Τρίτη, 13 Μαρτίου 2018

Influence of inhomogeneous radiosensitivity distributions and intrafractional organ movement on the tumour control probability of focused IMRT in prostate cancer

S01678140.gif

Publication date: Available online 13 March 2018
Source:Radiotherapy and Oncology
Author(s): Benedikt Thomann, Ilias Sachpazidis, Khodor Koubar, Constantinos Zamboglou, Panayiotis Mavroidis, Rolf Wiehle, Anca-Ligia Grosu, Dimos Baltas
PurposeTo evaluate the influence of radioresistance and intrafractional movement on the tumour control probability (TCP) in IMRT prostate treatments using simultaneous integrated boosts to PSMA-PET/CT-delineated GTVs.Materials and methods13 patients had PSMA-PET/CT prior to prostatectomy and histopathological examination. Two GTVs were available: GTV-PET and GTV-histo, which is the true cancer volume. Focused IMRT plans delivering 77 Gy in 35 fractions to the prostate and 95 Gy to PTV-PET were produced. For random portions of the true cancer volume, α and α/β were uniformly changed to represent different radiosensitivity reductions. TCP was calculated (linear quadratic model) for the true cancer volume with and without simulated intrafractional movement.ResultsIntrafractional movement increased the TCP by up to 10.2% in individual cases and 1.2% averaged over all cases for medium radiosensitivity levels. At lower levels of radiosensitivity, movement decreased the TCP. Radiosensitivity reductions of 10–20% led to TCP reductions of 1–24% and 10–68% for 1% and 5% affected cancer volume, respectively. There is no linear correlation but a sudden breakdown of TCPs within a small range of radiosensitivity levels.ConclusionTCP drops significantly within a narrow range of radiosensitivity levels. Intrafractional movement can increase TCP when the boost volume is surrounded by a sufficiently high dose plateau.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2tMM7xm

Cancer Trials Ireland (ICORG) 06-34: A multi-centre clinical trial using three-dimensional conformal radiation therapy to reduce the toxicity of palliative radiation for lung cancer

S01678140.gif

Publication date: Available online 13 March 2018
Source:Radiotherapy and Oncology
Author(s): Ronan L. McDermott, John G. Armstrong, Pierre Thirion, Mary Dunne, Marie Finn, Cormac Small, Mary Byrne, Carmel O'Shea, Lydia O'Sullivan, Aoife Shannon, Emma Kelly, Dayle J. Hacking
TitleCancer Trials Ireland (ICORG) 06-34: A multi-centre clinical trial using three-dimensional conformal radiation therapy to reduce the toxicity of palliative radiation for lung cancer. NCT01176487.Background & purposeTrials of radiation therapy for the palliation of intra-thoracic symptoms from locally advanced non-small cell lung cancer (NSCLC) have concentrated on optimising fractionation and dose schedules. In these trials, the rates of oesophagitis induced by this "palliative" therapy have been unacceptably high. In contrast, this non-randomised, single-arm trial was designed to assess if more technically advanced treatment techniques would result in equivalent symptom relief and reduce the side-effect of symptomatic oesophagitis.Materials & methodsThirty-five evaluable patients with symptomatic locally advanced or metastatic NSCLC were treated using a three-dimensional conformal technique (3-DCRT) and standardised dose regimens of 39 Gy in 13 fractions, 20 Gy in 5 fractions or 17 Gy in 2 fractions. Treatment plans sought to minimise oesophageal dose. Oesophagitis was recorded during treatment, at two weeks, one month and three months following radiation therapy and 3–6 monthly thereafter. Mean dose to the irradiated oesophagus was calculated for all treatment plans.ResultsFive patients (14%) had experienced grade 2 oesophagitis or dysphagia or both during treatment and 2 other patients had these side effects at the 2-week follow-up. At follow-up of one month after therapy, there was no grade two or higher oesophagitis or dysphagia reported. 22 patients were eligible for assessment of late toxicity. Five of these patients reported oesophagitis or dysphagia (one had grade 3 dysphagia, two had grade 2 oesophagitis, one of whom also had grade 2 dysphagia). Quality of Life (QoL) data at baseline and at 1-month follow up were available for 20 patients. At 1-month post radiation therapy, these patients had slightly less trouble taking a short walk, less shortness of breath, did not feel as weak, had better appetite and generally had a better overall quality of life than they did at baseline. They did report being slightly more tired.ConclusionsThis trial is the first of its kind showing that 3-DCRT provides patients with lower rates of oesophageal toxicity whilst yielding acceptable rates of symptom control. (Sponsored by Cancer Trials Ireland (ICORG) Study number 06-34, the Friends of St. Luke's and the St. Luke's Institute of Cancer Research.)



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2GtFt1O

A prospective cohort study of hepatic toxicity after stereotactic body radiation therapy for hepatocellular carcinoma

S01678140.gif

Publication date: Available online 13 March 2018
Source:Radiotherapy and Oncology
Author(s): Ting-Shi Su, Ren Luo, Ping Liang, Tao Cheng, Ying Zhou, Yong Huang
PurposeTo build and validate multivariate normal tissue complication probability (NTCP) models for radiation-induced hepatic toxicity (RIHT) after stereotactic body radiation therapy (SBRT).MethodsEighty-five patients with hepatocellular carcinoma (HCC) in a phase II clinical trial were enroled. A progression of at least 1 or 2 points in the Child–Pugh (CP) score post-SBRT was classified as RIHT (≥1 or ≥2). NTCP models for RIHT (≥1 or ≥2) were developed using logistic regression. Nomograms for each model were formulated. The cut-off point of each independent dosimetric risk factor was obtained using receiver-operating characteristic (ROC) analysis. We used an independent cohort (101 patients) for model validation.ResultsTwenty (23.5%) and 12 (14.2%) patients experienced RIHT (≥1) and RIHT (≥2), respectively. V15, VS10, and pretreatment CP (pre-CP) were the optimal predictors for RIHT (≥1 and ≥2) modelling. V15 ≤33.1% and VS10 ≥416.2 mL for RIHT (≥1), and V15 ≤21.5% and VS10 ≥621.8 mL for RIHT (≥2), were the cut-off points. Four NTCP models and their nomograms were generated. These models and nomograms showed good prediction performance (area under the curve (AUC), 0.83–0.89). Our NTCP model (RIHT ≥2) based on V15 plus pre-CP performed well (AUC = 0.78) in a validation cohort.ConclusionV15, VS10, and pre-CP are crucial predictors for RIHT (≥1 and ≥2). Our NTCP models and nomograms were conducive to obtain individual constraints for patients with HCC.Registration NumberChiCTR-IIC-16008233.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2tMM8Bq

Doing the right thing: Quality in radiotherapy, a European perspective

alertIcon.gif

Publication date: Available online 13 March 2018
Source:Radiotherapy and Oncology
Author(s): A Vaandering, N Jornet, P Scalliet, M Coffey, Y Lievens




from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2GqRaGy

The EPTN consensus-based atlas for CT- and MR-based contouring in neuro-oncology

grey_pxl.gif

Publication date: Available online 13 March 2018
Source:Radiotherapy and Oncology
Author(s): Daniëlle BP Eekers, Lieke in 't Ven, Erik Roelofs, Alida Postma, Claire Alapetite, Neil G. Burnet, Valentin Calugaru, Inge Compter, Ida E.M. Coremans, Morton Høyer, Maarten Lambrecht, Petra Witt Nyström, Alejandra Méndez Romero, Frank Paulsen, Ana Perpar, Dirk de Ruysscher, Laurette Renard, Beate Timmermann, Pavel Vitek, Damien C. Weber, Hiske L. van der Weide, Gillian A. Whitfield, Ruud Wiggenraad, Esther G.C. Troost
PurposeTo create a digital, online atlas for organs at risk (OAR) delineation in neuro-oncology based on high-quality computed tomography (CT) and magnetic resonance (MR) imaging.MethodsCT and 3 Tesla (3T) MR images (slice thickness 1 mm with intravenous contrast agent) were obtained from the same patient and subsequently fused. In addition, a 7T MR without intravenous contrast agent was obtained from a healthy volunteer. Based on discussion between experienced radiation oncologists, the clinically relevant organs at risk (OARs) to be included in the atlas for neuro-oncology were determined, excluding typical head and neck OARs previously published. The draft atlas was delineated by a senior radiation oncologist, 2 residents in radiation oncology, and a senior neuro-radiologist incorporating relevant available literature. The proposed atlas was then critically reviewed and discussed by European radiation oncologists until consensus was reached.ResultsThe online atlas includes one CT-scan at two different window settings and one MR scan (3T) showing the OARs in axial, coronal and sagittal view. This manuscript presents the three-dimensional descriptions of the fifteen consensus OARs for neuro-oncology. Among these is a new OAR relevant for neuro-cognition, the posterior cerebellum (illustrated on 7T MR images).ConclusionIn order to decrease inter- and intra-observer variability in delineating OARs relevant for neuro-oncology and thus derive consistent dosimetric data, we propose this atlas to be used in photon and particle therapy. The atlas is available online at www.cancerdata.org and will be updated whenever required.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2tJaP1J

Doing the right thing: Quality in radiotherapy, a European perspective

"You must never be fearful about what you are doing when it is right!"Marie Curie

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2tKGzn4

Cancer Trials Ireland (ICORG) 06-34: A multi-centre clinical trial using three-dimensional conformal radiation therapy to reduce the toxicity of palliative radiation for lung cancer

Cancer Trials Ireland (ICORG) 06-34: A multi-centre clinical trial using three-dimensional conformal radiation therapy to reduce the toxicity of palliative radiation for lung cancer. NCT01176487.

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2GpgxIt

Influence of inhomogeneous radiosensitivity distributions and intrafractional organ movement on the tumour control probability of focused IMRT in prostate cancer

To evaluate the influence of radioresistance and intrafractional movement on the tumour control probability (TCP) in IMRT prostate treatments using simultaneous integrated boosts to PSMA-PET/CT-delineated GTVs.

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2tJSTno

The EPTN consensus-based atlas for CT- and MR-based contouring in neuro-oncology

To create a digital, online atlas for organs at risk (OAR) delineation in neuro-oncology based on high-quality computed tomography (CT) and magnetic resonance (MR) imaging.

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2Gpgw7n

A prospective cohort study of hepatic toxicity after stereotactic body radiation therapy for hepatocellular carcinoma

To build and validate multivariate normal tissue complication probability (NTCP) models for radiation-induced hepatic toxicity (RIHT) after stereotactic body radiation therapy (SBRT).

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2tKGvDQ

Is the cervical vertebral maturation (CVM) method effective enough to replace the hand-wrist maturation (HWM) method in determining skeletal maturation?—A systematic review

Publication date: Available online 12 March 2018
Source:European Journal of Radiology
Author(s): Agnieszka Szemraj, Anna Wojtaszek-Słomińska, Bogna Racka-Pilszak
IntroductionChronological age provides only general information on the development of a child/adolescent. However, the biological age of the patient is more significant. One of the methods is the determination of the bone age based on the development of the hand and wrist bones. In 1972 a method for assessing cervical vertebral maturation on the cephalometric radiographs was introduced (CVM method). As a result, additional patient radiation was eliminated. Currently, this type of radiograph is routinely applied in orthodontic treatment.AIMThe aim of the study was to assess the usefulness of the CVM method and to verify the assumption, according to which the CVM method modified by Baccetti et al. may replace the method for the assessment of skeletal maturation based on a hand-wrist X-ray, which is known as the hand-wrist maturation (HWM) method.Material and methodsThe present study reviewed the literature between 2006 and 2016. In the first stage of selection 905 articles were obtained. Finally, 10 articles were enrolled for the review.ResultsAll of the studies presented a high level of correlation between the examined methods. In eight articles the researchers admitted that the CVM classification could replace the HWM method, known as the "gold standard". In two studies, the researchers suggested considering the CVM method an additional method despite its compatibility and usefulness. The lowest correlation coefficient was 0.616 and the highest 0.937.DiscussionThe assessment of the skeletal age with the CVM is done on a cephalometric radiograph, routinely used in orthodontic practice, which makes it easy to apply. The determination of features of only C2, C3 and C4 vertebrae is possible even if the patient wears an X-ray protective thyroid collar. Therefore, the radiation dose is minimized.ConclusionsThe CVM method shows a high level of correlation with the HWM method.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2tITUfs

Collaboration, campaigns and champions for appropriate imaging: feedback from the Zagreb workshop

Abstract

Leading radiologists and representatives from national radiation protection regulatory authorities and health ministries from 19 countries of the European region worked together with five experts at the workshop on justification and appropriate use of imaging in Zagreb, Croatia, from 26 to 28 October 2017 jointly organised by the IAEA and the European Society of Radiology. The workshop served as a forum to exchange information on challenges and solutions for improving justification and the appropriate use of diagnostic imaging. Common barriers to improving the use of imaging referral guidelines were discussed and the need for increased collaboration identified. Examples of good practices were presented, including use of Clinical Decision Support (CDS) systems to facilitate rapid and good justification decisions. The workshop identified some of the needs of European countries for achieving more appropriate imaging proposing wider use of collaboration, campaigns and champions.

Main messages

• Drivers for appropriate imaging in Europe are similar to those elsewhere globally.

• Implementing imaging referral guidelines is the main barrier to more appropriate imaging.

• Clinical Decision Support systems (CDS) facilitates good referral practice and justification decisions.

• Collaboration, campaigns and champions may improve awareness, appropriateness and audit.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2Iluhol

Editorial Board



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FE8SF7

Contents



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2God5y1

Automatic intraoperative estimation of blood flow direction during neurosurgical interventions

Abstract

Purpose

In neurosurgery, reliable information about blood vessel anatomy and flow direction is important to identify, characterize, and avoid damage to the vasculature. Due to ultrasound Doppler angle dependencies and the complexity of the vascular architecture, clinically valuable 3-D flow direction information is currently not available. In this paper, we aim to clinically validate and demonstrate the intraoperative use of a fully automatic method for estimation of 3-D blood flow direction from freehand 2-D Doppler ultrasound.

Methods

A 3-D vessel model is reconstructed from 2-D Doppler ultrasound and used to determine the vessel architecture. The blood flow direction is then estimated automatically using the model in combination with Doppler velocity data. To enable testing and validation during surgery, the method was implemented as part of the open-source navigation system CustusX (www.custusx.org).

Results

Ten patients were included prospectively. Data from four patients were processed postoperatively, and data from six patients were processed intraoperatively. In total, the blood flow direction was estimated for 48 different blood vessels with a success rate of 98%.

Conclusions

In this work, we have shown that the proposed method is suitable for fully automatic estimation of the blood flow direction in intracranial vessels during neurosurgical interventions. The method has the potential to make the understanding of the complex vascular anatomy and flow pattern more intuitive for the surgeon. The method is compatible with intraoperative use, and results can be presented within the limited time frame where they still are of clinical interest.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FzZVN1

Dynamic CTA in Native Kidneys Using a Multiphase CT Protocol—Potential of Significant Reduction of Contrast Medium

S10766332.gif

Publication date: Available online 12 March 2018
Source:Academic Radiology
Author(s): Margarita Braunagel, Florian Ortner, Ulf Schönermarck, Antje Habicht, Andreas Schindler, Manfred Stangl, Frederik F. Strobl, Maximilian Reiser, Dirk A. Clevert, Christoph Trumm, Andreas Helck
Rationale and ObjectiveThe objective of this study was to assess an optimized renal multiphase computed tomography angiography (MP-CTA) protocol regarding reduction of contrast volume.Materials and MethodsThirty patients underwent MP-CTA (12 phases, every 3.5 seconds, 80 kV/120 mAs) using 30 mL of contrast medium. The quality of MP-CTA was assessed quantitatively measuring vessel attenuation, image noise, and contrast-to-noise ratio. MP-CTA was evaluated qualitatively regarding depiction of vessels, cortex differentiation, and motion artifacts (grades 1–4, 1 = best). Mean effective radiation dose was registered. Results were compared to standard renal computed tomography angiography (CTA) (80 mL). Student t test was applied, if variables followed normal distribution. For other variables, nonparametric Mann-Whitney U test was used.ResultsAll acquisitions were successfully performed, and no patient had to be excluded from the study. MP-CTA enabled high attenuation (aorta: 503 ± 91 HU, renal arteries: 450 ± 73 HU/456 ± 72 HU) at adequate image noise (13.7 ± 1.5) and good contrast-to-noise ratio (34.2 ± 10.2). Good attenuation of renal veins was observed (286 ± 43 HU/282 ± 42 HU). Arterial enhancement was significantly higher compared to renal CTA (aorta: 396 ± 90 HU, renal arteries: 331 ± 74 HU/333 ± 80 HU; P < .001). MP-CTA protocol enabled good image quality of renal arteries (1.5 ± 0.6) and veins (1.7 ± 0.6). Cortex differentiation and motion artifacts were ranked 1.8 ± 0.8 and 1.6 ± 0.8. The mean effective radiation dose was 9 mSv (MP-CTA).ConclusionsCompared to standard renal CTA, the renal MP-CTA enabled the significant reduction of contrast volume and simultaneously provided a significantly higher arterial attenuation.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FPxfDm

Δημοφιλείς αναρτήσεις