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Sample records for assessing four-dimensional radiotherapy

  1. A novel four-dimensional radiotherapy method for lung cancer: imaging, treatment planning and delivery

    Science.gov (United States)

    Alasti, H.; Cho, Y. B.; Vandermeer, A. D.; Abbas, A.; Norrlinger, B.; Shubbar, S.; Bezjak, A.

    2006-06-01

    We present treatment planning methods based on four-dimensional computed tomography (4D-CT) to incorporate tumour motion using (1) a static field and (2) a dynamic field. Static 4D fields are determined to include the target in all breathing phases, whereas dynamic 4D fields are determined to follow the shape of the tumour assessed from 4D-CT images with a dynamic weighting factor. The weighting factor selection depends on the reliability of patient breathing and limitations of the delivery system. The static 4D method is compared with our standard protocol for gross tumour volume (GTV) coverage, mean lung dose and V20. It was found that the GTV delineated on helical CT without incorporating breathing motion does not adequately represent the target compared to the GTV delineated from 4D-CT. Dosimetric analysis indicates that the static 4D-CT based technique results in a reduction of the mean lung dose compared with the standard protocol. Measurements on a moving phantom and simulations indicated that 4D radiotherapy (4D-RT) synchronized with respiration-induced motion further reduces mean lung dose and V20, and may allow safe application of dose escalation and CRT/IMRT. The motions of the chest cavity, tumour and thoracic structures of 24 lung cancer patients are also analysed.

  2. Impact on four dimensional dose accumulation using deformable image registration in liver stereotactic body radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Seong Hee; Kim, Tae Ho; Kim, Dong Su; Seong, Cheon Keum; Cho, Min Seok; Kim, Kyeong Hyeon; Suh, Tae Suk [Dept of. Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Park, So Hyun [Dept. of Radiation Oncology, Uijeongbu ST Mary' s Hospital, the Catholic University of Korea, Uijeongbu (Korea, Republic of); Kim, Si Yong [Dept. of Radiation Oncology, Virginia Commonwealth University, Richmond (United States)

    2014-11-15

    This study aims to evaluate the dosimetric effect of four-dimensional dose accumulation (4D dose) compared to 3D dose in liver stereotactic body radiotherapy (SBRT). Currently, SBRTT has been widely used to deliver highly conformal dose to target while sparing normal tissue. So, SBRT need accurate target delineation, dose calculation and motion management techniques such as breath-hold or abdominal compressor. In spite of the benefits about these techniques, there are still deformation and movement which could lead to reduce the probability for tumor control, imprecise prediction of normal tissue complication. 4D dose accumulation which can consider dosimetric effect of respiratory motion has a possibility to predict the more accurate delivered dose to target and normal organs and improve treatment accuracy.

  3. Four-dimensional dose evaluation using deformable image registration in radiotherapy for liver cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hoon Jung, Sang; Min Yoon, Sang; Ho Park, Sung; Cho, Byungchul; Won Park, Jae; Jung, Jinhong; Park, Jin-hong; Hoon Kim, Jong; Do Ahn, Seung [Departments of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 138-736 (Korea, Republic of)

    2013-01-15

    Purpose: In order to evaluate the dosimetric impact of respiratory motion on the dose delivered to the target volume and critical organs during free-breathing radiotherapy, a four-dimensional dose was evaluated using deformable image registration (DIR). Methods: Four-dimensional computed tomography (4DCT) images were acquired for 11 patients who were treated for liver cancer. Internal target volume-based treatment planning and dose calculation (3D dose) were performed using the end-exhalation phase images. The four-dimensional dose (4D dose) was calculated based on DIR of all phase images from 4DCT to the planned image. Dosimetric parameters from the 4D dose, were calculated and compared with those from the 3D dose. Results: There was no significant change of the dosimetric parameters for gross tumor volume (p > 0.05). The increase D{sub mean} and generalized equivalent uniform dose (gEUD) for liver were by 3.1%{+-} 3.3% (p= 0.003) and 2.8%{+-} 3.3% (p= 0.008), respectively, and for duodenum, they were decreased by 15.7%{+-} 11.2% (p= 0.003) and 15.1%{+-} 11.0% (p= 0.003), respectively. The D{sub max} and gEUD for stomach was decreased by 5.3%{+-} 5.8% (p= 0.003) and 9.7%{+-} 8.7% (p= 0.003), respectively. The D{sub max} and gEUD for right kidney was decreased by 11.2%{+-} 16.2% (p= 0.003) and 14.9%{+-} 16.8% (p= 0.005), respectively. For left kidney, D{sub max} and gEUD were decreased by 11.4%{+-} 11.0% (p= 0.003) and 12.8%{+-} 12.1% (p= 0.005), respectively. The NTCP values for duodenum and stomach were decreased by 8.4%{+-} 5.8% (p= 0.003) and 17.2%{+-} 13.7% (p= 0.003), respectively. Conclusions: The four-dimensional dose with a more realistic dose calculation accounting for respiratory motion revealed no significant difference in target coverage and potentially significant change in the physical and biological dosimetric parameters in normal organs during free-breathing treatment.

  4. A novel four-dimensional radiotherapy planning strategy from a tumor-tracking beam's eye view

    Science.gov (United States)

    Li, Guang; Cohen, Patrice; Xie, Huchen; Low, Daniel; Li, Diana; Rimner, Andreas

    2012-11-01

    To investigate the feasibility of four-dimensional radiotherapy (4DRT) planning from a tumor-tracking beam's eye view (ttBEV) with reliable gross tumor volume (GTV) delineation, realistic normal tissue representation, high planning accuracy and low clinical workload, we propose and validate a novel 4D conformal planning strategy based on a synthesized 3.5D computed tomographic (3.5DCT) image with a motion-compensated tumor. To recreate patient anatomy from a ttBEV in the moving tumor coordinate system for 4DRT planning (or 4D planning), the centers of delineated GTVs in all phase CT images of 4DCT were aligned, and then the aligned CTs were averaged to produce a new 3.5DCT image. This GTV-motion-compensated CT contains a motionless target (with motion artifacts minimized) and motion-blurred normal tissues (with a realistic temporal density average). Semi-automatic threshold-based segmentation of the tumor, lung and body was applied, while manual delineation was used for other organs at risk (OARs). To validate this 3.5DCT-based 4D planning strategy, five patients with peripheral lung lesions of small size (V50) of prescribed dose of these 4D plans. The volume of the delineated GTV from different phase CTs varied dramatically from 24% to 112% among the five patients, whereas the GTV from 3.5DCT deviated from the averaged GTV in 4DCT by only -6%±6%. For planning tumor volume (PTV) coverage, the difference between the DVH3.5D and iDVH4D was negligible (<1% area), whereas the DVH3.5D and DVH4D were quite different, due to DIR uncertainty (˜2 mm), which propagates to PTV dose coverage with a pronounced uncertainty for small tumors (0.3-4.0 cm3) in stereotactic plans with sharp dose falloff around PTV. For OARs, such as the lung, heart, cord and esophagus, the three DVH curves (DVH3.5D, DVH4D and iDVH4D) were found to be almost identical for the same patients, especially in high-dose regions. For the tumor-containing lung, the relative difference of the areas

  5. An analysis of respiratory induced kidney motion on four-dimensional computed tomography and its implications for stereotactic kidney radiotherapy

    International Nuclear Information System (INIS)

    Stereotactic ablative body radiotherapy (SABR) is an emerging treatment modality for primary renal cell carcinoma. To account for respiratory-induced target motion, an internal target volume (ITV) concept is often used in treatment planning of SABR. The purpose of this study is to assess patterns of kidney motion and investigate potential surrogates of kidney displacement with the view of ITV verification during treatment. Datasets from 71 consecutive patients with free breathing four-dimensional computed tomography (4DCT) planning scans were included in this study. The displacement of the left and right hemi-diaphragm, liver dome and abdominal wall were measured and tested for correlation with the displacement of the both kidneys and patient breathing frequency. Nine patients were excluded due to severe banding artifact. Of 62 evaluable patients, the median age was 68 years, with 41 male patients and 21 female patients. The mean (range) of the maximum, minimum and average breathing frequency throughout the 4DCTs were 20.1 (11–38), 15.1 (9–24) and 17.3 (9–27.5) breaths per minute, respectively. The mean (interquartile range) displacement of the left and right kidneys was 0.74 cm (0.45-0.98 cm) and 0.75 cm (0.49-0.97) respectively. The amplitude of liver-dome motion was correlated with right kidney displacement (r=0.52, p<0.001), but not with left kidney displacement (p=0.796). There was a statistically significant correlation between the magnitude of right kidney displacement and that of abdominal displacement (r=0.36, p=0.004), but not the left kidney (r=0.24, p=0.056). Hemi-diaphragm displacements were correlated with kidney displacements respectively, with a weaker correlation for the left kidney/left diaphragm (r=0.45, [95% CI 0.22 to 0.63], p=<0.001) than for the right kidney/right diaphragm (r=0.57, [95% CI 0.37 to 0.72], p=<0.001). For the majority of patients, maximal left and right kidney displacement is subcentimeter in magnitude. The magnitude of

  6. A study on the influence of breathing phases in intensity-modulated radiotherapy of lung tumours using four-dimensional CT

    OpenAIRE

    Wu, W. C.; Chan, C. L.; Wong, Y W; Cuijpers, J P

    2010-01-01

    During gated intensity-modulated radiotherapy (IMRT) treatment for patients with inoperable non-small cell lung cancer (NSCLC), the end-expiration (EE) phase of respiratory is more stable, whereas end-inspiration (EI) spares more normal lung tissue. This study compared the relative plan quality based on dosimetric and biological indices of the planning target volume (PTV) and organs at risk (OARs) between EI and EE in gated IMRT. 16 Stage I NSCLC patients, who were scanned by four-dimensional...

  7. Four-dimensional (4D) Motion Detection to Correct Respiratory Effects in Treatment Response Assessment Using Molecular Imaging Biomarkers

    Science.gov (United States)

    Schreibmann, Eduard; Crocker, Ian; Schuster, David M.; Curran, Walter J.; Fox, Tim

    2014-01-01

    Observing early metabolic changes in positron emission tomography (PET) is an essential tool to assess treatment efficiency in radiotherapy. However, for thoracic regions, the use of three-dimensional (3D) PET imaging is unfeasible because the radiotracer activity is smeared by the respiratory motion and averaged during the imaging acquisition process. This motion-induced degradation is similar in magnitude with the treatment-induced changes, and the two occurrences become indiscernible. We present a customized temporal-spatial deformable registration method for quantifying respiratory motion in a four-dimensional (4D) PET dataset. Once the motion is quantified, a motion-corrected (MC) dataset is created by tracking voxels to eliminate breathing-induced changes in the 4D imaging scan. The 4D voxel-tracking data is then summed to yield a 3D MC-PET scan containing only treatment-induced changes. This proof of concept is exemplified on both phantom and clinical data, where the proposed algorithm tracked the trajectories of individual points through the 4D datasets reducing motion to less than 4 mm in all phases. This correction approach using deformable registration can discern motion blurring from treatment-induced changes in treatment response assessment using PET imaging. PMID:24000982

  8. Novel Assessment of Renal Motion in Children as Measured via Four-Dimensional Computed Tomography

    International Nuclear Information System (INIS)

    Objectives: Abdominal intensity-modulated radiation therapy and proton therapy require quantification of target and organ motion to optimize localization and treatment. Although addressed in adults, there is no available literature on this issue in pediatric patients. We assessed physiologic renal motion in pediatric patients. Methods and Materials: Twenty free-breathing pediatric patients at a median age of 8 years (range, 2–18 years) with intra-abdominal tumors underwent computed tomography simulation and four-dimensional computed tomography acquisition (slice thickness, 3 mm). Kidneys and diaphragms were contoured during eight phases of respiration to estimate center-of-mass motion. We quantified center of kidney mass mobility vectors in three dimensions: anteroposterior (AP), mediolateral (ML), and superoinferior (SI). Results: Kidney motion decreases linearly with decreasing age and height. The 95% confidence interval for the averaged minima and maxima of renal motion in children younger than 9 years was 5–9 mm in the ML direction, 4–11 mm in the AP direction, and 12–25 mm in the SI dimension for both kidneys. In children older than 9 years, the same confidence interval reveals a widening range of motion that was 5–16 mm in the ML direction, 6–17 mm in the AP direction, and 21–52 mm in the SI direction. Although not statistically significant, renal motion correlated with diaphragm motion in older patients. The correlation between diaphragm motion and body mass index was borderline (r = 0.52, p = 0.0816) in younger patients. Conclusions: Renal motion is age and height dependent. Measuring diaphragmatic motion alone does not reliably quantify pediatric renal motion. Renal motion in young children ranges from 5 to 25 mm in orientation-specific directions. The vectors of motion range from 5 to 52 mm in older children. These preliminary data represent novel analyses of pediatric intra-abdominal organ motion.

  9. SU-E-J-110: Dosimetric Analysis of Respiratory Motion Based On Four-Dimensional Dose Accumulation in Liver Stereotactic Body Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S; Kim, D; Kim, T; Kim, K; Cho, M; Shin, D; Suh, T [The Catholic University of Korea College of Medicine, Seoul (Korea, Republic of); Kim, S [Virginia Commonwealth University, Richmond, VA (United States); Park, S [Uijeongbu St.Mary’s Hospital, GyeongGi-Do (Korea, Republic of)

    2015-06-15

    Purpose: Respiratory motion in thoracic and abdominal region could lead to significant underdosing of target and increased dose to healthy tissues. The aim of this study is to evaluate the dosimetric effect of respiratory motion in conventional 3D dose by comparing 4D deformable dose in liver stereotactic body radiotherapy (SBRT). Methods: Five patients who had previously treated liver SBRT were included in this study. Four-dimensional computed tomography (4DCT) images with 10 phases for all patients were acquired on multi-slice CT scanner (Siemens, Somatom definition). Conventional 3D planning was performed using the average intensity projection (AIP) images. 4D dose accumulation was calculated by summation of dose distribution for all phase images of 4DCT using deformable image registration (DIR) . The target volume and normal organs dose were evaluated with the 4D dose and compared with those from 3D dose. And also, Index of achievement (IOA) which assesses the consistency between planned dose and prescription dose was used to compare target dose distribution between 3D and 4D dose. Results: Although the 3D dose calculation considered the moving target coverage, significant differences of various dosimetric parameters between 4D and 3D dose were observed in normal organs and PTV. The conventional 3D dose overestimated dose to PTV, however, there was no significant difference for GTV. The average difference of IOA which become ‘1’ in an ideal case was 3.2% in PTV. The average difference of liver and duodenum was 5% and 16% respectively. Conclusion: 4D dose accumulation which can provide dosimetric effect of respiratory motion has a possibility to predict the more accurate delivered dose to target and normal organs and improve treatment accuracy. This work was supported by the Radiation Technology R&D program (No. 2013M2A2A7043498) and the Mid-career Researcher Program (2014R1A2A1A10050270) through the National Research Foundation of Korea funded by the

  10. The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

    International Nuclear Information System (INIS)

    Purpose: Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment. Methods: A Perspex thorax phantom was used to simulate a patient. Three wooden “lung” inserts with embedded Perspex “lesions” were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours. Results: When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to

  11. Evaluation of Four-Dimensional Computed Tomography-Based Intensity-Modulated and Respiratory-Gated Radiotherapy Techniques for Pancreatic Carcinoma

    International Nuclear Information System (INIS)

    Purpose: To compare conformal radiotherapy (CRT), intensity-modulated radiotherapy (IMRT), and respiration-gated radiotherapy (RGRT) planning techniques for pancreatic cancer. All target volumes were determined using four-dimensional computed tomography scans (4D CT). Methods and Materials: The pancreatic tumor and enlarged regional lymph nodes were contoured on all 10 phases of a planning 4D CT scan for 10 patients, and the planning target volumes (PTVallphases) were generated. Three consecutive respiratory phases for RGRT delivery in both inspiration and expiration were identified, and the corresponding PTVs (PTVinspiration and PTVexpiration) and organ at risk volumes created. Treatment plans using CRT and IMRT, with and without RGRT, were created for each PTV. Results: Compared with the CRT plans, IMRT significantly reduced the mean volume of right kidney exposed to 20 Gy from 27.7% ± 17.7% to 16.0% ± 18.2% (standard deviation) (p < 0.01), but this was not achieved for the left kidney (11.1% ± 14.2% to 5.7% ± 6.5%; p = 0.1). The IMRT plans also reduced the mean gastric, hepatic, and small bowel doses (p < 0.01). No additional reductions in the dose to the kidneys or other organs at risk were seen when RGRT plans were combined with either CRT or IMRT, and the findings for RGRT in end-expiration and end-inspiration were similar. Conclusion: 4D CT-based IMRT plans for pancreatic tumors significantly reduced the radiation doses to the right kidney, liver, stomach, and small bowel compared with CRT plans. The additional dosimetric benefits from RGRT appear limited in this setting

  12. Development of an ultrasmall C-band linear accelerator guide for a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head.

    Science.gov (United States)

    Kamino, Yuichiro; Miura, Sadao; Kokubo, Masaki; Yamashita, Ichiro; Hirai, Etsuro; Hiraoka, Masahiro; Ishikawa, Junzo

    2007-05-01

    We are developing a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head. It is capable of pursuing irradiation and delivering irradiation precisely with the help of an agile moving x-ray head on the gimbals. Requirements for the accelerator guide were established, system design was developed, and detailed design was conducted. An accelerator guide was manufactured and basic beam performance and leakage radiation from the accelerator guide were evaluated at a low pulse repetition rate. The accelerator guide including the electron gun is 38 cm long and weighs about 10 kg. The length of the accelerating structure is 24.4 cm. The accelerating structure is a standing wave type and is composed of the axial-coupled injector section and the side-coupled acceleration cavity section. The injector section is composed of one prebuncher cavity, one buncher cavity, one side-coupled half cavity, and two axial coupling cavities. The acceleration cavity section is composed of eight side-coupled nose reentrant cavities and eight coupling cavities. The electron gun is a diode-type gun with a cerium hexaboride (CeB6) direct heating cathode. The accelerator guide can be operated without any magnetic focusing device. Output beam current was 75 mA with a transmission efficiency of 58%, and the average energy was 5.24 MeV. Beam energy was distributed from 4.95 to 5.6 MeV. The beam profile, measured 88 mm from the beam output hole on the axis of the accelerator guide, was 0.7 mm X 0.9 mm full width at half maximum (FWHM) width. The beam loading line was 5.925 (MeV)-Ib (mA) X 0.00808 (MeV/mA), where Ib is output beam current. The maximum radiation leakage of the accelerator guide at 100 cm from the axis of the accelerator guide was calculated as 0.33 cGy/min at the rated x-ray output of 500 cGy/min from the measured value. This leakage requires no radiation shielding for the accelerator guide itself per IEC 60601-2-1. PMID:17555261

  13. Development of an ultrasmall C-band linear accelerator guide for a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head.

    Science.gov (United States)

    Kamino, Yuichiro; Miura, Sadao; Kokubo, Masaki; Yamashita, Ichiro; Hirai, Etsuro; Hiraoka, Masahiro; Ishikawa, Junzo

    2007-05-01

    We are developing a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head. It is capable of pursuing irradiation and delivering irradiation precisely with the help of an agile moving x-ray head on the gimbals. Requirements for the accelerator guide were established, system design was developed, and detailed design was conducted. An accelerator guide was manufactured and basic beam performance and leakage radiation from the accelerator guide were evaluated at a low pulse repetition rate. The accelerator guide including the electron gun is 38 cm long and weighs about 10 kg. The length of the accelerating structure is 24.4 cm. The accelerating structure is a standing wave type and is composed of the axial-coupled injector section and the side-coupled acceleration cavity section. The injector section is composed of one prebuncher cavity, one buncher cavity, one side-coupled half cavity, and two axial coupling cavities. The acceleration cavity section is composed of eight side-coupled nose reentrant cavities and eight coupling cavities. The electron gun is a diode-type gun with a cerium hexaboride (CeB6) direct heating cathode. The accelerator guide can be operated without any magnetic focusing device. Output beam current was 75 mA with a transmission efficiency of 58%, and the average energy was 5.24 MeV. Beam energy was distributed from 4.95 to 5.6 MeV. The beam profile, measured 88 mm from the beam output hole on the axis of the accelerator guide, was 0.7 mm X 0.9 mm full width at half maximum (FWHM) width. The beam loading line was 5.925 (MeV)-Ib (mA) X 0.00808 (MeV/mA), where Ib is output beam current. The maximum radiation leakage of the accelerator guide at 100 cm from the axis of the accelerator guide was calculated as 0.33 cGy/min at the rated x-ray output of 500 cGy/min from the measured value. This leakage requires no radiation shielding for the accelerator guide itself per IEC 60601-2-1.

  14. The Four Dimensional Symptoms Questionnaire (4DSQ): A validation study of a multidimensional self-report questionnaire to assess distress, depression, anxiety and somatization

    OpenAIRE

    van Balkom Anton JLM; van Boeijen Christine A; Hermens Marleen LM; Penninx Brenda WJH; de Vet Henrica CW; Adèr Herman J; van Marwijk Harm WJ; Terluin Berend; van der Klink Jac JL; Stalman Wim AB

    2006-01-01

    Abstract Background The Four-Dimensional Symptom Questionnaire (4DSQ) is a self-report questionnaire that has been developed in primary care to distinguish non-specific general distress from depression, anxiety and somatization. The purpose of this paper is to evaluate its criterion and construct validity. Methods Data from 10 different primary care studies have been used. Criterion validity was assessed by comparing the 4DSQ scores with clinical diagnoses, the GPs' diagnosis of any psychosoc...

  15. Leadership as social identity management: Introducing the Identity Leadership Inventory (ILI) to assess and validate a four-dimensional model

    OpenAIRE

    Steffens, Niklas K; Haslam, S Alexander; Reicher, Stephen D.; Platow, Michael J; Fransen, Katrien; Yang, Jie; Ryan, Michelle K.; Jetten, Jolanda; Peters, Kim O.; Boen, Filip

    2014-01-01

    Although nearly two decades of research has provided support for the social identity approach to leadership, most previous work has focused on leaders’ identity prototypicality while neglecting the assessment of other equally important dimensions of social identity management. However, recent theoretical developments have argued that in order to mobilize and direct followers’ energies, leaders need not only to ‘be one of us’ (identity prototypicality), but also to ‘do it for us’ (identity adv...

  16. Four-Dimensional Computed Tomography Based Respiratory-Gated Radiotherapy with Respiratory Guidance System: Analysis of Respiratory Signals and Dosimetric Comparison

    OpenAIRE

    2014-01-01

    Purpose. To investigate the effectiveness of respiratory guidance system in 4-dimensional computed tomography (4DCT) based respiratory-gated radiation therapy (RGRT) by comparing respiratory signals and dosimetric analysis of treatment plans. Methods. The respiratory amplitude and period of the free, the audio device-guided, and the complex system-guided breathing were evaluated in eleven patients with lung or liver cancers. The dosimetric parameters were assessed by comparing free breathing ...

  17. Four-Dimensional Computed Tomography Based Respiratory-Gated Radiotherapy with Respiratory Guidance System: Analysis of Respiratory Signals and Dosimetric Comparison

    Directory of Open Access Journals (Sweden)

    Jung Ae Lee

    2014-01-01

    Full Text Available Purpose. To investigate the effectiveness of respiratory guidance system in 4-dimensional computed tomography (4DCT based respiratory-gated radiation therapy (RGRT by comparing respiratory signals and dosimetric analysis of treatment plans. Methods. The respiratory amplitude and period of the free, the audio device-guided, and the complex system-guided breathing were evaluated in eleven patients with lung or liver cancers. The dosimetric parameters were assessed by comparing free breathing CT plan and 4DCT-based 30–70% maximal intensity projection (MIP plan. Results. The use of complex system-guided breathing showed significantly less variation in respiratory amplitude and period compared to the free or audio-guided breathing regarding the root mean square errors (RMSE of full inspiration (P=0.031, full expiration (P=0.007, and period (P=0.007. The dosimetric parameters including V5 Gy, V10 Gy, V20 Gy, V30 Gy, V40 Gy, and V50 Gy of normal liver or lung in 4DCT MIP plan were superior over free breathing CT plan. Conclusions. The reproducibility and regularity of respiratory amplitude and period were significantly improved with the complex system-guided breathing compared to the free or the audio-guided breathing. In addition, the treatment plan based on the 4D CT-based MIP images acquired with the complex system guided breathing showed better normal tissue sparing than that on the free breathing CT.

  18. Four-dimensional computed tomography: a method of assessing right ventricular outflow tract and pulmonary artery deformations throughout the cardiac cycle

    Energy Technology Data Exchange (ETDEWEB)

    Schievano, Silvia; Capelli, Claudio; Young, Carol; Lurz, Philipp; Nordmeyer, Johannes; Owens, Catherine; Bonhoeffer, Philipp; Taylor, Andrew M. [UCL, Institute of Child Health and Great, Ormond Street Hospital for Children, Cardiovascular Unit, London (United Kingdom)

    2011-01-15

    To characterise 3D deformations of the right ventricular outflow tract (RVOT)/ pulmonary arteries (PAs) during the cardiac cycle and estimate the errors of conventional 2D assessments. Contrast-enhanced, ECG-gated cardiovascular computed tomography (CT) findings were retrospectively analysed from 12 patients. The acquisition of 3D images over 10 phases of the cardiac cycle created a four-dimensional CT (4DCT) dataset. The datasets were reconstructed and deformation measured at various levels of the RVOT/PAs in both space and time. Section planes were either static or dynamic relative to the motion of the structures. 4DCT enabled measurement and characterisation of in vivo 3D changes of patients' RVOT/PA during the cardiac cycle. The studied patient population showed a wide range of RVOT/PA morphologies, sizes and dynamics that develop late after surgical repair of congenital heart disease. There were also significant differences in the measured cross-sectional areas of the structures between static and dynamic section planes (up to 150%, p < 0.05) secondary to large 3D displacements and rotations. 4DCT imaging data suggest high variability in RVOT/PA dynamics and significant errors in deformation measurements if 3D analysis is not carried out. These findings play an important role for the development of novel percutaneous approaches to pulmonary valve intervention. (orig.)

  19. Prostate displacement during transabdominal ultrasound image-guided radiotherapy assessed by real-time four-dimensional transperineal monitoring

    DEFF Research Database (Denmark)

    Baker, Mariwan; Behrens, Claus F.

    2015-01-01

    values ( 1 SD) (mm); inferior ( )-superior (I/S): (0.1 0.8); left ( )-right (L/R): (0.2 0.7); and anterior ( )-posterior (A/P): (0.1 1.0). The majority of the displacements were within 1 – 2 mm. Only two scans (5%) (A/P direction) and 16% of Euclidean distances were larger than 2.0 mm. The largest...

  20. The Four-Dimensional Symptom Questionnaire (4DSQ: a validation study of a multidimensional self-report questionnaire to assess distress, depression, anxiety and somatization

    Directory of Open Access Journals (Sweden)

    van Balkom Anton JLM

    2006-08-01

    Full Text Available Abstract Background The Four-Dimensional Symptom Questionnaire (4DSQ is a self-report questionnaire that has been developed in primary care to distinguish non-specific general distress from depression, anxiety and somatization. The purpose of this paper is to evaluate its criterion and construct validity. Methods Data from 10 different primary care studies have been used. Criterion validity was assessed by comparing the 4DSQ scores with clinical diagnoses, the GPs' diagnosis of any psychosocial problem for Distress, standardised psychiatric diagnoses for Depression and Anxiety, and GPs' suspicion of somatization for Somatization. ROC analyses and logistic regression analyses were used to examine the associations. Construct validity was evaluated by investigating the inter-correlations between the scales, the factorial structure, the associations with other symptom questionnaires, and the associations with stress, personality and social functioning. The factorial structure of the 4DSQ was assessed through confirmatory factor analysis (CFA. The associations with other questionnaires were assessed with Pearson correlations and regression analyses. Results Regarding criterion validity, the Distress scale was associated with any psychosocial diagnosis (area under the ROC curve [AUC] 0.79, the Depression scale was associated with major depression (AUC = 0.83, the Anxiety scale was associated with anxiety disorder (AUC = 0.66, and the Somatization scale was associated with the GPs' suspicion of somatization (AUC = 0.65. Regarding the construct validity, the 4DSQ scales appeared to have considerable inter-correlations (r = 0.35-0.71. However, 30–40% of the variance of each scale was unique for that scale. CFA confirmed the 4-factor structure with a comparative fit index (CFI of 0.92. The 4DSQ scales correlated with most other questionnaires measuring corresponding constructs. However, the 4DSQ Distress scale appeared to correlate with some other

  1. Investigation of pancreas tumour movements and of their potential markers by four-dimensional scanography: implication for image-guided radiotherapy; etude des mouvements des tumeurs du pancreas et de leurs marqueurs potentiels par scanographie quadridimensionnelle: implication pour la radiotherapie guidee par l'image

    Energy Technology Data Exchange (ETDEWEB)

    Huguet, F. [Hopital Tenon, Paris (France); Yorke, E.; Davidson, M.; Zhang, Z.; Jackson, A.; Mageras, G.; Wu, A.; Goodman, K. [Memorial Sloan-Kettering Cancer Center, New York (United States)

    2011-10-15

    The authors report the study which aimed at quantifying pancreas tumour movements induced by breathing by using four-dimensional scanography, and at assessing the reliability of biliary prosthesis, of intra-tumor fiducials, and of an external maker as position markers of the gross tumour volume (GTV). The authors analyzed scanography images acquired during the simulation of 22 patients treated for locally advanced pancreas cancer by intensity-modulated conformational irradiation with respiratory gating. Average movements in different directions have measured. Respiratory gating limits the GTV movement amplitude by 40 to 60 per cent. GTV movements are in good correlation with that of biliary prostheses and intra-tumor fiducials. Short communication

  2. Spinors in Four-Dimensional Spaces

    CERN Document Server

    Torres del Castillo, Gerardo F

    2010-01-01

    Without using the customary Clifford algebras frequently studied in connection with the representations of orthogonal groups, this book gives an elementary introduction to the two-component spinor formalism for four-dimensional spaces with any signature. Some of the useful applications of four-dimensional spinors, such as Yang–Mills theory, are derived in detail using illustrative examples. Key topics and features: • Uniform treatment of the spinor formalism for four-dimensional spaces of any signature, not only the usual signature (+ + + −) employed in relativity • Examples taken from Riemannian geometry and special or general relativity are discussed in detail, emphasizing the usefulness of the two-component spinor formalism • Exercises in each chapter • The relationship of Clifford algebras and Dirac four-component spinors is established • Applications of the two-component formalism, focusing mainly on general relativity, are presented in the context of actual computations Spinors in Four-Dim...

  3. Purely Four-dimensional Viable Anomaly Mediation

    CERN Document Server

    Harnik, R; Pierce, A T; Harnik, Roni; Murayama, Hitoshi; Pierce, Aaron

    2002-01-01

    Anomaly mediation of supersymmetry breaking solves the supersymmetric flavor problem thanks to its ultraviolet-insensitivity. However, it suffers from two problems: sleptons have negative masses-squared, and there are likely bulk moduli that spoil the framework. Here, we present the first fully ultraviolet-insensitive model of anomaly mediation with positive slepton masses-squared in a purely four-dimensional framework. Our model is based on the additional D-term contributions to the sparticle masses of Arkani-Hamed, Kaplan, HM, and Nomura, and the conformal sequestering mechanism of Luty and Sundrum.

  4. Purley four-dimensional viable anomaly mediation

    International Nuclear Information System (INIS)

    Anomaly mediation of supersymmetry breaking solves the supersymmetric flavor problem thanks to its ultraviolet-insensitivity. However, it suffers from two problems: sleptons have negative masses-squared, and there are likely bulk moduli that spoil the framework. Here, we present the first fully ultraviolet-insensitive model of anomaly mediation with positive slepton masses-squared in a purely four-dimensional framework. Our model is based on the additional D-term contributions to the sparticle masses, and the conformal sequestering mechanism. (author)

  5. Dynamic ventilation imaging from four-dimensional computed tomography

    Science.gov (United States)

    Guerrero, Thomas; Sanders, Kevin; Castillo, Edward; Zhang, Yin; Bidaut, Luc; Pan, Tinsu; Komaki, Ritsuko

    2006-02-01

    A novel method for dynamic ventilation imaging of the full respiratory cycle from four-dimensional computed tomography (4D CT) acquired without added contrast is presented. Three cases with 4D CT images obtained with respiratory gated acquisition for radiotherapy treatment planning were selected. Each of the 4D CT data sets was acquired during resting tidal breathing. A deformable image registration algorithm mapped each (voxel) corresponding tissue element across the 4D CT data set. From local average CT values, the change in fraction of air per voxel (i.e. local ventilation) was calculated. A 4D ventilation image set was calculated using pairs formed with the maximum expiration image volume, first the exhalation then the inhalation phases representing a complete breath cycle. A preliminary validation using manually determined lung volumes was performed. The calculated total ventilation was compared to the change in contoured lung volumes between the CT pairs (measured volume). A linear regression resulted in a slope of 1.01 and a correlation coefficient of 0.984 for the ventilation images. The spatial distribution of ventilation was found to be case specific and a 30% difference in mass-specific ventilation between the lower and upper lung halves was found. These images may be useful in radiotherapy planning.

  6. Dynamic ventilation imaging from four-dimensional computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, Thomas [Division of Radiation Oncology, University of Texas M D Anderson Cancer Center, Houston, TX 77030-4009 (United States); Sanders, Kevin [Division of Radiation Oncology, University of Texas M D Anderson Cancer Center, Houston, TX 77030-4009 (United States); Castillo, Edward [Department of Computational and Applied Mathematics, Rice University, Houston, TX (United States); Zhang Yin [Department of Computational and Applied Mathematics, Rice University, Houston, TX (United States); Bidaut, Luc [Division of Diagnostic Imaging, University of Texas M D Anderson Cancer Center, Houston, TX (United States); Pan Tinsu [Division of Diagnostic Imaging, University of Texas M D Anderson Cancer Center, Houston, TX (United States); Komaki, Ritsuko [Division of Radiation Oncology, University of Texas M D Anderson Cancer Center, Houston, TX 77030-4009 (United States)

    2006-02-21

    A novel method for dynamic ventilation imaging of the full respiratory cycle from four-dimensional computed tomography (4D CT) acquired without added contrast is presented. Three cases with 4D CT images obtained with respiratory gated acquisition for radiotherapy treatment planning were selected. Each of the 4D CT data sets was acquired during resting tidal breathing. A deformable image registration algorithm mapped each (voxel) corresponding tissue element across the 4D CT data set. From local average CT values, the change in fraction of air per voxel (i.e. local ventilation) was calculated. A 4D ventilation image set was calculated using pairs formed with the maximum expiration image volume, first the exhalation then the inhalation phases representing a complete breath cycle. A preliminary validation using manually determined lung volumes was performed. The calculated total ventilation was compared to the change in contoured lung volumes between the CT pairs (measured volume). A linear regression resulted in a slope of 1.01 and a correlation coefficient of 0.984 for the ventilation images. The spatial distribution of ventilation was found to be case specific and a 30% difference in mass-specific ventilation between the lower and upper lung halves was found. These images may be useful in radiotherapy planning.

  7. Quantum teleportation of four-dimensional qudits

    International Nuclear Information System (INIS)

    A protocol for the teleportation of arbitrary quantum states of four-dimensional qudits is presented. The qudit to be teleported is encoded in the combined state of two ensembles of atoms placed in a cavity at the sender's side. The receiver uses a similar setup, with his atoms prepared in a particular initial state. The teleportation protocol then consists of adiabatic mapping of the ensemble states onto photonic degrees of freedom, which are then directed onto a specific beam splitter and detection setup. For part of the measurement outcome, the qudit state is fully transferred to the receiver. Other detection events lead to partial teleportation or failed teleportation attempts. The interpretation of the different detection outcomes and possible ways of improving the full teleportation probability are discussed.

  8. N=3 four dimensional field theories

    CERN Document Server

    García-Etxebarria, Iñaki

    2015-01-01

    We introduce a class of four dimensional field theories constructed by quotienting ordinary $\\mathcal{N}=4$ $U(N)$ SYM by particular combinations of R-symmetry and $SL(2,\\mathbb{Z})$ automorphisms. These theories appear naturally on the worldvolume of D3 branes probing terminal singularities in F-theory, where they can be thought of as non-perturbative generalizations of the O3 plane. We focus on cases preserving only 12 supercharges, where the quotient gives rise to theories with coupling fixed at a value of order one. These constructions posses an unconventional large $N$ limit described by a non-trivial F-theory fibration with base $AdS_5\\times (S^5/\\mathbb{Z}_k)$. Upon reduction on a circle the $\\mathcal{N}=3$ theories flow to well-known $\\mathcal{N}=6$ ABJM theories.

  9. Four-dimensional unsubtraction with massive particles

    CERN Document Server

    Sborlini, German F R; Rodrigo, German

    2016-01-01

    We extend the four-dimensional unsubtraction method, which is based on the loop-tree duality (LTD), to deal with processes involving heavy particles. The method allows to perform the summation over degenerate IR configurations directly at integrand level in such a way that NLO corrections can be implemented directly in four space-time dimensions. We define a general momentum mapping between the real and virtual kinematics that accounts properly for the quasi-collinear configurations, and leads to an smooth massless limit. We illustrate the method first with an scalar toy example, and then analyse the case of the decay of a scalar or vector boson into a pair of massive quarks. The results presented in this paper are suitable for the application of the method to any multipartonic process.

  10. Assessment of psychological responses in patients about to receive radiotherapy

    International Nuclear Information System (INIS)

    Radiotherapy is considered to be associated with psychological distress. We assessed the mental status, anxiety, and the factors associated with these in cancer patients about to receive radiotherapy. Hospitalized patients about to receive radiotherapy participated. Psychological status was assessed by a psychiatrist, based on interview about the type of anxiety related to cancer or radiotherapy as well as self-rating questionnaires. Eligible data were collected from 94 patients. The incidence of mental disorders was 20%. The total mood disturbance scores were significantly higher in patients with poor performance status. The most common type of anxiety regarding radiotherapy was acute adverse effect, and the predictors were palliative treatment and living alone. Mental disorders, mood disturbance, and anxiety in patients cannot be neglected in radiation oncology practice. Especially careful attention should be paid to patients with these predictive factors. (author)

  11. Four-Dimensional Spin Foam Perturbation Theory

    Directory of Open Access Journals (Sweden)

    João Faria Martins

    2011-10-01

    Full Text Available We define a four-dimensional spin-foam perturbation theory for the BF-theory with a B∧B potential term defined for a compact semi-simple Lie group G on a compact orientable 4-manifold M. This is done by using the formal spin foam perturbative series coming from the spin-foam generating functional. We then regularize the terms in the perturbative series by passing to the category of representations of the quantum group U_q(g where g is the Lie algebra of G and q is a root of unity. The Chain-Mail formalism can be used to calculate the perturbative terms when the vector space of intertwiners Λ⊗Λ→A, where A is the adjoint representation of g, is 1-dimensional for each irrep Λ. We calculate the partition function Z in the dilute-gas limit for a special class of triangulations of restricted local complexity, which we conjecture to exist on any 4-manifold M. We prove that the first-order perturbative contribution vanishes for finite triangulations, so that we define a dilute-gas limit by using the second-order contribution. We show that Z is an analytic continuation of the Crane-Yetter partition function. Furthermore, we relate Z to the partition function for the F∧F theory.

  12. General flat four-dimensional world pictures and clock systems

    Science.gov (United States)

    Hsu, J. P.; Underwood, J. A.

    1978-01-01

    We explore the mathematical structure and the physical implications of a general four-dimensional symmetry framework which is consistent with the Poincare-Einstein principle of relativity for physical laws and with experiments. In particular, we discuss a four-dimensional framework in which all observers in different frames use one and the same grid of clocks. The general framework includes special relativity and a recently proposed new four-dimensional symmetry with a nonuniversal light speed as two special simple cases. The connection between the properties of light propagation and the convention concerning clock systems is also discussed, and is seen to be nonunique within the four-dimensional framework.

  13. Treatment assessment of radiotherapy using MR functional quantitative imaging

    Institute of Scientific and Technical Information of China (English)

    Zheng; Chang; Chunhao; Wang

    2015-01-01

    Recent developments in magnetic resonance(MR) functional quantitative imaging have made it a potentially powerful tool to assess treatment response in radiation therapy. With its abilities to capture functional information on underlying tissue characteristics, MR functional quantitative imaging can be valuable in assessing treatment response and as such to optimize therapeutic outcome. Various MR quantitative imaging techniques, including diffusion weighted imaging, diffusion tensor imaging, MR spectroscopy and dynamic contrastenhanced imaging, have been investigated and found useful for assessment of radiotherapy. However, various aspects including data reproducibility, interpretation of biomarkers, image quality and data analysis impose challenges on applications of MR functional quantitative imaging in radiotherapy assessment. All of these challenging issues shall be addressed to help us understand whether MR functional quantitative imaging is truly beneficial and contributes to future development of radiotherapy. It is evident that individualized therapy is the future direction of patient care. MR functional quantitative imaging might serves as an indispensable tool towards this promising direction.

  14. Successive superalgebraic truncations from the four-dimensional maximal supergravity

    CERN Document Server

    Kim, C H; Kim, K Y; Kim, Y; Kim, Chang Ho; Park, Young Jai; Kim, Kee Yong; Kim, Yongduk

    1994-01-01

    We study the four-dimensional {\\it N}=8 maximal supergravity in the context of Lie superalgebra SU(8/1). All possible successive superalgebraic truncations from four-dimensional {\\it N}=8 theory to {\\it N}=7, 6, \\cdots, 1 supergravity theories are systematically realized as sub-superalgebra chains of SU(8/1) by using the Kac-Dynkin weight techniques.

  15. Four-dimensional hilbert curves for R-trees

    DEFF Research Database (Denmark)

    Haverkort, Herman; Walderveen, Freek van

    2011-01-01

    according to the positions of their centers along a two-dimensional Hilbert space-filling curve. Alternatively, one may use the coordinates of the objects' bounding boxes to represent each object by a four-dimensional point, and sort these points along a four-dimensional Hilbert-type curve. In experiments...... by Kamel and Faloutsos and by Arge et al., the first solution consistently outperformed the latter when applied to point data, while the latter solution clearly outperformed the first on certain artificial rectangle data. These authors did not specify which four-dimensional Hilbert-type curve was used......; many exist. In this article, we show that the results of the previous articles can be explained by the choice of the four-dimensional Hilbert-type curve that was used and by the way it was rotated in four-dimensional space. By selecting a curve that has certain properties and choosing the right...

  16. On the four-dimensional formulation of dimensionally regulated amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Fazio, A.R. [Universidad Nacional de Colombia, Departamento de Fisica, Bogota (Colombia); Mastrolia, P. [Universita di Padova, Dipartimento di Fisica e Astronomia, Padua (Italy); Max-Planck-Institut fuer Physik, Munich (Germany); INFN, Padova (Italy); Mirabella, E. [Max-Planck-Institut fuer Physik, Munich (Germany); Torres Bobadilla, W.J. [Universidad Nacional de Colombia, Departamento de Fisica, Bogota (Colombia); Universita di Padova, Dipartimento di Fisica e Astronomia, Padua (Italy); INFN, Padova (Italy)

    2014-12-01

    Elaborating on the four-dimensional helicity scheme, we propose a pure four-dimensional formulation (FDF) of the d-dimensional regularization of one-loop scattering amplitudes. In our formulation particles propagating inside the loop are represented by massive internal states regulating the divergences. The latter obey Feynman rules containing multiplicative selection rules which automatically account for the effects of the extra-dimensional regulating terms of the amplitude. We present explicit representations of the polarization and helicity states of the four-dimensional particles propagating in the loop. They allow for a complete, four-dimensional, unitarity-based construction of d-dimensional amplitudes. Generalized unitarity within the FDF does not require any higher-dimensional extension of the Clifford and the spinor algebra. Finally we show how the FDF allows for the recursive construction of d-dimensional one-loop integrands, generalizing the four-dimensional open-loop approach. (orig.)

  17. Statistical Entropy of Four-Dimensional Extremal Black Holes

    OpenAIRE

    Maldacena, Juan; Strominger, Andrew

    1996-01-01

    String theory is used to count microstates of four-dimensional extremal black holes in compactifications with $N=4$ and $N=8$ supersymmetry. The result agrees for large charges with the Bekenstein-Hawking entropy.

  18. A four-dimensional petroleum systems model for the San Joaquin Basin Province, California: Chapter 12 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

    Science.gov (United States)

    Peters, Kenneth E.; Magoon, Leslie B.; Lampe, Carolyn; Scheirer, Allegra Hosford; Lillis, Paul G.; Gautier, Donald L.

    2008-01-01

    A calibrated numerical model depicts the geometry and three-dimensional (3-D) evolution of petroleum systems through time (4-D) in a 249 x 309 km (155 x 192 mi) area covering all of the San Joaquin Basin Province of California. Model input includes 3-D structural and stratigraphic data for key horizons and maps of unit thickness, lithology, paleobathymetry, heat flow, original total organic carbon, and original Rock-Eval pyrolysis hydrogen index for each source rock. The four principal petroleum source rocks in the basin are the Miocene Antelope shale of Graham and Williams (1985; hereafter referred to as Antelope shale), the Eocene Kreyenhagen Formation, the Eocene Tumey formation of Atwill (1935; hereafter referred to as Tumey formation), and the Cretaceous to Paleocene Moreno Formation. Due to limited Rock-Eval/total organic carbon data, the Tumey formation was modeled using constant values of original total organic carbon and original hydrogen index. Maps of original total organic carbon and original hydrogen index were created for the other three source rocks. The Antelope shale was modeled using Type IIS kerogen kinetics, whereas Type II kinetics were used for the other source rocks. Four-dimensional modeling and geologic field evidence indicate that maximum burial of the three principal Cenozoic source rocks occurred in latest Pliocene to Holocene time. For example, a 1-D extraction of burial history from the 4-D model in the Tejon depocenter shows that the bottom of the Antelope shale source rock began expulsion (10 percent transformation ratio) about 4.6 Ma and reached peak expulsion (50 percent transformation ratio) about 3.6 Ma. Except on the west flank of the basin, where steep dips in outcrop and seismic data indicate substantial uplift, little or no section has been eroded. Most petroleum migration occurred during late Cenozoic time in distinct stratigraphic intervals along east-west pathways from pods of active petroleum source rock in the Tejon and

  19. Anisotropic Four-Dimensional NS-NS String Cosmology

    CERN Document Server

    Chen, C M; Mak, M K; Chen, Chiang-Mei

    2001-01-01

    An anisotropic (Bianchi type I) cosmology is considered in the four-dimensional NS-NS sector of low-energy effective string theory coupled to a dilaton and an axion-like $H$-field within a de Sitter-Einstein frame background. The time evolution of this Universe is discussed in both the Einstein and string frames.

  20. Vector particles tunneling from four-dimensional Schwarzschild black holes

    Science.gov (United States)

    Chen, Ge-Rui; Zhou, Shiwei; Huang, Yong-Chang

    2015-05-01

    Vector particles' Hawking radiation from a four-dimensional Schwarzschild black hole is investigated. By applying the WKB approximation and the Hamilton-Jacobi ansatz to the Proca equation, we obtain the tunneling spectrum of vector particles and the expected Hawking temperature.

  1. Four-dimensional conformal field theory using quaternions

    CERN Document Server

    Giardino, Sergio

    2015-01-01

    We build a four-dimensional quaternion-parametrized conformal field theory (QCFT) using quaternion holomorphic functions as the generators of quaternionic conformal transformations. Taking the two-dimensional complex-parametrized conformal field theory (CCFT) as our model, we study the stress tensor, the conserved charge, the symmetry generators, the quantization conditions and several operator product expansions (OPE's). Future applications also are addressed.

  2. The scalar curvature problem on the four dimensional half sphere

    CERN Document Server

    Ben-Ayed, M; El-Mehdi, K

    2003-01-01

    In this paper, we consider the problem of prescribing the scalar curvature under minimal boundary conditions on the standard four dimensional half sphere. We provide an Euler-Hopf type criterion for a given function to be a scalar curvature for some metric conformal to the standard one. Our proof involves the study of critical points at infinity of the associated variational problem.

  3. A linear solution to the effective four-dimensionality problem

    OpenAIRE

    Trifonov, Vladimir

    2003-01-01

    In this note we formalize certain aspects of observation process in an attempt to link the logic of the observer with properties of the observables structures. It is shown that an observer with Boolean logic perceives her environment as a four-dimensional Lorentzian manifold.

  4. Concurrent Boost with Adjuvant Breast Hypofractionated Radiotherapy and Toxicity Assessment

    Directory of Open Access Journals (Sweden)

    Mona M. Sayed

    2015-01-01

    Full Text Available Background: The use of shorter radiotherapy schedules has an economic and logistic advantage for radiotherapy departments, as well as a high degree of patient convenience. The aim of this study is to assess the acute and short-term late toxicities of a hypofractionated radiotherapy schedule with a concomitant boost. Methods: We enrolled 57 eligible patients as group A. These patients received 42.5 Gy in 16 fractions of 2.66 Gy each to the whole breast over 3.2 weeks. A concomitant electron boost of 12 Gy in 16 fractions was also administered which gave an additional 0.75 Gy daily to the lumpectomy area for a total radiation dose of 54.5 Gy. Toxicity was recorded at three weeks and at three months for this group as well as for a control group (group B. The control group comprised 76 eligible patients treated conventionally with 50 Gy to the whole breast over five weeks followed by a sequential electron boost of 12 Gy in 2 Gy per fraction. Results: There were no statistically significant differences observed in the incidence of acute skin toxicity, breast pain, and edema recorded at three weeks or pigmentation and fibrosis recorded at three months between the two groups (P0.05. Conclusion: The results of this study suggest there are no increased acute and shortterm late toxicities affiliated with the hypofractionated schedule plus a concomitant boost as prescribed compared to the conventional fractionation of adjuvant breast radiotherapy. Large randomized trials and long-term follow-up are needed to confirm these favorable findings.

  5. Radiotherapy

    International Nuclear Information System (INIS)

    The need for radiotherapy research is exemplified by the 100,000 cancer patients who will fail treatment locally and/or regionally annually for the next several years but who would benefit from better local treatment modalities. Theoretically, all of the areas of investigation discussed in this projection paper have the potential to significantly improve local-regional treatment of cancer by radiotherapy alone or in combination with other modalities. In many of the areas of investigation discussed in this paper encouraging results have been obtained in cellular and animal tumor studies and in limited studies in humans as well. In the not too distant future the number of patients who would benefit from better local control may increase by tens of thousands if developments in chemotherapy and/or immunotherapy provide a means to eradicate disseminated microscopic foci of cancer. Thus the efforts to improve local-regional control take on even greater significance

  6. Manual control displays for a four-dimensional landing approach

    Science.gov (United States)

    Silverthorn, J. T.; Swaim, R. L.

    1975-01-01

    Six instrument rated pilots flew a STOL fixed base simulator to study the effectiveness of three displays for a four dimensional approach. The three examined displays were a digital readout of forward position error, a digital speed command, and an analog display showing forward position error and error prediction. A flight director was used in all conditions. All test runs were for a typical four dimensional approach in moderate turbulence that included a change in commanded ground speed, a change in flight path angle, and two standard rate sixty degree turns. Use of the digital forward position error display resulted in large overshoot in the forward position error. Some type of lead (rate or prediction information) was shown to be needed. The best overall performance was obtained using the speed command display. It was demonstrated that curved approaches can be flown with relative ease.

  7. Integrable four-dimensional symplectic maps of standard type

    CERN Document Server

    McLachlan, R I

    1993-01-01

    We search for rational, four-dimensional maps of standard type (x_{n+1} - 2x_n + x_{n-1} = eps f(x,eps)) possessing one or two polynomial integrals. There are no non-trivial maps corresponding to cubic oscillators, but we find a four-parameter family of such maps corresponding to quartic oscillators. This seems to be the only such example.

  8. Mathieu moonshine in four dimensional N=1 theories

    International Nuclear Information System (INIS)

    We show that the recently discovered Mathieu moonshine plays a role for certain four dimensional theories with N=1 supersymmetry. These theories are obtained from the E8×E8 heterotic string theory by compactifying on toroidal orbifolds. We find that a universal contribution to the holomorphic gauge kinetic function can be expanded in such a way that the expansion coefficients are the dimensions of representations of the Mathieu group M24

  9. The transfer matrix in four dimensional causal dynamical triangulations

    OpenAIRE

    Ambjo̸rn, J.; Gizbert-Studnicki, J.(Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. prof. Stanislawa Lojasiewicza 11, Krakow, PL 30-348, Poland); Görlich, A.T.; Jurkiewicz, J.; Loll, R.

    2013-01-01

    The Causal Dynamical Triangulation model of quantum gravity (CDT) is a proposition to evaluate the path integral over space-time geometries using a lattice regularization with a discrete proper time and geometries realized as simplicial manifolds. The model admits a Wick rotation to imaginary time for each space-time configuration. Using computer simulations we determined the phase structure of the model and discovered that it predicts a de Sitter phase with a four-dimensional spherical semi-...

  10. Four-dimensional pseudo-Riemannian homogeneous Ricci solitons

    OpenAIRE

    Calvaruso, Giovanni; Fino, Anna

    2011-01-01

    We consider four-dimensional homogeneous pseudo-Riemannian manifolds with non-trivial isotropy and completely classify the cases giving rise to non-trivial homogeneous Ricci solitons. In particular, we show the existence of non-compact homogeneous (and also invariant) pseudo-Riemannian Ricci solitons which are not isometric to solvmanifolds, and of conformally flat homogeneous pseudo-Riemannian Ricci solitons which are not symmetric.

  11. An assessment of radiotherapy dosimeters based on CVD grown diamond

    CERN Document Server

    Ramkumar, S; Conway, J; Whitehead, A J; Sussman, R S; Hill, G; Walker, S

    2001-01-01

    Diamond is potentially a very suitable material for use as a dosimeter for radiotherapy. Its radiation hardness, the near tissue equivalence and chemical inertness are some of the characteristics of diamond, which make it well suited for its application as a dosimeter. Recent advances in the synthesis of diamond by chemical vapour deposition (CVD) technology have resulted in the improvement in the quality of material and increased its suitability for radiotherapy applications. We report in this paper, the response of prototype dosimeters based on two different types (CVD1 and CVD2) of CVD diamond to X-rays. The diamond devices were assessed for sensitivity, dependence of response on dose and dose rate, and compared with a Scanditronix silicon photon diode and a PTW natural diamond dosimeter. The diamond devices of CVD1 type showed an initial increase in response with dose, which saturates after approx 6 Gy. The diamond devices of CVD2 type had a response at low fields (1162.8 V/cm), the CVD2-type devices show...

  12. Local bifurcation analysis of a four-dimensional hyperchaotic system

    Institute of Scientific and Technical Information of China (English)

    Wu Wen-Juan; Chen Zeng-Qiang; Yuan Zhu-Zhi

    2008-01-01

    Local bifurcation phenomena in a four-dimensional continuous hyperchaotic system, which has rich and complex dynamical behaviours, are analysed. The local bifurcations of the system are investigated by utilizing the bifurcation theory and the centre manifold theorem, and thus the conditions of the existence of pitchfork bifurcation and Hopf bifurcation are derived in detail. Numerical simulations are presented to verify the theoretical analysis, and they show some interesting dynamics, including stable periodic orbits emerging from the new fixed points generated by pitchfork bifurcation, coexistence of a stable limit cycle and a chaotic attractor, as well as chaos within quite a wide parameter region.

  13. Four-dimensional optical manipulation of colloidal particles

    DEFF Research Database (Denmark)

    Rodrigo, P.J.; Daria, V.R.; Glückstad, J.

    2005-01-01

    We transform a TEM00 laser mode into multiple counterpropagating optical traps to achieve four-dimensional simultaneous manipulation of multiple particles. Efficient synthesis and dynamic control of the counterpropagating-beam traps is carried out via the generalized phase contrast method......, and a spatial polarization-encoding scheme. Our experiments genuinely demonstrate real-time, interactive particle-position control for forming arbitrary volumetric constellations and complex three-dimensional trajectories of multiple particles. This opens up doors for cross-disciplinary cutting-edge research...

  14. MRI assessment of cervical cancer for adaptive radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, Johannes C.A.; Schirl, Gertrude; Baldinger, Anja; Poetter, Richard [Medical Univ. of Vienna (Austria). Dept. of Radiotherapy; Helbich, Thomas H. [Medical Univ. of Vienna (Austria). Dept of Radiology

    2009-05-15

    Purpose: To assess the importance of the information obtained from MRI for adaptive cervix cancer radiotherapy. Patients and methods: 49 patients with cervix cancer, treated by external-beam radiotherapy (EBRT) and MRI-assisted high-dose-rate brachytherapy {+-} concomitant cisplatin, underwent MRI at diagnosis and at the time of brachytherapy fractions. 190 MRI examinations were performed. Pretreatment scans were correlated with clinical examination (CE) findings. Measurements in 3-D of the tumor extension and also of the distance from the tumor to the pelvic side wall were performed using both MRI and CE. The tumor volume regression induced initially by EBRT and the subsequent regression after each brachytherapy fraction were assessed. Results: MRI and CE showed 92% agreement in overall parametrial staging and 73% agreement in terms of vaginal involvement. There was, however, disagreement in parametrial side (right/left) classification in 25% of the parametria examined. These were patients with unilateral displacement of the cervix and contralateral invasion of the parametrium. The mean tumor volume on the pretreatment MRI scan (GTVD) was 61 cm{sup 3}. At the time of the four brachytherapy fractions the mean was 16 cm{sup 3}, 10 cm{sup 3}, 9 cm{sup 3}, and 8 cm{sup 3}, defined as the GTVBT plus the gray zones in the parametria. Conclusion: CE and MRI findings agree well in terms of overall staging. The clinical assessment of side-specific parametrial invasion improved when having access to the additional knowledge obtained from MRI. The greatest decrease in tumor volume occurs during EBRT, whereas tumor regression between the first and subsequent brachytherapy fractions is minor. (orig.)

  15. Platonic solids generate their four-dimensional analogues

    CERN Document Server

    Dechant, Pierre-Philippe

    2013-01-01

    In this paper, we show how regular convex 4-polytopes - the analogues of the Platonic solids in four dimensions - can be constructed from three-dimensional considerations concerning the Platonic solids alone. Via the Cartan-Dieudonne theorem, the reflective symmetries of the Platonic solids generate rotations. In a Clifford algebra framework, the space of spinors generating such three-dimensional rotations has a natural four-dimensional Euclidean structure. The spinors arising from the Platonic Solids can thus in turn be interpreted as vertices in four-dimensional space, giving a simple construction of the 4D polytopes 16-cell, 24-cell, the F_4 root system and the 600-cell. In particular, these polytopes have `mysterious' symmetries, that are almost trivial when seen from the three-dimensional spinorial point of view. In fact, all these induced polytopes are also known to be root systems and thus generate rank-4 Coxeter groups, which can be shown to be a general property of the spinor construction. These cons...

  16. Benchmarking Dosimetric Quality Assessment of Prostate Intensity-Modulated Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: To benchmark the dosimetric quality assessment of prostate intensity-modulated radiotherapy and determine whether the quality is influenced by disease or treatment factors. Patients and Methods: We retrospectively analyzed the data from 155 consecutive men treated radically for prostate cancer using intensity-modulated radiotherapy to 78 Gy between January 2007 and March 2009 across six radiotherapy treatment centers. The plan quality was determined by the measures of coverage, homogeneity, and conformity. Tumor coverage was measured using the planning target volume (PTV) receiving 95% and 100% of the prescribed dose (V95% and V100%, respectively) and the clinical target volume (CTV) receiving 95% and 100% of the prescribed dose. Homogeneity was measured using the sigma index of the PTV and CTV. Conformity was measured using the lesion coverage factor, healthy tissue conformity index, and the conformity number. Multivariate regression models were created to determine the relationship between these and T stage, risk status, androgen deprivation therapy use, treatment center, planning system, and treatment date. Results: The largest discriminatory measurements of coverage, homogeneity, and conformity were the PTV V95%, PTV sigma index, and conformity number. The mean PTV V95% was 92.5% (95% confidence interval, 91.3–93.7%). The mean PTV sigma index was 2.10 Gy (95% confidence interval, 1.90–2.20). The mean conformity number was 0.78 (95% confidence interval, 0.76–0.79). The treatment center independently influenced the coverage, homogeneity, and conformity (all p 95% only, with it being better at the start (p = .013). Risk status, T stage, and the use of androgen deprivation therapy did not influence any aspect of plan quality. Conclusion: Our study has benchmarked measures of coverage, homogeneity, and conformity for the treatment of prostate cancer using IMRT. The differences seen between centers and planning systems and the coverage deterioration

  17. Benchmarking Dosimetric Quality Assessment of Prostate Intensity-Modulated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Senthi, Sashendra, E-mail: sasha.senthi@petermac.org [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Gill, Suki S. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Haworth, Annette; Kron, Tomas; Cramb, Jim [Department of Physical Sciences, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Rolfo, Aldo [Radiation Therapy Services, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Thomas, Jessica [Biostatistics and Clinical Trials, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Duchesne, Gillian M. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Hamilton, Christopher H.; Joon, Daryl Lim [Radiation Oncology Department, Austin Repatriation Hospital, Heidelberg, VIC (Australia); Bowden, Patrick [Radiation Oncology Department, Tattersall' s Cancer Center, East Melbourne, VIC (Australia); Foroudi, Farshad [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia)

    2012-02-01

    Purpose: To benchmark the dosimetric quality assessment of prostate intensity-modulated radiotherapy and determine whether the quality is influenced by disease or treatment factors. Patients and Methods: We retrospectively analyzed the data from 155 consecutive men treated radically for prostate cancer using intensity-modulated radiotherapy to 78 Gy between January 2007 and March 2009 across six radiotherapy treatment centers. The plan quality was determined by the measures of coverage, homogeneity, and conformity. Tumor coverage was measured using the planning target volume (PTV) receiving 95% and 100% of the prescribed dose (V{sub 95%} and V{sub 100%}, respectively) and the clinical target volume (CTV) receiving 95% and 100% of the prescribed dose. Homogeneity was measured using the sigma index of the PTV and CTV. Conformity was measured using the lesion coverage factor, healthy tissue conformity index, and the conformity number. Multivariate regression models were created to determine the relationship between these and T stage, risk status, androgen deprivation therapy use, treatment center, planning system, and treatment date. Results: The largest discriminatory measurements of coverage, homogeneity, and conformity were the PTV V{sub 95%}, PTV sigma index, and conformity number. The mean PTV V{sub 95%} was 92.5% (95% confidence interval, 91.3-93.7%). The mean PTV sigma index was 2.10 Gy (95% confidence interval, 1.90-2.20). The mean conformity number was 0.78 (95% confidence interval, 0.76-0.79). The treatment center independently influenced the coverage, homogeneity, and conformity (all p < .0001). The planning system independently influenced homogeneity (p = .038) and conformity (p = .021). The treatment date independently influenced the PTV V{sub 95%} only, with it being better at the start (p = .013). Risk status, T stage, and the use of androgen deprivation therapy did not influence any aspect of plan quality. Conclusion: Our study has benchmarked measures

  18. Four-dimensional black holes in Einsteinian cubic gravity

    CERN Document Server

    Bueno, Pablo

    2016-01-01

    We construct static and spherically symmetric generalizations of the Schwarzschild- and Reissner-Nordstr\\"om-(Anti) de Sitter (RN-(A)dS) black-hole solutions in four-dimensional Einsteinian cubic gravity (ECG). The solutions are determined by a single blackening factor which satisfies a non-linear second-order differential equation. Interestingly, we are able to compute independently the Hawking temperature $T$, the Wald entropy $\\mathsf{S}$ and the Abbott-Deser mass $M$ of the solutions analytically as functions of the horizon radius and the ECG coupling constant $\\lambda$. Using these we show that the first law of black-hole mechanics is exactly satisfied. Some of the solutions have positive specific heat, which makes them thermodynamically stable, even in the uncharged and asymptotically flat case.

  19. The effective action in four-dimensional CDT

    CERN Document Server

    Gizbert-Studnicki, Jakub

    2015-01-01

    We present recent results concerning the measurement and analysis of the effective action in four-dimensional Causal Dynamical Triangulations. The action describes quantum fluctuations of the spatial volume of the CDT universe (or alternatively the scale factor) after integrating out other degrees of freedom. We use the covariance of volume fluctuations to measure and parametrize the effective action inside the de Sitter phase, also called the C phase. We show that the action is consistent with a simple discretization of the minisuperspace action (with a reversed overall sign). We discuss possible subleading corrections and show how to construct a more complicated effective action comprising both integer and half-integer discrete proper time layers. We introduce a new method of the effective action measurement based on the transfer matrix. We show that the results of the new method are fully consistent with the covariance matrix method inside the de Sitter phase. We use the new method to measure the effective...

  20. Decomposable medium conditions in four-dimensional representation

    CERN Document Server

    Lindell, Ismo V; Favaro, Alberto

    2011-01-01

    The well-known TE/TM decomposition of time-harmonic electromagnetic fields in uniaxial anisotropic media is generalized in terms of four-dimensional differential-form formalism by requiring that the field two-form satisfies an orthogonality condition with respect to two given bivectors. Conditions for the electromagnetic medium in which such a decomposition is possible are derived and found to define three subclasses of media. It is shown that the previously known classes of generalized Q-media and generalized P-media are particular cases of the proposed decomposable media (DCM) associated to a quadratic equation for the medium dyadic. As a novel solution, another class of special decomposable media (SDCM) is defined by a linear dyadic equation. The paper further discusses the properties of medium dyadics and plane-wave propagation in all the identified cases of DCM and SDCM.

  1. Implementation of a risk assessment tool based on a probabilistic safety assessment developed for radiotherapy practices

    Energy Technology Data Exchange (ETDEWEB)

    Paz, A.; Godinez, V.; Lopez, R., E-mail: abpaz@cnsns.gob.m [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Barragan No. 779, Col. Narvarte, 03020 Mexico D. F. (Mexico)

    2010-10-15

    The present work describes the implementation process and main results of the risk assessment to the radiotherapy practices with Linear Accelerators (Linac), with cobalt 60, and with brachytherapy. These evaluations were made throughout the risk assessment tool for radiotherapy practices SEVRRA (risk evaluation system for radiotherapy), developed at the Mexican National Commission in Nuclear Safety and Safeguards derived from the outcome obtained with the Probabilistic Safety Analysis developed at the Ibero-American Regulators Forum for these radiotherapy facilities. The methodology used is supported by risk matrices method, a mathematical tool that estimates the risk to the patient, radiation workers and public from mechanical failures, mis calibration of the devices, human mistakes, and so. The initiating events are defined as those undesirable events that, together with other failures, can produce a delivery of an over-dose or an under-dose of the medical prescribed dose, to the planned target volume, or a significant dose to non prescribed human organs. Initiating events frequency and reducer of its frequency (actions intended to avoid the accident) are estimated as well as robustness of barriers to those actions, such as mechanical switches, which detect and prevent the accident from occurring. The spectrum of the consequences is parameterized, and the actions performed to reduce the consequences are identified. Based on this analysis, a software tool was developed in order to simplify the evaluations to radiotherapy installations and it has been applied as a first step forward to some Mexican installations, as part of a national implementation process, the final goal is evaluation of all Mexican facilities in the near future. The main target and benefits of the SEVRRA implementation are presented in this paper. (Author)

  2. An explicit four-dimensional variational data assimilation method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new data assimilation method called the explicit four-dimensional variational (4DVAR) method is proposed. In this method, the singular value decomposition (SVD) is used to construct the orthogonal basis vectors from a forecast ensemble in a 4D space. The basis vectors represent not only the spatial structure of the analysis variables but also the temporal evolution. After the analysis variables are ex-pressed by a truncated expansion of the basis vectors in the 4D space, the control variables in the cost function appear explicitly, so that the adjoint model, which is used to derive the gradient of cost func-tion with respect to the control variables, is no longer needed. The new technique significantly simpli-fies the data assimilation process. The advantage of the proposed method is demonstrated by several experiments using a shallow water numerical model and the results are compared with those of the conventional 4DVAR. It is shown that when the observation points are very dense, the conventional 4DVAR is better than the proposed method. However, when the observation points are sparse, the proposed method performs better. The sensitivity of the proposed method with respect to errors in the observations and the numerical model is lower than that of the conventional method.

  3. Four-dimensional unsubtraction from the loop-tree duality

    CERN Document Server

    Sborlini, German F R; Hernandez-Pinto, Roger; Rodrigo, German

    2016-01-01

    We present a new algorithm to construct a purely four dimensional representation of higher-order perturbative corrections to physical cross-sections at next-to-leading order (NLO). The algorithm is based on the loop-tree duality (LTD), and it is implemented by introducing a suitable mapping between the external and loop momenta of the virtual scattering amplitudes with the external momenta of the real emission corrections. In this way, the sum over degenerate infrared states is performed at the integrand level and the cancellation of infrared divergences occurs locally without introducing subtraction counter-terms to deal with soft and final-state collinear singularities. The dual representation of ultraviolet counter-terms is also discussed in detail, in particular for self-energy contributions. The method is first illustrated with the scalar three-point function, before proceeding with the calculation of the physical cross-section for $\\gamma^* \\to q \\bar{q}(g)$, at its generalisation to multi-leg processes...

  4. An explicit four-dimensional variational data assimilation method

    Institute of Scientific and Technical Information of China (English)

    QIU ChongJian; ZHANG Lei; SHAO AiMei

    2007-01-01

    A new data assimilation method called the explicit four-dimensional variational (4DVAR) method is proposed. In this method, the singular value decomposition (SVD) is used to construct the orthogonal basis vectors from a forecast ensemble in a 4D space. The basis vectors represent not only the spatial structure of the analysis variables but also the temporal evolution. After the analysis variables are expressed by a truncated expansion of the basis vectors in the 4D space, the control variables in the cost function appear explicitly, so that the adjoint model, which is used to derive the gradient of cost function with respect to the control variables, is no longer needed. The new technique significantly simplifies the data assimilation process. The advantage of the proposed method is demonstrated by several experiments using a shallow water numerical model and the results are compared with those of the conventional 4DVAR. It is shown that when the observation points are very dense, the conventional 4DVAR is better than the proposed method. However, when the observation points are sparse, the proposed method performs better. The sensitivity of the proposed method with respect to errors in the observations and the numerical model is lower than that of the conventional method.

  5. An economical approach to four-dimensional variational data assimilation

    Science.gov (United States)

    Wang, Bin; Liu, Juanjuan; Wang, Shudong; Cheng, Wei; Juan, Liu; Liu, Chengsi; Xiao, Qingnong; Kuo, Ying-Hwa

    2010-07-01

    Four-dimensional variational data assimilation (4DVar) is one of the most promising methods to provide optimal analysis for numerical weather prediction (NWP). Five national NWP centers in the world have successfully applied 4DVar methods in their global NWPs, thanks to the increment method and adjoint technique. However, the application of 4DVar is still limited by the computer resources available at many NWP centers and research institutes. It is essential, therefore, to further reduce the computational cost of 4DVar. Here, an economical approach to implement 4DVar is proposed, using the technique of dimensionreduced projection (DRP), which is called "DRP-4DVar." The proposed approach is based on dimension reduction using an ensemble of historical samples to define a subspace. It directly obtains an optimal solution in the reduced space by fitting observations with historical time series generated by the model to form consistent forecast states, and therefore does not require implementation of the adjoint of tangent linear approximation. To evaluate the performance of the DRP-4DVar on assimilating different types of mesoscale observations, some observing system simulation experiments are conducted using MM5 and a comparison is made between adjoint-based 4DVar and DRP-4DVar using a 6-hour assimilation window.

  6. A method for the reconstruction of four-dimensional synchronized CT scans acquired during free breathing

    International Nuclear Information System (INIS)

    Breathing motion is a significant source of error in radiotherapy treatment planning for the thorax and upper abdomen. Accounting for breathing motion has a profound effect on the size of conformal radiation portals employed in these sites. Breathing motion also causes artifacts and distortions in treatment planning computed tomography (CT) scans acquired during free breathing and also causes a breakdown of the assumption of the superposition of radiation portals in intensity-modulated radiation therapy, possibly leading to significant dose delivery errors. Proposed voluntary and involuntary breath-hold techniques have the potential for reducing or eliminating the effects of breathing motion, however, they are limited in practice, by the fact that many lung cancer patients cannot tolerate holding their breath. We present an alternative solution to accounting for breathing motion in radiotherapy treatment planning, where multislice CT scans are collected simultaneously with digital spirometry over many free breathing cycles to create a four-dimensional (4-D) image set, where tidal lung volume is the additional dimension. An analysis of this 4-D data leads to methods for digital-spirometry, based elimination or accounting of breathing motion artifacts in radiotherapy treatment planning for free breathing patients. The 4-D image set is generated by sorting free-breathing multislice CT scans according to user-defined tidal-volume bins. A multislice CT scanner is operated in the cine mode, acquiring 15 scans per couch position, while the patient undergoes simultaneous digital-spirometry measurements. The spirometry is used to retrospectively sort the CT scans by their correlated tidal lung volume within the patient's normal breathing cycle. This method has been prototyped using data from three lung cancer patients. The actual tidal lung volumes agreed with the specified bin volumes within standard deviations ranging between 22 and 33 cm3. An analysis of sagittal and

  7. Four-dimensional IMRT treatment planning using a DMLC motion-tracking algorithm

    Science.gov (United States)

    Suh, Yelin; Sawant, Amit; Venkat, Raghu; Keall, Paul J.

    2009-06-01

    The purpose of this study is to develop a four-dimensional (4D) intensity-modulated radiation therapy (IMRT) treatment-planning method by modifying and applying a dynamic multileaf collimator (DMLC) motion-tracking algorithm. The 4D radiotherapy treatment scenario investigated is to obtain a 4D treatment plan based on a 4D computed tomography (CT) planning scan and to have the delivery flexible enough to account for changes in tumor position during treatment delivery. For each of 4D CT planning scans from 12 lung cancer patients, a reference phase plan was created; with its MLC leaf positions and three-dimensional (3D) tumor motion, the DMLC motion-tracking algorithm generated MLC leaf sequences for the plans of other respiratory phases. Then, a deformable dose-summed 4D plan was created by merging the leaf sequences of individual phase plans. Individual phase plans, as well as the deformable dose-summed 4D plan, are similar for each patient, indicating that this method is dosimetrically robust to the variations of fractional time spent in respiratory phases on a given 4D CT planning scan. The 4D IMRT treatment-planning method utilizing the DMLC motion-tracking algorithm explicitly accounts for 3D tumor motion and thus hysteresis and nonlinear motion, and is deliverable on a linear accelerator.

  8. Commissioning and quality assurance of Calypso four-dimensional target localization system in linear accelerator facility.

    Science.gov (United States)

    Muralidhar, K R; Komanduri, Krishna; Rout, Birendra Kumar; Ramesh, K K D

    2013-07-01

    Four dimensional (4D) target localization system (Calypso System) was installed at our hospital, which is equipped with Beacon Transponders, Console, Electromagnetic Array, Optical System, Tracking Station, Treatment table overlay, and Calypso kVue Couch top. The objective of this presentation is to describe the results of commissioning measurements carried out on the Calypso System to verify the manufacturer specifications and also to evolve a quality assurance (QA) procedure which can be used to test its performance routinely. The QA program consists of a series of tests (QA for checking the calibration or system accuracy, Camera Calibration with L-frame fixture, Camera Calibration with T-frame fixture, System calibration Fixture targets test, Localization, and Tracking). These tests were found to be useful to assess the performance of the Calypso System.

  9. Model-based risk assessment for motion effects in 3D radiotherapy of lung tumors

    Science.gov (United States)

    Werner, René; Ehrhardt, Jan; Schmidt-Richberg, Alexander; Handels, Heinz

    2012-02-01

    Although 4D CT imaging becomes available in an increasing number of radiotherapy facilities, 3D imaging and planning is still standard in current clinical practice. In particular for lung tumors, respiratory motion is a known source of uncertainty and should be accounted for during radiotherapy planning - which is difficult by using only a 3D planning CT. In this contribution, we propose applying a statistical lung motion model to predict patients' motion patterns and to estimate dosimetric motion effects in lung tumor radiotherapy if only 3D images are available. Being generated based on 4D CT images of patients with unimpaired lung motion, the model tends to overestimate lung tumor motion. It therefore promises conservative risk assessment regarding tumor dose coverage. This is exemplarily evaluated using treatment plans of lung tumor patients with different tumor motion patterns and for two treatment modalities (conventional 3D conformal radiotherapy and step-&- shoot intensity modulated radiotherapy). For the test cases, 4D CT images are available. Thus, also a standard registration-based 4D dose calculation is performed, which serves as reference to judge plausibility of the modelbased 4D dose calculation. It will be shown that, if combined with an additional simple patient-specific breathing surrogate measurement (here: spirometry), the model-based dose calculation provides reasonable risk assessment of respiratory motion effects.

  10. Slow gantry rotation acquisition technique for on-board four-dimensional digital tomosynthesis

    International Nuclear Information System (INIS)

    Purpose: Four-dimensional cone-beam computed tomography (4D CBCT) has been investigated for motion imaging in the radiotherapy treatment room. The drawbacks of 4D CBCT are long scan times and high imaging doses. The aims of this study were to develop and investigate a slow gantry rotation acquisition protocol for four-dimensional digital tomosynthesis (4D DTS) as a faster, lower dose alternative to 4D CBCT. Methods: This technique was implemented using an On-Board Imager kV imaging system (Varian Medical Systems, Palo Alto, CA) mounted on the gantry of a linear accelerator. The general procedure for 4D DTS imaging using slow gantry rotation acquisition consists of the following steps: (1) acquire projections over a limited gantry rotation angle in a single motion with constant frame rate and gantry rotation speed; (2) generate a respiratory signal and temporally match projection images with appropriate points from the respiratory signal; (3) use the respiratory signal to assign phases to each of the projection images; (4) sort projection images into phase bins; and (5) reconstruct phase images. Phantom studies were conducted to validate theoretically derived relationships between acquisition and respiratory parameters. Optimization of acquisition parameters was then conducted by simulating lung scans using patient data. Lung tumors with approximate volumes ranging from 0.12 to 1.53 cm3 were studied. Results: A protocol for slow gantry rotation 4D DTS was presented. Equations were derived to express relationships between acquisition parameters (frame rate, phase window, and angular intervals between projections), respiratory cycle durations, and resulting acquisition times and numbers of projections. The phantom studies validated the relationships, and the patient studies resulted in determinations of appropriate acquisition parameters. The phase window must be set according to clinical goals. For 10% phase windows, we found that appropriate frame rates ranging from

  11. Four-dimensional coronary morphology and computational hemodynamics

    Science.gov (United States)

    Wahle, Andreas; Mitchell, Steven C.; Ramaswamy, Sharan D.; Chandran, Krishnan B.; Sonka, Milan

    2001-07-01

    Conventional reconstructions from intravascular ultrasound (IVUS) stack the frames as acquired during the pullback of the catheter to form a straight three-dimensional volume, thus neglecting the vessel curvature and merging images from different heart phases. We are developing a comprehensive system for fusion of the IVUS data with the pullback path as determined from x-ray angiography, to create a geometrically accurate 4-D (3-D plus time) model of the coronary vasculature as basis for computational hemodynamics. The overall goal of our work is to correlate shear stress with plaque thickness. The IVUS data are obtained in a single pullback using an automated pullback device; the frames are afterwards assigned to their respective heart phases based upon the ECG signal. A set of 3-D models is reconstructed by fusion of IVUS and angiographic data corresponding to the same ECG-gated heart phase; methods of computational fluid dynamics (CFD) are applied to obtain important hemodynamic data. Combining these models yields the final 4-D reconstruction. Visualization is performed using the platform-independent VRML standard for a user-friendly manipulation of the scene. An extension for virtual angioscopy allows an easy assessment of the vessel features within their local context. Validation was successfully performed both in-vitro and in-vivo.

  12. Improving the Horizontal Transport in the Lower Troposphere with Four Dimensional Data Assimilation

    Science.gov (United States)

    The physical processes involved in air quality modeling are governed by dynamically-generated meteorological model fields. This research focuses on reducing the uncertainty in the horizontal transport in the lower troposphere by improving the four dimensional data assimilation (F...

  13. Construction of a Class of Four-Dimensional Piecewise Affine Systems with Homoclinic Orbits

    Science.gov (United States)

    Wu, Tiantian; Yang, Xiao-Song

    2016-06-01

    Based on mathematical analysis, this paper provides a methodology to ensure the existence of homoclinic orbits in a class of four-dimensional piecewise affine systems. In addition, an example is provided to illustrate the effectiveness of the method.

  14. Assessment of induction of secondary tumours due to various radiotherapy modalities

    International Nuclear Information System (INIS)

    One of the objectives of the European Sixth Framework integrated project MAESTRO is to perform an assessment of risk due to various radiotherapy modalities, regarding secondary tumour induction. Initially, the study will focus on cancer of the prostate and the present work represents the first step towards that goal. One of the intended tools, to be used in the assessment, is the Monte Carlo radiation transport code ORANGE. A validation of the ORANGE code's capability to tally dose on a grid superimposed on an existing MCNP geometry is given. Preliminary results on the dose distribution due to conventional radiotherapy treatment of prostate cancer are discussed. Two mathematical models of the patient are proposed and the clinical relevance of the ADAM phantom is investigated. A problem in comparing average doses provided by commercial treatment planning systems and those calculated with Monte Carlo is noticed. The two proposed models are shown to receive a lower dose and average energy deposition than a 'real' patient. (authors)

  15. Prospective patient-based assessment of effectiveness of palliative radiotherapy for bone metastases

    International Nuclear Information System (INIS)

    Purpose: The primary objective of this report is to prospectively evaluate pain control provided by palliative radiotherapy for all irradiated patients with bone metastases by using their own assessments. Materials and methods: A prospective database was set up for all patients referred for palliative radiotherapy for bone metastases. Patients were asked to rate their pain intensity using an 11 categorical point scale (0=lack of pain, 10=worst pain imaginable). Analgesic consumption during the preceding 24 h was recorded and converted into equivalent total daily dose of oral morphine. For those who received radiotherapy, follow-up was conducted via telephone interviews at week 1, 2, 4, 8 and 12 post treatment using the same pain scale and analgesic diary. Radiotherapy outcome was initially assessed by pain score alone. Complete response (CR) was defined as a pain score of 0. Partial response (PR) was defined as a reduction of score ≥2 or a≥50% reduction of the pre-treatment pain score. We further analyzed outcomes using integrated pain and analgesic scores. Response was defined as either a reduction of pain score ≥2 with at least no increase in analgesics or at least stable pain score with a ≥50% reduction in analgesic intake. Results: One hundred and five patients were treated with palliative radiotherapy. When response evaluation was by pain score alone, the PR rates at 2, 4, 8 and 12 weeks were 44, 42, 30 and 38%, respectively; while the CR rates were 24, 32, 31 and 29%, respectively. The overall response rate at 12 weeks was 67%. When assessed by the integrated pain and analgesic scores, the response rates were 50, 46, 43 and 43%, respectively. Conclusion: The response rate in our patient population is comparable with those reported in clinical trials. This is important when counselling our patients on the expected effectiveness of radiotherapy outside of clinical trials. Our observations confirm the generalizability of the trials conducted to date

  16. Chaotic behaviour of nonlinear coupled reaction–diffusion system in four-dimensional space

    Indian Academy of Sciences (India)

    Li Zhang; Shutang Liu; Chenglong Yu

    2014-06-01

    In recent years, nonlinear coupled reaction–diffusion (CRD) system has been widely investigated by coupled map lattice method. Previously, nonlinear behaviour was observed dynamically when one or two of the three variables in the discrete system change. In this paper, we consider the chaotic behaviour when three variables change, which is called as four-dimensional chaos. When two parameters in the discrete system are unknown, we first give the existing condition of the chaos in four-dimensional space by the generalized definitions of spatial periodic orbits and spatial chaos. In addition, the chaotic behaviour will vary with the parameters. Then we propose a generalized Lyapunov exponent in four-dimensional space to characterize the different effects of parameters on the chaotic behaviour, which has not been studied in detail. In order to verify the chaotic behaviour of the system and the different effects clearly, we simulate the dynamical behaviour in two- and three-dimensional spaces.

  17. Quantitative MR imaging in planning and assessing novel cancer treatments Radiotherapy

    CERN Document Server

    Baustert, I C

    2001-01-01

    Novel treatments in cancer, like conformal radiotherapy and anticancer drugs, require new MRI techniques to assess their benefits and potential. In conformal radiotherapy, MRI can be used to measure the shape and dose of the conformed radiation field in dose sensitive gel test-objects thus validating the predicted dose computed by complex programs. In antiangiogenic drug treatment, the vascular dysfunction of the tumour can be assessed by MRI prior to treatment. Response to treatment may also be monitored by measuring the changes in vascular function. In this thesis, MRI of polyacrylamide gels is investigated as a 3D dosimeter for conformal radiotherapy treatment planning. Quantitative MRI sequences capable of measuring the wide range of T2 values typically expected in gel dosimetry, are identified. Different T2 measurement methods are compared in terms of accuracy, signal to noise ratio and acquisition time. Examples of a complex dose distribution in 2D and 3D are presented and compared to the planned dose p...

  18. Dynamical simulation of neutron-induced fission of uranium isotopes using four-dimensional Langevin equations

    Science.gov (United States)

    Pahlavani, M. R.; Mirfathi, S. M.

    2016-04-01

    Four-dimensional Langevin equations have been suggested for the dynamical simulation of neutron-induced fission at low and medium excitation energies. The mass distribution of the fission fragments, the neutron multiplicity, and the fission cross section for the thermal and fast neutron-induced fission of 233U, 235U, and 238U is studied by considering energy dissipation of the compound nucleus through the fission using four-dimensional Langevin equations combined with a Monte Carlo simulation approach. The calculated results using this approach indicate reasonable agreement with available experimental data.

  19. Prospective assessment of the salivary function by parotid scintigraphy after radiotherapy of 27 nasopharyngeal cancers; evaluation prospective de la fonction salivaire par scintigraphie parotidienne apres radiotherapie de 27 cancers du nasopharynx

    Energy Technology Data Exchange (ETDEWEB)

    Mnejja, W.; Ghorbal, L.; Daoud, J. [Service de radiotherapie oncologique, CHU Habib-Bourguiba, Sfax (Tunisia); Kallel, F.; Guermazi, F. [Service de medecine nucleaire, CHU Habib-Bourguiba, Sfax (Tunisia); Frikha, M. [Service de carcinologie medicale, CHU Habib-Bourguiba, Sfax (Tunisia)

    2011-10-15

    As xerostomia is the main complication after radiotherapy of nasopharyngeal carcinomas, and affects life quality, this study aims at objectively assess the salivary function after radiotherapy of a nasopharyngeal cancer by parotid scintigraphy. 27 seven patients have been treated by radiotherapy with or without chemotherapy. Results are analyzed in terms of salivary toxicity, change of secretion function. No correlation was found between the xerostomia severity and scintigraphy results. Short communication

  20. Four dimensional magnetic resonance imaging with retrospective k-space reordering: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yilin; Yin, Fang-Fang; Cai, Jing, E-mail: jing.cai@duke.edu [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 and Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Chen, Nan-kuei [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 and Brain Imaging and Analysis Center, Duke University Medical Center, Box 2737, Hock Plaza, Durham, North Carolina 27710 (United States); Chu, Mei-Lan [Brain Imaging and Analysis Center, Duke University Medical Center, Box 2737, Hock Plaza, Durham, North Carolina 27710 (United States)

    2015-02-15

    Purpose: Current four dimensional magnetic resonance imaging (4D-MRI) techniques lack sufficient temporal/spatial resolution and consistent tumor contrast. To overcome these limitations, this study presents the development and initial evaluation of a new strategy for 4D-MRI which is based on retrospective k-space reordering. Methods: We simulated a k-space reordered 4D-MRI on a 4D digital extended cardiac-torso (XCAT) human phantom. A 2D echo planar imaging MRI sequence [frame rate (F) = 0.448 Hz; image resolution (R) = 256 × 256; number of k-space segments (N{sub KS}) = 4] with sequential image acquisition mode was assumed for the simulation. Image quality of the simulated “4D-MRI” acquired from the XCAT phantom was qualitatively evaluated, and tumor motion trajectories were compared to input signals. In particular, mean absolute amplitude differences (D) and cross correlation coefficients (CC) were calculated. Furthermore, to evaluate the data sufficient condition for the new 4D-MRI technique, a comprehensive simulation study was performed using 30 cancer patients’ respiratory profiles to study the relationships between data completeness (C{sub p}) and a number of impacting factors: the number of repeated scans (N{sub R}), number of slices (N{sub S}), number of respiratory phase bins (N{sub P}), N{sub KS}, F, R, and initial respiratory phase at image acquisition (P{sub 0}). As a proof-of-concept, we implemented the proposed k-space reordering 4D-MRI technique on a T2-weighted fast spin echo MR sequence and tested it on a healthy volunteer. Results: The simulated 4D-MRI acquired from the XCAT phantom matched closely to the original XCAT images. Tumor motion trajectories measured from the simulated 4D-MRI matched well with input signals (D = 0.83 and 0.83 mm, and CC = 0.998 and 0.992 in superior–inferior and anterior–posterior directions, respectively). The relationship between C{sub p} and N{sub R} was found best represented by an exponential function

  1. A Calogero formulation for four-dimensional black-hole microstates

    Directory of Open Access Journals (Sweden)

    Olaf Lechtenfeld

    2016-02-01

    Full Text Available We extract the leading-order entropy of a four-dimensional extremal black hole in N=2 ungauged supergravity by formulating the CFT1 that is holographically dual to its near-horizon AdS2 geometry, in terms of a rational Calogero model with a known counting formula for the degeneracy of states in its Hilbert space.

  2. Registration-based Reconstruction of Four-dimensional Cone Beam Computed Tomography

    DEFF Research Database (Denmark)

    Christoffersen, Christian; Hansen, David Christoffer; Poulsen, Per Rugaard;

    2013-01-01

    We present a new method for reconstruction of four-dimensional (4D) cone beam computed tomography from an undersampled set of X-ray projections. The novelty of the proposed method lies in utilizing optical flow based registration to facilitate that each temporal phase is reconstructed from the full...

  3. Effect of four-dimensional variational data assimilation in case of nonlinear instability

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of four-dimensional variational data assimilation on the reduction of the forecast errors is investigated for both stable and unstable flows. Numerical results show that the effect is generally positive. Particularly,its effect is much more significant in the presence of nonlinear instability

  4. The Existence of Silnikov's Orbit in Four-dimensional Duffing's Systems

    Institute of Scientific and Technical Information of China (English)

    Wei Li; Peng-cheng Xu

    2003-01-01

    The existence of Silnikov's orbits in a four-dimensional dynamical system is discussed. The existence of Silnikov's orbit resulting in chaotic dynamics is established by the fiber structure of invariant manifold and high-dimensional Melnikov method. Numerical simulations are given to demonstrate the theoretical analysis.

  5. Investigation of a Patient Reported Outcome tool to assess radiotherapy-related toxicity prospectively in patients with lung cancer

    International Nuclear Information System (INIS)

    Background and purpose: There is a paucity of data regarding the feasibility and relevance of Patient Reported Outcome (PRO) tools to assess radiotherapy-related toxicity in lung cancer. Material and methods: From January to June 2013, lung cancer patients undergoing thoracic radiotherapy/chemo-radiotherapy completed nine patient-adapted Common Terminology Criteria for Adverse Events (CTCAE), the European Organisation for Research and Treatment of Cancer Quality of Life (QoL) questionnaire and the Hospital Anxiety and Depression Scale (HADS) at baseline, the end of radiotherapy and at follow-up. Clinicians completed the same CTCAE items and agreement between patients’ and clinicians’ reporting was assessed using weighted kappa coefficients. QoL and HADS scores were correlated with the patients’ and clinicians’ reported toxicity. Results: 70/116 patients completed the questionnaires for at least one time point excluding baseline. Agreement between patients’ and clinicians’ reported toxicity ranged from slight to substantial. Most discrepancies were within one grade and patients reported greater severity than clinicians for most symptoms. QoL and HADS scores were more strongly correlated with the patients’ compared to clinicians’ matching toxicity reports. The PRO tool was found to be statistically reliable. Conclusions: The use of a PRO tool in lung cancer radiotherapy is feasible, reliable and acceptable to patients. PROs should be integrated in future clinical trials evaluating new radiotherapy approaches to assess toxicity

  6. Four-dimensional optical coherence tomography imaging of total liquid ventilated rats

    Science.gov (United States)

    Kirsten, Lars; Schnabel, Christian; Gaertner, Maria; Koch, Edmund

    2013-06-01

    Optical coherence tomography (OCT) can be utilized for the spatially and temporally resolved visualization of alveolar tissue and its dynamics in rodent models, which allows the investigation of lung dynamics on the microscopic scale of single alveoli. The findings could provide experimental input data for numerical simulations of lung tissue mechanics and could support the development of protective ventilation strategies. Real four-dimensional OCT imaging permits the acquisition of several OCT stacks within one single ventilation cycle. Thus, the entire four-dimensional information is directly obtained. Compared to conventional virtual four-dimensional OCT imaging, where the image acquisition is extended over many ventilation cycles and is triggered on pressure levels, real four-dimensional OCT is less vulnerable against motion artifacts and non-reproducible movement of the lung tissue over subsequent ventilation cycles, which widely reduces image artifacts. However, OCT imaging of alveolar tissue is affected by refraction and total internal reflection at air-tissue interfaces. Thus, only the first alveolar layer beneath the pleura is visible. To circumvent this effect, total liquid ventilation can be carried out to match the refractive indices of lung tissue and the breathing medium, which improves the visibility of the alveolar structure, the image quality and the penetration depth and provides the real structure of the alveolar tissue. In this study, a combination of four-dimensional OCT imaging with total liquid ventilation allowed the visualization of the alveolar structure in rat lung tissue benefiting from the improved depth range beneath the pleura and from the high spatial and temporal resolution.

  7. A symplectic rearrangement of the four dimensional non-geometric scalar potential

    CERN Document Server

    Shukla, Pramod

    2015-01-01

    We present a symplectic rearrangement of the effective four-dimensional non-geometric scalar potential resulting from the type IIB superstring compactification on Calabi Yau orientifolds. The strategy has two main steps. In the first step, we rewrite the four dimensional scalar potential utilizing some interesting flux combinations which we call {\\it new generalized flux orbits}. After invoking a couple of non-trivial symplectic relations, in the second step, we further rearrange all the pieces of scalar potential into a completely `symplectic-formulation' which involves only the symplectic ingredients (such as period matrix etc.) without the need of knowing Calabi Yau metric. Moreover, the scalar potential under consideration is induced by a generic tree level K\\"{a}hler potential and (non-geometric) flux superpotential for arbitrary numbers of complex structure moduli, K\\"ahler moduli and odd-axions. Finally, we exemplify our symplectic formulation for the two well known toroidal examples based on type IIB ...

  8. Novel four-dimensional autonomous chaotic system generating one-, two-, three- and four-wing attractors

    International Nuclear Information System (INIS)

    In this paper, we propose a novel four-dimensional autonomous chaotic system. Of particular interest is that this novel system can generate one-, two, three- and four-wing chaotic attractors with the variation of a single parameter, and the multi-wing type of the chaotic attractors can be displayed in all directions. The system is simple with a large positive Lyapunov exponent and can exhibit some interesting and complicated dynamical behaviours. Basic dynamical properties of the four-dimensional chaotic system, such as equilibrium points, the Poincaré map, the bifurcation diagram and the Lyapunov exponents are investigated by using either theoretical analysis or numerical method. Finally, a circuit is designed for the implementation of the multi-wing chaotic attractors. The electronic workbench observations are in good agreement with the numerical simulation results. (general)

  9. Three- and four-dimensional ultrasound in fetal echocardiography: an up-to-date overview.

    Science.gov (United States)

    Adriaanse, B M E; van Vugt, J M G; Haak, M C

    2016-09-01

    Congenital heart diseases (CHD) are the most commonly overlooked lesions in prenatal screening programs. Real-time two-dimensional ultrasound (2DUS) is the conventionally used tool for fetal echocardiography. Although continuous improvements in the hardware and post-processing software have resulted in a good image quality even in late first trimester, 2DUS still has its limitations. Four-dimensional ultrasound with spatiotemporal image correlation (STIC) is an automated volume acquisition, recording a single three-dimensional (3D) volume throughout a complete cardiac cycle, which results in a four-dimensional (4D) volume. STIC has the potential to increase the detection rate of CHD. The aim of this study is to provide a practical overview of the possibilities and (dis)advantages of STIC. A review of literature and evaluation of the current status and clinical value of 3D/4D ultrasound in prenatal screening and diagnosis of congenital heart disease are presented. PMID:26963426

  10. Three- and four-dimensional ultrasound in fetal echocardiography: an up-to-date overview.

    Science.gov (United States)

    Adriaanse, B M E; van Vugt, J M G; Haak, M C

    2016-09-01

    Congenital heart diseases (CHD) are the most commonly overlooked lesions in prenatal screening programs. Real-time two-dimensional ultrasound (2DUS) is the conventionally used tool for fetal echocardiography. Although continuous improvements in the hardware and post-processing software have resulted in a good image quality even in late first trimester, 2DUS still has its limitations. Four-dimensional ultrasound with spatiotemporal image correlation (STIC) is an automated volume acquisition, recording a single three-dimensional (3D) volume throughout a complete cardiac cycle, which results in a four-dimensional (4D) volume. STIC has the potential to increase the detection rate of CHD. The aim of this study is to provide a practical overview of the possibilities and (dis)advantages of STIC. A review of literature and evaluation of the current status and clinical value of 3D/4D ultrasound in prenatal screening and diagnosis of congenital heart disease are presented.

  11. The four-dimensional mouse whole-body phantoms and its application in medical imaging research

    International Nuclear Information System (INIS)

    Medical imaging simulation is a powerful tool for characterizing,evaluating,and optimizing medical imaging devices and techniques. A vital aspect of simulation is to have a realistic phantom or model of the subject's anatomy. Four-dimensional mouse whole-body phantoms provide realistic models of the mouse anatomy and physiology for imaging studies. When combined with accurate models for the imaging process,are capable of providing a wealth of realistic imaging data from subjects with various anatomies and motions (cardiac and respiratory) in health and disease. With this ability, the four-dimensional mouse whole-body phantoms have enormous potential to study the effects of anatomical, physiological and physical factors on medical and small animal imaging and to research new instrumentation, image acquisition strategies, image processing, reconstruction methods, image visualization and interpretation techniques. (authors)

  12. Non-Abelian Gauge Field Localized on Walls with Four-Dimensional World Volume

    CERN Document Server

    Ohta, Kazutoshi

    2010-01-01

    A mechanism using the position-dependent gauge coupling is proposed to localize non-Abelian gauge fields on domain walls in five-dimensional space-time. Low-energy effective theory posseses a massless vector field, and a mass gap. The four-dimensional gauge invariance is maintained intact. We obtain perturbatively the four-dimensional Coulomb law for static sources on the domain wall. BPS domain wall solutions with the localization mechanism are explicitly constructed in the U(1)xU(1) supersymmetric gauge theory coupling to the non-Abelian gauge fields only through the cubic prepotential, which is consistent with the general principle of supersymmetry in five-dimensional space-time.

  13. Four-dimensional SAR Imaging Algorithm Based on Iterative Reconstruction of Magnitude and Phase

    OpenAIRE

    Ren Xiaozhen; Yang Ruliang

    2016-01-01

    Observation data obtained from the Four-Dimensional (4D) Synthetic Aperture Radar (SAR) system is sparse and non-uniform in the baseline-time plane. Hence, the imaging results acquired by traditional Fourier-based methods are limited by high side lobes. Compressive Sensing (CS) is a recently proposed technique that allows for the recovery of an unknown sparse signal with overwhelming probability from very limited samples. However, the standard CS framework has been developed for real-valued s...

  14. Statistical Entropy of Nonextremal Four-Dimensional Black Holes and U-Duality

    International Nuclear Information System (INIS)

    We identify the states in string theory which are responsible for the entropy of near-extremal rotating four-dimensional black holes in N=8 supergravity. For black holes far from extremality (with no rotation), the Bekenstein-Hawking entropy is exactly matched by a mysterious duality invariant extension of the formulas derived for near-extremal black holes states. copyright 1996 The American Physical Society

  15. Morphogenesis of an extended phenotype: four-dimensional ant nest architecture

    OpenAIRE

    Minter, Nicholas J.; Franks, Nigel R.; Robson Brown, Katharine A.

    2011-01-01

    Animals produce a variety of structures to modify their environments adaptively. Such structures represent extended phenotypes whose development is rarely studied. To begin to rectify this, we used micro-computed tomography (CT) scanning and time-series experiments to obtain the first high-resolution dataset on the four-dimensional growth of ant nests. We show that extrinsic features within the environment, such as the presence of planes between layers of sediment, influence the architecture ...

  16. Iterative sorting for four-dimensional CT images based on internal anatomy motion

    OpenAIRE

    Zeng, Rongping; Fessler, Jeffrey A.; Balter, James M.; Balter, Peter A.

    2008-01-01

    Current four-dimensional (4D) computed tomography (CT) imaging techniques using multi-slice CT scanners require retrospective sorting of the reconstructed two-dimensional (2D) CT images. Most existing sorting methods depend on externally monitored breathing signals recorded by extra instruments. External signals may not always accurately capture the breathing status and may lead to severe discontinuity artifacts in the sorted CT volumes. This paper describes a method to find the temporal corr...

  17. A New Class of Four-Dimensional N=1 Supergravity with Non-minimal Derivative Couplings

    CERN Document Server

    Farakos, Fotis; Kehagias, Alex; Saridakis, Emmanuel N

    2012-01-01

    In the N=1 four-dimensional new-minimal supergravity framework, we supersymmetrise the coupling of the scalar kinetic term to the Einstein tensor. This coupling, although introduces a non-minimal derivative interaction of curvature to matter, it does not introduce harmful higher-derivatives. For this construction, we employ off-shell chiral and real linear multiplets. Physical scalars are accommodated in the chiral multiplet whereas curvature resides in a linear one.

  18. Solutions of the generalized Weierstrass representation in four-dimensional Euclidean space

    OpenAIRE

    P. Bracken; Grundland, A. M.

    2003-01-01

    Several classes of solutions of the generalized Weierstrass system, which induces constant mean curvature surfaces into four-dimensional Euclidean space are constructed. A gauge transformation allows us to simplify the system considered and derive factorized classes of solutions. A reduction of the generalized Weierstrass system to decoupled CP^1 sigma models is also considered. A new procedure for constructing certain classes of solutions, including elementary solutions (kinks and bumps) and...

  19. On the blow-up of four dimensional Ricci flow singularities

    CERN Document Server

    Máximo, Davi

    2012-01-01

    In this paper we prove a conjecture by Feldman-Ilmanen-Knopf in \\cite{FIK} that the gradient shrinking soliton metric they constructed on the tautological line bundle over $\\CP^1$ is the uniform limit of blow-ups of a type I Ricci flow singularity on a closed manifold. We use this result to show that limits of blow-ups of Ricci flow singularities on closed four dimensional manifolds do not necessarily have non-negative Ricci curvature.

  20. Non-diagonal four-dimensional cohomogeneity-one Einstein metrics in various signatures

    CERN Document Server

    Dunajski, Maciej

    2016-01-01

    Most known four-dimensional cohomogeneity-one Einstein metrics are diagonal in the basis defined by the left-invariant one-forms, though some essentially non-diagonal ones are known. We consider the problem of explicitly seeking non-diagonal Einstein metrics, and we find solutions which in some cases exhaust the possibilities. In particular we construct new examples of neutral signature non--diagonal Bianchi type VIII Einstein metrics with self--dual Weyl tensor.

  1. The Radiobiological Basis for Improvements in Radiotherapy and Low Dose Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hei, Tom K

    2009-12-09

    Overall Goal: This conference grant was proposed to organize and host an international conference at Columbia University in New York to critically assess the cellular and molecular signaling events and tissue response following radiation damage. The conference would also serve as a venue to play tribute to the more than forty years contributions made by Professor Eric J. Hall to the radiation biology field. The goals of the meeting were to examine tumor hypoxia and sensitizer development; recent advances made in clinical radiotherapy; addressed several low dose phenomena, including genomic instability and bystander effects that are important in radiation risk assessment. Study and Results: The symposium was held on October 13th and 14th, 2008 at the Alfred Lerner Hall in the Morningside campus of Columbia University. The symposium, entitled “From Beans to Genes: A Forty Year Odyssey in Radiation Biology” was attended by more than 120 faculty, scientists, clinicians, fellows and students. The symposium, spanned over a day and a half, covered four scientific themes. These included tumor hypoxia and radiosensitizers; low dose radiation response; radiation biology in the practice of radiotherapy, and radiation hazard in space and genetic predisposition to cancer. The program of the symposium is as follow:

  2. Assessment of factors connected with radiotherapy influencing the cosmetic effect in breast conserving therapy

    International Nuclear Information System (INIS)

    Aim: To compare cosmetic results of different radiotherapy schedules used in the treatment of breast cancer after breast radiotherapy and to identify factors affecting cosmetic outcomes. Material and methods: Ninety-four patients irradiated. Median follow-up of 29 months (range 18-154 mo.). Patients were treated with standard fractionation 45-50 Gy/20-25 fx/4-5 weeks. Boost up to 10 Gy. Late effects were evaluated using the LENT-SOMA scoring scale. The cosmetic results were assessed on a four-point scale and presence of concomitant chemotherapy. Results: LENT-SOMA grade 3 toxicity was observed only in 8 (8,5%) patients. The factor associated with hyperpigmentation is large breast size. The significant risk factors for teleangiectasia are high dose and use photon energy 1,33 MeV beam. Factors found to impact significantly cosmetics adversely fibrosis was large breast size. Breast fibrosis were more frequent observed in woman after whole dose 50 Gy. There were no differences in breast skin thick between analysed factors. Conclusions: After irradiating large breasts more often than one observes the fibrosis of the breast in the case of small and average breasts and discolour of the skin. Irradiating photons from the cobalt source in the comparison with photons about higher energy at women with large breasts, there is the reason more frequent occurrence of the skin angioma. For the final cosmetic effect of radiotherapy in saving treatment, they do not have the impact: tumor size, boost method, chemical treatment, patients age. (authors)

  3. Assessment of improved organ at risk sparing for advanced cervix carcinoma utilizing precision radiotherapy techniques

    Energy Technology Data Exchange (ETDEWEB)

    Georg, D.; Georg, P.; Hillbrand, M.; Poetter, R.; Mock, U. [Dept. of Radiotherapy, Medical Univ. AKH, Vienna (Austria)

    2008-11-15

    Purpose: to evaluate the potential benefit of proton therapy and photon based intensity-modulated radiotherapy in comparison to 3-D conformal photon radiotherapy (3D-CRT) in locally advanced cervix cancer. Patients and methods: in five patients with advanced cervix cancer 3D-CRT (four-field box) was compared with intensity modulated photon (IMXT) and proton therapy (IMPT) as well as proton beam therapy (PT) based on passive scattering. Planning target volumes (PTVs) included primary tumor and pelvic and para-aortic lymph nodes. Dose-volume histograms (DVHs) were analyzed for the PTV and various organs at risk (OARs) (rectal wall, bladder, small bowel, colon, femoral heads, and kidneys). In addition dose conformity, dose inhomogeneity and overall volumes of 50% isodoses were assessed. Results: all plans were comparable concerning PTV parameters. Large differences between photon and proton techniques were seen in volumes of the 50% isodoses and conformity indices. DVH for colon and small bowel were significantly improved with PT and IMPT compared to IMXT, with D{sub mean} reductions of 50-80%. Doses to kidneys and femoral heads could also be substantially reduced with PT and IMPT. Sparing of rectum and bladder was superior with protons as well but less pronounced. Conclusion: proton beam RT has significant potential to improve treatment related side effects in the bowel compared to photon beam RT in patients with advanced cervix carcinoma. (orig.)

  4. Reliability of Quantitative Ultrasonic Assessment of Normal-Tissue Toxicity in Breast Cancer Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: We have recently reported that ultrasound imaging, together with ultrasound tissue characterization (UTC), can provide quantitative assessment of radiation-induced normal-tissue toxicity. This study’s purpose is to evaluate the reliability of our quantitative ultrasound technology in assessing acute and late normal-tissue toxicity in breast cancer radiotherapy. Method and Materials: Our ultrasound technique analyzes radiofrequency echo signals and provides quantitative measures of dermal, hypodermal, and glandular tissue toxicities. To facilitate easy clinical implementation, we further refined this technique by developing a semiautomatic ultrasound-based toxicity assessment tool (UBTAT). Seventy-two ultrasound studies of 26 patients (720 images) were analyzed. Images of 8 patients were evaluated for acute toxicity (<6 months postradiotherapy) and those of 18 patients were evaluated for late toxicity (≥6 months postradiotherapy). All patients were treated according to a standard radiotherapy protocol. To assess intraobserver reliability, one observer analyzed 720 images in UBTAT and then repeated the analysis 3 months later. To assess interobserver reliability, three observers (two radiation oncologists and one ultrasound expert) each analyzed 720 images in UBTAT. An intraclass correlation coefficient (ICC) was used to evaluate intra- and interobserver reliability. Ultrasound assessment and clinical evaluation were also compared. Results: Intraobserver ICC was 0.89 for dermal toxicity, 0.74 for hypodermal toxicity, and 0.96 for glandular tissue toxicity. Interobserver ICC was 0.78 for dermal toxicity, 0.74 for hypodermal toxicity, and 0.94 for glandular tissue toxicity. Statistical analysis found significant changes in dermal (p < 0.0001), hypodermal (p = 0.0027), and glandular tissue (p < 0.0001) assessments in the acute toxicity group. Ultrasound measurements correlated with clinical Radiation Therapy Oncology Group (RTOG) toxicity scores of patients

  5. Chiral four-dimensional F-theory compactifications with SU(5) and multiple U(1)-factors

    OpenAIRE

    Mirjam Cvetič; Antonella Grassi; Denis Klevers; Hernan Piragua

    2014-01-01

    We develop geometric techniques to determine the spectrum and the chiral indices of matter multiplets for four-dimensional F-theory compactifications on elliptic Calabi-Yau fourfolds with rank two Mordell-Weil group. The general elliptic fiber is the Calabi-Yau onefold in dP 2 . We classify its resolved elliptic fibrations over a general base B . The study of singularities of these fibrations leads to explicit matter representations, that we determine both for U(1) × U(1) and SU(5) × U(1) × U...

  6. Supergravity Backgrounds for Four-Dimensional Maximally Supersymmetric Yang-Mills

    CERN Document Server

    Maxfield, Travis

    2016-01-01

    In this note, we describe supersymmetric backgrounds for the four-dimensional maximally supersymmetric Yang-Mills theory. As an extension of the method of Festuccia and Seiberg to sixteen supercharges in four dimensions, we utilize the coupling of the gauge theory to maximally extended conformal supergravity. Included among the fields of the conformal supergravity multiplet is the complexified coupling parameter of the gauge theory; therefore, backgrounds with spacetime varying coupling--such as appear in F-theory and Janus configurations--are naturally included in this formalism. We demonstrate this with a few examples from past literature.

  7. Four-Dimensional Effective Supergravity and Soft Terms in M-Theory

    OpenAIRE

    Choi, Kiwoon; Kim, Hang Bae; Munoz, Carlos

    1997-01-01

    We provide a simple macroscopic analysis of the four-dimensional effective supergravity of the Ho\\v{r}ava-Witten M-theory which is expanded in powers of $\\kappa^{2/3}/\\rho V^{1/3}$ and $\\kappa^{2/3}\\rho/V^{2/3}$ where $\\kappa^2$, $V$ and $\\rho$ denote the eleven-dimensional gravitational coupling, the Calabi-Yau volume and the eleventh length respectively. Possible higher order terms in the K\\"ahler potential are identified and matched with the heterotic string corrections. In the context of ...

  8. The dissociative adsorption of hydrogen: Two-, three-, and four-dimensional quantum simulations

    DEFF Research Database (Denmark)

    Nielsen, Ulrik; Halstead, David; Holloway, Stephen;

    1990-01-01

    A quantum wave packet calculation for the activated dissociative adsorption of H2 is presented. Restricting the motion of the molecule to lie within a plane normal to the surface we have treated all four molecular degrees of freedom exactly. We compare results obtained using two-, three-, and four......-dimensional simulations on the same potential and show that by restricting the molecular orientation, important dynamical effects are lost. The potential employed in the calculations has been obtained using the effective medium approximation. In the simulations it has been possible to treat dissociation, rotations...

  9. Four-dimensional (4D) tracking of high-temperature microparticles

    Science.gov (United States)

    Wang, Zhehui; Liu, Q.; Waganaar, W.; Fontanese, J.; James, D.; Munsat, T.

    2016-11-01

    High-speed tracking of hot and molten microparticles in motion provides rich information about burning plasmas in magnetic fusion. An exploding-wire apparatus is used to produce moving high-temperature metallic microparticles and to develop four-dimensional (4D) or time-resolved 3D particle tracking techniques. The pinhole camera model and algorithms developed for computer vision are used for scene calibration and 4D reconstructions. 3D positions and velocities are then derived for different microparticles. Velocity resolution approaches 0.1 m/s by using the local constant velocity approximation.

  10. Quasinormal modes of four-dimensional topological nonlinear charged Lifshitz black holes

    Energy Technology Data Exchange (ETDEWEB)

    Becar, Ramon [Universidad Cato lica de Temuco, Departamento de Ciencias Matematicas y Fisicas, Temuco (Chile); Gonzalez, P.A. [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)

    2016-02-15

    We study scalar perturbations of four- dimensional topological nonlinear charged Lifshitz black holes with spherical and plane transverse sections, and we find numerically the quasinormal modes for scalar fields. Then we study the stability of these black holes under massive and massless scalar field perturbations. We focus our study on the dependence of the dynamical exponent, the nonlinear exponent, the angular momentum, and the mass of the scalar field in the modes. It is found that the modes are overdamped, depending strongly on the dynamical exponent and the angular momentum of the scalar field for a spherical transverse section. In contrast, for plane transverse sections the modes are always overdamped. (orig.)

  11. The pedagogical value of the four-dimensional picture: I. Relativistic mechanics of point particles

    International Nuclear Information System (INIS)

    In this paper we outline two subjects of relativistic mechanics: (i) the set of allowable world lines, and (ii) the origin of the relativistic law of dynamics governing point particles. We show that: (i) allowable world lines in the classical theory of particles and fields are quite simple geometric objects as opposed to their associated three-dimensional trajectories; and (ii) Newton’s second law requires neither modification nor generalization, it should only be smoothly embedded in the four-dimensional geometry of Minkowski spacetime to yield the dynamical law for relativistic particles. (paper)

  12. Bifurcation structures and transient chaos in a four-dimensional Chua model

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, Anderson, E-mail: hoffande@gmail.com; Silva, Denilson T. da; Manchein, Cesar, E-mail: cesar.manchein@udesc.br; Albuquerque, Holokx A., E-mail: holokx.albuquerque@udesc.br

    2014-01-10

    A four-dimensional four-parameter Chua model with cubic nonlinearity is studied applying numerical continuation and numerical solutions methods. Regarding numerical solution methods, its dynamics is characterized on Lyapunov and isoperiodic diagrams and regarding numerical continuation method, the bifurcation curves are obtained. Combining both methods the bifurcation structures of the model were obtained with the possibility to describe the shrimp-shaped domains and their endoskeletons. We study the effect of a parameter that controls the dimension of the system leading the model to present transient chaos with its corresponding basin of attraction being riddled.

  13. A Note On The Semiclassical Formulation Of BPS States In Four-Dimensional N=2 Theories

    CERN Document Server

    Brennan, T Daniel

    2016-01-01

    Vector spaces of (framed) BPS states of Lagrangian four-dimensional N=2 field theories can be defined in semiclassical chambers in terms of the $L^2$-cohomology of Dirac-like operators on monopole moduli spaces. This was spelled out previously for theories with only vectormultiplets, taking into account only a subset of the possible half-supersymmetric 't Hooft-Wilson line defects. This note completes the discussion by describing the modifications needed when including matter hypermultiplets together with arbitrary 't Hooft-Wilson line defects. Two applications of this extended discussion are given.

  14. Quality of life assessment with different radiotherapy schedules in palliative management of advanced carcinoma esophagus: A prospective randomized study

    Directory of Open Access Journals (Sweden)

    Shaveta Mehta

    2008-01-01

    Full Text Available Aim: To investigate the quality of life (QOL of patients with advanced carcinoma esophagus treated with different palliative radiation schedules. Methods: Sixty-two consecutive patients with inoperable, non-metastatic carcinoma of the esophagus were randomly allocated to Arm-A (external radiotherapy 30 Gy/10 fractions + brachytherapy 12 Gy/two sessions, Arm-B (external radiotherapy 30 Gy /10 fractions and Arm-C (external radiotherapy 20Gy /five fractions. The QOL was assessed using the European Organization for Research and Treatment of Cancer questionnaire at presentation, after treatment and at 3 months follow-up. Results: The mean QOL score improved, in arm-A from 38 to 52 after treatment and 56 at 3 months, in arm-B from 30 to 44 after treatment and 55 at 3 months and in arm-C from 24 to 40 after treatment but decreased to 37 at 3 months. Improvement in dysphagia scores at the first follow-up was 46.1% in arm-A, 25.0% in arm-B and 22.6% in arm-C. The difference was maintained at 3 months, with maximum improvement in arm-A (57.6%. No significant differences were found between the three arms with regard to complications and additional procedures needed for relief of dysphagia. Conclusion: In comparison with external radiotherapy alone, external radiotherapy with intraluminal brachytherapy has shown a trend toward better QOL and consistent dysphagia relief without significant difference in adverse effects.

  15. Quality assessment for VMAT prostate radiotherapy planning based on data envelopment analysis

    International Nuclear Information System (INIS)

    The majority of commercial radiotherapy treatment planning systems requires planners to iteratively adjust the plan parameters in order to find a satisfactory plan. This iterative trial-and-error nature of radiotherapy treatment planning results in an inefficient planning process and in order to reduce such inefficiency, plans can be accepted without achieving the best attainable quality. We propose a quality assessment method based on data envelopment analysis (DEA) to address this inefficiency. This method compares a plan of interest to a set of past delivered plans and searches for evidence of potential further improvement. With the assistance of DEA, planners will be able to make informed decisions on whether further planning is required and ensure that a plan is only accepted when the plan quality is close to the best attainable one. We apply the DEA method to 37 prostate plans using two assessment parameters: rectal generalized equivalent uniform dose (gEUD) as the input and D95 (the minimum dose that is received by 95% volume of a structure) of the planning target volume (PTV) as the output. The percentage volume of rectum overlapping PTV is used to account for anatomical variations between patients and is included in the model as a non-discretionary output variable. Five plans that are considered of lesser quality by DEA are re-optimized with the goal to further improve rectal sparing. After re-optimization, all five plans improve in rectal gEUD without clinically considerable deterioration of the PTV D95 value. For the five re-optimized plans, the rectal gEUD is reduced by an average of 1.84 Gray (Gy) with only an average reduction of 0.07 Gy in PTV D95. The results demonstrate that DEA can correctly identify plans with potential improvements in terms of the chosen input and outputs. (paper)

  16. A novel four-dimensional analytical approach for analysis of complex samples.

    Science.gov (United States)

    Stephan, Susanne; Jakob, Cornelia; Hippler, Jörg; Schmitz, Oliver J

    2016-05-01

    A two-dimensional LC (2D-LC) method, based on the work of Erni and Frei in 1978, was developed and coupled to an ion mobility-high-resolution mass spectrometer (IM-MS), which enabled the separation of complex samples in four dimensions (2D-LC, ion mobility spectrometry (IMS), and mass spectrometry (MS)). This approach works as a continuous multiheart-cutting LC system, using a long modulation time of 4 min, which allows the complete transfer of most of the first - dimension peaks to the second - dimension column without fractionation, in comparison to comprehensive two-dimensional liquid chromatography. Hence, each compound delivers only one peak in the second dimension, which simplifies the data handling even when ion mobility spectrometry as a third and mass spectrometry as a fourth dimension are introduced. The analysis of a plant extract from Ginkgo biloba shows the separation power of this four-dimensional separation method with a calculated total peak capacity of more than 8700. Furthermore, the advantage of ion mobility for characterizing unknown compounds by their collision cross section (CCS) and accurate mass in a non-target approach is shown for different matrices like plant extracts and coffee. Graphical abstract Principle of the four-dimensional separation. PMID:27038056

  17. An introduction to an alternative four-dimensional formalism of the special theory of relativity

    International Nuclear Information System (INIS)

    A formulation of the four-dimensional vector laws of physics which emphasizes the transformation of position and time using the four-vectors (R', 0) and (0, ct') is presented. One goal of the formalism is to incorporate the Lorentz co-ordinate transformation of measured position and time intervals. Another goal is to generate vector laws of physics in both three- and four-dimensional formats. A definition of the electrostatic field is introduced which can be inserted into a four-vector allowing Gauss' law to be interpreted as both covariant and numerically invariant. Consistent with the definition of the electrostatic field are revised definitions of force, magnetic field, charge density and current. The alternative formulation of standard theory suggests that the concept of geometric invariance was neglected in deriving the three-dimensional vector laws of physics. The Minkowski formulation and the alternative formulation together illustrate two basic ways of transforming length and time intervals in the special theory of relativity

  18. Four-dimensional conversion for spiritual leadership development: A missiological approach for African churches

    Directory of Open Access Journals (Sweden)

    Kalemba Mwambazambi

    2014-04-01

    Full Text Available The process of a four-dimensional conversion and/or transformation strives in helping the leadership of an organisation, especially such as the church, with practical ways that may lead to the development of an effective leadership by observing the four important aspects of human spirituality as elaborated on in the article. The spiritual, intellectual, moral and socio-political dimensions of the transformation can be catered for so that the complete inner being of humans, as well as their social and political attitudes and behaviours, can equally be transformed to maximum spiritual, personal and socio-political profitability. Mutombo-Mukendi demonstrates that the need for a spiritual leadership that can contribute to an effective transformation of Africa is dire, both for the church and the larger community. The real challenge is how to develop such leadership. This article provides intentional and practical ways that may lead to the development of the needed leadership. Four-dimensional transformation of people can be planned and carried out both in the church arena and in the surrounding communities. Skills development and transfer can also take place when skilled people from the church work with unskilled people from the community.

  19. Randomized Clinical Trial to Assess the Efficacy of Radiotherapy in Primary Mediastinal Large B-Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Aviles, Agustin, E-mail: agustin.aviles@imss.gob.mx [Oncology Research Unit, Oncology Hospital, National Medical Center, IMSS, Mexico, D. F. (Mexico); Neri, Natividad [Department of Hematology, Oncology Hospital, National Medical Center, IMSS, Mexico, D. F. (Mexico); Fernandez, Raul [Department of Radiation Therapy, Oncology Hospital, National Medical Center, IMSS, Mexico, D. F. (Mexico); Huerta-Guzman, Judith; Nambo, Maria J. [Department of Hematology, Oncology Hospital, National Medical Center, IMSS, Mexico, D. F. (Mexico)

    2012-07-15

    Purpose: We developed a controlled clinical trial to assess the efficacy and toxicity of adjuvant-involved field radiotherapy (IFRT) in patients with primary mediastinal B-cell lymphoma that achieved complete response after the patients were treated with cyclophosphamide, doxorubicin, vincristine, prednisone, and rituximab (R-CHOP-14). Methods and Materials: Between January 2001 and June 2004, 124 consecutive patients who were in complete remission after dose dense chemotherapy and rituximab administration (R-CHOP14) were randomly assigned to received IFRT (30 Gy). Sixty-three patients received IFR, and 61 patients did not (control group). Results: The study aimed to include 182 patients in each arm but was closed prematurely because in a security analysis (June 2004), progression and early relapse were more frequent in patients that did not received IFRT. Patients were followed until March 2009, at which point actuarial curves at 10 years showed that progression free-survival was 72% in patients who received IFR and 20% in the control group (p < 0.001), overall survival was 72% and 31%, respectively (p < 0.001). Acute toxicity was mild and well tolerated. Discussion: Adjuvant radiotherapy to sites of bulky disease was the only difference to have an improvement in outcome in our patients; the use of rituximab during induction did not improve complete response rates and did affect overall survival; patients who received rituximab but not IFRT had a worse prognosis. Conclusions: The use of IFRT in patients with primary mediastinal B-cell lymphoma who achieved complete response remain as the best treatment available, even in patients that received rituximab during induction.

  20. On the existence of bifocal heteroclinic cycles in a class of four-dimensional piecewise affine systems

    Science.gov (United States)

    Wu, Tiantian; Yang, Xiao-Song

    2016-05-01

    Based on mathematical analysis, this paper provides a methodology to ensure the existence of heteroclinic cycles in a class of four-dimensional piecewise affine systems. In addition, examples are provided to illustrate the effectiveness of the method.

  1. Fluctuation in measurements of pulmonary nodule under tidal volume ventilation on four-dimensional computed tomography: preliminary results

    International Nuclear Information System (INIS)

    The present study aimed to assess the feasibility of four-dimensional (4D) chest computed tomography (CT) under tidal volume ventilation and the impact of respiratory motion on quantitative analysis of CT measurements. Forty-four pulmonary nodules in patients with metastatic disease were evaluated. CT examinations were performed using a 256 multidetector-row CT (MDCT) unit. Volume data were obtained from the lower lung fields (128 mm) above the diaphragm during dynamic CT acquisition. The CT parameters used were 120 kV, 100 or 150 mA, 0.5 s-1, and 0.5 mm collimation. Image data were reconstructed every 0.1 s during one respiratory cycle by a 180 reconstruction algorithm for four independent fractions of the respiratory cycle. Pulmonary nodules were measured along their longest and shortest axes using electronic calipers. Automated volumetry was assessed using commercially available software. The diameters of long and short axes in each frame were 9.0-9.6 mm and 7.1-7.5 mm, respectively. There was fluctuation of the long axis diameters in the third fraction. The mean volume in each fraction ranged from 365 to 394 mm3. Statistically significant fluctuation was also found in the third fraction. 4D-CT under tidal volume ventilation is feasible to determine diameter or volume of the pulmonary nodule. (orig.)

  2. Structures of larger proteins in solution: Three- and four-dimensional heteronuclear NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gronenborn, A.M.; Clore, G.M. [National Institutes of Health, Bethesda, MD (United States)

    1994-12-01

    Complete understanding of a protein`s function and mechanism of action can only be achieved with a knowledge of its three-dimensional structure at atomic resolution. At present, there are two methods available for determining such structures. The first method, which has been established for many years, is x-ray diffraction of protein single crystals. The second method has blossomed only in the last 5 years and is based on the application of nuclear magnetic resonance (NMR) spectroscopy to proteins in solution. This review paper describes three- and four-dimensional NMR methods applied to protein structure determination and was adapted from Clore and Gronenborn. The review focuses on the underlying principals and practice of multidimensional NMR and the structural information obtained.

  3. Metallic phase of the quantum Hall effect in four-dimensional space

    Science.gov (United States)

    Edge, Jonathan; Tworzydlo, Jakub; Beenakker, Carlo

    2013-03-01

    We study the phase diagram of the quantum Hall effect in four-dimensional (4D) space. Unlike in 2D, in 4D there exists a metallic as well as an insulating phase, depending on the disorder strength. The critical exponent ν ~ 1 . 2 of the diverging localization length at the quantum Hall insulator-to-metal transition differs from the semiclassical value ν = 1 of 4D Anderson transitions in the presence of time-reversal symmetry. Our numerical analysis is based on a mapping of the 4D Hamiltonian onto a 1D dynamical system, providing a route towards the experimental realization of the 4D quantum Hall effect. NanoCTM, FOM/NWO, ERC

  4. Flame four-dimensional deflection tomography with compressed-sensing-revision reconstruction

    Science.gov (United States)

    Zhang, Bin; Zhao, Minmin; Liu, Zhigang; Wu, Zhaohang

    2016-08-01

    Deflection tomography with limited angle projections was investigated to visualize a premixed flame. A projection sampling system for deflection tomography was used to obtain chronological deflectogram arrays at six view angles with only a pair of gratings. A new iterative reconstruction algorithm with deflection angle compressed-sensing revision was developed to improve reconstruction-distribution quality from incomplete projection data. Numerical simulation and error analysis provided a good indication of algorithm precision and convergence. In the experiment, 150 fringes were processed, and temperature distributions in 20 cross-sections were reconstructed from projection data in four instants. Four-dimensional flame structures and temperature distributions in the flame interior were visualized using the visualization toolkit. The experimental reconstruction was then compared with the result obtained from computational fluid dynamic analysis.

  5. On the existence of rigid spheres in four-dimensional spacetime manifolds

    CERN Document Server

    Gittel, Hans-Peter; Kijowski, Jerzy

    2015-01-01

    This paper deals with the generalization of usual round spheres in the flat Minkowski spacetime to the case of a generic four-dimensional spacetime manifold $M$. We consider geometric properties of sphere-like submanifolds in $M$ and introduce conditions on external curvature and torsion, which lead to a definition of a {\\em rigid sphere}. The main result is a local existence theorem concernig such spheres. For this purpose we apply the surjective implicit function theorem. The proof is based on a detailed analysis of the linearized problem and leads to an eight-parameter family of solutions in case when the metric tensor $g$ of $M$ is from a certain neighbourhood of the flat Minkowski metric. This contribution continues the study of rigid spheres in (Class. Quantum Grav. \\textbf{30} (2013), 175010, doi:10.1088/0264-9381/30/17/175010, 18 pp.).

  6. Rainfall Assimilation Using a New Four-Dimensional Variational Method: A Single-Point Observation Experiment

    Institute of Scientific and Technical Information of China (English)

    LIU Juanjuan; WANG Bin

    2011-01-01

    Accurate forecast of rainstorms associated with the mei-yu front has been an important issue for the Chinese economy and society. In July 1998 a heavy rainstorm hit the Yangzi River valley and received widespread attention from the public because it caused catastrophic damage in China. Several numerical studies have shown that many forecast models, including Pennsylvania State University National Center for Atmospheric Research's fifth-generation mesoscale model (MM5), failed to simulate the heavy precipitation over the Yangzi River valley. This study demonstrates that with the optimal initial conditions from the dimension-reduced projection four-dimensional variational data assimilation (DRP-4DVar) system, MM5 can successfully reproduce these observed rainfall amounts and can capture many important mesoscale features, including the southwestward shear line and the low-level jet stream. The study also indicates that the failure of previous forecasts can be mainly attributed to the lack of mesoscale details in the initial conditions of the models.

  7. Universal time versus relativistic time in four-dimensional symmetry framework

    International Nuclear Information System (INIS)

    A new four-dimensional symmetry framework with a universal time is investigated which can be realized by a radioactive clock--the measured survival fraction of unstable particles gives the elapsed time. The world picture turns out to be quite different from that in special relativity. The general space-light transformation and the nonuniversal speed of light in this framework are discussed. The difference between the one-way speed and the two-way speed of a light signal is considered in detail. Moreover, the discussion sheds light on the connection between the universality of the light speed and the clock which does not read universal time. The relation with special relativity theory is examined in a few cases

  8. The a-theorem for the four-dimensional gauged vector model

    CERN Document Server

    Schnitzer, Howard J

    2014-01-01

    The discussion of renormalization group flows in four-dimensional conformal field theories has recently focused on the a-anomaly. It has recently been shown that there is a monotonic decreasing function which interpolates between the ultraviolet and infrared fixed points such that \\Delta a = a_UV - a_IR > 0. The analysis has been extended to weakly relevant and marginal deformations, though there are few explicit examples involving interacting theories. In this paper we examine the a-theorem in the context of the gauged vector model which couples the usual vector model to the Banks-Zaks model. We consider the model to leading order in the 1/N expansion, all orders in the coupling constant \\lambda, and to second order in g^2. The model has both an IR and UV fixed point, and satisfies \\Delta a > 0.

  9. Live four-dimensional optical coherence tomography reveals embryonic cardiac phenotype in mouse mutant

    Science.gov (United States)

    Lopez, Andrew L., III; Wang, Shang; Larin, Kirill V.; Overbeek, Paul A.; Larina, Irina V.

    2015-09-01

    Efficient phenotyping of developmental defects in model organisms is critical for understanding the genetic specification of normal development and congenital abnormalities in humans. We previously reported that optical coherence tomography (OCT) combined with live embryo culture is a valuable tool for mouse embryo imaging and four-dimensional (4-D) cardiodynamic analysis; however, its capability for analysis of mouse mutants with cardiac phenotypes has not been previously explored. Here, we report 4-D (three-dimensional+time) OCT imaging and analysis of the embryonic heart in a Wdr19 mouse mutant, revealing a heart looping defect. Quantitative analysis of cardiac looping revealed a statistically significant difference between mutant and control embryos. Our results indicate that live 4-D OCT imaging provides a powerful phenotyping approach to characterize embryonic cardiac function in mouse models.

  10. Four-dimensional multiphoton microscopy with time-correlated single-photon counting.

    Science.gov (United States)

    Schönle, A; Glatz, M; Hell, S W

    2000-12-01

    We report on the implementation of fluorescence-lifetime imaging in multiphoton excitation microscopy that uses PC-compatible modules for time-correlated single-photon counting. Four-dimensional data stacks are produced with each pixel featuring fluorescence-decay curves that consist of as many as 4096 bins. Fluorescence lifetime(s) and their amplitude(s) are extracted by statistical methods at each pixel or in arbitrarily defined regions of interest. When employing an avalanche photodiode the width of the temporal response function is 420 ps. Although this response confines the temporal resolution to values greater than several hundreds of picoseconds, the lifetime precision is determined by the signal-to-noise ratio and can be in the range of tens of picosconds. Lifetime changes are visualized in pulsed-laser-deposited fluorescent layers as well as in cyan fluorescent proteins that transfer energy to yellow fluorescent proteins in live mammalian cells. PMID:18354639

  11. Berry curvature and four-dimensional monopoles in the relativistic chiral kinetic equation.

    Science.gov (United States)

    Chen, Jiunn-Wei; Pu, Shi; Wang, Qun; Wang, Xin-Nian

    2013-06-28

    We derive a relativistic chiral kinetic equation with manifest Lorentz covariance from Wigner functions of spin-1/2 massless fermions in a constant background electromagnetic field. It contains vorticity terms and a four-dimensional Euclidean Berry monopole which gives an axial anomaly. By integrating out the zeroth component of the 4-momentum p, we reproduce the previous three-dimensional results derived from the Hamiltonian approach, together with the newly derived vorticity terms. The phase space continuity equation has an anomalous source term proportional to the product of electric and magnetic fields (FσρF[over ˜]σρ∼EσBσ). This provides a unified interpretation of the chiral magnetic and vortical effects, chiral anomaly, Berry curvature, and the Berry monopole in the framework of Wigner functions.

  12. New classes of bi-axially symmetric solutions to four-dimensional Vasiliev higher spin gravity

    CERN Document Server

    Sundell, Per

    2016-01-01

    We present new infinite-dimensional spaces of bi-axially symmetric asymptotically anti-de Sitter solutions to four-dimensional Vasiliev higher spin gravity, obtained by modifications of the Ansatz used in arXiv:1107.1217, which gave rise to a Type-D solution space. The current Ansatz is based on internal semigroup algebras (without identity) generated by exponentials formed out of the bi-axial symmetry generators. After having switched on the vacuum gauge function, the resulting generalized Weyl tensor is given by the sum of two generalized Petrov type-D tensors, and the twistor space connections are smooth in twistor space over finite regions of spacetime. We provide evidence for that the linearized twistor space connection can be brought to Vasiliev gauge.

  13. Four-Dimensional Effective Supergravity and Soft Terms in M-Theory

    CERN Document Server

    Choi, K; Muñoz, C; Choi, Kiwoon; Kim, Hang Bae; Muñoz, Carlos

    1998-01-01

    We provide a simple macroscopic analysis of the four-dimensional effective supergravity of the Ho\\v{r}ava-Witten M-theory which is expanded in powers of $V$ and $\\rho$ denote the eleven-dimensional gravitational coupling, the Calabi-Yau volume and the eleventh length respectively. Possible higher order terms in the Kähler potential are identified and matched with the heterotic string corrections. In the context of this M-theory expansion, we analyze the soft supersymmetry-breaking terms under the assumption that supersymmetry is spontaneously broken by the auxiliary components of the bulk moduli superfields. It is examined how the pattern of soft terms changes when one moves from the weakly coupled heterotic string limit to the M-theory limit.

  14. Ultrafast core-loss spectroscopy in four-dimensional electron microscopy

    Directory of Open Access Journals (Sweden)

    Renske M. van der Veen

    2015-03-01

    Full Text Available We demonstrate ultrafast core-electron energy-loss spectroscopy in four-dimensional electron microscopy as an element-specific probe of nanoscale dynamics. We apply it to the study of photoexcited graphite with femtosecond and nanosecond resolutions. The transient core-loss spectra, in combination with ab initio molecular dynamics simulations, reveal the elongation of the carbon-carbon bonds, even though the overall behavior is a contraction of the crystal lattice. A prompt energy-gap shrinkage is observed on the picosecond time scale, which is caused by local bond length elongation and the direct renormalization of band energies due to temperature-dependent electron–phonon interactions.

  15. A four-dimensional primitive equation model for coupled coastal-deep ocean studies

    Science.gov (United States)

    Haidvogel, D. B.

    1981-01-01

    A prototype four dimensional continental shelf/deep ocean model is described. In its present form, the model incorporates the effects of finite amplitude topography, advective nonlinearities, and variable stratification and rotation. The model can be forced either directly by imposed atmospheric windstress and surface pressure distributions, and energetic mean currents imposed by the exterior oceanic circulation; or indirectly by initial distributions of shoreward propagation mesoscale waves and eddies. To avoid concerns over the appropriate specification of 'open' boundary conditions on the cross-shelf and seaward model boundaries, a periodic channel geometry (oriented along-coast) is used. The model employs a traditional finite difference expansion in the cross-shelf direction, and a Fourier (periodic) representation in the long-shelf coordinate.

  16. Berry curvature and four-dimensional monopoles in the relativistic chiral kinetic equation.

    Science.gov (United States)

    Chen, Jiunn-Wei; Pu, Shi; Wang, Qun; Wang, Xin-Nian

    2013-06-28

    We derive a relativistic chiral kinetic equation with manifest Lorentz covariance from Wigner functions of spin-1/2 massless fermions in a constant background electromagnetic field. It contains vorticity terms and a four-dimensional Euclidean Berry monopole which gives an axial anomaly. By integrating out the zeroth component of the 4-momentum p, we reproduce the previous three-dimensional results derived from the Hamiltonian approach, together with the newly derived vorticity terms. The phase space continuity equation has an anomalous source term proportional to the product of electric and magnetic fields (FσρF[over ˜]σρ∼EσBσ). This provides a unified interpretation of the chiral magnetic and vortical effects, chiral anomaly, Berry curvature, and the Berry monopole in the framework of Wigner functions. PMID:23848865

  17. Comparison of spirometry and abdominal height as four-dimensional computed tomography metrics in lung

    International Nuclear Information System (INIS)

    An important consideration in four-dimensional CT scanning is the selection of a breathing metric for sorting the CT data and modeling internal motion. This study compared two noninvasive breathing metrics, spirometry and abdominal height, against internal air content, used as a surrogate for internal motion. Both metrics were shown to be accurate, but the spirometry showed a stronger and more reproducible relationship than the abdominal height in the lung. The abdominal height was known to be affected by sensor placement and patient positioning while the spirometer exhibited signal drift. By combining these two, a normalization of the drift-free metric to tidal volume may be generated and the overall metric precision may be improved

  18. A four dimensional map for escape from resonance: negative energy modes and nonlinear instability

    CERN Document Server

    Martins, Caroline G L; Curry, C

    2016-01-01

    Positive definiteness of a Hamiltonian expanded about an equilibrium point provides only a necessary condition for stability, a criterion known as Dirichlet's theorem. The reason that this criterion is not necessary for stability is because of the possible existence of negative energy modes, which are linearly stable modes of oscillation that have negative energy. When such modes are present, the Hamiltonian is, in general, indefinite. Although such systems with negative energy modes are linearly stable (spectral stable), they are unstable to infinitesimal perturbations under the nonlinear dynamics. In the present work we study this kind of nonlinear instability with the simplest nontrivial four dimensional area-preserving map, which has a cubic degree of freedom, that was designed to mimic the behavior of a Hamiltonian system with one positive and one negative energy mode, and a quadratic degree of freedom, that allows eventual escapes in phase space, usually called as Arnold diffusion.

  19. Risk assessment methods in radiotherapy: Probabilistic safety assessment (PSA); Los metodos de analisis de riesgo en radioterapia: Analisis Probabilistico de seguridad (APS)

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Vera, M. L.; Perez Mulas, A.; Delgado, J. M.; Barrientos Ontero, M.; Somoano, F.; Alvarez Garcia, C.; Rodriguez Marti, M.

    2011-07-01

    The understanding of accidents that have occurred in radiotherapy and the lessons learned from them are very useful to prevent repetition, but there are other risks that have not been detected to date. With a view to identifying and preventing such risks, proactive methods successfully applied in other fields, such as probabilistic safety assessment (PSA), have been developed. (Author)

  20. Nutritional status of patients treated with radiotherapy as determined by subjective global assessment

    Energy Technology Data Exchange (ETDEWEB)

    Koom, Woong Sub; Keum, Ki Chang [Dept. of Radiation Oncology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Ahn, Seung Do [Dept. of Radiation Oncology, Asan Medical Center, Seoul (Korea, Republic of); and others

    2012-09-15

    The purpose of this prospective multi-institutional study was to evaluate the nutritional status of patients undergoing radiotherapy (RT) for treatment of head and neck, lung, or gastrointestinal cancer. A total of 1,000 patients were enrolled in this study at seven different hospitals in Seoul, Korea between October 2009 and May 2010. The nutritional status of patients after receiving 3 weeks of RT was evaluated using subjective global assessment (SGA). The nutritional status of each patient was rated as well nourished (A), moderately malnourished (B), or severely malnourished (C). The mean age of patients in this study was 59.4 {+-} 11.9 years, and the male to female ratio was 7:3. According to the SGA results, 60.8%, 34.5%, and 4.7% of patients were classified as A, B, or C, respectively. The following criteria were significantly associated with malnutrition (SGA B or C; p < 0.001): loss of subcutaneous fat or muscle wasting (odds ratio [OR], 11.473); increased metabolic demand/stress (OR, 8.688); ankle, sacral edema, or ascites (OR, 3.234); and weight loss 5% (OR, 2.299). SGA was applied successfully to assess the nutritional status of most patients. The prevalence of malnutrition in a radiation oncology department was 39.2%. The results of this study serve as a basis for implementation of nutrition intervention to patients being treated at radiation oncology departments.

  1. Texture analysis for the assessment of structural changes in parotid glands induced by radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: During radiotherapy (RT) for head-and-neck cancer, parotid glands undergo significant anatomic, functional and structural changes which could characterize pre-clinical signs of an increased risk of xerostomia. Texture analysis is proposed to assess structural changes of parotids induced by RT, and to investigate whether early variations of textural parameters (such as mean intensity and fractal dimension) can predict parotid shrinkage at the end of treatment. Material and methods: Textural parameters and volumes of 42 parotids from 21 patients treated with intensity-modulated RT for nasopharyngeal cancer were extracted from CT images. To individuate which parameters changed during RT, a Wilcoxon signed-rank test between textural indices (first and second RT week; first and last RT week) was performed. Discriminant analysis was applied to variations of these parameters in the first two weeks of RT to assess their power in predicting parotid shrinkage at the end of RT. Results: A significant decrease in mean intensity (1.7 HU and 3.8 HU after the second and last weeks, respectively) and fractal dimension (0.016 and 0.021) was found. Discriminant analysis, based on volume and fractal dimension, was able to predict the final parotid shrinkage (accuracy of 71.4%). Conclusion: Textural features could be used in combination with volume to characterize structural modifications on parotid glands and to predict parotid shrinkage at the end of RT

  2. Four-dimensional computed tomography (4DCT): A review of the current status and applications.

    Science.gov (United States)

    Kwong, Yune; Mel, Alexandra Olimpia; Wheeler, Greg; Troupis, John M

    2015-10-01

    The applications of conventional computed tomography (CT) have been widely researched and implemented in clinical practice. A recent technological innovation in the field of CT is the emergence of four-dimensional computed tomography (4DCT), where a three-dimensional computed tomography volume containing a moving structure is imaged over a period of time, creating a dynamic volume data set. 4DCT has previously been mainly utilised in the setting of radiation therapy planning, but with the development of wide field of view CT, 4DCT has opened major avenues in the diagnostic arena. The aim of this study is to provide a comprehensive narrative review of the literature regarding the current clinical applications of 4DCT. The applications reviewed include both routine diagnostic usage as well as an appraisal of the current research literature. A systematic review of the studies related to 4DCT was conducted. The Medline database was searched using the MeSH subject heading 'Four-Dimensional Computed Tomography'. After excluding non-human and non-English papers, 2598 articles were found. Further exclusion criteria were applied, including date range (since wide field of view CT was introduced in 2007), and exclusion of technical/engineering/physics papers. Further filtration of papers included identification of Review papers. This process yielded 67 papers. Of these, exclusion of papers not specifically discussing 4DCT (cone beam, 4D models) yielded 38 papers. As part of the review, the technique for 4DCT is described, with perspectives as to how it has evolved and its benefits in different clinical indications. PMID:26041442

  3. Quantitation of the reconstruction quality of a four-dimensional computed tomography process for lung cancer patients

    International Nuclear Information System (INIS)

    We have developed a four-dimensional computed tomography (4D CT) technique for mapping breathing motion in radiotherapy treatment planning. A multislice CT scanner (1.5 mm slices) operated in cine mode was used to acquire 12 contiguous slices in each couch position for 15 consecutive scans (0.5 s rotation, 0.25 s between scans) while the patient underwent simultaneous quantitative spirometry measurements to provide a sorting metric. The spirometry-sorted scans were used to reconstruct a 4D data set. A critical factor for 4D CT is quantifying the reconstructed data set quality which we measure by correlating the metric used relative to internal-object motion. For this study, the internal air content within the lung was used as a surrogate for internal motion measurements. Thresholding and image morphological operations were applied to delineate the air-containing tissues (lungs, trachea) from each CT slice. The Hounsfield values were converted to the internal air content (V). The relationship between the air content and spirometer-measured tidal volume (ν) was found to be quite linear throughout the lungs and was used to estimate the overall accuracy and precision of tidal volume-sorted 4D CT. Inspection of the CT-scan air content as a function of tidal volume showed excellent correlations (typically r>0.99) throughout the lung volume. Because of the discovered linear relationship, the ratio of internal air content to tidal volume was indicative of the fraction of air change in each couch position. Theoretically, due to air density differences within the lung and in room, the sum of these ratios would equal 1.11. For 12 patients, the mean value was 1.08±0.06, indicating the high quality of spirometry-based image sorting. The residual of a first-order fit between ν and V was used to estimate the process precision. For all patients, the precision was better than 8%, with a mean value of 5.1%±1.9%. This quantitative analysis highlights the value of using spirometry

  4. Four-Dimensional Variational Data Assimilation Experiments for a Heavy Rain Case During the 2002 IOP in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lin; NI Yunqi

    2005-01-01

    A heavy rainfall event along the mei-yu front during 22-23 June 2002 was chosen for this study. To assess the impact of the routine and additional IOP (intensive observation period) radiosonde observations on the mesoscale heavy rainfall forecast, a series of four-dimensional variational (4DVAR) data assimilation and model simulation experiments was conducted using nonhydrostatic mesoscale model MM5 and the MM5 4DVAR system. The effects of the intensive observations in the different areas on the heavy rainfall forecast were also investigated. The results showed that improvement of the forecast skill for mesoscale heavy rainfall intensity was possible from the assimilation of the IOP radiosonde observations. However,the impact of the IOP observations on the forecast of the rainfall pattern was not significant. Initial conditions obtained through the 4DVAR experiments with a 12-h assimilation window were capable of improving the 24-h forecast. The simulated results after the assimilation showed that it would be best to perform the intensive radiosonde observations in the upstream of the rainfall area and in the moisture passageway area at the same time. Initial conditions created by the 4DVAR led to the low-level moisture convergence over the rainfall area, enhanced frontogenesis and upward motion within the mei-yu front,and intensified middle- and high-level unstable stratification in front of the mei-yu front. Consequently,the heavy rainfall forecast was improved.

  5. Results of postoperative 90Sr radiotherapy of keloids in view of patients' subjective assessment

    International Nuclear Information System (INIS)

    Background and Purpose: As treatment of keloids is mainly a cosmetic indication, the authors investigated, beyond the recurrence rate, the patients' satisfaction with the result and its correlation with objective medical findings. Patients and Methods: 83 keloids of 66 patients had been irradiated after excision by a uniform protocol with 4 x 5 Gy (strontium-90 [90Sr] surface applicator). A questionnaire was developed and sent out in which, above all, the satisfaction with the therapeutic and cosmetic outcome was obtained. These results were correlated with objective parameters and medical findings which were ascertained during an extra follow-up examination. Results: Among 18 of the 41 patients (44%), who had answered the questionnaire, 19 of the 53 keloids treated (36%) had relapsed. 61% of the patients were extremely or mainly satisfied with the therapeutic outcome, 51% extremely or mainly satisfied with the cosmetic outcome. The relief from former keloid-caused symptoms (therapeutic outcome: p=0.0005; cosmetic outcome: p=0.0011), the ear as keloid localization (p=0.0008 and p=0.0197), and male gender (therapeutic outcome: p=0.0423) were significantly associated with higher satisfaction. The recurrence rate as well as the extent of radiation side effects had no significant influence on patients' assessment. Conclusion: Cosmetic aspects like the dermal side effects and the patients' satisfaction should be taken into account when evaluating the results of radiotherapy in keloids. (orig.)

  6. Tumor shrinkage assessed by volumetric MRI in the long-term follow-up after stereotactic radiotherapy of meningiomas

    Energy Technology Data Exchange (ETDEWEB)

    Astner, Sabrina T.; Theodorou, Marilena; Dobrei-Ciuchendea, Mihaela; Kopp, Christine; Molls, Michael [Dept. of Radiotherapy and Radiooncology, Klinikum rechts der Isar, Technical Univ. of Munich (Germany); Auer, Florian [Dept. of Neuroradiology, Klinikum rechts der Isar, Technical Univ. of Munich (Germany); Grosu, Anca-Ligia [Dept. of Radiotherapy, Univ. Hospital Freiburg (Germany)

    2010-08-15

    Purpose: To evaluate tumor volume reduction in the follow-up of meningiomas after fractionated stereotactic radiotherapy (FSRT) or linac radiosurgery (RS) by using magnetic resonance imaging (MRI). Patients and Methods: In 59 patients with skull base meningiomas, gross tumor volume (GTV) was outlined on contrast-en-hanced MRI before and median 50 months (range 11-92 months) after stereotactic radiotherapy. MRI was performed as an axial three-dimensional gradient-echo T1-weighted sequence at 1.6 mm slice thickness without gap (3D-MRI). Results were compared to the reports of diagnostic findings. Results: Mean tumor size of all 59 meningiomas was 13.9 ml (0.8-62.9 ml) before treatment. There was shrinkage of the treated meningiomas in all but one patient. Within a median volumetric follow-up of 50 months (11-95 months), an absolute mean volume reduction of 4 ml (0-18 ml) was seen. The mean relative size reduction compared to the volume before radiotherapy was 27% (0-73%). Shrinkage measured by 3D-MRI was greater at longer time intervals after radiotherapy. The mean size reduction was 17%, 23%, and 30% (at < 24 months, 24-48 months, and 48-72 months). Conclusion: By using 3D-MRI in almost all patients undergoing radiotherapy of a meningioma, tumor shrinkage is detected. The data presented here demonstrate that volumetric assessment from 3D-MRI provides additional information to routinely used radiologic response measurements. After FSRT or RS, a mean size reduction of 25-45% can be expected within 4 years. (orig.)

  7. Abnormal Nuclear Variations in Response to Radiotherapy- As a Tool in Treatment Planning and Assessment of Prognosis

    Science.gov (United States)

    Naithani, Manisha; Kaur, Sohinder; Reddy, K.S.; Pasi, Rachna

    2016-01-01

    Introduction The treatment approaches for oral squamous cell carcinoma (OSCC) include single management with surgery, radiotherapy, along with chemotherapy or various combinations of these modalities. The estimation of radio sensitivity of individual tumours is essential for planning the optimum radiation schedule for each patient. Assessment of radiation induced histo morphological changes in the nucleus is a known marker of radiosensitivity. Aim The aim of this study was to establish the relationship between nuclear changes with radiation dose and to investigate the prospect of utilizing them as an assay to predict tumour response to radiotherapy in oral cancers. Materials and Methods The present study included 50 patients (age range of 30-65yrs) with histopathologically confirmed squamous cell carcinoma of oral mucosa and being treated by radiotherapy alone with a radiation dose schedule of 4, 14, 24 and 60 Gy respectively at 2nd, 7th, 12th and 30th day. From the included patients, smear of the buccal mucosa was collected and was air dried and fixed with methanol. The Nuclear changes of Micronucleus (MN), Nuclear Budding (NB) and Multinucleation (MNU) were evaluated under the bright field microscopy after staining with Giemsa and May-Grunwald’s stain. Results Out of the 50, 37(74%) were males and 13(26%) were females (Ratio 3:1). The mean percentage increase of MN and MNU were found to be statistically significant (p=0.001) when compared with pre-treatment day. Similar findings were seen with NB, except between pretreatment and after 14 Gy (p-0.110). In the present study the measurement of relative increment index done in respect to all nuclear abnormalities show a sustained increase with increasing dosage of radiation. Conclusion The present study, was undertaken to explore the possibility of establishing a relationship between the frequencies of nuclear abnormalities in patients with oral cancer with applied dosage and duration of radiotherapy. The

  8. Chiral Four-Dimensional F-Theory Compactifications With SU(5) and Multiple U(1)-Factors

    CERN Document Server

    Cvetič, Mirjam; Klevers, Denis; Piragua, Hernan

    2013-01-01

    We develop geometric techniques to determine the spectrum and the chiral indices of matter multiplets for four-dimensional F-theory compactifications on elliptic Calabi-Yau fourfolds with rank two Mordell-Weil group. The general elliptic fiber is the Calabi-Yau onefold in dP_2. We classify its resolved elliptic fibrations over a general base B. The study of singularities of these fibrations leads to explicit matter representations, that we determine both for U(1)xU(1) and SU(5)xU(1)xU(1) constructions. We determine for the first time certain matter curves and surfaces using techniques involving prime ideals. The vertical cohomology ring of these fourfolds is calculated for both cases and general formulas for the Euler numbers are derived. Explicit calculations are presented for a specific base B=P^3. We determine the general G_4-flux that belongs to H^{(2,2)}_V of the resolved Calabi-Yau fourfolds. As a by-product, we derive for the first time all conditions on G_4-flux in general F-theory compactifications w...

  9. A four-dimensional virtual hand brain–machine interface using active dimension selection

    Science.gov (United States)

    Rouse, Adam G.

    2016-06-01

    Objective. Brain–machine interfaces (BMI) traditionally rely on a fixed, linear transformation from neural signals to an output state-space. In this study, the assumption that a BMI must control a fixed, orthogonal basis set was challenged and a novel active dimension selection (ADS) decoder was explored. Approach. ADS utilizes a two stage decoder by using neural signals to both (i) select an active dimension being controlled and (ii) control the velocity along the selected dimension. ADS decoding was tested in a monkey using 16 single units from premotor and primary motor cortex to successfully control a virtual hand avatar to move to eight different postures. Main results. Following training with the ADS decoder to control 2, 3, and then 4 dimensions, each emulating a grasp shape of the hand, performance reached 93% correct with a bit rate of 2.4 bits s‑1 for eight targets. Selection of eight targets using ADS control was more efficient, as measured by bit rate, than either full four-dimensional control or computer assisted one-dimensional control. Significance. ADS decoding allows a user to quickly and efficiently select different hand postures. This novel decoding scheme represents a potential method to reduce the complexity of high-dimension BMI control of the hand.

  10. Four-dimensional formulation of the sector-improved residue subtraction scheme

    International Nuclear Information System (INIS)

    Four years ago, one of us introduced a novel subtraction scheme [1] for the evaluation of double-real radiation contributions to cross sections at next-to-next-to-leading order (NNLO) in QCD. This approach, named SecToR Improved Phase sPacE for Real radiation (STRIPPER), has already found several non-trivial applications. In particular, it has allowed for the determination of NNLO corrections to hadronic top-quark pair production, fully differential top-quark decays, inclusive semileptonic charmless b-quark decays, associated Higgs boson and jet production in gluon fusion, muon decay spin asymmetry, and t-channel single-top production. Common to these calculations was the use of conventional dimensional regularization (CDR). In this publication, we present a complete formulation of the subtraction scheme for arbitrary processes with any number of colored partons in the final state, and up to two partons in the initial state. Furthermore, we modify the integrated subtraction terms of the double-real radiation to enable the introduction of the 't Hooft–Veltman version of dimensional regularization (HV), in which resolved states are four-dimensional. We demonstrate the correctness of our approach on the example of top-quark pair production in the gluon fusion channel

  11. Four-dimensional computed tomography (4D CT). Concepts and preliminary development

    International Nuclear Information System (INIS)

    Four-dimensional computed tomography (4D CT) is a dynamic volume imaging system of moving organs with an image quality comparable to that of conventional CT. 4D CT will be realized by several technical breakthroughs for dynamic cone-beam CT: a large-area two-dimensional (2D) detector; high-speed data transfer system; reconstruction algorithms; ultra-high-speed reconstruction computer; and high-speed, continuously rotating gantry. Among these, development of the 2D detector is one of the main tasks because it should have as wide a dynamic range and as high a data acquisition speed (view rate) as present CT detectors. We are now developing a 4D CT scanner together with the key components. It will take one volume image in 0.5 sec with a 3D matrix of 512 x 512 x 512. This paper describes the concepts and designs of the 4D CT system, as well as preliminary development of the 2D detector. (author)

  12. Towards a coupled ocean-wave-atmosphere four dimensional data assimilation system

    Science.gov (United States)

    Ngodock, Hans; Carrier, Matthew; Amerault, Clark; Campbell, Timothy; Holt, Teddy; Xu, Liang; Rowley, Clark

    2015-04-01

    Individual 4dvar systems have been developed at the Naval Research Laboratory (NRL) for the ocean model (Navy coastal ocean model, NCOM), the wave model (simulating waves in the nearshore, SWAN) and the atmospheric component of the coupled ocean-atmosphere mesoscale prediction system (COAMPS). Although the three models within COAPMS are coupled in the forward integration, the initialization of each model is done separately. The coupled system forecast is hindered, however, by the lack of a fully coupled and dynamically balanced ocean-atmosphere analysis. A recent work by Ngodock and Carrier (2013) has highlighted this shortcoming with the NCOM-4DVAR, showing that while the NCOM-4DVAR is able to adjust the ocean state properly, the resulting ocean forecast degrades quickly due to the fact that the atmospheric state has not also been adjusted relative to the ocean observations. Likewise, . Currently, the coupled model is initialized using separate analyses for the ocean and atmosphere that do not account for observations in the adjacent fluid. The lack of a coupled analysis produces shocks in the coupled model in the form of gravity waves that degrade the information gained through DA and increase the error in the coupled forecast. The goal of this presentation is to describe ongoing developments at NRL in building a fully coupled ocean-wave-atmosphere four-dimensional variational (4dvar) data assimilation system using the Earth System Modeling Framework (ESMF).

  13. Coupling Ensemble Kalman Filter with Four-dimensional Variational Data Assimilation

    Institute of Scientific and Technical Information of China (English)

    Fuqing ZHANG; Meng ZHANG; James A. HANSEN

    2009-01-01

    This study examines the performance of coupling the deterministic four-dimensional variational assimilation system (4DVAR) with an ensemble Kalman filter (EnKF) to produce a superior hybrid approach for data assimilation. The coupled assimilation scheme (E4DVAR) benefits from using the state-dependent uncertainty provided by EnKF while taking advantage of 4DVAR in preventing filter divergence: the 4DVAR analysis produces posterior maximum likelihood solutions through minimization of a cost function about which the ensemble perturbations are transformed, and the resulting ensemble analysis can be propagated forward both for the next assimilation cycle and as a basis for ensemble forecasting. The feasibility and effectiveness of this coupled approach are demonstrated in an idealized model with simulated observations. It is found that the E4DVAR is capable of outperforming both 4DVAR and the EnKF under both perfect-and imperfect-model scenarios. The performance of the coupled scheme is also less sensitive to either the ensemble size or the assimilation window length than those for standard EnKF or 4DVAR implementations.

  14. The Estimation of Regional Crop Yield Using Ensemble-Based Four-Dimensional Variational Data Assimilation

    Directory of Open Access Journals (Sweden)

    Zhiwei Jiang

    2014-03-01

    Full Text Available To improve crop model performance for regional crop yield estimates, a new four-dimensional variational algorithm (POD4DVar merging the Monte Carlo and proper orthogonal decomposition techniques was introduced to develop a data assimilation strategy using the Crop Environment Resource Synthesis (CERES-Wheat model. Two winter wheat yield estimation procedures were conducted on a field plot and regional scale to test the feasibility and potential of the POD4DVar-based strategy. Winter wheat yield forecasts for the field plots showed a coefficient of determination (R2 of 0.73, a root mean square error (RMSE of 319 kg/ha, and a relative error (RE of 3.49%. An acceptable yield at the regional scale was estimated with an R2 of 0.997, RMSE of 7346 tons, and RE of 3.81%. The POD4DVar-based strategy was more accurate and efficient than the EnKF-based strategy. In addition to crop yield, other critical crop variables such as the biomass, harvest index, evapotranspiration, and soil organic carbon may also be estimated. The present study thus introduces a promising approach for operationally monitoring regional crop growth and predicting yield. Successful application of this assimilation model at regional scales must focus on uncertainties derived from the crop model, model inputs, data assimilation algorithm, and assimilated observations.

  15. Almost conformal transformation in a four dimensional Riemannian manifold with an additional structure

    CERN Document Server

    Dokuzova, Iva

    2011-01-01

    We consider a four dimensional Riemannian manifold M with a metric g and affinor structure q. The local coordinates of these tensors are circulant matrices. Their first orders are (A, B, C, B), A, B, C\\in FM and (0, 1, 0, 0), respectively. We construct another metric \\tilde{g} on M. We find the conditions for \\tilde{g} to be a positively defined metric, and for q to be a parallel structure with respect to the Riemannian connection of g. Further, let x be an arbitrary vector in T_{p}M, where p is a point on M. Let \\phi and \\phi be the angles between x and qx, x and q^{2}x with respect to g. We express the angles between x and qx, x and q^{2}x with respect to $\\tilde{g}$ with the help of the angles $\\phi$ and \\phi. Also,we construct two series {\\phi_{n}}and {\\phi_{n}}. We prove that every of it is an increasing one and it is converge.

  16. Relativistic positioning: four-dimensional numerical approach in Minkowski space-time

    CERN Document Server

    Puchades, Neus

    2011-01-01

    We simulate the satellite constellations of two Global Navigation Satellite Systems: Galileo (EU) and GPS (USA). Satellite motions in Minkowski space-time are described in an inertial frame with the origin at the center of an idealized spherically symmetric non rotating Earth. The trajectories are then circumferences centered at the same point as Earth. In Minkowski space-time, there is a well known relation (see B. Coll, J. J. Ferrando and J. A. Morales-Lladosa, Class. Quantum Grav., 27, 065013, 2010) between the emission and inertial coordinates of any event. Here, this relation is implemented in a numerical code, which is tested and applied. The first application is a detailed numerical four-dimensional analysis of the so-called emission coordinate region and co-region. In a second application, a GPS (Galileo) satellite is considered as the receiver and its emission coordinates are given by four Galileo (GPS) satellites. The bifurcation problem (double localization) in the positioning of the receiver satel...

  17. Simulations of four-dimensional simplicial quantum gravity as dynamical triangulation

    Energy Technology Data Exchange (ETDEWEB)

    Agishtein, M.E.; Migdal, A.A. (Program in Applied and Computational Mathematics, Fine Hall, Princeton Univ., Princeton, NJ (US))

    1992-04-20

    In this paper, Four-Dimensional Simplicial Quantum Gravity is simulated using the dynamical triangulation approach. The authors studied simplicial manifolds of spherical topology and found the critical line for the cosmological constant as a function of the gravitational one, separating the phases of opened and closed Universe. When the bare cosmological constant approaches this line from above, the four-volume grows: the authors reached about 5 {times} 10{sup 4} simplexes, which proved to be sufficient for the statistical limit of infinite volume. However, for the genuine continuum theory of gravity, the parameters of the lattice model should be further adjusted to reach the second order phase transition point, where the correlation length grows to infinity. The authors varied the gravitational constant, and they found the first order phase transition, similar to the one found in three-dimensional model, except in 4D the fluctuations are rather large at the transition point, so that this is close to the second order phase transition. The average curvature in cutoff units is large and positive in one phase (gravity), and small negative in another (antigravity). The authors studied the fractal geometry of both phases, using the heavy particle propagator to define the geodesic map, as well as with the old approach using the shortest lattice paths.

  18. Combining four dimensional variational data assimilation and particle filtering for estimating volcanic ash emissions

    Science.gov (United States)

    Franke, Philipp; Elbern, Hendrik

    2016-04-01

    Estimating volcanic ash emissions is a very challenging task due to limited monitoring capacities of the ash plume and nonlinear processes in the atmosphere, which renders application of source strength and injection height estimations difficult. Most models, which estimate volcanic ash emissions, make strong simplifications of the dispersion of volcanic ash and corresponding atmospheric processes. The objective of this work is to estimate volcanic ash emissions and simulate the ensuing dispersion applying a full chemistry transport model in a hybrid approach by using its adjoint as well as an ensemble of model runs to quantify forecast uncertainties. Therefore, the four dimensional variational data assimilation version of the EURAD-IM chemistry transport model is extended to include a Sequential Importance Resampling Smoother (SIRS), introducing novel weighting and resampling strategies. In the main SIRS step the ensemble members exchange high rated emission patterns while rejecting emission patterns with low value for the forecast. The emission profiles of the ensemble members are perturbed afterwards to guarantee different emissions for all ensemble members. First identical twin experiments show the ability of the system to estimate the temporal and vertical distribution of volcanic ash emissions. The 4D-var data assimilation algorithm of the new system additionally provides quantitative emission estimation.

  19. Monocosm a linear solution to the effective four-dimensionality problem

    CERN Document Server

    Trifonov, V Yu

    1995-01-01

    In this note we formalize certain aspects of measurement \\textit{(active observation)} process which makes it possible to express in strict terms the concept of rational behaviour and degree to which logic of the observer determines what he perceives. This leads to a first-order theory shown to possess a real-world model: if a resercher's logic is Boolean, he is bound to perceive his spacetime as a four-dimensional pseudo-Riemannian manifold of signature 2, with a big-bang geometry. These connections between the type of an observer's logic and large-scale structure of the observable universe generate a testable effect similar to the action of a positive cosmological constant, imply Haar integration-over-spacetime and also provide a heuristic limit on the number of matter generations. The result casts some doubts (arising also from the necessity of renormalization procedures and other difficulties of Gauge-Grassmannian schemes) that \\textit{classical} mathematics (i.e. the mathematics of the topos of sets) is ...

  20. Generating one-, two-, three- and four-scroll attractors from a novel four-dimensional smooth autonomous chaotic system

    International Nuclear Information System (INIS)

    A new four-dimensional quadratic smooth autonomous chaotic system is presented in this paper, which can exhibit periodic orbit and chaos under the conditions on the system parameters. Importantly, the system can generate one-, two-, three- and four-scroll chaotic attractors with appropriate choices of parameters. Interestingly, all the attractors are generated only by changing a single parameter. The dynamic analysis approach in the paper involves time series, phase portraits, Poincaré maps, a bifurcation diagram, and Lyapunov exponents, to investigate some basic dynamical behaviours of the proposed four-dimensional system. (general)

  1. Estimate of the Critical Exponent of the Anderson Transition in the Three and Four-Dimensional Unitary Universality Classes

    Science.gov (United States)

    Slevin, Keith; Ohtsuki, Tomi

    2016-10-01

    Disordered non-interacting systems are classified into ten symmetry classes, with the unitary class being the most fundamental. The three and four-dimensional unitary universality classes are attracting renewed interest because of their relation to three-dimensional Weyl semi-metals and four-dimensional topological insulators. Determining the critical exponent of the correlation/localisation length for the Anderson transition in these classes is important both theoretically and experimentally. Using the transfer matrix technique, we report numerical estimations of the critical exponent in a U(1) model in three and four dimensions.

  2. Chiral four-dimensional F-theory compactifications with SU(5) and multiple U(1)-factors

    Science.gov (United States)

    Cvetič, Mirjam; Grassi, Antonella; Klevers, Denis; Piragua, Hernan

    2014-04-01

    We develop geometric techniques to determine the spectrum and the chiral indices of matter multiplets for four-dimensional F-theory compactifications on elliptic Calabi-Yau fourfolds with rank two Mordell-Weil group. The general elliptic fiber is the Calabi-Yau onefold in dP 2. We classify its resolved elliptic fibrations over a general base B. The study of singularities of these fibrations leads to explicit matter representations, that we determine both for U(1) × U(1) and SU(5) × U(1) × U(1) constructions. We determine for the first time certain matter curves and surfaces using techniques involving prime ideals. The vertical cohomology ring of these fourfolds is calculated for both cases and general formulas for the Euler numbers are derived. Explicit calculations are presented for a specific base B = ℙ3. We determine the general G 4-flux that belongs to of the resolved Calabi-Yau fourfolds. As a by-product, we derive for the first time all conditions on G 4-flux in general F-theory compactifications with a non-holomorphic zero section. These conditions have to be formulated after a circle reduction in terms of Chern-Simons terms on the 3D Coulomb branch and invoke M-theory/F-theory duality. New Chern-Simons terms are generated by Kaluza-Klein states of the circle compactification. We explicitly perform the relevant field theory computations, that yield non-vanishing results precisely for fourfolds with a non-holomorphic zero section. Taking into account the new Chern-Simons terms, all 4D matter chiralities are determined via 3D M-theory/F-theory duality. We independently check these chiralities using the subset of matter surfaces we determined. The presented techniques are general and do not rely on toric data.

  3. Mesoscale modeling and four-dimensional data assimilation in areas of highly complex terrain

    International Nuclear Information System (INIS)

    A multiscale four-dimensional data assimilation (FDDA) technique, based on Newtonian relaxation, is incorporated into a mesoscale model and evaluated using meteorological and tracer data collected during a field experiment. The mesoscale model is used to predict synoptically driven flows and small-scale circulations influenced by terrain near the Rocky Flats Plant (RFP) for four nocturnal periods. Data assimilation is used to create dynamically consistent analysis fields based on mesoscale forecasts and asynoptic data. Observations from towers, minisodars, airsondes, tethersondes, rawinsondes, and profilers near RFP, as well as observations from surface stations throughout Colorado, are incorporated into the high-resolution analysis fields. Wind and turbulence quantities produced by the mesoscale model are used to determine the dispersion of tracer released from RFP for each evening. A subjective and statistical evaluation of meteorological and dispersion results is performed to examine FDDA effects on nocturnal circulations and tracer transport. The mesoscale model is able to qualitatively predict the mesobeta-scale drainage flows; however, the largest wind forecast errors occurred in a region immediately adjacent to the foothills. The FDDA technique reduced overall errors in the atmospheric and dispersion calculations, while the model generated realistic small-scale circulations not resolved by the data. Still, the model did not capture the shallow surface drainage flows east of RFP for two evenings during the field experiment. When the model was initialized with high-resolution analysis fields generated by FDDA and left to forecast, little improvement in forecasts were seen two hours after initialization time. This may be due to the fact that only observed horizontal wind components were assimilated into the analyses generated by FDDA; assimilation of temperature observations was not included. 32 refs., 12 figs., 4 tabs

  4. Evaluating four-dimensional time-lapse electrical resistivity tomography for monitoring DNAPL source zone remediation.

    Science.gov (United States)

    Power, Christopher; Gerhard, Jason I; Karaoulis, Marios; Tsourlos, Panagiotis; Giannopoulos, Antonios

    2014-07-01

    Practical, non-invasive tools do not currently exist for mapping the remediation of dense non-aqueous phase liquids (DNAPLs). Electrical resistivity tomography (ERT) exhibits significant potential but has not yet become a practitioner's tool due to challenges in interpreting the survey results at real sites. This study explores the effectiveness of recently developed four-dimensional (4D, i.e., 3D space plus time) time-lapse surface ERT to monitor DNAPL source zone remediation. A laboratory experiment demonstrated the approach for mapping a changing NAPL distribution over time. A recently developed DNAPL-ERT numerical model was then employed to independently simulate the experiment, providing confidence that the DNAPL-ERT model is a reliable tool for simulating real systems. The numerical model was then used to evaluate the potential for this approach at the field scale. Four DNAPL source zones, exhibiting a range of complexity, were initially simulated, followed by modeled time-lapse ERT monitoring of complete DNAPL remediation by enhanced dissolution. 4D ERT inversion provided estimates of the regions of the source zone experiencing mass reduction with time. Results show that 4D time-lapse ERT has significant potential to map both the outline and the center of mass of the evolving treated portion of the source zone to within a few meters in each direction. In addition, the technique can provide a reasonable, albeit conservative, estimate of the DNAPL volume remediated with time: 25% underestimation in the upper 2m and up to 50% underestimation at late time between 2 and 4m depth. The technique is less reliable for identifying cleanup of DNAPL stringers outside the main DNAPL body. Overall, this study demonstrates that 4D time-lapse ERT has potential for mapping where and how quickly DNAPL mass changes in real time during site remediation.

  5. Complete classification of parallel Lorentz surfaces in four-dimensional neutral pseudosphere

    Science.gov (United States)

    Chen, Bang-Yen

    2010-08-01

    A Lorentz surface of an indefinite space form is called parallel if its second fundamental form is parallel with respect to the Van der Waerden-Bortolotti connection. Such surfaces are locally invariant under the reflection with respect to the normal space at each point. Parallel surfaces are important in geometry as well as in general relativity since extrinsic invariants of such surfaces do not change from point to point. Parallel Lorentz surfaces in four-dimensional (4D) Lorentzian space forms are classified by Chen and Van der Veken ["Complete classification of parallel surfaces in 4-dimensional Lorentz space forms," Tohoku Math. J. 61, 1 (2009)]. Recently, explicit classification of parallel Lorentz surfaces in the pseudo-Euclidean 4-space E24 and in the pseudohyperbolic 4-space H24(-1) are obtained recently by Chen et al. ["Complete classification of parallel Lorentzian surfaces in Lorentzian complex space forms," Int. J. Math. 21, 665 (2010); "Complete classification of parallel Lorentz surfaces in neutral pseudo hyperbolic 4-space," Cent. Eur. J. Math. 8, 706 (2010)], respectively. In this article, we completely classify the remaining case; namely, parallel Lorentz surfaces in 4D neutral pseudosphere S24(1). Our result states that there are 24 families of such surfaces in S24(1). Conversely, every parallel Lorentz surface in S24(1) is obtained from one of the 24 families. The main result indicates that there are major differences between Lorentz surfaces in the de Sitter 4-space dS4 and in the neutral pseudo 4-sphere S24.

  6. Complete classification of parallel Lorentz surfaces in four-dimensional neutral pseudosphere

    International Nuclear Information System (INIS)

    A Lorentz surface of an indefinite space form is called parallel if its second fundamental form is parallel with respect to the Van der Waerden-Bortolotti connection. Such surfaces are locally invariant under the reflection with respect to the normal space at each point. Parallel surfaces are important in geometry as well as in general relativity since extrinsic invariants of such surfaces do not change from point to point. Parallel Lorentz surfaces in four-dimensional (4D) Lorentzian space forms are classified by Chen and Van der Veken [''Complete classification of parallel surfaces in 4-dimensional Lorentz space forms,'' Tohoku Math. J. 61, 1 (2009)]. Recently, explicit classification of parallel Lorentz surfaces in the pseudo-Euclidean 4-space E24 and in the pseudohyperbolic 4-space H24(-1) are obtained recently by Chen et al. [''Complete classification of parallel Lorentzian surfaces in Lorentzian complex space forms,'' Int. J. Math. 21, 665 (2010); ''Complete classification of parallel Lorentz surfaces in neutral pseudo hyperbolic 4-space,'' Cent. Eur. J. Math. 8, 706 (2010)], respectively. In this article, we completely classify the remaining case; namely, parallel Lorentz surfaces in 4D neutral pseudosphere S24(1). Our result states that there are 24 families of such surfaces in S24(1). Conversely, every parallel Lorentz surface in S24(1) is obtained from one of the 24 families. The main result indicates that there are major differences between Lorentz surfaces in the de Sitter 4-space dS4 and in the neutral pseudo 4-sphere S24.

  7. A New Global Four-Dimensional Variational Ocean Data Assimilation System and Its Application

    Institute of Scientific and Technical Information of China (English)

    LIU Juan; WANG Bin; LIU Hailong; YU Yongqiang

    2008-01-01

    A four-dimensional variational data assimilation (4DVar) system of the LASG/IAP Climate Ocean Model, version 1.0 (LICOM1.0), named LICOM-3DVM, has been developed using the three-dimensional variational data assimilation of mapped observation (3DVM), a 4DVar method newly proposed in the past two years. Two experiments with 12-year model integrations were designed to validate it. One is the as- similation run, called ASSM, which incorporated the analyzed weekly sea surface temperature (SST) fields from Reynolds and Smith (OISST) between 1990 and 2001 once a week by the LICOM-3DVM. The other is the control run without any assimilation, named CTL. ASSM shows that the simulated temperatures of the upper ocean (above 50 meters), especially the SST of equatorial Pacific, coincide with the Tropic Atmo- sphere Ocean (TAO) mooring data, the World Ocean Atlas 2001 (WOA01) data and the Met Office Hadley Centre's sea ice and sea surface temperature (HadISST) data. It decreased the cold bias existing in CTL in the eastern Pacific and produced a Nino index that agrees with observation well. The validation results suggest that the LICOM-3DVM is able to effectively adjust the model results of the ocean temperature, although it's hard to correct the subsurface results and it even makes them worse in some areas due to the incorporation of only surface data. Future development of the LICOM-3DVM is to include subsurface in situ observations and satellite observations to further improve model simulations.

  8. Impact of four-dimensional data assimilation (FDDA) on urban climate analysis

    Science.gov (United States)

    Pan, Linlin; Liu, Yubao; Liu, Yuewei; Li, Lei; Jiang, Yin; Cheng, Will; Roux, Gregory

    2015-12-01

    This study investigates the impact of four-dimensional data assimilation (FDDA) on urban climate analysis, which employs the NCAR (National Center for Atmospheric Research) WRF (the weather research and forecasting model) based on climate FDDA (CFDDA) technology to develop an urban-scale microclimatology database for the Shenzhen area, a rapidly developing metropolitan located along the southern coast of China, where uniquely high-density observations, including ultrahigh-resolution surface AWS (automatic weather station) network, radio sounding, wind profilers, radiometers, and other weather observation platforms, have been installed. CFDDA is an innovative dynamical downscaling regional climate analysis system that assimilates diverse regional observations; and has been employed to produce a 5 year multiscale high-resolution microclimate analysis by assimilating high-density observations at Shenzhen area. The CFDDA system was configured with four nested-grid domains at grid sizes of 27, 9, 3, and 1 km, respectively. This research evaluates the impact of assimilating high-resolution observation data on reproducing the refining features of urban-scale circulations. Two experiments were conducted with a 5 year run using CFSR (climate forecast system reanalysis) as boundary and initial conditions: one with CFDDA and the other without. The comparisons of these two experiments with observations indicate that CFDDA greatly reduces the model analysis error and is able to realistically analyze the microscale features such as urban-rural-coastal circulation, land/sea breezes, and local-hilly terrain thermal circulations. It is demonstrated that the urbanization can produce 2.5 k differences in 2 m temperatures, delays/speeds up the land/sea breeze development, and interacts with local mountain-valley circulations.

  9. TH-A-19A-10: Fast Four Dimensional Monte Carlo Dose Computations for Proton Therapy of Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mirkovic, D; Titt, U; Mohan, R [U.T M.D. Anderson Cancer Center, Houston, TX (United States); Yepes, P [Rice University, Houston, TX (United States)

    2014-06-15

    Purpose: To develop and validate a fast and accurate four dimensional (4D) Monte Carlo (MC) dose computation system for proton therapy of lung cancer and other thoracic and abdominal malignancies in which the delivered dose distributions can be affected by respiratory motion of the patient. Methods: A 4D computer tomography (CT) scan for a lung cancer patient treated with protons in our clinic was used to create a time dependent patient model using our in-house, MCNPX-based Monte Carlo system (“MC{sup 2}”). The beam line configurations for two passively scattered proton beams used in the actual treatment were extracted from the clinical treatment plan and a set of input files was created automatically using MC{sup 2}. A full MC simulation of the beam line was computed using MCNPX and a set of phase space files for each beam was collected at the distal surface of the range compensator. The particles from these phase space files were transported through the 10 voxelized patient models corresponding to the 10 phases of the breathing cycle in the 4DCT, using MCNPX and an accelerated (fast) MC code called “FDC”, developed by us and which is based on the track repeating algorithm. The accuracy of the fast algorithm was assessed by comparing the two time dependent dose distributions. Results: The error of less than 1% in 100% of the voxels in all phases of the breathing cycle was achieved using this method with a speedup of more than 1000 times. Conclusion: The proposed method, which uses full MC to simulate the beam line and the accelerated MC code FDC for the time consuming particle transport inside the complex, time dependent, geometry of the patient shows excellent accuracy together with an extraordinary speed.

  10. Four-dimensional magnetic resonance imaging for the determination of tumour movement and its evaluation using a dynamic porcine lung phantom

    Energy Technology Data Exchange (ETDEWEB)

    Remmert, G [Department of Medical Physics in Radiation Oncology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany); Biederer, J [Department of Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany); Lohberger, F [Department of Medical Physics in Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany); Fabel, M [Department of Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany); Hartmann, G H [Department of Medical Physics in Radiation Oncology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany)

    2007-09-21

    A method of four-dimensional (4D) magnetic resonance imaging (MRI) has been implemented and evaluated. It consists of retrospective sorting and slice stacking of two-dimensional (2D) images using an external signal for motion monitoring of the object to be imaged. The presented method aims to determine the tumour trajectories based on a signal that is appropriate for monitoring the movement of the target volume during radiotherapy such that the radiation delivery can be adapted to the movement. For evaluation of the 4D-MRI method, it has been applied to a dynamic lung phantom, which exhibits periodic respiratory movement of a porcine heart-lung explant with artificial pulmonary nodules. Anatomic changes of the lung phantom caused by respiratory motion have been quantified, revealing hysteresis. The results demonstrate the feasibility of the presented method of 4D-MRI. In particular, it enables the determination of trajectories of periodically moving objects with an uncertainty in the order of 1 mm. (note)

  11. Three-dimensional versus four-dimensional dose calculation for volumetric modulated arc therapy of hypofractionated treatments

    Energy Technology Data Exchange (ETDEWEB)

    Ehrbar, Stefanie; Lang, Stephanie; Stieb, Sonja; Riesterer, Oliver; Stark, Luisa Sabrina; Guckenberger, Matthias; Kloeck, Stephan [University Hospital Zuerich (Switzerland). Dept. of Radiation Oncology

    2016-05-01

    Purpose: Respiratory motion is a non-negligible source of uncertainty in radiotherapy. A common approach is to delineate the target volume in all respiratory phases (ITV) and to calculate a treatment plan using the average reconstruction of the four-dimensional computed tomography (4DCT) scans. In this study the extent of the interplay effect caused by interaction between dynamic dose delivery and respiratory tumor motion, as well as other motion effects were investigated. These effects are often ignored when the ITV concept is used. Methods and Materials: Nine previously treated patients with in ten abdominal or thoracic cancer lesions (3 liver, 3 adrenal glands and 4 lung lesions) were selected for this planning study. For all patients, phase-sorted respiration-correlated 4DCT scans were taken, and volumetric modulated arc therapy (VMAT) treatments were planned using the ITV concept. Margins from ITV to planning target volume (PTV) of 3-10 mm were used. Plans were optimized and dose distributions were calculated on the average reconstruction of the 4DCT. 4D dose distributions were calculated to evaluate motion effects, caused by the interference of dynamic treatment delivery with respiratory tumor motion and inhomogeneously planned target dose. These calculations were performed on the phase-sorted CT series with a respiration-correlated assignment of the treatment plan's monitor units (MU) to the respiration phases of the 4DCT. The 4D dose was accumulated with rigid as well as deformable registrations of the CT series and compared to the original 3D dose distribution. Maximum, minimum and mean doses to ITV and PTV, and maximum or mean doses to organs at risk (OAR), were compared after rigid accumulation. The dose variation in the gross tumor volume (GTV) was compared after deformable registration. Results: Using rigid registrations, variations in the investigated dose parameters between 3D and 4D dose calculations were found to be within -2.1% to 1.4% for

  12. On the Road Towards the Quantum Geometer's Universe: An Introduction to Four-Dimensional Supersymmetric Quantum Field Theories

    OpenAIRE

    Govaerts, Jan

    2004-01-01

    This brief set of notes presents a modest introduction to the basic features entering the construction of supersymmetric quantum field theories in four-dimensional Minkowski spacetime, building a bridge from similar lectures presented at a previous Workshop of this series, and reaching only at the doorstep of the full edifice of such theories.

  13. Randomized controlled trial to assess the effectiveness of a videotape about radiotherapy

    OpenAIRE

    Harrison, R; Dey, P.; Slevin, N J; Eardley, A; Gibbs, A; Cowan, R.; Logue, J P; Leidecker, V; Hopwood, P

    2001-01-01

    In a randomized controlled trial, the additional provision of information on videotape was no more effective than written information alone in reducing pre-treatment worry about radiotherapy. Images of surviving cancer patients, however, may provide further reassurance to patients once therapy is completed. © 2001 Cancer Research Campaign http://www.bjcancer.com

  14. Assessment of Olfactory Threshold in Patients Undergoing Radiotherapy for Head and Neck Malignancies

    Directory of Open Access Journals (Sweden)

    Mir Mohammad Jalali

    2014-10-01

    Conclusion:  Deterioration in olfactory threshold scores was found at 6 months after initiation of radiation therapy. Provided that these results are reproducible, an evaluation of olfactory functioning in patients with head and neck malignancies using in vivo dosimetry may be useful for determining the optimal dose for patients treated with conformal radiotherapy techniques while avoiding the side effects of radiation.

  15. Improved and robust detection of cell nuclei from four dimensional fluorescence images.

    Directory of Open Access Journals (Sweden)

    Md Khayrul Bashar

    Full Text Available Segmentation-free direct methods are quite efficient for automated nuclei extraction from high dimensional images. A few such methods do exist but most of them do not ensure algorithmic robustness to parameter and noise variations. In this research, we propose a method based on multiscale adaptive filtering for efficient and robust detection of nuclei centroids from four dimensional (4D fluorescence images. A temporal feedback mechanism is employed between the enhancement and the initial detection steps of a typical direct method. We estimate the minimum and maximum nuclei diameters from the previous frame and feed back them as filter lengths for multiscale enhancement of the current frame. A radial intensity-gradient function is optimized at positions of initial centroids to estimate all nuclei diameters. This procedure continues for processing subsequent images in the sequence. Above mechanism thus ensures proper enhancement by automated estimation of major parameters. This brings robustness and safeguards the system against additive noises and effects from wrong parameters. Later, the method and its single-scale variant are simplified for further reduction of parameters. The proposed method is then extended for nuclei volume segmentation. The same optimization technique is applied to final centroid positions of the enhanced image and the estimated diameters are projected onto the binary candidate regions to segment nuclei volumes.Our method is finally integrated with a simple sequential tracking approach to establish nuclear trajectories in the 4D space. Experimental evaluations with five image-sequences (each having 271 3D sequential images corresponding to five different mouse embryos show promising performances of our methods in terms of nuclear detection, segmentation, and tracking. A detail analysis with a sub-sequence of 101 3D images from an embryo reveals that the proposed method can improve the nuclei detection accuracy by 9% over

  16. GPU-based four-dimensional general-relativistic ray tracing

    Science.gov (United States)

    Kuchelmeister, Daniel; Müller, Thomas; Ament, Marco; Wunner, Günter; Weiskopf, Daniel

    2012-10-01

    This paper presents a new general-relativistic ray tracer that enables image synthesis on an interactive basis by exploiting the performance of graphics processing units (GPUs). The application is capable of visualizing the distortion of the stellar background as well as trajectories of moving astronomical objects orbiting a compact mass. Its source code includes metric definitions for the Schwarzschild and Kerr spacetimes that can be easily extended to other metric definitions, relying on its object-oriented design. The basic functionality features a scene description interface based on the scripting language Lua, real-time image output, and the ability to edit almost every parameter at runtime. The ray tracing code itself is implemented for parallel execution on the GPU using NVidia's Compute Unified Device Architecture (CUDA), which leads to performance improvement of an order of magnitude compared to a single CPU and makes the application competitive with small CPU cluster architectures. Program summary Program title: GpuRay4D Catalog identifier: AEMV_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEMV_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 73649 No. of bytes in distributed program, including test data, etc.: 1334251 Distribution format: tar.gz Programming language: C++, CUDA. Computer: Linux platforms with a NVidia CUDA enabled GPU (Compute Capability 1.3 or higher), C++ compiler, NVCC (The CUDA Compiler Driver). Operating system: Linux. RAM: 2 GB Classification: 1.5. External routines: OpenGL Utility Toolkit development files, NVidia CUDA Toolkit 3.2, Lua5.2 Nature of problem: Ray tracing in four-dimensional Lorentzian spacetimes. Solution method: Numerical integration of light rays, GPU-based parallel programming using CUDA, 3D

  17. High-quality four-dimensional cone-beam CT by deforming prior images

    Science.gov (United States)

    Wang, Jing; Gu, Xuejun

    2013-01-01

    Due to a limited number of projections at each phase, severe view aliasing artifacts are present in four-dimensional cone beam computed tomography (4D-CBCT) when reconstruction is performed using conventional algorithms. In this work, we aim to obtain high-quality 4D-CBCT of lung cancer patients in radiation therapy by deforming the planning CT. The deformation vector fields (DVF) to deform the planning CT are estimated through matching the forward projection of the deformed prior image and measured on-treatment CBCT projection. The estimation of the DVF is formulated as an unconstrained optimization problem, where the objective function to be minimized is the sum of the squared difference between the forward projection of the deformed planning CT and the measured 4D-CBCT projection. A nonlinear conjugate gradient method is used to solve the DVF. As the number of the variables in the DVF is much greater than the number of measurements, the solution to such a highly ill-posed problem is very sensitive to the initials during the optimization process. To improve the estimation accuracy of DVF, we proposed a new strategy to obtain better initials for the optimization. In this strategy, 4D-CBCT is first reconstructed by total variation minimization. Demons deformable registration is performed to register the planning CT and the 4D-CBCT reconstructed by total variation minimization. The resulted DVF from demons registration is then used as the initial parameters in the optimization process. A 4D nonuniform rotational B-spline-based cardiac-torso (NCAT) phantom and a patient 4D-CBCT are used to evaluate the algorithm. Image quality of 4D-CBCT is substantially improved by using the proposed strategy in both NCAT phantom and patient studies. The proposed method has the potential to improve the temporal resolution of 4D-CBCT. Improved 4D-CBCT can better characterize the motion of lung tumors and will be a valuable tool for image-guided adaptive radiation therapy.

  18. An assessment of PTV margin based on actual accumulated dose for prostate cancer radiotherapy

    Science.gov (United States)

    Wen, Ning; Kumarasiri, Akila; Nurushev, Teamour; Burmeister, Jay; Xing, Lei; Liu, Dezhi; Glide-Hurst, Carri; Kim, Jinkoo; Zhong, Hualiang; Movsas, Benjamin; Chetty, Indrin J.

    2013-11-01

    The purpose of this work is to present the results of a margin reduction study involving dosimetric and radiobiologic assessment of cumulative dose distributions, computed using an image guided adaptive radiotherapy based framework. Eight prostate cancer patients, treated with 7-9, 6 MV, intensity modulated radiation therapy (IMRT) fields, were included in this study. The workflow consists of cone beam CT (CBCT) based localization, deformable image registration of the CBCT to simulation CT image datasets (SIM-CT), dose reconstruction and dose accumulation on the SIM-CT, and plan evaluation using radiobiological models. For each patient, three IMRT plans were generated with different margins applied to the CTV. The PTV margin for the original plan was 10 mm and 6 mm at the prostate/anterior rectal wall interface (10/6 mm) and was reduced to: (a) 5/3 mm, and (b) 3 mm uniformly. The average percent reductions in predicted tumor control probability (TCP) in the accumulated (actual) plans in comparison to the original plans over eight patients were 0.4%, 0.7% and 11.0% with 10/6 mm, 5/3 mm and 3 mm uniform margin respectively. The mean increase in predicted normal tissue complication probability (NTCP) for grades 2/3 rectal bleeding for the actual plans in comparison to the static plans with margins of 10/6, 5/3 and 3 mm uniformly was 3.5%, 2.8% and 2.4% respectively. For the actual dose distributions, predicted NTCP for late rectal bleeding was reduced by 3.6% on average when the margin was reduced from 10/6 mm to 5/3 mm, and further reduced by 1.0% on average when the margin was reduced to 3 mm. The average reduction in complication free tumor control probability (P+) in the actual plans in comparison to the original plans with margins of 10/6, 5/3 and 3 mm was 3.7%, 2.4% and 13.6% correspondingly. The significant reduction of TCP and P+ in the actual plan with 3 mm margin came from one outlier, where individualizing patient treatment plans through margin adaptation

  19. A comparison of dosimetric variance for external-beam partial breast irradiation using three-dimensional and four-dimensional computed tomography

    Directory of Open Access Journals (Sweden)

    Guo B

    2016-03-01

    Full Text Available Bing Guo,1,2 Jian-Bin Li,2 Wei Wang,2 Min Xu,2 Yan-Kang Li,2,3 Tong-Hai Liu21School of Medicine and Life Sciences, University of Jinan-Shandong Academy of Medical Sciences, Jinan, Shandong Province, People’s Republic of China; 2Department of Radiation Oncology, Shandong Cancer Hospital & Institute, Jinan, Shandong Province, People’s Republic of China; 3School of Medicine, Shandong University, Jinan, Shandong Province, People’s Republic of ChinaPurpose: To investigate the potential dosimetric benefits from four-dimensional computed tomography (4DCT compared with three-dimensional computed tomography (3DCT in radiotherapy treatment planning for external-beam partial breast irradiation (EB-PBI.Patients and methods: 3DCT and 4DCT scan sets were acquired for 20 patients who underwent EB-PBI. The volume of the tumor bed (TB was determined based on seroma or surgical clips on 3DCT images (defined as TB3D and the end inhalation (EI and end exhalation (EE phases of 4DCT images (defined as TBEI and TBEE, respectively. The clinical target volume (CTV consisted of the TB plus a 1.0 cm margin. The planning target volume (PTV was the CTV plus 0.5 cm (defined as PTV3D, PTVEI, and PTVEE. For each patient, a conventional 3D conformal plan (3D-CRT was generated (defined as EB-PBI3D, EB-PBIEI, and EB-PBIEE.Results: The PTV3D, PTVEI, and PTVEE were similar (P=0.549, but the PTV coverage of EB-PBI3D was significantly less than that of EB-PBIEI or EB-PBIEE (P=0.001 and P=0.025, respectively. There were no significant differences in the homogeneity or conformity indexes between the three treatment plans (P=0.125 and P=0.536, respectively. The EB-PBI3D plan resulted in the largest organs at risk dose.Conclusion: There was a significant benefit for patients when using 3D-CRT based on 4DCT for EB-PBI with regard to reducing nontarget organ exposure. Respiratory motion did not affect the dosimetric distribution during free breathing, but might result in poor dose

  20. Four-dimensional cone beam CT reconstruction and enhancement using a temporal nonlocal means method

    International Nuclear Information System (INIS)

    Purpose: Four-dimensional cone beam computed tomography (4D-CBCT) has been developed to provide respiratory phase-resolved volumetric imaging in image guided radiation therapy. Conventionally, it is reconstructed by first sorting the x-ray projections into multiple respiratory phase bins according to a breathing signal extracted either from the projection images or some external surrogates, and then reconstructing a 3D CBCT image in each phase bin independently using FDK algorithm. This method requires adequate number of projections for each phase, which can be achieved using a low gantry rotation or multiple gantry rotations. Inadequate number of projections in each phase bin results in low quality 4D-CBCT images with obvious streaking artifacts. 4D-CBCT images at different breathing phases share a lot of redundant information, because they represent the same anatomy captured at slightly different temporal points. Taking this redundancy along the temporal dimension into account can in principle facilitate the reconstruction in the situation of inadequate number of projection images. In this work, the authors propose two novel 4D-CBCT algorithms: an iterative reconstruction algorithm and an enhancement algorithm, utilizing a temporal nonlocal means (TNLM) method. Methods: The authors define a TNLM energy term for a given set of 4D-CBCT images. Minimization of this term favors those 4D-CBCT images such that any anatomical features at one spatial point at one phase can be found in a nearby spatial point at neighboring phases. 4D-CBCT reconstruction is achieved by minimizing a total energy containing a data fidelity term and the TNLM energy term. As for the image enhancement, 4D-CBCT images generated by the FDK algorithm are enhanced by minimizing the TNLM function while keeping the enhanced images close to the FDK results. A forward–backward splitting algorithm and a Gauss–Jacobi iteration method are employed to solve the problems. The algorithms implementation

  1. A Novel Four-Dimensional Energy-Saving and Emission-Reduction System and Its Linear Feedback Control

    OpenAIRE

    Minggang Wang; Hua Xu

    2012-01-01

    This paper reports a new four-dimensional energy-saving and emission-reduction chaotic system. The system is obtained in accordance with the complicated relationship between energy saving and emission reduction, carbon emission, economic growth, and new energy development. The dynamics behavior of the system will be analyzed by means of Lyapunov exponents and equilibrium points. Linear feedback control methods are used to suppress chaos to unstable equilibrium. Numerical sim...

  2. Comparison of planning target volumes based on three-dimensional and four-dimensional CT imaging of thoracic esophageal cancer

    OpenAIRE

    Wang, Wei; LI, JIANBIN; Zhang, Yingjie; SHAO, QIAN; Xu, Min; Fan, Tingyong; Wang, Jinzhi

    2016-01-01

    Wei Wang, Jianbin Li, Yingjie Zhang, Qian Shao, Min Xu, Tingyong Fan, Jinzhi Wang Department of Radiation Oncology, Shandong Cancer Hospital Affiliated to Shandong University, Shandong Academy of Medical Sciences, Shandong, People’s Republic of China Background and purpose: To investigate the definition of planning target volumes (PTVs) based on four-dimensional computed tomography (4DCT) compared with conventional PTV definition and PTV definition using asymmetrical margins for t...

  3. Four-dimensional visualization of subpleural alveolar dynamics in vivo during uninterrupted mechanical ventilation of living swine

    OpenAIRE

    Namati, Eman; Warger, William C.; Unglert, Carolin I.; Eckert, Jocelyn E.; Hostens, Jeroen; Bouma, Brett E.; Tearney, Guillermo J.

    2013-01-01

    Pulmonary alveoli have been studied for many years, yet no unifying hypothesis exists for their dynamic mechanics during respiration due to their miniature size (100-300 μm dimater in humans) and constant motion, which prevent standard imaging techniques from visualizing four-dimensional dynamics of individual alveoli in vivo. Here we report a new platform to image the first layer of air-filled subpleural alveoli through the use of a lightweight optical frequency domain imaging (OFDI) probe t...

  4. Effect of tumor volume on the enhancement pattern of parathyroid adenoma on parathyroid four-dimensional CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Kyoung [Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Dongguk University Ilsan Hospital, Department of Radiology, Goyang-si (Korea, Republic of); Yun, Tae Jin; Kim, Ji-hoon; Kang, Koung Mi; Choi, Seung Hong; Sohn, Chul-Ho [Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Seoul National University Hospital, Department of Radiology, Jongno-gu, Seoul (Korea, Republic of); Lee, Kyu Eun; Kim, Su-jin [Seoul National University Hospital, Department of Surgery, Seoul (Korea, Republic of); Won, Jae-Kyung [Seoul National University Hospital, Department of Pathology, Seoul (Korea, Republic of)

    2016-05-15

    The purpose of this study is to assess the effect of tumor volume on the enhancement pattern of parathyroid adenoma (PTA) on four-dimensional computed tomography (4D-CT). We analyzed the enhancement patterns of PTA on four-phase 4D-CT in 44 patients. Dependency of the changes of Hounsfield unit values (ΔHU) on the tumor volumes and clinical characteristics was evaluated using linear regression analyses. In addition, an unpaired t test was used to compare ΔHU of PTAs between PTA volume ≥1 cm{sup 3} and <1 cm{sup 3}, thyroid gland, and lymph node. PTA volume based on CT was the strongest factor on the ΔHU{sub Pre} {sub to} {sub Arterial} and ΔHU{sub Arterial} {sub to} {sub Venous} and ΔHU{sub Arterial} {sub to} {sub Delayed} (R {sup 2} = 0.34, 0.25, and 0.32, respectively, P < 0.001 for both). PTA ≥1 cm {sup 3} had statistically significant greater enhancement between the unenhanced phase and the arterial phase than PTA <1 cm {sup 3} (mean values ± standard deviations (SDs) of ΔHU{sub Pre} {sub to} {sub Arterial}, 102.7 ± 33.7 and 57.5 ± 28.8, respectively, P < 0.001). PTA ≥1 cm {sup 3} showed an early washout pattern on the venous phase, whereas PTA <1 cm {sup 3} showed a progressive enhancement pattern on the venous phase (mean values ± SDs of ΔHU{sub Arterial} {sub to} {sub Venous}, -13.2 ± 31.6 and 14.4 ± 32.7, respectively; P = 0.009). The enhancement pattern of PTA on 4D-CT is variable with respect to PTA volume based on CT. Therefore, the enhancement pattern of PTA on 4D-CT requires careful interpretation concerning the tumor volume, especially in cases of PTA <1 cm {sup 3}. (orig.)

  5. Intensity-modulated radiotherapy, not 3D conformal, is the preferred technique for treating locally advanced lung cancer

    OpenAIRE

    Chang, Joe Y.

    2014-01-01

    When used to treat lung cancer, intensity-modulated radiotherapy (IMRT) can deliver higher dose to the targets and spare more critical organs in lung cancer than can 3D conformal radiotherapy (3DCRT). However, tumor-motion management and optimized radiotherapy planning based on four-dimensional computed tomography (4D CT) scanning are crucial to maximize the benefit of IMRT and to eliminate or minimize potential uncertainties. This article summarizes these strategies and reviews published fin...

  6. Dosimetric consequences of inter-fraction breathing-pattern variation on radiotherapy with personalized motion-assessed margins

    Science.gov (United States)

    Kavanagh, A.; McQuaid, D.; Evans, P.; Webb, S.; Guckenberger, M.

    2011-11-01

    The data from eight patients who had undergone stereotactic body radiotherapy were selected due to their 4D-CT planning scans showing that their tumours had respiratory induced motion trajectories of large amplitude (greater than 9 mm in cranio-caudal direction). Radiotherapy plans with personalized motion-assessed margins were generated for these eight patients. The margins were generated by inverse 4D planning on an eight-bin phase-sorted 4D-CT scan. The planning was done on an in-house software system with a non-rigid registration stage being completed using freely available software. The resultant plans were then recalculated on a 4D-CT scan taken later during the course of treatment. Simulated image-guided patient set-up was used to align the geometric centres of the tumour region and minimize any misalignment between the two reconstructions. In general, the variation in the patient breathing patterns was found to be very small. Consequently, the degradation of the mean dose to the tumour region was found to be around a few percent (<3%) and hence was not a large effect.

  7. A SEGMENTATION PROBLEM IN QUANTITATIVE ASSESSMENT OF ORGAN DISPOSITION IN RADIOTHERAPY

    Directory of Open Access Journals (Sweden)

    Giovanni Naldi

    2011-11-01

    Full Text Available Radiotherapeutic treatment of cancer is best conducted if the prescription dose is given to the tumor while surrounding normal tissues are maximally spared. With the aim to meet these requirements the complexity of radiotherapy techniques have steadily increased under a strong technological impulse, especially in the last decades. One problem involves the rate of the particular disposition of the structures of interest in a patient. Recently the authors (Tomatis et al., 2010; 2011 have proposed a computational approach in order to represent quantitatively the geometrical features of organs at risk, summarized in characteristics of distance, shape and orientation of such organs in respect to the target. A basic problem to solve before to compute the risk index, is the segmentation of the organs involved in the radiotherapy planning. Here we described a 3D segmentation method by using the clinical computed tomography (CT data of the patients. Our algorithm is based on different steps, a preprocessing phase where a nonlinear diffusion filter is applied; a level set based method for extract 2D countours; a postprocessing reconstruction of 3D volume from 2D segmented slices. Some comparisons with manually traced segmentation by clinical experts are provided.

  8. A four-dimensional lambda CDM-type cosmological model induced from higher dimensions using a kinematical constraint

    OpenAIRE

    Dereli, Tekin; Akarsu, Özgür

    2013-01-01

    arXiv:1201.4545v3 [gr-qc] 31 Mar 2013 A four-dimensional CDM-type cosmological model induced from higher dimensions using a kinematical constraint Özgür Akarsu, Tekin Dereli Department of Physics, Koç University, 34450 Sarıyer, İstanbul, Turkey Abstract A class of cosmological solutions of higher dimensional Einstein field equations with the energy-momentum tensor of a homogeneous, isotropic fluid as the source are considered with an anisotropic metric that includes t...

  9. Four-dimensional anti-de Sitter black holes from a three-dimensional perspective Full complexity

    CERN Document Server

    Zanchin, V T; Lemos, J P S

    2002-01-01

    The dimensional reduction of black hole solutions in four-dimensional (4D) general relativity is performed and new 3D black hole solutions are obtained. Considering a 4D spacetime with one spacelike Killing vector, it is possible to split the Einstein-Hilbert-Maxwell action with a cosmological term in terms of 3D quantities. Definitions of quasilocal mass and charges in 3D spacetimes are reviewed. The analysis is then particularized to the toroidal charged rotating anti-de Sitter black hole. The reinterpretation of the fields and charges in terms of a three-dimensional point of view is given in each case, and the causal structure analyzed.

  10. Impaired DNA repair as assessed by the ''comet'' assay in patients developing thyroid carcinoma after radiotherapy

    International Nuclear Information System (INIS)

    A defective cellular response to DNA lesions induced be genotoxic agents may be associated to an increased cancer proneness. This has been clearly identified in some rare but extensively studied genetic diseases such as xeroderma pigmentosum (XP), ataxia telangiectasia (AT) and Fanconi anemia (FA). In practical oncology, most patients receive genotoxic therapeutic agents and the presence of so far unidentified sensitive genotypes could account for an increased susceptibility to cancer in a subgroup of exposed patients. The thyroid gland of children is especially sensitive to the carcinogenic effect of ionizing radiation. Evidence for risk is reported even at doses as low as 0.1 Gy, and the excess relative risk to develop a thyroid tumor following a radiation dose of 1 Gy in childhood is of 7.7 [l]. In order to determine if a defect in repair of DNA strand breaks could be involved, as an early step, in the development of secondary thyroid tumors after radiotherapy, we examined, using the alkaline single cell gel electrophoresis assay (SCGE or 'comet'), the response to in vitro γ-rays exposure of lymphocytes of a small group of patients who developed thyroid carcinoma after radiotherapy for a primary tumor. Because of its practical advantages, the alkaline comet assay offers the opportunity to question the role of DNA strand beaks rejoining capacity of the individual in the radiation induced carcinogenesis of thyroid tumors. This preliminary study of a small group of patients with therapeutic irradiation at childhood for a primary tumor indicates that, at the time of blood sampling, lymphocytes of some of these patients demonstrated reduced rejoining capacity. These results suggest that the comet assay might help to distinguish a subgroup of individuals at risk for radiation induced genomic instability and encourage further investigation. (authors)

  11. Assessment of pulmonary toxicities in breast cancer patients undergoing treatment with anthracycline and taxane based chemotherapy and radiotherapy- a prospective study

    Directory of Open Access Journals (Sweden)

    Aramita Saha

    2013-12-01

    Full Text Available Background: Anthracycline based regiments and/or taxanes and adjuvant radiotherapy; the main modalities of treatment for breast cancers are associated with deterioration of pulmonary functions and progressive pulmonary toxicities. Aim: Assessment of pulmonary toxicities and impact on pulmonary functions mainly in terms of decline of forced vital capacity (FVC and the ratio of forced expiratory volume (FEV in 1 Second and FEV1/FVC ratio with different treatment times and follow ups in carcinoma breast patients receiving anthracycline and/or taxane based chemotherapy and radiotherapy. Materials and methods: A prospective single institutional cohort study was performed with 58 breast cancer patients between January 2011 to July 2012 who received either anthracycline based (37 patients received 6 cycles FAC= 5 FU, Adriamycin, Cyclophosphamide regime and radiotherapy or anthracycline and taxane based chemotherapy (21 patients received 4cycles AC= Adriamycin, Cyclophosphamide; followed by 4 cycles of T=Taxane and radiotherapy. Assessment of pulmonary symptoms and signs, chest x-ray and pulmonary function tests were performed at baseline, midcycle, at end of chemotherapy, at end radiotherapy, at 1 and 6 months follow ups and compared. By means of a two-way analysis of variance (ANOVA model, the course of lung parameters across the time points was compared. Results and Conclusion: Analysis of mean forced vital capacities at different points of study times showed definitive declining pattern, which is at statistically significant level at the end of 6th month of follow up (p=0.032 .The FEV1/FVC ratio (in percentage also revealed a definite decreasing pattern over different treatment times and at statistically significant level at 6th month follow up with p value 0.003. Separate analysis of mean FEV1/FVC ratios over time in anthracycline based chemotherapy and radiotherapy group as well as anthracycline and taxane based chemotherapy and radiotherapy group

  12. An explicit four-dimensional variational data assimilation method based on the proper orthogonal decomposition: Theoretics and evaluation

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The proper orthogonal decomposition (POD) method is used to construct a set of basis functions for spanning the ensemble of data in a certain least squares optimal sense. Compared with the singular value decomposition (SVD), the POD basis functions can capture more energy in the forecast ensemble space and can represent its spatial structure and temporal evolution more effectively. After the analysis variables are expressed by a truncated expansion of the POD basis vectors in the ensemble space, the control variables appear explicitly in the cost function, so that the adjoint model, which is used to de-rive the gradient of the cost function with respect to the control variables, is no longer needed. The application of this new technique significantly simplifies the data assimilation process. Several as-similation experiments show that this POD-based explicit four-dimensional variational data assimila-tion method performs much better than the usual ensemble Kalman filter method on both enhancing the assimilation precision and reducing the computation cost. It is also better than the SVD-based ex-plicit four-dimensional assimilation method, especially when the forecast model is not perfect and the forecast error comes from both the noise of the initial filed and the uncertainty of the forecast model.

  13. Motion of particles on a Four-Dimensional Asymptotically AdS Black Hole with Scalar Hair

    CERN Document Server

    Gonzalez, P A; Vasquez, Yerko

    2015-01-01

    Motivated by black hole solutions with matter fields outside their horizon, we study the effect of these matter fields in the motion of massless and massive particles. We consider as background a four-dimensional asymptotically AdS black hole with scalar hair. The geodesics are studied numerically and we discuss about the differences in the motion of particles between the four-dimensional asymptotically AdS black holes with scalar hair and their no-hair limit, that is, Schwarzschild AdS black holes. Mainly, we found that there are bounded orbits like planetary orbits in this background. However, the periods associated to circular orbits are modified by the presence of the scalar hair. Besides, we found that some classical tests such as perihelion precession, deflection of light and gravitational time delay have the standard value of general relativity plus a correction term coming from the cosmological constant and the scalar hair. Finally, we found a specific value of the parameter associated to the scalar h...

  14. Motion of particles on a four-dimensional asymptotically AdS black hole with scalar hair

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, P.A.; Olivares, Marco [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)

    2015-10-15

    Motivated by black hole solutions with matter fields outside their horizon, we study the effect of these matter fields on the motion of massless and massive particles. We consider as background a four-dimensional asymptotically AdS black hole with scalar hair. The geodesics are studied numerically and we discuss the differences in the motion of particles between the four-dimensional asymptotically AdS black holes with scalar hair and their no-hair limit, that is, Schwarzschild AdS black holes. Mainly, we found that there are bounded orbits like planetary orbits in this background. However, the periods associated to circular orbits are modified by the presence of the scalar hair. Besides, we found that some classical tests such as perihelion precession, deflection of light, and gravitational time delay have the standard value of general relativity plus a correction term coming from the cosmological constant and the scalar hair. Finally, we found a specific value of the parameter associated to the scalar hair, in order to explain the discrepancy between the theory and the observations, for the perihelion precession of Mercury and light deflection. (orig.)

  15. Analysis on the computability over the efficient utilization problem of the four-dimensional space-time

    CERN Document Server

    Huang, Wenqi

    2011-01-01

    This paper formally proposes a problem about the efficient utilization of the four dimensional space-time. Given a cuboid container, a finite number of rigid cuboid items, and the time length that each item should be continuous baked in the container, the problem asks to arrange the starting time for each item being placed into the container and to arrange the position and orientation for each item at each instant during its continuous baking period such that the total time length the container be utilized is as short as possible. Here all side dimensions of the container and of the items are positive real numbers arbitrarily given. Differs from the classical packing problems, the position and orientation of each item in the container could be changed over time. Therefore, according to above mathematical model, the four-dimensional space-time can be utilized more truly and more fully. This paper then proves that there exists an exact algorithm that could solve the problem by finite operations, so we say this ...

  16. Modeling of the World Ocean circulation with the four-dimensional assimilation of temperature and salinity fields

    Science.gov (United States)

    Marchuk, G. I.; Zalesny, V. B.

    2012-02-01

    The problem of modeling the World Ocean circulation with the four-dimensional assimilation of temperature and salinity fields is considered. A mathematical model of the ocean general circulation and a numerical algorithm for its solution are formulated. The model equations are written in a σ coordinate system on the sphere with the North Pole shifted to the point of the continent (60° E, 60.5° N). The model has a flexible numerical structure and consists of two parts: the forward prognostic model and its adjoint analog. The numerical algorithm for solving the forward and adjoint problems is based on the method of multicomponent splitting. This method includes splitting with respect to physical processes and geometric coordinates. Three series of numerical experiments are performed: (1) a test solution to the problem of the four-dimensional variational assimilation, (2) modeling of the World Ocean circulation with the variational assimilation of climatic temperature and salinity fields, and (3) modeling of the World Ocean circulation with the variational assimilation of climatic temperature and salinity fields and the data of Argo buoys. The results of calculations demonstrate the expediency of using the model of World Ocean circulation with the procedure of assimilating observational data for a description of the general structure of thermohaline fields.

  17. Phantom-based evaluations of two binning algorithms for four-dimensional CT reconstruction in lung cancer radiation therapy

    Institute of Scientific and Technical Information of China (English)

    Fuli Zhang; Huayong Jiang; Weidong Xu; Yadi Wang ; Qingzhi Liu; Na Lu; Diandian Chen; Bo Yao

    2014-01-01

    Objective: The purpose of this study was to evaluate the performance of the phase-binning algorithm and am-plitude-binning algorithm for four-dimensional computed tomography (4DCT) reconstruction in lung cancer radiation therapy. Methods: Quasar phantom data were used for evaluation.Aphantom of known geometry was mounted on a four-dimensional (4D) motion platform programmed with twelve respiratory waves (twelve lung patients trajectories) and scanned with a Philips Bril iance Big bore 16-slice CT simulator. The 4DCT images were reconstructed using both phase- and amplitude-binning algorithms. Internal target volumes (ITVs) of the phase- and amplitude-binned image sets were compared by evaluation of shape and volume distortions. Results: The phantom experiments il ustrated that, as expected, maximum inhalation occurred at the 0% amplitude and maximum exhalation occurred at the 50% amplitude of the amplitude-binned 4DCT image sets. The amplitude-binned algorithm rendered smal er ITV than the phase-binning algorithm. Conclusion: The amplitude-binning algorithm for 4DCT reconstruction may have a potential advantage in reducing the margin and protecting normal lung tissue from unnecessary irradiation.

  18. Validation of four-dimensional ultrasound for targeting in minimally-invasive beating-heart surgery

    Science.gov (United States)

    Pace, Danielle F.; Wiles, Andrew D.; Moore, John; Wedlake, Chris; Gobbi, David G.; Peters, Terry M.

    2009-02-01

    Ultrasound is garnering significant interest as an imaging modality for surgical guidance, due to its affordability, real-time temporal resolution and ease of integration into the operating room. Minimally-invasive intracardiac surgery performed on the beating-heart prevents direct vision of the surgical target, and procedures such as mitral valve replacement and atrial septal defect closure would benefit from intraoperative ultrasound imaging. We propose that placing 4D ultrasound within an augmented reality environment, along with a patient-specific cardiac model and virtual representations of tracked surgical tools, will create a visually intuitive platform with sufficient image information to safely and accurately repair tissue within the beating heart. However, the quality of the imaging parameters, spatial calibration, temporal calibration and ECG-gating must be well characterized before any 4D ultrasound system can be used clinically to guide the treatment of moving structures. In this paper, we describe a comprehensive accuracy assessment framework that can be used to evaluate the performance of 4D ultrasound systems while imaging moving targets. We image a dynamic phantom that is comprised of a simple robot and a tracked phantom to which point-source, distance and spherical objects of known construction can be attached. We also follow our protocol to evaluate 4D ultrasound images generated in real-time by reconstructing ECG-gated 2D ultrasound images acquired from a tracked multiplanar transesophageal probe. Likewise, our evaluation framework allows any type of 4D ultrasound to be quantitatively assessed.

  19. A brief survey of the renormalizability of four dimensional gravity for generalized Kodama states

    CERN Document Server

    Ita, Eyo Eyo

    2008-01-01

    We continue the line of research from previous works in assessing the suitability of the pure Kodama state both as a ground state for the generalized Kodama states, as well as characteristic of a good semiclassical limit of general relativity. We briefly introduce the quantum theory of fluctuations about DeSitter spacetime, which enables one to examine some perturbative aspects of the state. Additionally, we also motivate the concept of the cubic tree network, which enables one to view the generalized Kodama states in compact form as a nonlinear transformation of the pure Kodama states parametrized by the matter content of the proper classical limit. It is hoped that this work constitutes a first step in addressing the nonperturbative renormalizability of general relativity in Ashtekar variables. Remaining issues to address, including the analysis of specific matter models, include finiteness and normalizability of the generalized Kodama state as well as reality conditions on the Ashtekar variables, which we ...

  20. Application of four dimensional matrix for thermal analysis of Slovak transit gas pipeline by program FENIX

    Science.gov (United States)

    Széplaky, Dávid; Varga, Augustín

    2016-06-01

    The contribution describes the principle of the FENIX program operation, which was designed to determine the temperature field of the transit pipeline for the transportation of natural gas. The program itself consists of several modules which are reciprocally linked. The basis of the program is the elementary balance method by means of which the unsteady heat transfer is assigned in several layers in different directions. The first step was to assess both the pressure and temperature of the natural gas mode, the second step is to determine the heat transfer through the walls of the pipes, and the last one is to determine the distribution of the temperature field in the surroundings of the pipeline.

  1. Investigating the Impact on Modeled Ozone Concentrations Using Meteorological Fields From WRF With and Updated Four-Dimensional Data Assimilation Approach”

    Science.gov (United States)

    The four-dimensional data assimilation (FDDA) technique in the Weather Research and Forecasting (WRF) meteorological model has recently undergone an important update from the original version. Previous evaluation results have demonstrated that the updated FDDA approach in WRF pr...

  2. A four-dimensional validation of a coupled physical-biological model of the Arabian Sea

    Science.gov (United States)

    Hood, Raleigh R.; Kohler, Kevin E.; McCreary, Julian P.; Smith, Sharon L.

    2003-11-01

    In this paper, we use a coupled biological/physical model to synthesize and understand observations taken during the US JGOFS Arabian Sea Process Study (ASPS). Its physical component is a variable-density, 4 1/2-layer model; its biological component consists of a set of advective-diffusive equations in each layer that determine nitrogen concentrations in four compartments, namely, nutrients, phytoplankton, zooplankton, and detritus. Solutions are compared to time series and cruise sections from the ASPS data set, including observations of mixed-layer thickness, chlorophyll concentrations, inorganic nitrogen concentrations, particulate nitrogen export flux, zooplankton biomass, and primary production. Through these comparisons, we adjust model parameters to obtain a "best-fit" main-run solution, identify key biological and physical processes, and assess model strengths and weaknesses. Substantial improvements in the model/data comparison are obtained by: (1) adjusting the turbulence-production coefficients in the mixed-layer model to thin the mixed layer; (2) increasing the detrital sinking and remineralization rates to improve the timing and amplitude of the model's export flux; and (3) introducing a parameterization of particle aggregation to lower phytoplankton concentrations in coastal upwelling regions. With these adjustments, the model captures many key aspects of the observed physical and biogeochemical variability in offshore waters, including the near-surface DIN and phytoplankton P concentrations, mesozooplankton biomass, and primary production. Nevertheless, there are still significant model/data discrepancies of P for most of the cruises. Most of them can be attributed to forcing or process errors in the physical model: inaccurate mixed-layer thicknesses, lack of mesoscale eddies and filaments, and differences in the timing and spatial extent of coastal upwelling. Relatively few are clearly related to the simplicity of the biological model, the model

  3. Quantitative dosimetric assessment for effect of gold nanoparticles as contrast media on radiotherapy planning

    International Nuclear Information System (INIS)

    In CT planning for radiation therapy, patients may be asked to have a medical procedure of contrast agent (CA) administration as required by their physicians. CA media improve quality of CT images and assist radiation oncologists in delineation of the target or organs with accuracy. However, dosimetric discrepancy may occur between scenarios in which CA media are present in CT planning and absent in treatment delivery. In recent preclinical experiments of small animals, gold nanoparticles (AuNPs) have been identified as an excellent contrast material of x-ray imaging. In this work, we quantitatively evaluate the effect of AuNPs to be used as a potential material of contrast enhancement in radiotherapy planning with an analytical phantom and clinical case. Conray 60, an iodine-based product for contrast enhancement in clinical uses, is included as a comparison. Other additional variables such as different concentrations of CA media, radiation delivery techniques and dose calculation algorithms are included. We consider 1-field AP, 4-field box, 7-field intensity modulated radiation therapy (IMRT) and a recent technique of volumetric modulated arc therapy (VMAT). CA media of AuNPs (Conray 60) with concentrations of 10%, 20%, 30%, 40% and 50% containing 28.2, 56.4, 84.6, 112.8 and 141.0 mg of gold (iodine) per mL were prepared prior to CT scanning. A virtual phantom with a target where nanoparticle media are loaded and clinical case of gastric lymphoma in which the Conray 60 media were given to the patient prior to the CT planning are included for the study. Compared to Conray 60 media with concentration of 10%/50%, Hounsfield units for AuNP media of 10%/50% are 322/1608 higher due to the fact that atomic number of Au (Z=79) is larger than I (Z=53). In consequence, dosimetric discrepancy of AuNPs is magnified between presence and absence of contrast media. It was found in the phantom study that percent dose differences between presence and absence of CA media may be

  4. Unified registration framework for cumulative dose assessment in cervical cancer across external beam radiotherapy and brachytherapy

    Science.gov (United States)

    Roy, Sharmili; Totman, John J.; Choo, Bok A.

    2016-03-01

    Dose accumulation across External Beam Radiotherapy (EBRT) and Brachytherapy (BT) treatment fractions in cervical cancer is extremely challenging due to structural dissimilarities and large inter-fractional anatomic deformations between the EBRT and BT images. The brachytherapy applicator and the bladder balloon, present only in the BT images, introduce missing structural correspondences for the underlying registration problem. Complex anatomical deformations caused by the applicator and the balloon, different rectum and bladder filling and tumor shrinkage compound the registration difficulties. Conventional free-form registration methods struggle to handle such topological differences. In this paper, we propose a registration pipeline that first transforms the original images to their distance maps based on segmentations of critical organs and then performs non-linear registration of the distance maps. The resulting dense deformation field is then used to transform the original anatomical image. The registration accuracy is evaluated on 27 image pairs from stage 2B-4A cervical cancer patients. The algorithm reaches a Hausdorff distance of close to 0:5 mm for the uterus, 2:2 mm for the bladder and 1:7 mm for the rectum when applied to (EBRT,BT) pairs, taken at time points more than three months apart. This generalized model-free framework can be used to register any combination of EBRT and BT images as opposed to methods in the literature that are tuned for either only (BT,BT) pair, or only (EBRT,EBRT) pair or only (BT,EBRT) pair. A unified framework for 3D dose accumulation across multiple EBRT and BT fractions is proposed to facilitate adaptive personalized radiation therapy.

  5. Preclinical dynamic 18F-FDG PET - tumor characterization and radiotherapy response assessment by kinetic compartment analysis

    Energy Technology Data Exchange (ETDEWEB)

    Roee, Kathrine; Aleksandersen, Thomas B.; Nilsen, Line B.; Hong Qu; Ree, Anne H.; Malinen, Eirik (Univ. of Oslo, Oslo (Norway)), E-mail: Kathrine.Roe@rr-research.no; Kristian, Alexandr (Dept. of Tumor Biology, Inst. for Cancer Research, The Norwegian Radium Hospital, Oslo Univ. Hospital, Oslo (Norway)); Seierstad, Therese (Dept. of Radiation Biology, Inst. for Cancer Research, The Norwegian Radium Hospital, Oslo Univ. Hospital, Oslo (Norway)); Olsen, Dag R. (Univ. of Bergen, Bergen (Norway))

    2010-10-15

    Background. Non-invasive visualization of tumor biological and molecular processes of importance to diagnosis and treatment response is likely to be critical in individualized cancer therapy. Since conventional static 18F-FDG PET with calculation of the semi-quantitative parameter standardized uptake value (SUV) may be subject to many sources of variability, we here present an approach of quantifying the 18F-FDG uptake by analytic two-tissue compartment modeling, extracting kinetic tumor parameters from dynamic 18F-FDG PET. Further, we evaluate the potential of such parameters in radiotherapy response assessment. Material and methods. Male, athymic mice with prostate carcinoma xenografts were subjected to dynamic PET either untreated (n=8) or 24 h post-irradiation (7.5 Gy single dose, n=8). After 10 h of fasting, intravenous bolus injections of 10-15 MBq 18F-FDG were administered and a 1 h dynamic PET scan was performed. 4D emission data were reconstructed using OSEM-MAP, before remote post-processing. Individual arterial input functions were extracted from the image series. Subsequently, tumor 18F-FDG uptake was fitted voxel-by-voxel to a compartment model, producing kinetic parameter maps. Results. The kinetic model separated the 18F-FDG uptake into free and bound tracer and quantified three parameters; forward tracer diffusion (k1), backward tracer diffusion (k2), and rate of 18F-FDG phosphorylation, i.e. the glucose metabolism (k3). The fitted kinetic model gave a goodness of fit (r2) to the observed data ranging from 0.91 to 0.99, and produced parametrical images of all tumors included in the study. Untreated tumors showed homogeneous intra-group median values of all three parameters (k1, k2 and k3), whereas the parameters significantly increased in the tumors irradiated 24 h prior to 18F-FDG PET. Conclusions. This study demonstrates the feasibility of a two-tissue compartment kinetic analysis of dynamic 18F-FDG PET images. If validated, extracted parametrical

  6. Adjoint free four-dimensional variational data assimilation for a storm surge model of the German North Sea

    Science.gov (United States)

    Zheng, Xiangyang; Mayerle, Roberto; Xing, Qianguo; Fernández Jaramillo, José Manuel

    2016-06-01

    In this paper, a data assimilation scheme based on the adjoint free Four-Dimensional Variational(4DVar) method is applied to an existing storm surge model of the German North Sea. To avoid the need of an adjoint model, an ensemble-like method to explicitly represent the linear tangent equation is adopted. Results of twin experiments have shown that the method is able to recover the contaminated low dimension model parameters to their true values. The data assimilation scheme was applied to a severe storm surge event which occurred in the North Sea in December 5, 2013. By adjusting wind drag coefficient, the predictive ability of the model increased significantly. Preliminary experiments have shown that an increase in the predictive ability is attained by narrowing the data assimilation time window.

  7. Four-dimensional symmetry from a broad viewpoint. II Invariant distribution of quantized field oscillators and questions on infinities

    Science.gov (United States)

    Hsu, J. P.

    1983-01-01

    The foundation of the quantum field theory is changed by introducing a new universal probability principle into field operators: one single inherent and invariant probability distribution P(/k/) is postulated for boson and fermion field oscillators. This can be accomplished only when one treats the four-dimensional symmetry from a broad viewpoint. Special relativity is too restrictive to allow such a universal probability principle. A radical length, R, appears in physics through the probability distribution P(/k/). The force between two point particles vanishes when their relative distance tends to zero. This appears to be a general property for all forces and resembles the property of asymptotic freedom. The usual infinities in vacuum fluctuations and in local interactions, however complicated they may be, are all removed from quantum field theories. In appendix A a simple finite and unitary theory of unified electroweak interactions is discussed without assuming Higgs scalar bosons.

  8. Development by three-dimensional approaches and four-dimensional imaging: to the knowledge frontier and beyond.

    Science.gov (United States)

    Carneiro, Katia; de Brito, Jose M; Rossi, Maria I D

    2015-03-01

    Many advances have been taken on elucidating embryonic development and tissue homeostasis and repair by the use of experimental strategies that preserve the three-dimensional (3D) organization and allow quantitative analysis of images over time (four-dimensional). Ranging from the understanding about the relationship between blastomeres and the events that take place during gastrulation by the use of time-lapse imaging through 3D cultures that mimic organogenesis, the advances in this area are of critical value. The studies on embryonic development without disrupting the original architecture and the development of 3D organoid cultures pave a new avenue for unprecedented experimental advances that will positively impact the emergence of new treatments applying regenerative principles for both tissue repair and organ transplant. PMID:25789860

  9. Testing a four-dimensional variational data assimilation method using an improved intermediate coupled model for ENSO analysis and prediction

    Science.gov (United States)

    Gao, Chuan; Wu, Xinrong; Zhang, Rong-Hua

    2016-07-01

    A four-dimensional variational (4D-Var) data assimilation method is implemented in an improved intermediate coupled model (ICM) of the tropical Pacific. A twin experiment is designed to evaluate the impact of the 4D-Var data assimilation algorithm on ENSO analysis and prediction based on the ICM. The model error is assumed to arise only from the parameter uncertainty. The "observation" of the SST anomaly, which is sampled from a "truth" model simulation that takes default parameter values and has Gaussian noise added, is directly assimilated into the assimilation model with its parameters set erroneously. Results show that 4D-Var effectively reduces the error of ENSO analysis and therefore improves the prediction skill of ENSO events compared with the non-assimilation case. These results provide a promising way for the ICM to achieve better real-time ENSO prediction.

  10. Measuring working memory is all fun and games: a four-dimensional spatial game predicts cognitive task performance.

    Science.gov (United States)

    Atkins, Sharona M; Sprenger, Amber M; Colflesh, Gregory J H; Briner, Timothy L; Buchanan, Jacob B; Chavis, Sydnee E; Chen, Sy-Yu; Iannuzzi, Gregory L; Kashtelyan, Vadim; Dowling, Eamon; Harbison, J Isaiah; Bolger, Donald J; Bunting, Michael F; Dougherty, Michael R

    2014-01-01

    We developed a novel four-dimensional spatial task called Shapebuilder and used it to predict performance on a wide variety of cognitive tasks. In six experiments, we illustrate that Shapebuilder: (1) Loads on a common factor with complex working memory (WM) span tasks and that it predicts performance on quantitative reasoning tasks and Ravens Progressive Matrices (Experiment 1), (2) Correlates well with traditional complex WM span tasks (Experiment 2), predicts performance on the conditional go/no go task (Experiment 3) and N-back (Experiment 4), and showed weak or nonsignificant correlations with the Attention Networks Task (Experiment 5), and task switching (Experiment 6). Shapebuilder shows that it exhibits minimal skew and kurtosis, and shows good reliability. We argue that Shapebuilder has many advantages over existing measures of WM, including the fact that it is largely language independent, is not prone to ceiling effects, and take less than 6 min to complete on average.

  11. Development of an ultra-high-speed scanning neutron tomography system for high-quality and four-dimensional visualizations

    International Nuclear Information System (INIS)

    A new neutron tomography imaging system was developed in order to realize high-quality three-dimensional (3D) and four-dimensional (4D) visualizations by fusing the high-frame-rate neutron radiography and computed tomography (CT) techniques. The fundamental idea is that the object is revolved with high rotating speed and the neutron radiography images are recorded with a high-speed video camera and an image intensifier, and then the consecutive images are processed by a 3D CT technique. The 4D dynamic images of the sand flow in the sandglasses could be visualized clearly. This new technique has also an advantage in that it can reduce radio-activation of the object materials remarkably.

  12. Determination of critical linear lattice size for the four dimensional Ising model on the Creutz cellular automaton

    Science.gov (United States)

    Kizilirmak, Ganimet Mülazımoğlu

    2015-12-01

    The four-dimensional Ising model is simulated on the Creutz cellular automaton (CCA) near the infinite-lattice critical temperature for the lattice with the linear dimension 4 ⩽ L ⩽ 22. The temperature dependence of Binder parameter ( g L) are analyzed for the lattice with the linear dimension 4 ⩽ L ⩽ 22. In this study conducted highly detailed, two different types of behavior were determined as a result of varying linear lattice dimension. The infinite lattice critical temperatures are obtained to be T c = 6.6845 ± 0.0005 in interval 4 ⩽ L ⩽ 12 and T c = 6.6807 ± 0.0024 in interval 14 ⩽ L ⩽ 22. The finite and infinite lattice critical exponents for the order parameter, the magnetic susceptibility and the specific heat are computed from the results of simulations by using finite-size scaling relations. Critical linear lattice size have been identified as L = 14.

  13. Measuring working memory is all fun and games: a four-dimensional spatial game predicts cognitive task performance.

    Science.gov (United States)

    Atkins, Sharona M; Sprenger, Amber M; Colflesh, Gregory J H; Briner, Timothy L; Buchanan, Jacob B; Chavis, Sydnee E; Chen, Sy-Yu; Iannuzzi, Gregory L; Kashtelyan, Vadim; Dowling, Eamon; Harbison, J Isaiah; Bolger, Donald J; Bunting, Michael F; Dougherty, Michael R

    2014-01-01

    We developed a novel four-dimensional spatial task called Shapebuilder and used it to predict performance on a wide variety of cognitive tasks. In six experiments, we illustrate that Shapebuilder: (1) Loads on a common factor with complex working memory (WM) span tasks and that it predicts performance on quantitative reasoning tasks and Ravens Progressive Matrices (Experiment 1), (2) Correlates well with traditional complex WM span tasks (Experiment 2), predicts performance on the conditional go/no go task (Experiment 3) and N-back (Experiment 4), and showed weak or nonsignificant correlations with the Attention Networks Task (Experiment 5), and task switching (Experiment 6). Shapebuilder shows that it exhibits minimal skew and kurtosis, and shows good reliability. We argue that Shapebuilder has many advantages over existing measures of WM, including the fact that it is largely language independent, is not prone to ceiling effects, and take less than 6 min to complete on average. PMID:24962121

  14. Adjoint free four-dimensional variational data assimilation for a storm surge model of the German North Sea

    Science.gov (United States)

    Zheng, Xiangyang; Mayerle, Roberto; Xing, Qianguo; Fernández Jaramillo, José Manuel

    2016-08-01

    In this paper, a data assimilation scheme based on the adjoint free Four-Dimensional Variational(4DVar) method is applied to an existing storm surge model of the German North Sea. To avoid the need of an adjoint model, an ensemble-like method to explicitly represent the linear tangent equation is adopted. Results of twin experiments have shown that the method is able to recover the contaminated low dimension model parameters to their true values. The data assimilation scheme was applied to a severe storm surge event which occurred in the North Sea in December 5, 2013. By adjusting wind drag coefficient, the predictive ability of the model increased significantly. Preliminary experiments have shown that an increase in the predictive ability is attained by narrowing the data assimilation time window.

  15. Investigation of four-dimensional computed tomography-based pulmonary ventilation imaging in patients with emphysematous lung regions

    Science.gov (United States)

    Yamamoto, Tokihiro; Kabus, Sven; Klinder, Tobias; Lorenz, Cristian; von Berg, Jens; Blaffert, Thomas; Loo, Billy W., Jr.; Keall, Paul J.

    2011-04-01

    A pulmonary ventilation imaging technique based on four-dimensional (4D) computed tomography (CT) has advantages over existing techniques. However, physiologically accurate 4D-CT ventilation imaging has not been achieved in patients. The purpose of this study was to evaluate 4D-CT ventilation imaging by correlating ventilation with emphysema. Emphysematous lung regions are less ventilated and can be used as surrogates for low ventilation. We tested the hypothesis: 4D-CT ventilation in emphysematous lung regions is significantly lower than in non-emphysematous regions. Four-dimensional CT ventilation images were created for 12 patients with emphysematous lung regions as observed on CT, using a total of four combinations of two deformable image registration (DIR) algorithms: surface-based (DIRsur) and volumetric (DIRvol), and two metrics: Hounsfield unit (HU) change (VHU) and Jacobian determinant of deformation (VJac), yielding four ventilation image sets per patient. Emphysematous lung regions were detected by density masking. We tested our hypothesis using the one-tailed t-test. Visually, different DIR algorithms and metrics yielded spatially variant 4D-CT ventilation images. The mean ventilation values in emphysematous lung regions were consistently lower than in non-emphysematous regions for all the combinations of DIR algorithms and metrics. VHU resulted in statistically significant differences for both DIRsur (0.14 ± 0.14 versus 0.29 ± 0.16, p = 0.01) and DIRvol (0.13 ± 0.13 versus 0.27 ± 0.15, p ventilation and emphysema, which indicates the potential for HU-based 4D-CT ventilation imaging to achieve high physiologic accuracy. A further study is needed to confirm these results.

  16. Patient safety in external beam radiotherapy – Guidelines on risk assessment and analysis of adverse error-events and near misses: Introducing the ACCIRAD project

    International Nuclear Information System (INIS)

    In 2011 the European Commission launched a tender to develop guidelines for risk analysis of accidental and unintended exposures in external beam radiotherapy. This tender was awarded to a consortium of 6 institutions, including the ESTRO, in late 2011. The project, denominated “ACCIRAD”, recently finished the data collection phase. Data were collected by surveys administered in 38 European countries. Results indicate non-uniform implementation of event registration and classification, as well as incomplete or zero implementation of risk assessment and events analysis. Based on the survey results and analysis thereof, project leaders are currently drafting proposed guidelines entitled “Guidelines for patient safety in external beam radiotherapy – Guidelines on risk assessment and analysis of adverse-error events and near misses”. The present article describes the aims and current status of the project, including results of the surveys

  17. Quantitative dosimetric assessment for effect of gold nanoparticles as contrast media on radiotherapy planning

    Science.gov (United States)

    Tu, Shu-Ju; Yang, Pei-Ying; Hong, Ji-Hong; Lo, Ching-Jung

    2013-07-01

    In CT planning for radiation therapy, patients may be asked to have a medical procedure of contrast agent (CA) administration as required by their physicians. CA media improve quality of CT images and assist radiation oncologists in delineation of the target or organs with accuracy. However, dosimetric discrepancy may occur between scenarios in which CA media are present in CT planning and absent in treatment delivery. In recent preclinical experiments of small animals, gold nanoparticles (AuNPs) have been identified as an excellent contrast material of x-ray imaging. In this work, we quantitatively evaluate the effect of AuNPs to be used as a potential material of contrast enhancement in radiotherapy planning with an analytical phantom and clinical case. Conray 60, an iodine-based product for contrast enhancement in clinical uses, is included as a comparison. Other additional variables such as different concentrations of CA media, radiation delivery techniques and dose calculation algorithms are included. We consider 1-field AP, 4-field box, 7-field intensity modulated radiation therapy (IMRT) and a recent technique of volumetric modulated arc therapy (VMAT). CA media of AuNPs (Conray 60) with concentrations of 10%, 20%, 30%, 40% and 50% containing 28.2, 56.4, 84.6, 112.8 and 141.0 mg of gold (iodine) per mL were prepared prior to CT scanning. A virtual phantom with a target where nanoparticle media are loaded and clinical case of gastric lymphoma in which the Conray 60 media were given to the patient prior to the CT planning are included for the study. Compared to Conray 60 media with concentration of 10%/50%, Hounsfield units for AuNP media of 10%/50% are 322/1608 higher due to the fact that atomic number of Au (Z=79) is larger than I (Z=53). In consequence, dosimetric discrepancy of AuNPs is magnified between presence and absence of contrast media. It was found in the phantom study that percent dose differences between presence and absence of CA media may be

  18. Four Dimensional Graphene

    CERN Document Server

    Drissi, L B; Bousmina, M

    2011-01-01

    Mimicking pristine 2D graphene, we revisit the BBTW model for 4D lattice QCD given in ref.[5] by using the hidden SU(5) symmetry of the 4D hyperdiamond lattice H_4. We first study the link between the H_4 and SU(5); then we refine the BBTW 4D lattice action by using the weight vectors \\lambda_1, \\lambda_2, \\lambda_3, \\lambda_4, \\lambda_5 of the 5-dimensional representation of SU(5) satisfying {\\Sigma}_i\\lambda_i=0. After that we study explicitly the solutions of the zeros of the Dirac operator D in terms of the SU(5) simple roots \\alpha_1, \\alpha_2, \\alpha_3, \\alpha_4 generating H_4; and its fundamental weights \\omega_1, \\omega_2, \\omega_3, \\omega_4 which generate the reciprocal lattice H_4^\\ast. It is shown, amongst others, that these zeros live at the sites of H_4^\\ast; and the continuous limit D is given by ((id\\surd5)/2) \\gamma^\\muk_\\mu with d, \\gamma^\\mu and k_\\mu standing respectively for the lattice parameter of H_4, the usual 4 Dirac matrices and the 4D wave vector. Other features such as differences ...

  19. Differentiation of Brain Tumor Recurrence from Post-Radiotherapy Necrosis with 11C-Methionine PET: Visual Assessment versus Quantitative Assessment.

    Directory of Open Access Journals (Sweden)

    Ryogo Minamimoto

    Full Text Available The aim of this multi-center study was to assess the diagnostic capability of visual assessment in L-methyl-11C-methionine positron emission tomography (MET-PET for differentiating a recurrent brain tumor from radiation-induced necrosis after radiotherapy, and to compare it to the accuracy of quantitative analysis.A total of 73 brain lesions (glioma: 31, brain metastasis: 42 in 70 patients who underwent MET-PET were included in this study. Visual analysis was performed by comparison of MET uptake in the brain lesion with MET uptake in one of four regions (around the lesion, contralateral frontal lobe, contralateral area, and contralateral cerebellar cortex. The concordance rate and logistic regression analysis were used to evaluate the diagnostic ability of visual assessment. Receiver-operating characteristic curve analysis was used to compare visual assessment with quantitative assessment based on the lesion-to-normal (L/N ratio of MET uptake.Interobserver and intraobserver κ-values were highest at 0.657 and 0.714, respectively, when assessing MET uptake in the lesion compared to that in the contralateral cerebellar cortex. Logistic regression analysis showed that assessing MET uptake in the contralateral cerebellar cortex with brain metastasis was significantly related to the final result. The highest area under the receiver-operating characteristic curve (AUC with visual assessment for brain metastasis was 0.85, showing no statistically significant difference with L/Nmax of the contralateral brain (AUC = 0.89 or with L/Nmean of the contralateral cerebellar cortex (AUC = 0.89, which were the areas that were the highest in the quantitative assessment. For evaluation of gliomas, no specific candidate was confirmed among the four areas used in visual assessment, and no significant difference was seen between visual assessment and quantitative assessment.The visual assessment showed no significant difference from quantitative assessment of MET

  20. Results of postoperative {sup 90}Sr radiotherapy of keloids in view of patients' subjective assessment

    Energy Technology Data Exchange (ETDEWEB)

    Fraunholz, I.B.; Gerstenhauer, A.; Boettcher, H.D. [Frankfurt am Main Univ. (Germany). Dept. of Radiation Oncology

    2005-11-01

    Background and Purpose: As treatment of keloids is mainly a cosmetic indication, the authors investigated, beyond the recurrence rate, the patients' satisfaction with the result and its correlation with objective medical findings. Patients and Methods: 83 keloids of 66 patients had been irradiated after excision by a uniform protocol with 4 x 5 Gy (strontium-90 [{sup 90}Sr] surface applicator). A questionnaire was developed and sent out in which, above all, the satisfaction with the therapeutic and cosmetic outcome was obtained. These results were correlated with objective parameters and medical findings which were ascertained during an extra follow-up examination. Results: Among 18 of the 41 patients (44%), who had answered the questionnaire, 19 of the 53 keloids treated (36%) had relapsed. 61% of the patients were extremely or mainly satisfied with the therapeutic outcome, 51% extremely or mainly satisfied with the cosmetic outcome. The relief from former keloid-caused symptoms (therapeutic outcome: p=0.0005; cosmetic outcome: p=0.0011), the ear as keloid localization (p=0.0008 and p=0.0197), and male gender (therapeutic outcome: p=0.0423) were significantly associated with higher satisfaction. The recurrence rate as well as the extent of radiation side effects had no significant influence on patients' assessment. Conclusion: Cosmetic aspects like the dermal side effects and the patients' satisfaction should be taken into account when evaluating the results of radiotherapy in keloids. (orig.)

  1. Magnetic resonance imaging for assessment of parametrial tumour spread and regression patterns in adaptive cervix cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Maximilian P.; Fidarova, Elena [Dept. of Radiotherapy, Comprehensive Cancer Center, Medical Univ. of Vienna, Vienna (Austria)], e-mail: maximilian.schmid@akhwien.at; Poetter, Richard [Dept. of Radiotherapy, Comprehensive Cancer Center, Medical Univ. of Vienna, Vienna (Austria); Christian Doppler Lab. for Medical Radiation Research for Radiation Oncology, Medical Univ. of Vienna (Austria)] [and others

    2013-10-15

    Purpose: To investigate the impact of magnetic resonance imaging (MRI)-morphologic differences in parametrial infiltration on tumour response during primary radio chemotherapy in cervical cancer. Material and methods: Eighty-five consecutive cervical cancer patients with FIGO stages IIB (n = 59) and IIIB (n = 26), treated by external beam radiotherapy ({+-}chemotherapy) and image-guided adaptive brachytherapy, underwent T2-weighted MRI at the time of diagnosis and at the time of brachytherapy. MRI patterns of parametrial tumour infiltration at the time of diagnosis were assessed with regard to predominant morphology and maximum extent of parametrial tumour infiltration and were stratified into five tumour groups (TG): 1) expansive with spiculae; 2) expansive with spiculae and infiltrating parts; 3) infiltrative into the inner third of the parametrial space (PM); 4) infiltrative into the middle third of the PM; and 5) infiltrative into the outer third of the PM. MRI at the time of brachytherapy was used for identifying presence (residual vs. no residual disease) and signal intensity (high vs. intermediate) of residual disease within the PM. Left and right PM of each patient were evaluated separately at both time points. The impact of the TG on tumour remission status within the PM was analysed using {chi}2-test and logistic regression analysis. Results: In total, 170 PM were analysed. The TG 1, 2, 3, 4, 5 were present in 12%, 11%, 35%, 25% and 12% of the cases, respectively. Five percent of the PM were tumour-free. Residual tumour in the PM was identified in 19%, 68%, 88%, 90% and 85% of the PM for the TG 1, 2, 3, 4, and 5, respectively. The TG 3 - 5 had significantly higher rates of residual tumour in the PM in comparison to TG 1 + 2 (88% vs. 43%, p < 0.01). Conclusion: MRI-morphologic features of PM infiltration appear to allow for prediction of tumour response during external beam radiotherapy and chemotherapy. A predominantly infiltrative tumour spread at the

  2. Assessment of response of brain metastases to radiotherapy by PET imaging of apoptosis with 18F-ML-10

    International Nuclear Information System (INIS)

    Early assessment of tumor response to therapy is vital for treatment optimization for the individual cancer patient. Induction of apoptosis is an early and nearly universal effect of anticancer therapies. The purpose of this study was to assess the performance of 18F-ML-10, a novel PET radiotracer for apoptosis, as a tool for the early detection of response of brain metastases to whole-brain radiation therapy (WBRT). Ten patients with brain metastases treated with WBRT at 30 Gy in ten daily fractions were enrolled in this trial. Each patient underwent two 18F-ML-10 PET scans, one prior to the radiation therapy (baseline scan), and the second after nine or ten fractions of radiotherapy (follow-up scan). MRI was performed at 6-8 weeks following completion of the radiation therapy. Early treatment-induced changes in tumor 18F-ML-10 uptake on the PET scan were measured by voxel-based analysis, and were then evaluated by correlation analysis as predictors of the extent of later changes in tumor anatomical dimensions as seen on MRI scans 6-8 weeks after completion of therapy. In all ten patients, all brain lesions were detected by both MRI and the 18F-ML-10 PET scan. A highly significant correlation was found between early changes on the 18F-ML-10 scan and later changes in tumor anatomical dimensions (r = 0.9). These results support the potential of 18F-ML-10 PET as a novel tool for the early detection of response of brain metastases to WBRT. (orig.)

  3. Radiomics versus physician assessment for the early prediction of local cancer recurrence after stereotactic radiotherapy for lung cancer

    Science.gov (United States)

    Mattonen, Sarah A.; Johnson, Carol; Palma, David A.; Rodrigues, George; Louie, Alexander V.; Senan, Suresh; Yeung, Timothy P. C.; Ward, Aaron D.

    2016-03-01

    Stereotactic ablative radiotherapy (SABR) has recently become a standard treatment option for patients with early-stage lung cancer, which achieves local control rates similar to surgery. Local recurrence following SABR typically presents after one year post-treatment. However, benign radiological changes mimicking local recurrence can appear on CT imaging following SABR, complicating the assessment of response. We hypothesize that subtle changes on early post- SABR CT images are important in predicting the eventual incidence of local recurrence and would be extremely valuable to support timely salvage interventions. The objective of this study was to extract radiomic image features on post-SABR follow-up images for 45 patients (15 with local recurrence and 30 without) to aid in the early prediction of local recurrence. Three blinded thoracic radiation oncologists were also asked to score follow-up images as benign injury or local recurrence. A radiomic signature consisting of five image features demonstrated a classification error of 24%, false positive rate (FPR) of 24%, false negative rate (FNR) of 23%, and area under the receiver operating characteristic curve (AUC) of 0.85 at 2-5 months post-SABR. At the same time point, three physicians assessed the majority of images as benign injury for overall errors of 34-37%, FPRs of 0-4%, and FNRs of 100%. These results suggest that radiomics can detect early changes associated with local recurrence which are not typically considered by physicians. We aim to develop a decision support system which could potentially allow for early salvage therapy of patients with local recurrence following SABR.

  4. Stereotactic radiotherapy for vestibular schwannoma

    DEFF Research Database (Denmark)

    Muzevic, Dario; Legcevic, Jelena; Splavski, Bruno;

    2014-01-01

    BACKGROUND: Vestibular schwannomas (acoustic neuromas) are common benign tumours that arise from the Schwann cells of the vestibular nerve. Management options include observation with neuroradiological follow-up, microsurgical resection and stereotactic radiotherapy. OBJECTIVES: To assess...

  5. Neurocognitive function impairment after whole brain radiotherapy for brain metastases: actual assessment

    International Nuclear Information System (INIS)

    Whole brain radiation therapy (WBRT) is an effective treatment in brain metastases and, when combined with local treatments such as surgery and stereotactic radiosurgery, gives the best brain control. Nonetheless, WBRT is often omitted after local treatment due to its potential late neurocognitive effects. Publications on radiation-induced neurotoxicity have used different assessment methods, time to assessment, and definition of impairment, thus making it difficult to accurately assess the rate and magnitude of the neurocognitive decline that can be expected. In this context, and to help therapeutic decision making, we have conducted this literature review, with the aim of providing an average incidence, magnitude and time to occurrence of radio-induced neurocognitive decline. We reviewed all English language published articles on neurocognitive effects of WBRT for newly diagnosed brain metastases or with a preventive goal in adult patients, with any methodology (MMSE, battery of neurcognitive tests) with which baseline status was provided. We concluded that neurocognitive decline is predominant at 4 months, strongly dependant on brain metastases control, partially solved at later time, graded 1 on a SOMA-LENT scale (only 8% of grade 2 and more), insufficiently assessed in long-term survivors, thus justifying all efforts to reduce it through irradiation modulation

  6. Investigation of four-dimensional computed tomography-based pulmonary ventilation imaging in patients with emphysematous lung regions

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Tokihiro; Loo, Billy W Jr; Keall, Paul J [Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Dr, Stanford, CA 94305-5847 (United States); Kabus, Sven; Lorenz, Cristian; Von Berg, Jens; Blaffert, Thomas [Department of Digital Imaging, Philips Research Europe, Roentgenstrasse 24-26, D-22335 Hamburg (Germany); Klinder, Tobias, E-mail: Tokihiro@stanford.edu [Clinical Informatics, Interventional, and Translational Solutions, Philips Research North America, Briarcliff Manor, NY 10510 (United States)

    2011-04-07

    A pulmonary ventilation imaging technique based on four-dimensional (4D) computed tomography (CT) has advantages over existing techniques. However, physiologically accurate 4D-CT ventilation imaging has not been achieved in patients. The purpose of this study was to evaluate 4D-CT ventilation imaging by correlating ventilation with emphysema. Emphysematous lung regions are less ventilated and can be used as surrogates for low ventilation. We tested the hypothesis: 4D-CT ventilation in emphysematous lung regions is significantly lower than in non-emphysematous regions. Four-dimensional CT ventilation images were created for 12 patients with emphysematous lung regions as observed on CT, using a total of four combinations of two deformable image registration (DIR) algorithms: surface-based (DIR{sup sur}) and volumetric (DIR{sup vol}), and two metrics: Hounsfield unit (HU) change (V{sub HU}) and Jacobian determinant of deformation (V{sub Jac}), yielding four ventilation image sets per patient. Emphysematous lung regions were detected by density masking. We tested our hypothesis using the one-tailed t-test. Visually, different DIR algorithms and metrics yielded spatially variant 4D-CT ventilation images. The mean ventilation values in emphysematous lung regions were consistently lower than in non-emphysematous regions for all the combinations of DIR algorithms and metrics. V{sub HU} resulted in statistically significant differences for both DIR{sup sur} (0.14 {+-} 0.14 versus 0.29 {+-} 0.16, p = 0.01) and DIR{sup vol} (0.13 {+-} 0.13 versus 0.27 {+-} 0.15, p < 0.01). However, V{sub Jac} resulted in non-significant differences for both DIR{sup sur} (0.15 {+-} 0.07 versus 0.17 {+-} 0.08, p = 0.20) and DIR{sup vol} (0.17 {+-} 0.08 versus 0.19 {+-} 0.09, p = 0.30). This study demonstrated the strong correlation between the HU-based 4D-CT ventilation and emphysema, which indicates the potential for HU-based 4D-CT ventilation imaging to achieve high physiologic accuracy. A

  7. Investigation of four-dimensional computed tomography-based pulmonary ventilation imaging in patients with emphysematous lung regions

    International Nuclear Information System (INIS)

    A pulmonary ventilation imaging technique based on four-dimensional (4D) computed tomography (CT) has advantages over existing techniques. However, physiologically accurate 4D-CT ventilation imaging has not been achieved in patients. The purpose of this study was to evaluate 4D-CT ventilation imaging by correlating ventilation with emphysema. Emphysematous lung regions are less ventilated and can be used as surrogates for low ventilation. We tested the hypothesis: 4D-CT ventilation in emphysematous lung regions is significantly lower than in non-emphysematous regions. Four-dimensional CT ventilation images were created for 12 patients with emphysematous lung regions as observed on CT, using a total of four combinations of two deformable image registration (DIR) algorithms: surface-based (DIRsur) and volumetric (DIRvol), and two metrics: Hounsfield unit (HU) change (VHU) and Jacobian determinant of deformation (VJac), yielding four ventilation image sets per patient. Emphysematous lung regions were detected by density masking. We tested our hypothesis using the one-tailed t-test. Visually, different DIR algorithms and metrics yielded spatially variant 4D-CT ventilation images. The mean ventilation values in emphysematous lung regions were consistently lower than in non-emphysematous regions for all the combinations of DIR algorithms and metrics. VHU resulted in statistically significant differences for both DIRsur (0.14 ± 0.14 versus 0.29 ± 0.16, p = 0.01) and DIRvol (0.13 ± 0.13 versus 0.27 ± 0.15, p Jac resulted in non-significant differences for both DIRsur (0.15 ± 0.07 versus 0.17 ± 0.08, p = 0.20) and DIRvol (0.17 ± 0.08 versus 0.19 ± 0.09, p = 0.30). This study demonstrated the strong correlation between the HU-based 4D-CT ventilation and emphysema, which indicates the potential for HU-based 4D-CT ventilation imaging to achieve high physiologic accuracy. A further study is needed to confirm these results.

  8. Advice concerning radiotherapy

    International Nuclear Information System (INIS)

    Dutch National cancer incidence figures were calculated by using the reliable data on cancer incidence in the Eindhoven area and population forecasts and information obtained from the Central Bureau of Statistics. Several radiotherapy departments suffer from under capacity (a lack of resources and understaffing). Data have also shown that 35% of cancer patients receive radiotherapy, instead of 50%. Calculations have been made by the committee on the present and future needs with regard to equipment and staff. In 1983, the number of megavoltage therapy units amounted to 38, but should have been 65. It should be 80 in 1990 and 90 in 2000. Since building and installing such equipment is a lengthy process a considerable effort is needed to make up for the arrears. The committee advocates the extension of the system of regional cooperation in cancer care (comprehensive cancer centres), in which radiotherapy departments play a crucial role. Working parties from the committee provided a comprehensive description of current radiotherapy practice with reference to physical, technical, clinical and management aspects. Another working party assessed the results of cancer treatment with regard to many different tumour sites. Recent and expected developments were analysed or indicated. The Radiotherapy Committee commissioned an external team to conduct a project to achieve a picture of future developments using methods different to those of the committee's. An interim advice has been added on this subject. (Auth.)

  9. Objective assessment of cosmetic outcome after targeted intraoperative radiotherapy in breast cancer

    DEFF Research Database (Denmark)

    Keshtgar, Mohammed R S; Williams, Norman R; Bulsara, Max;

    2013-01-01

    thereafter for up to 5 years. The photographs were analysed by BCCT.core, a validated software which produces a composite score based on symmetry, colour and scar. 342 patients were assessed, median age at baseline 64 years (IQR 59-68). The scores were dichotomised into Excellent and Good (EG), and Fair...... and Poor (FP). There were statistically significant increases in the odds of having an outcome of EG for patients in the TARGIT group relative to the EBRT group at year 1 (OR 2.07, 95 % CI 1.12-3.85, p = 0.021) and year 2 (OR 2.11, 95 % CI 1.0-4.45, p = 0.05). Following a totally objective assessment...

  10. Four-dimensional Cone Beam CT Reconstruction and Enhancement using a Temporal Non-Local Means Method

    CERN Document Server

    Jia, Xun; Lou, Yifei; Sonke, Jan-Jakob; Jiang, Steve B

    2012-01-01

    Four-dimensional Cone Beam Computed Tomography (4D-CBCT) has been developed to provide respiratory phase resolved volumetric imaging in image guided radiation therapy (IGRT). Inadequate number of projections in each phase bin results in low quality 4D-CBCT images with obvious streaking artifacts. In this work, we propose two novel 4D-CBCT algorithms: an iterative reconstruction algorithm and an enhancement algorithm, utilizing a temporal nonlocal means (TNLM) method. We define a TNLM energy term for a given set of 4D-CBCT images. Minimization of this term favors those 4D-CBCT images such that any anatomical features at one spatial point at one phase can be found in a nearby spatial point at neighboring phases. 4D-CBCT reconstruction is achieved by minimizing a total energy containing a data fidelity term and the TNLM energy term. As for the image enhancement, 4D-CBCT images generated by the FDK algorithm are enhanced by minimizing the TNLM function while keeping the enhanced images close to the FDK results. A...

  11. Four-dimensional variational data assimilation for inverse modelling of atmospheric methane emissions: method and comparison with synthesis inversion

    Directory of Open Access Journals (Sweden)

    J. F. Meirink

    2008-11-01

    Full Text Available A four-dimensional variational (4D-Var data assimilation system for inverse modelling of atmospheric methane emissions is presented. The system is based on the TM5 atmospheric transport model. It can be used for assimilating large volumes of measurements, in particular satellite observations and quasi-continuous in-situ observations, and at the same time it enables the optimization of a large number of model parameters, specifically grid-scale emission rates. Furthermore, the variational method allows to estimate uncertainties in posterior emissions. Here, the system is applied to optimize monthly methane emissions over a 1-year time window on the basis of surface observations from the NOAA-ESRL network. The results are rigorously compared with an analogous inversion by Bergamaschi et al. (2007, which was based on the traditional synthesis approach. The posterior emissions as well as their uncertainties obtained in both inversions show a high degree of consistency. At the same time we illustrate the advantage of 4D-Var in reducing aggregation errors by optimizing emissions at the grid scale of the transport model. The full potential of the assimilation system is exploited in Meirink et al. (2008, who use satellite observations of column-averaged methane mixing ratios to optimize emissions at high spatial resolution, taking advantage of the zooming capability of the TM5 model.

  12. Restoration of four-dimensional diffeomorphism covariance in canonical general relativity: An intrinsic Hamilton-Jacobi approach

    Science.gov (United States)

    Salisbury, Donald; Renn, Jürgen; Sundermeyer, Kurt

    2016-02-01

    Classical background independence is reflected in Lagrangian general relativity through covariance under the full diffeomorphism group. We show how this independence can be maintained in a Hamilton-Jacobi approach that does not accord special privilege to any geometric structure. Intrinsic space-time curvature-based coordinates grant equal status to all geometric backgrounds. They play an essential role as a starting point for inequivalent semiclassical quantizations. The scheme calls into question Wheeler’s geometrodynamical approach and the associated Wheeler-DeWitt equation in which 3-metrics are featured geometrical objects. The formalism deals with variables that are manifestly invariant under the full diffeomorphism group. Yet, perhaps paradoxically, the liberty in selecting intrinsic coordinates is precisely as broad as is the original diffeomorphism freedom. We show how various ideas from the past five decades concerning the true degrees of freedom of general relativity can be interpreted in light of this new constrained Hamiltonian description. In particular, we show how the Kuchař multi-fingered time approach can be understood as a means of introducing full four-dimensional diffeomorphism invariants. Every choice of new phase space variables yields new Einstein-Hamilton-Jacobi constraining relations, and corresponding intrinsic Schrödinger equations. We show how to implement this freedom by canonical transformation of the intrinsic Hamiltonian. We also reinterpret and rectify significant work by Dittrich on the construction of “Dirac observables.”

  13. The finite-size scaling study of four-dimensional Ising model in the presence of external magnetic field

    International Nuclear Information System (INIS)

    The four-dimensional ferromagnetic Ising model in external magnetic field is simulated on the Creutz cellular automaton algorithm using finite-size lattices with linear dimension 4 <= L <= 8. The critical temperature value of infinite lattice, Tcchi (∞) approx 6.680(1) obtained for h = 0 agrees well with the values Tc (infinity) approx 6.68 obtained previously using different methods. Moreover, h = 0.00025 in our work also agrees with all the results obtained from h = 0 in the literature. However, there are no works for h not= 0 in the literature. The value of the field critical exponent (δ = 3.0136(3)) is in good agreement with δ = 3 which is obtained from scaling law of Widom. In spite of the finite-size scaling relations of IML(t)| and χL(t) for 0 <= h <= 0.001 are verified; however, in the cases of 0.0025 <= h <= 0.1 they are not verified

  14. Four-dimensional cardiac reconstruction from rotational x-ray sequences: first results for 4D coronary angiography

    Science.gov (United States)

    Hansis, Eberhard; Schomberg, Hermann; Erhard, Klaus; Dössel, Olaf; Grass, Michael

    2009-02-01

    The tomographic reconstruction of the beating heart requires dedicated methods. One possibility is gated reconstruction, where only data corresponding to a certain motion state are incorporated. Another one is motioncompensated reconstruction with a pre-computed motion vector field, which requires a preceding estimation of the motion. Here, results of a new approach are presented: simultaneous reconstruction of a three-dimensional object and its motion over time, yielding a fully four-dimensional representation. The object motion is modeled by a time-dependent elastic transformation. The reconstruction is carried out with an iterative gradient-descent algorithm which simultaneously optimizes the three-dimensional image and the motion parameters. The method was tested on a simulated rotational X-ray acquisition of a dynamic coronary artery phantom, acquired on a C-arm system with a slowly rotating C-arm. Accurate reconstruction of both absorption coefficient and motion could be achieved. First results from experiments on clinical rotational X-ray coronary angiography data are shown. The resulting reconstructions enable the analysis of both static properties, such as vessel geometry and cross-sectional areas, and dynamic properties, like magnitude, speed, and synchrony of motion during the cardiac cycle.

  15. A novel color image encryption algorithm based on genetic recombination and the four-dimensional memristive hyperchaotic system

    Science.gov (United States)

    Chai, Xiu-Li; Gan, Zhi-Hua; Lu, Yang; Zhang, Miao-Hui; Chen, Yi-Ran

    2016-10-01

    Recently, many image encryption algorithms based on chaos have been proposed. Most of the previous algorithms encrypt components R, G, and B of color images independently and neglect the high correlation between them. In the paper, a novel color image encryption algorithm is introduced. The 24 bit planes of components R, G, and B of the color plain image are obtained and recombined into 4 compound bit planes, and this can make the three components affect each other. A four-dimensional (4D) memristive hyperchaotic system generates the pseudorandom key streams and its initial values come from the SHA 256 hash value of the color plain image. The compound bit planes and key streams are confused according to the principles of genetic recombination, then confusion and diffusion as a union are applied to the bit planes, and the color cipher image is obtained. Experimental results and security analyses demonstrate that the proposed algorithm is secure and effective so that it may be adopted for secure communication. Project supported by the National Natural Science Foundation of China (Grant Nos. 61203094 and 61305042), the Natural Science Foundation of the United States (Grant Nos. CNS-1253424 and ECCS-1202225), the Science and Technology Foundation of Henan Province, China (Grant No. 152102210048), the Foundation and Frontier Project of Henan Province, China (Grant No. 162300410196), the Natural Science Foundation of Educational Committee of Henan Province, China (Grant No. 14A413015), and the Research Foundation of Henan University, China (Grant No. xxjc20140006).

  16. An Alternative View of the Universe Structure (on the invalidity of the four dimensional space-time concept)

    CERN Document Server

    Hovsepian, Felix

    2007-01-01

    The model of the Universe in this paper uses equations of the unperturbed Keplerian motion. They have been updated, complementied and generalized when the solution of these equations is the characteristic function of a random value from the theory of probabilities. Argument of the differential equation in this case is any more time, an interval of time between sections of a random stationary prosess. In this paper this time interval is referred to as flexible (elastic) time due to its many non-trivial properties. It is proved flexible time does not depend on the space which makes invalid the four dimensional space-time concept. The Universe becomes stationary and Eucledian. It is proved: 1. the advavce of Mercury's perihelion versus the predictions in accordance with the universal gravity law results inequality of the coefficients in the correlation equations of Keplerian moution along axes x, y and z; 2. the velocity of propagation of harmonic oscillation in the Uneverse is not constant; 3. long-range intera...

  17. The finite-size scaling study of four-dimensional Ising model in the presence of external magnetic field

    Science.gov (United States)

    Merdan, Ziya; Kürkçü, Cihan; Öztürk, Mustafa K.

    2014-12-01

    The four-dimensional ferromagnetic Ising model in external magnetic field is simulated on the Creutz cellular automaton algorithm using finite-size lattices with linear dimension 4 ≤ L ≤ 8. The critical temperature value of infinite lattice, Tc χ ( ∞ ) = 6 , 680 (1) obtained for h = 0 agrees well with the values T c ( ∞ ) ≈ 6.68 obtained previously using different methods. Moreover, h = 0.00025 in our work also agrees with all the results obtained from h = 0 in the literature. However, there are no works for h ≠ 0 in the literature. The value of the field critical exponent (δ = 3.0136(3)) is in good agreement with δ = 3 which is obtained from scaling law of Widom. In spite of the finite-size scaling relations of | M L ( t ) | and χ L ( t ) for 0 ≤ h ≤ 0.001 are verified; however, in the cases of 0.0025 ≤ h ≤ 0.1 they are not verified.

  18. The "universal property" of Horizon Entropy Sum of Black Holes in Four Dimensional Asymptotical (anti-)de-Sitter Spacetime Background

    CERN Document Server

    Wang, Jia; Meng, Xin-he

    2014-01-01

    We present a new universal property of entropy, that is the entropy sum relation of black holes in four dimensional (anti-)de-Sitter asymptotical back- ground. They depend only on the cosmological constant with the necessary e?ect of the un-physical virtual horizon included in the spacetime where only the cosmological constant, mass of black hole, rotation parameter and Maxwell ?eld exist. When there is more extra matter ?eld in the spacetime, one will ?nd the entropy sum is also dependent of the strength of these extra matter ?eld. For both cases, we conclude that the entropy sum does not depend on the con- versed charges M, Q and J, while it does depend on the property of background spacetime. We will mainly test the entropy sum relation in static, stationary black hole and some black hole with extra matter source (scalar hair and higher curvature) in the asymptotical (anti-)de-sitter spacetime background. Besides, we point out a newly found counter example of the mass independence of the "entropy product" ...

  19. The Prognostic Value of a Four-Dimensional CT Angiography-Based Collateral Grading Scale for Reperfusion Therapy in Acute Ischemic Stroke Patients

    Science.gov (United States)

    Zhang, Sheng; Chen, Weili; Tang, Huan; Han, Quan; Yan, Shenqiang; Zhang, Xiaocheng; Chen, Qingmeng; Parsons, Mark; Wang, Shaoshi; Lou, Min

    2016-01-01

    Objective Leptomeningeal collaterals, which affects tissue fate, are still challenging to assess. Four-dimensional CT angiography (4D CTA) originated from CT perfusion (CTP) provides the possibility of non-invasive and time-resolved assessment of leptomeningeal collateral flow. We sought to develop a comprehensive rating system to integrate the speed and extent of collateral flow on 4D CTA, and investigate its prognostic value for reperfusion therapy in acute ischemic stroke (AIS) patients. Methods We retrospectively studied 80 patients with M1 ± internal carotid artery (ICA) occlusion who had baseline CTP before intravenous thrombolysis. The velocity and extent of collaterals were evaluated by regional leptomeningeal collateral score on peak phase (rLMC-P) and temporally fused intensity projections (tMIP) (rLMC-M) on 4D CTA, respectively. The cutoffs of rLMC-P and rLMC-M score for predicting good outcome (mRS score ≤ 2) were integrated to develop the collateral grading scale (CGS) (rating from 0–2). Results The CGS score was correlated with 3-months mRS score (non-recanalizers: ρ = -0.495, p = 0.01; recanalizers: ρ = -0.671, p < 0.001). Patients with intermediate or good collaterals (CGS score of 1 and 2) who recanalized were more likely to have good outcome than those without recanalization (p = 0.038, p = 0.018), while there was no significant difference in outcome in patients with poor collaterals (CGS score of 0) stratified by recanalization (p = 0.227). Conclusions Identification of collaterals based on CGS may help to select good responders to reperfusion therapy in patients with large artery occlusion. PMID:27505435

  20. 3D quantitative assessment of response to fractionated stereotactic radiotherapy and single-session stereotactic radiosurgery of vestibular schwannoma

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, T. [The Johns Hopkins Hospital School of Medicine, Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Neuroradiology, Baltimore, MD (United States); University Medical Center Hamburg-Eppendorf, Department of Diagnostic and Interventional Neuroradiology, Hamburg (Germany); Chapiro, J. [The Johns Hopkins Hospital School of Medicine, Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Interventional Radiology, Baltimore, MD (United States); Lin, M. [Philips Research North America, Ultrasound Imaging and Interventions (UII), Briarcliff Manor, NY (United States); Geschwind, J.F. [The Johns Hopkins Hospital School of Medicine, Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Interventional Radiology, Baltimore, MD (United States); Yale University School of Medicine, Department of Radiology and Imaging Science, New Haven, CT (United States); Kleinberg, L. [The Johns Hopkins University School of Medicine, Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD (United States); Rigamonti, D.; Jusue-Torres, I.; Marciscano, A.E. [The Johns Hopkins University School of Medicine, Department of Neurological Surgery, Baltimore, MD (United States); Yousem, D.M. [The Johns Hopkins Hospital School of Medicine, Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Neuroradiology, Baltimore, MD (United States)

    2016-03-15

    To determine clinical outcome of patients with vestibular schwannoma (VS) after treatment with fractionated stereotactic radiotherapy (FSRT) and single-session stereotactic radiosurgery (SRS) by using 3D quantitative response assessment on MRI. This retrospective analysis included 162 patients who underwent radiation therapy for sporadic VS. Measurements on T1-weighted contrast-enhanced MRI (in 2-year post-therapy intervals: 0-2, 2-4, 4-6, 6-8, 8-10, 10-12 years) were taken for total tumour volume (TTV) and enhancing tumour volume (ETV) based on a semi-automated technique. Patients were considered non-responders (NRs) if they required subsequent microsurgical resection or developed radiological progression and tumour-related symptoms. Median follow-up was 4.1 years (range: 0.4-12.0). TTV and ETV decreased for both the FSRT and SRS groups. However, only the FSRT group achieved significant tumour shrinkage (p < 0.015 for TTV, p < 0.005 for ETV over time). The 11 NRs showed proportionally greater TTV (median TTV pre-treatment: 0.61 cm{sup 3}, 8-10 years after: 1.77 cm{sup 3}) and ETV despite radiation therapy compared to responders (median TTV pre-treatment: 1.06 cm{sup 3}; 10-12 years after: 0.81 cm{sup 3}; p = 0.001). 3D quantification of VS showed a significant decrease in TTV and ETV on FSRT-treated patients only. NR had significantly greater TTV and ETV over time. (orig.)

  1. Measurement of the transverse four-dimensional beam rms-emittance of an intense uranium beam at 11.4 MeV/u

    Science.gov (United States)

    Xiao, C.; Groening, L.; Gerhard, P.; Maier, M.; Mickat, S.; Vormann, H.

    2016-06-01

    Knowledge of the transverse four-dimensional beam rms-parameters is essential for applications that involve lattice elements that couple the two transverse degrees of freedom (planes). Usually pepper-pots are used for measuring these beam parameters. However, for ions their application is limited to energies below 150 keV/u. This contribution is on measurements of the full transverse four-dimensional second-moments beam matrix of high intensity uranium ions at an energy of 11.4 MeV/u. The combination of skew quadrupoles with a slit/grid emittance measurement device has been successfully applied.

  2. Personalized Assessment of kV Cone Beam Computed Tomography Doses in Image-guided Radiotherapy of Pediatric Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yibao [Beijing Key Lab of Medical Physics and Engineering, Peking University, Beijing (China); Yan Yulong [Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Nath, Ravinder [Department of Therapeutic Radiology, Yale University, New Haven, Connecticut (United States); Bao Shanglian [Beijing Key Lab of Medical Physics and Engineering, Peking University, Beijing (China); Deng Jun, E-mail: jun.deng@yale.edu [Department of Therapeutic Radiology, Yale University, New Haven, Connecticut (United States)

    2012-08-01

    Purpose: To develop a quantitative method for the estimation of kV cone beam computed tomography (kVCBCT) doses in pediatric patients undergoing image-guided radiotherapy. Methods and Materials: Forty-two children were retrospectively analyzed in subgroups of different scanned regions: one group in the head-and-neck and the other group in the pelvis. Critical structures in planning CT images were delineated on an Eclipse treatment planning system before being converted into CT phantoms for Monte Carlo simulations. A benchmarked EGS4 Monte Carlo code was used to calculate three-dimensional dose distributions of kVCBCT scans with full-fan high-quality head or half-fan pelvis protocols predefined by the manufacturer. Based on planning CT images and structures exported in DICOM RT format, occipital-frontal circumferences (OFC) were calculated for head-and-neck patients using DICOMan software. Similarly, hip circumferences (HIP) were acquired for the pelvic group. Correlations between mean organ doses and age, weight, OFC, and HIP values were analyzed with SigmaPlot software suite, where regression performances were analyzed with relative dose differences (RDD) and coefficients of determination (R{sup 2}). Results: kVCBCT-contributed mean doses to all critical structures decreased monotonically with studied parameters, with a steeper decrease in the pelvis than in the head. Empirical functions have been developed for a dose estimation of the major organs at risk in the head and pelvis, respectively. If evaluated with physical parameters other than age, a mean RDD of up to 7.9% was observed for all the structures in our population of 42 patients. Conclusions: kVCBCT doses are highly correlated with patient size. According to this study, weight can be used as a primary index for dose assessment in both head and pelvis scans, while OFC and HIP may serve as secondary indices for dose estimation in corresponding regions. With the proposed empirical functions, it is possible

  3. Assessment of quality of life in patients with rectal cancer treated by preoperative radiotherapy: A longitudinal prospective study

    International Nuclear Information System (INIS)

    Purpose: To assess prospectively the quality of life (QOL) of patients treated by preoperative radiotherapy (RT) and surgery for locally advanced rectal cancer. Methods and materials: We studied 53 patients treated with bi-fractionated RT (50 Gy in 40 fractions within 4 weeks) followed at a median interval of 45 days by abdominoperineal resection in 11 patients and low anterior resection in 42 patients. Their QOL was assessed using two self-rating questionnaires developed by the European Organization for Research and Treatment of Cancer (EORTC): one was cancer specific (EORTC QLQ-C30) and one was site specific (EORTC QLQ-C38). The questionnaires were completed before RT and 12-16 months after RT, at which time 17 patients had undergone colostomy. We hypothesized that at least some scores of the various scales would vary between the two analyses. Results: Compared with the pre-RT scores, at 1 year, patients reported statistically significant improvement in their emotional state (median 75 vs. 100, p <0.0001), perspective of the future (67 vs. 100, p = 0.0004), and their global QOL (75 vs. 83, p = 0.0008), as well as a decrease in GI symptoms (13 vs. 0, p = 0.002). However, the sexual dysfunction score increased significantly, particularly in men (17 vs. 83, p = 0.0045), and a trend toward a lower body image score was observed (100 vs. 89, p = 0.068). At 1 year, patients with colostomies reported similar or significantly improved symptom scores for fatigue, pain, GI problems, and sleep disturbance, but no such improvements were observed in patients without stomas. Conclusion: One year after combined treatment for locally advanced rectal cancer, patients exhibited statistically significant improvement in some important QOL outcomes, including global QOL, despite a decrease in sexual function and body image. Any additional improvement in QOL outcome may require refinements in the RT and surgical techniques to reduce late sequelae, particularly sexual dysfunction. Our

  4. Scapholunate kinematics of asymptomatic wrists in comparison with symptomatic contralateral wrists using four-dimensional CT examinations: initial clinical experience

    Energy Technology Data Exchange (ETDEWEB)

    Demehri, Shadpour; Hafezi-Nejad, Nima; Morelli, John N.; Thakur, Uma; Eng, John [Johns Hopkins University, Musculoskeletal Radiology, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Lifchez, Scott D.; Shores, Jaimie T. [Johns Hopkins University, Department of Plastic and Reconstructive Surgery, Baltimore, MD (United States); Means, Kenneth R. [MedStar Union Memorial Hospital, The Curtis National Hand Center, Baltimore, MD (United States)

    2016-04-15

    Using four-dimensional CT scan (4DCT), we aimed at showing the kinematics of scapholunate (SL) interval in asymptomatic wrists in comparison with symptomatic contralateral wrists with inconclusive radiographic findings. This is an IRB approved, HIPPA compliant, retrospective study. Patients suspected of SL interosseous ligament (SLIL) injuries were referred for further evaluation of chronic wrist pain (>3 months). Twelve wrists (11 subjects) with chronic symptoms and inconclusive plain radiographs and 10 asymptomatic wrists (in 10 different subjects) were scanned using 4DCT. The minimum SL interval was measured during three wrist motions: relaxed-to-clenched fist, flexion-to-extension, and radial-to-ulnar-deviation. Changes were recorded using double-oblique multiplanar reformation technique. We extracted the normal limits of the SL interval as measured by dynamic CT scanning during active motion in asymptomatic wrists. In asymptomatic wrists, the average SL interval was observed to be smaller than 1 mm during all motions. In symptomatic wrists, during exams performed with clenched fist (SL interval (mean ± SD) = 2.53 ± 1.19 mm), extension (2.54 ± 1.48 mm) or ulnar deviation (2.06 ± 1.12 mm), the average SL interval was more than 2 mm. In contrast to symptomatic wrists, no significant change in SL interval measurements was detected during wrist motions in asymptomatic wrists. There was a mild to moderate correlation between SL interval change and presence/absence of symptoms (point-biserial correlation coefficients: 0.29-0.55). In patients with wrist pain suspicious for SLIL injury and inconclusive radiographs, SL interval increase can be detected with 4DCT in the symptomatic wrist compared to the asymptomatic wrist. (orig.)

  5. Determination of patient-specific internal gross tumor volumes for lung cancer using four-dimensional computed tomography

    International Nuclear Information System (INIS)

    To determine the optimal approach to delineating patient-specific internal gross target volumes (IGTV) from four-dimensional (4-D) computed tomography (CT) image data sets used in the planning of radiation treatment for lung cancers. We analyzed 4D-CT image data sets of 27 consecutive patients with non-small-cell lung cancer (stage I: 17, stage III: 10). The IGTV, defined to be the envelope of respiratory motion of the gross tumor volume in each 4D-CT data set was delineated manually using four techniques: (1) combining the gross tumor volume (GTV) contours from ten respiratory phases (IGTVAllPhases); (2) combining the GTV contours from two extreme respiratory phases (0% and 50%) (IGTV2Phases); (3) defining the GTV contour using the maximum intensity projection (MIP) (IGTVMIP); and (4) defining the GTV contour using the MIP with modification based on visual verification of contours in individual respiratory phase (IGTVMIP-Modified). Using the IGTVAllPhases as the optimum IGTV, we compared volumes, matching indices, and extent of target missing using the IGTVs based on the other three approaches. The IGTVMIP and IGTV2Phases were significantly smaller than the IGTVAllPhases (p < 0.006 for stage I and p < 0.002 for stage III). However, the values of the IGTVMIP-Modified were close to those determined from IGTVAllPhases (p = 0.08). IGTVMIP-Modified also matched the best with IGTVAllPhases. IGTVMIP and IGTV2Phases underestimate IGTVs. IGTVMIP-Modified is recommended to improve IGTV delineation in lung cancer

  6. Correlation of primary middle and distal esophageal cancers motion with surrounding tissues using four-dimensional computed tomography

    Science.gov (United States)

    Wang, Wei; Li, Jianbin; Zhang, Yingjie; Shao, Qian; Xu, Min; Guo, Bing; Shang, Dongping

    2016-01-01

    Purpose To investigate the correlation of gross tumor volume (GTV) motion with the structure of interest (SOI) motion and volume variation for middle and distal esophageal cancers using four-dimensional computed tomography (4DCT). Patients and methods Thirty-three patients with middle or distal esophageal carcinoma underwent 4DCT simulation scan during free breathing. All image sets were registered with 0% phase, and the GTV, apex of diaphragm, lung, and heart were delineated on each phase of the 4DCT data. The position of GTV and SOI was identified in all 4DCT phases, and the volume of lung and heart was also achieved. The phase relationship between the GTV and SOI was estimated through Pearson’s correlation test. Results The mean peak-to-peak displacement of all primary tumors in the lateral (LR), anteroposterior (AP), and superoinferior (SI) directions was 0.13 cm, 0.20 cm, and 0.30 cm, respectively. The SI peak-to-peak motion of the GTV was defined as the greatest magnitude of motion. The displacement of GTV correlated well with heart in three dimensions and significantly associated with bilateral lung in LR and SI directions. A significant correlation was found between the GTV and apex of the diaphragm in SI direction (rleft=0.918 and rright=0.928). A significant inverse correlation was found between GTV motion and varying lung volume, but the correlation was not significant with heart (rLR=−0.530, rAP=−0.531, and rSI=−0.588) during respiratory cycle. Conclusion For middle and distal esophageal cancers, GTV should expand asymmetric internal margins. The primary tumor motion has quite good correlation with diaphragm, heart, and lung.

  7. Scapholunate kinematics of asymptomatic wrists in comparison with symptomatic contralateral wrists using four-dimensional CT examinations: initial clinical experience

    International Nuclear Information System (INIS)

    Using four-dimensional CT scan (4DCT), we aimed at showing the kinematics of scapholunate (SL) interval in asymptomatic wrists in comparison with symptomatic contralateral wrists with inconclusive radiographic findings. This is an IRB approved, HIPPA compliant, retrospective study. Patients suspected of SL interosseous ligament (SLIL) injuries were referred for further evaluation of chronic wrist pain (>3 months). Twelve wrists (11 subjects) with chronic symptoms and inconclusive plain radiographs and 10 asymptomatic wrists (in 10 different subjects) were scanned using 4DCT. The minimum SL interval was measured during three wrist motions: relaxed-to-clenched fist, flexion-to-extension, and radial-to-ulnar-deviation. Changes were recorded using double-oblique multiplanar reformation technique. We extracted the normal limits of the SL interval as measured by dynamic CT scanning during active motion in asymptomatic wrists. In asymptomatic wrists, the average SL interval was observed to be smaller than 1 mm during all motions. In symptomatic wrists, during exams performed with clenched fist (SL interval (mean ± SD) = 2.53 ± 1.19 mm), extension (2.54 ± 1.48 mm) or ulnar deviation (2.06 ± 1.12 mm), the average SL interval was more than 2 mm. In contrast to symptomatic wrists, no significant change in SL interval measurements was detected during wrist motions in asymptomatic wrists. There was a mild to moderate correlation between SL interval change and presence/absence of symptoms (point-biserial correlation coefficients: 0.29-0.55). In patients with wrist pain suspicious for SLIL injury and inconclusive radiographs, SL interval increase can be detected with 4DCT in the symptomatic wrist compared to the asymptomatic wrist. (orig.)

  8. Preliminary results of a four-dimensional data assimilation technique at a Mediterranean coastal area, Southern Italy

    Science.gov (United States)

    Avolio, E.; Federico, S.; Sempreviva, A. M.; Calidonna, C. R.; de Leo, L.; Bellecci, C.

    2010-09-01

    A four-dimensional data assimilation (FDDA) scheme based on a Newtonian relaxation (or "nudging") was tested using observational asynoptic data available at a coastal site in the Central Mediterranean peninsula of Calabria, in South Italy. Since nudging is performed toward observations, the technique is referred to as "observational data assimilation (ODA)" and it was incorporated into a tailored version of the Regional Atmospheric Modeling System (RAMS). This version of RAMS was run at high spatial horizontal resolution (1km), with the purpose of investigating the improvements of the model performance obtained by the assimilation. Wind profiler, sodar and surface meteorological station measurements were considered. In particular, we assimilated vertical wind profiles from the sodar and wind profiler, and wind, temperature and specific humidity from the surface meteorological station. All instruments are installed and operated routinely at the experimental field of the ISAC/CNR-CRATI located at 600 m from the Tyrrhenian coastline. A second station, located few kilometres to the NE of the experimental field, is considered as independent verification. The RAMS meteorological fields, simulated with and without data assimilation, were evaluated and compared for selected case studies in the summer 2008; several experiments were performed for each case (assimilation for the entire simulation time, and for different time windows). The results show that the assimilation of wind and/or temperature data, both throughout the simulation time (continuous FDDA) and for a 12h time window (forecasting configuration), produces improvements of the model performance. Improvements are substantial (50% error reduction) in the case of continuous FDDA, while they are reduced in the case of forecasting configuration (5% to 20% error reduction, depending on cases). The obtained meteorological fields are finalised as input into air quality and agro-meteorological models, and also for

  9. Micro-and nanodosimetry for radiobiological planning in radiotherapy and cancer risk assessment in radiation environment

    International Nuclear Information System (INIS)

    Full text: Microdosimetry and nanodosimetry can provide unique information for prediction of radiobiological properties of radiation, which is important in radiation therapy for accurate dose planning and in radiation protection for cancer induction risk assessment. This demand measurements of the pattern of energies deposited by ionizing radiation on cellular scale and DNA levels.Silicon microelectronics technology is offering a unique opportunity for replacing gas proportional counters (TEPC) with miniature detectors for regional microdosimetry. Silicon on Insulator (SOI) technology has been used for the development of arrays of micron size sensitive volumes for modelling energy deposited in biological cells. The challenge in silicon microdosimetry is the development of well defined sensitive volume (SV) and full charge collection deposited by ionizing radiation in the SV. First generation SOI microdosimeters were developed at CMRP and investigated in a wide range of radiation fields for proton and neutron therapies and recently on isotopic neutron sources and heavy ions with energy up to lGeV/jj,m which are typical for deep space radiation environment. Microdosimetric spectra were obtained in a phantom that are well matched to TEPC and Monte Carlo simulations. Evidence that radiations with the same LET exhibit different biological effects demand development of new sensors sensitive to the track structure of ions or the type of particle for prediction of radiobiological effect of radiation using radiobiological models. New monolithic Si AE-E telescope of cellular size for simultaneous regional microdosimetry and particle identification will be presented and results will be discussed. The new design of the SOI microdosimeter is based on 3D micron and submicron size of Si SVs. This approach allows improvement in the accuracy of the Si microdosimetry because of full charge collection and the ability to measure low LET as low as 0.01 keV/jjm, which is similar to TEPC

  10. Assessment of risks of stenosis of the anal canal during a prostatic radiotherapy; evaluation des risques de stenose du canal anal lors de la radiotherapie prostatique

    Energy Technology Data Exchange (ETDEWEB)

    Almokhles, H.; Pan, Q.; Calitchi, E.; Diana, C.; Muresan, M.; Jiang, M.W.; Wu, J.F.; Wang, X.W.; Lu, H.J.; Lagrange, J.L. [Hopital Henri-Mondor, Creteil (France)

    2011-10-15

    The authors report a study which aimed at assessing the late tolerance of a prostatic irradiation at the rectum and anal canal level. They assessed the length of the rectum and of the anal canal after prostate irradiation or surgery in patients who suffered from a prostate adenocarcinoma. Data of 154 patients have been analyzed regarding the number of cases of stenosis of rectum or anal canal. They highlight the importance of the irradiated length and dose level. Short communication

  11. Four-dimensional (4D) flow of the whole heart and great vessels using real-time respiratory self-gating

    DEFF Research Database (Denmark)

    Uribe, Sergio; Beerbaum, Philipp; Sørensen, Thomas Sangild;

    2009-01-01

    Four-dimensional (4D) flow imaging has been used to study flow patterns and pathophysiology, usually focused on specific thoracic vessels and cardiac chambers. Whole-heart 4D flow at high measurement accuracy covering the entire thoracic cardiovascular system would be desirable to simplify and im...

  12. On the one-loop effective potential in the higher-derivative four-dimensional chiral superfield theory with a nonconventional kinetic term

    International Nuclear Information System (INIS)

    We explicitly calculate the one-loop effective potential for a higher-derivative four-dimensional chiral superfield theory with a nonconventional kinetic term. We consider the cases of minimal and nonminimal general Lagrangians. In particular, we find that in the minimal case the divergent part of the one-loop effective potential vanishes by reason of the chirality.

  13. Interobserver agreement in detailed prenatal diagnosis of congenital heart disease by telemedicine using four-dimensional ultrasound with spatiotemporal image correlation

    NARCIS (Netherlands)

    Adriaanse, B.M.; Tromp, C.H.; Simpson, J.M.; Mieghem, T. van; Kist, W.J.; Kuik, D.J.; Oepkes, D.; Vugt, J.M. van; Haak, M.C.

    2012-01-01

    OBJECTIVE: To evaluate the clinical accuracy of four-dimensional (4D) echocardiography in the detailed prenatal diagnosis of congenital heart disease (CHD) in a telemedicine setting. METHODS: Ten second-trimester spatiotemporal image correlation (STIC) volumes were sent to three observers in differe

  14. USE OF FOUR-DIMENSIONAL DATA ASSIMILATION IN A LIMITED-AREA MESOSCALE MODEL - PART II: EFFECTS OF DATA ASSIMILATION WITHIN THE PLANETARY BOUNDARY LAYER

    Science.gov (United States)

    A four-dimensional data assimilation (FDDA) scheme based on Newtonian relaxation or nudging has been developed and evaluated in the Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR) Limited-Area Mesoscale Model. t was shown in Part I of this study ...

  15. To what extent does the anxiety scale of the Four-Dimensional Symptom Questionnaire (4DSQ) detect specific types of anxiety disorder in primary care? A psychometric study

    NARCIS (Netherlands)

    Terluin, B.; Oosterbaan, D.B.; Brouwers, E.P.; Straten, A. van; Ven, P.M. van de; Langerak, W.; Marwijk, H.W.J. van

    2014-01-01

    BACKGROUND: Anxiety scales may help primary care physicians to detect specific anxiety disorders among the many emotionally distressed patients presenting in primary care. The anxiety scale of the Four-Dimensional Symptom Questionnaire (4DSQ) consists of an admixture of symptoms of specific anxiety

  16. Quality of life assessment in advanced non-small-cell lung cancer patients undergoing an accelerated radiotherapy regimen: report of ECOG study 4593

    International Nuclear Information System (INIS)

    Purpose: To prospectively evaluate the quality of life (QOL) before, at completion, and after therapy for patients receiving an accelerated fractionation schedule of radiotherapy for advanced, unresectable non-small-cell lung cancer in a Phase II multi-institutional trial. Methods and Materials: The Functional Assessment of Cancer Therapy-Lung (FACT-L) patient questionnaire was used to score the QOL in patients enrolled in the Eastern Cooperative Oncology Group Phase II trial (ECOG 4593) of hyperfractionated accelerated radiotherapy in non-small-cell lung cancer. Radiotherapy (total dose 57.6 Gy in 36 fractions) was delivered during 15 days, with three radiation fractions given each treatment day. The protocol was activated in 1993, and 30 patients had accrued by November 1995. The FACT-L questionnaire was administered at study entry (baseline), on the last day of radiotherapy (assessment 2), and 4 weeks after therapy (assessment 3). The FACT-L includes scores for physical, functional, emotional, and social well-being (33 items), and a subscale of lung cancer symptoms (10 additional items). The summation of the physical, functional, and lung cancer symptom subscales (21 items) constitutes the Trial Outcome Index (TOI), considered the most clinically relevant outcome measure in lung cancer treatment trials. Results: The FACT-L completion rates at the designated study time points were as follows: baseline, 30 of 30 (100%); assessment 2, 29 (97%) of 30; and assessment 3, 24 (80%) of 30. At treatment completion, statistically significant declines in QOL scores were noted, compared with baseline for physical and functional well-being. Emotional well-being scores improved at both assessment 2 and assessment 3. The physical and functional scores returned approximately to baseline values at assessment 3. The change in TOI score was evaluated as a function of the clinical response to treatment, toxicity grade, and survival; no clear association was noted. A trend for the

  17. Radiotherapy for craniopharyngioma.

    Science.gov (United States)

    Aggarwal, Ajay; Fersht, Naomi; Brada, Michael

    2013-03-01

    Radiotherapy remains the mainstay of multidisciplinary management of patients with incompletely resected and recurrent craniopharyngioma. Advances in imaging and radiotherapy technology offer new alternatives with the principal aim of improving the accuracy of treatment and reducing the volume of normal brain receiving significant radiation doses. We review the available technologies, their technical advantages and disadvantages and the published clinical results. Fractionated high precision conformal radiotherapy with image guidance remains the gold standard; the results of single fraction treatment are disappointing and hypofractionation should be used with caution as long term results are not available. There is insufficient data on the use of protons to assess the comparative efficacy and toxicity. The precision of treatment delivery needs to be coupled with experienced infrastructure and more intensive quality assurance to ensure best treatment outcome and this should be carried out within multidisciplinary teams experienced in the management of craniopharyngioma. The advantages of the combined skills and expertise of the team members may outweigh the largely undefined clinical gain from novel radiotherapy technologies.

  18. SU-C-207-01: Four-Dimensional Inverse Geometry Computed Tomography: Concept and Its Validation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K; Kim, D; Kim, T; Kang, S; Cho, M; Shin, D; Suh, T [The Catholic University of Korea, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: In past few years, the inverse geometry computed tomography (IGCT) system has been developed to overcome shortcomings of a conventional computed tomography (CT) system such as scatter problem induced from large detector size and cone-beam artifact. In this study, we intend to present a concept of a four-dimensional (4D) IGCT system that has positive aspects above all with temporal resolution for dynamic studies and reduction of motion artifact. Methods: Contrary to conventional CT system, projection data at a certain angle in IGCT was a group of fractionated narrow cone-beam projection data, projection group (PG), acquired from multi-source array which have extremely short time gap of sequential operation between each of sources. At this, for 4D IGCT imaging, time-related data acquisition parameters were determined by combining multi-source scanning time for collecting one PG with conventional 4D CBCT data acquisition sequence. Over a gantry rotation, acquired PGs from multi-source array were tagged time and angle for 4D image reconstruction. Acquired PGs were sorted into 10 phase and image reconstructions were independently performed at each phase. Image reconstruction algorithm based upon filtered-backprojection was used in this study. Results: The 4D IGCT had uniform image without cone-beam artifact on the contrary to 4D CBCT image. In addition, the 4D IGCT images of each phase had no significant artifact induced from motion compared with 3D CT. Conclusion: The 4D IGCT image seems to give relatively accurate dynamic information of patient anatomy based on the results were more endurable than 3D CT about motion artifact. From this, it will be useful for dynamic study and respiratory-correlated radiation therapy. This work was supported by the Industrial R&D program of MOTIE/KEIT [10048997, Development of the core technology for integrated therapy devices based on real-time MRI guided tumor tracking] and the Mid-career Researcher Program (2014R1A2A1A

  19. Improving thoracic four-dimensional cone-beam CT reconstruction with anatomical-adaptive image regularization (AAIR)

    Science.gov (United States)

    Shieh, Chun-Chien; Kipritidis, John; O'Brien, Ricky T.; Cooper, Benjamin J.; Kuncic, Zdenka; Keall, Paul J.

    2015-01-01

    Total-variation (TV) minimization reconstructions can significantly reduce noise and streaks in thoracic four-dimensional cone-beam computed tomography (4D CBCT) images compared to the Feldkamp-Davis-Kress (FDK) algorithm currently used in practice. TV minimization reconstructions are, however, prone to over-smoothing anatomical details and are also computationally inefficient. The aim of this study is to demonstrate a proof of concept that these disadvantages can be overcome by incorporating the general knowledge of the thoracic anatomy via anatomy segmentation into the reconstruction. The proposed method, referred as the anatomical-adaptive image regularization (AAIR) method, utilizes the adaptive-steepest-descent projection-onto-convex-sets (ASD-POCS) framework, but introduces an additional anatomy segmentation step in every iteration. The anatomy segmentation information is implemented in the reconstruction using a heuristic approach to adaptively suppress over-smoothing at anatomical structures of interest. The performance of AAIR depends on parameters describing the weighting of the anatomy segmentation prior and segmentation threshold values. A sensitivity study revealed that the reconstruction outcome is not sensitive to these parameters as long as they are chosen within a suitable range. AAIR was validated using a digital phantom and a patient scan and was compared to FDK, ASD-POCS and the prior image constrained compressed sensing (PICCS) method. For the phantom case, AAIR reconstruction was quantitatively shown to be the most accurate as indicated by the mean absolute difference and the structural similarity index. For the patient case, AAIR resulted in the highest signal-to-noise ratio (i.e. the lowest level of noise and streaking) and the highest contrast-to-noise ratios for the tumor and the bony anatomy (i.e. the best visibility of anatomical details). Overall, AAIR was much less prone to over-smoothing anatomical details compared to ASD-POCS and did

  20. Four-dimensional distribution of the 2010 Eyjafjallajökull volcanic cloud over Europe observed by EARLINET

    Directory of Open Access Journals (Sweden)

    G. Pappalardo

    2013-04-01

    Full Text Available The eruption of the Icelandic volcano Eyjafjallajökull in April–May 2010 represents a "natural experiment" to study the impact of volcanic emissions on a continental scale. For the first time, quantitative data about the presence, altitude, and layering of the volcanic cloud, in conjunction with optical information, are available for most parts of Europe derived from the observations by the European Aerosol Research Lidar NETwork (EARLINET. Based on multi-wavelength Raman lidar systems, EARLINET is the only instrument worldwide that is able to provide dense time series of high-quality optical data to be used for aerosol typing and for the retrieval of particle microphysical properties as a function of altitude. In this work we show the four-dimensional (4-D distribution of the Eyjafjallajökull volcanic cloud in the troposphere over Europe as observed by EARLINET during the entire volcanic event (15 April–26 May 2010. All optical properties directly measured (backscatter, extinction, and particle linear depolarization ratio are stored in the EARLINET database available at http://www.earlinet.org. A specific relational database providing the volcanic mask over Europe, realized ad hoc for this specific event, has been developed and is available on request at http://www.earlinet.org. During the first days after the eruption, volcanic particles were detected over Central Europe within a wide range of altitudes, from the upper troposphere down to the local planetary boundary layer (PBL. After 19 April 2010, volcanic particles were detected over southern and south-eastern Europe. During the first half of May (5–15 May, material emitted by the Eyjafjallajökull volcano was detected over Spain and Portugal and then over the Mediterranean and the Balkans. The last observations of the event were recorded until 25 May in Central Europe and in the Eastern Mediterranean area. The 4-D distribution of volcanic aerosol layering and optical properties on

  1. Four-dimensional distribution of the 2010 Eyjafjallajökull volcanic cloud over Europe observed by EARLINET

    Directory of Open Access Journals (Sweden)

    G. Pappalardo

    2012-11-01

    Full Text Available The eruption of the Icelandic volcano Eyjafjallajökull in April/May 2010 represents a "natural experiment" to study the impact of volcanic emissions on a continental scale. For the first time, quantitative data about the presence, altitude, and layering of the volcanic cloud, in conjunction with optical information, are available for most parts of Europe derived from the observations by the European Aerosol Research Lidar NETwork (EARLINET. Based on multi-wavelength Raman lidar systems EARLINET is the only instrument worldwide that is able to provide dense time series of high-quality optical data to be used for aerosol typing and for the retrieval of particle microphysical properties as a function of altitude.

    In this work we show the four-dimensional (4-D distribution of the Eyjafjallajökull volcanic cloud over Europe as observed by EARLINET during the entire volcanic event (15 April–26 May 2010. All optical properties directly measured (backscatter, extinction, and particle linear depolarization ratio are stored in the EARLINET database available at http://www.earlinet.org. A specific relational database providing the volcanic mask over Europe, realized ad hoc for this specific event, has been developed and is available on request at http://www.earlinet.org.

    During the first days after the eruption, volcanic particles were detected over Central Europe within a wide range of altitudes, from the lower stratosphere down to the local Planetary Boundary Layer (PBL. After 19 April 2010, volcanic particles were detected over South and South Eastern Europe. During the first half of May (5–15 May, material emitted by the Eyjafjallajökull volcano was detected over Spain and Portugal and then over the Mediterranean and the Balkans. Last observations of the event were recorded until 25 May in Central Europe and in the Eastern

  2. Improving thoracic four-dimensional cone-beam CT reconstruction with anatomical-adaptive image regularization (AAIR)

    International Nuclear Information System (INIS)

    Total-variation (TV) minimization reconstructions can significantly reduce noise and streaks in thoracic four-dimensional cone-beam computed tomography (4D CBCT) images compared to the Feldkamp–Davis–Kress (FDK) algorithm currently used in practice. TV minimization reconstructions are, however, prone to over-smoothing anatomical details and are also computationally inefficient. The aim of this study is to demonstrate a proof of concept that these disadvantages can be overcome by incorporating the general knowledge of the thoracic anatomy via anatomy segmentation into the reconstruction. The proposed method, referred as the anatomical-adaptive image regularization (AAIR) method, utilizes the adaptive-steepest-descent projection-onto-convex-sets (ASD-POCS) framework, but introduces an additional anatomy segmentation step in every iteration. The anatomy segmentation information is implemented in the reconstruction using a heuristic approach to adaptively suppress over-smoothing at anatomical structures of interest. The performance of AAIR depends on parameters describing the weighting of the anatomy segmentation prior and segmentation threshold values. A sensitivity study revealed that the reconstruction outcome is not sensitive to these parameters as long as they are chosen within a suitable range. AAIR was validated using a digital phantom and a patient scan and was compared to FDK, ASD-POCS and the prior image constrained compressed sensing (PICCS) method. For the phantom case, AAIR reconstruction was quantitatively shown to be the most accurate as indicated by the mean absolute difference and the structural similarity index. For the patient case, AAIR resulted in the highest signal-to-noise ratio (i.e. the lowest level of noise and streaking) and the highest contrast-to-noise ratios for the tumor and the bony anatomy (i.e. the best visibility of anatomical details). Overall, AAIR was much less prone to over-smoothing anatomical details compared to ASD-POCS and

  3. Assessment of two novel ventilatory surrogates for use in the delivery of gated/tracked radiotherapy for non-small cell lung cancer

    International Nuclear Information System (INIS)

    Background: In selected patients with NSCLC the therapeutic index of radical radiotherapy can be improved with gating/tracking technology. Both techniques require real-time information on target location. This is often derived from a surrogate ventilatory signal. We assessed the correlation of two novel surrogate ventilatory signals with a spirometer-derived signal. The novel signals were obtained using the VisionRT stereoscopic camera system. The VisionRT-Tracked-Point (VRT-TP) signal was derived from tracking a point located midway between the umbilicus and xiphisternum. The VisionRT-Surface-Derived-Volume (VRT-SDV) signal was derived from 3D body surface imaging of the torso. Both have potential advantages over the current surrogate signals. Methods: Eleven subjects with NSCLC were recruited. Each was positioned as for radiotherapy treatment, and then instructed to breathe in five different modes: normal, abdominal, thoracic, deep and shallow breathing. Synchronous ventilatory signals were recorded for later analysis. The signals were analysed for correlation across all modes of breathing, and phase shifts. The VRT-SDV was also assessed for its ability to determine the mode of breathing. Results: Both novel respiratory signals showed good correlation (r > 0.80) with spirometry in 9 of 11 subjects. For all subjects the correlation with spirometry was better for the VRT-SDV signal than for the VRT-TP signal. Only one subject displayed a phase shift between the VisionRT-derived signals and spirometry. The VRT-SDV signal could also differentiate between different modes of breathing. Unlike the spirometer-derived signal, neither VisionRT-derived signal was subject to drift. Conclusion: Both the VRT-TP and VRT-SDV signals have potential applications in ventilatory-gated and tracked radiotherapy. They can also be used as a signal for sorting 4DCT images, and to drive 4DCT single- and multiple-parameter motion models.

  4. Tumor Shrinkage Assessed by Volumetric MRI in Long-Term Follow-Up After Fractionated Stereotactic Radiotherapy of Nonfunctioning Pituitary Adenoma

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, Christine, E-mail: Christine.Kopp@lrz.tu-muenchen.de [Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich (Germany); Theodorou, Marilena; Poullos, Nektarios; Jacob, Vesna; Astner, Sabrina T.; Molls, Michael [Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich (Germany); Grosu, Anca-Ligia [Klinik fuer Strahlenheilkunde, Universitaet Freiburg, Freiburg (Germany)

    2012-03-01

    Purpose: To evaluate tumor control and side effects associated with fractionated stereotactic radiotherapy (FSRT) in the management of residual or recurrent nonfunctioning pituitary adenomas (NFPAs). Methods and Materials: We assessed exact tumor volume shrinkage in 16 patients with NFPA after FSRT. All patients had previously undergone surgery. Gross tumor volume (GTV) was outlined on contrast-enhanced magnetic resonance imaging (MRI) before and median 63 months (range, 28-100 months) after FSRT. MRI was performed as an axial three-dimensional gradient echo T1-weighted sequence at 1.6-mm slice thickness without gap (3D MRI). Results: Mean tumor size of all 16 pituitary adenomas before treatment was 7.4 mL (3.3-18.9 mL). We found shrinkage of the treated pituitary adenoma in all patients. Within a median follow-up of 63 months (28-100 months) an absolute mean volume reduction of 3.8 mL (0.9-12.4 mL) was seen. The mean relative size reduction compared with the volume before radiotherapy was 51% (22%-95%). Shrinkage measured by 3D MRI was greater at longer time intervals after radiotherapy. A strong negative correlation between the initial tumor volume and the absolute volume reduction after FSRT was found. There was no correlation between tumor size reduction and patient age, sex, or number of previous surgeries. Conclusions: By using 3D MRI in all patients undergoing FSRT of an NFPA, tumor shrinkage is detected. Our data demonstrate that volumetric assessment based on 3D MRI adds additional information to routinely used radiological response measurements. After FSRT a mean relative size reduction of 51% can be expected within 5 years.

  5. Tumor Shrinkage Assessed by Volumetric MRI in Long-Term Follow-Up After Fractionated Stereotactic Radiotherapy of Nonfunctioning Pituitary Adenoma

    International Nuclear Information System (INIS)

    Purpose: To evaluate tumor control and side effects associated with fractionated stereotactic radiotherapy (FSRT) in the management of residual or recurrent nonfunctioning pituitary adenomas (NFPAs). Methods and Materials: We assessed exact tumor volume shrinkage in 16 patients with NFPA after FSRT. All patients had previously undergone surgery. Gross tumor volume (GTV) was outlined on contrast-enhanced magnetic resonance imaging (MRI) before and median 63 months (range, 28–100 months) after FSRT. MRI was performed as an axial three-dimensional gradient echo T1-weighted sequence at 1.6-mm slice thickness without gap (3D MRI). Results: Mean tumor size of all 16 pituitary adenomas before treatment was 7.4 mL (3.3–18.9 mL). We found shrinkage of the treated pituitary adenoma in all patients. Within a median follow-up of 63 months (28–100 months) an absolute mean volume reduction of 3.8 mL (0.9–12.4 mL) was seen. The mean relative size reduction compared with the volume before radiotherapy was 51% (22%–95%). Shrinkage measured by 3D MRI was greater at longer time intervals after radiotherapy. A strong negative correlation between the initial tumor volume and the absolute volume reduction after FSRT was found. There was no correlation between tumor size reduction and patient age, sex, or number of previous surgeries. Conclusions: By using 3D MRI in all patients undergoing FSRT of an NFPA, tumor shrinkage is detected. Our data demonstrate that volumetric assessment based on 3D MRI adds additional information to routinely used radiological response measurements. After FSRT a mean relative size reduction of 51% can be expected within 5 years.

  6. Radiotherapy in a public health

    International Nuclear Information System (INIS)

    The aim of our publication is to evaluate the state of radiotherapy, its role and place in oncology and in the public health system, in order to plan necessities. The cost and economical effectiveness are objectives of the current evaluation. Radiotherapy is strongly dependant of introducing new technologies and the need of gross capital investments. However, their relative cost is reduced due to their long-term use. Because of the serious delay of Bulgaria from the world standards in radiotherapy, the analysis is based on the data published in the scientific literature. The main tendencies and ideas for development are based on the analysis of The Swedish Council on Technology Assessment in Health Care (SBU) and the ESTRO QUARTS project. We use Swedish model for estimating the expenses, having in mind the conditions in Bulgaria (salary, management, patient cares). The main conclusions are: 1) Radiotherapy is basic curative and palliative method in oncology; 2) Bulgarian radiotherapy is at one of the last places in Europe (therapeutic units are 30 years old average, despite their recommended exploitation of 12-20 years); 3) In contradiction to the world tendencies delay grows during the last 10 years; 4) In countries with low or average GDP radiotherapy should be prioritized, due to its low cost in comparison to the other treatment methods in oncology; 5) The need of radiotherapy will continue to grow, this necessitate not only replacement of the old machines but increasing their number 3 times during the next few years; 6) It is necessary to form a modern radiotherapy centers, equipped with at least two compatible units, based on the currently existing radiotherapy departments. (authors)

  7. Application of alanine dosimetry in dose assessment for ocular melanoma patients undergoing proton radiotherapy – preliminary results

    Directory of Open Access Journals (Sweden)

    Mierzwińska Gabriela

    2015-09-01

    Full Text Available Basing on alanine solid state/electron paramagnetic resonance (EPR dosimetry, a supplementary method of cumulatively recording the therapeutic dose received by ocular cancer patients undergoing fractionated proton radiotherapy is proposed. By applying alanine dosimetry during the delivery of consecutive fractions, the dose received within each fraction can be read out by EPR spectrometry and a final permanent cumulative record of the total dose delivered obtained. The dose response of the alanine detector was found to be practically independent on its position within the extended proton Bragg peak region. Dose measurements based on entrance dose recorded in proton beams individually formed for each patient are presented. The described method will be applied as a complementary Quality Assurance procedure for patients undergoing proton radiotherapy at the Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland (IFJ PAN.

  8. Quality improvement process to assess tattoo alignment, set-up accuracy and isocentre reproducibility in pelvic radiotherapy patients

    OpenAIRE

    Elsner, Kelly; Francis, Kate; Hruby, George; Roderick, Stephanie

    2014-01-01

    Introduction This quality improvement study tested three methods of tattoo alignment and isocentre definition to investigate if aligning lateral tattoos to minimise pitch, roll and yaw decreased set-up error, and if defining the isocentre using the lateral tattoos for cranio-caudal (CC) position improved isocentre reproducibility. The study population was patients receiving curative external beam radiotherapy (EBRT) for prostate cancer. The results are applicable to all supine pelvic EBRT pat...

  9. Measuring interfraction and intrafraction lung function changes during radiation therapy using four-dimensional cone beam CT ventilation imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kipritidis, John, E-mail: john.kipritidis@sydney.edu.au; Keall, Paul J. [Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney NSW 2006 (Australia); Hugo, Geoffrey; Weiss, Elisabeth; Williamson, Jeffrey [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2015-03-15

    Purpose: Adaptive ventilation guided radiation therapy could minimize the irradiation of healthy lung based on repeat lung ventilation imaging (VI) during treatment. However the efficacy of adaptive ventilation guidance requires that interfraction (e.g., week-to-week), ventilation changes are not washed out by intrafraction (e.g., pre- and postfraction) changes, for example, due to patient breathing variability. The authors hypothesize that patients undergoing lung cancer radiation therapy exhibit larger interfraction ventilation changes compared to intrafraction function changes. To test this, the authors perform the first comparison of interfraction and intrafraction lung VI pairs using four-dimensional cone beam CT ventilation imaging (4D-CBCT VI), a novel technique for functional lung imaging. Methods: The authors analyzed a total of 215 4D-CBCT scans acquired for 19 locally advanced non-small cell lung cancer (LA-NSCLC) patients over 4–6 weeks of radiation therapy. This set of 215 scans was sorted into 56 interfraction pairs (including first day scans and each of treatment weeks 2, 4, and 6) and 78 intrafraction pairs (including pre/postfraction scans on the same-day), with some scans appearing in both sets. VIs were obtained from the Jacobian determinant of the transform between the 4D-CBCT end-exhale and end-inhale images after deformable image registration. All VIs were deformably registered to their corresponding planning CT and normalized to account for differences in breathing effort, thus facilitating image comparison in terms of (i) voxelwise Spearman correlations, (ii) mean image differences, and (iii) gamma pass rates for all interfraction and intrafraction VI pairs. For the side of the lung ipsilateral to the tumor, we applied two-sided t-tests to determine whether interfraction VI pairs were more different than intrafraction VI pairs. Results: The (mean ± standard deviation) Spearman correlation for interfraction VI pairs was r{sup -}{sub Inter

  10. Comparison of planning target volumes based on three-dimensional and four-dimensional CT imaging of thoracic esophageal cancer

    Directory of Open Access Journals (Sweden)

    Wang W

    2016-08-01

    Full Text Available Wei Wang, Jianbin Li, Yingjie Zhang, Qian Shao, Min Xu, Tingyong Fan, Jinzhi Wang Department of Radiation Oncology, Shandong Cancer Hospital Affiliated to Shandong University, Shandong Academy of Medical Sciences, Shandong, People’s Republic of China Background and purpose: To investigate the definition of planning target volumes (PTVs based on four-dimensional computed tomography (4DCT compared with conventional PTV definition and PTV definition using asymmetrical margins for thoracic primary esophageal cancer. Materials and methods: Forty-three patients with esophageal cancer underwent 3DCT and 4DCT simulation scans during free breathing. The motions of primary tumors located in the proximal (group A, middle (group B, and distal (group C thoracic esophagus were obtained from the 4DCT scans. PTV3D was defined on 3DCT using the tumor motion measured based on 4DCT, PTV conventional (PTVconv was defined on 3DCT by adding a 1.0 cm margin to the clinical target volume, and PTV4D was defined as the union of the target volumes contoured on the ten phases of the 4DCT images. The centroid positions, volumetric differences, and dice similarity coefficients were evaluated for all PTVs. Results: The median centroid shifts between PTV3D and PTV4D and between PTVconv and PTV4D in all three dimensions were <0.3 cm for the three groups. The median size ratios of PTV4D to PTV3D were 0.80, 0.88, and 0.71, and PTV4D to PTVconv were 0.67, 0.73, and 0.76 (χ2=–3.18, –2.98, and –3.06; P=0.001, 0.003, and 0.002 for groups A, B, and C, respectively. The dice similarity coefficients were 0.87, 0.90, and 0.81 between PTV4D and PTV3D and 0.80, 0.84, and 0.83 between PTV4D and PTVconv (χ2=–3.18, –2.98, and –3.06; P=0.001, 0.003, and 0.002 for groups A, B, and C, respectively. The difference between the degree of inclusion of PTV4D in PTV3D and that of PTV4D in PTVconv was <2% for all groups. Compared with PTVconv, the amount of irradiated normal tissue

  11. Comparative study and clinical implementation of two breathing-adapted radiotherapy techniques: dosimetric benefits for lung cancer treatment; Etude comparative et mise en oeuvre clinique de deux systemes de radiotherapie asservie a la respiration: benefice dosimetrique pour le traitement du cancer du poumon

    Energy Technology Data Exchange (ETDEWEB)

    Simon, L.; Giraud, P.; Rosenwald, J.C. [Institut Curie, Dept. de Radiotherapie, 75 - Paris (France); Servois, V. [Institut Curie, Dept. d' Imagerie Medicale, 75 - Paris (France)

    2006-11-15

    Breathing can lead to organ motions up to several centimeters. For radiotherapy of lung, these motions are generally taken into account by adding a specific margin around the target. Thus, treated volumes are often too large to allow for the high-dose values requested for local control. To manage respiratory motion, deep-inspiration breath-hold technique (DIBH) and gated radiotherapy are starting being used clinically. DIBH consists in asking the patient to perform breath-hold during the treatment and the image acquisition, DIBH level being measured by a spirometer. Gated radiotherapy consists in treating the patient at a certain phase of the free breathing. Linac is synchronized with the motion of a marker' located on the patient chest. Planning images are obtained by a four-dimensional CT (4D-CT) using the same marker. We have assessed the value of these two methods. For lung treatment, compared to a standard treatment, toxicity reduction was mainly due to the lung total volume increase.; It is therefore more significant for breath-hold approach. It is also due to the reduction of safety margins, which is similar for both methods. These two techniques, which have specific advantages and drawbacks, are used routinely at Curie Institute for a large proportion of lung patients, but also for some breast, liver or even Hodgkin disease treatments. (author)

  12. Evaluation of novel radiotherapy technologies: what evidence is needed to assess their clinical and cost effectiveness, and how should we get it?

    NARCIS (Netherlands)

    Loon, J. van; Grutters, J.P.C.; Macbeth, F.

    2012-01-01

    Technical innovations in radiation oncology--eg, intensity-modulated radiotherapy, stereotactic radiotherapy, and particle therapy--can be developed rapidly and introduced into the clinic even when costs associated with their use are much higher than those for conventional radiotherapy. Although cli

  13. Continuous table acquisition MRI for radiotherapy treatment planning: Distortion assessment with a new extended 3D volumetric phantom

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Amy, E-mail: aw554@uowmail.edu.au; Metcalfe, Peter [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia and Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170 (Australia); Liney, Gary [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170 (Australia); South West Clinical School, University of New South Wales, Sydney, NSW 2170 (Australia); Holloway, Lois [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170 (Australia); South West Clinical School, University of New South Wales, Sydney, NSW 2170 (Australia); Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Dowling, Jason; Rivest-Henault, David [Commonwealth Scientific and Industrial Research Organisation, Australian E-Health Research Centre, Herston, QLD 4029 (Australia)

    2015-04-15

    Purpose: Accurate geometry is required for radiotherapy treatment planning (RTP). When considering the use of magnetic resonance imaging (MRI) for RTP, geometric distortions observed in the acquired images should be considered. While scanner technology and vendor supplied correction algorithms provide some correction, large distortions are still present in images, even when considering considerably smaller scan lengths than those typically acquired with CT in conventional RTP. This study investigates MRI acquisition with a moving table compared with static scans for potential geometric benefits for RTP. Methods: A full field of view (FOV) phantom (diameter 500 mm; length 513 mm) was developed for measuring geometric distortions in MR images over volumes pertinent to RTP. The phantom consisted of layers of refined plastic within which vitamin E capsules were inserted. The phantom was scanned on CT to provide the geometric gold standard and on MRI, with differences in capsule location determining the distortion. MRI images were acquired with two techniques. For the first method, standard static table acquisitions were considered. Both 2D and 3D acquisition techniques were investigated. With the second technique, images were acquired with a moving table. The same sequence was acquired with a static table and then with table speeds of 1.1 mm/s and 2 mm/s. All of the MR images acquired were registered to the CT dataset using a deformable B-spline registration with the resulting deformation fields providing the distortion information for each acquisition. Results: MR images acquired with the moving table enabled imaging of the whole phantom length while images acquired with a static table were only able to image 50%–70% of the phantom length of 513 mm. Maximum distortion values were reduced across a larger volume when imaging with a moving table. Increased table speed resulted in a larger contribution of distortion from gradient nonlinearities in the through

  14. Rotationally acquired four-dimensional optical coherence tomography of embryonic chick hearts using retrospective gating on the common central A-scan

    DEFF Research Database (Denmark)

    Happel, Christoph M.; Thommes, Jan; Thrane, Lars;

    2011-01-01

    We introduce a new method of rotational image acquisition for four-dimensional (4D) optical coherence tomography (OCT) of beating embryonic chick hearts. The rotational axis and the central A-scan of the OCT are identical. An out-of-phase image sequence covering multiple heartbeats is acquired at.......We demonstrate this approach and provide a video of a beating Hamburger and Hamilton stage 16 embryonic chick heart generated from a 4D OCT data set using rotational image acquisition....

  15. Correlations of third-trimester hiatal biometry obtained using four-dimensional translabial ultrasonography with the delivery route in nulliparous pregnant women

    OpenAIRE

    Teerayut Temtanakitpaisan; Varisara Chantarasorn; Suvit Bunyavejchevin

    2015-01-01

    Purpose: The goal of this study was to evaluate normal hiatal dimensions in the third trimester in nulliparous Thai pregnant women and to establish which biometric factors were associated with various pregnancy outcomes. Methods: Fifty-seven consecutive nulliparous pregnant Thai women in their third trimester were recruited on a voluntary basis from April to October 2014. All subjects underwent four-dimensional (4D) translabial ultrasonography. Hiatal biometric parameters were measured at res...

  16. Quantum corrections to ward identities of chronological AVV- and AAA-current correlators for nondegenerate many-fermion systems in the four-dimensional world

    International Nuclear Information System (INIS)

    The explicit form of nontrivial quantum corrections to Ward identities for AVV- and AAA-current correlators in the four-dimensional world for nondegenerate many-fermion systems of general type is obtained. The characteristics of all nontrivial quantum corrections for nondegenerate two-flavour fermion systems are classified and described. In particular, the well-known results follow from ours for the trivial quantum corrections (anomalies) in the case of the degenerate spectrum of fermion masses

  17. To what extent does the anxiety scale of the Four-Dimensional Symptom Questionnaire (4DSQ) detect specific types of anxiety disorder in primary care? A psychometric study

    OpenAIRE

    Terluin, B.; Oosterbaan, D.B.; Brouwers, E.P.M.; van Straten, A.H.M.; Van de Ven, P.; Langerak, W.; van Marwijk, H.W.J.

    2014-01-01

    BACKGROUND: Anxiety scales may help primary care physicians to detect specific anxiety disorders among the many emotionally distressed patients presenting in primary care. The anxiety scale of the Four-Dimensional Symptom Questionnaire (4DSQ) consists of an admixture of symptoms of specific anxiety disorders. The research questions were: (1) Is the anxiety scale unidimensional or multidimensional? (2) To what extent does the anxiety scale detect specific DSM-IV anxiety disorders? (3) Which cu...

  18. TU-F-17A-09: Four-Dimensional Cone Beam CT Ventilation Imaging Can Detect Interfraction Lung Function Variations for Locally Advanced Lung Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Kipritidis, J; Keall, P [Radiation Physics Laboratory, University of Sydney, Sydney NSW 2006 Australia (Australia); Hugo, G; Weiss, E; Williamson, J [Department of Radiation Oncology, Virginia Commonwealth University, Richmond VA (United States)

    2014-06-15

    Purpose: Four-dimensional cone beam CT ventilation imaging (4D-CBCT VI) is a novel functional lung imaging modality requiring validation. We hypothesize that 4D-CBCT VI satisfies a necessary condition for validity: that intrafraction variations (e.g. due to poor 4D-CBCT image quality) are substantially different to interfraction variations (e.g. due to changes in underlying function). We perform the first comparison of intrafraction (pre/post fraction) and interfraction (week-to-week) 4D-CBCT VIs for locally advanced non small cell lung cancer (LA NSCLC) patients undergoing radiation therapy. Methods: A total of 215 4D-CBCT scans were acquired for 19 LA NSCLC patients over 4-6 weeks of radiation therapy, including 75 pairs of pre-/post-fraction scans on the same day. 4D-CBCT VIs were obtained by applying state-of-the-art, B-spline deformable image registration to obtain the Jacobian determinant of deformation between the end-exhale and end-inhale phases. All VIs were deformably registered to the corresponding first day scan, normalized between the 10th and 90th percentile values and cropped to the ipsilateral lung only. Intrafraction variations were assessed by computing the mean and standard deviation of voxel-wise differences between all same-day pairs of pre-/post-fraction VIs. Interfraction differences were computed between first-day VIs and treatment weeks 2, 4 and 6 for all 19 patients. We tested the hypothesis by comparing cumulative distribution functions (CDFs) of intrafraction and interfraction ventilation differences using two-sided Kolmogorov-Smirnov goodness-of-fit tests. Results: The (mean ± std. dev.) of intrafraction differences was (−0.007 ± 0.079). Interfraction differences for weeks 2, 4 and 6 were (−0.035 ± 0.103), (−0.006 ± 0.094) and (−0.019 ± 0.127) respectively. For week 2, the changes in CDFs for intrafraction and interfraction differences approached statistical significance (p=0.099). Conclusion: We have shown that 4D-CBCT VI

  19. New Visualization Techniques to Analyze Ultra-High Resolution Three- and Four-Dimensional Airborne and Tripod LiDAR Point-Cloud Data

    Science.gov (United States)

    Kreylos, O.; Bawden, G. W.; Kellogg, L. H.

    2007-12-01

    In the context of the UC~Davis W. M. Keck Center for Active Visualization in the Earth Sciences (KeckCAVES, http://www.keckcaves.org), we are developing an immersive visualization application to display and interact with very large (billions of points) three- and four-dimensional point-position datasets, such that point groups from repeated airborne and ground based Light Detection And Ranging (LiDAR) surveys can be selected, measured, and analyzed for quality control and land surface change detection. One of the difficulties of analyzing dense 3D and 4D point-cloud data is that there are few software packages that can display and analyze the data at full resolution and in the natural 3D perspective in which it was collected. We developed an octree-based, multiresolution, point-set data representation that allows very large point cloud datasets to be displayed at the frame rates required to create immersion (between 60 Hz and 120 Hz). Data inside an observer's region of interest is shown in full detail, whereas data outside the field of view or far away from the observer is shown at reduced resolution to provide context. Users can navigate LiDAR data sets and accurately select related point groups in two or more point sets by sweeping space using 3D input devices provided by immersive display environments such as CAVEs. Users can then guide the software in deriving positional information from point groups to compute displacements between surveys, or to extract survey measurements. This software runs on UNIX-like operating systems and can be used on laptop or desktop computers, 3D display systems such as Geowalls, and in fully immersive environments such as CAVEs. It is available for download from http://www.keckcaves.org. Examples of the wide range of applications of the software for airborne and Tripod LiDAR (T-LiDAR) include: 1)~visualization of airborne LiDAR data from the southern San Andreas Fault; 2)~quality control assessment of ground based T-LiDAR from the

  20. Assessment of contrast enhanced respiration managed cone-beam CT for image guided radiotherapy of intrahepatic tumors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Nikolaj K. G., E-mail: nkyj@regionsjaelland.dk [Physics and Engineering, London Regional Cancer Program, London, Ontario N6A3K7 (Canada); Stewart, Errol [Radiology, St. Joseph' s Health Care, London, Ontario N6A 4V2 (Canada); Imaging Research Lab, Robarts Research Institute, London, Ontario N6A 5B7 (Canada); Imaging Program, Lawson Health Research Institute, London, Ontario N6C 2R5 (Canada); Lock, Michael; Fisher, Barbara [Radiation Oncology, London Regional Cancer Program, London, Ontario N6A3K7 (Canada); Department of Oncology, University of Western Ontario, London, Ontario N6A 4L6 (Canada); Kozak, Roman [Radiology, St. Joseph' s Health Care, London, Ontario N6A 4V2 (Canada); Chen, Jeff [Physics and Engineering, London Regional Cancer Program, London, Ontario N6A3K7 (Canada); Department of Oncology, University of Western Ontario, London, Ontario N6A 4L6 (Canada); Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 5C1 (Canada); Lee, Ting-Yim [Radiology, St. Joseph' s Health Care, London, Ontario N6A 4V2 (Canada); Imaging Research Lab, Robarts Research Institute, London, Ontario N6A 5B7 (Canada); Imaging Program, Lawson Health Research Institute, London, Ontario N6C 2R5 (Canada); Department of Oncology, University of Western Ontario, London, Ontario N6A 4L6 (Canada); Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 5C1 (Canada); Wong, Eugene [Physics and Engineering, London Regional Cancer Program, London, Ontario N6A3K7 (Canada); Department of Oncology, University of Western Ontario, London, Ontario N6A 4L6 (Canada); Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 5C1 (Canada); Department of Physics and Astronomy, University of Western Ontario, London, Ontario N6A 3K7 (Canada)

    2014-05-15

    Purpose: Contrast enhancement and respiration management are widely used during image acquisition for radiotherapy treatment planning of liver tumors along with respiration management at the treatment unit. However, neither respiration management nor intravenous contrast is commonly used during cone-beam CT (CBCT) image acquisition for alignment prior to radiotherapy. In this study, the authors investigate the potential gains of injecting an iodinated contrast agent in combination with respiration management during CBCT acquisition for liver tumor radiotherapy. Methods: Five rabbits with implanted liver tumors were subjected to CBCT with and without motion management and contrast injection. The acquired CBCT images were registered to the planning CT to determine alignment accuracy and dosimetric impact. The authors developed a simulation tool for simulating contrast-enhanced CBCT images from dynamic contrast enhanced CT imaging (DCE-CT) to determine optimal contrast injection protocols. The tool was validated against contrast-enhanced CBCT of the rabbit subjects and was used for five human patients diagnosed with hepatocellular carcinoma. Results: In the rabbit experiment, when neither motion management nor contrast was used, tumor centroid misalignment between planning image and CBCT was 9.2 mm. This was reduced to 2.8 mm when both techniques were employed. Tumors were not visualized in clinical CBCT images of human subjects. Simulated contrast-enhanced CBCT was found to improve tumor contrast in all subjects. Different patients were found to require different contrast injections to maximize tumor contrast. Conclusions: Based on the authors’ animal study, respiration managed contrast enhanced CBCT improves IGRT significantly. Contrast enhanced CBCT benefits from patient specific tracer kinetics determined from DCE-CT.

  1. Assessment of contrast enhanced respiration managed cone-beam CT for image guided radiotherapy of intrahepatic tumors

    International Nuclear Information System (INIS)

    Purpose: Contrast enhancement and respiration management are widely used during image acquisition for radiotherapy treatment planning of liver tumors along with respiration management at the treatment unit. However, neither respiration management nor intravenous contrast is commonly used during cone-beam CT (CBCT) image acquisition for alignment prior to radiotherapy. In this study, the authors investigate the potential gains of injecting an iodinated contrast agent in combination with respiration management during CBCT acquisition for liver tumor radiotherapy. Methods: Five rabbits with implanted liver tumors were subjected to CBCT with and without motion management and contrast injection. The acquired CBCT images were registered to the planning CT to determine alignment accuracy and dosimetric impact. The authors developed a simulation tool for simulating contrast-enhanced CBCT images from dynamic contrast enhanced CT imaging (DCE-CT) to determine optimal contrast injection protocols. The tool was validated against contrast-enhanced CBCT of the rabbit subjects and was used for five human patients diagnosed with hepatocellular carcinoma. Results: In the rabbit experiment, when neither motion management nor contrast was used, tumor centroid misalignment between planning image and CBCT was 9.2 mm. This was reduced to 2.8 mm when both techniques were employed. Tumors were not visualized in clinical CBCT images of human subjects. Simulated contrast-enhanced CBCT was found to improve tumor contrast in all subjects. Different patients were found to require different contrast injections to maximize tumor contrast. Conclusions: Based on the authors’ animal study, respiration managed contrast enhanced CBCT improves IGRT significantly. Contrast enhanced CBCT benefits from patient specific tracer kinetics determined from DCE-CT

  2. Postmastectomy radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Shikama, Naoto; Koguchi, Masahiko; Sasaki, Shigeru; Kaneko, Tomoki; Shinoda, Atsunori; Nishikawa, Atsushi [Shinshu Univ., Matsumoto, Nagano (Japan). School of Medicine

    2000-10-01

    Since there have been few reports on postmastectomy radiotherapy having a high evidence level in Japan, the significance of postoperative radiotherapy and the irradiation techniques were reviewed based on reports from Western countries. Authors focused on the indications for postoperative irradiation, irradiation methods (irradiation sites, irradiation techniques; prosthetics, methods of irradiating the chest wall and lymph nodes, timing of irradiation), and complications, and discuss them. The factors thought to be adaptable to postmastectomy radiotherapy have been listed. Axillary lymph node metastasis and the size of the primary focus are thought to be important factors in locoregional recurrence. The chest wall and the supraclavicular lymph nodes are the usual sites of irradiation after mastectomy. The irradiation method consists of tangential irradiation of the chest wall and single-field irradiation of the supraclavicular lymph nodes, with 46-50 Gy in fractional doses of 1.8-2 Gy x 5/w is administered for 4.5-5.5 weeks. The timing of irradiation in the West is generally after chemotherapy. Adverse radiation effects include ischemic heart disease, pneumonitis, arm edema, rib fractures, and brachial plexus paralysis. The frequency of these complications is increased by the combined use of chemotherapy or surgery. The breast cancer cure rate in Japan is generally better than in the West. It remains to be determined whether the clinical data from Europe and America are applicable to the treatment of breast cancer in Japan. To address this issue, a clinical investigation should be performed in Japan with close cooperation between surgeons, physicians, pathologists, and radiotherapists. (K.H.)

  3. Utility of SPECT Lung Perfusion Scans in Assessing the Early Changes in Pulmonary Function after Radiotherapy for Patients with Lung Cancer

    Institute of Scientific and Technical Information of China (English)

    Wenjie Zhang; Rong Zheng; Luiun Zhao; Luhua Wang; Shengzu Chen

    2005-01-01

    OBJECTIVE Radiation-induced lung injury commonly follows radiotherapy (RT) fortumors within and near the thorax. Lung function is usually measured by pulmonary function tests (PFTs). But RT-induced regional changes of pulmonary function cannot be accurately evaluated by PFTs. Lung perfusion scintigraphy compared with other radiographic methods can assess well regional pulmonary physiological function, and a 3-dimensional conformal radiotherapy planning system can quantitatively calculate irradiation dosage. The purpose of this study is to assess, by lung perfusion scintigraphy, early changes in the pulmonary function of patients with lung cancer when receiving thoracic 3-dimensional conformal radiotherapy (3D-CRT).METHODS Nineteen patients receiving thoracic 3D-CRT for lung cancer were studied. A single photon emission computed tomography (SPECT)lung perfusion scan, X-ray or CT scan before RT and after 40~50Gy radiation were performed. Pre-RT SPECT lung perfusion images were classified by comparing lung perfusion defects with radiological abnormalities before RT. Grade 0: There was no lung perfusion defect in the area of radiological abnormality. Grade 1: The size of the radiological abnormality was similar to the area of the lung perfusion defect. Grade 2: The area of the lung perfusion defect was bigger than the size of the radiological abnormality and extended to one lobe of the lung. Grade 3: The area of lung perfusion defect exceeded one lobe of the lung. The radiation field with more than 20 Gy was drawn as a region of interest (ROI). The proportion of radioactive dose within this ROI relative to total lung dose in one slice was calculated.RESULTS All patients had lung perfusion defects, nine patients with grade 1,five patients with grade 2 and five patients with grade 3 damage,respectively. All tumors in the 19 patients were reduced in CT or X-ray images to various degrees after 40~50 Gy radiation. The mean proportion of ROI in 19 patients was 53.7±29

  4. Is it possible to improve radiotherapy team members’ communication skills? A randomized study assessing the efficacy of a 38-h communication skills training program

    International Nuclear Information System (INIS)

    Background and purpose: Optimizing communication between radiotherapy team members and patients and between colleagues requires training. This study applies a randomized controlled design to assess the efficacy of a 38-h communication skills training program. Material and methods: Four radiotherapy teams were randomly assigned either to a training program or to a waiting list. Team members’ communication skills and their self-efficacy to communicate in the context of an encounter with a simulated patient were the primary endpoints. These encounters were scheduled at the baseline and after training for the training group, and at the baseline and four months later for the waiting list group. Encounters were audiotaped and transcribed. Transcripts were analyzed with content analysis software (LaComm) and by an independent rater. Results: Eighty team members were included in the study. Compared to untrained team members, trained team members used more turns of speech with content oriented toward available resources in the team (relative rate [RR] = 1.38; p = 0.023), more assessment utterances (RR = 1.69; p < 0.001), more empathy (RR = 4.05; p = 0.037), more negotiation (RR = 2.34; p = 0.021) and more emotional words (RR = 1.32; p = 0.030), and their self-efficacy to communicate increased (p = 0.024 and p = 0.008, respectively). Conclusions: The training program was effective in improving team members’ communication skills and their self-efficacy to communicate in the context of an encounter with a simulated patient. Future study should assess the effect of this training program on communication with actual patients and their satisfaction. Moreover a cost-benefit analysis is needed, before implementing such an intensive training program on a broader scale

  5. Qualitative interpretation of PET scans using a Likert scale to assess neck node response to radiotherapy in head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sjoevall, Johanna; Wahlberg, Peter [Lund University, Department of Otorhinolaryngology (ORL)-Head and Neck Surgery, Skane University Hospital, Lund (Sweden); Bitzen, Ulrika [Lund University, Department of Clinical Physiology and Nuclear Medicine, Skane University Hospital, Lund (Sweden); Kjellen, Elisabeth; Nilsson, Per; Brun, Eva [Lund University, Department of Oncology and Radiation Physics, Skane University Hospital, Lund (Sweden)

    2016-04-15

    The aim of this study was to determine whether PET scans after radiotherapy (RT), visually interpreted as equivocal regarding metabolic neck node response can be used to accurately categorize patients as responders or nonresponders using a Likert scale and/or maximum standardized uptake value (SUVmax). Other aims were to determine the performance of different methods for assessing post-RT PET scans (visual inspection, a Likert scale and SUVmax) and to establish whether any method is superior in predicting regional control (RC) and overall survival (OS). In 105 patients with neck node-positive head and neck cancer, the neck node response was evaluated by FDG PET/CT 6 weeks after RT. The scans were clinically assessed by visual inspection and, for the purposes of this analysis, re-evaluated using the Deauville criteria, a five-point Likert scale previously used in lymphoma studies. In addition, SUVmax was determined. All assessment methods were able to significantly predict RC but not OS. The methods were also able to significantly predict remission of tumour after completion of RT. Of the 105 PET scans, 19 were judged as equivocal on visual inspection. The Likert scale was preferable to SUVmax for grouping patients as responders or nonresponders. All methods (visual inspection, SUVmax and the Likert scale) identified responders and nonresponders and predicted RC. A Likert scale is a promising tool to reduce to a minimum the problem of PET scans judged as equivocal. Consensus regarding qualitative assessment would facilitate PET reporting in clinical practice. (orig.)

  6. Lorentz expression of Maxwell's equations in a four-dimensional tensor%Maxwell方程组Lorentz表述四维张量形式的讨论

    Institute of Scientific and Technical Information of China (English)

    刘辉; 祁欣

    2012-01-01

    In this paper, we transform the Lorentz expression of Maxwell's equations to a four-dimensional tensor form by defining vector potential, scalar potential, the four-dimensional space vector and the electromagnetic field tensor. The result can better explain the movement of the electromagnetic field and verify the invariance of Maxwell's equations and the symmetry of the Lorentz expression of the four-dimensional tensor form. By listing actual examples we can verify the usefulness and effectiveness of the arithmetical method. At the same time, it can simplify the problem of a moving medium and provide some assistance in solving the movement problem, which demonstrates its superiority over the traditional form.%在经典Maxwell方程组的基础上,利用四维空间矢量和四维电磁场张量的变化规律,将Maxwell方程组Lorentz表述的场方程组变换成四维张量形式,证明了Lorentz表述四维张量形式的特点,验证了Maxwell方程组的协变性以及Lorentz表述的四维张量形式的对称性,从而更好地解释了电磁场的运动规律.通过列举实际算例验证了本文算法的实用性和有效性,简化了运动介质相关的问题,体现了在解决运动介质方面问题的优越性,为运动问题的解决提供了一定的帮助.

  7. Back Cover: Four-dimensional live imaging of hemodynamics in mammalian embryonic heart with Doppler optical coherence tomography (J. Biophotonics 8/2016).

    Science.gov (United States)

    Wang, Shang; Lakomy, David S; Garcia, Monica D; Lopez, Andrew L; Larin, Kirill V; Larina, Irina V

    2016-08-01

    Detailed volumetric measurement of hemodynamics in early developing mammalian heart can provide great insights for improved understanding of normal cardiogenesis and management of congenital cardiac disease. In this study, Doppler optical coherence tomography is performed in live mouse embryo culture to obtain the first four-dimensional high-resolution reconstruction and quantitative analysis of hemodynamic features in the mouse embryonic heart. This provides a powerful approach to investigate biomechanical regulation of early mammalian cardiogenesis. Further details can be found in the article by Shang Wang et al. on pp. 837-847. PMID:27480645

  8. The place radiotherapy alone with respect to surgery and radiotherapy in locally advanced vulva cancers

    International Nuclear Information System (INIS)

    The author report a study which aimed at evaluating the place or radiotherapy associated with surgery and of radiotherapy without surgery when taking into care locally advanced vulva cancers. The study is based on 46 cases. After 24 months, different aspects, such as recurrence and survival, have been assessed. It appears that there is no survival difference without recurrences between both sets. Short communication

  9. Proxy assessment of patients before and after radiotherapy for brain metastases. Results of a prospective study using the DEGRO brain module

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, D. [Medical School Hannover (Germany). Dept. of Radiation Oncology; Vordermark, D. [Halle-Wittenberg Univ. (Germany). Dept. of Radiation Oncology; Geinitz, H. [Technische Univ. Munich (Germany). Dept. of Radiation Oncology; Aschoff, R. [St.-Josef-Hospital, Gelsenkirchen-Horst (Germany). Dept. of Radiation Oncology; Bayerl, A. [Krems Hospital, Krems (Austria). Dept. of Radiation Oncology; Gerstein, J. [Frankfurt Univ. (Germany). Dept. of Radiation Oncology; Hipp, M.; Schaefer, C. [Regensburg Univ. (Germany). Dept. of Radiation Oncology; Oorschot, B. van [Wuerzburg Univ. (Germany). Dept. of Radiation Oncology; Wypior, H.J. [Landshut Hospital, Landshut (Germany). Dept. of Radiation Oncology

    2013-01-15

    Purpose: Proxies of patients with poor performance status could give useful information about the patients' quality of life (QoL). We applied a newly developed questionnaire in a prospective QoL study of patients undergoing radiotherapy for brain metastases in order to make the first move to validate this instrument, and we compared the results with scores obtained using validated patient-completed instruments. Materials and methods: From January 2007 to June 2010, 166 patients with previously untreated brain metastases were recruited at 14 centers in Germany and Austria. The EORTC-QLQ-C15-PAL and the brain module BN20 were used to assess QoL in patients at the start of treatment and 3 months later. At the same time points, 141 of their proxies estimated the QoL with the new DEGRO brain module (DBM), a ten-item questionnaire rating the general condition as well as functions and impairment by symptoms in areas relevant to patients with brain metastases. Results: At 3 months, 85 of 141 patients (60%) with initial response by a proxy were alive. Sixty-seven of these patients (79% of 3-month survivors) and 65 proxies completed the second set of questionnaires. After 3 months, QoL significantly deteriorated in all items of proxy-assessed QoL except headache. Correlations between self-assessed and proxy-assessed QoL were high in single items such as nausea, headache, and fatigue. Conclusions: The high correlation between self-assessment and proxy ratings as well as a similar change over time for both approaches suggest that in patients with brain metastases, proxy assessment using the DBM questionnaire can be an alternative approach to obtaining QoL data when patients are unable to complete questionnaires themselves. Our self-constructed and first applied DBM is the only highly specific instrument for patients with brain metastases, but further tests are needed for its final validation. (orig.)

  10. Nonlinear spatio-temporal filtering of dynamic PET data using a four-dimensional Gaussian filter and expectation-maximization deconvolution

    International Nuclear Information System (INIS)

    We introduce a method for denoising dynamic PET data, spatio-temporal expectation-maximization (STEM) filtering, that combines four-dimensional Gaussian filtering with EM deconvolution. The initial Gaussian filter suppresses noise at a broad range of spatial and temporal frequencies and EM deconvolution quickly restores the frequencies most important to the signal. We aim to demonstrate that STEM filtering can improve variance in both individual time frames and in parametric images without introducing significant bias. We evaluate STEM filtering with a dynamic phantom study, and with simulated and human dynamic PET studies of a tracer with reversible binding behaviour, [C-11]raclopride, and a tracer with irreversible binding behaviour, [F-18]FDOPA. STEM filtering is compared to a number of established three and four-dimensional denoising methods. STEM filtering provides substantial improvements in variance in both individual time frames and in parametric images generated with a number of kinetic analysis techniques while introducing little bias. STEM filtering does bias early frames, but this does not affect quantitative parameter estimates. STEM filtering is shown to be superior to the other simple denoising methods studied. STEM filtering is a simple and effective denoising method that could be valuable for a wide range of dynamic PET applications. (paper)

  11. Poster — Thur Eve — 66: Robustness Assessment of a Novel IMRT Planning Method for Lung Radiotherapy

    International Nuclear Information System (INIS)

    Conventional radiotherapy treatment planning for lung cancer accounts for tumour motion by increasing the beam apertures. We recently developed an IMRT planning strategy which uses reduced beam apertures in combination with an edge enhancing boost of 110% of the prescription dose to the volume that corresponds to the portion of the CTV that moves outside of the reduced beam. Previous results showed that this approach ensures target coverage while reducing lung dose. In the current study, we evaluate the robustness of this boost volume approach to changes in respiratory motion, including amplitude and phase weight variations. ITV and boost volume plans were generated for 5 NSCLC patients with respiratory motion amplitudes ranging from 1 to 2 cm. A standard 5mm PTV margin was used for all plans. The ORBIT treatment planning tool was used to plan and accumulate dose over 10 respiratory phases defined by the 4DCT datasets. For the phase weight variation study, dose was accumulated for three scenarios: equally-weighted-phases, higher weight assigned to exhale phases and higher weight assigned to inhale phases. For the amplitude variation study, a numerical phantom was used to generate 4DCT datasets corresponding to 7 mm, 10 mm and 14 mm motion amplitudes. Preliminary results found that delivered plans for all phase weight scenarios were clinically acceptable. When normalized to mean lung dose, the boost volume plan delivered 5% more dose to the CTV which indicates the potential for dose escalation using this approach

  12. Analysis of risk assessment of brachytherapy from the radiotherapy services of the metropolitan region of Rio de Janeiro, RJ, Brazil

    International Nuclear Information System (INIS)

    Currently there are few applications on the risk analysis procedures related to radiotherapy, mainly in the practice of brachytherapy. The objective of this study was to analyze the perception of risk levels, present in the practice of high dose rate brachytherapy (HDR), using a form based on the concept of the risk matrix and a database (SEVRRA) containing information about the processes related to routine brachytherapy. A form containing information regarding the brachytherapy procedure HDR and an attachment indicating how to complete it properly was delivered to a medical physicist of each service/institution. The reference value for the risk levels found, considered acceptable for all performed analyzes, was set at a percentage limit of 33% (assuming a failure in each 3 existing processes). The results showed that the overall risk analysis showed a value for average percentage of prioritized risk of 18% below the recommended range. About the analyzed groups, the higher average percentage of relative risk was found less than 12% of the recommended range, associated with the group of patients. On existing steps, the highest average percentage of relative risk was found less than 1% of the recommended range, associated with stage records and treatment planning. This study showed that although this procedure does not have a large history of accidents, still poses risks considerable that must be managed with great accuracy and immediate action to an effective decrease these risk percentages

  13. Poster — Thur Eve — 66: Robustness Assessment of a Novel IMRT Planning Method for Lung Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ahanj, M. [Department of Physics, Ryerson University, Toronto, ON (Canada); Bissonnette, J.-P. [Department of Radiation Physics, Princess Margaret Cancer Centre, Toronto, ON, Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Heath, E. [Department of Physics, Carleton University, Ottawa, ON (Canada); McCann, C. [Odette Cancer Center, Sunnybrook Health Sciences Center, Toronto, ON (Canada)

    2014-08-15

    Conventional radiotherapy treatment planning for lung cancer accounts for tumour motion by increasing the beam apertures. We recently developed an IMRT planning strategy which uses reduced beam apertures in combination with an edge enhancing boost of 110% of the prescription dose to the volume that corresponds to the portion of the CTV that moves outside of the reduced beam. Previous results showed that this approach ensures target coverage while reducing lung dose. In the current study, we evaluate the robustness of this boost volume approach to changes in respiratory motion, including amplitude and phase weight variations. ITV and boost volume plans were generated for 5 NSCLC patients with respiratory motion amplitudes ranging from 1 to 2 cm. A standard 5mm PTV margin was used for all plans. The ORBIT treatment planning tool was used to plan and accumulate dose over 10 respiratory phases defined by the 4DCT datasets. For the phase weight variation study, dose was accumulated for three scenarios: equally-weighted-phases, higher weight assigned to exhale phases and higher weight assigned to inhale phases. For the amplitude variation study, a numerical phantom was used to generate 4DCT datasets corresponding to 7 mm, 10 mm and 14 mm motion amplitudes. Preliminary results found that delivered plans for all phase weight scenarios were clinically acceptable. When normalized to mean lung dose, the boost volume plan delivered 5% more dose to the CTV which indicates the potential for dose escalation using this approach.

  14. Guide for the self-assessment of risks brought upon patients in external radiotherapy - ASN guide nr 4, Index 0, Release of the 15/01/2009

    International Nuclear Information System (INIS)

    This document contains a user's guide for radiotherapy centres which is to be read before completing the form of analysis of failure modes, their effects and criticality (AMDEC), this form which must be completed by each radiotherapy centre, and a report explaining the methodology which has been adopted to elaborate this guide

  15. Quality of life assessment in patients with Graves' disease and progressive infiltrative ophthalmopathy during combined treatment with methylprednisolone and orbital radiotherapy

    International Nuclear Information System (INIS)

    Introduction: The aim of the study was to assess quality of life (QoL) in patients with infiltrative form of Graves' ophthalmopathy (GO) during the combined pulse treatment with methylprednisolone and orbital radiotherapy, and also to search for the relation between the results of ophthalmopathy treatment and changes in QoL. Material and methods: The study involved 29 patients aged 25-74 (the mean age: 52 ±6 years) with infiltrative form of GO. They were classified for ophthalmopathy treatment on the basis of the following factors: the obtained euthyreosis, progressive character of eye changes, the level of eye changes determined on the basis of NO SPECS classification (at least class 3c), ophthalmopathy index (OI) according to Donaldson. 4. GO was diagnosed as active if CAS (clinical activity score) . 4. During the treatment, the patients received 6 cycles of methylprednisolone sodium succinate in doses of 1,0 g/24 h given as one-hour-long intravenous infusions for three successive days in a week. Between the 2nd and 4th cycle of Solu-Medrol, orbital radiotherapy with 10 MeV X-rays was performed. The control group was made up of healthy volunteers selected with regard to sex, age, educational background and nicotine addiction so as they corresponded with the study group. It involved 53 individuals aged 21-75 (the mean age: 52,4 ±14 years). QoL was assessed by means of the MOS SF-36 estionnaire. Results: Patients with GO evaluated their QoL lower than healthy individuals, which referred to physical functioning, physical and emotional role functioning, general health, vitality, social functioning, mental health and bodily pain. No correlation was found between quality of life and such factors as age, sex, or duration time of Graves disease and ophthalmopathy. Analogically, no relation was observed between the activity and stage of clinical development of eye changes and QoL. The use of the combined GO therapy contributed to a considerable decrease in the

  16. Quantification and Assessment of Interfraction Setup Errors Based on Cone Beam CT and Determination of Safety Margins for Radiotherapy.

    Directory of Open Access Journals (Sweden)

    Macarena Cubillos Mesías

    Full Text Available To quantify interfraction patient setup-errors for radiotherapy based on cone-beam computed tomography and suggest safety margins accordingly.Positioning vectors of pre-treatment cone-beam computed tomography for different treatment sites were collected (n = 9504. For each patient group the total average and standard deviation were calculated and the overall mean, systematic and random errors as well as safety margins were determined.The systematic (and random errors in the superior-inferior, left-right and anterior-posterior directions were: for prostate, 2.5(3.0, 2.6(3.9 and 2.9(3.9mm; for prostate bed, 1.7(2.0, 2.2(3.6 and 2.6(3.1mm; for cervix, 2.8(3.4, 2.3(4.6 and 3.2(3.9mm; for rectum, 1.6(3.1, 2.1(2.9 and 2.5(3.8mm; for anal, 1.7(3.7, 2.1(5.1 and 2.5(4.8mm; for head and neck, 1.9(2.3, 1.4(2.0 and 1.7(2.2mm; for brain, 1.0(1.5, 1.1(1.4 and 1.0(1.1mm; and for mediastinum, 3.3(4.6, 2.6(3.7 and 3.5(4.0mm. The CTV-to-PTV margins had the smallest value for brain (3.6, 3.7 and 3.3mm and the largest for mediastinum (11.5, 9.1 and 11.6mm. For pelvic treatments the means (and standard deviations were 7.3 (1.6, 8.5 (0.8 and 9.6 (0.8mm.Systematic and random setup-errors were smaller than 5mm. The largest errors were found for organs with higher motion probability. The suggested safety margins were comparable to published values in previous but often smaller studies.

  17. Phase I Clinical Trial Assessing Temozolomide and Tamoxifen With Concomitant Radiotherapy for Treatment of High-Grade Glioma

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Shilpen, E-mail: Shilpenp@uw.edu [Department of Radiation Oncology, University of Washington, Seattle, WA (United States); DiBiase, Steven [Robert Wood Johnson School of Medicine, Camden, NJ (United States); Meisenberg, Barry [DeCesaris Cancer Institute, Annapolis, MD (United States); Flannery, Todd [Princeton Radiation Oncology, Princeton, NJ (United States); Patel, Ashish [Division of Radiation Oncology, Abington Memorial Hospital, Abington, PA (United States); Dhople, Anil [MIMA Cancer Center, Melbourne, FL (Australia); Cheston, Sally; Amin, Pradip [Department of Radiation Oncology, University of Maryland, Baltimore, MD (United States)

    2012-02-01

    Purpose: The new standard treatment of glioblastoma multiforme is concurrent radiotherapy (RT) and temozolomide. The proliferation of high-grade gliomas might be partly dependent on protein kinase C-mediated pathways. Tamoxifen has been shown in vitro to inhibit protein kinase C through estrogen receptor-independent antineoplastic effects. This Phase I trial was designed to determine the maximal tolerated dose (MTD) of tamoxifen when given with temozolomide and concurrent RT to patients with high-grade gliomas. Methods and Materials: A total of 17 consecutive patients in four cohorts with World Health Organization Grade 3 (n = 2) and 4 (n = 15) gliomas were given tamoxifen twice daily during 6 weeks of concurrent RT and temozolomide. Eligibility included histologic diagnosis, age >18 years old, Karnofsky performance status {>=}60, and no previous brain RT or chemotherapy. The starting dose was 50 mg/m{sup 2} divided twice daily. If no dose-limiting toxicities (DLTs) occurred in 3 patients, the dose was escalated in 25-mg/m{sup 2} increments until the MTD was reached. When {>=}2 patients within a cohort experienced a DLT, the MTD had been exceeded. Temozolomide was given with RT at 75 mg/m{sup 2}. A dose of 60 Gy in 2 Gy/d fractions to a partial brain field was delivered. Results: A total of 6 patients in Cohort 4 had received tamoxifen at 125 mg/m{sup 2}. One patient was excluded, and the fourth patient developed Grade 4 thrombocytopenia (DLT). Thus, 3 more patients needed to be enrolled. A deep venous thrombosis (DLT) occurred in the sixth patient. Thus, the MTD was 100 mg/m{sup 2}. Conclusions: The MTD of tamoxifen was 100 mg/m{sup 2} when given concurrently with temozolomide 75 mg/m{sup 2} and RT. Tamoxifen might have a role in the initial treatment of high-grade gliomas and should be studied in future Phase II trials building on the newly established platform of concurrent chemoradiotherapy.

  18. Radiotherapy for Hodgkin lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Specht, Lena [Rigshospitalet Copenhagen Univ. (Denmark). Depts. of Oncology and Haematology; Yahalom, Joachim (eds.) [Memorial Sloan-Kettering Cancer, New York, NY (United States). Dept. of Radiation Oncology

    2011-07-01

    This book deals in detail with all aspects of the best practice in modern radiotherapy for Hodgkin lymphoma. It provides the background and rationale for the inclusion of radiotherapy in today's combined-modality approach, including special clinical situations such as Hodgkin lymphoma in children, in the pregnant patient, and in the elderly. Radiotherapy planning using state-of-the-art imaging, target definition, planning software, and treatment equipment is expounded in detail. Acute and long-term side effects of radiotherapy are analyzed, and the implications for modern radiotherapy approaches in Hodgkin lymphomas are explained. (orig.)

  19. Radiotherapy for Hodgkin lymphoma

    International Nuclear Information System (INIS)

    This book deals in detail with all aspects of the best practice in modern radiotherapy for Hodgkin lymphoma. It provides the background and rationale for the inclusion of radiotherapy in today's combined-modality approach, including special clinical situations such as Hodgkin lymphoma in children, in the pregnant patient, and in the elderly. Radiotherapy planning using state-of-the-art imaging, target definition, planning software, and treatment equipment is expounded in detail. Acute and long-term side effects of radiotherapy are analyzed, and the implications for modern radiotherapy approaches in Hodgkin lymphomas are explained. (orig.)

  20. Self-assessed bowel toxicity after external beam radiotherapy for prostate cancer - predictive factors on irritative symptoms, incontinence and rectal bleeding

    Directory of Open Access Journals (Sweden)

    Klotz Jens

    2009-09-01

    Full Text Available Abstract Background The aim of the study was to evaluate self-assessed bowel toxicity after radiotherapy (RT for prostate cancer. In contrast to rectal bleeding, information concerning irritative symptoms (rectal urgency, pain and incontinence after RT has not been adequately documented and reported in the past. Methods Patients (n = 286 have been surveyed prospectively before (A, at the last day (70.2-72.0 Gy; B, a median time of two (C and 16 months after RT (D using a validated questionnaire (Expanded Prostate Cancer Index Composite. Bowel domain score changes were analyzed and patient-/dose-volume-related factors tested for a predictive value on three separate factors (subscales: irritative symptoms, incontinence and rectal bleeding. Results Irritative symptoms were most strongly affected in the acute phase, but the scores of all subscales remained slightly lower at time D in comparison to baseline scores. Good correlations (correlation indices >0.4; p Conclusion PTV and specific comorbidities are important predictive factors on adverse bowel quality of life changes after RT for prostate cancer. However, greater rectum volumes inside high isodose levels have not been found to be associated with lower quality of life scores.

  1. Evaluation of novel radiotherapy technologies: what evidence is needed to assess their clinical and cost effectiveness, and how should we get it?

    Science.gov (United States)

    van Loon, Judith; Grutters, Janneke; Macbeth, Fergus

    2012-04-01

    Technical innovations in radiation oncology--eg, intensity-modulated radiotherapy, stereotactic radiotherapy, and particle therapy--can be developed rapidly and introduced into the clinic even when costs associated with their use are much higher than those for conventional radiotherapy. Although clinical benefit is expected on the basis of superior biological and physical characteristics, data for clinical effectiveness of new radiotherapy techniques are scarce. Evidence from randomised clinical trials would be ideal but such studies focus mostly on new drugs. High investment costs and modifications over time make evaluation of novel radiotherapy technologies in clinical trials more complex. Here, we propose an algorithm for evaluation of the clinical and cost effectiveness of novel radiotherapy technologies. We suggest situations when randomised trials might be feasible and the type of trial that should be undertaken when they are not. Furthermore, we discuss the usefulness of dose-distribution models for estimation of expected clinical benefit and for selection of the patients' population with the highest expected benefit. Economic modelling, including the approach of real options analysis, can inform whether implementation of a technology should begin (based on available evidence) or be delayed (until further data are available), and it can indicate the best trial design and required sample size. PMID:22469127

  2. Evaluation of novel radiotherapy technologies: what evidence is needed to assess their clinical and cost effectiveness, and how should we get it?

    Science.gov (United States)

    van Loon, Judith; Grutters, Janneke; Macbeth, Fergus

    2012-04-01

    Technical innovations in radiation oncology--eg, intensity-modulated radiotherapy, stereotactic radiotherapy, and particle therapy--can be developed rapidly and introduced into the clinic even when costs associated with their use are much higher than those for conventional radiotherapy. Although clinical benefit is expected on the basis of superior biological and physical characteristics, data for clinical effectiveness of new radiotherapy techniques are scarce. Evidence from randomised clinical trials would be ideal but such studies focus mostly on new drugs. High investment costs and modifications over time make evaluation of novel radiotherapy technologies in clinical trials more complex. Here, we propose an algorithm for evaluation of the clinical and cost effectiveness of novel radiotherapy technologies. We suggest situations when randomised trials might be feasible and the type of trial that should be undertaken when they are not. Furthermore, we discuss the usefulness of dose-distribution models for estimation of expected clinical benefit and for selection of the patients' population with the highest expected benefit. Economic modelling, including the approach of real options analysis, can inform whether implementation of a technology should begin (based on available evidence) or be delayed (until further data are available), and it can indicate the best trial design and required sample size.

  3. Prospective Preference Assessment of Patients' Willingness to Participate in a Randomized Controlled Trial of Intensity-Modulated Radiotherapy Versus Proton Therapy for Localized Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Anand [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Efstathiou, Jason A.; Paly, Jonathan J. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Halpern, Scott D. [Department of Medicine, University of Pennsylvania, Philadelphia, PA (United States); Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA (United States); Center for Bioethics, University of Pennsylvania, Philadelphia, PA (United States); Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, PA (United States); Bruner, Deborah W. [Winship Cancer Institute, Emory University, Atlanta, GA (United States); Christodouleas, John P. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Coen, John J. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Deville, Curtiland; Vapiwala, Neha [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Shipley, William U.; Zietman, Anthony L. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Hahn, Stephen M. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Bekelman, Justin E., E-mail: bekelman@uphs.upenn.edu [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, PA (United States)

    2012-05-01

    Purpose: To investigate patients' willingness to participate (WTP) in a randomized controlled trial (RCT) comparing intensity-modulated radiotherapy (IMRT) with proton beam therapy (PBT) for prostate cancer (PCa). Methods and Materials: We undertook a qualitative research study in which we prospectively enrolled patients with clinically localized PCa. We used purposive sampling to ensure a diverse sample based on age, race, travel distance, and physician. Patients participated in a semi-structured interview in which they reviewed a description of a hypothetical RCT, were asked open-ended and focused follow-up questions regarding their motivations for and concerns about enrollment, and completed a questionnaire assessing characteristics such as demographics and prior knowledge of IMRT or PBT. Patients' stated WTP was assessed using a 6-point Likert scale. Results: Forty-six eligible patients (33 white, 13 black) were enrolled from the practices of eight physicians. We identified 21 factors that impacted patients' WTP, which largely centered on five major themes: altruism/desire to compare treatments, randomization, deference to physician opinion, financial incentives, and time demands/scheduling. Most patients (27 of 46, 59%) stated they would either 'definitely' or 'probably' participate. Seventeen percent (8 of 46) stated they would 'definitely not' or 'probably not' enroll, most of whom (6 of 8) preferred PBT before their physician visit. Conclusions: A substantial proportion of patients indicated high WTP in a RCT comparing IMRT and PBT for PCa.

  4. Prognostic impact of average iodine density assessed by dual-energy spectral imaging for predicting lung tumor recurrence after stereotactic body radiotherapy.

    Science.gov (United States)

    Aoki, Masahiko; Hirose, Katsumi; Sato, Mariko; Akimoto, Hiroyoshi; Kawaguchi, Hideo; Hatayama, Yoshiomi; Fujioka, Ichitaro; Tanaka, Mitsuki; Ono, Shuichi; Takai, Yoshihiro

    2016-07-01

    The purpose of this study was to investigate the prognostic significance of average iodine density as assessed by dual-energy computed tomography (DE-CT) for lung tumors treated with stereotactic body radiotherapy (SBRT). From March 2011 to August 2014, 93 medically inoperable patients with 74 primary lung cancers and 19 lung metastases underwent DE-CT prior to SBRT of a total dose of 45-60 Gy in 5-10 fractions. Of these 93 patients, nine patients had two lung tumors. Thus, 102 lung tumors were included in this study. DE-CT was performed for pretreatment evaluation. Regions of interest were set for the entire tumor, and average iodine density was obtained using a dedicated imaging software and evaluated with regard to local control. The median follow-up period was 23.4 months (range, 1.5-54.5 months). The median value of the average iodine density was 1.86 mg/cm(3) (range, 0.40-9.27 mg/cm(3)). Two-year local control rates for the high and low average iodine density groups divided by the median value of the average iodine density were 96.9% and 75.7% (P = 0.006), respectively. Tumors with lower average iodine density showed a worse prognosis, possibly reflecting a hypoxic cell population in the tumor. The average iodine density exhibited a significant impact on local control. Our preliminary results indicate that iodine density evaluated using dual-energy spectral CT may be a useful, noninvasive and quantitative assessment of radio-resistance caused by presumably hypoxic cell populations in tumors.

  5. The Value of Down Syndrome Screening Combined with Four Dimensional Colour Doppler Ultrasound in Prenatal Diagnosis%唐氏筛查联合四维彩超在产前诊断中的价值

    Institute of Scientific and Technical Information of China (English)

    邓玲; 汤辉; 黎兴盛; 郭平

    2015-01-01

    Objective:To explore the application value of Down syndrome screening combined with four dimensional colour doppler ultrasound in prenatal diagnosis.Method:From January 2011 to December 2014, 2578 cases of pregnant women for 14 to 24 weeks were selected in maternity clinics in our hospital,they were examined by Down syndrome screening and four dimensional colour doppler ultrasound.Result:2578 cases of pregnant women were all examined by Down syndrome screening and four dimensional colour doppler ultrasound. Positive rate of Down syndrome screening was 4.84%,positive rate of was four dimensional colour doppler ultrasound was 0.96%,positive rate of combined examination was 5.81%, positive rate between Down syndrome screening and combined examination had no statistical significance (P>0.05),positive rate between four dimensional colour doppler ultrasound and combined examination had statistical significance(P0.05),与四维彩超筛查比较差异有统计学意义(P<0.05).结论:唐氏筛查联合四维彩超在产前筛查中的意义重大,可提高唐氏儿和其他染色体病儿及各种畸形的诊断率,及时做出判断是否终止妊娠,为家庭和社会减轻了沉重的负担.

  6. Diffusion-weighted magnetic resonance imaging during radiotherapy of locally advanced cervical cancer - Treatment response assessment using different segmentation methods

    DEFF Research Database (Denmark)

    Haack, Søren; Tanderup, Kari; Kallehauge, Jesper Folsted;

    2015-01-01

    distribution of ADC values. This study evaluates: 1) different segmentation methods; and 2) how they affect assessment of tumor ADC value during RT. MATERIAL AND METHODS: Eleven patients with locally advanced cervical cancer underwent MRI three times during their RT: prior to start of RT (PRERT), two weeks......2-weighted MR images using the Jaccard similarity index (JSI). ADC values from segmented volumes were compared and changes of ADC values during therapy were evaluated. RESULTS: Significant difference between the four volumes (GTV, DWIcluster, DWISD4 and DWIregion) was found (p

  7. Self-assessed bowel toxicity after external beam radiotherapy for prostate cancer - predictive factors on irritative symptoms, incontinence and rectal bleeding

    International Nuclear Information System (INIS)

    The aim of the study was to evaluate self-assessed bowel toxicity after radiotherapy (RT) for prostate cancer. In contrast to rectal bleeding, information concerning irritative symptoms (rectal urgency, pain) and incontinence after RT has not been adequately documented and reported in the past. Patients (n = 286) have been surveyed prospectively before (A), at the last day (70.2-72.0 Gy; B), a median time of two (C) and 16 months after RT (D) using a validated questionnaire (Expanded Prostate Cancer Index Composite). Bowel domain score changes were analyzed and patient-/dose-volume-related factors tested for a predictive value on three separate factors (subscales): irritative symptoms, incontinence and rectal bleeding. Irritative symptoms were most strongly affected in the acute phase, but the scores of all subscales remained slightly lower at time D in comparison to baseline scores. Good correlations (correlation indices >0.4; p < 0.001 for all) were found between irritative and incontinence function/bother scores at times B-D, suggesting the presence of an urge incontinence for the majority of patients who reported uncontrolled leakage of stool. Planning target volume (PTV), haemorrhoids and stroke in past history were found to be independent predictive factors for rectal bleeding at time D. Chronic renal failure predisposed for lower irritative scores at time D. Paradoxically, patients with greater rectum volumes inside higher isodose levels presented with higher quality of life scores in the irritative and incontinence subscales. PTV and specific comorbidities are important predictive factors on adverse bowel quality of life changes after RT for prostate cancer. However, greater rectum volumes inside high isodose levels have not been found to be associated with lower quality of life scores

  8. Radiotherapy of Cervical Cancer.

    Science.gov (United States)

    Vordermark, Dirk

    2016-01-01

    Curative-intent radical radiotherapy of cervical cancer consists of external-beam radiotherapy, brachytherapy, and concomitant chemotherapy with cisplatin. For each element, new developments aim to improve tumor control rates or treatment tolerance. Intensity-modulated radiotherapy (IMRT) has been shown to reduce gastrointestinal toxicity and can be used to selectively increase the radiotherapy dose. Individualized, image-guided brachytherapy enables better adaptation of high-dose volumes to the tumor extension. Intensification of concomitant or sequential systemic therapy is under evaluation. PMID:27614991

  9. TU-C-17A-04: BEST IN PHYSICS (THERAPY) - A Supervised Framework for Automatic Contour Assessment for Radiotherapy Planning of Head- Neck Cancer

    International Nuclear Information System (INIS)

    Purpose: Precise contour delineation of tumor targets and critical structures from CT simulations is essential for accurate radiotherapy (RT) treatment planning. However, manual and automatic delineation processes can be error prone due to limitations in imaging techniques and individual anatomic variability. Tedious and laborious manual verification is hence needed. This study develops a general framework for automatically assessing RT contours for head-neck cancer patients using geometric attribute distribution models (GADMs). Methods: Geometric attributes (centroid and volume) were computed from physician-approved RT contours of 29 head-neck patients. Considering anatomical correlation between neighboring structures, the GADM for each attribute was trained to characterize intra- and interpatient structure variations using principal component analysis. Each trained GADM was scalable and deformable, but constrained by the principal attribute variations of the training contours. A new hierarchical model adaptation algorithm was utilized to assess the RT contour correctness for a given patient. Receiver operating characteristic (ROC) curves were employed to evaluate and tune system parameters for the training models. Results: Experiments utilizing training and non-training data sets with simulated contouring errors were conducted to validate the framework performance. Promising assessment results of contour normality/abnormality for the training contour-based data were achieved with excellent accuracy (0.99), precision (0.99), recall (0.83), and F-score (0.97), while corresponding values of 0.84, 0.96, 0.83, and 0.9 were achieved for the non-training data. Furthermore, the areas under the ROC curves were above 0.9, validating the accuracy of this test. Conclusion: The proposed framework can reliably identify contour normality/abnormality based upon intra- and inter-structure constraints derived from clinically-approved contours. It also allows physicians to

  10. Main of probabilistic safety assessment (PSA) of the radiotherapy treatment process with a linear accelerator for medical purposes (linac)

    International Nuclear Information System (INIS)

    The radiation safety assessments traditionally have been based on analyzing the lessons you learn of new events that are becoming known. Although these methods are very valuable, their main limitation is that only cover known events and leave without consider other possible failures that have occurred or have not been published, This does not mean they can not occur. Other tools to analyze prospectively the safety, among which found Probabilistic Safety Assessment (PSA). This paper summarizes the project of American Forum of agencies radiological and nuclear regulators aimed at applying the methods of APS treatment process with a linear accelerator. We defined as unintended consequences accidental exposures both single patient and multiple patients. FMEA methodology was used to define events initiators of accidents and methods of event trees and trees failure to identify the accident sequences that may occur. A Once quantified the frequency of occurrence of accidental sequences Analyses of importance in determining the most recent events significant from the point of view of safety. We identified 158 of equipment failure modes and 295 errors human if they occurred would have the potential to cause the accidental exposures defined. We studied 118 of initiating events accident and 120 barriers. We studied 434 accident sequences. The accidental exposure of a single patient were 40 times likely that multiple patients. 100% of the total frequency of accidental exposures on a single patient is caused by human errors . 8% of the total frequency of accidental exposures on multiple patients initiating events may occur by equipment failure (Computerized tomography, treatment planning system, throttle linear) and 92% by human error. As part of the and recommendations of the study presents the events that are more contribution on the reduction of risk of accidental exposure. (author)

  11. Dimensional Reduction of N=1, E_8 SYM over SU(3)/U(1) x U(1) x Z_3 and its four-dimensional effective action

    CERN Document Server

    Irges, Nikos; Zoupanos, George

    2011-01-01

    We present an extension of the Standard Model inspired by the E_8 x E_8 Heterotic String. In order that a reasonable effective Lagrangian is presented we neglect everything else other than the ten-dimensional N=1 supersymmetric Yang-Mills sector associated with one of the gauge factors and certain couplings necessary for anomaly cancellation. We consider a compactified space-time M_4 x B_0 / Z_3, where B_0 is the nearly-Kaehler manifold SU(3)/U(1) x U(1) and Z_3 is a freely acting discrete group on B_0. Then we reduce dimensionally the E_8 on this manifold and we employ the Wilson flux mechanism leading in four dimensions to an SU(3)^3 gauge theory with the spectrum of a N=1 supersymmetric theory. We compute the effective four-dimensional Lagrangian and demonstrate that an extension of the Standard Model is obtained with interesting features including a conserved baryon number and fixed tree level Yukawa couplings and scalar potential. The spectrum contains new states such as right handed neutrinos and heavy ...

  12. Real-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya

    2015-09-14

    In the fields of photocatalysis and photovoltaics, ultrafast dynamical processes, including carrier trapping and recombination on material surfaces, are among the key factors that determine the overall energy conversion efficiency. A precise knowledge of these dynamical events on the nanometer (nm) and femtosecond (fs) scales was not accessible until recently. The only way to access such fundamental processes fully is to map the surface dynamics selectively in real space and time. In this study, we establish a second generation of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and demonstrate the ability to record time-resolved images (snapshots) of material surfaces with 650 fs and ∼5 nm temporal and spatial resolutions, respectively. In this method, the surface of a specimen is excited by a clocking optical pulse and imaged using a pulsed primary electron beam as a probe pulse, generating secondary electrons (SEs), which are emitted from the surface of the specimen in a manner that is sensitive to the local electron/hole density. This method provides direct and controllable information regarding surface dynamics. We clearly demonstrate how the surface morphology, grains, defects, and nanostructured features can significantly impact the overall dynamical processes on the surface of photoactive-materials. In addition, the ability to access two regimes of dynamical probing in a single experiment and the energy loss of SEs in semiconductor-nanoscale materials will also be discussed.

  13. Assimilating surface observations in a four-dimensional variational Doppler radar data assimilation system to improve the analysis and forecast of a squall line case

    Science.gov (United States)

    Chen, Xingchao; Zhao, Kun; Sun, Juanzhen; Zhou, Bowen; Lee, Wen-Chau

    2016-10-01

    This paper examines how assimilating surface observations can improve the analysis and forecast ability of a fourdimensional Variational Doppler Radar Analysis System (VDRAS). Observed surface temperature and winds are assimilated together with radar radial velocity and reflectivity into a convection-permitting model using the VDRAS four-dimensional variational (4DVAR) data assimilation system. A squall-line case observed during a field campaign is selected to investigate the performance of the technique. A single observation experiment shows that assimilating surface observations can influence the analyzed fields in both the horizontal and vertical directions. The surface-based cold pool, divergence and gust front of the squall line are all strengthened through the assimilation of the single surface observation. Three experiments—assimilating radar data only, assimilating radar data with surface data blended in a mesoscale background, and assimilating both radar and surface observations with a 4DVAR cost function—are conducted to examine the impact of the surface data assimilation. Independent surface and wind profiler observations are used for verification. The result shows that the analysis and forecast are improved when surface observations are assimilated in addition to radar observations. It is also shown that the additional surface data can help improve the analysis and forecast at low levels. Surface and low-level features of the squall line—including the surface warm inflow, cold pool, gust front, and low-level wind—are much closer to the observations after assimilating the surface data in VDRAS.

  14. Chemical and biogeophysical impact of four-dimensional (4D) seismic exploration in sub-Saharan Africa, and restoration of dysfunctionalized mangrove forests in the prospect areas.

    Science.gov (United States)

    Osuji, Leo C; Ayolagha, G; Obute, G C; Ohabuike, H C

    2007-09-01

    Four-dimensional (4D) seismic exploration, an improved geophysical technique for hydrocarbon-data acquisition, was applied for the first time in the Nembe Creek prospect area of Nigeria. The affected soils were slightly alkaline in situ when wet (pH 7.2), but extremely acidic when dry (pH 3.0). The organic carbon content (4.6-26.8%) and other physicochemical properties of soils and water (N, P, and heavy-metal contents, etc.) were higher than the baseline values obtained in 2001 before seismic profiling. Most values also exceeded the baseline compliance standards of the Department of Petroleum Resources (DPR), the World Health Organization (WHO), and the Federal Environmental Protection Agency (FEPA). Rehabilitation of the affected areas was achieved by stabilizing the mangrove floor by liming and appropriate application of nutrients, followed by replanting the cut seismic lines over a distance of 1,372 km with different mangrove species, including juvenile Rhizophora racemosa, R. mangle, and Avicennia species, which were transferred from nursery points. Quicker post-operational intervention is recommended for future 4D surveys, because the time lag between the end of seismic activity and post-impact investigation is critical in determining the relationship between activity and impact: the longer the intervening period, the more mooted the interaction. PMID:17886833

  15. The place radiotherapy alone with respect to surgery and radiotherapy in locally advanced vulva cancers; Place de la radiotherapie seule par rapport a la chirurgie et la radiotherapie dans les cancers vulvaires localement evolues

    Energy Technology Data Exchange (ETDEWEB)

    Mansouri, S.; Naim, A.; Moukhlissi, M.; Tawfik, N.; Bouchbika, Z.; Benchekroun, N.; Jouhadi, H.; Sahraoui, S.; Benider, A. [Centre de radiotherapie-oncologie, centre hospitalier universitaire, Ibn-Rochd, Casablanca (Morocco)

    2011-10-15

    The author report a study which aimed at evaluating the place or radiotherapy associated with surgery and of radiotherapy without surgery when taking into care locally advanced vulva cancers. The study is based on 46 cases. After 24 months, different aspects, such as recurrence and survival, have been assessed. It appears that there is no survival difference without recurrences between both sets. Short communication

  16. Training logbook for radiotherapy.

    NARCIS (Netherlands)

    Hunter, R.; Maciejewski, B.; Leer, J.W.H.; Kinay, M.; Heeren, G.

    2004-01-01

    AIM: To develop a structured logbook for trainees in the medical specialty of radiotherapy with Europe that records the increasing experience throughout their training period. MATERIAL AND METHODS: A working party appointed by the European Board of Radiotherapy developed a draft version of a Europea

  17. [Radiotherapy of skin cancers].

    Science.gov (United States)

    Hennequin, C; Rio, E; Mahé, M-A

    2016-09-01

    The indications of radiotherapy for skin cancers are not clearly defined because of the lack of randomised trials or prospective studies. For basal cell carcinomas, radiotherapy frequently offers a good local control, but a randomized trial showed that surgery is more efficient and less toxic. Indications of radiotherapy are contra-indications of surgery for patients older than 60, non-sclerodermiform histology and occurring in non-sensitive areas. Adjuvant radiotherapy could be proposed to squamous cell carcinomas, in case of poor prognostic factors. Dose of 60 to 70Gy are usually required, and must be modulated to the size of the lesions. Adjuvant radiotherapy seems beneficial for desmoplastic melanomas but not for the other histological types. Prophylactic nodal irradiation (45 to 50Gy), for locally advanced tumours (massive nodal involvement), decreases the locoregional failure rate but do not increase survival. Adjuvant radiotherapy (50 to 56Gy) for Merckel cell carcinomas increases also the local control rate, as demonstrated by meta-analysis and a large epidemiological study. Nodal areas must be included, if there is no surgical exploration (sentinel lymph node dissection). Kaposi sarcomas are radiosensitive and could be treated with relatively low doses (24 to 30Gy). Also, cutaneous lymphomas are good indications for radiotherapy: B lymphomas are electively treated with limited fields. The role of total skin electron therapy for T-lymphomas is still discussed; but palliative radiotherapy is very efficient in case of cutaneous nodules. PMID:27522189

  18. Targeted tumor radiotherapy

    Directory of Open Access Journals (Sweden)

    Unak Perihan

    2002-01-01

    Full Text Available Targeted tumor radiotherapy is selectively delivery of curative doses of radiation to malignant sites. The aim of the targeted tumor radiotherapy is to use the radionuclides which have high LET particle emissions conjugated to appropriate carrier molecules. The radionuclides are selectively collected by tumor cells, depositing lethal doses to tumor cells while no admission occur to normal cells. In theory, targeted radiotherapy has several advantages over conventional radiotherapy since it allows a high radiation dose to be administered without causing normal tissue toxicity, although there are some limitations in the availability of appropriate targeting agents and in the calculations of administered doses. Therefore, for routine clinical applications more progress is still needed. In this article, the potential use of targeted tumor radiotherapy is briefly reviewed. More general aspects and considerations, such as potential radionuclides, mechanisms of tumor targeting was also outlined.

  19. To understand radiotherapy

    International Nuclear Information System (INIS)

    Dealing with the use of radiotherapy for adults, this guide indicates when a radiotherapy is suggested, how it acts, how the treatment is chosen, which are the professionals involved. It describes how an external radiotherapy takes place and its various techniques, the different types of side effects (general, specific to the treated zone, late effects). It indicates which organs can be treated by curie-therapy, the different curie-therapy treatment modalities, how a curie-therapy takes place and which are its side effects. It outlines how to better cope with radiotherapy (how to be supported, the important role of relatives, everyday life questions, rights). It indicates and comments the different measures adopted for the safety and quality of radiotherapy

  20. Optimal beam arrangement for pulmonary ventilation image-guided intensity-modulated radiotherapy for lung cancer

    OpenAIRE

    Wang, Ruihao; Zhang, Shuxu; YU, HUI; Lin, Shengqu; Zhang, Guoqian; Tang, Rijie; Qi, Bin

    2014-01-01

    Background The principal aim of this study was to evaluate the feasibility of incorporating four-dimensional (4D)-computed tomography (CT)-based functional information into treatment planning and to evaluate the potential benefits of individualized beam setups to better protect lung functionality in patients with non-small cell lung cancer (NSCLC). Methods Peak-exhale and peak-inhale CT scans were carried out in 16 patients with NSCLC treated with intensity-modulated radiotherapy (IMRT). 4D-C...

  1. Mid-Ventilation Concept for Mobile Pulmonary Tumors: Internal Tumor Trajectory Versus Selective Reconstruction of Four-Dimensional Computed Tomography Frames Based on External Breathing Motion

    International Nuclear Information System (INIS)

    Purpose: To evaluate the accuracy of direct reconstruction of mid-ventilation and peak-phase four-dimensional (4D) computed tomography (CT) frames based on the external breathing signal. Methods and Materials: For 11 patients with 15 pulmonary targets, a respiration-correlated CT study (4D CT) was acquired for treatment planning. After retrospective time-based sorting of raw projection data and reconstruction of eight CT frames equally distributed over the breathing cycle, mean tumor position (Pmean), mid-ventilation frame, and breathing motion were evaluated based on the internal tumor trajectory. Analysis of the external breathing signal (pressure sensor around abdomen) with amplitude-based sorting of projections was performed for direct reconstruction of the mid-ventilation frame and frames at peak phases of the breathing cycle. Results: On the basis of the eight 4D CT frames equally spaced in time, tumor motion was largest in the craniocaudal direction, with 12 ± 7 mm on average. Tumor motion between the two frames reconstructed at peak phases was not different in the craniocaudal and anterior-posterior directions but was systematically smaller in the left-right direction by 1 mm on average. The 3-dimensional distance between Pmean and the tumor position in the mid-ventilation frame based on the internal tumor trajectory was 1.2 ± 1 mm. Reconstruction of the mid-ventilation frame at the mean amplitude position of the external breathing signal resulted in tumor positions 2.0 ± 1.1 mm distant from Pmean. Breathing-induced motion artifacts in mid-ventilation frames caused negligible changes in tumor volume and shape. Conclusions: Direct reconstruction of the mid-ventilation frame and frames at peak phases based on the external breathing signal was reliable. This makes the reconstruction of only three 4D CT frames sufficient for application of the mid-ventilation technique in clinical practice.

  2. SU-D-18A-01: Tumor Motion Tracking with a Regional Deformable Registration Model for Four Dimensional Radiation Treatment of Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chao, M; Lo, Y; Yuan, Y; Sheu, R; Rosenzweig, K [The Mount Sinai Medical Center, NY, NY (United States)

    2014-06-01

    Purpose: To develop a tumor motion model from four-dimensional computed tomography (4DCT) of thoracic patients and demonstrate its impact on 4D radiation therapy simulation. Methods: A regional deformable image registration algorithm was introduced to extract tumor motion out of patient's breathing cycle. The gross target volume (GTV) was manually delineated on a selected phase of 4DCT and a subregion with 10mm margin supplemented to the GTV was created on the Eclipse treatment planning system (Varian Medical Systems, Palo Alto, CA). Together with 4DCT the structures were exported into an inhouse research platform. A free form B-Spline deformable registration was carried out to map the subregion to other respiratory phases. The displacement vector fields were employed to propagate GTV contours with which the center of mass (CoM) of the GTV was computed for each breathing phase of 4DCT. The resultant GTV motion and its volumetric shape are utilized to facilitate 4D treatment planning. Five lung cancer patients undergoing stereotactic body radiation therapy were enrolled and their 4DCT sets were included in the study. Results: Application of the algorithm to five thoracic patients indicates that clinically satisfactory outcomes were achievable with a spatial accuracy better than 2mm for GTV contour propagation between adjacent phases, and 3mm between opposite phases. The GTV CoM was found to be in the range of 2.0mm through 2.5cm, depending upon the tumor location. Compared to the traditional whole image based registration, the computation of the regional model was found to be an order of magnitude more efficient. Conclusion: A regional deformable registration model was implemented to extract tumor motion. It will have widespread application in 4D radiation treatment planning in the future to maximally utilize the available spatial-tempo information.

  3. Comparison of primary target volumes delineated on four-dimensional CT and 18 F-FDG PET/CT of non-small-cell lung cancer

    International Nuclear Information System (INIS)

    To determine the optimal threshold of 18 F-fluorodexyglucose (18 F-FDG) positron emission tomography CT (PET/CT) images that generates the best volumetric match to internal gross target volume (IGTV) based on four-dimensional CT (4DCT) images. Twenty patients with non-small cell lung cancer (NSCLC) underwent enhanced three-dimensional CT (3DCT) scan followed by enhanced 4DCT scan of the thorax under normal free breathing with the administration of intravenous contrast agents. A total of 100 ml of ioversol was injected intravenously, 2 ml/s for 3DCT and 1 ml/s for 4DCT. Then 18 F-FDG PET/CT scan was performed based on the same positioning parameters (the same immobilization devices and identical position verified by laser localizer as well as skin marks). Gross target volumes (GTVs) of the primary tumor were contoured on the ten phases images of 4DCT to generate IGTV10. GTVPET were determined with eight different threshold using an auto-contouring function. The differences in the position, volume, concordance index (CI) and degree of inclusion (DI) of the targets between GTVPET and IGTV10 were compared. The images from seventeen patients were suitable for further analysis. Significant differences between the centric coordinate positions of GTVPET (excluding GTVPET15%) and IGTV10 were observed only in z axes (P < 0.05). GTVPET15%, GTVPET25% and GTVPET2.0 were not statistically different from IGTV10 (P < 0.05). GTVPET15% approximated closely to IGTV10 with median percentage volume changes of 4.86%. The best CI was between IGTV10 and GTVPET15% (0.57). The best DI of IGTV10 in GTVPET was IGTV10 in GTVPET15% (0.80). None of the PET-based contours had both close spatial and volumetric approximation to the 4DCT IGTV10. At present 3D-PET/CT should not be used for IGTV generation

  4. Correlations of third-trimester hiatal biometry obtained using four-dimensional translabial ultrasonography with the delivery route in nulliparous pregnant women

    Directory of Open Access Journals (Sweden)

    Teerayut Temtanakitpaisan

    2016-01-01

    Full Text Available Purpose: The goal of this study was to evaluate normal hiatal dimensions in the third trimester in nulliparous Thai pregnant women and to establish which biometric factors were associated with various pregnancy outcomes. Methods: Fifty-seven consecutive nulliparous pregnant Thai women in their third trimester were recruited on a voluntary basis from April to October 2014. All subjects underwent four-dimensional (4D translabial ultrasonography. Hiatal biometric parameters were measured at rest, while performing a Valsalva maneuver, and during contraction. Information about the patients’ eventual deliveries was obtained from their medical records. Results: The mean values of the patients’ age, body mass index, and gestational age at the time of examination were 27.4±5.47 years, 26.7±3.48 kg/m2, and 36.6±1.49 weeks, respectively. No subjects had vaginal lumps or experienced prolapse greater than stage 1 of the Pelvic Organ Prolapse Quantification system. Ultrasonography showed that the mean values of the hiatal area at rest, while performing a Valsalva maneuver, and during contraction were 13.10±2.92 cm2, 17.50±4.81 cm2, and 9.69±2.09 cm2, respectively. The hiatal area at rest, the axial measurement at rest, and the axial measurement while performing a Valsalva maneuver were significantly associated with the route of delivery (P=0.02, P=0.04, and P=0.03, respectively. Conclusion: The route of delivery was associated with hiatal biometric values measured using 4D translabial ultrasonography, based on the results of nulliparous Thai women in the third trimester.

  5. Radiotherapy for pain management of bone metastases

    International Nuclear Information System (INIS)

    Purpose: This is the first Brazilian study intended to evaluate the response of pain relief with radiotherapy in three different fractionation and the clinical differences in managing pain in patients with painful bone metastases. Methods: Prospective study of patients with painful bone metastases referred to the Radiotherapy Sector of the Hospital de Cancer de Barretos for pain-relieving radiotherapy between March and December 2010. It is known that radiotherapy seems to alter the activation of osteoclast-mediated bone resorption, relieving pain in cases of painful bone metastases. Patients were assessed in relation to the status of pain intensity before and after the initiation of radiotherapy. Either a single fraction of 8Gy, five fractions of 4Gy or ten fractions of 3Gy were given. A visual analog scale (VAS) was applied by doctors, nurses and nursing technicians to assess pain intensity at each session of radiotherapy, and follow-up at 8, 30 and 90 days from the end of treatment. Results: We evaluated 92 consecutive patients, 48 male and 44 female, with a median age of 58 years. We found that 14% of patients referred from the Palliative Care or Clinical Oncology sectors need better pharmacological analgesia due to severe pain, compared with 40.5% of patients from the other sectors (p = 0.004). We also found that the onset of pain relief to patients receiving 10 fractions of 300cGy analgesia without changing the pre-radiotherapy analgesia occurred with significance after the fifth fraction. Improvement in pain experienced within 90 days of follow-up was found in eighty percent of patients, independent of fractionated radiotherapy, site of metastases and the clinical condition of the patient. Discussion/Conclusion: The Palliative Care and Clinical Oncology sectors expressed greater concern in regards to analgesia for the patient with painful bone metastases. Radiotherapy is an effective pain-relieving treatment in different fractionation studied, even though the

  6. Radiotherapy for pain management of bone metastases

    Energy Technology Data Exchange (ETDEWEB)

    Rezende Junior, Ismar de; Mattos, Marcos Duarte de; Nakamura, Ricardo; Lemes Junior, Joaquim; Vanzelli, Talita Lozano, E-mail: rezende.med@terra.com.br [Radioterapia do Hospital de Cancer de Barretos, SP (Brazil)

    2011-07-01

    Purpose: This is the first Brazilian study intended to evaluate the response of pain relief with radiotherapy in three different fractionation and the clinical differences in managing pain in patients with painful bone metastases. Methods: Prospective study of patients with painful bone metastases referred to the Radiotherapy Sector of the Hospital de Cancer de Barretos for pain-relieving radiotherapy between March and December 2010. It is known that radiotherapy seems to alter the activation of osteoclast-mediated bone resorption, relieving pain in cases of painful bone metastases. Patients were assessed in relation to the status of pain intensity before and after the initiation of radiotherapy. Either a single fraction of 8Gy, five fractions of 4Gy or ten fractions of 3Gy were given. A visual analog scale (VAS) was applied by doctors, nurses and nursing technicians to assess pain intensity at each session of radiotherapy, and follow-up at 8, 30 and 90 days from the end of treatment. Results: We evaluated 92 consecutive patients, 48 male and 44 female, with a median age of 58 years. We found that 14% of patients referred from the Palliative Care or Clinical Oncology sectors need better pharmacological analgesia due to severe pain, compared with 40.5% of patients from the other sectors (p = 0.004). We also found that the onset of pain relief to patients receiving 10 fractions of 300cGy analgesia without changing the pre-radiotherapy analgesia occurred with significance after the fifth fraction. Improvement in pain experienced within 90 days of follow-up was found in eighty percent of patients, independent of fractionated radiotherapy, site of metastases and the clinical condition of the patient. Discussion/Conclusion: The Palliative Care and Clinical Oncology sectors expressed greater concern in regards to analgesia for the patient with painful bone metastases. Radiotherapy is an effective pain-relieving treatment in different fractionation studied, even though the

  7. Assessment of image quality and dose calculation accuracy on kV CBCT, MV CBCT, and MV CT images for urgent palliative radiotherapy treatments.

    Science.gov (United States)

    Held, Mareike; Cremers, Florian; Sneed, Penny K; Braunstein, Steve; Fogh, Shannon E; Nakamura, Jean; Barani, Igor; Perez-Andujar, Angelica; Pouliot, Jean; Morin, Olivier

    2016-01-01

    A clinical workflow was developed for urgent palliative radiotherapy treatments that integrates patient simulation, planning, quality assurance, and treatment in one 30-minute session. This has been successfully tested and implemented clinically on a linac with MV CBCT capabilities. To make this approach available to all clin-ics equipped with common imaging systems, dose calculation accuracy based on treatment sites was assessed for other imaging units. We evaluated the feasibility of palliative treatment planning using on-board imaging with respect to image quality and technical challenges. The purpose was to test multiple systems using their commercial setup, disregarding any additional in-house development. kV CT, kV CBCT, MV CBCT, and MV CT images of water and anthropomorphic phantoms were acquired on five different imaging units (Philips MX8000 CT Scanner, and Varian TrueBeam, Elekta VersaHD, Siemens Artiste, and Accuray Tomotherapy linacs). Image quality (noise, contrast, uniformity, spatial resolution) was evaluated and compared across all machines. Using individual image value to density calibrations, dose calculation accuracies for simple treatment plans were assessed for the same phantom images. Finally, image artifacts on clinical patient images were evaluated and compared among the machines. Image contrast to visualize bony anatomy was sufficient on all machines. Despite a high noise level and low contrast, MV CT images provided the most accurate treatment plans relative to kV CT-based planning. Spatial resolution was poorest for MV CBCT, but did not limit the visualization of small anatomical structures. A comparison of treatment plans showed that monitor units calculated based on a prescription point were within 5% difference relative to kV CT-based plans for all machines and all studied treatment sites (brain, neck, and pelvis). Local dose differences > 5% were found near the phantom edges. The gamma index for 3%/3 mm criteria was ≥ 95% in most

  8. Advances of Precise Radiotherapy for Lung Cancer

    OpenAIRE

    Xin WANG; Xu, Feng; Wei, Yuquan

    2011-01-01

    At present lung tumor radiation therapy has entered the accurate radiotherapy era. Precise radiotherapy includes intensity modulated radiotherapy (IMRT), image-guided radiotherapy (IGRT) and stereotactic body radiotherapy (SBRT). During the process of implementing precise radiotherapy, these problems should be fully considered to ensure executing precise radiotherapy accurately: patient positioning, controlling of the lung tumor motion, selecting of image techniques, PTV margin, dose prescrip...

  9. SU-E-J-179: Assessment of Tumor Volume Change and Movement During Stereotactic Body Radiotherapy (SBRT) for Lung Cancer: Is Adaptive Radiation Therapy (ART) Necessary?

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C; Lee, C [Asan Medical Center, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: Delineation of gross tumor volumes (GTVs) is important for stereotactic body radiotherapy (SBRT). However, tumor volume changes during treatment response. Here, we have investigated tumor volume changes and movement during SBRT for lung cancer, as a means of examining the need for adaptive radiation therapy (ART). Methods: Fifteen tumors in 15 patients with lung cancer were treated with SBRT (total dose: 60 Gy in 4 fractions). GTVs were obtained from cone-beam computed tomography scans (CBCT1–4) taken before each of the 4 fractions was administered. GTVs were delineated and measured by radiation oncologists using a treatment planning system. Variance in the tumor position was assessed between the planning CT and the CBCT images. To investigate the dosimetric effects of tumor volume changes, planning CT and CBCT4 treatment plans were compared using the conformity index (CI), homogeneity index (HI), and Paddick’s index (PCI). Results: The GTV on CBCT1 was employed as a baseline for comparisons. GTV had decreased by a mean of 20.4% (range: 0.7% to 47.2%) on CBCT4. Most patients had smaller GTVs on CBCT4 than on CBCT1. The interfractional shifts of the tumor position between the planning CT and CBCT1–4 were as follows: right-left, −0.4 to 1.3 mm; anterior-posterior, −0.8 to 0.5 mm; and superiorinferior, −0.9 to 1.1 mm. Indices for plans from the planning CT and CBCT4 were as follows: CI = 0.94±0.02 and 1.11±0.03; HI= 1.1±0.02 and 1.10±0.03; and PCI = 1.35±0.16 and 1.11±0.02, respectively. Conclusion: CI, HI, and PCI did not differ between the planning CT and CBCTs. However, daily CBCT revealed a significant decrease in the GTV during lung SBRT. Furthermore, there was an obvious interfractional shift in tumor position. Using ART could potentially lead to a reduced GTV margin and improved regional tumor control for lung cancer patients with significantly decreased GTV.

  10. SU-E-J-179: Assessment of Tumor Volume Change and Movement During Stereotactic Body Radiotherapy (SBRT) for Lung Cancer: Is Adaptive Radiation Therapy (ART) Necessary?

    International Nuclear Information System (INIS)

    Purpose: Delineation of gross tumor volumes (GTVs) is important for stereotactic body radiotherapy (SBRT). However, tumor volume changes during treatment response. Here, we have investigated tumor volume changes and movement during SBRT for lung cancer, as a means of examining the need for adaptive radiation therapy (ART). Methods: Fifteen tumors in 15 patients with lung cancer were treated with SBRT (total dose: 60 Gy in 4 fractions). GTVs were obtained from cone-beam computed tomography scans (CBCT1–4) taken before each of the 4 fractions was administered. GTVs were delineated and measured by radiation oncologists using a treatment planning system. Variance in the tumor position was assessed between the planning CT and the CBCT images. To investigate the dosimetric effects of tumor volume changes, planning CT and CBCT4 treatment plans were compared using the conformity index (CI), homogeneity index (HI), and Paddick’s index (PCI). Results: The GTV on CBCT1 was employed as a baseline for comparisons. GTV had decreased by a mean of 20.4% (range: 0.7% to 47.2%) on CBCT4. Most patients had smaller GTVs on CBCT4 than on CBCT1. The interfractional shifts of the tumor position between the planning CT and CBCT1–4 were as follows: right-left, −0.4 to 1.3 mm; anterior-posterior, −0.8 to 0.5 mm; and superiorinferior, −0.9 to 1.1 mm. Indices for plans from the planning CT and CBCT4 were as follows: CI = 0.94±0.02 and 1.11±0.03; HI= 1.1±0.02 and 1.10±0.03; and PCI = 1.35±0.16 and 1.11±0.02, respectively. Conclusion: CI, HI, and PCI did not differ between the planning CT and CBCTs. However, daily CBCT revealed a significant decrease in the GTV during lung SBRT. Furthermore, there was an obvious interfractional shift in tumor position. Using ART could potentially lead to a reduced GTV margin and improved regional tumor control for lung cancer patients with significantly decreased GTV

  11. Four and five dimensional radiotherapy with reference to prostate cancer - definitions, state of the art and further directions - an overview

    Energy Technology Data Exchange (ETDEWEB)

    Lennernaes, Bo (Dept. of Oncology, Sahlgrenska Hospital and Academy, Univ. of Gothenburg, Gothenburg (Sweden)), e-mail: bo.lennernas@telia.com; Castellanos, Enrique; Nilsson, Sten; Levitt, Seymour (Dept. of Oncology/Pathology, Karolinska Univ. Hospital and Institutet, Stockholm (Sweden))

    2011-06-15

    Radiotherapy (RT) always requires a compromise between tumor control and normal tissue side-effects. Technical innovation in radiation therapy (RT), such as three dimensional RT, is now established. Concerning prostate cancer (PC), it is reasonable to assume that RT of PC will increase in the future. The combination of small margins, a movable target (prostate), few fractions and high doses will probably demand dynamically positioning systems and in real time. This is called four dimensional radiotherapy (4DRT). Moreover, biological factors must be included in new treatments such as hypofractionation schedules. This new era is called five dimensional radiotherapy, 5DRT. In this paper we discuss new concepts in RT in respect to PC

  12. The “universal property” of horizon entropy sum of black holes in four dimensional asymptotical (anti-)de-Sitter spacetime background

    International Nuclear Information System (INIS)

    We present a new “universal property” of entropy, that is the “entropy sum” relation of black holes in four dimensional (anti-)de-Sitter asymptotical background. They depend only on the cosmological constant with the necessary effect of the un-physical “virtual” horizon included in the spacetime where only the cosmological constant, mass of black hole, rotation parameter and Maxwell field exist. When there is more extra matter field in the spacetime, one will find the “entropy sum” is also dependent of the strength of these extra matter field. For both cases, we conclude that the “entropy sum” does not depend on the conserved charges M, Q and J, while it does depend on the property of background spacetime. We will mainly test the “entropy sum” relation in static, stationary black hole and some black hole with extra matter source (scalar hair and higher curvature) in the asymptotical (anti-)de-sitter spacetime background. Besides, we point out a newly found counter example of the mass independence of the ”entropy product” relation in the spacetime with extra scalar hair case, while the “entropy sum” relation still holds. These result are indeed suggestive to some underlying microscopic mechanism. Moreover, the cosmological constant and extra matter field dependence of the “entropy sum” of all horizon seems to reveal that “entropy sum” is more general as it is only related to the background field. For the case of asymptotical flat spacetime without any matter source, we give a note for the Kerr black hole case in appendix. One will find only mass dependence of “entropy sum” appears. It makes us believe that, considering the dependence of “entropy sum”, the mass background field may be regarded as the next order of cosmological constant background field and extra matter field. However, fully explaining the relationship between the “entropy sum” relation and background properties still requires further exploration

  13. Long-term outcome and toxicity of hypofractionated stereotactic body radiotherapy as a boost treatment for head and neck cancer: the importance of boost volume assessment

    OpenAIRE

    Lee, Dong Soo; Kim, Yeon Sil; Cheon, Jae Seok; Song, Jin Ho; SON, Seok Hyun; Jang, Ji Sun; Kang, Young Nam; Kang, Jing Hyoung; Jung, So Lyoung; Yoo, Ie Ryung; Jang, Hong Seok

    2012-01-01

    Background The aim of this study was to report the long-term clinical outcomes of patients who received stereotactic body radiotherapy (SBRT) as a boost treatment for head and neck cancer. Materials and methods Between March 2004 and July 2007, 26 patients with locally advanced, medically inoperable head and neck cancer or gross residual tumors in close proximity to critical structures following head and neck surgery were treated with SBRT as a boost treatment. All patients were initially tre...

  14. Long-term outcome and toxicity of hypofractionated stereotactic body radiotherapy as a boost treatment for head and neck cancer: the importance of boost volume assessment

    OpenAIRE

    Lee Dong; Kim Yeon; Cheon Jae; Song Jin; Son Seok; Jang Ji; Kang Young; Kang Jing; Jung So; Yoo Ie; Jang Hong

    2012-01-01

    Abstract Background The aim of this study was to report the long-term clinical outcomes of patients who received stereotactic body radiotherapy (SBRT) as a boost treatment for head and neck cancer. Materials and methods Between March 2004 and July 2007, 26 patients with locally advanced, medically inoperable head and neck cancer or gross residual tumors in close proximity to critical structures following head and neck surgery were treated with SBRT as a boost treatment. All patients were init...

  15. Translation and cross-cultural adaptation into Brazilian Portuguese of the Vanderbilt Head and Neck Symptom Survey version 2.0 (VHNSS 2.0 for the assessment of oral symptoms in head and neck cancer patients submitted to radiotherapy

    Directory of Open Access Journals (Sweden)

    Eliane Marçon Barroso

    2015-12-01

    Full Text Available ABSTRACT INTRODUCTION: Patients submitted to radiotherapy for the treatment of head and neck cancer have several symptoms, predominantly oral. The Vanderbilt Head and Neck Symptom Survey version 2.0 is an American tool developed to evaluate oral symptoms in head and neck cancer patients submitted to radiotherapy. OBJECTIVE: The aim of the present study was to translate the Vanderbilt Head and Neck Symptom Survey version 2.0 into Brazilian Portuguese and cross-culturally adapt this tool for subsequent validation and application in Brazil. METHODS: A method used for the translation and cultural adaptation of tools, which included independent translations, synthesis of the translations, back-translations, expert committee, and pre-test, was used. The pre-test was performed with 37 head and neck cancer patients, who were divided into four groups, to assess the relevance and understanding of the assessed items. Data were submitted to descriptive statistical analysis. RESULTS: The overall mean of the content validity index was 0.79 for semantic and idiomatic equivalence, and it was higher than 0.8 for cultural and conceptual equivalence. The cognitive interview showed that patients were able to paraphrase the items, and considered them relevant and easily understood. CONCLUSION: The tool was translated and cross-culturally adapted to be used in Brazil. The authors believe this translation is suited for validation.

  16. Beam path toxicity in candidate organs-at-risk: Assessment of radiation emetogenesis for patients receiving head and neck intensity modulated radiotherapy

    International Nuclear Information System (INIS)

    Background: To investigate potential dose–response relationship between radiation-associated nausea and vomiting (RANV) reported during radiotherapy and candidate nausea/vomiting-associated regions of interest (CNV-ROIs) in head and neck (HNC) squamous cell carcinomas. Methods and material: A total of 130 patients treated with IMRT with squamous cell carcinomas of head and neck were evaluated. For each patient, CNV-ROIs were segmented manually on planning CT images. Clinical on-treatment RANV data were reconstructed by a review of the records for all patients. Dosimetric data parameters were recorded from dose–volume histograms. Nausea and vomiting reports were concatenated as a single binary “Any N/V” variable, and as a “CTC-V2+” variable. Results: The mean dose to CNV-ROIs was higher for patients experiencing RANV events. For patients receiving IMRT alone, a dose–response effect was observed with varying degrees of magnitude, at a statistically significant level for the area postrema, brainstem, dorsal vagal complex, medulla oblongata, solitary nucleus, oropharyngeal mucosa and whole brain CNV-ROIs. Conclusion: RANV is a common therapy-related morbidity facing patients receiving HNC radiotherapy, and, for those receiving radiotherapy-alone, is associated with modifiable dose to specific CNS structures

  17. SU-E-J-154: Image Quality Assessment of Contrast-Enhanced 4D-CT for Pancreatic Adenocarcinoma in Radiotherapy Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, W; Xue, M; Patel, K; Regine, W; Wang, J; D’Souza, W; Lu, W [University of Maryland School of Medicine, Baltimore, MD (United States); Kang, M [University of Maryland School of Medicine, Baltimore, MD (United States); Yeungnam University Medical Center, Daegu, Daegu (Korea, Republic of); Klahr, P [Philips Healthcare, Highland Heights, OH (United States)

    2015-06-15

    Purpose: This study presents quantitative and qualitative assessment of the image qualities in contrast-enhanced (CE) 3D-CT, 4D-CT and CE 4D-CT to identify feasibility for replacing the clinical standard simulation with a single CE 4D-CT for pancreatic adenocarcinoma (PDA) in radiotherapy simulation. Methods: Ten PDA patients were enrolled and underwent three CT scans: a clinical standard pair of CE 3D-CT immediately followed by a 4D-CT, and a CE 4D-CT one week later. Physicians qualitatively evaluated the general image quality and regional vessel definitions and gave a score from 1 to 5. Next, physicians delineated the contours of the tumor (T) and the normal pancreatic parenchyma (P) on the three CTs (CE 3D-CT, 50% phase for 4D-CT and CE 4D-CT), then high density areas were automatically removed by thresholding at 500 HU and morphological operations. The pancreatic tumor contrast-to-noise ratio (CNR), signal-tonoise ratio (SNR) and conspicuity (C, absolute difference of mean enhancement levels in P and T) were computed to quantitatively assess image quality. The Wilcoxon rank sum test was used to compare these quantities. Results: In qualitative evaluations, CE 3D-CT and CE 4D-CT scored equivalently (4.4±0.4 and 4.3±0.4) and both were significantly better than 4D-CT (3.1±0.6). In quantitative evaluations, the C values were higher in CE 4D-CT (28±19 HU, p=0.19 and 0.17) than the clinical standard pair of CE 3D-CT and 4D-CT (17±12 and 16±17 HU, p=0.65). In CE 3D-CT and CE 4D-CT, mean CNR (1.8±1.4 and 1.8±1.7, p=0.94) and mean SNR (5.8±2.6 and 5.5±3.2, p=0.71) both were higher than 4D-CT (CNR: 1.1±1.3, p<0.3; SNR: 3.3±2.1, p<0.1). The absolute enhancement levels for T and P were higher in CE 4D-CT (87, 82 HU) than in CE 3D-CT (60, 56) and 4DCT (53, 70). Conclusions: The individually optimized CE 4D-CT is feasible and achieved comparable image qualities to the clinical standard simulation. This study was supported in part by Philips Healthcare.

  18. SU-E-J-154: Image Quality Assessment of Contrast-Enhanced 4D-CT for Pancreatic Adenocarcinoma in Radiotherapy Simulation

    International Nuclear Information System (INIS)

    Purpose: This study presents quantitative and qualitative assessment of the image qualities in contrast-enhanced (CE) 3D-CT, 4D-CT and CE 4D-CT to identify feasibility for replacing the clinical standard simulation with a single CE 4D-CT for pancreatic adenocarcinoma (PDA) in radiotherapy simulation. Methods: Ten PDA patients were enrolled and underwent three CT scans: a clinical standard pair of CE 3D-CT immediately followed by a 4D-CT, and a CE 4D-CT one week later. Physicians qualitatively evaluated the general image quality and regional vessel definitions and gave a score from 1 to 5. Next, physicians delineated the contours of the tumor (T) and the normal pancreatic parenchyma (P) on the three CTs (CE 3D-CT, 50% phase for 4D-CT and CE 4D-CT), then high density areas were automatically removed by thresholding at 500 HU and morphological operations. The pancreatic tumor contrast-to-noise ratio (CNR), signal-tonoise ratio (SNR) and conspicuity (C, absolute difference of mean enhancement levels in P and T) were computed to quantitatively assess image quality. The Wilcoxon rank sum test was used to compare these quantities. Results: In qualitative evaluations, CE 3D-CT and CE 4D-CT scored equivalently (4.4±0.4 and 4.3±0.4) and both were significantly better than 4D-CT (3.1±0.6). In quantitative evaluations, the C values were higher in CE 4D-CT (28±19 HU, p=0.19 and 0.17) than the clinical standard pair of CE 3D-CT and 4D-CT (17±12 and 16±17 HU, p=0.65). In CE 3D-CT and CE 4D-CT, mean CNR (1.8±1.4 and 1.8±1.7, p=0.94) and mean SNR (5.8±2.6 and 5.5±3.2, p=0.71) both were higher than 4D-CT (CNR: 1.1±1.3, p<0.3; SNR: 3.3±2.1, p<0.1). The absolute enhancement levels for T and P were higher in CE 4D-CT (87, 82 HU) than in CE 3D-CT (60, 56) and 4DCT (53, 70). Conclusions: The individually optimized CE 4D-CT is feasible and achieved comparable image qualities to the clinical standard simulation. This study was supported in part by Philips Healthcare

  19. Comparison of planning target volumes based on three-dimensional CT and four-dimensional CT simulation images of non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Objective: To compare the positional and volumetric differences of planning target volumes (PTVs) based on axial three-dimensional CT (3D-CT) and four-dimensional CT (4D-CT) for the primary tumor of non-small cell lung cancer (NSCLC). Methods: Sixteen NSCLC patients with lesions located in the upper lobe and 12 patients with lesions in middle and lower lobes, totally 28 patients, initially underwent three-dimensional CT scans followed by 4D-CT scans of the thorax under normal free breathing. PTVvector was defined on gross tumor volume (GTV) contoured on 3D-CT and its motion vector. The clinical target volumes (CTVs) were created by adding 7 mm to GTVs, then, internal target volume (ITVs) were produced by enlarging CTVs isotropically based on the individually measured amount of motion in the 4D-CT, lastly, PTVs were created by adding 3 mm setup margin to ITVs. PTV4D was defined on the fusion of CTVs on all phases of the 4D data. The CTV wag generated by adding 7 mm to the GTV on each phase, then, PTVs were produced by fusing CTVs on 10 phases and adding 3 mm setup margin. The position of the target center, the volume of target and the degree of inclusion (DI) were compared reciprocally between the PTVvector and the PTV4D The difference of the position, volume and degree of inclusion of the targets between PTVvector and PTV4D were compared, and the relevance between the relative characters of the targets and the three-dimensional vector was analyzed based on the groups of the patients. Results: The median of the 3 D motion vector for the lesions in the upper lobe was 2.8 mm, significantly lower than that for the lesions in the middle and lower lobe (7.0 mm, z=-3.485, P<0.05). In the upper lobe group there was only significant spatial difference between the PTVvector and PTV4D targets in the center coordinate at the x axe (z=-2.010, P<0.05), while in the middle and lower lobes there was only significant spatial difference between the PTVvector and PTV4D targets in the

  20. Differential risk assessments from five hypoxia specific assays: The basis for biologically adapted individualized radiotherapy in advanced head and neck cancer patients

    DEFF Research Database (Denmark)

    Nordsmark, Marianne; Eriksen, Jesper Grau; Gebski, Val;

    2007-01-01

    PURPOSE: Hypoxia adversely relates with prognosis in human tumours. Five hypoxia specific predictive marker assays were compared and correlated with definitive radiotherapy. PATIENTS AND METHODS: Sixty-seven patients with advanced head and neck carcinomas were studied for pre-treatment plasma...... by competing risks HP(2.5) was the strongest variable to predict for loco-regional tumour control. CONCLUSION: There was diversity and lack of correlation among five different hypoxia assays within individual tumours. High plasma osteopontin, high HIF-1alpha and high proportion of tumour pO(2)2.5mmHg (HP(2...

  1. Clinical Progress in Four-Dimensional Ultrasound in the Prenatal Diagnosis of Fetal Echocardiogram%四维超声在胎儿心脏畸形诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    胡波; 胡兵

    2012-01-01

    复杂先天性心脏畸形的产前诊断较困难,二维超声心动图是胎儿心脏畸形产前诊断的基本检查方法.近年来,四维超声在胎儿心脏产前筛查中的应用发展迅速,通过时间空间相关成像(STIC)等动态显示模式,可实时动态显示胎儿心脏三维容积信息,更直观显示心房、心室和大动脉的解剖结构和空间关系,并能评估胎儿心脏容积等.作者拟就四维超声在胎儿心脏畸形诊断中的应用价值,综述如下.%The diagnosis of complex prenatal congenital heart diseases is difficult.Two dimensional echocardiogram is the gold standard for prenatal imaging of fetal heart.In recent years,four-dimensional echocardiogram has been developing rapidly for the diagnosis of fetal congenital heart diseases.Several developments of four-dimensional imaging techniques facilitate the application in clinical settings.The application of four-dimensional technology appears to be helpful for the understanding of cardiac anatomy,vascular development and cardiac function.Four-dimensional echocardiogram in the diagnosis of fetal congenital heart diseases opens an entirely new array of diagnostic modalities in clinical practice.

  2. Analysis of the Application of Four-Dimensional Ultrasound in the Diagnosis of Endometrial Carcinoma%四维超声在诊断子宫内膜癌中的应用分析

    Institute of Scientific and Technical Information of China (English)

    张妮妮; 薛红红

    2015-01-01

    Objective To investigate the application value of four-dimensional ultrasound in the diagnosis of endometrial carcinoma. Methods Randomly selected in our hospital from 2013 May to 2014 November 40 cases of endometrial cancer patients, and the clinical data were retrospectively analyzed, compared with two-dimensional ultrasound and four dimensional ultrasound in diagnosis of endometrial cancer. Results Four dimensional ultrasound detection rate was significantly higher than that of two-dimensional ultrasound diagnosis rate, < 0.05. Conclusion Compared with two-dimensional ultrasound, four-dimensional ultrasound can more accurately identify the endometrial cancer, can be achieved on the stereoscopic to observe the location, and to be able to accurately on the surgical staging of endometrial carcinoma, it is worthy of clinical application.%目的:探讨四维超声在诊断子宫内膜癌中的应用价值。方法随机抽取我院2013年5月~2014年11月40例子宫内膜癌患者,并对其临床资料进行回顾性分析,比较二维超声和四维超声对子宫内膜癌的诊断率,并与术后病理结果进行比较。结果四维超声检出率明显高于二维超声诊断检出率,<0.05。结论与二维超声诊断相比,四维超声检查可以更加准确的识别子宫内膜癌,能够实现对立体观察病变位置,并且能够对准确对子宫内膜癌手术进行分期,值得临床推广应用。

  3. Development of evaluation and performance verification technology for radiotherapy radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. Y.; Jang, S. Y.; Kim, B. H. and others

    2005-02-15

    No matter how much the importance is emphasized, the exact assessment of the absorbed doses administered to the patients to treat the various diseases such as lately soaring malignant tumors with the radiotherapy practices is the most important factor. In reality, several over-exposed patients from the radiotherapy practice become very serious social issues. Especially, the development of a technology to exactly assess the high doses and high energies (In general, dose administered to the patients with the radiotherapy practices are very huge doses, and they are about three times higher than the lethal doses) generated by the radiation generators and irradiation equipment is a competing issue to be promptly conducted. Over fifty medical centers in Korea operate the radiation generators and irradiation equipment for the radiotherapy practices. However, neither the legal and regulatory systems to implement a quality assurance program are sufficiently stipulated nor qualified personnel who could run a program to maintain the quality assurance and control of those generators and equipment for the radiotherapy practices in the medical facilities are sufficiently employed. To overcome the above deficiencies, a quality assurance program such as those developed in the technically advanced countries should be developed to exactly assess the doses administered to patients with the radiotherapy practices and develop the necessary procedures to maintain the continuing performance of the machine or equipment for the radiotherapy. The QA program and procedures should induce the fluent calibration of the machine or equipment with quality, and definitely establish the safety of patients in the radiotherapy practices. In this study, a methodology for the verification and evaluation of the radiotherapy doses is developed, and several accurate measurements, evaluations of the doses delivered to patients and verification of the performance of the therapy machine and equipment are

  4. Development of evaluation and performance verification technology for radiotherapy radiation

    International Nuclear Information System (INIS)

    No matter how much the importance is emphasized, the exact assessment of the absorbed doses administered to the patients to treat the various diseases such as lately soaring malignant tumors with the radiotherapy practices is the most important factor. In reality, several over-exposed patients from the radiotherapy practice become very serious social issues. Especially, the development of a technology to exactly assess the high doses and high energies (In general, dose administered to the patients with the radiotherapy practices are very huge doses, and they are about three times higher than the lethal doses) generated by the radiation generators and irradiation equipment is a competing issue to be promptly conducted. Over fifty medical centers in Korea operate the radiation generators and irradiation equipment for the radiotherapy practices. However, neither the legal and regulatory systems to implement a quality assurance program are sufficiently stipulated nor qualified personnel who could run a program to maintain the quality assurance and control of those generators and equipment for the radiotherapy practices in the medical facilities are sufficiently employed. To overcome the above deficiencies, a quality assurance program such as those developed in the technically advanced countries should be developed to exactly assess the doses administered to patients with the radiotherapy practices and develop the necessary procedures to maintain the continuing performance of the machine or equipment for the radiotherapy. The QA program and procedures should induce the fluent calibration of the machine or equipment with quality, and definitely establish the safety of patients in the radiotherapy practices. In this study, a methodology for the verification and evaluation of the radiotherapy doses is developed, and several accurate measurements, evaluations of the doses delivered to patients and verification of the performance of the therapy machine and equipment are

  5. Assessment of quality of life and changes in body composition in men with localized prostate cancer on hormone therapy combined with radiotherapy prostate cancer, quality of life, body composition

    Energy Technology Data Exchange (ETDEWEB)

    Pires, Daniele de Campos; Salvajoli, Joao Victor; Gagliardi, Joao Fernando; Evangelista, Alexandre Lopes; Lopes, Charles Ricardo; Cruz, Ticiane

    2014-07-01

    Objective: the aim of this study was to evaluate the quality of life and changes in body composition in adult men (71.3 ± 6.9 years) with prostate cancer on hormone therapy combined with radiotherapy. Methodology: to assess the quality of life of individuals, we used the 36-Item Short Form Health Survey (SF-36), which is a tool developed to survey health status in the Medical Outcomes Study. This questionnaire was applied at the beginning and six months after the start of the study. Weight was measured and the percentage of fat was estimated from an anthropometric equation from Jackson and Pollock (1978). The period of assessments and reassessments was September 2009 to October 2010. Radiotherapy was performed in other hospitals (information contained in participant's data form), as the management of patients was conducted at the oncology pharmacy of Varzea do Carmo Specialties Clinic. Results: of the eight domains of the SF-36 questionnaire, five were worse with significant differences from the first to the second assessment. They are: overall health status (p <0.01), vitality (p <0.01), functional capacity (p <0.01), social functioning (p <0.01) and pain (p <0, 01). Body weight ranged statistically significant (p <0.01) between the first evaluation (75.3 ± 12.5kg) and the second evaluation (77.4 ± 12.5kg). The same occurred with the percentage of fat, where the initial values (25.1 ± 3.8%) and final (25.8 ± 3.5%) experienced statistically significant difference (p <0.01). Conclusion: the results of this study showed that hormone therapy combined with radiotherapy led to a gain of weight and body fat percentage in the men evaluated, as well as deterioration in the quality of life of these patients. Therefore, it is necessary to continue researching this topic in order to develop strategies that mitigate the side effects of hormone therapy. The risks of hormone therapy should be evaluated and compared with gains in order to define the length of treatment

  6. [Prostate cancer external beam radiotherapy].

    Science.gov (United States)

    de Crevoisier, R; Pommier, P; Latorzeff, I; Chapet, O; Chauvet, B; Hennequin, C

    2016-09-01

    The prostate external beam radiotherapy techniques are described, when irradiating the prostate or after prostatectomy, with and without pelvic lymph nodes. The following parts are presented: indications of radiotherapy, total dose and fractionation, planning CT image acquisition, volume of interest delineation (target volumes and organs at risk) and margins, Intensity modulated radiotherapy planning and corresponding dose-volume constraints, and finally Image guided radiotherapy. PMID:27516051

  7. Radiotherapy in the management of Graves` ophthalmopathy

    Energy Technology Data Exchange (ETDEWEB)

    Sakata, Koh-ichi; Hareyama, Masato; Oouchi, Atsushi; Shidou, Mitsuo; Nagakura, Hisayasu; Morita, Kazuo; Osanai, Hajime; Ohtsuka, Kenji; Hinoda, Yuji [Sapporo Medical Univ. (Japan). School of Medicine

    1998-06-01

    To report the results of radiotherapy for patients with failure, adverse reactions or relative contraindications to the use of steroids or immunosuppressants, by using newly developed quantitative indexes. Fourteen female and six male patients with Graves` ophthalmopathy were treated with radiotherapy between 1989 and 1996. Prior to radiotherapy, eight patients received treatment with prednisone, four received immunosuppressants and four received a combination of both. Four patients with contraindications to steroids were initially managed with radiotherapy. Most of the patients received a dose of 24-28 Gy in 2 Gy fractions. We used the newly developed motility limitation index to assess extraocular motility. Treatment was well tolerated. There have been no late complications. All 12 patients with soft tissue signs such as edema, irritation, tearing and pain were improved. Proptosis did not improve or improved only slightly, 3 mm at best. However, proptosis in all but two has been stabilized and has not deteriorated in the follow-up period. Most of the patients have experienced an improvement of eye-muscle motility. Extraocular muscles that work for elevation were impaired more severely than the other muscles and this tended to remain. Of the 16 patients using steroids before or when radiotherapy was initiated, 15 were tapered off and only one patient required additional steroids, thus sparing the majority from steroid adverse reactions. Radiotherapy was effective in preventing exacerbations of active inflammatory ophthalmopathy in patients with Graves` disease with minimal morbidity and thus eliminated the adverse reactions associated with protracted corticosteroid use. The newly developed motility limitation index was useful in detecting delicate changes in motility of individual extraocular muscles. (author)

  8. Nanoparticle-guided radiotherapy

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to a method and nano-sized particles for image guided radiotherapy (IGRT) of a target tissue. More specifically, the invention relates to nano-sized particles comprising X-ray-imaging contrast agents in solid form with the ability to block x-rays, allowing for simult......The present invention relates to a method and nano-sized particles for image guided radiotherapy (IGRT) of a target tissue. More specifically, the invention relates to nano-sized particles comprising X-ray-imaging contrast agents in solid form with the ability to block x-rays, allowing...... for simultaneous or integrated external beam radiotherapy and imaging, e.g., using computed tomography (CT)....

  9. Xerostomia induced by radiotherapy

    Directory of Open Access Journals (Sweden)

    Alimi D

    2015-08-01

    Full Text Available David Alimi Department of Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh, PA, USAWe read with great interest the excellent review on xerostomia induced by radiotherapy, by Pinna et al.1 The authors should be congratulated for a very detailed review of the physiopathology, clinical symptoms, and therapeutic management of an extremely difficult condition. Although we agree that the use of anticholinergic medication represents treatment, it requires the patient to have residual salivary gland function. Unfortunately, it is well established that in most cases radiotherapy destroys most of the salivary gland and associated salivary secretions.     

  10. Advances of Precise Radiotherapy for Lung Cancer

    Directory of Open Access Journals (Sweden)

    Xin WANG

    2011-11-01

    Full Text Available At present lung tumor radiation therapy has entered the accurate radiotherapy era. Precise radiotherapy includes intensity modulated radiotherapy (IMRT, image-guided radiotherapy (IGRT and stereotactic body radiotherapy (SBRT. During the process of implementing precise radiotherapy, these problems should be fully considered to ensure executing precise radiotherapy accurately: patient positioning, controlling of the lung tumor motion, selecting of image techniques, PTV margin, dose prescription and reporting, arrangement of beams, controlling of dose volume and treatment delivering.

  11. Erythropoietin and radiotherapy; Erythropoietine et radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Le Fur, E.; Albarghach, M.N.; Pradier, O. [CHU de Morvan, Dept. de radiotherapie, 29 - Brest (France)

    2010-01-15

    Erythropoietin (E.P.O.) is a glycoprotein hormone. This hormone is a growth factor for red blood cells precursors in the bone marrow. The decrease of oxygen partial pressure, a reduced number of erythrocytes caused by bleeding or excessive destruction, or increased tissues oxygen requirements lead to increased secretion of E.P.O.. Its action takes place on bone marrow erythroblastic cells through specific receptors. E.P.O. stimulates the proliferation of red cell precursors stem cells in the bone marrow, thus increasing their production in one to two weeks. The effectiveness of E.P.O. at increasing haemoglobin and improving patients quality of life has been demonstrated by several studies. However, its use in radiotherapy remains controversial. While tumour hypoxia caused by anaemia is a factor of radio resistance and thus a source of local failure, tumour expression of E.P.O. receptors presents a significant risk for tumour progression and neo-angiogenesis, which would be increased during the administration of E.P.O.. The purpose of this article is to answer the question: is there a place for E.P.O. in combination with radiotherapy in the management of cancer?

  12. Long-term outcome and toxicity of hypofractionated stereotactic body radiotherapy as a boost treatment for head and neck cancer: the importance of boost volume assessment

    Directory of Open Access Journals (Sweden)

    Lee Dong

    2012-06-01

    Full Text Available Abstract Background The aim of this study was to report the long-term clinical outcomes of patients who received stereotactic body radiotherapy (SBRT as a boost treatment for head and neck cancer. Materials and methods Between March 2004 and July 2007, 26 patients with locally advanced, medically inoperable head and neck cancer or gross residual tumors in close proximity to critical structures following head and neck surgery were treated with SBRT as a boost treatment. All patients were initially treated with standard external beam radiotherapy (EBRT. SBRT boost was prescribed to the median 80% isodose line with a median dose of 21 (range 10–25 Gy in 2–5 (median, 5 fractions. Results The median follow-up after SBRT was 56 (range 27.6 − 80.2 months. The distribution of treatment sites in 26 patients was as follows: the nasopharynx, including the base of the skull in 10 (38.5%; nasal cavity or paranasal sinus in 8 (30.8%; periorbit in 4 (15.4%; tongue in 3 (11.5%; and oropharyngeal wall in 1 (3.8%. The median EBRT dose before SBRT was 50.4 Gy (range 39.6 − 70.2. The major response rate was 100% with 21 (80.8% complete responses (CR. Severe (grade ≥ 3 late toxicities developed in 9 (34.6% patients, and SBRT boost volume was a significant parameter predicting severe late complication. Conclusions The present study demonstrates that a modern SBRT boost is a highly efficient tool for local tumor control. However, we observed a high frequency of serious late complications. More optimized dose fractionation schedule and patient selection are required to achieve excellent local control without significant late morbidities in head and neck boost treatment.

  13. Assessment of the risk factors for impending fractures following radiotherapy for long bone metastases using CT scan-based virtual simulation: a retrospective study

    International Nuclear Information System (INIS)

    Radiotherapy for long bone metastases (RTLB) can be complicated by fractures, which considerably increase morbidity and mortality. The aim of this study was to analyze the risk factors for impending fractures following radiotherapy for long bone metastases (RTLB) using CT scan-based virtual simulation. Forty-seven (47) patients were treated with RTLB (18 lung, 11 breast, 10 prostate and 8 other cancers) for a period of 18 months. Two doctors analyzed the CT images prior to radiation therapy. The impending fractures were then monitored and the correlation between bone scan parameters and fracture occurrence was analyzed. The male gender ratio was 0.57 and the mean age 62.8 (33–93) years. The average size of the metastatic lesions was 32 (8–87) x 2 (6–81) x 52 (7–408) mm with cortical involvement (CI) in 66% of cases. The site was in the upper third of the bone in 92% of cases (28 femoral, 17 humeral and two tibial). Ten fractures occurred: two during RTLB, seven after one month and one after 6.6 months. The fractured lesions measured 48 (17–87) x 34 (12–66) x 76 (38–408) mm. The predictive parameters for fracture were osteolytic (39% vs. 10%; p = 0.02) and permeative lesions (42% vs. 0%; p < 0.0005), a Mirels score ≥9 (42% vs. 0%; p < 0.0005), circumferential CI ≥30% (71% vs. 0%, p < 0.00001), CI ≥45 mm in height (67% vs. 0%, p < 0.00001) and CI in thickness =100% (40% vs. 0%; p = 0.0008). In the multivariate analysis, circumferential CI ≥30% was the only predictive parameter for fracture (p = 0.00035; OR = 62; CI 95%: 6.5-595). Overall survival was 91% and 40% at one month and twelve months respectively. Prophylactic primary fixation surgery should always be considered when the circumferential CI ≥30%

  14. Bowel disease after radiotherapy

    International Nuclear Information System (INIS)

    The clinical presentation, operative findings and outcome in 40 patients who required surgery for bowel disease after radiotherapy are presented. The type of presentation varied according to the time after radiotherapy. In the first month, many patients had a proctitis but none required surgery. Five patients were operated on within one month, 2 for radiation-induced acute ileitis and 3 for exacerbations of pre-existing disease (diverticular disease 2, ulcerative colitis 1). The commonest time of presentation was between 3 and 18 months after radiotherapy, when 20 patients needed surgery for bowel disease caused by radiation-induced local ischaemia. Twelve of these patients had chronic perforation, 6 had severe rectal bleeding and 2 had painful anorectal ulceration. Fifteen patients presented between 2 and 24 years after radiotherapy, usually with incomplete intestinal obstruction due to a fibrous stricture, but 2 patients had rectal carcinoma. Wide resection of the involved bowel was the principal method of treatment but any anastomosis was protected by a proximal defunctioning stoma. There was no operative mortality but 10 patients have died subsequently. The danger of dismissing these patients as having incurable malignancy is stressed because, although the condition is infrequent, it is usually amenable to adequate surgery. (author)

  15. Adjuvant radiotherapy for gallbladder cancer: A dosimetric comparison of conformal radiotherapy and intensity-modulated radiotherapy

    Institute of Scientific and Technical Information of China (English)

    Xiao-Nan Sun; Qi Wang; Ben-Xing Gu; Yan-Hong Zhu; Jian-Bin Hu; Guo-Zhi Shi; Shu Zheng

    2011-01-01

    AIM: To assess the efficacy and toxicity of conformal radiotherapy (CRT) and compare with intensity-modulated radiotherapy (IMRT) in the treatment of gallbladder cancer.METHODS: Between November 2003 and January 2010, 20 patients with gallbladder cancer were treated with CRT with or without chemotherapy after surgical resection. Preliminary survival data were collected and examined using both Kaplan-Meier and actuarial analysis. Demographic and treatment parameters were collected. All patients were planned to receive 46-56 Gy in 1.8 or 2.0 Gy per fraction. CRT planning was compared with IMRT.RESULTS: The most common reported acute toxicities requiring medication (Radiation Therapy Oncology Group, Radiation Therapy Oncology Group Grade2) were nausea (10/20 patients) and diarrhea (3/20).There were no treatment-related deaths. Compared with CRT planning, IMRT significantly reduced the volume of right kidney receiving > 20 Gy and the volume of liver receiving > 30 Gy. IMRT has a negligible impact on the volume of left kidney receiving > 20 Gy. The 95% of prescribed dose for a planning tumor volume using either 3D CRT or IMRT planning were 84.0% ±6.7%, 82.9% ± 6.1%, respectively (P > 0.05).CONCLUSION: IMRT achieves similar excellent target coverage as compared with CRT planning, while reducingthe mean liver dose and volume above threshold dose. IMRT offers better sparing of the right kidney compared with CRT planning, with a significantly lower mean dose and volume above threshold dose.

  16. Symptomatic vertebral hemangioma: Treatment with radiotherapy

    Directory of Open Access Journals (Sweden)

    Aich Ranen

    2010-01-01

    Full Text Available Background: Vertebrae are the second commonest site among skeletal locations affected by hemangioma, but only about one per cent becomes symptomatic throughout the life. Though surgery, intra vertebral injection of various sclerosing agents have been tried in treating this benign process, no general consensus regarding management has been reached. Radiotherapy is emerging as a low cost, simple, non-invasive but very effective modality of treatment of symptomatic vertebral hemangioma. Aim: This study aims to find out the role of external beam radiotherapy in alleviating the symptoms of symptomatic vertebral hemangiomas without compromising the quality of life. Materials and Methods: Seven consecutive patients with symptomatic vertebral hemangioma were treated with a fixed dose of external beam radiotherapy; and muscle power was assessed before, after treatment and during follow-up. Results: All patients showed improvement of muscle power, which increased with the passage of time. Pain relief with improvement of quality of life was obtained in all the patients. Conclusion: Effect of radiotherapy on vertebral hemangioma is dose-dependent and the dose limiting factor is the spinal cord tolerance. In the present era of IMRT, greater dose can be delivered to the parts of vertebra affected by the hemangioma without compromising the spinal cord tolerance and expected to give better results.

  17. The IAEA Quality Audits for Radiotherapy

    International Nuclear Information System (INIS)

    The IAEA/WHO thermoluminescent dosimetry (TLD) postal dose audit programme has been used for over 8000 radiotherapy beams throughout the world in over four decades of its operation. Records have been kept of the results of TLD audits since the inception of the programme. Analysis of these data has yielded much interesting information. In the early years, the TLD service recorded approximately 50% audited beams having adequate calibration. This percentage of acceptable results has now increased to 96%. Obviously, regular participation in dosimetry audit stimulates an improvement in dosimetry practices in radiation therapy in many hospitals worldwide. Another dosimetry audit programme for treatment planning (TPS audit) in external beam radiotherapy, which has been developed by the IAEA, assesses the radiotherapy workflow for conformal techniques, from patient data acquisition and computerized treatment planning to dose delivery. The IAEA supports national and subregional TPS audit activities to improve the quality and safety of dose calculation in radiotherapy. The third audit modality operated by the IAEA within the framework of the Quality Assurance Team for Radiation Oncology (QUATRO) is a comprehensive audit that reviews radiation oncology practices with the aim to improve quality. To date, over 50 QUATRO audits have been organized by the IAEA in radiation oncology centres in Europe, Africa, Asia and Latin America. QUATRO audits indicate and document areas for improvement and provide advice for further development of the audited centres. (author)

  18. Quality assurance in radiotherapy

    International Nuclear Information System (INIS)

    Good radiotherapy results and safety of treatment require the radiation to be optimally applied to a specified target area and the correct dose. According to international recommendations, the average uncertainty in therapeutic dose should not exceed 5%. The need for high precision in therapeutic dose requires quality assurance covering the entire radiotherapy process. Besides the physical and technical characteristics of the therapy equipment, quality assurance must include all radiotherapy equipment and procedures that are significant for the correct magnitude and precision of application of the therapeutic dose. The duties and responsibilities pertaining to various stages of treatment must also be precisely defined. These requirements may be best implemented through a quality system. The general requirements for supervision and quality assurance of medical radiation apparatus are prescribed in section 40 of the Radiation Act (592/1991, amendment 1142/1998) and in sections 18 and 32 of the Decree of the Ministry of Social Affairs and Health on the medical use of radiation (423/2000). Guide ST 2.2 imposes requirements on structural radiation shielding of radiotherapy equipment and the premises in which it is used, and on warning and safety arrangements. Guide ST 1.1 sets out the general safety principles for radiation practices and regulatory control procedure for the use of radiation. Guide ST 1.6 provides general requirements for operational measures in the use of radiation. This Guide sets out the duties of responsible parties (the party running a radiation practice) in respect of arranging and maintaining radiotherapy quality assurance. The principles set out in this Guide and Guide ST 6.3 may be applied to radionuclide therapy

  19. [Radiotherapy of breast cancer].

    Science.gov (United States)

    Hennequin, C; Barillot, I; Azria, D; Belkacémi, Y; Bollet, M; Chauvet, B; Cowen, D; Cutuli, B; Fourquet, A; Hannoun-Lévi, J M; Leblanc, M; Mahé, M A

    2016-09-01

    In breast cancer, radiotherapy is an essential component of the treatment. After conservative surgery for an infiltrating carcinoma, radiotherapy must be systematically performed, regardless of the characteristics of the disease, because it decreases the rate of local recurrence and by this way, specific mortality. Partial breast irradiation could not be proposed routinely but only in very selected and informed patients. For ductal carcinoma in situ, adjuvant radiotherapy must be also systematically performed after lumpectomy. After mastectomy, chest wall irradiation is required for pT3-T4 tumours and if there is an axillary nodal involvement, whatever the number of involved lymph nodes. After neo-adjuvant chemotherapy and mastectomy, in case of pN0 disease, chest wall irradiation is recommended if there is a clinically or radiologically T3-T4 or node positive disease before chemotherapy. Axillary irradiation is recommended only if there is no axillary surgical dissection and a positive sentinel lymph node. Supra and infra-clavicular irradiation is advised in case of positive axillary nodes. Internal mammary irradiation must be discussed case by case, according to the benefit/risk ratio (cardiac toxicity). Dose to the chest wall or the breast must be between 45-50Gy with a conventional fractionation. A boost dose over the tumour bed is required if the patient is younger than 60 years old. Hypofractionation (42.5 Gy in 16 fractions, or 41.6 Gy en 13 or 40 Gy en 15) is possible after tumorectomy and if a nodal irradiation is not mandatory. Delineation of the breast, the chest wall and the nodal areas are based on clinical and radiological evaluations. 3D-conformal irradiation is the recommended technique, intensity-modulated radiotherapy must be proposed only in case of specific clinical situations. Respiratory gating could be useful to decrease the cardiac dose. Concomitant administration of chemotherapy in unadvised, but hormonal treatment could be start with

  20. Radiotherapy Breast Boost With Reduced Whole-Breast Dose Is Associated With Improved Cosmesis: The Results of a Comprehensive Assessment From the St. George and Wollongong Randomized Breast Boost Trial

    International Nuclear Information System (INIS)

    Purpose: To evaluate comprehensively the effect of a radiotherapy boost on breast cosmetic outcomes after 5 years in patients treated with breast-conserving surgery. Methods: The St. George and Wollongong trial (NCT00138814) randomized 688 patients with histologically proven Tis-2, N 0–1, M0 carcinoma to the control arm of 50 Gy in 25 fractions (342 patients) and the boost arm of 45 Gy in 25 fractions to the whole breast followed by a 16 Gy in 8 fraction electron boost (346 patients). Five-year cosmetic outcomes were assessed by a panel subjectively in 385 patients and objectively using pBRA (relative breast retraction assessment). A subset of patients also had absolute BRA measurements. Clinician assessment and patient self-assessment of overall cosmetic and specific items as well as computer BCCT.core analysis were also performed. Results: The boost arm had improved cosmetic overall outcomes as scored by the panel and BCCT.core software with 79% (p = 0.016) and 81% (p = 0.004) excellent/good cosmesis respectively compared with 68% in no-boost arm. The boost arm also had lower pBRA and BRA values with a mean difference of 0.60 and 1.82 mm, respectively, but was not statistically significant. There was a very high proportion of overall excellent/good cosmetic outcome in 95% and 93% in the boost and no–boost arms using patient self-assessment. However, no difference in overall and specific items scored by clinician assessment and patient self-assessment was found. Conclusion: The results show the negative cosmetic effect of a 16-Gy boost is offset by a lower whole-breast dose of 45 Gy.

  1. Radiotherapy Breast Boost With Reduced Whole-Breast Dose Is Associated With Improved Cosmesis: The Results of a Comprehensive Assessment From the St. George and Wollongong Randomized Breast Boost Trial

    Energy Technology Data Exchange (ETDEWEB)

    Hau, Eric, E-mail: helloerico@yahoo.com [Cancer Care Centre, St. George Hospital, Kogarah, Sydney (Australia); Browne, Lois H.; Khanna, Sam; Cail, Stacy; Cert, Grad; Chin, Yaw; Clark, Catherine; Inder, Stephanie; Szwajcer, Alison; Graham, Peter H. [Cancer Care Centre, St. George Hospital, Kogarah, Sydney (Australia)

    2012-02-01

    Purpose: To evaluate comprehensively the effect of a radiotherapy boost on breast cosmetic outcomes after 5 years in patients treated with breast-conserving surgery. Methods: The St. George and Wollongong trial (NCT00138814) randomized 688 patients with histologically proven Tis-2, N 0-1, M0 carcinoma to the control arm of 50 Gy in 25 fractions (342 patients) and the boost arm of 45 Gy in 25 fractions to the whole breast followed by a 16 Gy in 8 fraction electron boost (346 patients). Five-year cosmetic outcomes were assessed by a panel subjectively in 385 patients and objectively using pBRA (relative breast retraction assessment). A subset of patients also had absolute BRA measurements. Clinician assessment and patient self-assessment of overall cosmetic and specific items as well as computer BCCT.core analysis were also performed. Results: The boost arm had improved cosmetic overall outcomes as scored by the panel and BCCT.core software with 79% (p = 0.016) and 81% (p = 0.004) excellent/good cosmesis respectively compared with 68% in no-boost arm. The boost arm also had lower pBRA and BRA values with a mean difference of 0.60 and 1.82 mm, respectively, but was not statistically significant. There was a very high proportion of overall excellent/good cosmetic outcome in 95% and 93% in the boost and no-boost arms using patient self-assessment. However, no difference in overall and specific items scored by clinician assessment and patient self-assessment was found. Conclusion: The results show the negative cosmetic effect of a 16-Gy boost is offset by a lower whole-breast dose of 45 Gy.

  2. Long-term results of radiotherapy for pituitary adenomas. Evaluation of tumor control and hypopituitarism after radiotherapy

    International Nuclear Information System (INIS)

    To evaluate the results of conventional radiotherapy for pituitary adenomas assessed with computed tomography (CT) or magnetic resonance imaging (MRI). Endpoints include tumor control, normalization of hormone levels in functioning adenomas, and hypopituitarism after radiotherapy as an adverse effect. Forty-two patients were treated with radiotherapy from 1982 to 1995 at Niigata University Hospital. Forty patients were irradiated after surgery because of residual adenomas in 33 patients and tumor regrowth in 7 patients. One patient was treated with radiotherapy alone, and the remaining 1 patient was treated with preoperative radiotherapy. Tumor size and extension were evaluated using CT or MRI, and all tumors were macroadenomas. They consisted of 18 non-functioning and 24 functioning adenomas (growth hormone (GH)-secreting: 11, prolactinomas: 7, concomitant GH and prolactin (PRL)-secreting: 5, gonadotropin-secreting: 1). Treatment was given in 200 cGy daily fraction size and a total dose of 50 Gy was given to most patients. Sixteen patients with GH- and/or PRL-secreting adenomas received bromocriptine. Tumor progression was determined by increase in tumor size as shown by CT or MRI. Hypopituitarism after radiotherapy was evaluated using the functions of corticotropin (ACTH), thyrotropin (TSH), and gonadotropin. Median follow-up time from the end of radiotherapy was 103 months. Tumor progression occurred in 2 out of 42 patients and 10-year progression-free rate for all patients was 93.7%. Normalization of GH levels was obtained in 12 of 16 GH-secreting adenomas with a mean time of 27 months after radiotherapy, and 9 of 12 PRL-secreting adenomas achieved normalization of PRL levels with a mean time of 34 months. One gonadotropin-secreting adenoma achieved normalization of gonadotropin level at 21 months after radiotherapy. The incidence of hypopituitarism after radiotherapy increased with time, and cumulative risk of deficiencies of ACTH, TSH, and gonadotropin at 10

  3. Long-term results of radiotherapy for pituitary adenomas. Evaluation of tumor control and hypopituitarism after radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchida, Emiko; Sakai, Kunio; Matsumoto, Yasuo; Sugita, Tadashi; Sasamoto, Ryuta [Niigata Univ. (Japan). School of Medicine

    1999-09-01

    To evaluate the results of conventional radiotherapy for pituitary adenomas assessed with computed tomography (CT) or magnetic resonance imaging (MRI). Endpoints include tumor control, normalization of hormone levels in functioning adenomas, and hypopituitarism after radiotherapy as an adverse effect. Forty-two patients were treated with radiotherapy from 1982 to 1995 at Niigata University Hospital. Forty patients were irradiated after surgery because of residual adenomas in 33 patients and tumor regrowth in 7 patients. One patient was treated with radiotherapy alone, and the remaining 1 patient was treated with preoperative radiotherapy. Tumor size and extension were evaluated using CT or MRI, and all tumors were macroadenomas. They consisted of 18 non-functioning and 24 functioning adenomas (growth hormone (GH)-secreting: 11, prolactinomas: 7, concomitant GH and prolactin (PRL)-secreting: 5, gonadotropin-secreting: 1). Treatment was given in 200 cGy daily fraction size and a total dose of 50 Gy was given to most patients. Sixteen patients with GH- and/or PRL-secreting adenomas received bromocriptine. Tumor progression was determined by increase in tumor size as shown by CT or MRI. Hypopituitarism after radiotherapy was evaluated using the functions of corticotropin (ACTH), thyrotropin (TSH), and gonadotropin. Median follow-up time from the end of radiotherapy was 103 months. Tumor progression occurred in 2 out of 42 patients and 10-year progression-free rate for all patients was 93.7%. Normalization of GH levels was obtained in 12 of 16 GH-secreting adenomas with a mean time of 27 months after radiotherapy, and 9 of 12 PRL-secreting adenomas achieved normalization of PRL levels with a mean time of 34 months. One gonadotropin-secreting adenoma achieved normalization of gonadotropin level at 21 months after radiotherapy. The incidence of hypopituitarism after radiotherapy increased with time, and cumulative risk of deficiencies of ACTH, TSH, and gonadotropin at 10

  4. The Value of Four-dimensional Ultrasound Combined with Two-dimensional Ultrasound in Diagnosis of Fetal Malformations%二维联合四维超声在胎儿畸形诊断中的价值

    Institute of Scientific and Technical Information of China (English)

    孙巧霞; 王云; 孙京倩; 随璐

    2014-01-01

    Objective:To investigate the value of two-dimensional ultrasound combined with four-dimensional ultrasound in the diagnosis of fetal malformation.Method:A total of 11 573 pregnant women did the examination in Qinghe County Central Hospital from April 2011 to March 2013,and the two-dimensional ultrasound were used to do the prenatal screening,and the suspect deformity children were detected by the two-dimensional ultrasound and four-dimensional ultrasound,and these result and results of the induction and follow-up were compared.Result:The total relevance ratios of the two methods were compared,and the difference was statistically significant(P<0.05).Conclusion:It should use two-dimensional ultrasound to screening firstly in the diagnosis of fetal malformations,and then it should use two-dimensional ultrasound combined with four-dimensional ultrasound as supplement.The four-dimensional ultrasound has great advances in the diagnosis of deformities in the face,extremities,spine and other surface,can improve the diagnose accordance rate of fetal malformation,has a high practical clinical value.%目的:探讨利用二维超声联合四维超声诊断胎儿畸形的临床价值。方法:选择2011年4月-2013年3月来清河县中心医院进行检查的11573例孕妇,利用二维超声对其进行产前筛查,对于疑似畸形患儿进行二维和四维超声联合检查,所得结果与引产和随访结果进行比较。结果:两种方法总检出率比较,差异有统计学意义(P<0.05)。结论:诊断胎儿畸形应首先利用二维超声进行筛查,再联合四维超声进行补充诊断。四维超声在诊断颜面部、四肢、脊柱等体表畸形方面具有明显的优势,可提高胎儿畸形的诊断符合率,具有较高的临床实用价值。

  5. Dynamic MRI Analysis of Tumor and Organ Motion During Rest and Deglutition and Margin Assessment for Radiotherapy of Head-and-Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, Julie A.; Paulson, Eric S.; Ahunbay, Ergun; Schultz, Christopher; Li, X. Allen [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States); Wang Dian, E-mail: dwang@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States)

    2011-12-01

    Purpose: To quantify swallowing frequency and tumor and normal structure displacements during deglutition using dynamic magnetic resonance imaging (MRI) and to determine planning target volume (PTV) margins to account for resting and deglutition-induced displacements in patients with head-and-neck cancer (HNC). Methods and Materials: Twenty-two patients with HNC were imaged in the treatment position using dynamic MRI. Sagittal images were acquired. Two-dimensional displacement was analyzed using contours of normal structures and GTV drawn for one swallowing event. Deglutition-induced displacements were quantified based on position change during deglutition relative to preswallow structure location for anterior (A), posterior (P), superior (S), and inferior (I) directions. Additional long-time MRI series were obtained from a subset of 11 patients while they were resting in order to determine swallowing frequency and duration. PTV margins to account for setup error, frequency and duration of deglutition, and resting and deglutition-induced GTV motion were calculated. Results: Mean maximum resting displacements ranged from 1.5 to 3.1 mm for combined GTV subsites. Mean maximum swallowing GTV displacement for combined subsites ranged from 4.0 to 11.6 mm. Swallowing was nonperiodic, with a frequency ranging from 0 to 19 swallows over 12.8 min and mean swallow duration of 3.5 s. Based on the average swallowing characteristics in this cohort, the average PTV margins to account for setup error and tumor motion are estimated to be 4.7 mm anteriorly, 4.2 mm posteriorly, 4.7 mm inferiorly, and 6.0 mm superiorly. Conclusions: The measurable mean maximum resting displacement for the GTV indicates that tumor motion occurs even when the patient is not swallowing. Nonuniform margins should be used as a standard PTV margin that accounts for setup error and tumor motion in radiotherapy of HNC unless adaptive radiotherapy with respect to intrafraction tumor motion is performed. The

  6. A review of stereotactic body radiotherapy – is volumetric modulated arc therapy the answer?

    OpenAIRE

    Sapkaroski, Daniel; Osborne, Catherine; Knight, Kellie A

    2015-01-01

    Stereotactic body radiotherapy (SBRT) is a high precision radiotherapy technique used for the treatment of small to moderate extra-cranial tumours. Early studies utilising SBRT have shown favourable outcomes. However, major disadvantages of static field SBRT include long treatment times and toxicity complications. Volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) may potentially mitigate these disadvantages. This review aims to assess the feasibility of emerg...

  7. Radiotherapy of bronco-pulmonary cancer; Radiotherapie des cancers brochopulmonaires

    Energy Technology Data Exchange (ETDEWEB)

    Bourry, N.; Millardet, C.; Lapeyre, M.; Verrelle, P.; Gross, E.; Champeaux-Orange, E.; Lahbabi, K.; Galland, S.; Chomy, F.; Lagarde, P.; Blanchard, P

    2007-11-15

    Six oral communications as follow: tomography by positron emission with {sup 18}F-FDG and target volume determination in the non at small cells bronchi cancers: interest and limit; adjuvant radiotherapy in the non at small cells pulmonary cancers; pulmonary stereotaxic radiotherapy; the chemoradiotherapy of locally evolved bronco-pulmonary cancers; the mesothelioma: place of radiotherapy; predictive factors of the toxicity and the care of complications of thorax irradiation. (N.C.)

  8. Radiotherapy of cutaneous lymphomas; Radiotherapie des lymphomes cutanes

    Energy Technology Data Exchange (ETDEWEB)

    Kirova, Y.M.; Piedbois, Y.; Pan, Q.; Guo, J.P.; Le Bourgeois, J.P. [Hopital Henri-Mondor, 94 - Creteil (France). Dept. de cancerologie

    1999-03-01

    Radiotherapy plays an important role in the treatment of cutaneous lymphomas. In the treatment of Mycosis fungoides, total skin electron beam radiation therapy is efficient for patients with limited and superficial forms of the disease. Radiotherapy is also efficient for the locally advanced forms of non-epidermo-tropic lymphomas. The palliative radiotherapy is indicated for advanced, nodular and treatment resistant forms of cutaneous lymphomas and for voluminous lymphadenopathies. (authors)

  9. External audit in radiotherapy dosimetry

    International Nuclear Information System (INIS)

    Quality audit forms an essential part of any comprehensive quality assurance programme. This is true in radiotherapy generally and in specific areas such as radiotherapy dosimetry. Quality audit can independently test the effectiveness of the quality system and in so doing can identify problem areas and minimize their possible consequences. Some general points concerning quality audit applied to radiotherapy are followed by specific discussion of its practical role in radiotherapy dosimetry, following its evolution from dosimetric intercomparison exercises to routine measurement-based on-going audit in the various developing audit networks both in the UK and internationally. Specific examples of methods and results are given from some of these, including the Scottish+ audit group. Quality audit in radiotherapy dosimetry is now well proven and participation by individual centres is strongly recommended. Similar audit approaches are to be encouraged in other areas of the radiotherapy process. (author)

  10. Radiotherapy for aggressive fibromatosis

    International Nuclear Information System (INIS)

    Purpose/Objective: To evaluate local control with radiotherapy for aggressive fibromatosis. Materials and Methods: Fifty-three patients with histologically confirmed aggressive fibromatosis were treated with radiotherapy at the University of Florida between March 1975 and June 1992. The minimum length of follow-up was 2 years; 88% of patients had follow-up for at least 5 years. Thirty-nine patients had lesions in an extremity and 14 patients had lesions in the trunk. Twenty-nine patients were treated for gross disease. Patients were treated with total doses between 35 Gy and 70 Gy; 83% of patients received 50 Gy to 60 Gy. Results: Local control was achieved in 23 of 29 patients (79%) treated for postoperative microscopic residual disease. Local control was achieved in 21 of 24 patients (88%) treated for gross disease; gross disease was controlled in 8 of 8 patients with previously untreated lesions, and in 13 of 16 patients treated for postoperative gross residual and recurrent disease. Overall, aggressive fibromatosis was locally controlled in 83% of treated patients. All 9 treatment failures occurred with extremity lesions 4 to 68 months after initiation of treatment. Of the 9 recurrences, 4 were out-of-field, 3 were in-field, and 4 occurred at the margin of the irradiated field. Salvage was successful in 8 of 9 patients in whom salvage was attempted with surgery alone or combined with postoperative radiotherapy. A functional limb was maintained in 38 of 39 patients with extremity or limb girdle lesions. The most serious complication of treatment was pathologic fracture, which occurred in 3 of 53 treated patients; all 3 fractures healed with conservative management. Conclusion: Radiotherapy is a valuable adjunct to surgery in the management of aggressive fibromatosis and can be used alone in patients with unresectable or inoperable disease

  11. Xerostomia induced by radiotherapy

    OpenAIRE

    Alimi, David

    2015-01-01

    David Alimi Department of Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh, PA, USAWe read with great interest the excellent review on xerostomia induced by radiotherapy, by Pinna et al.1 The authors should be congratulated for a very detailed review of the physiopathology, clinical symptoms, and therapeutic management of an extremely difficult condition. Although we agree that the use of anticholinergic medication represents treatment, it requires the patient to have resi...

  12. Probing into Chemical Sales Customer Service Innovation Based on Four-Dimensional Model%基于四维模型的化工销售客户服务创新探讨

    Institute of Scientific and Technical Information of China (English)

    牟慈

    2015-01-01

    服务创新是当今制造企业转型发展的新趋势,是企业获得核心竞争力的新源泉。本文通过阐述服务创新四维模型理论,尝试分析化工销售客户服务现状及存在问题,提出化工销售客户服务创新借鉴四维模型的相关建议。%Service innovation is not only the new trend of manufacturing enterprise transformational development but also the new source for enterprises to acquire core competitiveness. Through expounding on four-dimensional model theory for service innovation, the article tries out an analysis of chemical sales customer service status as well as existing problems and puts forward relevant suggestions for drawing lessons from four-dimensional model in chemical sales customer service innovation.

  13. Bladder filling variations during concurrent chemotherapy and pelvic radiotherapy in rectal cancer patients: early experience of bladder volume assessment using ultrasound scanner

    International Nuclear Information System (INIS)

    To describe the early experience of analyzing variations and time trends in bladder volume of the rectal cancer patients who received bladder ultrasound scan. We identified 20 consecutive rectal cancer patients who received whole pelvic radiotherapy (RT) and bladder ultrasound scan between February and April 2012. Before simulation and during the entire course of treatment, patients were scanned with portable automated ultrasonic bladder scanner, 5 times consecutively, and the median value was reported. Then a radiation oncologist contoured the bladder inner wall shown on simulation computed tomography (CT) and calculated its volume. Before simulation, the median bladder volume measured using simulation CT and bladder ultrasound scan was 427 mL (range, 74 to 1,172 mL) and 417 mL (range, 147 to 1,245 mL), respectively. There was strong linear correlation (R = 0.93, p < 0.001) between the two results. During the course of treatment, there were wide variations in the bladder volume and every time, measurements were below the baseline with statistical significance (12/16). At 6 weeks after RT, the median volume was reduced by 59.3% to 175 mL. Compared to the baseline, bladder volume was reduced by 38% or 161 mL on average every week for 6 weeks. To our knowledge, this study is the first to prove that there are bladder volume variations and a reduction in bladder volume in rectal cancer patients. Moreover, our results will serve as the basis for implementation of bladder training to patients receiving RT with full bladder.

  14. The utility of FDG-PET for assessing outcomes in oligometastatic cancer patients treated with stereotactic body radiotherapy: a cohort study

    International Nuclear Information System (INIS)

    Studies suggest that patients with metastases limited in number and destination organ benefit from metastasis-directed therapy. Stereotactic body radiotherapy (SBRT) is commonly used for metastasis directed therapy in this group. However, the characterization of PET response following SBRT is unknown in this population. We analyzed our cohort of patients to describe the PET response following SBRT. Patients enrolled on a prospective dose escalation trial of SBRT to all known sites of metastatic disease were reviewed to select patients with pre- and post-therapy PET scans. Response to SBRT was characterized on PET imaging based on standard PET response criteria and compared to CT based RECIST criteria for each treated lesion. 31 patients had PET and CT data available before and after treatment for analysis in this study. In total, 58 lesions were treated (19 lung, 11 osseous, 11 nodal, 9 liver, 6 adrenal and 2 soft tissue metastases). Median follow-up was 14 months (range: 3–41). Median time to first post-therapy PET was 1.2 months (range; 0.5-4.1). On initial post-therapy PET evaluation, 96% (56/58) of treated metastases responded to therapy. 60% (35/58) had a complete response (CR) on PET and 36% (21/58) had a partial response (PR). Of 22 patients with stable disease (SD) on initial CT scan, 13 had CR on PET, 8 had PR, and one had SD. Of 21 metastases with PET PR, 38% became CR, 52% remained PR, and 10% had progressive disease on follow-up PET. 10/35 lesions (29%) with an initial PET CR progressed on follow-up PET scan with median time to progression of 4.11 months (range: 2.75-9.56). Higher radiation dose correlated with long-term PET response. PET response to SBRT enables characterization of metastatic response in tumors non-measurable by CT. Increasing radiation dose is associated with prolonged complete response on PET

  15. Unstimulated Salivary Flow Rate Corresponds with Severity of Xerostomia: Evaluation using Xerostomia Questionnaire and Groningen Radiotherapy- Induced Xerostomia Questionnaire

    OpenAIRE

    Friendika Dhiah Ayu Intan Shinta; Nushita Dinar; Hendri Susanto; Dewi Agustina

    2014-01-01

    One of the oral complications in head and neck radiotherapy is xerostomia. The severity of xerostomia can be observed using objective examination (unstimulated salivary flow rate measurement) and subjective examination (assessment using xerostomia questionnaires). There are two questionnaires used in assessment of xerostomia in head and neck cancer radiotherapy namely Xerostomia Questionnaire (XQ) and Groningen Radiotherapy-Induced Xerostomia Questionnaire (GRIX). Objective: To know the corre...

  16. Sexual morbidity following radiotherapy for germ cell of the testis

    Energy Technology Data Exchange (ETDEWEB)

    Tinkler, S.D.; Howard, G.C.W.; Kerr, G.R. (Western General Hospital, Edinburgh (United Kingdom))

    1992-11-01

    An anonymous questionnaire study was designed to assess sexual function after orchidectomy and radiotherapy for testicular cancer. Questionnaires were sent to: (1) 237 patients treated with orchidectomy and abdominal radio-therapy in Edinburgh from 1974 to 1988; (2) 32 patients under 'surveillance' following orchidectomy alone; (3) 402 'normal' age-matched controls. All were asked questions concerning sexual function over the preceding 6 months. All the patients were also asked the same questions with reference to the first 6 months after completion of treatment. Completed questionnaires were returned from 137 (62%) radiotherapy patients, 18 (56%) surveillance patients and 121 (35%) controls. There was a significant difference between the radiotherapy patients and the controls in almost all the parameters looked at including erection, ejaculation and libido with the treated group performing less well. In addition, almost 24% of radiotherapy patients felt disabled or disfigured by the treatment, most commonly because of the presence of only one testicle. A deterioration in sexual function was observed with increasing age. In the radiotherapy group there was no difference in response between the 2 time periods or in any of the treatment variables. The clinical significance of these observations are unclear but together with increasing information on other toxicities emerging following this therapy the role of radiation for early stage seminoma is being brought into question. This study also confirms the morbidity of orchidectomy. It is suggested that testicular implants should be offered more widely. (author). 28 refs., 6 figs.

  17. An instrument dedicated for modelling of pulmonary radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: Radiotherapy plays a pivotal role in lung cancer treatment. Selection of patients for new (radio)therapeutic options aiming at improving outcomes requires reliable and validated prediction models. We present the implementation of a prospective platform for evaluation and development of lung radiotherapy (proPED-LUNG) as an instrument enabling multidimensional predictive modelling. Materials and methods: ProPED-LUNG was designed to comprise relevant baseline and follow up data of patients receiving pulmonary radiotherapy with curative intent. Patient characteristics, diagnostic and staging information, treatment parameters including full dose–volume-histograms, tumour control, survival, and toxicity are scored. Besides physician-rated data, a range of patient-rated data regarding symptoms and health-related quality-of-life are collected. Results: After 18 months of accrual, 315 patients have been included (accrual rate, 18 per month). Of the first hundred patients included, 70 received conformal (chemo)radiotherapy and 30 underwent stereotactic radiotherapy. Compliance at 3 and 6 months follow-up was 96–100% for patient-rated, and 81–94% for physician-rated assessments. For data collection, 0.4 FTE were allocated in a 183 FTE department (0.2%). Conclusions: ProPED-LUNG is feasible with high compliance rates and yields a large amount of high quality prospective disease-related, treatment-related, patient- and physician-rated data which can be used to evaluate new developments in pulmonary radiotherapy

  18. Factors associated with refusal of radiotherapy among oral cancer patients

    Directory of Open Access Journals (Sweden)

    Agaku IT

    2013-04-01

    Full Text Available Background: Surgery is commonly favored in the management of oral cancer but radiotherapy may be essential because of the size or location of the tumor. Refusal of radiotherapy by patients is an important issue, which must be taken into consideration during treatment planning. This study assessed prevalence and correlates of radiotherapy refusal among oral cancer patients. Methods: Data was analyzed for 47, 174 oral cancer cases in the Surveillance, Epidemiology and End Results (SEER database during 1988–2008. Point estimates were calculated overall and by selected socio-demographic and clinical characteristics. A multivariate logistic regression model was fitted to determine predictors of radiotherapy refusal. Results: The overall prevalence of refusal of radiotherapy was 2.31%. Factors associated with increased likelihood of refusal of radiotherapy included age ± 45 years (adjusted odds ratio, aOR=2.48; P=0.031; gingival/floor of mouth tumors (aOR=1.32; P=0.010; receipt of surgery (aOR=1.21; P=0.04. Conversely, protective factors included being married (aOR=0.59; P<0.001; non-Hispanic blacks (aOR=0.53; P=0.001; involvement of paired structures (aOR=0.61; P<0.001 as well as multiple tumors (aOR=0.75; P=0.021. Sex was not a significant predictor on multivariate analysis. Conclusion: Prevalence of refusal of radiotherapy among oral cancer patients is relatively low and is significantly associated with age, marital status, as well as location, extent and severity of disease. Clinicians may anticipate patients likely to refuse radiotherapy and develop patient-tailored counseling considering the benefits and risks of proposed treatment. Final treatment decision must however take into consideration the wishes of the fully informed patient.

  19. Radiotherapy of presenile spinal osteoporosis

    International Nuclear Information System (INIS)

    Painfull conditions of presenile spinal osteoporosis may no longer respond to medication or physical therapy. Analgesic radiotherapy coupled with mild physical therapy and if necessary supported by orthopedic measures frequently results in pain relief and physical stability. Fifty-two cases of osteoporosis and osteoporotic spinal fractures illustrate how better longterm results are achieved by increasing the customary dosage and speeding up radiotherapy. (orig.)

  20. Plan optimization for stereotactic radiotherapy

    NARCIS (Netherlands)

    J.A. de Pooter (Jacobus Abraham)

    2008-01-01

    textabstractCancer is one of the leading causes of death in the world. Next to surgery and chemotherapy, radiotherapy is one of the most used treatment modalities for cancer. About 50% of the patients with cancer will be treated with radiotherapy during the management of their disease. In radiothera

  1. CMTO Four-dimensional Analysis Method of Competitive Intelligence and Its Application%竞争情报分析的CMTO四维分析法及其应用

    Institute of Scientific and Technical Information of China (English)

    苗红; 宋昱晓; 黄鲁成; 娄岩; 王晓宇

    2015-01-01

    Competitive intelligence analysis method is the key way to acquire the most accurate competitive intelligence It is also the basis of competitive intelligence application to be realized. This paper proposes a"Capability-Market-Time-Opportunity" four-dimensional a-nalysis method ( hereinafter referred to as CMTO four-dimensional analysis method) , which offsets the deficiency of the CMT three-di-mensional analysis for lack of direction caused by negligence of competitive opportunities analysis . And this method augments the amount of information in competitive intelligence analysis. This paper carries out empirical study on the application of CMTO four-dimensional a-nalysis method by taking wearable technology. For example,this method verifies the feasibility and superiority of CMTO. Research results show that the following fields are more competitive in the future:carrier and material, measurement, battery and circuit, etc. CMTO can help enterprises by providing fairly comprehensive, valuable intelligence information.%竞争情报分析方法是获取竞争情报最精准、最有价值的关键途径,也是竞争情报应用得以实现的基础。提出一种“市场-能力-时间-机会”四维分析方法(简称CMTO四维分析法),弥补了CMT三维分析法未考虑分析竞争机会而缺乏方向性的不足,增加了竞争情报分析的信息量。并用可穿戴技术验证了该方法的可行性及优越性。研究表明未来竞争机会较大的技术领域集中在载体和材料、测量、电池和电路装置等,为辅助企业决策提供了较为全面而有价值的情报信息。

  2. Radiotherapy for eyelid cancer

    Energy Technology Data Exchange (ETDEWEB)

    Saika, Kazumi [Yokohama City Univ. (Japan). School of Medicine

    2001-05-01

    Some studies on radiotherapy for eyelid cancer have been reported, but the optimal radiation doses for different histological types and tumor sizes have not been detailed. So I studied the optimal radiation doses in radiotherapy for eyelid cancer. The patients were fourteen and histological diagnoses were made on the basis of biopsies or surgery before radiotherapy. Surgical cut margins were positive in 10 cases. In 5 of these cases, tumors were visible. There were 9 sebaceous adenocarcinomas (SAC), 4 squamous cell carcinomas (SCC), and 1 basal cell carcinoma (BCC). In 13 of 14 cases, radiation was applied to eyelids in which tumor-surgical cut margin distances were 3 mm or less. The eyeballs were covered with lead or tungsten shields, and the eyelids were irradiated with a total dose of 50 to 66.6 Gy. In 5 cases, radiation was applied prophylactically for ipsilateral pre-auricle lymph node areas. 11 of 13 cases were locally controlled. I gave greater radiation doses for SAC than for SCC or BCC. I also gave greater doses for in visible tumors than for invisible ones. In the acute phase dermatitis, inflammation of the cornea, conjunctivitis, etc. occurred but they were mild. Later reactions were decreased cilia, dry eye, inflammation of cornea, conjunctivitis, discomfort of the scar, etc. Cataracts were also seen, but they were of senile origen. Because 81.8% of the tumors were controlled, this radiation method was useful with salvage therapies to select an optimal radiation dose according to the differences among histological types and tumor sizes. 60% of visible tumors were also controlled so I think that radical therapy using radiation alone is possible. (author)

  3. Respiratory gated radiotherapy-pretreatment patient specific quality assurance.

    Science.gov (United States)

    Thiyagarajan, Rajesh; Sinha, Sujit Nath; Ravichandran, Ramamoorthy; Samuvel, Kothandaraman; Yadav, Girigesh; Sigamani, Ashok Kumar; Subramani, Vikraman; Raj, N Arunai Nambi

    2016-01-01

    Organ motions during inter-fraction and intra-fraction radiotherapy introduce errors in dose delivery, irradiating excess of normal tissue, and missing target volume. Lung and heart involuntary motions cause above inaccuracies and gated dose delivery try to overcome above effects. Present work attempts a novel method to verify dynamic dose delivery using a four-dimensional (4D) phantom. Three patients with mobile target are coached to maintain regular and reproducible breathing pattern. Appropriate intensity projection image set generated from 4D-computed tomography (4D-CT) is used for target delineation. Intensity modulated radiotherapy plans were generated on selected phase using CT simulator (Siemens AG, Germany) in conjunction with "Real-time position management" (Varian, USA) to acquire 4D-CT images. Verification plans were generated for both ion chamber and Gafchromic (EBT) film image sets. Gated verification plans were delivered on the phantom moving with patient respiratory pattern. We developed a MATLAB-based software to generate maximum intensity projection, minimum intensity projections, and average intensity projections, also a program to convert patient breathing pattern to phantom compatible format. Dynamic thorax quality assurance (QA) phantom (Computerized Imaging Reference Systems type) is used to perform the patient specific QA, which holds an ion chamber and film to measure delivered radiation intensity. Exposed EBT films are analyzed and compared with treatment planning system calculated dose. The ion chamber measured dose shows good agreement with planned dose within ± 0.5% (0.203 ± 0.57%). Gamma value evaluated from EBT film shows passing rates 92-99% (96.63 ± 3.84%) for 3% dose and 3 mm distance criteria. Respiratory gated treatment delivery accuracy is found to be within clinically acceptable level. PMID:27051173

  4. Respiratory gated radiotherapy-pretreatment patient specific quality assurance

    Directory of Open Access Journals (Sweden)

    Rajesh Thiyagarajan

    2016-01-01

    Full Text Available Organ motions during inter-fraction and intra-fraction radiotherapy introduce errors in dose delivery, irradiating excess of normal tissue, and missing target volume. Lung and heart involuntary motions cause above inaccuracies and gated dose delivery try to overcome above effects. Present work attempts a novel method to verify dynamic dose delivery using a four-dimensional (4D phantom. Three patients with mobile target are coached to maintain regular and reproducible breathing pattern. Appropriate intensity projection image set generated from 4D-computed tomography (4D-CT is used for target delineation. Intensity modulated radiotherapy plans were generated on selected phase using CT simulator (Siemens AG, Germany in conjunction with "Real-time position management" (Varian, USA to acquire 4D-CT images. Verification plans were generated for both ion chamber and Gafchromic (EBT film image sets. Gated verification plans were delivered on the phantom moving with patient respiratory pattern. We developed a MATLAB-based software to generate maximum intensity projection, minimum intensity projections, and average intensity projections, also a program to convert patient breathing pattern to phantom compatible format. Dynamic thorax quality assurance (QA phantom (Computerized Imaging Reference Systems type is used to perform the patient specific QA, which holds an ion chamber and film to measure delivered radiation intensity. Exposed EBT films are analyzed and compared with treatment planning system calculated dose. The ion chamber measured dose shows good agreement with planned dose within ± 0.5% (0.203 ± 0.57%. Gamma value evaluated from EBT film shows passing rates 92–99% (96.63 ± 3.84% for 3% dose and 3 mm distance criteria. Respiratory gated treatment delivery accuracy is found to be within clinically acceptable level.

  5. 四维彩超在胎儿先天性畸形中的临床诊断价值%Four-dimensional color Doppler ultrasound in examination in prenatal screening of fetal malformation

    Institute of Scientific and Technical Information of China (English)

    罗妙云

    2014-01-01

    目的 探讨四维彩超在胎儿先天性畸形中的诊断价值.方法 随机观察我院2012年1月至2014年1月孕中晚期孕妇1200例产前常规超声检查结果,所有孕妇均进行了二维超声和四维超声检查,并随访至产后1个月,比较二维超声和四维超声诊断胎儿先天性畸形的准确性.结果 经产后临床证实,共发现先天性胎儿畸形34例,其中神经管畸形10例,心脏畸形8例,唇腭裂7例,泌尿系畸形3例,四肢畸形3例,腹部畸形1例,其他2例.四维超声检出畸形31例,与产后符合率91.17%;漏诊3例,其中多指畸形1例,脊柱裂2例.二维超声检出畸形26例,符合率76.47%;漏诊8例,其中唇腭裂2例,多指畸形2例,脊柱裂3例,足内翻1例.二维和四维超声的诊断符合率比较差异具有统计学意义(P<0.05).结论 四维超声更能多方位、多切面观察胎儿宫内发育情况,对诊断胎儿体表畸形具有更直观和准确的判断,具有较高的临床价值.%Objective To investigate the diagnostic value of four-dimensional (4D) color Doppler ultrasound examination in prenatal screening of fetal malformation.Methods 1200 pregnant women were observed and detected by four-dimensional color Doppler and two dimensional ultrasound.The results were compared with the results confirmed by clinical pathology.Results 34 cases were detected with congenital defects; among which,10 got defects in nervous system,8 heart deformity,7 cheilopalatognathus,3 urinary tract malformation,3 limb deformity,1 abdominal deformity,and the other 2 cases.31 cases were detected with deformity by four-dimensional color Doppler,with a postpartum coincidence rate of 91.17%; and 3 cases were misdiagnosed,of which 1 case had polydactyly deformity and 2 cases spina bifida.26 cases were detected with deformity by two-dimensional ultrasony,with a postpartum coincidence rate of 76.47%; and 8 cases were misdiagnosed,of which 2 cases had cleft lip and palate,2 case polydactyly

  6. Breast cancer radiotherapy: controversies and prospectives

    Institute of Scientific and Technical Information of China (English)

    YU Jin-ming; WANG Yong-sheng

    2008-01-01

    @@ Despite consensus on breast cancer radiotherapy, there are still some controversies over post-mastectomy radiotherapy (PMRT) in patients with 1-3 positive lymph nodes, accelerated partial breast irradiation (APBI), appropriate sequence of radiotherapy, chemotherapy and hormonal treatment, and radiotherapy after preoperative systemic therapy.

  7. Fertility impairment in radiotherapy.

    Science.gov (United States)

    Biedka, Marta; Kuźba-Kryszak, Tamara; Nowikiewicz, Tomasz; Żyromska, Agnieszka

    2016-01-01

    Infertility as a result of antineoplastic therapy is becoming a very important issue due to the growing incidence of neoplastic diseases. Routinely applied antineoplastic treatments and the illness itself lead to fertility disorders. Therapeutic methods used in antineoplastic treatment may cause fertility impairment or sterilization due to permanent damage to reproductive cells. The risk of sterilization depends on the patient's sex, age during therapy, type of neoplasm, radiation dose and treatment area. It is known that chemotherapy and radiotherapy can lead to fertility impairment and the combination of these two gives an additive effect. The aim of this article is to raise the issue of infertility in these patients. It is of growing importance due to the increase in the number of children and young adults who underwent radiotherapy in the past. The progress in antineoplastic therapy improves treatment results, but at the same time requires a deeper look at existential needs of the patient. Reproductive function is an integral element of self-esteem and should be taken into account during therapy planning. PMID:27647982

  8. Advances in radiotherapy

    International Nuclear Information System (INIS)

    Radiation therapy is in the midst of a rebirth largely driven by the use of computers for treatment planning and beam delivery. The first edge of this renaissance was the advent of three-dimensional conformal radiation therapy (3-D CRT). This was enabled by the widespread availability and utilization of three-dimensional imaging such as computed tomography and magnetic resonance scanning, themselves products of the computer revolution. For the first time this allowed radiation oncologists to segment and visualize the tumor in association with it neighboring sensitive soft-tissue structures. Software tools to visualize the beam paths through the body enabled the beam directions and beam shapes to be manually optimized. Simultaneously, improved dose calculations utilizing the CT images of the patient anatomy produced more accurate distributions of dose. The dose was delivered with custom-shaped blocks or recently collimators with multiple leaves that allow complex shaped fields to be delivered without the need for block fabrication. In the last couple of decades new treatment delivery methodologies have emerged. The first has been stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) which is the purview of neurosurgeons (who call it SRS) as well as radiation oncologists (who usually call it SRT). SRS and SRT are premised on multiple beams focusing on one location typically with circular aperture collimators but increasingly with fields shaped by multi-leaved collimators. Often only a single treatment session (the usual for SRS) is used when the treatment volume is small, but for larger lesions several treatment sessions, or fractions, are used (most often for SRT) to allow for normal tissue repair. The new equipment market for SRS and SRT is about 10% of the total for radiation therapy. Intensity-modulated radiation therapy (IMRT) is the latest treatment methodology and its adoption has been extremely rapid, particularly in the United States. IMRT uses

  9. Evaluation of urologic morbidity after radiotherapy for cervical carcinoma by urodynamic examinations and patient voiding schemes: a prospective study

    DEFF Research Database (Denmark)

    Lajer, Henrik; Thranov, Ingrid R; Bagi, Per;

    2002-01-01

    To assess urologic morbidity in a 5-year period by urodynamic examinations and patient voiding schemes after radiotherapy and brachytherapy for cervical carcinoma.......To assess urologic morbidity in a 5-year period by urodynamic examinations and patient voiding schemes after radiotherapy and brachytherapy for cervical carcinoma....

  10. Translational Research to Improve the Efficacy of Carbon Ion Radiotherapy: Experience of Gunma University.

    Science.gov (United States)

    Oike, Takahiro; Sato, Hiro; Noda, Shin-Ei; Nakano, Takashi

    2016-01-01

    Carbon ion radiotherapy holds great promise for cancer therapy. Clinical data show that carbon ion radiotherapy is an effective treatment for tumors that are resistant to X-ray radiotherapy. Since 1994 in Japan, the National Institute of Radiological Sciences has been heading the development of carbon ion radiotherapy using the Heavy Ion Medical Accelerator in Chiba. The Gunma University Heavy Ion Medical Center (GHMC) was established in the year 2006 as a proof-of-principle institute for carbon ion radiotherapy with a view to facilitating the worldwide spread of compact accelerator systems. Along with the management of more than 1900 cancer patients to date, GHMC engages in translational research to improve the treatment efficacy of carbon ion radiotherapy. Research aimed at guiding patient selection is of utmost importance for making the most of carbon ion radiotherapy, which is an extremely limited medical resource. Intratumoral oxygen levels, radiation-induced cellular apoptosis, the capacity to repair DNA double-strand breaks, and the mutational status of tumor protein p53 and epidermal growth factor receptor genes are all associated with X-ray sensitivity. Assays for these factors are useful in the identification of X-ray-resistant tumors for which carbon ion radiotherapy would be beneficial. Research aimed at optimizing treatments based on carbon ion radiotherapy is also important. This includes assessment of dose fractionation, normal tissue toxicity, tumor cell motility, and bystander effects. Furthermore, the efficacy of carbon ion radiotherapy will likely be enhanced by research into combined treatment with other modalities such as chemotherapy. Several clinically available chemotherapeutic drugs (carboplatin, paclitaxel, and etoposide) and drugs at the developmental stage (Wee-1 and heat shock protein 90 inhibitors) show a sensitizing effect on tumor cells treated with carbon ions. Additionally, the efficacy of carbon ion radiotherapy can be improved by

  11. Chest wall desmoid tumours treated with definitive radiotherapy: a plan comparison of 3D conformal radiotherapy, intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy

    OpenAIRE

    Liu, Jia; Ng, Diana; Lee, James; Stalley, Paul; Hong, Angela

    2016-01-01

    Purpose Definitive radiotherapy is often used for chest wall desmoid tumours due to size or anatomical location. The delivery of radiotherapy is challenging due to the large size and constraints of normal surrounding structures. We compared the dosimetry of 3D conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc radiotherapy (VMAT) to evaluate the best treatment option. Methods and materials Ten consecutive patients with inoperable chest wall de...

  12. Respiratory gating and four-dimensional tomotherapy

    Science.gov (United States)

    Zhang, Tiezhi

    Helical tomotherapy is a new IMRT delivery process developed at the University of Wisconsin and TomoTherapy Inc. Tomotherapy may be of advantage in lung cancer treatment due to its rational delivery mode. As with conventional IMRT delivery, however, intrafraction respiratory motion during a tomotherapy treatment causes unnecessary radiation to the healthy tissue. Possible solutions to these problems associated with intrafraction motion have been studied in this thesis. A spirometer is useful for monitoring breathing because of its direct correlation with lung volume changes. However, its inherent drift prevents its application in long term breathing monitoring. With a calibration and stabilization algorithm, a spirometer is able to provide accurate, long term lung volume change measurements. Such a spirometer system is most suited for Deep Inspiration Breath-Hold (DIBH) treatments. An improved laser-spirometer combined system has also been developed for target tracking in 4-D treatment. Spirometer signals are used to calibrate the displacement measurements into lung volume changes, thereby eliminating scaling errors from daily setup variations. The laser displacement signals may also be used to correct spirometer drifts during operation. A new 4-D treatment technique has been developed to account for intrafraction motion in treatment planning. The patient's breathing and beam delivery are synchronized, and the target motion/deformation is incorporated into treatment plan optimization. Results show that this new 4-D treatment technique significantly reduces motion effects and provides improved patient tolerance.

  13. A Four-Dimensional Product Innovativeness Typology

    DEFF Research Database (Denmark)

    Rosenø, Axel

    2005-01-01

    ) typology with four newproduct types; Leonard-Barton's (1995) five product types; and Veryzer's (1998a)four types in a two-by-two matrix.Interestingly, these two meta-perspectives on product innovativeness (i.e. 1. new tothe market and/or new to the company and 2. technological and/or marketnewness...... discontinuous newproduct projects (Song & Montoya-Weiss 1998; Atuahene-Gima 1995; Veryzer 1998a;Lynn et al. 1996; O'Connor 1998; Rice et al. 1998). By looking at both these types ofnew product development projects, empirical observations are likely to be morerealistic than those of studies that do...... the dichotomous view and, thereby, lend themselves to a more finegrainedstudy of innovation management practices for different types of newproduct projects.In fact, various innovativeness typologies exist that include more than two producttypes. Notably, the typology by Booz, Allen & Hamilton (1982)2 introduces...

  14. Adaptive Motion Compensation in Radiotherapy

    CERN Document Server

    Murphy, Martin J

    2011-01-01

    External-beam radiotherapy has long been challenged by the simple fact that patients can (and do) move during the delivery of radiation. Recent advances in imaging and beam delivery technologies have made the solution--adapting delivery to natural movement--a practical reality. Adaptive Motion Compensation in Radiotherapy provides the first detailed treatment of online interventional techniques for motion compensation radiotherapy. This authoritative book discusses: Each of the contributing elements of a motion-adaptive system, including target detection and tracking, beam adaptation, and pati

  15. Radiotherapy on hidradenocarcinoma

    Directory of Open Access Journals (Sweden)

    Issam Lalya

    2011-01-01

    Full Text Available Context: Clear cell Hidradenocarcinoma is a rare carcinoma arising from sweat glands. It is an aggressive tumor that most metastasizes to regional lymph nodes and distant viscera; surgery with safe margins is the mainstay of treatment. Case Report: We report a case of 68-year-old woman who presented with an invasive clear cell hidradenocarcinoma situated in the left parotid area which recurred 5 months after surgery, this recurrence was managed successfully by high-dose irradiation of the tumor bed (66 Gy and regional lymphatic chains (50 Gy, after a follow-up of more than 15 months, the patient is in good local control without significant toxicity. Conclusion: Post operative radiotherapy allows better local control and should be mandatory when histological features predictive of recurrence are present: positive margins, histology poorly differentiated, perineural invasion, vascular and lymphatic invasion, lymph node involvement, and extracapsular spread.

  16. Radiotherapy on hidradenocarcinoma

    Directory of Open Access Journals (Sweden)

    Issam Lalya

    2011-01-01

    Full Text Available Context : Clear cell Hidradenocarcinoma is a rare carcinoma arising from sweat glands. It is an aggressive tumor that most metastasizes to regional lymph nodes and distant viscera; surgery with safe margins is the mainstay of treatment. Case Report: We report a case of 68-year-old woman who presented with an invasive clear cell hidradenocarcinoma situated in the left parotid area which recurred 5 months after surgery, this recurrence was managed successfully by high-dose irradiation of the tumor bed ( 66 Gy and regional lymphatic chains (50 Gy, after a follow-up of more than 15 months, the patient is in good local control without significant toxicity. Conclusion : Post operative radiotherapy allows better local control and should be mandatory when histological features predictive of recurrence are present: positive margins, histology poorly differentiated, perineural invasion, vascular and lymphatic invasion, lymph node involvement, and extracapsular spread.

  17. Anatomical imaging for radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Philip M [Joint Physics Department, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom)], E-mail: phil.evans@icr.ac.uk

    2008-06-21

    The goal of radiation therapy is to achieve maximal therapeutic benefit expressed in terms of a high probability of local control of disease with minimal side effects. Physically this often equates to the delivery of a high dose of radiation to the tumour or target region whilst maintaining an acceptably low dose to other tissues, particularly those adjacent to the target. Techniques such as intensity modulated radiotherapy (IMRT), stereotactic radiosurgery and computer planned brachytherapy provide the means to calculate the radiation dose delivery to achieve the desired dose distribution. Imaging is an essential tool in all state of the art planning and delivery techniques: (i) to enable planning of the desired treatment, (ii) to verify the treatment is delivered as planned and (iii) to follow-up treatment outcome to monitor that the treatment has had the desired effect. Clinical imaging techniques can be loosely classified into anatomic methods which measure the basic physical characteristics of tissue such as their density and biological imaging techniques which measure functional characteristics such as metabolism. In this review we consider anatomical imaging techniques. Biological imaging is considered in another article. Anatomical imaging is generally used for goals (i) and (ii) above. Computed tomography (CT) has been the mainstay of anatomical treatment planning for many years, enabling some delineation of soft tissue as well as radiation attenuation estimation for dose prediction. Magnetic resonance imaging is fast becoming widespread alongside CT, enabling superior soft-tissue visualization. Traditionally scanning for treatment planning has relied on the use of a single snapshot scan. Recent years have seen the development of techniques such as 4D CT and adaptive radiotherapy (ART). In 4D CT raw data are encoded with phase information and reconstructed to yield a set of scans detailing motion through the breathing, or cardiac, cycle. In ART a set of

  18. MRI assisted radiotherapy planning

    International Nuclear Information System (INIS)

    To obtain the optimal radiation field, an MR simulation system (MRSS) has been developed. The system consists of an MR unit, a work station and a laser marking system. Phantom study concerned geographic distortion and the total accuracy of MRSS, the former revealed the result lesser than 1 mm within 90 mm-distance between MR slices and Center of magnetic field, the latter showed maximal errors 2 mm in the field size, and 3 mm in the iso-center. This system was applied to 15 patients with intracranial or head and neck lesions and all procedures were smoothly performed. To evaluate the usefulness of MRSS, 6 radiation oncologists compared the difference between MRSS and CT simulation system in setting radiation field. The results were satisfactory especially in cases with lesions the extent of which was unclear on CT images. It was considered that this system could support the radiotherapy planning for intracranial or head and neck lesions. (author)

  19. [Hepatic tumors and radiotherapy].

    Science.gov (United States)

    Rio, E; Mornex, F; Peiffert, D; Huertas, A

    2016-09-01

    Recent technological developments led to develop the concept of focused liver radiation therapy. We must distinguish primary and secondary tumors as the indications are restricted and must be discussed as an alternative to surgical or medical treatments. For hepatocellular carcinoma 5 to 10cm (or more), a conformational radiation with or without intensity modulation is performed. Stereotactic body radiotherapy (SBRT) is being evaluated and is increasingly proposed as an alternative to radiofrequency ablative treatment for primary or secondary tumors (typically less than 5cm). Tumor (and liver) movements induced by respiratory motions must be taken into account. Strict dosimetric criteria must be met with particular attention to the dose-volume histograms to liver and the hollow organs, including cases of SBRT. PMID:27521035

  20. Classification, staging and radiotherapy of bronchial carcinoma

    International Nuclear Information System (INIS)

    This thesis reports a study performed to evaluate the stage classification of bronchial carcinoma published by Thomas in 1963. The study was done in the radiotherapy department of a teaching hospital, and had three parts: a comparative analysis of the classifications and stage divisions described in the literature on bronchial carcinoma; an evaluation of the theoretical basis of the classification system introduced by Thomas as well as of the practical applicability of the division into stages, with respect to the assessment of the prognosis and the choice of therapy; and an analysis of various aspects of irradiation as well as of a number of prognostic factors in bronchial carcinoma. (Auth.)

  1. Effect of different breathing patterns in the same patient on stereotactic ablative body radiotherapy dosimetry for primary renal cell carcinoma: A case study

    International Nuclear Information System (INIS)

    Stereotactic ablative body radiotherapy (SABR) for primary renal cell carcinoma (RCC) targets requires motion management strategies to verify dose delivery. This case study highlights the effect of a change in patient breathing amplitude on the dosimetry to organs at risk and target structures. A 73-year-old male patient was planned for receiving 26 Gy of radiation in 1 fraction of SABR for a left primary RCC. The patient was simulated with four-dimensional computed tomography (4DCT) and the tumor internal target volume (ITV) was delineated using the 4DCT maximum intensity projection. However, the initially planned treatment was abandoned at the radiation oncologist's discretion after pretreatment cone-beam CT (CBCT) motion verification identified a greater than 50% reduction in superior to inferior diaphragm motion as compared with the planning 4DCT. This patient was resimulated with respiratory coaching instructions. To assess the effect of the change in breathing on the dosimetry to the target, each plan was recalculated on the data set representing the change in breathing condition. A change from smaller to larger breathing showed a 46% loss in planning target volume (PTV) coverage, whereas a change from larger breathing to smaller breathing resulted in an 8% decrease in PTV coverage. ITV coverage was similarly reduced by 8% in both scenarios. This case study highlights the importance of tools to verify breathing motion prior to treatment delivery. 4D image guided radiation therapy verification strategies should focus on not only verifying ITV margin coverage but also the effect on the surrounding organs at risk

  2. Effect of different breathing patterns in the same patient on stereotactic ablative body radiotherapy dosimetry for primary renal cell carcinoma: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Daniel, E-mail: Daniel.Pham@petermac.org [Radiotherapy Services, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Kron, Tomas [Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Foroudi, Farshad; Siva, Shankar [Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia)

    2013-10-01

    Stereotactic ablative body radiotherapy (SABR) for primary renal cell carcinoma (RCC) targets requires motion management strategies to verify dose delivery. This case study highlights the effect of a change in patient breathing amplitude on the dosimetry to organs at risk and target structures. A 73-year-old male patient was planned for receiving 26 Gy of radiation in 1 fraction of SABR for a left primary RCC. The patient was simulated with four-dimensional computed tomography (4DCT) and the tumor internal target volume (ITV) was delineated using the 4DCT maximum intensity projection. However, the initially planned treatment was abandoned at the radiation oncologist's discretion after pretreatment cone-beam CT (CBCT) motion verification identified a greater than 50% reduction in superior to inferior diaphragm motion as compared with the planning 4DCT. This patient was resimulated with respiratory coaching instructions. To assess the effect of the change in breathing on the dosimetry to the target, each plan was recalculated on the data set representing the change in breathing condition. A change from smaller to larger breathing showed a 46% loss in planning target volume (PTV) coverage, whereas a change from larger breathing to smaller breathing resulted in an 8% decrease in PTV coverage. ITV coverage was similarly reduced by 8% in both scenarios. This case study highlights the importance of tools to verify breathing motion prior to treatment delivery. 4D image guided radiation therapy verification strategies should focus on not only verifying ITV margin coverage but also the effect on the surrounding organs at risk.

  3. Nutritional assistance to patients during radiotherapy

    International Nuclear Information System (INIS)

    With the aim of assessing the possible benefits of nutritional therapy , 140 patients were prospectively studied during radiotherapy of the head and neck (81%) and esophageal cancer (19%). Mean age was 56.0 (17-80), with 114 males and 26 females. Duration of both nutrition and radiotherapy was 78.0 ± 45 days. Tube feeding was the primary modality in 50.7% of the population, and oral regimens in the remaining 49.3%, but associations between the methods were also used. Enteral diets were supplied under the supervision of a specialized tem for home alimentation (PROSNED). Compliance to the program was 100% and a lymphocyte count diminished along this period (1933 ± 1033 vs 1265 ± 688, p.0.001). A subjective improvement was reported by 84% of the population, and total calorie intake, that was below 60% of estimated needs in 100% of the cases initially, significantly improved to just 40% inadequate at the end of the observations. Radiotherapy was associated with mucositis in 21% of the patients, taste changes in 79%, xerostomy in 81%, anorexia in 66% and odinophagia in 59%. In the individuals selected for enteral feeding, side effects were represented by technical problems (20%) and gastrointestinal disorders (13%). All patients completed the nutritional support program and there was no mortality in this series. It is conclude that: early nutritional support during radiotherapy was able to maintain or improve the nutritional status; tube feeding, alone or in combination with oral diets, was indicated whenever appropriate and contributed to fulfillment of the energy requirements; reduction of total lymphocytes could not be prevented by the mentioned therapy; complications of enteral alimentation were mild and affected a small proportion of the population; troubles induced by radiotherapy were as frequent as expected, and tended to disturb the intake of the food; the compliance of the therapeutic plan was excellent and can be attributed to the efforts of the

  4. Indications for Salivary Gland Radiotherapy.

    Science.gov (United States)

    Thomson, David J; Slevin, Nick J; Mendenhall, William M

    2016-01-01

    There is an established role for post-operative radiotherapy in the treatment of benign and malignant salivary gland tumours. For benign disease, the addition of radiotherapy improves local tumour control in cases with incomplete excision, involved surgical margins or multi-focal disease recurrence. After capsule rupture or spillage alone, surveillance should usually be advised. For malignant disease, post-operative radiotherapy is recommended for an advanced tumour stage, high-grade tumour, perineural or lympho-vascular invasion, close or positive resection margins, extra-parotid extension or lymph node involvement. The main benefit is increased loco-regional tumour control, although this may translate into a modest improvement in survival. The possible late side effects of parotid bed irradiation include skin changes, chronic otitis externa, sensorineural hearing loss, osteoradionecrosis and secondary malignancy. Severe complications are rare, but patients should be counselled carefully about the risks. Primary radiotherapy is unlikely to be curative and is reserved to cases in which resection would cause unacceptable functional or cosmetic morbidity or would likely result in subtotal resection (R2) or to patients with distant metastases to gain local tumour control. There are provisional data on the use of charged particle radiotherapy in this setting. Some patients may benefit from synchronous chemotherapy with radiotherapy, but this group is not defined, and data from comparative prospective studies are required before routine clinical use of this treatment. PMID:27093301

  5. Effects of radiotherapy on corticotrophic macro-tumors in dog

    International Nuclear Information System (INIS)

    A retrospective study was conducted to evaluate efficacy of low dose radiotherapy for treatment of pituitary corticotrophic macro-tumors in dogs. Twelve dogs with pituitary-dependent hyper-adrenocorticism and a large pituitary tumor treated with 36 Gy of radiation were included in this report. Radiation was delivered in twelve fractions of 3 Gy during a 4- week period. Effects of radiation therapy on tumor size were assessed by CT scans and a decrease was observed in ten dogs (decrease > 50% in four dogs). The mean and median survival times following the initiation of radiotherapy were 21,6 and 18 months, respectively. These cases support previous findings, based on high dose radiation, that radiotherapy is a valuable option in the treatment of pituitary corticotrophic macro-tumors in the dog. Use of smaller total dose and smaller dose fractions remains effective providing a cure with minimal side effects and allowing a second irradiation if necessary. (author)

  6. Long-term effects of radiotherapy for acromegaly on circulating prolactin

    Energy Technology Data Exchange (ETDEWEB)

    Ciccarelli, E.; Corsello, S.M.; Besser, G.M.; Wass, J.A.H. (Department of Endocrinology, St. Bartholomew' s Hospital, West Smithfield, London (UK)); Plowman, P.N.; Jones, A.E. (Department of Radiotherapy, St. Bartholomew' s Hospital, West Smithfield, London (UK)); Touzel, R.; Rees, L.H. (Department of Chemical Endocrinology, St. Bartholomew' s Hospital, West Smithfield, London (UK))

    1989-01-01

    In 61 acromegalic patients, serum PRL was assessed (off medical treatment) before and 2 to 12 (mean 6 p) years after external beam radiotherapy. Before radiotherapy elevated PRL levels were present in 22 of 35 males (63%) and 12 of 26 females (46%) and were above 1000 mU/l in 11 males and 5 females. When studied for up to 5 years after radiotherapy, 22 or 23 (96%) patients who had not had surgery and who had normal PRL preradiotherapy showed an increased PRL level and this was also seen in 17 or 27 (63%) who had hyperprolactinaemic initially. In contrast, 10 of 27 patients (37%) who had elevated pre-radiotherapy levels (all greater than 1000 mU/l) had a reduction in PRL values after radiotherapy. In all 11 patients who underwent surgery before radiotherapy, an increase in PRL was seen after radiotherapy. In the 21 patients followed for 10--12 years, the peak PRL value occurred 1--6 years after radiotherapy. After this, a progressive reduction of PRL to normal was seen. Normal levels were reached 4 to 10 years after radiotherapy. No correlation was found between pretreatment PRL values and final GH values in the whole group, nor between changes in PRL and the development of Impaired ACTH or TSH secretion. Thus, different patterns of PRL behaviour suggest that radiotherapy treatment may either produce hyperprolactinemia from mild hypothalamic damage or ablate PRL secreting cells if they were present in the tumour before treatment. These changes do not predict final GH results or the development of hypopituitarism after radiotherapy. (author).

  7. Long-term effects of radiotherapy for acromegaly on circulating prolactin

    International Nuclear Information System (INIS)

    In 61 acromegalic patients, serum PRL was assessed (off medical treatment) before and 2 to 12 (mean 6 p years after external beam radiotherapy. Before radiotherapy elevated PRL levels were present in 22 of 35 males (63%) and 12 of 26 females (46%) and were above 1000 mU/l in 11 males and 5 females. When studied for up to 5 years after radiotherapy, 22 or 23 (96%) patients who had not had surgery and who had normal PRL preradiotherapy showed an increased PRL level and this was also seen in 17 or 27 (63%) who had hyperprolactinaemic initially. In contrast, 10 of 27 patients (37%) who had elevated pre-radiotherapy levels (all greater than 1000 mU/l) had a reduction in PRL values after radiotherapy. In all 11 patients who underwent surgery before radiotherapy, an increase in PRL was seen after radiotherapy. In the 21 patients followed for 10-12 years, the peak PRL value occurred 1-6 years after radiotherapy. After this, a progressive reduction of PRL to normal was seen. Normal levels were reached 4 to 10 years after radiotherapy. No correlation was found between pretreatment PRL values and final GH values in the whole group, nor between changes in PRL and the development of Impaired ACTH or TSH secretion. Thus, different patterns of PRL behaviour suggest that radiotherapy treatment may either produce hyperprolactinemia from mild hypothalamic damage or ablate PRL secreting cells if they were present in the tumour before treatment. These changes do not predict final GH results or the development of hypopituitarism after radiotherapy. (author)

  8. Gene therapy and radiotherapy in malignant tumor

    International Nuclear Information System (INIS)

    Tumor treatment is one of the most important fields in medical research. Nowadays, a novel method which is combined gene therapy with radiotherapy plays an important role in the field of cancer research, and mainly includes immune gene therapy combined with radiotherapy, suicide gene therapy or tumor suppressor gene therapy combined with radiotherapy, antiangiogenesis gene therapy combined with radiotherapy and protective gene therapy combined with radiotherapy based on the technical features. This review summarized the current status of combined therapies of gene therapy and radiotherapy and possible mechanism. (authors)

  9. Dosimetric comparison of three-dimensional conformal radiotherapy, intensity modulated radiotherapy, and helical tomotherapy for lung stereotactic body radiotherapy

    Directory of Open Access Journals (Sweden)

    Rajesh Ashok Kinhikar

    2015-01-01

    Full Text Available To compare the treatment plans generated with three-dimensional conformal radiation therapy (3DCRT, intensity modulated radiotherapy (IMRT, and helical tomotherapy (HT for stereotactic body radiotherapy of lung, twenty patients with medically inoperable (early nonsmall cell lung cancer were retrospectively reviewed for dosimetric evaluation of treatment delivery techniques (3DCRT, IMRT, and HT. A dose of 6 Gy per fraction in 8 fractions was prescribed to deliver 95% of the prescription dose to 95% volume of planning target volume (PTV. Plan quality was assessed using conformity index (CI and homogeneity index (HI. Doses to critical organs were assessed. Mean CI with 3DCRT, IMRT, and HT was 1.19 (standard deviation [SD] 0.13, 1.18 (SD 0.11, and 1.08 (SD 0.04, respectively. Mean HI with 3DCRT, IMRT, and HT was 1.14 (SD 0.05, 1.08 (SD 0.02, and 1.07 (SD 0.04, respectively. Mean R50% values for 3DCRT, IMRT, and HT was 8.5 (SD 0.35, 7.04 (SD 0.45, and 5.43 (SD 0.29, respectively. D2cmwas found superior with IMRT and HT. Significant sparing of critical organs can be achieved with highly conformal techniques (IMRT and HT without compromising the PTV conformity and homogeneity.

  10. Dosimetric comparison of three-dimensional conformal radiotherapy, intensity modulated radiotherapy, and helical tomotherapy for lung stereotactic body radiotherapy.

    Science.gov (United States)

    Kinhikar, Rajesh Ashok; Ghadi, Yogesh G; Sahoo, Priyadarshini; Laskar, Sarbani Ghosh; Deshpande, Deepak D; Shrivastava, Shyam K; Agarwal, Jaiprakash

    2015-01-01

    To compare the treatment plans generated with three-dimensional conformal radiation therapy (3DCRT), intensity modulated radiotherapy (IMRT), and helical tomotherapy (HT) for stereotactic body radiotherapy of lung, twenty patients with medically inoperable (early nonsmall cell lung cancer) were retrospectively reviewed for dosimetric evaluation of treatment delivery techniques (3DCRT, IMRT, and HT). A dose of 6 Gy per fraction in 8 fractions was prescribed to deliver 95% of the prescription dose to 95% volume of planning target volume (PTV). Plan quality was assessed using conformity index (CI) and homogeneity index (HI). Doses to critical organs were assessed. Mean CI with 3DCRT, IMRT, and HT was 1.19 (standard deviation [SD] 0.13), 1.18 (SD 0.11), and 1.08 (SD 0.04), respectively. Mean HI with 3DCRT, IMRT, and HT was 1.14 (SD 0.05), 1.08 (SD 0.02), and 1.07 (SD 0.04), respectively. Mean R50% values for 3DCRT, IMRT, and HT was 8.5 (SD 0.35), 7.04 (SD 0.45), and 5.43 (SD 0.29), respectively. D2cm was found superior with IMRT and HT. Significant sparing of critical organs can be achieved with highly conformal techniques (IMRT and HT) without compromising the PTV conformity and homogeneity. PMID:26865754

  11. Radioprotectors in Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Nair, C.K.K. [Bhabha Atomic Research Centre, Mumbai (India); Parida, D.K.; Nomura, Taisei

    2001-03-01

    This review article focuses on clinically relevant radioprotectors and their mechanisms of radioprotection. Radiotherapy is the most common modality of human cancer therapy. Obtaining optimal results requires a judicious balance between the total dose of radiotherapy delivered and the threshold limit of critical surrounding normal tissues, and the normal tissues need to be protected against radiation injury to obtain better tumor control by using a higher dose. For this reason, radiation-protective agents play an important role in clinical radiotherapy. Radiation-protective agents can be classified into three groups: radioprotectors, adaptogens, and absorbents. The first group generally consists of sulfhydryl compounds and other antioxidants. They include several myelo-, entero-, and cerebro-protectors. Adaptogens act as promotors of radioresistance. They are natural protectors that offer chemical protection against low levels of ionizing radiation. Absorbents protect organs from internal radiation and chemicals. They include drugs that prevent incorporation of radioiodine by the thyroid gland and absorption of radionuclides. This article thoroughly describes the properties, mechanisms of action, and perspectives on clinical application of the following categories of radioprotectors: sulfhydryl compounds (e.g., cysteine, cysteamine, glutathione, AET, WR 2127, and other WR-compounds), antioxidants (e.g., tempace, Hoechst 33342, vitamin A, E, and C, TMG, melatonin), angiotensin-converting enzyme (ACE) inhibitors (e.g., captopril, elanopril, penicillamine, pentoxifylline, L-158, 809), cytoprotective agents (mesna, dexrazoxane, and amifostin), metalloelements (e.g., manganese chloride, cadmium salts, bismuth subnitrate), immunomodulators (gamma-interferon, polysaccharides AM5, AM218, heat-killed lactobacillus cells, broncho-vaxom, trehalose dicorynomycolate, and AS101), lipopolysaccharides and prostaglandins, plant extracts and compounds isolated from plants (curcmin

  12. A review of the results from the National Radiotherapy Patient Experience Survey in England

    International Nuclear Information System (INIS)

    Aim: The goal of the survey was to obtain a meaningful picture about patients' experiences across all radiotherapy centres within provider NHS trusts within England. Methods: A survey questionnaire was constructed to assess patients' views about their care, information and support at all stages of their radiotherapy pathway. The questionnaire was posted to patients who attended for radiotherapy within NHS trusts in England from April until December 2012. Key results: Many of the results were positive, for example 99% of patients had either complete confidence or confidence to some extent in the health care professional undertaking their consent. 97% of patients said that the amount of information given to them before their radiotherapy was either excellent or satisfactory. However there were 10% of patients who were not invited to an information session before radiotherapy, 14% of patients who were not told how to communicate with their radiographers whilst their treatment was delivered and 13% of patients who were not given a contact number to ring if they had any problems relating to their radiotherapy after finishing. Conclusions and recommendations: The results indicate that the majority of patients have experienced high quality care in many aspects of their radiotherapy pathway. However there are some areas where improvements could be made. It is recommended that all Radiotherapy Service Managers (RTSMs) review their local results and implement improvements where required and they re-audit on an annual basis. It is also recommended that the national survey is repeated at regular intervals to monitor progress

  13. A comparison of results by sequential and concurrent chemo radiotherapy in locally advanced carcinoma esophagus

    Directory of Open Access Journals (Sweden)

    V Bhandari

    2013-01-01

    Full Text Available Aim: Many Trials using sequential and concurrent chemo radiotherapy have been done so far and has established the role of concurrent chemo radiotherapy in treatment of inoperable carcinoma esophagus. In this study, we have compared the results of concurrent chemo radiotherapy with sequential chemo radiotherapy. We have treated inoperable carcinoma esophagus in both the settings and present here the comparison of results in the two settings. Materials and Methods: There were 26 patients of carcinoma esophagus in sequential and 31 in concurrent chemo radiotherapy arm. In sequential arm methotrexate and Cisplatin followed by radiotherapy was given whereas in concurrent arm, Cisplatin was given once weekly along with radiotherapy. Results: The 2 year survival was 38% in sequential and35.5% in the concurrent setting and the median survival was 19.5 and 18 months respectively in the two arms.The toxicities in both the arms were comparable. P value of 0.4774 with confidence interval of 95% was obtained, which is not significant. Dysphagia was improved earlier in sequential than in the concurrent arm. Conclusion: As the results and toxicities in both the arms are almost similar with better symptom control, so larger randomized trials are required to assess the response and the use of methotrexate in sequential chemo radiotherapy can be further explored.

  14. Factors influencing time between surgery and radiotherapy: A population based study of breast cancer patients.

    Science.gov (United States)

    Katik, S; Gort, M; Jobsen, J J; Maduro, J H; Struikmans, H; Siesling, S

    2015-08-01

    This study describes variation in the time interval between surgery and radiotherapy in breast cancer (BC) patients and assesses factors at patient, hospital and radiotherapy centre (RTC) level influencing this variation. To do so, the factors were investigated in BC patients using multilevel logistic regression. The study sample consisted of 15,961 patients from the Netherlands Cancer Registry at 79 hospitals and 19 (RTCs) with breast-conserving surgery or mastectomy directly followed by radiotherapy. The percentage of patients starting radiotherapy ≤42 days varied from 14% to 94%. Early year of incidence, higher age, higher stage, mastectomy, higher ASA category and no availability of radiotherapy facilities were significantly associated with a longer time interval between radiotherapy and surgery. More patients received radiotherapy ≤42 days in hospitals with on-site radiotherapy facilities (OR 1.36, p = 0.024). Among the remainder, significant variation was found at the RTC level (11.1%, σ(2) = 0.254, SE 0.054), and at the hospital level (6.4% σ2 = 0.443, SE 0.163) (ICC 0.064). The significant delay and unexplained variance remaining at the RCT and hospital level suggests delays caused by the patient referral pathway from hospital to RCT, and indicates potential for improvement at both levels.

  15. Adjuvant intensity-modulated proton therapy in malignant pleural mesothelioma. A comparison with intensity-modulated radiotherapy and a spot size variation assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lorentini, S. [Agenzia Provinciale per la Protonterapia (ATreP), Trento (Italy); Padova Univ. (Italy). Medical Physics School; Amichetti, M.; Fellin, F.; Schwarz, M. [Agenzia Provinciale per la Protonterapia (ATreP), Trento (Italy); Spiazzi, L. [Brescia Hospital (Italy). Medical Physics Dept.; Tonoli, S.; Magrini, S.M. [Brescia Hospital (Italy). Radiation Oncology Dept.

    2012-03-15

    Intensity-modulated radiation therapy (IMRT) is the state-of-the-art treatment for patients with malignant pleural mesothelioma (MPM). The goal of this work was to assess whether intensity-modulated proton therapy (IMPT) could further improve the dosimetric results allowed by IMRT. We re-planned 7 MPM cases using both photons and protons, by carrying out IMRT and IMPT plans. For both techniques, conventional dose comparisons and normal tissue complication probability (NTCP) analysis were performed. In 3 cases, additional IMPT plans were generated with different beam dimensions. IMPT allowed a slight improvement in target coverage and clear advantages in dose conformity (p < 0.001) and dose homogeneity (p = 0.01). Better organ at risk (OAR) sparing was obtained with IMPT, in particular for the liver (D{sub mean} reduction of 9.5 Gy, p = 0.001) and ipsilateral kidney (V{sub 20} reduction of 58%, p = 0.001), together with a very large reduction of mean dose for the contralateral lung (0.2 Gy vs 6.1 Gy, p = 0.0001). NTCP values for the liver showed a systematic superiority of IMPT with respect to IMRT for both the esophagus (average NTCP 14% vs. 30.5%) and the ipsilateral kidney (p = 0.001). Concerning plans obtained with different spot dimensions, a slight loss of target coverage was observed along with sigma increase, while maintaining OAR irradiation always under planning constraints. Results suggest that IMPT allows better OAR sparing with respect to IMRT, mainly for the liver, ipsilateral kidney, and contralateral lung. The use of a spot dimension larger than 3 x 3 mm (up to 9 x 9 mm) does not compromise dosimetric results and allows a shorter delivery time.

  16. Automatization in radiotherapy

    International Nuclear Information System (INIS)

    Data-processing in external radiotherapy has to be adapted to each local situation, taking into account the patients to be treated, the irradiation equipment, the data-processing centers available locally, regionally, and nationally, and the rentability of the data-processing system required. It should be recalled that most dosimetric methods used today can be treated manually, and the question of rentability has to be kept in mind when deciding to buy a data-processing system. The radiotherapist should, therefore, prepare a list of costs for each situation, and verify the validity of each programme proposed by the supplier. It is difficult to make a definite choice between the presently available systems. The radiotherapist has to choose in relation to his activity, his availability and the systems available to him. It can sometimes be more advantageous to have a terminal linked to a large computer, rather than to readapt a series of programmes for a data-processing system available locally: many such solutions, though original, cannot be 'exported'. It should be recalled that a large number of dosimetries can be obtained manually, and on the rare occasions when the aid of a computer is essential, the assistance of better equipped neighbouring centers can be obtained. The decision as to whether a data-processing system needs to be acquired has to take all these imperatives into account

  17. Quantitative assessment of inter-observer variability in target volume delineation on stereotactic radiotherapy treatment for pituitary adenoma and meningioma near optic tract

    International Nuclear Information System (INIS)

    To assess inter-observer variability in delineating target volume and organs at risk in benign tumor adjacent to optic tract as a quality assurance exercise. We quantitatively analyzed 21 plans made by 11 clinicians in seven CyberKnife centers. The clinicians were provided with a raw data set (pituitary adenoma and meningioma) including clinical information, and were asked to delineate the lesions and create a treatment plan. Their contouring and plans (10 adenoma and 11 meningioma plans), were then compared. In addition, we estimated the influence of differences in contouring by superimposing the respective contours onto a default plan. The median planning target volume (PTV) and the ratio of the largest to the smallest contoured volume were 9.22 cm3 (range, 7.17 - 14.3 cm3) and 1.99 for pituitary adenoma, and 6.86 cm3 (range 6.05 - 14.6 cm3) and 2.41 for meningioma. PTV volume was 10.1 ± 1.74 cm3 for group 1 with a margin of 1 -2 mm around the CTV (n = 3) and 9.28 ± 1.8 cm3(p = 0.51) for group 2 with no margin (n = 7) in pituitary adenoma. In meningioma, group 1 showed larger PTV volume (10.1 ± 3.26 cm3) than group 2 (6.91 ± 0.7 cm3, p = 0.03). All submitted plan keep the irradiated dose to optic tract within the range of 50 Gy (equivalent total doses in 2 Gy fractionation). However, contours superimposed onto the dose distribution of the default plan indicated that an excessive dose 23.64 Gy (up to 268% of the default plan) in pituitary adenoma and 24.84 Gy (131% of the default plan) in meningioma to the optic nerve in the contours from different contouring. Quality assurance revealed inter-observer variability in contour delineation and their influences on planning for pituitary adenoma and meningioma near optic tract

  18. Quantitative assessment of inter-observer variability in target volume delineation on stereotactic radiotherapy treatment for pituitary adenoma and meningioma near optic tract

    Directory of Open Access Journals (Sweden)

    Aibe Norihiro

    2011-01-01

    Full Text Available Abstract Background To assess inter-observer variability in delineating target volume and organs at risk in benign tumor adjacent to optic tract as a quality assurance exercise. Methods We quantitatively analyzed 21 plans made by 11 clinicians in seven CyberKnife centers. The clinicians were provided with a raw data set (pituitary adenoma and meningioma including clinical information, and were asked to delineate the lesions and create a treatment plan. Their contouring and plans (10 adenoma and 11 meningioma plans, were then compared. In addition, we estimated the influence of differences in contouring by superimposing the respective contours onto a default plan. Results The median planning target volume (PTV and the ratio of the largest to the smallest contoured volume were 9.22 cm3 (range, 7.17 - 14.3 cm3 and 1.99 for pituitary adenoma, and 6.86 cm3 (range 6.05 - 14.6 cm3 and 2.41 for meningioma. PTV volume was 10.1 ± 1.74 cm3 for group 1 with a margin of 1 -2 mm around the CTV (n = 3 and 9.28 ± 1.8 cm3(p = 0.51 for group 2 with no margin (n = 7 in pituitary adenoma. In meningioma, group 1 showed larger PTV volume (10.1 ± 3.26 cm3 than group 2 (6.91 ± 0.7 cm3, p = 0.03. All submitted plan keep the irradiated dose to optic tract within the range of 50 Gy (equivalent total doses in 2 Gy fractionation. However, contours superimposed onto the dose distribution of the default plan indicated that an excessive dose 23.64 Gy (up to 268% of the default plan in pituitary adenoma and 24.84 Gy (131% of the default plan in meningioma to the optic nerve in the contours from different contouring. Conclusion Quality assurance revealed inter-observer variability in contour delineation and their influences on planning for pituitary adenoma and meningioma near optic tract.

  19. Automated delineation of radiotherapy volumes: are we going in the right direction?

    Science.gov (United States)

    Whitfield, G A; Price, P; Price, G J; Moore, C J

    2013-01-01

    Rapid and accurate delineation of target volumes and multiple organs at risk, within the enduring International Commission on Radiation Units and Measurement framework, is now hugely important in radiotherapy, owing to the rapid proliferation of intensity-modulated radiotherapy and the advent of four-dimensional image-guided adaption. Nevertheless, delineation is still generally clinically performed with little if any machine assistance, even though it is both time-consuming and prone to interobserver variation. Currently available segmentation tools include those based on image greyscale interrogation, statistical shape modelling and body atlas-based methods. However, all too often these are not able to match the accuracy of the expert clinician, which remains the universally acknowledged gold standard. In this article we suggest that current methods are fundamentally limited by their lack of ability to incorporate essential human clinical decision-making into the underlying models. Hybrid techniques that utilise prior knowledge, make sophisticated use of greyscale information and allow clinical expertise to be integrated are needed. This may require a change in focus from automated segmentation to machine-assisted delineation. Similarly, new metrics of image quality reflecting fitness for purpose would be extremely valuable. We conclude that methods need to be developed to take account of the clinician's expertise and honed visual processing capabilities as much as the underlying, clinically meaningful information content of the image data being interrogated. We illustrate our observations and suggestions through our own experiences with two software tools developed as part of research council-funded projects.

  20. Dose reconstruction using respiratory signals and machine parameters during treatment in stereotactic body radiotherapy

    International Nuclear Information System (INIS)

    Volumetric modulated arc therapy (VMAT) is a rotational intensity-modulated radiotherapy (IMRT) technique capable of acquiring projection images during treatment. The purpose of this study was to reconstruct the dose distribution from respiratory signals and machine parameters acquired during stereotactic body radiotherapy (SBRT). The treatment plans created for VMAT-SBRT included the constraint of 1 mm/degree in multileaf collimator (MLC) for a moving phantom and three patients with lung tumors. The respiratory signals were derived from projection images acquired during VMAT delivery, while the machine parameters were derived from machine logs. The respiratory signals and machine parameters were then linked along with the gantry angle. With this data, the dose distribution of each respiratory phase was calculated on the planned four-dimensional CT (4DCT). The doses at the isocenter, the point of max dose and the centroid of the target were compared with those of the corresponding plans. In the phantom study, the maximum dose difference between the plan and 'in-treatment' results was -0.4% at the centroid of the target. In the patient study, the difference was -1.8%±0.4% at the centroid of the target. Dose differences of the evaluated points between 4 and 10 phases were not significant. The present method successfully reconstructed the dose distribution using the respiratory signals and machine parameters acquired during treatment. This is a feasible method for verifying the actual dose for a moving target. (author)

  1. Efficacy of low-dose radiotherapy in painful gonarthritis: experiences from a retrospective East German bicenter study

    Directory of Open Access Journals (Sweden)

    Keller Stephanie

    2013-01-01

    Full Text Available Abstract Purpose To evaluate the efficacy of low-dose radiotherapy in painful gonarthritis. Methods We assessed the medical records of 1037 patients with painful gonarthritis who had undergone low-dose radiotherapy between 1981 and 2008. The subjective patient perception of the response to irradiation as graded immediately or up to two months after the completion of a radiotherapy series was evaluated and correlated with age, gender, radiological grading and the duration of symptoms before radiotherapy. Moreover, we performed a mail survey to obtain additional long-term follow-up information and received one hundred and six evaluable questionnaires. Results We assessed 1659 series of radiotherapy in 1037 patients. In 79.3% of the cases the patients experienced a slight, marked or complete pain relief immediately or up to two months after the completion of radiotherapy. Gender, age and the duration of pain before radiotherapy did not have a significant influence on the response to irradiation. In contrast, severe signs of osteoarthritis were associated with more effective pain relief. In more than 50% of the patients who reported a positive response to irradiation a sustained period of symptomatic improvement was observed. Conclusions Our results confirm that low-dose radiotherapy is an effective treatment for painful osteoarthritis of the knee. In contrast to an earlier retrospective study, severe signs of osteoarthritis constituted a positive prognostic factor for the response to irradiation. A randomized trial is urgently required to compare radiotherapy with other treatment modalities.

  2. Efficacy of low-dose radiotherapy in painful gonarthritis: experiences from a retrospective East German bicenter study

    International Nuclear Information System (INIS)

    To evaluate the efficacy of low-dose radiotherapy in painful gonarthritis. We assessed the medical records of 1037 patients with painful gonarthritis who had undergone low-dose radiotherapy between 1981 and 2008. The subjective patient perception of the response to irradiation as graded immediately or up to two months after the completion of a radiotherapy series was evaluated and correlated with age, gender, radiological grading and the duration of symptoms before radiotherapy. Moreover, we performed a mail survey to obtain additional long-term follow-up information and received one hundred and six evaluable questionnaires. We assessed 1659 series of radiotherapy in 1037 patients. In 79.3% of the cases the patients experienced a slight, marked or complete pain relief immediately or up to two months after the completion of radiotherapy. Gender, age and the duration of pain before radiotherapy did not have a significant influence on the response to irradiation. In contrast, severe signs of osteoarthritis were associated with more effective pain relief. In more than 50% of the patients who reported a positive response to irradiation a sustained period of symptomatic improvement was observed. Our results confirm that low-dose radiotherapy is an effective treatment for painful osteoarthritis of the knee. In contrast to an earlier retrospective study, severe signs of osteoarthritis constituted a positive prognostic factor for the response to irradiation. A randomized trial is urgently required to compare radiotherapy with other treatment modalities

  3. Small animal radiotherapy research platforms

    International Nuclear Information System (INIS)

    Advances in conformal radiation therapy and advancements in pre-clinical radiotherapy research have recently stimulated the development of precise micro-irradiators for small animals such as mice and rats. These devices are often kilovolt x-ray radiation sources combined with high-resolution CT imaging equipment for image guidance, as the latter allows precise and accurate beam positioning. This is similar to modern human radiotherapy practice. These devices are considered a major step forward compared to the current standard of animal experimentation in cancer radiobiology research. The availability of this novel equipment enables a wide variety of pre-clinical experiments on the synergy of radiation with other therapies, complex radiation schemes, sub-target boost studies, hypofractionated radiotherapy, contrast-enhanced radiotherapy and studies of relative biological effectiveness, to name just a few examples. In this review we discuss the required irradiation and imaging capabilities of small animal radiation research platforms. We describe the need for improved small animal radiotherapy research and highlight pioneering efforts, some of which led recently to commercially available prototypes. From this, it will be clear that much further development is still needed, on both the irradiation side and imaging side. We discuss at length the need for improved treatment planning tools for small animal platforms, and the current lack of a standard therein. Finally, we mention some recent experimental work using the early animal radiation research platforms, and the potential they offer for advancing radiobiology research. (topical review)

  4. Small animal radiotherapy research platforms

    Science.gov (United States)

    Verhaegen, Frank; Granton, Patrick; Tryggestad, Erik

    2011-06-01

    Advances in conformal radiation therapy and advancements in pre-clinical radiotherapy research have recently stimulated the development of precise micro-irradiators for small animals such as mice and rats. These devices are often kilovolt x-ray radiation sources combined with high-resolution CT imaging equipment for image guidance, as the latter allows precise and accurate beam positioning. This is similar to modern human radiotherapy practice. These devices are considered a major step forward compared to the current standard of animal experimentation in cancer radiobiology research. The availability of this novel equipment enables a wide variety of pre-clinical experiments on the synergy of radiation with other therapies, complex radiation schemes, sub-target boost studies, hypofractionated radiotherapy, contrast-enhanced radiotherapy and studies of relative biological effectiveness, to name just a few examples. In this review we discuss the required irradiation and imaging capabilities of small animal radiation research platforms. We describe the need for improved small animal radiotherapy research and highlight pioneering efforts, some of which led recently to commercially available prototypes. From this, it will be clear that much further development is still needed, on both the irradiation side and imaging side. We discuss at length the need for improved treatment planning tools for small animal platforms, and the current lack of a standard therein. Finally, we mention some recent experimental work using the early animal radiation research platforms, and the potential they offer for advancing radiobiology research.

  5. Radiotherapy and skin tumors; Radiotherapie et tumeurs curanees

    Energy Technology Data Exchange (ETDEWEB)

    Calitchi, E.; KIrova, Y.; Le bourgeois, J.P. [Hopital Henri-Mondor, 94 - Creteil (France)

    1998-09-01

    Radiotherapy plays an important role in treatment of skin tumours. For skin carcinomas, external irradiation (kilo-voltage X-rays or electrons according to clinical characteristics) is more valuable than interstitial brachytherapy, which is recommended for tumours of the lip and of the nasal vestibule. In mycosis fungoides, total cutaneous electron beam radiation therapy is efficient for patients with limited superficial plaques. In the classical form of Kaposi`s sarcoma, radiotherapy can achieve local control-whereas it obtains good palliative results in the epidemic form. (author)

  6. WEE1 inhibition sensitizes osteosarcoma to radiotherapy

    Directory of Open Access Journals (Sweden)

    Helder Marco N

    2011-04-01

    Full Text Available Abstract Background The use of radiotherapy in osteosarcoma (OS is controversial due to its radioresistance. OS patients currently treated with radiotherapy generally are inoperable, have painful skeletal metastases, refuse surgery or have undergone an intralesional resection of the primary tumor. After irradiation-induced DNA damage, OS cells sustain a prolonged G2 cell cycle checkpoint arrest allowing DNA repair and evasion of cell death. Inhibition of WEE1 kinase leads to abrogation of the G2 arrest and could sensitize OS cells to irradiation induced cell death. Methods WEE1 expression in OS was investigated by gene-expression data analysis and immunohistochemistry of tumor samples. WEE1 expression in OS cell lines and human osteoblasts was investigated by Western blot. The effect of WEE1 inhibition on the radiosensitivity of OS cells was assessed by cell viability and caspase activation analyses after combination treatment. The presence of DNA damage was visualized using immunofluorescence microscopy. Cell cycle effects were investigated by flow cytometry and WEE1 kinase regulation was analyzed by Western blot. Results WEE1 expression is found in the majority of tested OS tissue samples. Small molecule drug PD0166285 inhibits WEE1 kinase activity. In the presence of WEE1-inhibitor, irradiated cells fail to repair their damaged DNA, and show higher levels of caspase activation. The inhibition of WEE1 effectively abrogates the irradiation-induced G2 arrest in OS cells, forcing the cells into premature, catastrophic mitosis, thus enhancing cell death after irradiation treatment. Conclusion We show that PD0166285, a small molecule WEE1 kinase inhibitor, can abrogate the G2 checkpoint in OS cells, pushing them into mitotic catastrophe and thus sensitizing OS cells to irradiation-induced cell death. This suggests that WEE1 inhibition may be a promising strategy to enhance the radiotherapy effect in patients with OS.

  7. Technological advances in radiotherapy for esophageal cancer

    Institute of Scientific and Technical Information of China (English)

    Milan; Vosmik; Jiri; Petera; Igor; Sirak; Miroslav; Hodek; Petr; Paluska; Jiri; Dolezal; Marcela; Kopacova

    2010-01-01

    Radiotherapy with concurrent chemotherapy and surgery represent the main treatment modalities in esophageal cancer.The goal of modern radiotherapy approaches,based on recent technological advances,is to minimize post-treatment complications by improving the gross tumor volume definition (positron emission tomography-based planning),reducing interfraction motion (image-guided radiotherapy) and intrafraction motion (respiratory-gated radiotherapy),and by better dose delivery to the precisely defined planning ...

  8. Prospective longitudinal assessment of parotid gland function using dynamic quantitative pertechnate scintigraphy and estimation of dose–response relationship of parotid-sparing radiotherapy in head-neck cancers

    International Nuclear Information System (INIS)

    To estimate dose–response relationship using dynamic quantitative 99mTc-pertechnate scintigraphy in head-neck cancer patients treated with parotid-sparing conformal radiotherapy. Dynamic quantitative pertechnate salivary scintigraphy was performed pre-treatment and subsequently periodically after definitive radiotherapy. Reduction in salivary function following radiotherapy was quantified by salivary excretion fraction (SEF) ratios. Dose–response curves were modeled using standardized methodology to calculate tolerance dose 50 (TD50) for parotid glands. Salivary gland function was significantly affected by radiotherapy with maximal decrease in SEF ratios at 3-months, with moderate functional recovery over time. There was significant inverse correlation between SEF ratios and mean parotid doses at 3-months (r = −0.589, p < 0.001); 12-months (r = −0.554, p < 0.001); 24-months (r = −0.371, p = 0.002); and 36-months (r = −0.350, p = 0.005) respectively. Using a post-treatment SEF ratio <45% as the scintigraphic criteria to define severe salivary toxicity, the estimated TD50 value with its 95% confidence interval (95% CI) for the parotid gland was 35.1Gy (23.6-42.6Gy), 41.3Gy (34.6-48.8Gy), 55.9Gy (47.4-70.0Gy) and 64.3Gy (55.8-70.0Gy) at 3, 12, 24, and 36-months respectively. There is consistent decline in parotid function even after conformal radiotherapy with moderate recovery over time. Dynamic quantitative pertechnate scintigraphy is a simple, reproducible, and minimally invasive test of major salivary gland function. The online version of this article (doi:10.1186/s13014-015-0371-2) contains supplementary material, which is available to authorized users

  9. Cost calculation: a necessary step towards widespread adoption of advanced radiotherapy technology.

    Science.gov (United States)

    Lievens, Yolande; Borras, Jose Maria; Grau, Cai

    2015-01-01

    Radiotherapy costs are an often underestimated component of the economic assessment of new radiotherapy treatments and technologies. That the radiotherapy budget only consumes a finite part of the total cancer and healthcare budget does not relieve us from our responsibility to balance the extra costs to the additional benefits of new, more advanced, but typically also more expensive treatments we want to deliver. Yet, in contrast to what is the case for oncology drugs, literature evidence remains limited, as well for economic evaluations comparing new radiotherapy interventions as for cost calculation studies. Even more cumbersome, the available costing studies in the field of radiotherapy fail to accurately capture the real costs of our treatments due to the large variation in cost inputs, in scope of the analysis, in costing methodology. And this is not trivial. Accurate resource cost accounting lays the basis for the further steps in health technology assessment leading to radiotherapy investments and reimbursement, at the local, the national and the worldwide level. In the current paper we review some evidence from the existing costing literature and discuss how such data can be used to support reimbursement setting and investment cases for new radiotherapy equipment and infrastructure.

  10. Changes in sexual function after radiotherapy treatment of prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Beckendorf, V. [Centre Alexis Vautrin, Vandoeuvre-les Nancy (France); Hay, M. [Centre Val d`Aurelle, Montpellier (France); Rozan, R. [Centre Jean Perrin, Clermont-Ferrand (France); Lagrange, J.L. [Centre Antoine Lacassagne, Nice (France); N`Guyen, T. [Centre Jean Godinot, Reims (France); Giraud, B. [CCMI Commission de Cooperation Medicale Intercentres, Centre Hospitalier Univ. et Centre Jean Perrin, Clement-Ferrand (France)

    1996-01-01

    The objective was to assess sexual function before and after definitive irradiation for the treatment of cancer of the prostate. The study comprised 67 patients (mean age 68 years) treated in five radiotherapy departments and assessed with repeated questionnaires about their libido, arousal, frequency and quality of intercourse, and sexual satisfaction. Interviews were obtained before radiotherapy and at the end of the first year after treatment. Sixty-three patients were married and 50 had a sexually effective partner. Forty-six patients presented with another pathology or medical treatment capable of inducing sexual dysfunction. Before radiotherapy, 40 patients were sexually active, with good to acceptable intercourse. Between 10 and 24 months after the end of radiotherapy, no disease progression was observed and prostate-specific antigen levels remained high in only two patients. Sexual function was preserved in 67% of patients but only 50% observed no change. The functional prognosis seemed to be related to the initial frequency and quality of intercourse; more than three times per month, the prognosis remained good, under three per month, it was poor. The patient`s age was a predictive factor for the frequency of intercourse. (author).

  11. Unilateral Radiotherapy for the Treatment of Tonsil Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chronowski, Gregory M., E-mail: gchronowski@mdanderson.org [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Garden, Adam S.; Morrison, William H.; Frank, Steven J. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Schwartz, David L. [Department of Radiation Medicine, Long Island Jewish Hospital (United States); Shah, Shalin J.; Beadle, Beth M.; Gunn, G. Brandon [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Kupferman, Michael E. [Department of Head and Neck Surgery, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Ang, Kian K.; Rosenthal, David I. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

    2012-05-01

    Purpose: To assess, through a retrospective review, clinical outcomes of patients with squamous cell carcinoma of the tonsil treated at the M. D. Anderson Cancer Center with unilateral radiotherapy techniques that irradiate the involved tonsil region and ipsilateral neck only. Methods and Materials: Of 901 patients with newly diagnosed squamous cell carcinoma of the tonsil treated with radiotherapy at our institution, we identified 102 that were treated using unilateral radiotherapy techniques. All patients had their primary site of disease restricted to the tonsillar fossa or anterior pillar, with <1 cm involvement of the soft palate. Patients had TX (n = 17 patients), T1 (n = 52), or T2 (n = 33) disease, with Nx (n = 3), N0 (n = 33), N1 (n = 23), N2a (n = 21), or N2b (n = 22) neck disease. Results: Sixty-one patients (60%) underwent diagnostic tonsillectomy before radiotherapy. Twenty-seven patients (26%) underwent excision of a cervical lymph node or neck dissection before radiotherapy. Median follow-up for surviving patients was 38 months. Locoregional control at the primary site and ipsilateral neck was 100%. Two patients experienced contralateral nodal recurrence (2%). The 5-year overall survival and disease-free survival rates were 95% and 96%, respectively. The 5-year freedom from contralateral nodal recurrence rate was 96%. Nine patients required feeding tubes during therapy. Of the 2 patients with contralateral recurrence, 1 experienced an isolated neck recurrence and was salvaged with contralateral neck dissection only and remains alive and free of disease. The other patient presented with a contralateral base of tongue tumor and involved cervical lymph node, which may have represented a second primary tumor, and died of disease. Conclusions: Unilateral radiotherapy for patients with TX-T2, N0-N2b primary tonsil carcinoma results in high rates of disease control, with low rates of contralateral nodal failure and a low incidence of acute toxicity

  12. Hyperthermia and radiotherapy

    International Nuclear Information System (INIS)

    Combined hyperthermia (HT 45 min once or twice per week) and low dose radiotherapy (LDRT 30-34.5 Gy in 2-3 weeks) have been given to 182 locally recurrent or metastatic superficial tumours in 133 patients. Tumour response was analysed in 137 tumours in 100 patients. The overall complete response (CR) was 50% with a median duration (DCR) of 13±3 months. When mammary carcinoma, representing 62% of the treated tumours, were analysed, CR was 62% with a DCR of 14±4 months. In a comparative, non-randomized study, on 34 matched tumour pairs in 24 patients, treatment was given with LDRT+HT to the larger and the same LDRT to the smaller tumour, the patients acting as their own control. A significant difference in CR was obtained in favour of the combined treatment (p=0.0013 all diagnosis and p=0.0027 mammary carcinoma). There was no significant difference in DCR between the two modalities. No significant difference in CR was seen when tumours were randomely treated with HT once (CR 56%) or twice (CR 69%) per week combined with the same LDRT. Predictive factors for CR, multivariately analysed (15 parameters), in mammary carcinoma recurring in earlier irradiated regions, were; the present LDRT absorbed dose (p=0.02) and the average minimum temperature in the best HT session (p=0.03). Significant skin toxicity was seen in 28% of all the 182 heated regions. Prognostic factors for skin damage, multivariately analysed, were; the extension of the heated region (p=0.007) and the highest average maximum temperature in any of the HT sessions (p=0.04). Pain was in some way correlated to severe toxicity but was not considered to be an optimal monitor for HT as many patients with severe and moderate pain were without any serious skin reactions, while slight or no pain sometimes were associated with severe reactions. 401 refs

  13. Mucosal regeneration during radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: Regeneration of the aerodigestive mucosa is known to occur during conventionally fractionated radiotherapy. The circumstances surrounding its time of onset and magnitude are not well understood, however. Material and methods: Mucosal reactions were observed in 100 patients undergoing conventionally fractionated treatment at 2 Gy/day over 7 weeks and 88 receiving accelerated treatment at 1.8 Gy twice daily over 3(1(2)) weeks on the Trans Tasman Radiation Oncology Group head and neck cancer trials. Similar observations in 61 patients treated palliatively at dose rates between 0.8 and 240 Gy/h using ten 3.0-4.2 Gy fractions over 2 weeks are compared. Results: Several findings emerged from these studies: 1. Reactions evolved more quickly at oropharyngeal sites than in the hypopharynx. 2. Reactions at both sites evolved more rapidly at greater rates of dose accumulation. 3. The timing of reactions suggested the presence of a strong regenerative mucosal response that started before the manifestation of 'patchy' (grade II) mucosal reactions. 4. The regenerative response was strong enough to 'make good' damage accumulated at a rate of 2 Gy/day in over a third of cases. 5. The linear quadratic model without time correction failed to provide an adequate prediction of the frequency or intensity of mucosal reactions produced by any of the regimes. A simple model of the regenerative response is presented. Conclusions: This study suggests that the timing and magnitude of the regenerative response vary between sites and individuals but are linked to the amount of epithelial cellular depletion occurring during treatment

  14. Dosimetry in radiotherapy. V.2

    International Nuclear Information System (INIS)

    A series of symposia on dosimetry in medicine and biology have been held by the IAEA in co-operation with WHO. The present symposium was the first one focusing on ''Dosimetry in Radiotherapy''. The papers presented reflected the different steps in the calibration chain such as the calibration standards established by the National Standards Laboratories and the conversion of the reading of calibrated instruments to the desired quantity, i.e. absorbed dose to water at a reference point in the user's beam at the radiotherapy clinic. The programme further examined the procedures necessary for optimization of the treatment of the patient, such as treatment planning methods, dose distribution studies, new techniques of dose measurement, improvements in the physical dose distributions/conformation therapy and special problems involved in total body treatments. Results of quality assurance in radiotherapy were presented from local hospitals as well as from national and international studies. Refs, figs and tabs

  15. Dosimetry in radiotherapy. V.1

    International Nuclear Information System (INIS)

    A series of symposia on dosimetry in medicine and biology have been held by the IAEA in co-operation with WHO. The present symposium was the first one focusing on ''Dosimetry in Radiotherapy''. The papers presented reflected the different steps in the calibration chain such as the calibration standards established by the National Standards Laboratories and the conversion of the reading of calibrated instruments to the desired quantity, i.e. absorbed dose to water at a reference point in the user's beam at the radiotherapy clinic. The programme further examined the procedures necessary for optimization of the treatment of the patient, such as treatment planning methods, dose distribution studies, new techniques of dose measurement, improvements in the physical dose distributions/conformation therapy and special problems involved in total body treatments. Results of quality assurance in radiotherapy were presented from local hospitals as well as from national and international studies. Refs, figs and tabs

  16. Computerised tomography in radiotherapy planning

    International Nuclear Information System (INIS)

    This study evaluates the effectiveness of computed tomography as an adjunct to radiotherapy planning. Until recently, acquisition of accurate data concerning tumour anatomy lagged behind other developments in radiotherapy. With the advent of computer-tomography (CT), these data can be displayed and transmitted to a treatment planning computer. It is concluded that the greatest inaccuracies in the radiation treatment of patients are to be found in both the inadequate delineation of the target volume within the patient and changes in body outline relative to the target volume over the length of the irradiated volume. The technique was useful in various subgroups (pelvic, intra-thoracic and chest-wall tumours) and for those patients being treated palliatively. With an estimated improvement in cure rate of 4.5% and cost-effective factors of between 3.3 and 5, CT-assisted radiotherapy planning appears to be a worthwhile procedure. (orig.)

  17. Baseline Utilization of Breast Radiotherapy Before Institution of the Medicare Practice Quality Reporting Initiative

    International Nuclear Information System (INIS)

    Purpose: In 2007, Medicare implemented the Physician Quality Reporting Initiative (PQRI), which provides financial incentives to physicians who report their performance on certain quality measures. PQRI measure no. 74 recommends radiotherapy for patients treated with conservative surgery (CS) for invasive breast cancer. As a first step in evaluating the potential impact of this measure, we assessed baseline use of radiotherapy among women diagnosed with invasive breast cancer before implementation of PQRI. Methods and Materials: Using the SEER-Medicare data set, we identified women aged 66-70 diagnosed with invasive breast cancer and treated with CS between 2000 and 2002. Treatment with radiotherapy was determined using SEER and claims data. Multivariate logistic regression tested whether receipt of radiotherapy varied significantly across clinical, pathologic, and treatment covariates. Results: Of 3,674 patients, 94% (3,445) received radiotherapy. In adjusted analysis, the presence of comorbid illness (odds ratio [OR] 1.69; 95% confidence interval [CI], 1.19-2.42) and unmarried marital status were associated with omission of radiotherapy (OR 1.65; 95% CI, 1.22-2.20). In contrast, receipt of chemotherapy was protective against omission of radiotherapy (OR 0.25; 95% CI, 0.16-0.38). Race and geographic region did not correlate with radiotherapy utilization. Conclusions: Utilization of radiotherapy following CS was high for patients treated before institution of PQRI, suggesting that at most 6% of patients could benefit from measure no. 74. Further research is needed to determine whether institution of PQRI will affect radiotherapy utilization.

  18. Technological problems in the use of research fast reactors for radiotherapy of patients with malignant tumors

    International Nuclear Information System (INIS)

    The authors discuss the technological problems associated with the use of fast neutrons in radiotherapy of cancer patients and outline the approaches to the solution of these problems. The state of the art is assessed. Physical and radiobiologial prerequisites for the use of fast reactors for radiotherapy of patients with malignant tumors are analyzed. Results of clinic used of BR-10 reactor at the Medical Radiology Research Center, Russian Academy of Medical Sciences, are presented. Experimental and clinical findings indicate that the results of radiotherapy may be appreaciably improved if a novel perspective source of fast neutrons, a nuclear reactor, is used

  19. Experience of the Casablanca radiotherapy-oncology centre on radiotherapy in the treatment of the adult Hodgkin lymphoma; Experience du centre de radiotherapie-oncologie de Casablanca sur la radiotherapie dans le traitement du lymphome de Hodgkin de l'adulte

    Energy Technology Data Exchange (ETDEWEB)

    Bouchbika, Z.; Benchakroun, N.; Sellai, N.; Jouhadi, H.; Tawfiq, N.; Sahraoui, S.; Benider, A. [Service radiotherapie-oncologie, CHU Ibn-Rochd, Casablanca (Morocco)

    2011-10-15

    The authors report the assessment of the local control, global survival and survival without recurrence, and also late complications, based on retrospective study over 8 years of 169 cases Hodgkin lymphoma in patients older than 18 (average age of 34) and who had been submitted to radiotherapy. Survival has been computed according to the Kaplan-Meier method. The authors notice that the recurrence rate is slightly higher than in the literature. During the considered period, radiotherapy was two-dimensional with higher doses than those corresponding to current standards. The improvement of radiotherapy techniques and the decrease of doses within the standards should improve the therapeutic results. Short communication

  20. Infrastructure for radiotherapy in the Netherlands: development from 1970 to 2010

    International Nuclear Information System (INIS)

    In 1993 the radiotherapy advisory committee of the Dutch Health Council published its report on the developments of infrastructure for radiotherapy in The Netherlands during the last 10 years and the prognosis for future needs until 2010. Based on demographic trends, the expected incidence of cancer, the role of radiotherapy in the treatment of cancer, and the workload assessment in a model department, two scenarios are presented for the development of infrastructure. According to the committee, the Quality Scenario would be the most appropriate

  1. Computed Tomography-Based Anatomic Assessment Overestimates Local Tumor Recurrence in Patients With Mass-like Consolidation After Stereotactic Body Radiotherapy for Early-Stage Non-Small Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dunlap, Neal E. [Department of Radiation Oncology, University of Louisville, Louisville, KY (United States); Yang Wensha [Department of Radiation Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States); McIntosh, Alyson [Department of Radiation Oncology, John and Dorothy Morgan Cancer Center, Lehigh Valley Hospital, Allentown, PA (United States); Sheng, Ke [Department of Radiation Oncology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA (United States); Benedict, Stanley H.; Read, Paul W. [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Larner, James M., E-mail: jml2p@virginia.edu [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States)

    2012-12-01

    Purpose: To investigate pulmonary radiologic changes after lung stereotactic body radiotherapy (SBRT), to distinguish between mass-like fibrosis and tumor recurrence. Methods and Materials: Eighty consecutive patients treated with 3- to 5-fraction SBRT for early-stage peripheral non-small cell lung cancer with a minimum follow-up of 12 months were reviewed. The mean biologic equivalent dose received was 150 Gy (range, 78-180 Gy). Patients were followed with serial CT imaging every 3 months. The CT appearance of consolidation was defined as diffuse or mass-like. Progressive disease on CT was defined according to Response Evaluation Criteria in Solid Tumors 1.1. Positron emission tomography (PET) CT was used as an adjunct test. Tumor recurrence was defined as a standardized uptake value equal to or greater than the pretreatment value. Biopsy was used to further assess consolidation in select patients. Results: Median follow-up was 24 months (range, 12.0-36.0 months). Abnormal mass-like consolidation was identified in 44 patients (55%), whereas diffuse consolidation was identified in 12 patients (15%), at a median time from end of treatment of 10.3 months and 11.5 months, respectively. Tumor recurrence was found in 35 of 44 patients with mass-like consolidation using CT alone. Combined with PET, 10 of the 44 patients had tumor recurrence. Tumor size (hazard ratio 1.12, P=.05) and time to consolidation (hazard ratio 0.622, P=.03) were predictors for tumor recurrence. Three consecutive increases in volume and increasing volume at 12 months after treatment in mass-like consolidation were highly specific for tumor recurrence (100% and 80%, respectively). Patients with diffuse consolidation were more likely to develop grade {>=}2 pneumonitis (odds ratio 26.5, P=.02) than those with mass-like consolidation (odds ratio 0.42, P=.07). Conclusion: Incorporating the kinetics of mass-like consolidation and PET to the current criteria for evaluating posttreatment response will

  2. 基于四维顾客价值的航空客运市场细分模型研究%Research on Market Segmentation Model of Air Passenger Transport Based on the Four-dimensional Customer Value

    Institute of Scientific and Technical Information of China (English)

    王悦; 曾小舟; 陈桥

    2015-01-01

    旨在根据航空运输行业特点以及以顾客价值为导向的市场销售特征,摒弃传统细分变量以及细分方法的使用,从Kotler四维顾客总价值角度构建航空客运市场细分模型;继而形成施测问卷,获取样本数据;将因子分析与经典的K-Means相结合,最终获得四类差距明显的子市场.研究结果表明,依据构建的市场细分模型能够获得较为满意的市场细分结果,验证了模型的有效性,可作为航空客运主体细分市场的依据之一.%According to the industry features of the civil aviation and its customer-oriented marketing characteris-tics, this paper established an efficient model of market segmentation (MS) based on Kotler's four-dimensional to-tal customer value (TCV), casting away the traditional segmentation variables and methods. On the basis of the es-tablished model, a questionnaire was formed and the correspondent data were collected. Combining the factor anal-ysis and the classic K-Means algorithm, this paper finally obtained four segmented markets with significant differ-ences. Results demonstrated that according to the constructed model, a desirable segmentation result was ac-quired, which might verify the validity of the model and thus could be the reference for MS of the operational sub-jects in civil aviation.

  3. Performance of different radiotherapy workload models

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was to evaluate the performance of different radiotherapy workload models using a prospectively collected dataset of patient and treatment information from a single center. Methods and Materials: Information about all individual radiotherapy treatments was collected for 2 weeks from the three linear accelerators (linacs) in our department. This information included diagnosis code, treatment site, treatment unit, treatment time, fields per fraction, technique, beam type, blocks, wedges, junctions, port films, and Eastern Cooperative Oncology Group (ECOG) performance status. We evaluated the accuracy and precision of the original and revised basic treatment equivalent (BTE) model, the simple and complex Addenbrooke models, the equivalent simple treatment visit (ESTV) model, fields per hour, and two local standards of workload measurement. Results: Data were collected for 2 weeks in June 2001. During this time, 151 patients were treated with 857 fractions. The revised BTE model performed better than the other models with a mean vertical bar observed - predicted vertical bar of 2.62 (2.44-2.80). It estimated 88.0% of treatment times within 5 min, which is similar to the previously reported accuracy of the model. Conclusion: The revised BTE model had similar accuracy and precision for data collected in our center as it did for the original dataset and performed the best of the models assessed. This model would have uses for patient scheduling, and describing workloads and case complexity

  4. Clinical Observation of the Application of the Four-dimensional Color Doppler Ultrasound Examination in Diagnosis of Abnormal Development of Fetus%胎儿发育异常应用四维彩超检查诊断的临床观察

    Institute of Scientific and Technical Information of China (English)

    丁连霞

    2015-01-01

    目的:观察分析胎儿发育异常采用四维彩超检查诊断的效果。方法针对我院妇产科收治的500例孕周中晚期孕妇,分别采用二维彩超和四维彩超实施产前胎儿检查,对比检测结果。结果四维超声诊断符合率明显优于二维彩超,P<0.05。结论采用四维彩超诊断胎儿发育异常,诊断准确率较高。%Objective To observe and analyze the abnormal development of fetus by four-dimensional color doppler ultrasound examination diagnosis effect. Methods In 500 patients with advanced gestational weeks pregnant women in our hospital were treated respectively by the department of obstetrics and gynecology, two-dimensional ultrasound and the four-dimensional color doppler ultrasound examination of the implementation of prenatal, comparison. Results The rate is higher than that of two-dimensional color doppler ultrasound diagnosis accord with four-dimensional, P<0.05. Conclusion Using the four-dimensional color doppler ultrasound in the diagnosis of fetal abnormalities, diagnosis accuracy rate.

  5. Construction of a remote radiotherapy planning system

    International Nuclear Information System (INIS)

    We constructed a remote radiotherapy planning system, and we examined the usefulness of and faults in our system in this study. Two identical radiotherapy planning systems, one installed at our institution and the other installed at an affiliated hospital, were used for radiotherapy planning. The two systems were connected by a wide area network (WAN), using a leased line. Beam data for the linear accelerator at the affiliated hospital were installed in the two systems. During the period from December 2001 to December 2002, 43 remote radiotherapy plans were made using this system. Data were transmitted using a file transfer protocol (FTP) software program. The 43 radiotherapy plans examined in this study consisted of 13 ordinary radiotherapy plans, 28 radiotherapy plans sent to provide assistance for medical residents, and 2 radiotherapy plans for emergency cases. There were ten minor planning changes made in radiotherapy plans sent to provide assistance for medical residents. Our remote radiotherapy planning system based on WAN using a leased line is useful for remote radiotherapy, with advantages for both radiation oncologists and medical residents. (author)

  6. Surgery or radiotherapy for the treatment of bone hydatid disease: a retrospective case series

    Directory of Open Access Journals (Sweden)

    Zengru Xie

    2015-04-01

    Conclusion: This retrospective case series describes, for the first time, the clinical outcomes in a series of patients treated with radiotherapy for bone hydatid disease. Although no direct comparison between the treatment groups could be made due to methodological limitations of the study design, this study indicates that well-designed prospective randomized controlled clinical trials assessing radiotherapy may be warranted in patients with inoperable hydatid disease of the bones.

  7. The relationship between serum vitamin A and breast cancer staging before and after radiotherapy

    OpenAIRE

    Andréa Matos; Carla Nogueira; Carlos Franca; Antônio Carvalho; Sérgio Lannes Vieira; Antônio Penna; Andréa Ramalho

    2014-01-01

    Introduction: Several adverse effects of radiotherapy have been associated with the process of increased oxidative stress in the organism. In this context, vitamin A noteworthy for its important role in combating oxidative stress, in addition to its chemoprotective effect. Objective: To assess the serum levels of vitamin A (retinol and β-carotene) and their relationship to breast cancer staging in patients before and after radiotherapy. Methods: This is a prospective study of women with breas...

  8. Thalassaemic osteoarthropathy treated with radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Davies, A.N. (King' s Coll. Hospital, London (United Kingdom))

    1993-11-01

    Patients with beta thalassaemia may develop a specific osteoarthropathy involving the feet. A number of different treatments for this condition have been tried, including rest, analgesia and hypertransfusion. We report a case of a patient with thalassaemic osteoarthropathy who responded to radiotherapy after failing conventional treatment. (author).

  9. Computerised tomography in radiotherapy planning

    NARCIS (Netherlands)

    P.C. Badcock (Peter)

    1983-01-01

    textabstractSuccessful radiotherapy practice depends on the irradiation of tumours such that their destruction follows without unacceptable damage of the surrounding normal tissues. Until recently the accurate acquisition of data concerning the tumour anatomy lagged behind other developments in radi

  10. Clinical radiotherapy audits in Belgium, 2011-2014.

    Science.gov (United States)

    Scalliet, P G M

    2015-10-01

    Systematic clinical radiotherapy audits have been introduced in Belgium in 2011, as part of the Federal Cancer Plan. This is in compliance with article 11 of the 97/43 Council directive of Euratom states, translated into the Belgian legislation by royal decree in 2002. The principle of clinical audits has thus been part of the federal legal requirements for more than 10 years. However, its application had to wait for the development of a practical approach: what authority will audit, who will be the auditors, along which methodology, at what frequency, etc. Since 2002, the Federal College of Radiotherapy has the mission to monitor quality of radiotherapy at large. It was therefore decided after discussions with the relevant administration at the Ministry of Health and the Federal Agency for Nuclear Control that the College would practically organise the audits. Early in the 2000s, the IAEA developed a manual for comprehensive audits, as a tool for quality improvement. Auditors were professionals of the domain and the audit visit took the form of a peer review. Great care was taken to assemble an audit party able to cover all aspects of clinical radiotherapy with a radiation oncologist, a medical physicist, a radiation therapist and, on demand, a quality officer. The IAEA manual contains a series of questionnaires to be prepared by the audited centre in advance (pre-audit and self-assessment), indicating what specific areas the auditors would assess. It is also a template for the auditors, ensuring that no area is left aside or forgotten during the site visit. The report, at the end of the visit, is drafted according to a specific report template, also developed by IAEA. Several members of the Belgian radiotherapy community have developed their auditor's skills by participating to the IAEA audit program; they are the core of the auditor Belgian team. PMID:26321683

  11. The influence of radiotherapy on cosmetic outcome after breast conservative surgery

    International Nuclear Information System (INIS)

    Purpose: The influence of radiotherapy in the cosmetic outcome after conservative surgery for breast cancer was evaluated using an objective method of calculating the asymmetry between the two breasts. Methods and Materials: One hundred and one patients treated with the same conservative surgery were evaluated for cosmetic outcome. Sixty-one of them received external radiotherapy (50 + 10 Gy) to the residual breast; the remaining 40 underwent surgery only. The aspect of the patients' breasts was objectively assessed for symmetry by means of a computerized technique. A subjective assessment of the cosmetic outcome was performed both by physician and patient. These objective and subjective assessments were compared in the two groups treated with or without radiotherapy. Results: The results obtained did not show significant differences in terms of cosmetic outcome in the two groups. Skin telangectasia was noted in two radiotherapy patients, while hypertrophic breast scars were only noted in six nonirradiated patients. Conclusions: We found that standard radiotherapy does not seem to influence the symmetry and the cosmetic results in breast conservative treatment when compared to a similar group of patients with the same quadrantectomy procedure and no radiotherapy

  12. Effect of fractionated regional external beam radiotherapy on peripheral blood cell count

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was to assess the need for obtaining weekly complete blood count (CBC) values and to identify the pattern of changes in CBC during regional conventional fractionated radiotherapy. Methods and Materials: A retrospective analysis of CBC data on 299 adult cancer patients who received definitive conventional radiotherapy to head and neck (n=95), chest (n=96), and pelvis (n=108) was performed. Temporal patterns and magnitude of change in white blood cells, neutrophils, lymphocytes, and platelets during radiotherapy were examined. Results: There were statistically significant declines in all counts, albeit not clinically significant. Notable differences between disease sites were found. The greatest weekly interval change in counts occurred during the first week of radiotherapy for all groups of patients. The mean WBC nadir values during treatment were 5.8 for head and neck, 6.8 for chest, and 5.4 for pelvis. The nadirs for all counts occurred toward the middle-to-end of radiotherapy. Lymphocytes were found to be more sensitive to radiotherapy than other leukocyte subcomponents. Conclusion: Our study suggests that weekly CBC monitoring is not necessary for all patients undergoing standard fractionated radiotherapy. Baseline blood counts may be used to determine an optimal schedule for monitoring CBCs in patients receiving conventional radiation alone. Reduced monitoring of CBC may result in significant financial savings

  13. Effect of radiotherapy on the sealing ability of temporary filling materials

    Directory of Open Access Journals (Sweden)

    Ebru Hazar Bodrumlu

    2015-01-01

    Full Text Available Objective: The purpose of this study was to assess the sealing ability of three different temporary restorative materials on endodontic access cavities as compared to radiated and nonirradiated teeth. Materials and Methods: All teeth were randomly divided into two main groups according to the presence or absence of the radiotherapy. The specimens in these groups were then divided into three subgroups of 12 teeth each, and into two control groups of eight teeth each as negative and positive control groups. In radiotherapy groups, radiotherapy (1.8 Gy was applied daily over 35 days resulting in a total application of 63 Gy. Standardized occlusal endodontic access cavities were prepared in all groups. A cotton pellet was placed on the pulp chamber. The access cavities were restored with three temporary filling materials; first fill, Cavit-G and Cavisol. The specimens were immersed in 2% methylene blue solution and centrifuged at 3000 rpm for 5 min. Results: Although there was no statistical difference among the three materials for the groups in which radiotherapy was not applied (P > 0.05, it was found that the sealing abilities of Cavit-G and Cavisol were not affected by radiotherapy (P > 0.05. However, the leakage values of the light-cured polymerized temporary filling material, first fill, were increased when radiotherapy was performed (P < 0.05. Conclusion: The radiotherapy application reduces the sealing ability of the light-cured temporary filling material, first fill.

  14. Locoregional radiotherapy in patients with distant metastases of nasopharyngeal carcinoma at diagnosis

    Institute of Scientific and Technical Information of China (English)

    Ming-Yuan Chen; Li Zhang; Ming-Huang Hong; Hai-Qiang Mai; Chao-Nan Qian; Rou Jiang; Ling Guo; Xiong Zou; Qing Liu; Rui Sun; Fang Qiu; Zhong-Jun Xia; Hui-Qiang Huang

    2013-01-01

    Systemic chemotherapy is the basic palliative treatment for metastatic nasopharyngeal carcinoma (NPC); however, it is not known whether locoregional radiotherapy targeting the primary tumor and regional lymph nodes affects the survival of patients with metastatic NPC. Therefore, we aimed to retrospectively evaluate the benefits of locoregional radiotherapy. A total of 408 patients with metastatic NPC were included in this study. The mortality risks of the patients undergoing supportive treatment and those undergoing chemotherapy were compared with that of patients undergoing locoregional radiotherapy delivered alone or in combination with chemotherapy. Univariate and multivariate analyses were conducted. The contributions of independent factors were assessed after adjustment for covariates with significant prognostic associations (P<0.05). Both locoregional radiotherapy and systemic chemotherapy were identified as significant independent prognostic factors of overall survival (OS). The mortality risk was similar in the group undergoing locoregional radiotherapy alone and the group undergoing systemic chemotherapy alone [multi-adjusted hazard ratio (HR) = 0.9, P = 0.529]; this risk was 60% lower than that of the group undergoing supportive treatment (HR = 0.4, P = 0.004) and 130% higher than that of the group undergoing both systemic chemotherapy and locoregional radiotherapy (HR = 2.3, P < 0.001). In conclusion, locoregional radiotherapy, particularly when combined with systemic chemotherapy, is associated with improved survival of patients with metastatic NPC.

  15. A Mathematical Model of Tumor Volume Changes during Radiotherapy

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    Ping Wang

    2013-01-01

    Full Text Available Purpose. To develop a clinically viable mathematical model that quantitatively predicts tumor volume change during radiotherapy in order to provide treatment response assessment for prognosis, treatment plan optimization, and adaptation. Method and Materials. The correction factors containing hypoxia, DNA single strand breaks, potentially lethal damage, and other factors were used to develop an improved cell survival model based on the popular linear-quadratic model of cell survival in radiotherapy. The four-level cell population model proposed by Chvetsov et al. was further simplified by removing the initial hypoxic fraction and reoxygenation parameter, which are hard to obtain in routine clinics, such that an easy-to-use model can be developed for clinical applications. The new model was validated with data of nine lung and cervical cancer patients. Results. Out of the nine cases, the new model can predict tumor volume change in six cases with a correlation index R2 greater than 0.9 and the rest of three with R2 greater than 0.85. Conclusion. Based on a four-level cell population model, a more practical and simplified cell survival curve was proposed to model the tumor volume changes during radiotherapy. Validation study with patient data demonstrated feasibility and clinical usefulness of the new model in predicting tumor volume change in radiotherapy.

  16. Complete remission of localised gastric plasmacytomas following definitive radiotherapy

    International Nuclear Information System (INIS)

    Primary gastric extramedullary plasmacytoma is an extremely rare condition and there is scant information in the literature concerning its natural history or therapy. There have been anecdotal reports of surgical resection, with or without Helicobacter pylori eradication, but there are no useful reports of the role of radiotherapy. We report the clinicopathologic outcome of radical radiotherapy as a primary treatment modality. We identified two patients with biopsy-proven primary gastric extramedullary plasmacytoma. Routine staging investigations were performed and H. pylori status was determined. Radical radiotherapy to 41.4 Gy in 23 fractions was delivered using conformal techniques. The target volume was the stomach with a 1-cm margin. Prophylactic anti-emetic was administered prior to each fraction. Post-treatment endoscopies and biopsies were performed at 3-monthly intervals to assess clinicopathological response. Treatment-related toxicities were documented. Both patients achieved durable (>12 months) pathologically confirmed complete remissions without significant toxicities. Radical radiotherapy offers the potential for cure and organ preservation with low toxicity. It should be considered a favourable alternative to surgery in the management of this rare disease entity.

  17. [Exclusive radiotherapy and concurrent endocrine therapy for the management of elderly breast cancer patients: case study and review of hypofractionated schemes].

    Science.gov (United States)

    Auberdiac, P; Chargari, C; Cartier, L; Mélis, A; Malkoun, N; Chauleur, C; Jacquin, J-P; de Laroche, G; Magné, N

    2011-12-01

    Normofractionated radiotherapy is standard for adjuvant management of patients treated with breast conservative surgery for breast cancer. However, many elderly patients are not eligible to such strategy, either because of concurrent diseases, or because the tumor is inoperable. Several protocols of exclusive radiotherapy have been reported in the literature, frequently using hypofractionated radiotherapy and endocrine therapy. We report a case of a patient treated with exclusive endocrine and radiotherapy and address the state of the art on hypofractionated schemes for the management of elderly breast cancer patients. While hypofractionated radiotherapy does not compromise the oncologic or cosmetic outcome, there is no prospective data that assesses the place of radiotherapy for the exclusive treatment of elderly patients. This strategy should be further assessed in clinical randomized trial.

  18. Detecting depressive and anxiety disorders in distressed patients in primary care; comparative diagnostic accuracy of the Four-Dimensional Symptom Questionnaire (4DSQ and the Hospital Anxiety and Depression Scale (HADS

    Directory of Open Access Journals (Sweden)

    Verhaak Peter FM

    2009-08-01

    Full Text Available Abstract Background Depressive and anxiety disorders often go unrecognized in distressed primary care patients, despite the overtly psychosocial nature of their demand for help. This is especially problematic in more severe disorders needing specific treatment (e.g. antidepressant pharmacotherapy or specialized cognitive behavioural therapy. The use of a screening tool to detect (more severe depressive and anxiety disorders may be useful not to overlook such disorders. We examined the accuracy with which the Four-Dimensional Symptom Questionnaire (4DSQ and the Hospital Anxiety and Depression Scale (HADS are able to detect (more severe depressive and anxiety disorders in distressed patients, and which cut-off points should be used. Methods Seventy general practitioners (GPs included 295 patients on sick leave due to psychological problems. They excluded patients with recognized depressive or anxiety disorders. Patients completed the 4DSQ and HADS. Standardized diagnoses of DSM-IV defined depressive and anxiety disorders were established with the Composite International Diagnostic Interview (CIDI. Receiver Operating Characteristic (ROC analyses were performed to obtain sensitivity and specificity values for a range of scores, and area under the curve (AUC values as a measure of diagnostic accuracy. Results With respect to the detection of any depressive or anxiety disorder (180 patients, 61%, the 4DSQ and HADS scales yielded comparable results with AUC values between 0.745 and 0.815. Also with respect to the detection of moderate or severe depressive disorder, the 4DSQ and HADS depression scales performed comparably (AUC 0.780 and 0.739, p 0.165. With respect to the detection of panic disorder, agoraphobia and social phobia, the 4DSQ anxiety scale performed significantly better than the HADS anxiety scale (AUC 0.852 versus 0.757, p 0.001. The recommended cut-off points of both HADS scales appeared to be too low while those of the 4DSQ anxiety

  19. Radiotherapy of acne - a literature survey

    International Nuclear Information System (INIS)

    This review is part of a feasibility study on a follow-up survey of patients having undergone dermatologic X-ray therapy. Its main purpose is to bring up to date the knowledge on the long-term effects of the radiotherapy of seborrheic diseases and to collect any historical data contributing to the interpretation of the results of a future survey in this field. The older and modern physiopathogenic ideas on acne are first stated, and both the radiological protocols and the therapeutic associations set forth by roentgenologists in the years 1930-1960 are then described. A dosimetric and health assessment is made and the modalities of an epidemiological survey are considered

  20. 血清 CEA、CYFAR21-1、SCC、CA125水平对晚期非小细胞肺癌放疗疗效的评估价值%Assessment Value of Serum CEA,CYFAR21-1,SCC,CA125 Levels in Efficacy of Radiotherapy for Advanced Non-small Cell Lung Cancer

    Institute of Scientific and Technical Information of China (English)

    阿合力·那斯肉拉; 巴尔夏古丽·扎比胡拉; 穆朝东

    2014-01-01

    目的:探讨血清肿瘤标志物水平对晚期非小细胞肺癌患者放疗疗效的评估价值。方法将晚期非小细胞肺癌患者共176例,分为观察组(近期放疗有效)和对照组(近期放疗无效),采用电化学发光法检测放疗前、后血清肿瘤CEA、CYFAR21-1、SCC、CA125水平。结果176例患者放疗有效率为58.0%,观察组放疗前血清CEA、CYFAR21-1、SCC、CA125水平分别为(33.65±5.41)ng/ml、(19.44±3.14)ng/ml、(16.87±2.74)ng/ml、(46.81±5.49)U/ml,放疗后各项标志物水平分别为(25.13±4.65)ng/ml、(12.35±4.18)ng/ml、(11.77±3.04)ng/ml、(39.67±4.63)U/ml,均明显低于放疗前,差异均有统计学意义(P<0.05);对照组放疗前血清肿瘤标志物CEA、CYFAR21-1、SCC、CA125水平分别为(46.87±5.93)ng/ml、(28.63±10.82)ng/ml、(26.46±8.68)ng/ml、(68.16±7.38)U/ml,放疗后各项标志物水平分别为(52.17±5.49)ng/ml、(46.72±11.75)ng/ml、(38.74±63.48)ng/ml、(87.34±8.16)U/ml,均明显高于放疗前,差异均有统计学意义(P<0.05);观察组放疗前各项标志物水平均低于对照组,差异显著(P<0.05);对照组放疗后标志物水平降低患者的近期疗效明显好于放疗后血清肿瘤标志物水平升高者,差异有统计学意义(χ2=76.45,P<0.05)。结论肿瘤血清肿瘤标志物CEA、CYFAR21-1、SCC、CA125的水平对晚期非小细胞肺癌患者放疗疗效具有评估价值。%Objective To explore the assessment value of serum level of tumor markers in efficacy of radiotherapy for advanced non-small cell lung cancer .Methods 176 cases of advanced non-small cell lung cancer were divided into 2 groups:the observation group ( recent radiotherapy effective ) and the control group ( recent radiotherapy invalid ) , tumor

  1. Palliative radiotherapy: current status and future directions.

    Science.gov (United States)

    Sharma, Sonam; Hertan, Lauren; Jones, Joshua

    2014-12-01

    For nearly 100 years, palliative radiotherapy has been a time-efficient, effective treatment for patients with metastatic or advanced cancer in any area where local tumors are causing symptoms. Short courses including a single fraction of radiotherapy may be effective for symptom relief with minimal side effects and maximization of convenience for patient and family. With recent advances in imaging, surgery, and other local therapies as well as systemic cancer therapies, palliative radiotherapy has been used frequently in patients who may not yet have symptoms of advanced or metastatic cancer. In this setting, more prolonged radiotherapy courses and advanced radiotherapy techniques including intensity-modulated radiotherapy (IMRT) or stereotactic radiotherapy (SRT) may be useful in obtaining local control and durable palliative responses. This review will explore the use of radiotherapy across the spectrum of patients with advanced and metastatic cancer and delineate an updated, rational approach for the use of palliative radiotherapy that incorporates symptoms, prognosis, and other factors into the delivery of palliative radiotherapy. PMID:25499634

  2. High-risk endometrial cancer may be benefit from adjuvant radiotherapy plus chemotherapy

    Institute of Scientific and Technical Information of China (English)

    Jin-Wei Miao; Xiao-Hong Deng

    2012-01-01

    Objective:To present patterns of practice and outcomes in the adjuvant treatment of intermediate-and high-risk endometrial cancer.Methods:Retrospective data on 224 women with intermediate-risk and high-risk endometrial cancer from 1999 to 2006 were reviewed.All patients underwent surgical staging.Patterns of adjuvant treatment,consisting of pelvic radiotherapy,chemotherapy,and radiotherapy plus chemotherapy,were assessed.The 3-and 5-year disease-specific survival (DSS) rates were calculated using the Kaplan-Meier method.Results:The difference in 5-year DSS rate was statistically significant between adjuvant group and non-adjuvant group (80.65% vs.63.80%,P=0.040).In 110 high-risk patients who underwent adjuvant treatment,both 5-year DSS rate and recurrent rate were significantly different in combined radiotherapy and chemotherapy group compared with radiotherapy alone and chemotherapy alone groups (DSS rate,P=0.049; recurrent rate,P=0.047).In 83 intermediate-risk women who underwent adjuvant treatment,there was no significant difference in 5-year DSS rate and recurrence rate among the combined radiotherapy and chemotherapy,radiotherapy alone and chemotherapy alone groups (DSS rate,P=0.776; recurrent rate,P=0.937).Conclusions:Adjuvant radiotherapy plus chemotherapy is associated with a higher 5-year DSS rate and lower recurrence rate compared with radiotherapy alone and chemotherapy alone in high-risk endometrial cancer patients.Patients with intermediate-risk endometrial cancer may be not likely to benefit from adjuvant combined radiotherapy and chemotherapy.

  3. Vectorized radiotherapy of neuro-endocrine tumors: decision approach between Mibg-iodine 131 and ostreoscan; Radiotherapie vectorisee des tumeurs neuro-endocrines metastasees: demarche decisionnelle entre MIBG-iode-131 et octreoscan

    Energy Technology Data Exchange (ETDEWEB)

    Giraudet, A.L

    2002-10-15

    In a first time are reminded what are the N.E.T. ( neuro-endocrine tumors), the vectorized radiotherapy with the great principles of radiotherapy as cancers treatment and the description of the two most used radiopharmaceuticals. Then, is described the pre-treatment assessment, its foundation and its results got near 19 patients. Then are discussed the different points arisen during the assessment. (N.C.)

  4. Intensity modulated radiotherapy and 3D conformal radiotherapy for whole breast irradiation: a comparative dosimetric study and introduction of a novel qualitative index for plan evaluation, the normal tissue index

    OpenAIRE

    Yim, Jackie; Suttie, Clare; Bromley, Regina; Morgia, Marita; Lamoury, Gillian

    2015-01-01

    Introduction We report on a retrospective dosimetric study, comparing 3D conformal radiotherapy (3DCRT) and hybrid intensity modulated radiotherapy (hIMRT). We evaluated plans based on their planning target volume coverage, dose homogeneity, dose to organs at risk (OARs) and exposure of normal tissue to radiation. The Homogeneity Index (HI) was used to assess the dose homogeneity in the target region, and we describe a new index, the normal tissue index (NTI), to assess the dose in the normal...

  5. Patterns of retreatment with radiotherapy in a large academic centre

    International Nuclear Information System (INIS)

    To characterise retreatment rates with radiotherapy at a large multifacility academic radiotherapy centre and assess the effect of distance on retreatment rate. Electronic administrative records were reviewed for patients receiving radiotherapy between 1998 and 2010 at regional and metropolitan facilities. Course-level data were reconstructed from electronic administrative databases. Intent of therapy, treatment dates and diagnosis were available for analysis. Retreatment characteristics were derived, including proportion of patients receiving retreatment, proportion of total radiotherapy prescriptions dedicated to retreatment and retreatment per treating facility. Travel distance for each patient to their treatment centre was estimated, and retreatment rates were reported as a function of increasing distance. A total of 48,200 patients were treated with 66,277 treatment courses during the study period. Retreatment courses constituted 25.2% of all courses prescribed. During the study period, 20.4% of all patients received at least one treatment course. Of these, the average number of retreatment courses prescribed was 1.84. Patients treated with radical intent had a retreatment rate of 13% compared with 45% for those treated initially with palliative intent. Retreatment rates in individual tumour sites ranged from 1.3 to 44.4%. The retreatment rate for those living less than 100km from treatment facility was 24.8%, and 20.5% for those living more than 100km from treatment centre (P<0.001) Retreatment accounted for over one quarter of radiotherapy courses, with the rate influenced by casemix and follow-up duration. With increasing distance from treatment centre, a decrease in retreatment rate was observed.

  6. Hyperfractionated or accelerated radiotherapy in head and neck cancer: a meta-analysis

    DEFF Research Database (Denmark)

    Bourhis, J.; Overgaard, Jens; Audry, H.;

    2006-01-01

    BACKGROUND: Several trials have studied the role of unconventional fractionated radiotherapy in head and neck squamous cell carcinoma, but the effect of such treatment on survival is not clear. The aim of this meta-analysis was to assess whether this type of radiotherapy could improve survival......-specified categories: hyperfractionated, accelerated, and accelerated with total dose reduction. FINDINGS: 15 trials with 6515 patients were included. The median follow-up was 6 years. Tumours sites were mostly oropharynx and larynx; 5221 (74%) patients had stage III-IV disease (International Union Against Cancer...... radiotherapy (2% with accelerated fractionation without total dose reduction and 1.7% with total dose reduction at 5 years, p=0.02). There was a benefit on locoregional control in favour of altered fractionation versus conventional radiotherapy (6.4% at 5 years; p<0.0001), which was particularly efficient in...

  7. Functional Image-Guided Radiotherapy Planning in Respiratory-Gated Intensity-Modulated Radiotherapy for Lung Cancer Patients With Chronic Obstructive Pulmonary Disease

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Tomoki, E-mail: tkkimura@hiroshima-u.ac.jp [Department of Radiation Oncology, Hiroshima University, Graduate School of Biomedical Sciences, Hiroshima City (Japan); Nishibuchi, Ikuno; Murakami, Yuji; Kenjo, Masahiro; Kaneyasu, Yuko; Nagata, Yasushi [Department of Radiation Oncology, Hiroshima University, Graduate School of Biomedical Sciences, Hiroshima City (Japan)

    2012-03-15

    Purpose: To investigate the incorporation of functional lung image-derived low attenuation area (LAA) based on four-dimensional computed tomography (4D-CT) into respiratory-gated intensity-modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT) in treatment planning for lung cancer patients with chronic obstructive pulmonary disease (COPD). Methods and Materials: Eight lung cancer patients with COPD were the subjects of this study. LAA was generated from 4D-CT data sets according to CT values of less than than -860 Hounsfield units (HU) as a threshold. The functional lung image was defined as the area where LAA was excluded from the image of the total lung. Two respiratory-gated radiotherapy plans (70 Gy/35 fractions) were designed and compared in each patient as follows: Plan A was an anatomical IMRT or VMAT plan based on the total lung; Plan F was a functional IMRT or VMAT plan based on the functional lung. Dosimetric parameters (percentage of total lung volume irradiated with {>=}20 Gy [V20], and mean dose of total lung [MLD]) of the two plans were compared. Results: V20 was lower in Plan F than in Plan A (mean 1.5%, p = 0.025 in IMRT, mean 1.6%, p = 0.044 in VMAT) achieved by a reduction in MLD (mean 0.23 Gy, p = 0.083 in IMRT, mean 0.5 Gy, p = 0.042 in VMAT). No differences were noted in target volume coverage and organ-at-risk doses. Conclusions: Functional IGRT planning based on LAA in respiratory-guided IMRT or VMAT appears to be effective in preserving a functional lung in lung cancer patients with COPD.

  8. Functional Image-Guided Radiotherapy Planning in Respiratory-Gated Intensity-Modulated Radiotherapy for Lung Cancer Patients With Chronic Obstructive Pulmonary Disease

    International Nuclear Information System (INIS)

    Purpose: To investigate the incorporation of functional lung image-derived low attenuation area (LAA) based on four-dimensional computed tomography (4D-CT) into respiratory-gated intensity-modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT) in treatment planning for lung cancer patients with chronic obstructive pulmonary disease (COPD). Methods and Materials: Eight lung cancer patients with COPD were the subjects of this study. LAA was generated from 4D-CT data sets according to CT values of less than than −860 Hounsfield units (HU) as a threshold. The functional lung image was defined as the area where LAA was excluded from the image of the total lung. Two respiratory-gated radiotherapy plans (70 Gy/35 fractions) were designed and compared in each patient as follows: Plan A was an anatomical IMRT or VMAT plan based on the total lung; Plan F was a functional IMRT or VMAT plan based on the functional lung. Dosimetric parameters (percentage of total lung volume irradiated with ≥20 Gy [V20], and mean dose of total lung [MLD]) of the two plans were compared. Results: V20 was lower in Plan F than in Plan A (mean 1.5%, p = 0.025 in IMRT, mean 1.6%, p = 0.044 in VMAT) achieved by a reduction in MLD (mean 0.23 Gy, p = 0.083 in IMRT, mean 0.5 Gy, p = 0.042 in VMAT). No differences were noted in target volume coverage and organ-at-risk doses. Conclusions: Functional IGRT planning based on LAA in respiratory-guided IMRT or VMAT appears to be effective in preserving a functional lung in lung cancer patients with COPD.

  9. Intensity modulated radiotherapy in early stage Hodgkin lymphoma patients: Is it better than three dimensional conformal radiotherapy?

    OpenAIRE

    De Sanctis Vitaliana; Bolzan Chiara; D’Arienzo Marco; Bracci Stefano; Fanelli Alessandro; Cox Maria; Valeriani Maurizio; Osti Mattia F; Minniti Giuseppe; Chiacchiararelli Laura; Enrici Riccardo

    2012-01-01

    Abstract Background Cure rate of early Hodgkin Lymphoma are high and avoidance of late toxicities is of paramount importance. This comparative study aims to assess the normal tissue sparing capability of intensity-modulated radiation therapy (IMRT) versus standard three-dimensional conformal radiotherapy (3D-CRT) in terms of dose-volume parameters and normal tissue complication probability (NTCP) for different organs at risk in supradiaphragmatic Hodgkin Lymphoma (HL) patients. Methods Ten HL...

  10. Decommissioning of Radiotherapy Facilities

    International Nuclear Information System (INIS)

    Radiotherapy units containing high activity sealed radioactive sources of 60Co or 137Cs are mainly use for medical, research or calibration applications. After several half-lives of decay, the radionuclide source has to be changed or the unit is decommissioned if no longer required. Before starting a decommissioning project it is very important to look for documents relating to any sources held or installed in equipment. In general this should be no problem because the recommended working life of such sealed radioactive sources is limited to 10 or a maximum of 15 years. These time periods are short in comparison with other facilities like research laboratories or small reactors. These documents (source certificates) will be very helpful to plan the decommissioning because they say everything about the original activity of the source at a reference date, the type of the source and the manufacturer. The next step may be to contact the machine supplier or the source manufacturer, but be aware that neither may still be in existence or may have changed their type of business. In such cases, it is recommended to contact national or international sealed source manufacturers or suppliers for help. Sometimes it is also helpful to contact colleagues in other hospitals or research centres to ask for information about specialists in this topic. In general it is not useful, and even very dangerous, to try to decommission such a unit without expert help It is essential to have specialist tools and shielded containers to recover the source out of the unit. It is strongly recommended to invite the source removal specialist for a site visit to review the situation before starting any decommissioning process. A further problem can occur, if the source must be transported to a national storage centre or even an international storage facility, as the source must be packaged to meet international transport requirements. The end state of such a project should be an empty room where the

  11. Impact of Radiotherapy Treatment on Jordanian Cancer Patients’ Quality of Life and Fatigue

    Directory of Open Access Journals (Sweden)

    Kholoud Abu Obead

    2013-11-01

    Full Text Available Background: The distressing treatment of cancer whether chemotherapy or radiotherapy is associated with fatigue and has negative impact on patient quality of life (QOL. Objectives: The purposes of this study were to examine the impact of radiotherapy treatment on Jordanian cancer patients’ QOL and fatigue, and to explore the relationship between fatigue and QOL. Methods: One group quasi-experimental correlational design was used with 82 patients who had been diagnosed with cancer and required radiotherapy treatment. QOL was measured using the Functional Assessment of Cancer Therapy-General (FACT-G. Fatigue was measured using Piper Fatigue Scale (PFS. Data were collected over a period of three months, and analyzed using Pearson Product Moment Correlation, descriptive statistics and paired-sample t-test. Results: Significant differences were found between pre- and post- radiotherapy QOL mean total scores (t=19.3, df=79, P<0.05, as well as physical, emotional, sexual, and functional wellbeing dimensions. Statistically significant differences were found between pre- and post- radiotherapy fatigue mean total scores (t=-8.95, df=79, P<0.05, as well as on behavioral, affective, sensory, and cognitive dimensions of PFS. Quality of life total scores correlated significantly and negatively with total fatigue scores (P<0.01. Conclusions: Exposure of cancer patient to radiotherapy treatment increased their fatigue level and decreased their QOL.  Nurses should assess cancer patients before, during, and after their treatment to design proper interventions to reduce fatigue and enhance QOL.

  12. Proton Radiotherapy for Pediatric Sarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Ladra, Matthew M.; Yock, Torunn I., E-mail: tyock@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114 (United States)

    2014-01-14

    Pediatric sarcomas represent a distinct group of pathologies, with approximately 900 new cases per year in the United States alone. Radiotherapy plays an integral role in the local control of these tumors, which often arise adjacent to critical structures and growing organs. The physical properties of proton beam radiotherapy provide a distinct advantage over standard photon radiation by eliminating excess dose deposited beyond the target volume, thereby reducing both the dose of radiation delivered to non-target structures as well as the total radiation dose delivered to a patient. Dosimetric studies comparing proton plans to IMRT and 3D conformal radiation have demonstrated the superiority of protons in numerous pediatric malignancies and data on long-term clinical outcomes and toxicity is emerging. In this article, we review the existing clinical and dosimetric data regarding the use of proton beam radiation in malignant bone and soft tissue sarcomas.

  13. Radiotherapy in osseous metastasizing carcinoid

    International Nuclear Information System (INIS)

    In an 51-year old patient with a disseminately metastasizing bronchus carcinoid, percutaneous radiotherapy was employed as a palliative measure against most severe pain in the region of bone metastases. In all irradiated regions (entire vertebral column and both shoulders) good pain relief was achieved in 2 weeks, lasting until the end of the follow-up period (18 months after irradiation), by application of 30 Gy photon radiation. Correlated with the subjective pain relief was a reduction of the required quantity of analgesics, a reduction of the greatly increased activity of alkaline phosphatase in the serum, and roentgenological sclerosing of the metastatic bone lesions. This case report is intended to point to the possibility of employing radiotherapy in similar cases where medication has finally proved futile, since the rare reports in literature are mostly negative. (orig.)

  14. Analysis of the Effect of the Application of Four-dimensional Color Doppler Ultrasound in Prenatal Screening of Fetal Malformation%产前胎儿畸形筛查中四维彩超的应用效果分析

    Institute of Scientific and Technical Information of China (English)

    纪亚梅; 王文俊

    2016-01-01

    目的:探讨产前胎儿畸形筛查中四维彩超的应用效果。方法方便选取2013年1月—2016年2月在该院进行产前筛查的2200例中晚期孕妇作为研究对象,分别对其进行二维彩超及四维彩超检查,根据胎儿出生后情况或引产结果对二维彩超及四维彩超的检出率进行比较。结果二维彩超对胎儿畸形的检出率为76.92%(40/52),四维彩超对胎儿畸形的检出率为96.15%(50/52),四维彩超对胎儿畸形的检出率明显高于二维彩超(P﹤0.01)。结论与二维彩超相比,四维彩超在胎儿畸形检出方面具有明显优势,值得临床推广应用。%Objective To investigate the application effect of four dimensional color Doppler ultrasound in prenatal screen-ing of fetal malformation. Methods 2 200 cases of advanced pregnant women from January 2013 to February 2016 in our hospital were selected as research subjects. Two dimensional color Doppler ultrasound and four-dimensional color Doppler ultrasound examination were carried out on them. According to the results of the fetus after birth or induction of labor, the detection rate of two-dimensional color Doppler ultrasound and four-dimensional color Doppler ultrasound were compared. Results The detection rate of two-dimensional color Doppler ultrasound for fetal malformation was 76.92%(40/52), while that of four-dimensional color Doppler ultrasound was 96.15%(50/52). Thus the detection rate of four-dimensional color Doppler ultrasound was obviously higher than that of two-dimensional color Doppler ultrasound(P﹤0.01). Conclusion Com-pared with two-dimensional ultrasound, four-dimensional color Doppler ultrasound in the detection of fetal abnormalities has obvious advantages, which is worth clinical application.

  15. Comparison of patient-reported late treatment toxicity (LENT-SOMA) with quality of life (EORTC QLQ-C30 and QLQ-H and N35) assessment after head and neck radiotherapy

    International Nuclear Information System (INIS)

    Purpose: The patient's role in toxicity reporting is increasingly acknowledged but requires the adaptation and validation of toxicity reporting instruments for patient use as most toxicity scales are designed for physician use. Recording of radiotherapy related late toxicity is important and needs to be improved. A patient-scored symptom questionnaire of late treatment effects using LENT-SOMA was compared with a recognised quality of life tool (EORTC QLQ-C30/H and N35). Materials/methods: LENT-SOMA and EORTC QLQ-C30 patient questionnaires were prospectively completed by 220 head and neck cancer patients over 3 years and 72 completed EORTC QLQ-H and N35 questionnaires at 2 years post-radiotherapy. Results: Endpoints common to both questionnaires (pain, swallowing, dental pain, dry mouth, opening mouth, analgesics) were matched. Spearman rank correlation coefficients with ρ > 0.6 (P < 0.001) were obtained for all 'matched' scales except for analgesics scale, ρ = 0.267 (P < 0.05). There was good agreement between LENT-SOMA and EORTC QLQ-H and N35 except for analgesic endpoints. Global quality of life scores correlated negatively with average LENT-SOMA scores (P < 0.001). Significant differences in average LENT-SOMA scores between treatment modalities were found. The LENT-SOMA questionnaire has demonstrated a high Cronbach's α value (0.786) indicating good reliability. Conclusions: LENT-SOMA patient questionnaire results agreed well with those from the EORTC QLQ-H and N35 questionnaire for toxicity items where they could be compared explicitly, particularly for subjective endpoints. Patient-reported late toxicity had a negative impact on quality of life. The LENT-SOMA patient questionnaire is both reliable and sensitive to differences between patients treated with different modalities. A patient-based questionnaire is an important contributor to capturing late radiotherapy effects.

  16. Experiment on radiotherapy of postnatal mastitis

    International Nuclear Information System (INIS)

    The results of radiotherapy of postnatal mastitis in 78 women are presented. It is shown that the radiotherapy is the method of choice. Application of radiotherapy at different stages of disease promotes either complete resolution of infiltration (1-2 irradiations) or stipulates the decrease in temperature, abatement of pains and improvement of general state (at the presence of purulent fusion of mammary tissue). X-ray therapy of postnatal mastitis has does not affect the lactational function of mammary gland

  17. Risk-adapted targeted intraoperative radiotherapy versus whole-breast radiotherapy for breast cancer

    DEFF Research Database (Denmark)

    Vaidya, Jayant S; Wenz, Frederik; Bulsara, Max;

    2014-01-01

    The TARGIT-A trial compared risk-adapted radiotherapy using single-dose targeted intraoperative radiotherapy (TARGIT) versus fractionated external beam radiotherapy (EBRT) for breast cancer. We report 5-year results for local recurrence and the first analysis of overall survival....

  18. Single fraction radiotherapy versus multiple fraction radiotherapy for bone metastases in prostate cancer patients: comparative effectiveness

    International Nuclear Information System (INIS)

    External beam radiotherapy (EBRT) is an effective treatment for symptomatic bone metastases from a variety of primary malignancies. Previous meta-analyses and systematic reviews have reported on the efficacy of EBRT on bone metastases from multiple primaries. This review is focused on the comparative effectiveness of single fraction radiotherapy versus multiple fraction radiotherapy for bone metastases in prostate cancer patients

  19. Clinical Usefulness of Implanted Fiducial Markers for Hypofractionated Radiotherapy of Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Min; Ahn, Sung Hwan; Lee, Hyung Hwan; Lee, Hyung Sik; Hur, Woo Joo; Yoon, Jin Han; Kim, Tae Hyo; Kim, Soo Dong; Yun, Seong Guk [Dong-A University School of Medicine, Busan (Korea, Republic of)

    2011-06-15

    To assess the usefulness of implanted fiducial markers in the setup of hypofractionated radiotherapy for prostate cancer patients by comparing a fiducial marker matched setup with a pelvic bone match. Four prostate cancer patients treated with definitive hypofractionated radiotherapy between September 2009 and August 2010 were enrolled in this study. Three gold fiducial markers were implanted into the prostate and through the rectum under ultrasound guidance around a week before radiotherapy. Glycerin enemas were given prior to each radiotherapy planning CT and every radiotherapy session. Hypofractionated radiotherapy was planned for a total dose of 59.5 Gy in daily 3.5 Gy with using the Novalis system. Orthogonal kV X-rays were taken before radiotherapy. Treatment positions were adjusted according to the results from the fusion of the fiducial markers on digitally reconstructed radiographs of a radiotherapy plan with those on orthogonal kV X-rays. When the difference in the coordinates from the fiducial marker fusion was less than 1 mm, the patient position was approved for radiotherapy. A virtual bone matching was carried out at the fiducial marker matched position, and then a setup difference between the fiducial marker matching and bone matching was evaluated. Three patients received a planned 17-fractionated radiotherapy and the rest underwent 16 fractionations. The setup error of the fiducial marker matching was 0.94{+-}0.62 mm (range, 0.09 to 3.01 mm; median, 0.81 mm), and the means of the lateral, craniocaudal, and anteroposterior errors were 0.39{+-}0.34 mm, 0.46{+-}0.34 mm, and 0.57{+-}0.59 mm, respectively. The setup error of the pelvic bony matching was 3.15{+-}2.03 mm (range, 0.25 to 8.23 mm; median, 2.95 mm), and the error of craniocaudal direction (2.29{+-}1.95 mm) was significantly larger than those of anteroposterior (1.73{+-}1.31 mm) and lateral directions (0.45{+-}0.37 mm), respectively (p< 0.05). Incidences of over 3 mm and 5 mm in setup

  20. Immediate side effects of large fraction radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Devereux, S.; Hatton, M.Q.F.; Macbeth, F.R. [Glasgow Western Infirmary (United Kingdom)

    1997-09-01

    The use of hypofractionated radiotherapy regiments is becoming more widely recognized in the palliation of non-small cell lung carcinoma (NSCLC). Anecdoctal reports of chest pain, rigors and fevers in the hours that follow radiotherapy led us to perform a survey estimating the frequency and severity of these symptoms following treatment to the thorax. We conclude that patients receiving palliative radiotherapy for bronchial carcinoma often develop significant symptoms in the hours following treatment. The timing and duration suggest a relationship with the radiotherapy, and we feel that patients should be warned of the possible occurrence of these symptoms. (author).

  1. Targeting IAP proteins in combination with radiotherapy

    International Nuclear Information System (INIS)

    The efficacy of radiotherapy critically depends on the activation of intrinsic cell death programs in cancer cells. This implies that evasion of cell death, a hallmark of human cancers, can contribute to radioresistance. Therefore, novel strategies to reactivate cell death programs in cancer cells are required in order to overcome resistance to radiotherapy. Since Inhibitor of Apoptosis (IAP) proteins are expressed at high levels in multiple cancers and block cell death induction at a central point, therapeutic targeting of IAP proteins represents a promising approach to potentiate the efficacy of radiotherapy. The current review discusses the concept of targeting IAP proteins in combination with radiotherapy

  2. Research on four-dimensional data assimilation applied in a Meiyu front rainstorm case%四维数据同化在一次梅雨锋暴雨过程中的应用研究

    Institute of Scientific and Technical Information of China (English)

    何斌; 徐瑞国; 牛萍

    2012-01-01

    This paper mainly applied four-dimensional observation nudging assimilation in WRF model to a rainstorm case in the Meiyu season of 2008 and studied the impact of different assimilation strategies on the simulation results. The assimilation data include 12 h rawinsonde observations and 3 h surface observations. The results show that the assimilation of rawinsonde observations can correct the displacement and development of meso-α system, therefore, effectively improve the location of the heavy rain band. Oppositely, the assimilation of moisture observations underestimates the intensity of the heavy rain band, because reducing water vapor mixing ratio in the near moist saturation regions results in decreasing latent heat and weakening the intensity of convection and precipitation in these regions. The assimilation of the surface observations can improve planetary boundary layer in the model. Usually this kind of effect is evident in the model surface layer and tends to decreases with increasing height upward. The simulation quality of the PBL is very important to model precipitation, so that the inclusion of surface observations makes model precipitation more real. Regional grid-nested simulation tests indicate that the data assimilation on coarse grid can effectively restrain the error growth of meso-α system and the one on fine grid can further reduce the error growth of meso-β system.%通过2008年梅雨季内的一次暴雨过程来着重研究WRF模式中四维测站同化技术的应用情况以及不同的同化策略对模拟结果的影响,使用的同化资料包括常规高空和地面探测资料.结果表明:高空探测资料的同化能够较好地修正中α尺度系统的移动发展速度,从而有效地改进强降雨带的落区位置;湿度观测资料的同化反而降低了强降雨带的降水强度,这可能因为同化湿度观测量可能减小近饱和区域内的水汽混合比,从而导致这些区域内的潜热加热减小,对

  3. 利用微破裂四维影像技术分析二次加砂压裂效果%Effect Analysis of Secondary Sand Fracturing Using Four-Dimensional Seismic Imaging of Micro-Fractures

    Institute of Scientific and Technical Information of China (English)

    安丰军; 赵安军; 周慧智; 段贵府

    2013-01-01

    在水力加砂压裂中,目前常用获取压裂裂缝几何形态和几何参数信息的手段(如井温测井、阵列声波测井)存在不足,为此,试验应用了微破裂向量扫描四维影像监测技术。该技术通过在近地表按不同排列形式布置多道地震采集站形成的微地震仪器阵列,共同接收地下储层液体流动压力引起的岩石微破裂所产生的纵波和横波,检波器接收到信号后通过能量转换器将振动波转换成电信号,经前置放大后以电磁波的形式,发射送入记录、分析系统,利用多波三分量地震数据进行矢量叠加、振幅反演计算、四维相关可视化裂缝形态解释技术,在时间域上分析裂缝的演变过程。在二连盆地兰地1井的现场试验表明,该技术可以进行压裂施工全过程破裂能量分析、裂缝产生演变过程分析及裂缝空间形态参数求取,能真实反映二次加砂压裂效果并为下一步的压裂施工设计提供可靠依据。%Commonly used means to obtain fracture geometry at present such as temperature log and arrayed acoustic log have some deficiencies ,four-dimensional vector scanning imaging was tested .During hydraulic fractu-ring ,longitudinal wave and shear wave produced from rock failure are received by micro-seismic instrument array of multi-channel seismic acquisition station in different patterns near the surface .Wave signals received by geophones are then converted into electrical signals through energy converter .After pre-amplification ,they are sent to the re-cording and analysis system in the form of electromagnetic waves .Finally vector stacking of multi-wave three com-ponent seismic data ,amplitude inversion modeling and four dimension related visual fracture morphology interpreta-tion techniques are used to analyze the evolution of fractures in time domain .Its application in Well Landi 1 of Er-lian Basin showed it could be used to analyze the

  4. Radiotherapy for pituitary adenoma: long-term outcome and sequelae

    International Nuclear Information System (INIS)

    Purpose/Objective: To review outcome and treatment sequelae in patients treated with external-beam radiotherapy for pituitary adenomas. Materials and Methods: One hundred forty-one patients with pituitary adenomas received radiotherapy and had 2-year minimum follow-up. One hundred twenty-one patients had newly diagnosed adenomas and 20 patients had recurrent tumors. Newly diagnosed tumors were treated with surgery and radiotherapy (S + RT; n=98) or radiotherapy alone (RT; n=23). Patients with recurrent tumors received salvage treatment with S+RT (n=10) or RT (n=10). The impact of age, sex, presenting symptoms, tumor extent, surgery type, degree of resection, hormonal activity, primary or salvage therapy, and radiotherapy dose on local control and cause-specific survival was analyzed. Effect of therapy on vision, hormonal function, life satisfaction, neurocognitive function, and affective symptoms was examined. A Likert scale survey was used for assessment of life satisfaction, neurocognitive status, and affective symptoms after therapy. Survey results from the RT patients were compared to a control group treated with transsphenoidal surgery alone (S). Survival analysis employed the Kaplan-Meier method. Multivariate analysis used the forward step-wise sequence of chi-squares for the log-rank test. Results: At 10 years, local control for the S+RT group (S + RT) was 95% and not statistically different (p=.58) than for patients in the RT group (90%). Cause-specific survival rates were also similar (p=.88) between the S+RT (97%) and RT (99%) groups. Patients with prolactin- and ACTH-secreting tumors had significantly worse local control, as did patients treated for recurrent tumors. Cause-specific survival was not decreased in any patient group. Multivariate analysis for local control and cause-specific survival revealed only young age to be predictive of worse outcome (p=.0354 and p=.0355 respectively). Visual function was either unaffected or improved in most patients

  5. Targeted Radiotherapy of Estrogen Receptor Positive Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Raghavan Rajagopalan

    2006-08-31

    The overall objectives of the proposal were to develop estrogen receptor (ER) binding small molecule radiopharmaceuticals for targeted radiotherapy of ER positive (ER+) tumors. In particular, this proposal focused on embedding a {sup 186,188}Re or a {sup 32}P radionuclide into an estrogen steroidal framework by isosteric substitution such that the resulting structure is topologically similar to the estrogen (estrogen mimic). The estrogen mimic molecules expected to bind to the ER and exhibit biodistribution akin to that of native estrogen due to structural mimicry. It is anticipated that the {sup 186,188}Re- or a {sup 32}P-containing estrogen mimics will be useful for targeted molecular radiotherapy of ER+ tumors. It is well established that the in vivo target tissue uptake of estrogen like steroidal molecules is related to the binding of the steroids to sex hormone binding globulin (SHBG). SHBG is important in the uptake of estrogens and testosterone in target tissues by SHBG receptors on the cell surface. However, hitherto the design of estrogen like small molecule radiopharmaceuticals was focused on optimizing ER binding characteristics without emphasis on SHBG binding properties. Consequently, even the molecules with good ER affinity in vitro, performed poorly in biodistribution studies. Based on molecular modeling studies the proposal focused on developing estrogen mimics 1-3 which were topologically similar to native estrogens, and form hydrogen bonds in ER and SHBG in the same manner as those of native estrogens. To this end the technical objectives of the proposal focused on synthesizing the rhenium-estrone and estradiol mimics 1 and 2 respectively, and phosphorous estradiol mimic 3 and to assess their stability and in vitro binding characteristics to ER and SHBG.

  6. Embracing service user involvement in radiotherapy education: A discussion paper

    International Nuclear Information System (INIS)

    Aim: There is currently a drive within cancer services to incorporate user involvement in delivery and education, as such the aim of this article is to investigate the potential role of service users in pre-registration education and how this could impact on radiotherapy programmes. Method: Key databases were searched for terms: patient participation, service user involvement, health care education, student assessment, patient involvement, pre-registration education and training. Suitable literature was reviewed and references within all articles and documents were investigated to ensure as broad and an inclusive search possible. Results: There is little published literature indicating user involvement in radiotherapy education but many studies in nursing, medicine and other allied health professions indicate a rationale for user involvement. Discussion: There are benefits of involving service users, i.e. gaining insight from patients and carers perspectives, challenges stereotypes and assumptions. Disadvantages include the quality of the feedback from users in assessment, resources required, and the ethical considerations. Conclusion: Inclusion of service users in radiotherapy education is recommended in line with cancer care policy, they provide a unique perspective to learning and involvement should be encouraged

  7. Radiotherapy Facilities: Master Planning and Concept Design Considerations (Russian Edition)

    International Nuclear Information System (INIS)

    This publication provides guidelines on how to plan a radiotherapy facility in terms of the strategic master planning process including the legal, technical and infrastructure requirements. It outlines a risk assessment methodology and a typical project work plan, and describes the professional expertise required for the implementation of such a project. Generic templates for a block design are suggested, which include possibilities for future expansion. These templates can be overlaid onto the designated site such that the most efficient workflow between the main functional areas can be ensured. A sample checklist is attached to act as a guideline for project management and to indicate the critical stages in the process where technical expert assistance may be needed. The publication is aimed at professionals and administrators involved in infrastructure development, planning and facility management, as well as engineers, building contractors and radiotherapy professionals

  8. Treatment outcome in patients with vulvar cancer: comparison of concurrent radiotherapy to postoperative radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ja Young; Kim, Sung Hwan; Kim, Ki Won; Park, Dong Choon; Yoon, Joo Hee; Yoon, Sei Chul [St. Vincent' s Hospital, The Catholic University of Korea School of Medicine, Seoul (Korea, Republic of); Yu, Mina [St. Mary' s Hospital, The Catholic University of Korea School of Medicine, Seoul (Korea, Republic of)

    2012-03-15

    To evaluate outcome and morbidity in patients with vulvar cancer treated with radiotherapy, concurrent chemoradiotherapy or postoperative radiotherapy. The records of 24 patients treated with radiotherapy for vulvar cancer between July 1993 and September 2009 were retrospectively reviewed. All patients received once daily 1.8-4 Gy fractions external beam radiotherapy to median 51.2 Gy (range, 19.8 to 81.6 Gy) on pelvis and inguinal nodes. Seven patients were treated with primary concurrent chemoradiotherapy, one patient was treated with primary radiotherapy alone, four patients received palliative radiotherapy, and twelve patients were treated with postoperative radiotherapy. Twenty patients were eligible for response evaluation. Response rate was 55% (11/20). The 5-year disease free survival was 42.2% and 5-year overall survival was 46.2%, respectively. Fifty percent (12/24) experienced with acute skin complications of grade III or more during radiotherapy. Late complications were found in 8 patients. 50% (6/12) of patients treated with lymph node dissection experienced severe late complications. One patient died of sepsis from lymphedema. However, only 16.6% (2/12) of patients treated with primary radiotherapy developed late complications. Outcome of patients with vulvar cancer treated with radiotherapy showed relatively good local control and low recurrence. Severe late toxicities remained higher in patients treated with both node dissection and radiotherapy.

  9. Radiotherapy and Brachytherapy : Proceedings of the NATO Advanced Study Institute on Physics of Modern Radiotherapy & Brachytherapy

    CERN Document Server

    Lemoigne, Yves

    2009-01-01

    This volume collects a series of lectures presented at the tenth ESI School held at Archamps (FR) in November 2007 and dedicated to radiotherapy and brachytherapy. The lectures focus on the multiple facets of radiotherapy in general, including external radiotherapy (often called teletherapy) as well as internal radiotherapy (called brachytherapy). Radiotherapy strategy and dose management as well as the decisive role of digital imaging in the associated clinical practice are developed in several articles. Grouped under the discipline of Conformal Radiotherapy (CRT), numerous modern techniques, from Multi-Leaf Collimators (MLC) to Intensity Modulated RadioTherapy (IMRT), are explained in detail. The importance of treatment planning based upon patient data from digital imaging (Computed Tomography) is also underlined. Finally, despite the quasi- totality of patients being presently treated with gamma and X-rays, novel powerful tools are emerging using proton and light ions (like carbon ions) beams, bound to bec...

  10. Regression and local control rates after radiotherapy for jugulotympanic paragangliomas: Systematic review and meta-analysis

    International Nuclear Information System (INIS)

    The primary treatment goal of radiotherapy for paragangliomas of the head and neck region (HNPGLs) is local control of the tumor, i.e. stabilization of tumor volume. Interestingly, regression of tumor volume has also been reported. Up to the present, no meta-analysis has been performed giving an overview of regression rates after radiotherapy in HNPGLs. The main objective was to perform a systematic review and meta-analysis to assess regression of tumor volume in HNPGL-patients after radiotherapy. A second outcome was local tumor control. Design of the study is systematic review and meta-analysis. PubMed, EMBASE, Web of Science, COCHRANE and Academic Search Premier and references of key articles were searched in March 2012 to identify potentially relevant studies. Considering the indolent course of HNPGLs, only studies with ⩾12 months follow-up were eligible. Main outcomes were the pooled proportions of regression and local control after radiotherapy as initial, combined (i.e. directly post-operatively or post-embolization) or salvage treatment (i.e. after initial treatment has failed) for HNPGLs. A meta-analysis was performed with an exact likelihood approach using a logistic regression with a random effect at the study level. Pooled proportions with 95% confidence intervals (CI) were reported. Fifteen studies were included, concerning a total of 283 jugulotympanic HNPGLs in 276 patients. Pooled regression proportions for initial, combined and salvage treatment were respectively 21%, 33% and 52% in radiosurgery studies and 4%, 0% and 64% in external beam radiotherapy studies. Pooled local control proportions for radiotherapy as initial, combined and salvage treatment ranged from 79% to 100%. Radiotherapy for jugulotympanic paragangliomas results in excellent local tumor control and therefore is a valuable treatment for these types of tumors. The effects of radiotherapy on regression of tumor volume remain ambiguous, although the data suggest that regression can

  11. 肺癌放疗患者CT灌注值变化及其在预后评估中的作用%Clinical value of perfusion CT scan in the assessment of prognosis of lung cancer patients treated with radio-therapy

    Institute of Scientific and Technical Information of China (English)

    李玉

    2015-01-01

    目的:分析CT灌注值的变化对于肺癌患者放疗后的治疗效果以及预后的评估效果。方法选取在我院进行住院治疗的肺癌患者62例,根据治疗效果分为有效及无效组,对治疗有效组以及治疗无效组放疗后CT灌注值变化、生存期、CT灌注值与生存期的相关性以及表面通透性不同变化对于生存期的影响进行观察。结果治疗有效组的肿瘤组织血流量、肿瘤组织血容量以及表面通透性均显著低于治疗无效组(P<0.05);肿瘤组织血流量、肿瘤组织血容量以及表面通透性与生存期均显著相关,表面通透性的相关程度最高(P<0.05);表面通透性降低的生存期要显著高于表面通透性降低患者的生存期(P<0.05)。结论 CT灌注成像参数可以作为放疗后的疗效以及预后的指标。%Objective To analyze the clinical value of perfusion CT scan in the assessment of prognosis of lung cancer patients treated with radiotherapy. Methods 62 lung cancer patients were divided into two groups based on curative effect. The change of CT perfusion value and the correlation among survival time and CT perfusion value were observed. Results The blood flow of tumor tissue, blood volume of tumor tissue and permeability surface of vessels after radiotherapy were obviously lower in the valid group than in the invalid group ( P<0. 05 ) . The blood flow of tumor tissue, blood volume of tumor tissue and permeability surface of vessels had relationship with the surviv-al time, and permeability surface of the vessels was highly correlated with survival time (P<0. 05). Conclusion CT perfusion parameters can assess the effect of radiotherapy and prediction of prognosis of patients with lung cancer.

  12. Radiotherapy versus combined modality in early stages

    DEFF Research Database (Denmark)

    Specht, L; Carde, P; Mauch, P;

    1992-01-01

    In early stage Hodgkin's disease the optimal choice of treatment for the individual patient is still an unresolved issue. So far, twenty-two randomized trials of radiotherapy alone versus radiotherapy plus combination chemotherapy have been carried out worldwide. The preliminary results of a glob...

  13. Radiological protection of the radiotherapy patient?

    International Nuclear Information System (INIS)

    We propose that the system and concepts of radiation protection should not be used with reference to radiotherapy patients. We justify this on conceptual grounds. The patient undergoing radiotherapy procedures, as prescribed by the medical practitioner, is protected by the quality assurance system legally required for medical exposures. (author)

  14. Standard-Fractionated Radiotherapy for Optic Nerve Sheath Meningioma: Visual Outcome Is Predicted by Mean Eye Dose

    International Nuclear Information System (INIS)

    Purpose: Radiotherapy has shown its efficacy in controlling optic nerve sheath meningiomas (ONSM) tumor growth while allowing visual acuity to improve or stabilize. However, radiation-induced toxicity may ultimately jeopardize the functional benefit. The purpose of this study was to identify predictive factors of poor visual outcome in patients receiving radiotherapy for ONSM. Methods and Materials: We conducted an extensive analysis of 10 patients with ONSM with regard to clinical, radiologic, and dosimetric aspects. All patients were treated with conformal radiotherapy and subsequently underwent biannual neuroophthalmologic and imaging assessments. Pretreatment and posttreatment values of visual acuity and visual field were compared with Wilcoxon’s signed rank test. Results: Visual acuity values significantly improved after radiotherapy. After a median follow-up time of 51 months, 6 patients had improved visual acuity, 4 patients had improved visual field, 1 patient was in stable condition, and 1 patient had deteriorated visual acuity and visual field. Tumor control rate was 100% at magnetic resonance imaging assessment. Visual acuity deterioration after radiotherapy was related to radiation-induced retinopathy in 2 patients and radiation-induced mature cataract in 1 patient. Study of radiotherapy parameters showed that the mean eye dose was significantly higher in those 3 patients who had deteriorated vision. Conclusions: Our study confirms that radiotherapy is efficient in treating ONSM. Long-term visual outcome may be compromised by radiation-induced side effects. Mean eye dose has to be considered as a limiting constraint in treatment planning.

  15. Credentialing of radiotherapy centres for a clinical trial of adaptive radiotherapy for bladder cancer (TROG 10.01)

    International Nuclear Information System (INIS)

    Background: Daily variations in bladder filling make conformal treatment of bladder cancer challenging. On-line adaptive radiotherapy with a choice of plans has been demonstrated to reduce small bowel irradiation in single institution trials. In order to support a multicentre feasibility clinical trial on adaptive radiotherapy for bladder cancer (TROG 10.01) a credentialing programme was developed for centres wishing to participate. Methods: The credentialing programme entails three components: a facility questionnaire; a planning exercise which tests the ability of centres to create three adaptive plans based on a planning and five cone beam CTs; and a site visit during which image quality, imaging dose and image guidance procedures are assessed. Image quality and decision making were tested using customised inserts for a Perspex phantom (Modus QUASAR) that mimic different bladder sizes. Dose was assessed in the same phantom using thermoluminescence dosimetry (TLD). Results: All 12 centres participating in the full credentialing programme were able to generate appropriate target volumes in the planning exercise and identify the correct target volume and position the bladder phantom in the phantom within 3 mm accuracy. None of the imaging doses exceeded the limit of 5 cGy with a CT on rails system having the lowest overall dose. Conclusion: A phantom mimicking the decision making process for adaptive radiotherapy was found to be well suited during site visits for credentialing of centres participating in a clinical trial of adaptive radiotherapy for bladder cancer. Combined with a planning exercise the site visit allowed testing the ability of centres to create adaptive treatment plans and make appropriate decisions based on the volumetric images acquired at treatment.

  16. Relationships between family physicians’ referral for palliative radiotherapy, knowledge of indications for radiotherapy, and prior training: a survey of rural and urban family physicians

    International Nuclear Information System (INIS)

    The primary objective of this research was to assess the relationship between FPs’ knowledge of palliative radiotherapy (RT) and referral for palliative RT. 1001 surveys were sent to FPs who work in urban, suburban, and rural practices. Respondents were tested on their knowledge of palliative radiotherapy effectiveness and asked to report their self-assessed knowledge. The response rate was 33%. FPs mean score testing their knowledge of palliative radiotherapy effectiveness was 68% (SD = 26%). The majority of FPs correctly identified that painful bone metastases (91%), airway obstruction (77%), painful local disease (85%), brain metastases (76%) and spinal cord compression (79%) can be effectively treated with RT, though few were aware that hemoptysis (42%) and hematuria (31%) can be effectively treated. There was a linear relationship between increasing involvement in palliative care and both self-assessed (p < 0.001) and tested (p = 0.02) knowledge. FPs had higher mean knowledge scores if they received post-MD training in palliative care (12% higher; p < 0.001) or radiotherapy (15% higher; p = 0.002). There was a strong relationship between FPs referral for palliative radiotherapy and both self-assessed knowledge (p < 0.001) and tested knowledge (p = 0.01). Self-assessed and tested knowledge of palliative RT is positively associated with referral for palliative RT. Since palliative RT is underutilized, further research is needed to assess whether family physician educational interventions improve palliative RT referrals. The current study suggests that studies could target family physicians already in practice, with educational interventions focusing on hemostatic and other less commonly known indications for palliative RT

  17. Successful radiotherapy of facial angiosarcoma.

    Science.gov (United States)

    Gkalpakiotis, S; Arenberger, P; Vohradnikova, O; Arenbergerova, M

    2008-11-01

    Cutaneous angiosarcoma of the face and scalp is a rare malignant vascular tumor that affects mostly Caucasian elderly males. At present, connections concerning the etiology of this neoplasm with radiation therapy, exposure to environmental carcinogens and chronic lymphedema have been described. Due to the difficult histologic evaluation, high local recurrence and tendency to early metastasing, angiosarcoma poses generally a very poor prognosis. We report the case of an 80-year-old patient who experienced successful removal of large, exophytic growing angiosarcoma of the face achieved with radiotherapy with long-term relapse-free survival. PMID:18986458

  18. Basic radiotherapy physics and biology

    CERN Document Server

    Chang, David S; Das, Indra J; Mendonca, Marc S; Dynlacht, Joseph R

    2014-01-01

    This book is a concise and well-illustrated review of the physics and biology of radiation therapy intended for radiation oncology residents, radiation therapists, dosimetrists, and physicists. It presents topics that are included on the Radiation Therapy Physics and Biology examinations and is designed with the intent of presenting information in an easily digestible format with maximum retention in mind. The inclusion of mnemonics, rules of thumb, and reader-friendly illustrations throughout the book help to make difficult concepts easier to grasp. Basic Radiotherapy Physics and Biology is a

  19. Quality and safety in radiotherapy

    CERN Document Server

    Pawlicki, Todd

    2010-01-01

    The first text to focus solely on quality and safety in radiotherapy, this work encompasses not only traditional, more technically oriented, quality assurance activities, but also general approaches of quality and safety. It includes contributions from experts both inside and outside the field to present a global view. The task of assuring quality is no longer viewed solely as a technical, equipment-dependent endeavor. Instead, it is now recognized as depending on both the processes and the people delivering the service. Divided into seven broad categories, the text covers: Quality Management

  20. Interfractional Positional Variability of Fiducial Markers and Primary Tumors in Locally Advanced Non-Small-Cell Lung Cancer During Audiovisual Biofeedback Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Nicholas O., E-mail: nroman@mcvh-vcu.edu [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA (United States); Shepherd, Wes [Department of Pulmonology, Virginia Commonwealth University, Richmond, VA (United States); Mukhopadhyay, Nitai [Department of Biostatistics, Virginia Commonwealth University, Richmond, VA (United States); Hugo, Geoffrey D.; Weiss, Elisabeth [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA (United States)

    2012-08-01

    Purpose: To evaluate implanted markers as a surrogate for tumor-based setup during image-guided lung cancer radiotherapy with audiovisual biofeedback. Methods and Materials: Seven patients with locally advanced non-small-cell lung cancer were implanted bronchoscopically with gold coils. Markers, tumor, and a reference bony structure (vertebra) were contoured for all 10 phases of the four-dimensional respiration-correlated fan-beam computed tomography and weekly four-dimensional cone-beam computed tomography. Results: The systematic/random interfractional marker-to-tumor centroid displacements were 2/3, 2/2, and 3/3 mm in the x (lateral), y (anterior-posterior), and z (superior-inferior) directions, respectively. The systematic/random interfractional marker-to-bone displacements were 2/3, 2/3, and 2/3 mm in the x, y, and z directions, respectively. The systematic/random tumor-to-bone displacements were 2/3, 2/4, and 4/4 mm in the x, y, and z directions, respectively. All displacements changed significantly over time (p < 0.0001). Conclusions: Although marker-based image guidance may decrease the risk for geometric miss compared with bony anatomy-based positioning, the observed displacements between markers and tumor centroids indicate the need for repeated soft tissue imaging, particularly in situations with large tumor volume change and large initial marker-to-tumor centroid distance.