Radiation dose optimized lateral expansion of the field of view in synchrotron radiation X-ray tomographic microscopy

Volumetric data at micrometer level resolution can be acquired within a few minutes using synchrotron-radiation-based tomographic microscopy. The field of view along the rotation axis of the sample can easily be increased by stacking several tomograms, allowing the investigation of long and thin objects at high resolution. On the contrary, an extension of the field of view in the perpendicular direction is non-trivial. This paper presents an acquisition protocol which increases the field of view of the tomographic dataset perpendicular to its rotation axis. The acquisition protocol can be tuned as a function of the reconstruction quality and scanning time. Since the scanning time is proportional to the radiation dose imparted to the sample, this method can be used to increase the field of view of tomographic microscopy instruments while optimizing the radiation dose for radiation-sensitive samples and keeping the quality of the tomographic dataset on the required level. This approach, dubbed wide-field synchrotron radiation tomographic microscopy, can increase the lateral field of view up to five times. The method has been successfully applied for the three-dimensional imaging of entire rat lung acini with a diameter of 4.1 mm at a voxel size of 1.48 microm.

Fluorescent-magnetic hybrid nanoparticles induce a dose-dependent increase in proinflammatory response in lung cells in vitro correlated with intracellular localization

Iron-platinum nanoparticles embedded in a poly(methacrylic acid) (PMA) polymer shell and fluorescently labeled with the dye ATTO 590 (FePt-PMA-ATTO-2%) are investigated in terms of their intracellular localization in lung cells and potential to induce a proinflammatory response dependent on concentration and incubation time. A gold core coated with the same polymer shell (Au-PMA-ATTO-2%) is also included. Using laser scanning and electron microscopy techniques, it is shown that the FePt-PMA-ATTO-2% particles penetrate all three types of cell investigated but to a higher extent in macrophages and dendritic cells than epithelial cells. In both cell types of the defense system but not in epithelial cells, a particle-dose-dependent increase of the cytokine tumor necrosis factor alpha (TNFalpha) is found. By comparing the different nanoparticles and the mere polymer shell, it is shown that the cores combined with the shells are responsible for the induction of proinflammatory effects and not the shells alone. It is concluded that the uptake behavior and the proinflammatory response upon particle exposure are dependent on the time, cell type, and cell culture.

High-dose (80 Gy) intensity-modulated radiation therapy with daily image-guidance as primary treatment for localized prostate cancer

to report acute and late toxicity in prostate cancer patients treated by high-dose intensity-modulated radiation therapy (IMRT) with daily image-guidance.

Urethral toxicity vs. cancer control-Lessons to be learned from high-dose rate brachytherapy combined with intensity-modulated radiation therapy in intermediate- and high-risk prostate cancer

To describe biochemical relapse-free survival (BRFS) and late toxicity after combined high-dose rate brachytherapy (HDR-B) and intensity-modulated radiation therapy (IMRT) in intermediate- and high-risk prostate cancer patients.

Monte Carlo dose calculation improvements for low energy electron beams using eMC

The electron Monte Carlo (eMC) dose calculation algorithm in Eclipse (Varian Medical Systems) is based on the macro MC method and is able to predict dose distributions for high energy electron beams with high accuracy. However, there are limitations for low energy electron beams. This work aims to improve the accuracy of the dose calculation using eMC for 4 and 6 MeV electron beams of Varian linear accelerators. Improvements implemented into the eMC include (1) improved determination of the initial electron energy spectrum by increased resolution of mono-energetic depth dose curves used during beam configuration; (2) inclusion of all the scrapers of the applicator in the beam model; (3) reduction of the maximum size of the sphere to be selected within the macro MC transport when the energy of the incident electron is below certain thresholds. The impact of these changes in eMC is investigated by comparing calculated dose distributions for 4 and 6 MeV electron beams at source to surface distance (SSD) of 100 and 110 cm with applicators ranging from 6 x 6 to 25 x 25 cm(2) of a Varian Clinac 2300C/D with the corresponding measurements. Dose differences between calculated and measured absolute depth dose curves are reduced from 6% to less than 1.5% for both energies and all applicators considered at SSD of 100 cm. Using the original eMC implementation, absolute dose profiles at depths of 1 cm, d(max) and R50 in water lead to dose differences of up to 8% for applicators larger than 15 x 15 cm(2) at SSD 100 cm. Those differences are now reduced to less than 2% for all dose profiles investigated when the improved version of eMC is used. At SSD of 110 cm the dose difference for the original eMC version is even more pronounced and can be larger than 10%. Those differences are reduced to within 2% or 2 mm with the improved version of eMC. In this work several enhancements were made in the eMC algorithm leading to significant improvements in the accuracy of the dose calculation for 4 and 6 MeV electron beams of Varian linear accelerators.

Intensified chemotherapy and dose-reduced involved-field radiotherapy in patients with early unfavorable Hodgkin's lymphoma: final analysis of the German Hodgkin Study Group HD11 trial

Combined-modality treatment consisting of four to six cycles of chemotherapy followed by involved-field radiotherapy (IFRT) is the standard of care for patients with early unfavorable Hodgkin's lymphoma (HL). It is unclear whether treatment results can be improved with more intensive chemotherapy and which radiation dose needs to be applied.

High-dose melphalan with or without stem cell support before myeloablative allo-SCT for remission induction in patients with advanced relapsed or refractory AML

Treatment strategies for relapsed/refractory AML are limited and disappointing. Recently, high-dose melphalan (HDM) chemotherapy and autologous hematopoietic SCT (HSCT) has been proposed for AML re-induction. We investigated the impact of HDM remission induction in highly advanced relapsed/refractory AML patients planned for allogeneic HSCT. A total of 23 patients with relapsed/refractory AML were prospectively scheduled for HDM with or without stem cell support followed by myeloablative allogeneic HSCT. Patients included nine individuals with a history of previous HSCT (seven allogeneic, two autologous). A total of 18 patients (78%) achieved a leukemia-free state and an additional four had substantial reduction of the initial leukemia burden warranting treatment continuation. There were no differences between patients with or without immediate stem cell support regarding mucositis or other organ toxicity. A total of 20 patients proceeded to myeloablative allogeneic HSCT. Outcome of allogeneic HSCT was poor: 11 patients (55%) relapsed, 7 patients (35%) died from TRM and only 2 patients (10%) were alive at the last follow-up. Our study shows that HDM is effective in inducing a leukemia-free state in patients with highly advanced relapsed/refractory AML. Leukemia burden reduction with HDM, however, did not translate into improved OS.

Radiation dose reduction in computer assisted navigation for functional endoscopic sinus surgery--cadaver head experiments and clinical implementation

Computed tomography based navigation for endoscopic sinus surgery is inflationary used despite of major public concern about iatrogenic radiation induced cancer risk. Studies on dose reduction for CAS-CT are almost nonexistent. We validate the use of radiation dose reduced CAS-CT for clinically applied surface registration.

[Lethal atraumatic splenic rupture due to infectious mononucleosis]

The authors report on the sudden and unexpected death of a 20-year-old man from atraumatic rupture of the enlarged spleen due to infectious mononucleosis. The case exemplifies the forensic relevance of infectious mononucleosis, atraumatic splenic rupture and post-mortem serological tests.

Impact of daclizumab, low-dose cyclosporine, mycophenolate mofetil and steroids on renal function after kidney transplantation

Early and long-term use of cyclosporine A (CsA) leads to increased risks of renal toxicity. We hypothesized that administration of daclizumab in combination with mycophenolate mofetil (MMF) allows a relevant reduction in the dose of CsA.

Attacks on German public figures, 1968-2004: warning behaviors, potentially lethal and non-lethal acts, psychiatric status, and motivations

Fourteen non-terrorist attackers of public figures in Germany between 1968 and 2004 were intensively studied, with a particular focus on warning behaviors, attack behaviors, and the relationship between psychiatric diagnosis, symptoms, and motivations for the assault. A large proportion of the attackers were severely mentally ill, and most likely to be in the potentially lethal rather than the non-lethal group. A new typology of seven warning behaviors was applied to the data, and all were present, most frequently fixation and pathway warning behavior, and least frequently a direct threat. Psychiatric diagnosis could be closely linked to motivation when analyzed at the level of symptom and content of thought, often delusional. Most of the attacks were directed at political figures, and the majority occurred after 1995.

Nonlinear three-dimensional noise filter with low-dose CT angiography: effect on the detection of small high-contrast objects in a phantom model

To study the effect of a nonlinear noise filter on the detection of simulated endoleaks in a phantom with 80- and 100-kVp multidetector computed tomographic (CT) angiography.

Iterative Reconstruction Algorithm for Abdominal Multidetector CT at Different Tube Voltages: Assessment of Diagnostic Accuracy, Image Quality, and Radiation Dose in a Phantom Study

To assess the diagnostic accuracy, image quality, and radiation dose of an iterative reconstruction algorithm compared with a filtered back projection (FBP) algorithm for abdominal computed tomography (CT) at different tube voltages.

An education and training programme for radiological institutes: impact on the reduction of the CT radiation dose

To establish an education and training programme for the reduction of CT radiation doses and to assess this programme's efficacy.

State of the art low-dose CT angiography of the body

This review summarizes current evidence based on pertinent literature on low-dose computed tomography angiography (CTA) of the body. Various strategies for optimizing CTA protocols with the aim to lower the radiation dose while maintaining the diagnostic accuracy of the examination are summarized. To date, various publications have demonstrated that CTA of the body can be performed at a low radiation dose while providing high quality information. Nevertheless, a number of questions still need to be answered, including the optimal combination of tube voltage and tube current settings, as well as the appropriate protocol parameters in relation to the body physiognomy and the specific body region imaged.