overall toxicity. The 1‑year, 3‑year, and 5‑year LC rates were 97%, 80%, and 61% (protons) and 96%, 80%, and 65% (carbon ions), respectively. The corresponding OS rates were 100%, 92%, and 92% (protons) and 99%, 91%, and 83% (carbon ions). No significant prognostic factors for LC or OS could be determined regarding the whole cohort; however, a significantly improved LC could be observed if the tumor was > 3 mm distant from the brainstem in patients presenting in a primary situation.ConclusionOutcomes of proton and carbon ion treatment of skull base chordomas seem similar regarding tumor control, survival, and toxicity. Close proximity to the brainstem might be a negative prognostic factor, at least in patients presenting in a primary situation.

Deep-Learning Assisted Control of Optical Phased Array: A Case Study

Modern raster scanning techniques and single pixel applications require a precise control of the field profiles radiated by Optical Phased Arrays, which can be controlled by external electrical signals modifying the optical paths inside these devices. In particular for single pixel imaging solutions, it is generally not straightforward to identify the control signals required to generate the desired far field pattern. We propose therefore a Convolutional Neural Network based approach which allows a user to determine the signals required to accurately reproduce an arbitrary far field profile.

Carbon ion radiotherapy as definitive treatment in locally recurrent pancreatic cancer

PurposeData on management of locally recurrent pancreatic cancer (LRPC) after primary resection are limited. Recently, surprisingly high overall survival rates were reported after irradiation with carbon ions. Here, we report on our clinical experience using carbon ion radiotherapy as definitive treatment in LRPC at the Heidelberg Ion-Beam Therapy Center (HIT).MethodsBetween 2015 and 2019, we treated 13 patients with LRPC with carbon ions with a median total dose of 48 Gy (RBE) in 12 fractions using an active raster-scanning technique at a rotating gantry. No concomitant chemotherapy was administered. Overall survival, local control, and toxicity rates were evaluated 18 months after the last patient finished radiotherapy.ResultsWith a median follow-up time of 9.5 months, one patient is still alive (8%). Median OS was 12.7 months. Ten patients (77%) developed distant metastases. Additionally, one local recurrence (8%) and two regional tumor recurrences (15%) were observed. The estimated 1‑year local control and locoregional control rates were 87.5% and 75%, respectively. During radiotherapy, we registered one gastrointestinal bleeding CTCAE grade III (8%) due to gastritis. The bleeding was sufficiently managed with conservative therapy. No further higher-grade acute or late toxicities were observed.ConclusionWe demonstrate high local control rates in a rare cohort of LRPC patients treated with carbon ion radiotherapy. The observed median overall survival rate was not improved compared to historical in-house data using photon radiotherapy. This is likely due to a high rate of distant tumor progression, highlighting the necessity of additional chemotherapy.

Ghost imaging second harmonic generation microscopy

Second harmonic generation (SHG) microscopy is useful for visualizing interfaces and sub-structures within a wide range of materials due to the propensity for SHG to occur in non-centrosymmetric environments. However, since SHG is a nonlinear process generally necessitating small focal sizes for higher peak powers, a raster scanning approach is usually needed to build an SHG image over a significant sample size. While raster scanning is effective, there is a cost in terms of the time needed to acquire the image and, also, some materials cannot withstand the higher optical intensities within the small focal volume. In order to address this, we describe a SHG microscopy approach based on ghost imaging (GI), which enables imaging data to be collected in parallel rather than sequentially as in raster scanning techniques. We experimentally demonstrate the approach and combine GI-SHG with compressive sensing to make further substantial gains in reducing the amount of sampling required for image reconstruction. Furthermore, GI-SHG is shown to have significant advantages for imaging in highly scattering environments, partly because GI is a background-free approach requiring spatial correlations between photons that travel two paths, with one path entirely devoid of sample interaction. This basic property of GI means that only the photons that travel unimpeded through the sample preserve the spatial correlations needed to reconstruct the image, while more scattered photons do not contribute to the overall GI signal. Finally, we compare the image quality and sampling properties of three different reconstruction algorithms used for compressive sensing.

Active-Scanned Protons and Carbon Ions in Cancer Treatment of Patients With Cardiac Implantable Electronic Devices: Experience of a Single Institution.

Background: Ionizing radiation was shown to be able to influence the function of cardiac implantable electronic devices (CIED's) leading to malfunctions with potentially severe consequences. Those effects presumably correlate with beam energy and neutron production. Thus, particle facilities are commonly cautious to treat patients with CIED's with particles, but substantial evidence is lacking.Methods and Materials: In total 31 patients were investigated, who have been treated at the Heidelberg Ion-Beam Therapy Center (HIT) from September 2012 to February 2019 with protons and carbon ions in active-scanning technique. All CIED's were checked after every single irradiation by the department of cardiology. The minimum distance between the CIED and the planning target volume (PTV), the 10% isodose and the single beam in Beam's Eye View (BEV) was analyzed for 12 patients.Results: In total, 31 patients received 32 courses of radiotherapy (RT). Twenty-two received treatment with carbon ion beam and ten with proton beam. The cumulative number of fractions was 582, the cumulative number of documented controls after RT was 504 (87%). Three patients had an implantable cardioverter-defibrillator (ICD) and 28 patients had a pacemaker at the time of treatment. Seven patients had a heart rate of ≤30/min. The majority of patients (69%) were treated for tumors of the head and neck. The median minimum distance between CIED and PTV, 10% isodose and the single beam on BEV was 13.4, 11.6, and 8.3 cm, respectively. There were no registered events associated with the treatment in this evaluation.Conclusion: Treatment of CIED-patients with protons and carbon ions applied with active raster scanning technique was safe without any incidents in our single center experience. Monitoring after almost every fraction provided systematic and extensive data. Further investigations are necessary in order to form reliable guidelines, which should consider different modes of beam application, as active scanning supposedly provides a greater level of safety from malfunctions for patients with CIED undergoing particle irradiation.

Carbon-ion radiotherapy in accelerated hypofractionated active raster-scanning technique for malignant lacrimal gland tumors: feasibility and safety.

IntroductionWe evaluated treatment outcomes of CIRT in an active raster-scanning technique alone or in combination with IMRT for lacrimal gland tumors.MethodsA total of 24 patients who received CIRT for a malignant lacrimal gland tumor at the HIT between 2009 and 2018 were analyzed retrospectively for LC, OS, and distant progression-free survival (DPFS) using Kaplan–Meier estimates. Toxicity was assessed according to the CTCAE version 5.ResultsMedian follow-up was 30 months and overall median LC, OS, and DPFS 24 months, 36 months, and 31 months, respectively. Two-year LC, OS, and DPFS of 93%, 96%, and 87% with CIRT was achieved for all patients. Local failure occurred only in patients with ACC and after a median follow-up of 30 months after the completion of RT (n=5, 21%; P=0.09). We identified a significant negative impact of a macroscopic tumor disease, which was diagnosed on planning CT or MRI before RT, on LC (P=0.026). In contrast, perineural spread (P=0.661), T stage (P=0.552), and resection margins in operated patients (P=0.069) had no significant impact on LC. No grade ≥3 acute or grade >3 chronic toxicity occurred. Late grade 3 side effects were identified in form of a wound-healing disorder 3 months after RT in one patient and temporal lobe necrosis 6 months after RT in another (n=2, 8%).ConclusionAccelerated hypofractionated active raster-scanning CIRT for relative radio-resistant malignant lacrimal gland tumors results in adequate LC rates and moderate acute and late toxicity. Nevertheless, LC for ACC histology remains challenging and risk factors for local recurrence are still unclear. Further follow-up is necessary to evaluate long-term clinical outcome.

Improvement of Alternative Non-Raster Scanning Methods for High Speed Atomic Force Microscopy: A Review

The invention of the nanotechnology adds a new branch to investigate and control the physical properties of matters at atomic level. The aim of this technology is to image the characteristics of metals, biological organs, and polymers. Scanning probe microscopy (SPM) opens a new branch to analysis the atomic properties of the matters. Atomic force microscopy (AFM), a branch of SPM, is a versatile tool of nanotechnology to image both conductive and non-conductive matters with high resolution. Commercial AFM uses raster scanning technique to produce image of the matters that is responsible for low scanning speed and image quality. The performances of AFM are hampered due to low bandwidth of the scanning unit and vertical Proportional-Integral (PI) controller and may damage the surface of the samples. Different non-raster scanning techniques such as sinusoidal, rotational, spiral, cycloid, and lissajous scanning have been proposed to overcome the limitations of raster scanning method by providing high scanning speed, image quality, and resolution. This paper presents a survey of raster and non-raster scanning methods for high speed AFM and provides a compression between them in term of scanning speed, bandwidth and highest achievable scanning frequency. The control techniques applied to the AFM for improving raster, sinusoidal, spiral, cycloid, and lissajous scanning methods are studied in this paper to find most optimum scanning technique for AFM.

Terahertz wave near-field compressive imaging with a spatial resolution of over λ/100.

We demonstrate terahertz (THz) wave near-field imaging with a spatial resolution of ∼4.5 μm using single-pixel compressive sensing enabled by femtosecond-laser (fs-laser) driven vanadium dioxide (VO2)-based spatial light modulator. By fs-laser patterning a 180nm thick VO2 nanofilm with a digital micromirror device, we spatially encode the near-field THz evanescent waves. With single-pixel Hadamard detection of the evanescent waves, we reconstructed the THz wave near-field image of an object from a serial of encoded sequential measurements, yielding improved signal-to-noise ratio by one order of magnitude over a raster-scanning technique. Further, we demonstrate that the acquisition time was compressed by a factor of over four with 90% fidelity using a total variation minimization algorithm. The proposed THz wave near-field imaging technique inspires new and challenging applications such as cellular imaging.

Compressive characterization of telecom photon pairs in the spatial and spectral degrees of freedom.

In the past few years, physicists and engineers have demonstrated the possibility of utilizing multiple degrees of freedom of the photon to perform information processing tasks for a wide variety of applications. Furthermore, complex states of light offer the possibility of encoding and processing many bits of information in a single photon. However, the challenges involved in the process of extracting large amounts of information, encoded in photonic states, impose practical limitations to realistic quantum technologies. Here, we demonstrate characterization of quantum correlated photon pairs in the spatial and spectral degrees of freedom. Our technique utilizes a series of random projective measurements in the spatial basis that do not perturb the spectral properties of the photon. The sparsity in the spatial properties of downconverted photons allows us to exploit the potential of compressive sensing to reduce the number of measurements to reconstruct spatial and spectral properties of correlated photon pairs at telecom wavelength. We demonstrate characterization of a photonic state with 12 × 109 dimensions using only 20% of the measurements with respect to the conventional raster scan technique. Our characterization technique opens the possibility of increasing and exploiting the complexity and dimensionality of quantum protocols that utilize multiple degrees of freedom of light with high efficiency.

Clinical outcome after particle therapy for meningiomas of the skull base: toxicity and local control in patients treated with active rasterscanning

BackgroundMeningiomas of the skull base account for 25–30% of all meningiomas. Due to the complex structure of the cranial base and its close proximity to critical structures, surgery is often associated with substantial morbidity. Treatment options include observation, aggressive surgical intervention, stereotactic or conventional radiotherapy.In this analysis we evaluate the outcome of 110 patients with meningiomas of the skull base treated with particle therapy. It was performed within the framework of the “clinical research group heavy ion therapy” and supported by the German Research Council (DFG, KFO 214).MethodsBetween May 2010 and November 2014, 110 Patients with skull base meningioma were treated with particle radiotherapy at the Heidelberg Ion Therapy Center (HIT). Primary localizations included the sphenoid wing (n = 42), petroclival region (n = 23), cavernous sinus (n = 4), sella (n = 10) and olfactory nerve (n = 4). Sixty meningiomas were benign (WHO °I); whereas 8 were high-risk (WHO °II (n = 7) and °III (n = 1)). In 42 cases histology was not examined, since no surgery was performed.Proton (n = 104) or carbon ion (n = 6) radiotherapy was applied at Heidelberg Ion Therapy Center (HIT) using raster-scanning technique for active beam delivery. Fifty one patients (46.4%) received radiotherapy due to tumor progression, 17 (15.5%) after surgical resection and 42 (38.2%) as primary treatment.ResultsMedian follow-up in this analysis was 46,8 months (95% CI 39,9–53,7; Q1-Q3 34,3–61,7). Particle radiotherapy could be performed safely without toxicity-related interruptions. No grade IV or V toxicities according to CTCAE v4.0 were observed. Particle RT offered excellent overall local control rates with 100% progression-free survival (PFS) after 36 months and 96.6% after 60 months. Median PFS was not reached due to the small number of events. Histology significantly impacted PFS with superior PFS after 5 years for low-risk tumors (96.6% vs. 75.0%, p = 0,02). Overall survival was 96.2% after 60 months and 92.0% after 72 months from therapy. Of six documented deaths, five were definitely not and the sixth probably not meningioma-related.ConclusionParticle radiotherapy is an excellent treatment option for patients with meningiomas of the skull base and can lead to long-term tumor control with minimal side effects. Other prospective studies with longer follow-up will be necessary to further confirm the role of particle radiotherapy in skull base meningioma.

Early treatment response of a rare papillary tumor of the pineal region after primary proton-beam therapy using the raster-scanning technique at HIT.

Pineocytomas are rare intracranial tumors occurring in the pineal gland region. The curative therapy of choice is gross total resection, which cannot be performed in all patients because of the frequent eloquent location of these tumors. Percutaneous fractionated radiotherapy is an alternative treatment approach that may result in high local control rates. Nevertheless, our knowledge of this tumor entity is limited and based on retrospective case series only. We present a patient with a papillary tumor of the pineal region who was treated with highly conformal proton-beam therapy at the Heidelberg Ion Therapy Center (HIT) using the raster-scanning technique.

Attosecond transient absorption instrumentation for thin film materials: Phase transitions, heat dissipation, signal stabilization, timing correction, and rapid sample rotation.

We present an extreme ultraviolet (XUV) transient absorption apparatus tailored to attosecond and femtosecond measurements on bulk solid-state thin-film samples, specifically when the sample dynamics are sensitive to heating effects. The setup combines methodology for stabilizing sub-femtosecond time-resolution measurements over 48 h and techniques for mitigating heat buildup in temperature-dependent samples. Single-point beam stabilization in pump and probe arms and periodic time-zero reference measurements are described for accurate timing and stabilization. A hollow-shaft motor configuration for rapid sample rotation, raster scanning capability, and additional diagnostics are described for heat mitigation. Heat transfer simulations performed using a finite element analysis allow comparison of sample rotation and traditional raster scanning techniques for 100 Hz pulsed laser measurements on vanadium dioxide, a material that undergoes an insulator-to-metal transition at a modest temperature of 340 K. Experimental results are presented confirming that the vanadium dioxide (VO2) sample cannot cool below its phase transition temperature between laser pulses without rapid rotation, in agreement with the simulations. The findings indicate the stringent conditions required to perform rigorous broadband XUV time-resolved absorption measurements on bulk solid-state samples, particularly those with temperature sensitivity, and elucidate a clear methodology to perform them.

Optomechanical System Design for Dual-Mode Stand-Off Submillimeter Wavelength Imagers

In this paper, the practical tradeoffs for designing submillimeter wavelength imagers based on optomechanical systems combined with focal plane arrays (FPAs) are presented. The architecture of these systems differs for operation at short and long ranges. General formulas to derive the effective field of view of diffraction limited quasi-optical systems in these two scenarios are shown. These formulas can be used to evaluate the performance of a specific optical system implementation. As an application example, we present the design of an optomechanical system that can operate at both ranges in a modular approach. The presented implementation achieves an effective field of view, which is $\hbox{70}\%$ of the canonical one. The proposed solution consists of a linear FPA of eight active transceivers combined with a raster scan technique. The system for short-range scenario is a side-fed dual-reflector Dragonian architecture because of its good scanning performance when illuminated by an FPA. Thanks to the system's small aperture, the scanner is arranged after the primary mirror, without causing additional scan loss. The Dragonian system is then used to illuminate a confocal dual-reflector architecture to magnify its aperture, and can be used in the long-range scenario. The scanner in this case is before the main aperture and it has to be considered in the performance optimization of the optical system since it adds phase aberration loss.

Diffusion-weighted MRI treatment monitoring of primary hypofractionated proton and carbon ion prostate cancer irradiation using raster scan technique.

To investigate parametric changes in the apparent diffusion coefficient (ADC) at multiple timepoints during and after completion of primary proton and carbon ion irradiation of prostate cancer (PCa) as compared with normal-appearing prostate parenchyma. In all, 92 patients with histologically confirmed PCa received either proton or carbon ion hypofractionated radiotherapy (RT). All were prospectively evaluated with diffusion-weighted magnetic resonance imaging (DWI-MRI) at five timepoints: baseline, day 10 during therapy and 6 weeks, 6 months, and 18 months after treatment. Linear mixed models (LMM) were used to evaluate the effects of radiation, antihormonal therapy, time, and type of particle irradiation on manual ADC measurements. ADC differences related to prostate-specific antigen (PSA) relapse according to PSA thresholds and to Vancouver rules and Phoenix criteria were examined using LMM and unpaired Student's t-test. A measurable and continuous increase of tumor ADC measurements from baseline (1.194 × 10-3 mm2 /s) during (1.350 × 10-3 mm2 /s, day 10, P = 0.006) and after treatment (1.355/1.430/1.490 × 10-3 mm2 /s, week 6 / month 6 / month 18, P = 0.001/<0.001/<0.001) was found. ADC values of normal-appearing control tissue remained unchanged. Androgen deprivation (P ≥ 0.320), different PSA thresholds (P = 0.634), and PSA relapse criteria according to Vancouver rules (P ≥ 0.776) had no effect. A weak association between 18-month measurements and Phoenix criteria (P = 0.046) was found. ADC parametric changes were distinct in tumor tissue, highlighting the ability of diffusion MRI to evaluate different aspects of the microscopic pathophysiology. Although promising, their use as noninvasive imaging biomarkers requires further validation. 1 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:850-860.

Dynamic contrast enhanced MRI monitoring of primary proton and carbon ion irradiation of prostate cancer using a novel hypofractionated raster scan technique

PurposeTo characterize parametric changes measured by sequential dynamic contrast enhanced perfusion MRI (DCE-MRI) during primary proton and carbon ion irradiation of prostate cancer using a novel hypofractionated raster scan technique to determine the potential of pharmacokinetic analysis for monitoring treatment effects of this novel irradiation scheme. Materials and methodsNinety-two patients were evaluated prospectively with DCE-MRI at baseline, day 10 during therapy, and 6weeks, 6months and 18months after treatment completion. After motion correction and co-registration to morphological T2-weighted images, tumors and normal appearing contralateral parenchyma (NACP) were segmented manually on T2W images and ROI statistics calculated for pharmacokinetic parameters Ktrans, kep and ve using the standard Tofts model. ResultsThe volume transfer constant (Ktrans, p<0.001/p=0.010) and the leakage space partial volume (ve, p<0.001/p=0.005) showed a statistically significant increase during therapy with protons and carbon ions, respectively. Parametric increases occurred only in patients naive to antihormonal therapy (AHT), and were maximal 10days after the begining of treatment. The rate constant (kep) showed a significant increase only for proton, but not for carbon irradiation (p=0.021). Statistically significant differences between PC and NACP were observed for all parameters (p<0.001). AHT naïve patients with persistent PSA elevation above 1ng/ml at 12months experienced statistically significant elevation of Ktrans and ve compared to those with PSA suppression (p=0.04/p=0.023). ConclusionDCE parametric changes following ion particle irradiation of the prostate have not been previously reported. Their development into potential non-invasive imaging biomarkers for assessment of treatment response and efficacy is expected to be aided by the data on the magnitude and temporal evolution of parametric responses of cancer and normal tissue during and after therapy presented here, especially the changes of Ktrans and ve during therapy and their different measurement levels within tumors and in normal appearing contralateral tissue.

Lateral resolution enhancement using programmable phase modulator in optical coherence tomography.

Adaptive optics plays an important role in the correction of high-order aberrations to enhance lateral resolution. An OCT system coupled with a programmable phase modulator is designed to verify lateral resolution improvement. The Hamamatsu high-resolution, non-pixelized, optically addressed light modulator (PAL-SLM) PPM X7550 series is used to correct aberrations, utilizing a simple method based on phase information from OCT images. The advantages of this method are its high simplicity and low cost. A raster scanning technique is adopted to scan samples covered with scattering suspension. Metal lines covered with scattering suspension are imaged, and a respective correction is applied to remove the aberration. Results demonstrate an improvement in lateral resolution on metal grid samples.

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