Baseline concussion assessment performance by sex in military service academy rugby players: findings from the CARE Consortium.

BACKGROUND: Normative student-athlete concussion assessment data may not be appropriate for service academy members (SAMs), particularly rugby players, because of the uniqueness of their academic/military training environment. Having accurate baseline data for this population is important because of their high risk for concussion and frequent lack of assigned sports medicine professional. The primary purpose of this study was to characterise baseline performance on a concussion assessment battery, with secondary purpose to determine effect of sex and concussion history on these measures among SAM rugby players. METHODS: 601 rugby-playing SAMs (19.3±1.5 years, 37.9% female) completed baseline concussion assessments: the Sport Concussion Assessment Tool (SCAT) Symptom and Symptom Severity Checklist, Standard Assessment of Concussion (SAC) and a neuropsychological test (either ImPACT (Immediate Post Concussion Assessment and Cognitive Testing) or ANAM (Automated Neuropsychological Assessment Metrics)). Groups were compared using an independent samples t-test or Mann-Whitney U test. A 2 (sex) × 2 (concussion history) ANOVA was conducted to determine the effects of sex and concussion history on outcomes. RESULTS: Women reported greater SCAT total symptoms (3.3 vs 2.8, p<0.001, r=0.143) and symptom severities (5.7 vs 4.3, p<0.001, r=0.139), and performed worse on ImPACT Visual Memory (79.3 vs 82.6, p=0.002, r=0.144) than men. Women performed better than men on SAC (28.0 vs 27.7, p=0.03, r=0.088), ImPACT Reaction Time Composite (0.59 vs 0.61, p=0.04, r=0.092) and ANAM Code Substitution Delayed (64.3 vs 61.5, p=0.04, d=0.433). Individuals with a history of concussion reported lower ImPACT Symptom Severity (2.6 vs 4.2, p=0.02, r=0.110). There was no interaction between concussion history and sex on outcomes. CONCLUSIONS: These findings provide reference data for SAM rugby players on baseline assessments and to help in clinical decision-making when managing sports-related concussion in absence of baseline data.

Investigation of the mechanisms by which hot isostatic pressing improves the fatigue performance of powder bed fused Ti-6Al-4V.

Hot isostatic pressing (HIP) is often needed to obtain powder bed fused (PBF) Ti-6Al-4V parts with good fatigue performance. This manuscript attempts to clarify the mechanisms through which HIP treatment acts to improve high cycle fatigue performance. Several mechanisms are considered and examined against experimental data sets available in the literature. The results suggest that HIP may act most significantly by decreasing the fraction of the defect population that can initiate fatigue cracks, both by decreasing defect sizes below a threshold and by changing the microstructure that surrounds defects. Given the novelty of the latter conclusion, an electron backscatter diffraction microscopy study was performed for validation. The gained understanding provides initial guidance on the choice of optimum HIP soak parameters (Temperature-Pressure-Time) for the high cycle fatigue performance of PBF Ti-6Al-4V.

Brettanomyces bruxellensis SSU1 Haplotypes Confer Different Levels of Sulfite Tolerance When Expressed in a Saccharomyces cerevisiae SSU1 Null Mutant.

The addition of SO2 is practiced in the wine industry to mitigate the risk of microbial spoilage and to extend wine shelf-life. Generally, this strategy does not interfere with primary alcoholic fermentation, as wine strains of Saccharomyces cerevisiae exhibit significant SO2 tolerance, largely driven by the efflux pump Ssu1p. One of the key yeast species responsible for wine spoilage is Brettanomyces bruxellensis, which also exhibits strain-dependent SO2 tolerance, although this occurs via unknown mechanisms. To evaluate the factors responsible for the differential sulfite tolerance observed in B. bruxellensis strains, we employed a multifaceted approach to examine both expression and allelic differences in the BbSSU1 gene. Transcriptomic analysis following exposure to SO2 highlighted different inducible responses in two B. bruxellensis strains. It also revealed disproportionate transcription of one putative BbSSU1 haplotype in both genetic backgrounds. Here, we confirm the functionality of BbSSU1 by complementation of a null mutant in a S. cerevisiae wine strain. The expression of four distinct BbSSU1 haplotypes in the S. cerevisiae ΔSSU1 mutant revealed up to a 3-fold difference in conferred SO2 tolerance. Substitution of key amino acids distinguishing the encoded proteins was performed to evaluate their relative contribution to SO2 tolerance. Protein modeling of two haplotypes which differed in two amino acid residues suggested that these substitutions affect the binding of Ssu1p ligands near the channel opening. Taken together, preferential transcription of a BbSSU1 allele that encodes a more efficient Ssu1p transporter may represent one mechanism that contributes to differences in sulfite tolerances between B. bruxellensis strains.IMPORTANCEBrettanomyces bruxellensis is one of the most important wine spoilage microorganisms, with the use of sulfite being the major method to control spoilage. However, this species displays a wide intraspecies distribution in sulfite tolerance, with some strains capable of tolerating high concentrations of SO2, with relatively high concentrations of this antimicrobial needed for their control. Although SO2 tolerance has been studied in several organisms and particularly in S. cerevisiae, little is known about the mechanisms that confer SO2 tolerance in B. bruxellensis Here, we confirmed the functionality of the sulfite efflux pump encoded by BbSSU1 and determined the efficiencies of four different BbSSU1 haplotypes. Gene expression analysis showed greater expression of the haplotype conferring greater SO2 tolerance. Our results suggest that a combination of BbSSU1 haplotype efficiency, copy number, and haplotype expression levels likely contributes to the diverse SO2 tolerances observed for different B. bruxellensis strains.

Magnetic Resonance Image-Guided Radiotherapy (MRIgRT): A 4.5-Year Clinical Experience.

AIMS: Magnetic resonance image-guided radiotherapy (MRIgRT) has been clinically implemented since 2014. This technology offers improved soft-tissue visualisation, daily imaging, and intra-fraction real-time imaging without added radiation exposure, and the opportunity for adaptive radiotherapy (ART) to adjust for anatomical changes. Here we share the longest single-institution experience with MRIgRT, focusing on trends and changes in use over the past 4.5 years. MATERIALS AND METHODS: We analysed clinical information, including patient demographics, treatment dates, disease sites, dose/fractionation, and clinical trial enrolment for all patients treated at our institution using MRIgRT on a commercially available, integrated 0.35 T MRI, tri-cobalt-60 device from 2014 to 2018. For each patient, factors including disease site, clinical rationale for MRIgRT use, use of ART, and proportion of fractions adapted were summated and compared between individual years of use (2014-2018) to identify shifts in institutional practice patterns. RESULTS: Six hundred and forty-two patients were treated with 666 unique treatment courses using MRIgRT at our institution between 2014 and 2018. Breast cancer was the most common disease, with use of cine MRI gating being a particularly important indication, followed by abdominal sites, where the need for cine gating and use of ART drove MRIgRT use. One hundred and ninety patients were treated using ART in 1550 fractions, 67.6% (1050) of which were adapted. ART was primarily used in cancers of the abdomen. Over time, breast and gastrointestinal cancers became increasingly dominant for MRIgRT use, hypofractionated treatment courses became more popular, and gastrointestinal cancers became the principal focus of ART. DISCUSSION: MRIgRT is widely applicable within the field of radiation oncology and new clinical uses continue to emerge. At our institution to date, applications such as ART for gastrointestinal cancers and accelerated partial breast irradiation (APBI) for breast cancer have become dominant indications, although this is likely to continue to evolve.

Temporal variability of beryllium-7 fallout in southwest UK.

Cosmogenic beryllium-7 has been widely employed as a sediment tracing tool and continued development of its use as a soil erosion tracer requires knowledge of fallout temporal dynamics. Data regarding beryllium-7 fallout in the UK are scarce and here the authors provide a record of beryllium-7 fallout in southwest England spanning a two-year period. A monthly fallout record was developed for Plymouth, UK using regular rainfall sampling to determine beryllium-7 rainfall activity concentration (Bq L(-1)) and deposition flux (Bq m(-2)). Data showed a general tendency for higher activity during the spring/summer months and lower activity in the autumn/winter months. Comparison with data for other UK sites (Chilton and Aberporth) for the same period found significant differences in (7)Be activity in rainwater and lower variability in Plymouth than Chilton and Aberporth. Total deposition was largely controlled by rainfall in Plymouth although regression coefficients suggested greater importance of other atmospheric controls at the Chilton and Aberporth sites. Use of a deposition proportion to rainfall proportion ratio identified periods when deposition was influenced by varying (7)Be activity in rainfall. Broad ranges in ratios were found for Chilton and Aberporth and this has implications for sediment tracer studies requiring estimates of (7)Be deposition flux across months or seasons.

Tuning anatase and rutile phase ratios and nanoscale surface features by anodization processing onto titanium substrate surfaces.

Both the anatase (A) and rutile (R) phases of titanium oxide have shown enhanced antimicrobial and bioactivity levels but the specific A/R phase ratio needed for the best results is still unknown. In this study titanium samples were anodized to produce specific ratios of anatase and rutile phases within the oxide layers. Specific ratios produced included maximum A minimum R, minimum A maximum R, 50% A 50% R, minimum A minimum R, and a non-anodized titanium control group. Samples were characterized for phase distributions within the oxide layers, surface porosity, corrosion resistance, and bioactivity. Results indicated the targeted phase ratios were reproducibly achieved during the anodization process. Samples containing the highest levels of anatase showed the largest individual pore sizes, but a lower overall percent porosity value compared to samples containing higher rutile levels. EBSD examination of the anodized layer cross-sections provided valuable new spatial information on the distribution of anatase and rutile phases within the anodized layers. Highly porous oxide layers showed significantly higher corrosion rates compared to non-anodized titanium, but no significant differences were shown in the icorr values between samples containing primarily anatase phase, samples containing primarily rutile phase, and samples containing an approximate 50:50 mixture of the two phases. Minimum A minimum R samples showed substantially less porosity compared to the other anodization groups, a significantly lower oxide thickness, and comparable corrosion rates to non-anodized titanium. All samples within the study showed apatite production in simulated body fluid within the seven day test period indicating enhanced bioactivity.

Salvage reirradiation for locoregional failure after radiation therapy for prostate cancer: who, when, where and how?

Even in the current era of dose-escalated radiotherapy for prostate cancer, biochemical recurrence is not uncommon. Furthermore, biochemical failure is not specific to the site of recurrence. One of the major challenges in the management of prostate cancer patients with biochemical failure after radiotherapy is the early discrimination between those with locoregional recurrence only and those with metastatic disease. While the latter are generally considered incurable, patients with locoregional disease may benefit from emerging treatment options. Ultimately, the objective of salvage therapy is to control disease while ensuring minimal collateral damage, thereby optimizing both cancer and toxicity outcomes. Advances in functional imaging, including multiparametric prostate MRI, abdominopelvic lymphangio-MRI, sentinel node SPECT-CT and/or whole-body PET/CT have paved the way for salvage radiotherapy in patients with local recurrence, microscopic nodal disease limited to the pelvis or oligometastatic disease. These patients may be considered for salvage reirradiation using different techniques: prostate low-dose or high-dose rate brachytherapy, pelvic and/or lomboaortic image-guided radiotherapy with elective nodal irradiation, focal nodal or bone stereotactic body radiation therapy (SBRT). An individualized approach is recommended. The decision about which treatment, if any, to use will be based on the initial characteristics of the disease, relapse patterns and the natural history of the rising prostate specific antigen (PSA). Preliminary results suggest that more than 50% of patients who have undergone salvage reirradiation are biochemically relapse-free with very low rates of severe toxicity. Large prospective studies with a longer follow-up are needed to confirm the promising benefit/risk ratio observed with salvage brachytherapy and or salvage nodal radiotherapy and/or bone oligometastatic SBRT when compared with life-long palliative hormones.

Erectile dysfunction after radiotherapy for prostate cancer: a model assessing the conflicting literature on dose-volume effects.

Studies assessing the relationship between dose to the penile bulb (PB) and risk of ED in men treated for prostate cancer with external beam radiation therapy (EBRT) have been critically scored. A review of published literature examining dose received by the PB and clinical erectile function outcomes for patients receiving EBRT was performed. Of 146 retrieved articles, 8 evaluated EBRT-induced ED in relation to PB dose. Half of these articles showed a relationship between dose to PB and ED, and the other half did not. A reliability score (RS) was constructed to more uniformly evaluate strengths and weaknesses of these eight articles. Subsequently, they were scored by two independent reviewers. An average of both scores was calculated. A close consensus was found (identical RS for six of the eight studies; kappa statistic: P=0.97). The studies with highest RS consistently support a relationship between ED and PB doses, whereas those with low scores did not. The RS-based analysis supports the recommended dose-volume limits specified in the Quantitative Analysis of Normal Tissue Effects in the Clinic review, maintaining the mean dose to 95% of the PB<50 Gy, although the target organ at risk is not likely to be the PB.

Burden of Friedreich's Ataxia to the Patients and Healthcare Systems in the United States and Canada.

OBJECTIVE: The study intended to substantiate healthcare resource utilization, costs, and funding patterns of US and Canadian Friedreich's Ataxia (FRDA) populations, to assess compliance with treatment guidance and to identify areas where novel healthcare measures or improved access to existing care may improve patients' functional and social capabilities and reduce the financial impact on the healthcare systems. METHODS: Healthcare resource utilization and costs were collected in a cross-sectional study in the US (N = 197) and Canada (N = 43) and analyzed across severity of disease categories. Descriptive statistics, correlation analysis, and hypothesis testing were applied. RESULTS: In the US, healthcare costs of FRDA patients were higher than those of "adults with two and more chronic conditions." Significantly higher costs were incurred in advanced stages of the disease, with paid homecare being the main driver. This pattern was also observed in Canada. Compliance with the recommended annual neurological and cardiological follow-up was high, but was low for the recommended regular speech therapy. In the US public and private funding ratios were similar for the FRDA and the general populations. In Canada the private funding ratio for FRDA was higher than average. CONCLUSION: The variety of healthcare measures addressing the broad range of symptoms of FRDA, and the increasing use of paid home care as disease progresses made total US healthcare costs of FRDA exceed the costs of US adults with two and more chronic conditions. Therefore, measures delaying disease progression will allow patients to maintain their independence longer and may reduce costs to the healthcare system. Novel measures to address dysarthria and to ensure access to them should be further investigated. The higher than average private funding ratio in Canada was due to the relatively high cost of the pharmacological treatment of FRDA.

Nanopore formation on the surface oxide of commercially pure titanium grade 4 using a pulsed anodization method in sulfuric acid.

Titanium and its alloys form a thin amorphous protective surface oxide when exposed to an oxygen environment. The properties of this oxide layer are thought to be responsible for titanium and its alloys biocompatibility, chemical inertness, and corrosion resistance. Surface oxide crystallinity and pore size are regarded to be two of the more important properties in establishing successful osseointegration. Anodization is an electrochemical method of surface modification used for colorization marking and improved bioactivity on orthopedic and dental titanium implants. Research on titanium anodization using sulphuric acid has been reported in the literature as being primarily conducted in molarity levels 3 M and less using either galvanostatic or potentiostatic methods. A wide range of pore diameters ranging from a few nanometers up to 10 µm have been shown to form in sulfuric acid electrolytes using the potentiostatic and galvanostatic methods. Nano sized pores have been shown to be beneficial for bone cell attachment and proliferation. The purpose of the present research was to investigate oxide crystallinity and pore formation during titanium anodization using a pulsed DC waveform in a series of sulfuric acid electrolytes ranging from 0.5 to 12 M. Anodizing titanium in increasing sulfuric acid molarities showed a trend of increasing transformations of the amorphous natural forming oxide to the crystalline phases of anatase and rutile. The pulsed DC waveform was shown to produce pores with a size range from ≤0.01 to 1 µm(2). The pore size distributions produced may be beneficial for bone cell attachment and proliferation.

Irradiation of the prostate and pelvic lymph nodes with an adaptive algorithm.

PURPOSE: The simultaneous treatment of pelvic lymph nodes and the prostate in radiotherapy for prostate cancer is complicated by the independent motion of these two target volumes. In this work, the authors study a method to adapt intensity modulated radiation therapy (IMRT) treatment plans so as to compensate for this motion by adaptively morphing the multileaf collimator apertures and adjusting the segment weights. METHODS: The study used CT images, tumor volumes, and normal tissue contours from patients treated in our institution. An IMRT treatment plan was then created using direct aperture optimization to deliver 45 Gy to the pelvic lymph nodes and 50 Gy to the prostate and seminal vesicles. The prostate target volume was then shifted in either the anterior-posterior direction or in the superior-inferior direction. The treatment plan was adapted by adjusting the aperture shapes with or without re-optimizing the segment weighting. The dose to the target volumes was then determined for the adapted plan. RESULTS: Without compensation for prostate motion, 1 cm shifts of the prostate resulted in an average decrease of 14% in D-95%. If the isocenter is simply shifted to match the prostate motion, the prostate receives the correct dose but the pelvic lymph nodes are underdosed by 14% ± 6%. The use of adaptive morphing (with or without segment weight optimization) reduces the average change in D-95% to less than 5% for both the pelvic lymph nodes and the prostate. CONCLUSIONS: Adaptive morphing with and without segment weight optimization can be used to compensate for the independent motion of the prostate and lymph nodes when combined with daily imaging or other methods to track the prostate motion. This method allows the delivery of the correct dose to both the prostate and lymph nodes with only small changes to the dose delivered to the target volumes.

Optimisation of beryllium-7 gamma analysis following BCR sequential extraction.

The application of cosmogenic (7)Be as a sediment tracer at the catchment-scale requires an understanding of its geochemical associations in soil to underpin the assumption of irreversible adsorption. Sequential extractions offer a readily accessible means of determining the associations of (7)Be with operationally defined soil phases. However, the subdivision of the low activity concentrations of fallout (7)Be in soils into geochemical fractions can introduce high gamma counting uncertainties. Extending analysis time significantly is not always an option for batches of samples, owing to the on-going decay of (7)Be (t(1/2)=53.3 days). Here, three different methods of preparing and quantifying (7)Be extracted using the optimised BCR three-step scheme have been evaluated and compared with a focus on reducing analytical uncertainties. The optimal method involved carrying out the BCR extraction in triplicate, sub-sampling each set of triplicates for stable Be analysis before combining each set and coprecipitating the (7)Be with metal oxyhydroxides to produce a thin source for gamma analysis. This method was applied to BCR extractions of natural (7)Be in four agricultural soils. The approach gave good counting statistics from a 24 h analysis period (~10% (2σ) where extract activity >40% of total activity) and generated statistically useful sequential extraction profiles. Total recoveries of (7)Be fell between 84 and 112%. The stable Be data demonstrated that the extraction procedure had a high reproducibility (<1% RSD), thus gamma counting uncertainties dominated the overall uncertainty. In addition, extractions of soil equilibrated with stable Be at a concentration below the Cation Exchange Capacity (CEC) of the soil demonstrated that doubling the soil:solution ratio to enhance the mass of soil used in a sequential extraction scheme affects the apparent distribution of approximately 10% of the total Be. At high concentration, stable Be was found to be a poor proxy for (7)Be fallout in sequential extractions.

United States (US) multi-center study to assess the validity and reliability of the Spinal Cord Independence Measure (SCIM III).

STUDY DESIGN: Multi-center, prospective, cohort study. OBJECTIVES: To assess the validity and reliability of the Spinal Cord Independence Measure (SCIM III) in measuring functional ability in persons with spinal cord injury (SCI). SETTING: Inpatient rehabilitation hospitals in the United States (US). METHODS: Functional ability was measured with the SCIM III during the first week of admittance into inpatient acute rehabilitation and within one week of discharge from the same rehabilitation program. Motor and sensory neurologic impairment was measured with the American Spinal Injury Association Impairment Scale. The Functional Independence Measure (FIM), the default functional measure currently used in most US hospitals, was used as a comparison standard for the SCIM III. Statistical analyses were used to test the validity and reliability of the SCIM III. RESULTS: Total agreement between raters was above 70% on most SCIM III tasks and all κ-coefficients were statistically significant (P<0.001). The coefficients of Pearson correlation between the paired raters were above 0.81 and intraclass correlation coefficients were above 0.81. Cronbach's-α was above 0.7, with the exception of the respiration task. The coefficient of Pearson correlation between the FIM and SCIM III was 0.8 (P<0.001). For the respiration and sphincter management subscale, the SCIM III was more responsive to change, than the FIM (P<0.0001). CONCLUSION: Overall, the SCIM III is a reliable and valid measure of functional change in SCI. However, improved scoring instructions and a few modifications to the scoring categories may reduce variability between raters and enhance clinical utility.

Patient preferences for next generation neural prostheses to restore bladder function.

STUDY DESIGN: A survey administered to 66 individuals with spinal cord injury (SCI) implementing a choice-based conjoint (CBC) analysis. Six attributes with three levels each were defined and used to generate choice sets with treatment scenarios. Patients were asked to choose the scenario that they preferred most. OBJECTIVES: To determine the utility weights for treatment characteristics as well as the overall preference for the three types of neural prostheses (NP), that is Brindley, rhizotomy-free Brindley, and pudendal nerve stimulation. Earlier studies have revealed the importance of restoration of bladder function, but no studies have been performed to determine the importance of NP features. SETTING: Two academic affiliated medical systems' SCI outpatient and inpatient rehabilitation programs, Cleveland, OH. METHODS: CBC analysis followed by multinomial logit modeling. Individual part-worth utilities were estimated using hierarchical Bayes. RESULTS: Side effects had the greatest significant impact on subject choices, followed by the effectiveness on continence and voiding. NPs with rhizotomy-free sacral root stimulation were preferred (45% first choice) over pudendal afferent nerve stimulation (39% second choice) and sacral root stimulation with rhizotomy (53% third choice). Almost 20% did not want to have an NP at all times. CONCLUSION: CBC has shown to be a valuable tool to support design choices. The data showed that persons would prefer a bladder NP with minimally invasive electrodes, which would give them complete bladder function, with no side effects and that can be operated by pushing a button and they do not have to recharge themselves.

Health service research: the square peg in human subjects protection regulations.

Protection of human participants is a fundamental facet of biomedical research. We report the activities of a health service research study in which there were three institutional review boards (IRBs), three legal departments and one research administration department providing recommendations and mandating changes in the study methods. Complying with IRB requirements can be challenging, but can also adversely affect study outcomes. Multiple protocol changes mandated from multiple IRBs created a research method that was not reflective of how substance use screening would be performed in a clinical setting. There was direct conflict between the IRBs' perceptions of participants' protection with the researchers' need to use research methodology that assures the clinical relevancy of results.

The cardiovascular and pharmacokinetic profile of dofetilide in conscious telemetered beagle dogs and cynomolgus monkeys.

BACKGROUND AND PURPOSE: The effects of dofetilide were studied in monkeys and dogs. Pharmacokinetic data were generated together with the monitoring of cardiovascular changes in order to compare effects relative to human exposure. EXPERIMENTAL APPROACH: Beagle dogs and cynomolgus monkeys were telemetered to collect arterial blood pressure, heart rate and ECG for 6 h after selected oral doses of dofetilide. Pharmacokinetic parameters were determined for each dose. KEY RESULTS: Dogs: increases in the QT(c) interval reached 56 ms in dogs dosed with 0.3 mg kg(-1) of dofetilide. Premature ventricular contractions and right bundle branch block were evident at this dose, without changes in cardiovascular parameters. The mean C(max) values were 3.35 and 60.15 ng mL(-1) at doses of 0.03 and 0.3 mg kg(-1), respectively. Monkeys: increases in QT(c) intervals reached 40-50 ms after 0.03 mg kg(-1). T-wave changes were observed after 0.03 mg kg(-1) without changes in cardiovascular parameters. The mean C(max) values following oral doses of 0.01 and 0.03 mg kg(-1) were 0.919 ng mL(-1) and 1.85 ng mL(-1), respectively. CONCLUSIONS AND IMPLICATIONS: Despite dofetilide exposure comparable to that in humans, QT(c) responses in dogs were greater than those reported in humans. A comparable human dose used in the monkey achieved only half of the exposure but was associated with twofold greater increases in QT(c). Our data support the view that safety risk assessments of new drugs in animal models should ensure that the clinical therapeutic range of exposure is achieved and any untoward effects interpreted accordingly.

The use of megavoltage cone-beam CT to complement CT for target definition in pelvic radiotherapy in the presence of hip replacement.

In Europe and the USA combined, over half a million people had a hip joint replaced in 2005, contributing to the increasing number of radiotherapy patients with metallic hip prostheses. The treatment plan for external beam radiation therapy is based on the delineation of the anatomy in the planning CT scan. When implanted objects of high atomic number (Z) material are present, however, severe image artefacts are generated in conventional CT, strongly hindering the ability to delineate some organs. This is particularly the case for the planning of prostate patients with hip prostheses. This short communication presents the use of a new imaging modality, megavoltage cone-beam CT, to complement the regular CT for target definition of prostate cancer treatment of patients with hip replacements.

[Megavoltage cone-beam CT: Recent developments and clinical applications]. / Mégavoltage cone-beam CT: récents développements et applications cliniques pour la radiothérapie conformationnelle avec modulation d'intensité.

The Megavoltage cone-beam (MV CBCT) system consists of a new a-Si flat panel adapted for MV imaging and an integrated workflow application allowing the automatic acquisition of projection images, cone-beam CT image reconstruction, CT to CBCT image registration and couch position adjustment. This provides a 3D patient anatomy volume in the actual treatment position, relative to the treatment isocenter, moments before the dose delivery, that can be tightly aligned to the planning CT, allowing verification and correction of the patient position, detection of anatomical changes and dose calculation. In this paper, we present the main advantages and performance of this MV CBCT system and summarize the different clinical applications. Examples of the image-guided treatment process from the acquisition of the MV CBCT scan to the correction of the couch position and dose delivery will be presented for spinal and lung lesions and for head and neck, and prostate cancers.