Other articles by Benedikt Engels on PubMed

• Phase II Study of Preoperative Helical Tomotherapy for Rectal Cancer International Journal of Radiation Oncology, Biology, Physics. Mar, 2008  |   Pubmed ID: 17904302 To explore the efficacy and toxicity profile of helical tomotherapy in the preoperative treatment of patients with rectal cancer.
• Hypoxic Tumor Cell Radiosensitization: Role of the INOS/NO Pathway Bulletin Du Cancer. Mar, 2008  |   Pubmed ID: 18390408 Hypoxia is a common feature of the tumor microenvironment and a major cause of clinical radioresistance. During the last decades, several strategies to improve tumor oxygenation were developed such as breathing high oxygen content gas under hyperbaric conditions (3 atmosphere) and improving tumor perfusion by nicotinamide, in combination with carbogen breathing and accelerated radiotherapy to counteract tumor repopulation (ARCON). Other strategies to overcome hypoxia induced radioresistance are the use of hypoxic cell radiosensitizers, which mimic oxygen and enhance thereby radiation damage (e.g. the nitroimidazoles) and bioreductive drugs, which undergo intracellular reduction to form active cytotoxic species under low oxygen tension (e.g. mitomycin C and tirapazamine). A meta-analysis of all randomized trials in which some form of hypoxic modification was performed, showed an improved local control and survival, especially in cervix and head-and-neck cancer. Nevertheless, none of the discussed strategies are used in clinical routine because of feasibility and toxicity issues. We developed an alternative strategy that takes advantage of the microenvironment of solid tumors for tumor specific radiosensitization. The inducible isoform of nitric oxide synthase (iNOS) may be induced by bacterial LPS or its derivate lipid A, is expressed by a variety of solid tumors and generates NO at high rates inside tumor cells. This local production of NO results in efficient hypoxic tumor cell radiosensitization, at non-toxic extracellular concentrations of NO. In addition, iNOS is transcriptionally upregulated by hypoxia and proinflammatory cytokines such as interferon-gamma. Hence, we proposed the pro-inflammatory tumor infiltrate as a new target for radiosensitizing strategies and identified two mechanisms: First, tumor associated immune cells (macrophages, T/NK-cells) are a source of mediators that may induce the iNOS/NO pathway inside tumor cells. Second, tumor associated macrophages can produce high levels of NO that may radiosensitize bystander tumor cells. Our ongoing research is focused on combining immunostimulatory and radiosensitizing strategies.
• Metabolic Engineering of Taxadiene Biosynthesis in Yeast As a First Step Towards Taxol (Paclitaxel) Production Metabolic Engineering. May-Jul, 2008  |   Pubmed ID: 18485776 Metabolic engineering in microbes could be used to produce large amounts of valuable metabolites that are difficult to extract from their natural sources and too expensive or complex to produce by chemical synthesis. As a step towards the production of Taxol in the yeast Saccharomyces cerevisiae, we introduced heterologous genes encoding biosynthetic enzymes from the early part of the taxoid biosynthetic pathway, isoprenoid pathway, as well as a regulatory factor to inhibit competitive pathways, and studied their impact on taxadiene synthesis. Expression of Taxus chinensis taxadiene synthase alone did not increase taxadiene levels because of insufficient levels of the universal diterpenoid precursor geranylgeranyl diphosphate. Coexpression of T. chinensis taxadiene synthase and geranylgeranyl diphosphate synthase failed to increase levels, probably due to steroid-based negative feedback, so we also expressed a truncated version of 3-hydroxyl-3-methylglutaryl-CoA reductase (HMG-CoA reductase) isoenzyme 1 that is not subject to feedback inhibition and a mutant regulatory protein, UPC2-1, to allow steroid uptake under aerobic conditions, resulting in a 50% increase in taxadiene. Finally, we replaced the T. chinensis geranylgeranyl diphosphate synthase with its counterpart from Sulfolobus acidocaldarius, which does not compete with steroid synthesis, and codon optimized the T. chinensis taxadiene synthase gene to ensure high-level expression, resulting in a 40-fold increase in taxadiene to 8.7+/-0.85mg/l as well as significant amounts of geranylgeraniol (33.1+/-5.6mg/l), suggesting taxadiene levels could be increased even further. This is the first demonstration of such enhanced taxadiene levels in yeast and offers the prospect for Taxol production in recombinant microbes.
• Assessment of Intrafractional Movement and Internal Motion in Radiotherapy of Rectal Cancer Using Megavoltage Computed Tomography International Journal of Radiation Oncology, Biology, Physics. Jul, 2008  |   Pubmed ID: 18514785 The aim of this study was to provide estimates of setup and internal margins of patients treated for rectal carcinoma using helical tomotherapy and to assess possible margin adaptations. Using helical tomotherapy, highly conformal dose distributions can be created, and the integrated megavoltage computed tomography (MVCT) modality allows very precise daily patient positioning. In clinical protocols, however, margins originating from traditional setup procedures are still being applied. This work investigates whether this modality can aid in redefining treatment margins.
• Conformal Arc Radiotherapy for Prostate Cancer: Increased Biochemical Failure in Patients with Distended Rectum on the Planning Computed Tomogram Despite Image Guidance by Implanted Markers International Journal of Radiation Oncology, Biology, Physics. Jun, 2009  |   Pubmed ID: 19056185 To evaluate the effect of rectal distention on the planning computed tomogram on freedom from biochemical failure (FFBF) of prostate cancer patients treated with image-guided conformal arc radiotherapy.
• Assessment of Rectal Distention in Radiotherapy of Prostate Cancer Using Daily Megavoltage CT Image Guidance Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Mar, 2009  |   Pubmed ID: 19147247 Assessment of rectal distention in a group of patients who are not receiving daily rectum emptying procedures during a course of prostate cancer radiotherapy to investigate which patients could benefit from daily rectum emptying.
• Preoperative Helical Tomotherapy and Megavoltage Computed Tomography for Rectal Cancer: Impact on the Irradiated Volume of Small Bowel International Journal of Radiation Oncology, Biology, Physics. Aug, 2009  |   Pubmed ID: 19231097 Preoperative (chemo)radiotherapy is considered to be standard of care in locally advanced rectal cancer, but is associated with significant small-bowel toxicity. The aim of this study was to explore to what extent helical tomotherapy and daily megavolt (MV) CT imaging may reduce the irradiated volume of small bowel.
• Helical Tomotherapy with Simultaneous Integrated Boost for High-risk and Lymph Node-positive Prostate Cancer: Early Report on Acute and Late Toxicity Technology in Cancer Research & Treatment. Oct, 2009  |   Pubmed ID: 19754211 The use of whole pelvic radiotherapy (WPRT) for high-risk and lymph node-positive prostate cancer (PC) remains controversial. The purpose of this study was to evaluate the acute toxicity associated with helical tomotherapy in the treatment of high-risk and lymph node-positive prostate cancer. To do so, twenty-eight patients were treated to a dose of 54 Gy in daily fractions of 1.8 Gy to the pelvic lymph node area, while the prostate and the seminal vesicles received a simultaneous integrated boost (SIB) to a dose of 70.5 Gy. A SIB to a dose of 60 Gy was delivered to the involved lymph node region(s) in 8 patients with pelvic lymph node metastases. All patients received concurrent hormonal treatment. The incidence of grade 2 and 3 acute gastrointestinal (GI) toxicity was 7% and 0% respectively. Grade 2 and 3 acute genito-urinary (GU) side effects were observed in 14% and 4% of the patients respectively. No grade 4 side effects occurred. No increased toxicity was observed in the 8 lymph node-positive patients receiving a simultaneous pelvic nodal dose escalation. In conclusion, WPRT with a SIB to the prostate and seminal vesicles by helical tomotherapy resulted in a favourable toxicity profile. Pelvic nodal dose escalation in node-positive patients is feasible without increasing toxicity.
• Toxicity Report of a Phase 1/2 Dose-escalation Study in Patients with Inoperable, Locally Advanced Nonsmall Cell Lung Cancer with Helical Tomotherapy and Concurrent Chemotherapy Cancer. Jan, 2010  |   Pubmed ID: 19918925 The objective of the current study was to evaluate the feasibility and toxicity of radiation dose escalation with concurrent chemotherapy using helical tomotherapy (HT) in patients with inoperable, locally advanced, stage III nonsmall cell lung cancer (LANSCLC) (grading determined according to the American Joint Committee on Cancer 6th edition grading system).
• Toxicity and Outcome Results of a Class Solution with Moderately Hypofractionated Radiotherapy in Inoperable Stage III Non-small Cell Lung Cancer Using Helical Tomotherapy International Journal of Radiation Oncology, Biology, Physics. Aug, 2010  |   Pubmed ID: 20056350 To prospectively assess the feasibility, toxicity, and local control of a class solution protocol of moderately hypofractionated tomotherapy in Stage III, inoperable, locally advanced non-small-cell lung cancer patients.
• Volumetric Imaging by Megavoltage Computed Tomography for Assessment of Internal Organ Motion During Radiotherapy for Cervical Cancer International Journal of Radiation Oncology, Biology, Physics. Aug, 2010  |   Pubmed ID: 20378265 To assess the internal organ motion of the cervix and uterus by megavoltage computed tomography (MVCT) during intensity-modulated radiotherapy (IMRT).
• Bipolar Versus Monopolar Technique for Palliative Transurethral Prostate Resection Archives of Medical Science : AMS. Oct, 2010  |   Pubmed ID: 22419939 The aim was to evaluate the postoperative morbidity and outcome of palliative endoscopic resections for relief of infravesical obstruction in prostate cancer patients with hormone deprivation therapy, and to investigate the added value of bipolar technology over conventional monopolar resections.
• Prediction of Response to Neoadjuvant Radiotherapy in Patients with Locally Advanced Rectal Cancer by Means of Sequential 18FDG-PET International Journal of Radiation Oncology, Biology, Physics. May, 2011  |   Pubmed ID: 20605358 Morphologic imaging techniques perform poorly in assessing the response to preoperative radiotherapy (RT), mainly because of desmoplastic reactions. The aim of this study was to investigate the potential of sequential 18-fluoro-2-deoxy-d-glucose (18FDG-PET) in assessing the response of rectal cancer to neoadjuvant RT and to determine which parameters can be used as surrogate markers for histopathologic response.
• Daily Megavoltage Computed Tomography in Lung Cancer Radiotherapy: Correlation Between Volumetric Changes and Local Outcome International Journal of Radiation Oncology, Biology, Physics. Aug, 2011  |   Pubmed ID: 20638192 To assess the predictive or comparative value of volumetric changes, measured on daily megavoltage computed tomography during radiotherapy for lung cancer.
• Prospective, Risk-adapted Strategy of Stereotactic Body Radiotherapy for Early-stage Non-small-cell Lung Cancer: Results of a Phase II Trial International Journal of Radiation Oncology, Biology, Physics. Aug, 2011  |   Pubmed ID: 20708849 Validation of a prospective, risk-adapted strategy for early-stage non-small-cell lung cancer (NSCLC) patients treated with stereotactic body radiotherapy (SBRT).
• Cloning and Characterization of an Armillaria Gallica CDNA Encoding Protoilludene Synthase, Which Catalyzes the First Committed Step in the Synthesis of Antimicrobial Melleolides The Journal of Biological Chemistry. Mar, 2011  |   Pubmed ID: 21148562 Melleolides and related fungal sesquiterpenoid aryl esters are antimicrobial and cytotoxic natural products derived from cultures of the Homobasidiomycetes genus Armillaria. The initial step in the biosynthesis of all melleolides involves cyclization of the universal sesquiterpene precursor farnesyl diphosphate to produce protoilludene, a reaction catalyzed by protoilludene synthase. We achieved the partial purification of protoilludene synthase from a mycelial culture of Armillaria gallica and found that 6-protoilludene was its exclusive reaction product. Therefore, a further isomerization reaction is necessary to convert the 6-7 double bond into the 7-8 double bond found in melleolides. We expressed an A. gallica protoilludene synthase cDNA in Escherichia coli, and this also led to the exclusive production of 6-protoilludene. Sequence comparison of the isolated sesquiterpene synthase revealed a distant relationship to other fungal terpene synthases. The isolation of the genomic sequence identified the 6-protoilludene synthase to be present as a single copy gene in the genome of A. gallica, possessing an open reading frame interrupted with eight introns.
• Setup Accuracy of the Novalis ExacTrac 6DOF System for Frameless Radiosurgery International Journal of Radiation Oncology, Biology, Physics. Apr, 2012  |   Pubmed ID: 21477937 Stereotactic radiosurgery using frame-based positioning is a well-established technique for the treatment of benign and malignant lesions. By contrast, a new trend toward frameless systems using image-guided positioning techniques is gaining mainstream acceptance. This study was designed to measure the detection and positioning accuracy of the ExacTrac/Novalis Body (ET/NB) for rotations and to compare the accuracy of the frameless with the frame-based radiosurgery technique.
• Clinical Evaluation of a Robotic 6-degree of Freedom Treatment Couch for Frameless Radiosurgery International Journal of Radiation Oncology, Biology, Physics. May, 2012  |   Pubmed ID: 21945110 To evaluate the added value of 6-degree of freedom (DOF) patient positioning with a robotic couch compared with 4DOF positioning for intracranial lesions and to estimate the immobilization characteristics of the BrainLAB frameless mask (BrainLAB AG, Feldkirchen, Germany), more specifically, the setup errors and intrafraction motion.
• Phase II Study of Preoperative Helical Tomotherapy with a Simultaneous Integrated Boost for Rectal Cancer International Journal of Radiation Oncology, Biology, Physics. May, 2012  |   Pubmed ID: 22014952 The addition of concomitant chemotherapy to preoperative radiotherapy is considered the standard of care for patients with cT3-4 rectal cancer. The combined treatment modality increases the complete response rate and local control (LC), but has no impact on survival or the incidence of distant metastases. In addition, it is associated with considerable toxicity. As an alternative strategy, we explored prospectively, preoperative helical tomotherapy with a simultaneous integrated boost (SIB).
• Phase II Study of Helical Tomotherapy in the Multidisciplinary Treatment of Oligometastatic Colorectal Cancer Radiation Oncology (London, England). 2012  |   Pubmed ID: 22423615 Complete metastasectomy provides a real chance for long-term survival in patients with oligometastatic colorectal cancer (CRC). For inoperable patients, we evaluated in this study intensity-modulated and image-guided radiotherapy (IMRT-IGRT) by helical tomotherapy.
• Current Status of Intensified Neo-adjuvant Systemic Therapy in Locally Advanced Rectal Cancer Frontiers in Oncology. 2012  |   Pubmed ID: 22655273 The addition of 5-fluorouracil (5-FU) or its prodrug capecitabine to radiotherapy (RT) is a standard approach in the neo-adjuvant treatment of patients with rectal tumors extending beyond the muscularis propria (stage II) and/or with clinical evidence of regional lymph node metastases (stage III). According to European randomized trials, the combined treatment modality resulted in favorable local control rates as compared with radiotherapy (RT) alone, but no improvement was found regarding the occurrence of distant metastases or overall survival. In an effort to further enhance the response rates and to decrease the high incidence of distant metastases in locally advanced rectal cancer patients, the addition of other chemotherapeutical drugs and biologic agents as radiation sensitizers to neo-adjuvant 5-FU based chemoradiotherapy (CRT) has been recently investigated. The role of those agents is however questionable as first results from phase III data do not show improvement on pathologic complete remission and circumferential resection margin negative resection rates as compared to 5-FU based CRT, nevertheless an increased toxicity.
• Implementation of HybridArc Treatment Technique in Preoperative Radiotherapy of Rectal Cancer: Dose Patterns in Target Lesions and Organs at Risk As Compared to Helical Tomotherapy and RapidArc Radiation Oncology (London, England). 2012  |   Pubmed ID: 22849723 HybridArc is a novel treatment technique blending aperture-enhanced optimized arcs with discrete IMRT-elements, allowing selection of arcs with a set of static IMRT-beams. This study compared this new technique to helical Tomotherapy, and RapidArc, in preoperative radiotherapy of rectal cancer.
• Dosimetric Comparison of Different Treatment Modalities for Stereotactic Radiosurgery of Arteriovenous Malformations and Acoustic Neuromas Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Feb, 2013  |   Pubmed ID: 22884842 We investigated the influence of beam modulation on treatment planning by comparing four available stereotactic radiosurgery (SRS) modalities: Gamma-Knife-Perfexion, Novalis-Tx Dynamic-Conformal-Arc (DCA) and Dynamic-Multileaf-Collimation-Intensity-Modulated-radiotherapy (DMLC-IMRT), and Cyberknife.
• Exploration of Biosynthetic Access to the Shared Precursor of the Fusicoccane Diterpenoid Family Chemical Communications (Cambridge, England). May, 2013  |   Pubmed ID: 23295536 Herein preparative scale access to the shared precursor of the fusicoccane family of diterpenoids through biosynthesis in three different microbial hosts is reported. A method to purify the metabolite in high purity and on a preparative scale was explored.
• Initial Assessment of Tumor Tracking with a Gimbaled Linac System in Clinical Circumstances: a Patient Simulation Study Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Feb, 2013  |   Pubmed ID: 23398905 To have an initial assessment of the Vero Dynamic Tracking workflow in clinical circumstances and quantify the performance of the tracking system, a simulation study was set up on 5 lung and liver patients.
• Evaluation of the Clinical Usefulness for Using Verification Images During Frameless Radiosurgery Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Jul, 2013  |   Pubmed ID: 23714654 Our previous studies showed that intrafraction motion needs to be corrected for in frameless radiosurgery. This study was designed to evaluate if verification images can correct for mechanical inaccuracy and intrafraction motion. With proper immobilization and verification images on a regular basis during treatment, mechanical (table-) inaccuracies and intrafraction motion can be corrected for and the absence of PTV-margins warranted.
• A Randomized Hypofractionation Dose Escalation Trial for High Risk Prostate Cancer Patients: Interim Analysis of Acute Toxicity and Quality of Life in 124 Patients Radiation Oncology (London, England). 2013  |   Pubmed ID: 24007322 The α/β ratio for prostate cancer is postulated being in the range of 0.8 to 2.2 Gy, giving rise to the hypothesis that there may be a therapeutic advantage to hypofractionation. To do so, we carried out a randomized trial comparing hypofractionated and conventionally fractionated image-guided intensity modulated radiotherapy (IG-IMRT) in high-risk prostate cancer. Here, we report on acute toxicity and quality of life (QOL) for the first 124 randomized patients.
• A Complementary Dual-modality Verification for Tumor Tracking on a Gimbaled Linac System Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Dec, 2013  |   Pubmed ID: 24238982 For dynamic tracking of moving tumors, robust intra-fraction verification was required, to assure that tumor motion was properly managed during the course of radiotherapy. A dual-modality verification system, consisting of an on-board orthogonal kV and planar MV imaging device, was validated and applied retrospectively to patient data.
• Preoperative Intensity-modulated and Image-guided Radiotherapy with a Simultaneous Integrated Boost in Locally Advanced Rectal Cancer: Report on Late Toxicity and Outcome Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Jan, 2014  |   Pubmed ID: 24239243 The addition of chemotherapy to preoperative radiotherapy has been established as the standard of care for patients with cT3-4 rectal cancer. As an alternative strategy, we explored intensity-modulated and image-guided radiotherapy (IMRT-IGRT) with a simultaneous integrated boost (SIB) in a prospective phase II study. Here, we report outcome and late toxicity after a median follow-up of 54 months.
• Advances in Radiotherapy and Targeted Therapies for Rectal Cancer World Journal of Gastroenterology : WJG. Jan, 2014  |   Pubmed ID: 24415852 The last decade witnessed a significant progress in understanding the biology and immunology of colorectal cancer alongside with the technical innovations in radiotherapy. The stepwise implementation of intensity-modulated and image-guided radiation therapy by means of megavolt computed tomography and helical tomotherapy enabled us to anatomically sculpt dose delivery, reducing treatment related toxicity. In addition, the administration of a simultaneous integrated boost offers excellent local control rates. The novel challenge is the development of treatment strategies for medically inoperable patient and organ preserving approaches. However, distant control remains unsatisfactory and indicates an urgent need for biomarkers that predict the risk of tumor spread. The expected benefit of targeted therapies that exploit the tumor genome alone is so far hindered by high cost techniques and pharmaceuticals, hence hardly justifying rather modest improvements in patient outcomes. On the other hand, the immune landscape of colorectal cancer is now better clarified with regard to the immunosuppressive network that promotes immune escape. Both N2 neutrophils and myeloid-derived suppressor cells (MDSC) emerge as useful clinical biomarkers of poor prognosis, while the growing list of anti-MDSC agents shows promising ability to boost antitumor T-cell immunity in preclinical settings. Therefore, integration of genetic and immune biomarkers is the next logical step towards effective targeted therapies in the context of personalized cancer treatment.
• Impact of Planning Target Volume Margins and Rectal Distention on Biochemical Failure in Image-guided Radiotherapy of Prostate Cancer Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Apr, 2014  |   Pubmed ID: 24631146 A previous study in our department demonstrated the negative impact on freedom from biochemical failure (FFBF) of using too narrow planning target volume (PTV) margins during prostate image-guided radiotherapy (IGRT). Here, we investigated the impact of appropriate PTV margins and rectal distention on FFBF.
• Treating Patients with Real-time Tumor Tracking Using the Vero Gimbaled Linac System: Implementation and First Review Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Sep, 2014  |   Pubmed ID: 25049177 To report on the first clinical application of a real-time tumor tracking (RTTT) solution based on the Vero SBRT gimbaled linac system for treatment of moving tumors.
• Impact of Inadequate Respiratory Motion Management in SBRT for Oligometastatic Colorectal Cancer Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Nov, 2014  |   Pubmed ID: 25441611 Stereotactic body radiotherapy (SBRT) in oligometastatic colorectal cancer (CRC) resulted in a disappointing 1-year local control rate of 54% in our experience. We aimed to determine the root cause(s).
• Improving the Intra-fraction Update Efficiency of a Correlation Model Used for Internal Motion Estimation During Real-time Tumor Tracking for SBRT Patients: Fast Update or No Update? Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Sep, 2014  |   Pubmed ID: 25443498 For tumor tracking, a correlation model is used to estimate internal tumor position based on external surrogate motion. When patients experience an internal/external surrogate drift, an update of the correlation model is required to continue tumor tracking. In this study, the accuracy of the internal tumor position estimation for both the clinical available update at discrete points in time (rebuild) and an in-house developed non-clinical online update approach was investigated.
• Analysis of the Targeting Uncertainty of a Stereotactic Frameless Radiosurgery Technique for Arteriovenous Malformation Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. Dec, 2014  |   Pubmed ID: 25454170 In order to target arteriovenous malformations (AVM) in a frameless approach, registration of two-dimensional (2D) digital-subtracted-angiographs (DSA) with three-dimensional (3D) computed tomography (CT) is required. Targeting accuracy and delineation of a frameless 2D-DSA and 3D-CT image registration tool based on bony anatomy of the skull was evaluated. This frameless approach assures accurate target localization and can be used in a clinical setting.
• Quality Assurance of a 50-kV Radiotherapy Unit Using EBT3 GafChromic Film: A Feasibility Study Technology in Cancer Research & Treatment. Jan, 2015  |   Pubmed ID: 25575576 Radiochromic EBT3 film is gaining acceptance as a valuable dosimetry system for high-energy photon beams. The advantages of these films over other dosimetry systems are low spectral sensitivity and high spatial resolution. The aim of this study was to validate EBT3 film as a dosimeter for machine and treatment quality assurance (QA) of a 50-kV radiotherapy unit.
• Advances in Radiotherapy Delivery for Rectal Cancer: a European Perspective Expert Review of Gastroenterology & Hepatology. Apr, 2015  |   Pubmed ID: 25644307 Preoperative chemoradiotherapy and radiotherapy with an integrated boost offer excellent local control rates in patients with rectal cancer. The introduction of intensity-modulated radiotherapy and image-guided radiotherapy has drastically improved the tolerance of these treatments. The new challenge is developing organ-preserving strategies and curative treatments for medically inoperable patients. Contact radiotherapy seems efficient for small tumors. Tumor hypoxia limits the success of radiotherapy for locally advanced cancers. Modulation of the L-arginine/iNOS pathway and implementation of hypoxia imaging in radiotherapy planning may overcome this hurdle.
• A Multi-centre Analysis of Treatment Procedures and Error Components in Dynamic Tumour Tracking Radiotherapy Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology. May, 2015  |   Pubmed ID: 25998806 This study aimed to compare procedures for dynamic tumour tracking (DTT) using a gimbal-mounted linac between centres in Japan (KU-IBRI) and Belgium (UZB), to quantify tracking error (TE), and to estimate tumour-fiducial uncertainties and PTV margins.