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Sample records for respiratory gated hypofractionated

  1. MO-FG-BRA-05: Dosimetric and Radiobiological Validation of Respiratory Gating in Conventional and Hypofractionated Radiotherapy of the Lung: Effect of Dose, Dose Rate, Gating Window and Breathing Pattern

    Energy Technology Data Exchange (ETDEWEB)

    Cervino, L; Soultan, D; Pettersson, N; Yock, A; Cornell, M; Aguilera, J; Murphy, J; Advani, S; Moiseenko, V [University of California, San Diego, La Jolla, CA (United States); Gill, B [British Columbia Cancer Agency, Vancouver, BC (Canada)

    2016-06-15

    Purpose: to evaluate the dosimetric and radiobiological consequences from having different gating windows, dose rates, and breathing patterns in gated VMAT lung radiotherapy. Methods: A novel 3D-printed moving phantom with central high and peripheral low tracer uptake regions was 4D FDG-PET/CT-scanned using ideal, patient-specific regular, and irregular breathing patterns. A scan of the stationary phantom was obtained as a reference. Target volumes corresponding to different uptake regions were delineated. Simultaneous integrated boost (SIB) 6 MV VMAT plans were produced for conventional and hypofractionated radiotherapy, using 30–70 and 100% cycle gating scenarios. Prescribed doses were 200 cGy with SIB to 240 cGy to high uptake volume for conventional, and 800 with SIB to 900 cGy for hypofractionated plans. Dose rates of 600 MU/min (conventional and hypofractionated) and flattening filter free 1400 MU/min (hypofractionated) were used. Ion chamber measurements were performed to verify delivered doses. Vials with A549 cells placed in locations matching ion chamber measurements were irradiated using the same plans to measure clonogenic survival. Differences in survival for the different doses, dose rates, gating windows, and breathing patterns were analyzed. Results: Ion chamber measurements agreed within 3% of the planned dose, for all locations, breathing patterns and gating windows. Cell survival depended on dose alone, and not on gating window, breathing pattern, MU rate, or delivery time. The surviving fraction varied from approximately 40% at 2Gy to 1% for 9 Gy and was within statistical uncertainty relative to that observed for the stationary phantom. Conclusions: Use of gated VMAT in PET-driven SIB radiotherapy was validated using ion chamber measurements and cell survival assays for conventional and hypofractionated radiotherapy.

  2. Respiratory gating in cardiac PET

    DEFF Research Database (Denmark)

    Lassen, Martin Lyngby; Rasmussen, Thomas; Christensen, Thomas E

    2017-01-01

    BACKGROUND: Respiratory motion due to breathing during cardiac positron emission tomography (PET) results in spatial blurring and erroneous tracer quantification. Respiratory gating might represent a solution by dividing the PET coincidence dataset into smaller respiratory phase subsets. The aim...... of our study was to compare the resulting imaging quality by the use of a time-based respiratory gating system in two groups administered either adenosine or dipyridamole as the pharmacological stress agent. METHODS AND RESULTS: Forty-eight patients were randomized to adenosine or dipyridamole cardiac...... stress (82)RB-PET. Respiratory rates and depths were measured by a respiratory gating system in addition to registering actual respiratory rates. Patients undergoing adenosine stress showed a decrease in measured respiratory rate from initial to later scan phase measurements [12.4 (±5.7) vs 5.6 (±4...

  3. Evaluation of respiratory pattern during respiratory-gated radiotherapy

    International Nuclear Information System (INIS)

    Dobashi, Suguru; Mori, Shinichiro

    2014-01-01

    The respiratory cycle is not strictly regular, and generally varies in amplitude and period from one cycle to the next. We evaluated the characteristics of respiratory patterns acquired during respiratory gating treatment in more than 300 patients. A total 331 patients treated with respiratory-gated carbon-ion beam therapy were selected from a group of patients with thoracic and abdominal conditions. Respiratory data were acquired for a total of 3,171 fractions using an external respiratory sensing monitor and evaluated for respiratory cycle, duty cycle, magnitude of baseline drift, and intrafractional/interfractional peak inhalation/exhalation positional variation. Results for the treated anatomical sites and patient positioning were compared. Mean ± SD respiratory cycle averaged over all patients was 4.1 ± 1.3 s. Mean ± SD duty cycle averaged over all patients was 36.5 ± 7.3 %. Two types of baseline drift were seen, the first decremental and the second incremental. For respiratory peak variation, the mean intrafractional variation in peak-inhalation position relative to the amplitude in the first respiratory cycle (15.5 ± 9.3 %) was significantly larger than that in exhalation (7.5 ± 4.6 %). Interfractional variations in inhalation (17.2 ± 18.5 %) were also significantly greater than those in exhalation (9.4 ± 10.0 %). Statistically significant differences were observed between patients in the supine position and those in the prone position in mean respiratory cycle, duty cycle, and intra-/interfractional variations. We quantified the characteristics of the respiratory curve based on a large number of respiratory data obtained during treatment. These results might be useful in improving the accuracy of respiratory-gated treatment.

  4. Quality verification for respiratory gated proton therapy

    International Nuclear Information System (INIS)

    Kim, Eun Sook; Jang, Yo Jong; Park, Ji Yeon; Kang, Dong Yun; Yeom, Doo Seok

    2013-01-01

    To verify accuracy of respiratory gated proton therapy by measuring and analyzing proton beam delivered when respiratory gated proton therapy is being performed in our institute. The plan data of 3 patients who took respiratory gated proton therapy were used to deliver proton beam from proton therapy system. The manufactured moving phantom was used to apply respiratory gating system to reproduce proton beam which was partially irradiated. The key characteristics of proton beam, range, spreat-out Bragg peak (SOBP) and output factor were measured 5 times and the same categories were measured in the continuous proton beam which was not performed with respiratory gating system. Multi-layer ionization chamber was used to measure range and SOBP, and Scanditronix Wellhofer and farmer chamber was used to measure output factor. The average ranges of 3 patients (A, B, C), who had taken respiratory gated proton therapy or not, were (A) 7.226, 7.230, (B) 12.216, 12.220 and (C) 19.918, 19.920 g/cm 2 and average SOBP were (A) 4.950, 4.940, (B) 6.496, 6.512 and (C) 8.486, 8.490 g/cm 2 . And average output factor were (A) 0.985, 0.984 (B) 1.026, 1.027 and (C) 1.138, 1.136 cGy/MU. The differences of average range were -0.004, -0.004, -0.002 g/cm 2 , that of SOBP were 0.010, -0.016, -0.004 g/cm 2 and that of output factor were 0.001, -0.001, 0.002 cGy/MU. It is observed that the range, SOBP and output factor of proton beam delivered when respiratory gated proton therapy is being performed have the same beam quality with no significant difference compared to the proton beam which was continuously irradiated. Therefore, this study verified the quality of proton beam delivered when respiratory gated proton therapy and confirmed the accuracy of proton therapy using this

  5. Patient training in respiratory-gated radiotherapy

    International Nuclear Information System (INIS)

    Kini, Vijay R.; Vedam, Subrahmanya S.; Keall, Paul J.; Patil, Sumukh; Chen, Clayton; Mohan, Radhe

    2003-01-01

    Respiratory gating is used to counter the effects of organ motion during radiotherapy for chest tumors. The effects of variations in patient breathing patterns during a single treatment and from day to day are unknown. We evaluated the feasibility of using patient training tools and their effect on the breathing cycle regularity and reproducibility during respiratory-gated radiotherapy. To monitor respiratory patterns, we used a component of a commercially available respiratory-gated radiotherapy system (Real Time Position Management (RPM) System, Varian Oncology Systems, Palo Alto, CA 94304). This passive marker video tracking system consists of reflective markers placed on the patient's chest or abdomen, which are detected by a wall-mounted video camera. Software installed on a PC interfaced to this camera detects the marker motion digitally and records it. The marker position as a function of time serves as the motion signal that may be used to trigger imaging or treatment. The training tools used were audio prompting and visual feedback, with free breathing as a control. The audio prompting method used instructions to 'breathe in' or 'breathe out' at periodic intervals deduced from patients' own breathing patterns. In the visual feedback method, patients were shown a real-time trace of their abdominal wall motion due to breathing. Using this, they were asked to maintain a constant amplitude of motion. Motion traces of the abdominal wall were recorded for each patient for various maneuvers. Free breathing showed a variable amplitude and frequency. Audio prompting resulted in a reproducible frequency; however, the variability and the magnitude of amplitude increased. Visual feedback gave a better control over the amplitude but showed minor variations in frequency. We concluded that training improves the reproducibility of amplitude and frequency of patient breathing cycles. This may increase the accuracy of respiratory-gated radiation therapy

  6. Respiratory gating and multi field technique radiotherapy for esophageal cancer

    International Nuclear Information System (INIS)

    Ohta, Atsushi; Kaidu, Motoki; Tanabe, Satoshi

    2017-01-01

    To investigate the effects of a respiratory gating and multi field technique on the dose-volume histogram (DVH) in radiotherapy for esophageal cancer. Twenty patients who underwent four-dimensional computed tomography for esophageal cancer were included. We retrospectively created the four treatment plans for each patient, with or without the respiratory gating and multi field technique: No gating-2-field, No gating-4-field, Gating-2-field, and Gating-4-field plans. We compared the DVH parameters of the lung and heart in the No gating-2-field plan with the other three plans.Result In the comparison of the parameters in the No gating-2-field plan, there are significant differences in the Lung V 5Gy , V 20Gy , mean dose with all three plans and the Heart V 25Gy -V 40Gy with Gating-2-field plan, V 35Gy , V 40Gy , mean dose with No Gating-4-field plan and V 30Gy -V 40Gy , and mean dose with Gating-4-field plan. The lung parameters were smaller in the Gating-2-field plan and larger in the No gating-4-field and Gating-4-field plans. The heart parameters were all larger in the No gating-2-field plan. The lung parameters were reduced by the respiratory gating technique and increased by the multi field technique. The heart parameters were reduced by both techniques. It is important to select the optimal technique according to the risk of complications. (author)

  7. Respiratory gated lung CT using 320-row area detector CT

    International Nuclear Information System (INIS)

    Sakamoto, Ryo; Noma, Satoshi; Higashino, Takanori

    2010-01-01

    Three hundred and twenty-row Area Detector CT (ADCT) has made it possible to scan whole lung field with prospective respiratory gated wide volume scan. We evaluated whether the respiratory gated wide volume scan enables to reduce motion induced artifacts in the lung area. Helical scan and respiratory gated wide volume scan were performed in 5 patients and 10 healthy volunteers under spontaneous breathing. Significant reduction of motion artifact and superior image quality were obtained in respiratory gated scan in comparison with helical scan. Respiratory gated wide volume scan is an unique method using ADCT, and is able to reduce motion artifacts in lung CT scans of patients unable to suspend respiration in clinical scenes. (author)

  8. Accuracy and Consistency of Respiratory Gating in Abdominal Cancer Patients

    International Nuclear Information System (INIS)

    Ge, Jiajia; Santanam, Lakshmi; Yang, Deshan; Parikh, Parag J.

    2013-01-01

    Purpose: To evaluate respiratory gating accuracy and intrafractional consistency for abdominal cancer patients treated with respiratory gated treatment on a regular linear accelerator system. Methods and Materials: Twelve abdominal patients implanted with fiducials were treated with amplitude-based respiratory-gated radiation therapy. On the basis of daily orthogonal fluoroscopy, the operator readjusted the couch position and gating window such that the fiducial was within a setup margin (fiducial-planning target volume [f-PTV]) when RPM indicated “beam-ON.” Fifty-five pre- and post-treatment fluoroscopic movie pairs with synchronized respiratory gating signal were recorded. Fiducial motion traces were extracted from the fluoroscopic movies using a template matching algorithm and correlated with f-PTV by registering the digitally reconstructed radiographs with the fluoroscopic movies. Treatment was determined to be “accurate” if 50% of the fiducial area stayed within f-PTV while beam-ON. For movie pairs that lost gating accuracy, a MATLAB program was used to assess whether the gating window was optimized, the external-internal correlation (EIC) changed, or the patient moved between movies. A series of safety margins from 0.5 mm to 3 mm was added to f-PTV for reassessing gating accuracy. Results: A decrease in gating accuracy was observed in 44% of movie pairs from daily fluoroscopic movies of 12 abdominal patients. Three main causes for inaccurate gating were identified as change of global EIC over time (∼43%), suboptimal gating setup (∼37%), and imperfect EIC within movie (∼13%). Conclusions: Inconsistent respiratory gating accuracy may occur within 1 treatment session even with a daily adjusted gating window. To improve or maintain gating accuracy during treatment, we suggest using at least a 2.5-mm safety margin to account for gating and setup uncertainties

  9. Evaluation of the new respiratory gating system

    Science.gov (United States)

    Shi, Chengyu; Tang, Xiaoli; Chan, Maria

    2018-01-01

    Objective The newly released Respiratory Gating for Scanners (RGSC; Varian Medical Systems, Palo Alto, CA, USA) system has limited existing quality assurance (QA) protocols and pertinent publications. Herein, we report our experiences of the RGSC system acceptance and QA. Methods The RGSC system integration was tested with peripheral equipment, spatial reproducibility, and dynamic localization accuracy for regular and irregular breathing patterns, respectively. A QUASAR Respiratory Motion Phantom and a mathematical fitting method were used for data acquisition and analysis. Results The results showed that the RGSC system could accurately measure regular motion periods of 3–10 s. For irregular breathing patterns, differences from the existing Real-time Position Management (RPM; Varian Medical Systems, Palo Alto, CA) system were observed. For dynamic localization measurements, the RGSC system showed 76% agreement with the programmed test data within ±5% tolerance in terms of fitting period. As s comparison, the RPM system showed 66% agreement within ±5% tolerance, and 65% for the RGSC versus RPM measurements. Conclusions New functions and positioning accuracy improve the RGSC system’s ability to achieve higher dynamic treatment precision. A 4D phantom is helpful for the QA tests. Further investigation is required for the whole RGSC system performance QA. PMID:29722356

  10. Intrinsic respiratory gating in small-animal CT

    International Nuclear Information System (INIS)

    Bartling, Soenke H.; Dinkel, Julien; Kauczor, Hans-Ulrich; Stiller, Wolfram; Semmler, Wolfhard; Grasruck, Michael; Madisch, Ijad; Gupta, Rajiv; Kiessling, Fabian

    2008-01-01

    Gating in small-animal CT imaging can compensate artefacts caused by physiological motion during scanning. However, all published gating approaches for small animals rely on additional hardware to derive the gating signals. In contrast, in this study a novel method of intrinsic respiratory gating of rodents was developed and tested for mice (n=5), rats (n=5) and rabbits (n=2) in a flat-panel cone-beam CT system. In a consensus read image quality was compared with that of non-gated and retrospective extrinsically gated scans performed using a pneumatic cushion. In comparison to non-gated images, image quality improved significantly using intrinsic and extrinsic gating. Delineation of diaphragm and lung structure improved in all animals. Image quality of intrinsically gated CT was judged to be equivalent to extrinsically gated ones. Additionally 4D datasets were calculated using both gating methods. Values for expiratory, inspiratory and tidal lung volumes determined with the two gating methods were comparable and correlated well with values known from the literature. We could show that intrinsic respiratory gating in rodents makes additional gating hardware and preparatory efforts superfluous. This method improves image quality and allows derivation of functional data. Therefore it bears the potential to find wide applications in small-animal CT imaging. (orig.)

  11. Respiratory guiding system for respiratory motion management in respiratory gated radiotherapy

    International Nuclear Information System (INIS)

    Kang, Seong Hee; Kim, Dong Su; Kim, Tae Ho; Suh, Tae Suk

    2013-01-01

    Respiratory guiding systems have been shown to improve the respiratory regularity. This, in turn, improves the efficiency of synchronized moving aperture radiation therapy, and it reduces the artifacts caused by irregular breathing in imaging techniques such as four-dimensional computed tomography (4D CT), which is used for treatment planning in RGRT. We have previously developed a respiratory guiding system that incorporates an individual-specific guiding waveform, which is easy to follow for each volunteer, to improve the respiratory regularity. The present study evaluates the application of this system to improve the respiratory regularity for respiratory-gated radiation therapy (RGRT). In this study, we evaluated the effectiveness of an in-house-developed respiratory guiding system incorporating an individual specific guiding waveform to improve the respiratory regularity for RGRT. Most volunteers showed significantly less residual motion at each phase during guided breathing owing to the improvement in respiratory regularity. Therefore, the respiratory guiding system can clearly reduce the residual, or respiratory, motion in each phase. From the result, the CTV and the PTV margins during RGRT can be reduced by using the respiratory guiding system, which reduces the residual motions, thus improving the accuracy of RGRT

  12. Respiratory gating in positron emission tomography: A quantitative comparison of different gating schemes

    International Nuclear Information System (INIS)

    Dawood, Mohammad; Buether, Florian; Lang, Norbert; Schober, Otmar; Schaefers, Klaus P

    2007-01-01

    Respiratory gating is used for reducing the effects of breathing motion in a wide range of applications from radiotherapy treatment to diagnostical imaging. Different methods are feasible for respiratory gating. In this study seven gating methods were developed and tested on positron emission tomography (PET) listmode data. The results of seven patient studies were compared quantitatively with respect to motion and noise. (1) Equal and (2) variable time-based gating methods use only the time information of the breathing cycle to define respiratory gates. (3) Equal and (4) variable amplitude-based gating approaches utilize the amplitude of the respiratory signal. (5) Cycle-based amplitude gating is a combination of time and amplitude-based techniques. A baseline correction was applied to methods (3) and (4) resulting in two new approaches: Baseline corrected (6) equal and (7) variable amplitude-based gating. Listmode PET data from seven patients were acquired together with a respiratory signal. Images were reconstructed applying the seven gating methods. Two parameters were used to quantify the results: Motion was measured as the displacement of the heart due to respiration and noise was defined as the standard deviation of pixel intensities in a background region. The amplitude-based approaches (3) and (4) were superior to the time-based methods (1) and (2). The improvement in capturing the motion was more than 30% (up to 130%) in all subjects. The variable time (2) and amplitude (4) methods had a more uniform noise distribution among all respiratory gates compared to equal time (1) and amplitude (3) methods. Baseline correction did not improve the results. Out of seven different respiratory gating approaches, the variable amplitude method (4) captures the respiratory motion best while keeping a constant noise level among all respiratory phases

  13. Dynamic gating window for compensation of baseline shift in respiratory-gated radiation therapy

    International Nuclear Information System (INIS)

    Pepin, Eric W.; Wu Huanmei; Shirato, Hiroki

    2011-01-01

    Purpose: To analyze and evaluate the necessity and use of dynamic gating techniques for compensation of baseline shift during respiratory-gated radiation therapy of lung tumors. Methods: Motion tracking data from 30 lung tumors over 592 treatment fractions were analyzed for baseline shift. The finite state model (FSM) was used to identify the end-of-exhale (EOE) breathing phase throughout each treatment fraction. Using duty cycle as an evaluation metric, several methods of end-of-exhale dynamic gating were compared: An a posteriori ideal gating window, a predictive trend-line-based gating window, and a predictive weighted point-based gating window. These methods were evaluated for each of several gating window types: Superior/inferior (SI) gating, anterior/posterior beam, lateral beam, and 3D gating. Results: In the absence of dynamic gating techniques, SI gating gave a 39.6% duty cycle. The ideal SI gating window yielded a 41.5% duty cycle. The weight-based method of dynamic SI gating yielded a duty cycle of 36.2%. The trend-line-based method yielded a duty cycle of 34.0%. Conclusions: Dynamic gating was not broadly beneficial due to a breakdown of the FSM's ability to identify the EOE phase. When the EOE phase was well defined, dynamic gating showed an improvement over static-window gating.

  14. Retrospective data-driven respiratory gating for PET/CT

    International Nuclear Information System (INIS)

    Schleyer, Paul J; O'Doherty, Michael J; Barrington, Sally F; Marsden, Paul K

    2009-01-01

    Respiratory motion can adversely affect both PET and CT acquisitions. Respiratory gating allows an acquisition to be divided into a series of motion-reduced bins according to the respiratory signal, which is typically hardware acquired. In order that the effects of motion can potentially be corrected for, we have developed a novel, automatic, data-driven gating method which retrospectively derives the respiratory signal from the acquired PET and CT data. PET data are acquired in listmode and analysed in sinogram space, and CT data are acquired in cine mode and analysed in image space. Spectral analysis is used to identify regions within the CT and PET data which are subject to respiratory motion, and the variation of counts within these regions is used to estimate the respiratory signal. Amplitude binning is then used to create motion-reduced PET and CT frames. The method was demonstrated with four patient datasets acquired on a 4-slice PET/CT system. To assess the accuracy of the data-derived respiratory signal, a hardware-based signal was acquired for comparison. Data-driven gating was successfully performed on PET and CT datasets for all four patients. Gated images demonstrated respiratory motion throughout the bin sequences for all PET and CT series, and image analysis and direct comparison of the traces derived from the data-driven method with the hardware-acquired traces indicated accurate recovery of the respiratory signal.

  15. Respiratory trace feature analysis for the prediction of respiratory-gated PET quantification

    Science.gov (United States)

    Wang, Shouyi; Bowen, Stephen R.; Chaovalitwongse, W. Art; Sandison, George A.; Grabowski, Thomas J.; Kinahan, Paul E.

    2014-02-01

    The benefits of respiratory gating in quantitative PET/CT vary tremendously between individual patients. Respiratory pattern is among many patient-specific characteristics that are thought to play an important role in gating-induced imaging improvements. However, the quantitative relationship between patient-specific characteristics of respiratory pattern and improvements in quantitative accuracy from respiratory-gated PET/CT has not been well established. If such a relationship could be estimated, then patient-specific respiratory patterns could be used to prospectively select appropriate motion compensation during image acquisition on a per-patient basis. This study was undertaken to develop a novel statistical model that predicts quantitative changes in PET/CT imaging due to respiratory gating. Free-breathing static FDG-PET images without gating and respiratory-gated FDG-PET images were collected from 22 lung and liver cancer patients on a PET/CT scanner. PET imaging quality was quantified with peak standardized uptake value (SUVpeak) over lesions of interest. Relative differences in SUVpeak between static and gated PET images were calculated to indicate quantitative imaging changes due to gating. A comprehensive multidimensional extraction of the morphological and statistical characteristics of respiratory patterns was conducted, resulting in 16 features that characterize representative patterns of a single respiratory trace. The six most informative features were subsequently extracted using a stepwise feature selection approach. The multiple-regression model was trained and tested based on a leave-one-subject-out cross-validation. The predicted quantitative improvements in PET imaging achieved an accuracy higher than 90% using a criterion with a dynamic error-tolerance range for SUVpeak values. The results of this study suggest that our prediction framework could be applied to determine which patients would likely benefit from respiratory motion compensation

  16. Respiratory trace feature analysis for the prediction of respiratory-gated PET quantification

    International Nuclear Information System (INIS)

    Wang, Shouyi; Chaovalitwongse, W Art; Bowen, Stephen R; Kinahan, Paul E; Sandison, George A; Grabowski, Thomas J

    2014-01-01

    The benefits of respiratory gating in quantitative PET/CT vary tremendously between individual patients. Respiratory pattern is among many patient-specific characteristics that are thought to play an important role in gating-induced imaging improvements. However, the quantitative relationship between patient-specific characteristics of respiratory pattern and improvements in quantitative accuracy from respiratory-gated PET/CT has not been well established. If such a relationship could be estimated, then patient-specific respiratory patterns could be used to prospectively select appropriate motion compensation during image acquisition on a per-patient basis. This study was undertaken to develop a novel statistical model that predicts quantitative changes in PET/CT imaging due to respiratory gating. Free-breathing static FDG-PET images without gating and respiratory-gated FDG-PET images were collected from 22 lung and liver cancer patients on a PET/CT scanner. PET imaging quality was quantified with peak standardized uptake value (SUV peak ) over lesions of interest. Relative differences in SUV peak between static and gated PET images were calculated to indicate quantitative imaging changes due to gating. A comprehensive multidimensional extraction of the morphological and statistical characteristics of respiratory patterns was conducted, resulting in 16 features that characterize representative patterns of a single respiratory trace. The six most informative features were subsequently extracted using a stepwise feature selection approach. The multiple-regression model was trained and tested based on a leave-one-subject-out cross-validation. The predicted quantitative improvements in PET imaging achieved an accuracy higher than 90% using a criterion with a dynamic error-tolerance range for SUV peak values. The results of this study suggest that our prediction framework could be applied to determine which patients would likely benefit from respiratory motion

  17. Respiratory gated radiotherapy: current techniques and potential benefits

    International Nuclear Information System (INIS)

    Giraud, P.; Campana, F.; Rosenwald, J.C.; Cosset, J.M.; Reboul, F.; Garcia, R.; Clippe, S.; Carrie, C.; Dubray, B.

    2003-01-01

    Respiration-gated radiotherapy offers a significant potential for improvement in the irradiation of tumor sites affected by respiratory motion such as lung, breast and liver tumors. An increased conformality of irradiation fields leading to decreased complications rates of organs at risk (lung, heart...) is expected. Respiratory gating is in line with the need for improved precision required by radiotherapy techniques such as 3D conformal radiotherapy or intensity modulated radiotherapy. Reduction of respiratory motion can be achieved by using either breath hold techniques or respiration synchronized gating techniques. Breath-hold techniques can be achieved with active, in which airflow of the patient is temporarily blocked by a valve, or passive techniques, in which the patient voluntarily breath-hold. Synchronized gating techniques use external devices to predict the phase of the respiration cycle while the patient breaths freely. These techniques presently investigated in several medical centers worldwide. Although promising, the first results obtained in lung and liver cancer patients require confirmation. Physical, technical and physiological questions still remain to be answered. This paper describes the most frequently used gated techniques and the main published clinical reports on the use of respiration-gated radiotherapy in order to evaluate the impact of these techniques. (author)

  18. Respiratory gated beam delivery cannot facilitate margin reduction, unless combined with respiratory correlated image guidance

    International Nuclear Information System (INIS)

    Korreman, Stine S.; Juhler-Nottrup, Trine; Boyer, Arthur L.

    2008-01-01

    Purpose/objective: In radiotherapy of targets moving with respiration, beam gating is offered as a means of reducing the target motion. The purpose of this study is to evaluate the safe magnitude of margin reduction for respiratory gated beam delivery. Materials/methods: The study is based on data for 17 lung cancer patients in separate protocols at Rigshospitalet and Stanford Cancer Center. Respiratory curves for external optical markers and implanted fiducials were collected using equipment based on the RPM system (Varian Medical Systems). A total of 861 respiratory curves represented external measurements over 30 fraction treatment courses for 10 patients, and synchronous external/internal measurements in single sessions for seven patients. Variations in respiratory amplitude (simulated coaching) and external/internal phase shifts were simulated by perturbation with realistic values. Variations were described by medians and standard deviations (SDs) of position distributions of the markers. Gating windows (35% duty cycle) were retrospectively applied to the respiratory data for each session, mimicking the use of commercially available gating systems. Medians and SDs of gated data were compared to those of ungated data, to assess potential margin reductions. Results: External respiratory data collected over entire treatment courses showed SDs from 1.6 to 8.1 mm, the major part arising from baseline variations. The gated data had SDs from 1.5 to 7.7 mm, with a mean reduction of 0.3 mm (6%). Gated distributions were more skewed than ungated, and in a few cases a marginal miss of gated respiration would be found even if no margin reduction was applied. Regularization of breathing amplitude to simulate coaching did not alter these results significantly. Simulation of varying phase shifts between internal and external respiratory signals showed that the SDs of gated distributions were the same as for the ungated or smaller, but the median values were markedly shifted

  19. Dose verification for respiratory-gated volumetric modulated arc therapy

    Energy Technology Data Exchange (ETDEWEB)

    Qian Jianguo; Xing Lei; Liu Wu; Luxton, Gary, E-mail: gluxton@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305 (United States)

    2011-08-07

    A novel commercial medical linac system (TrueBeam(TM), Varian Medical Systems, Palo Alto, CA) allows respiratory-gated volumetric modulated arc therapy (VMAT), a new modality for treating moving tumors with high precision and improved accuracy by allowing for regular motion associated with a patient's breathing during VMAT delivery. The purpose of this work is to adapt a previously-developed dose reconstruction technique to evaluate the fidelity of VMAT treatment during gated delivery under clinic-relevant periodic motion related to patient breathing. A Varian TrueBeam system was used in this study. VMAT plans were created for three patients with lung or pancreas tumors. Conventional 6 and 15 MV beams with flattening filter and high-dose-rate 10 MV beams with no flattening filter were used in these plans. Each patient plan was delivered to a phantom first without gating and then with gating for three simulated respiratory periods (3, 4.5 and 6 s). Using the adapted log-file-based dose reconstruction procedure supplemented with ion chamber array (Seven29(TM), PTW, Freiburg, Germany) measurements, the delivered dose was used to evaluate the fidelity of gated VMAT delivery. Comparison of Seven29 measurements with and without gating showed good agreement with gamma-index passing rates above 99% for 1%/1 mm dose accuracy/distance-to-agreement criteria. With original plans as reference, gamma-index passing rates were 100% for the reconstituted plans (1%/1 mm criteria) and 93.5-100% for gated Seven29 measurements (3%/3 mm criteria). In the presence of leaf error deliberately introduced into the gated delivery of a pancreas patient plan, both dose reconstruction and Seven29 measurement consistently indicated substantial dosimetric differences from the original plan. In summary, a dose reconstruction procedure was demonstrated for evaluating the accuracy of respiratory-gated VMAT delivery. This technique showed that under clinical operation, the TrueBeam system

  20. Dosimetric Analysis of Respiratory-Gated Radiotherapy for Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Xi Mian; Zhang Li; Liu Mengzhong; Deng Xiaowu; Huang Xiaoyan; Liu Hui

    2011-01-01

    The purpose of this study was to define individualized internal target volume (ITV) for hepatocellular carcinoma (HCC) using 4D computed tomography (4DCT), and to determine the geometric and dosimetric benefits of respiratory gating. Gross tumor volumes (GTVs) were contoured on 10 respiratory phases of 4DCT images for 12 patients with HCC. Three treatment plans were prepared using different planning target volumes (PTVs): (1) PTV 3D , derived from a single helical clinical target volume (CTV) plus conventional margins; (2) PTV 10phases , derived from ITV 10phases , which encompassed all 10 CTVs plus an isotropic margin of 0.8 cm; (3) PTV gating , derived from ITV gating , which encompassed three CTVs within gating-window at end-expiration plus an isotropic margin of 0.8 cm. The PTV 3D was the largest volume for all patients. The ITV-based plans and gating plans spared more normal tissues than 3D plans, especially the liver. Without increasing normal tissue complication probability of the 3D plans, the ITV-based plans allowed for increasing the calculated dose from 50.8 Gy to 54.7 Gy on average, and the gating plans could further escalate the dose to 58.5 Gy. Compared with ITV-based plans, the dosimetric gains with gating plan strongly correlated with GTV mobility in the craniocaudal direction. The ITV-based plans can ensure target coverage with less irradiation of normal tissues compared with 3D plans. Respiratory-gated radiotherapy can further reduce the target volumes to spare more surrounding tissues and allow dose escalation, especially for patients with tumor mobility >1 cm.

  1. Respiratory signal analysis of liver cancer patients with respiratory-gated radiation therapy

    International Nuclear Information System (INIS)

    Kang, Dong Im; Jung, Sang Hoon; Kim, Chul Jong; Park, Hee Chul; Choi, Byung Ki

    2015-01-01

    External markers respiratory movement measuring device (RPM; Real-time Position Management, Varian Medical System, USA) Liver Cancer Radiation Therapy Respiratory gated with respiratory signal with irradiation time and the actual research by analyzing the respiratory phase with the breathing motion measurement device respiratory tuning evaluate the accuracy of radiation therapy May-September 2014 Novalis Tx. (Varian Medical System, USA) and liver cancer radiotherapy using respiratory gated RPM (Duty Cycle 20%, Gating window 40%-60%) of 16 patients who underwent total when recording the analyzed respiratory movement. After the breathing motion of the external markers recorded on the RPM was reconstructed by breathing through the acts phase analysis, for Beam-on Time and Duty Cycle recorded by using the reconstructed phase breathing breathing with RPM gated the prediction accuracy of the radiation treatment analysis and analyzed the correlation between prediction accuracy and Duty Cycle in accordance with the reproducibility of the respiratory movement. Treatment of 16 patients with respiratory cycle during the actual treatment plan was analyzed with an average difference -0.03 seconds (range -0.50 seconds to 0.09 seconds) could not be confirmed statistically significant difference between the two breathing (p = 0.472). The average respiratory period when treatment is 4.02 sec (0.71 sec), the average value of the respiratory cycle of the treatment was characterized by a standard deviation 7.43% (range 2.57 to 19.20%). Duty Cycle is that the actual average 16.05% (range 13.78 to 17.41%), average 56.05 got through the acts of the show and then analyzed% (range 39.23 to 75.10%) is planned in respiratory research phase (40% to 60%) in was confirmed. The investigation on the correlation between the ratio Duty Cycle and planned respiratory phase and the standard deviation of the respiratory cycle was analyzed in each -0.156 (p = 0.282) and -0.385 (p = 0.070). This study is

  2. Dose profile measurements during respiratory-gated lung stereotactic radiotherapy: A phantom study

    International Nuclear Information System (INIS)

    Jong, W L; Ung, N M; Wong, J H D; Ng, K H

    2016-01-01

    During stereotactic body radiotherapy, high radiation dose (∼60 Gy) is delivered to the tumour in small fractionation regime. In this study, the dosimetric characteristics were studied using radiochromic film during respiratory-gated and non-gated lung stereotactic body radiotherapy (SBRT). Specifically, the effect of respiratory cycle and amplitude, as well as gating window on the dosimetry were studied. In this study, the dose profiles along the irradiated area were measured. The dose profiles for respiratory-gated radiation delivery with different respiratory or tumour motion amplitudes, gating windows and respiratory time per cycle were in agreement with static radiation delivery. The respiratory gating system was able to deliver the radiation dose accurately (±1.05 mm) in the longitudinal direction. Although the treatment time for respiratory-gated SBRT was prolonged, this approach can potentially reduce the margin for internal tumour volume without compromising the tumour coverage. In addition, the normal tissue sparing effect can be improved. (paper)

  3. Respiratory gated beam delivery cannot facilitate margin reduction, unless combined with respiratory correlated image guidance

    DEFF Research Database (Denmark)

    Korreman, S.S.; Boyer, A.L.; Juhler-Nøttrup, Trine

    2008-01-01

    PURPOSE/OBJECTIVE: In radiotherapy of targets moving with respiration, beam gating is offered as a means of reducing the target motion. The purpose of this study is to evaluate the safe magnitude of margin reduction for respiratory gated beam delivery. MATERIALS/METHODS: The study is based on data...... for 17 lung cancer patients in separate protocols at Rigshospitalet and Stanford Cancer Center. Respiratory curves for external optical markers and implanted fiducials were collected using equipment based on the RPM system (Varian Medical Systems). A total of 861 respiratory curves represented external...... measurements over 30 fraction treatment courses for 10 patients, and synchronous external/internal measurements in single sessions for seven patients. Variations in respiratory amplitude (simulated coaching) and external/internal phase shifts were simulated by perturbation with realistic values. Variations...

  4. Determination of prospective displacement-based gate threshold for respiratory-gated radiation delivery from retrospective phase-based gate threshold selected at 4D CT simulation

    International Nuclear Information System (INIS)

    Vedam, S.; Archambault, L.; Starkschall, G.; Mohan, R.; Beddar, S.

    2007-01-01

    Four-dimensional (4D) computed tomography (CT) imaging has found increasing importance in the localization of tumor and surrounding normal structures throughout the respiratory cycle. Based on such tumor motion information, it is possible to identify the appropriate phase interval for respiratory gated treatment planning and delivery. Such a gating phase interval is determined retrospectively based on tumor motion from internal tumor displacement. However, respiratory-gated treatment is delivered prospectively based on motion determined predominantly from an external monitor. Therefore, the simulation gate threshold determined from the retrospective phase interval selected for gating at 4D CT simulation may not correspond to the delivery gate threshold that is determined from the prospective external monitor displacement at treatment delivery. The purpose of the present work is to establish a relationship between the thresholds for respiratory gating determined at CT simulation and treatment delivery, respectively. One hundred fifty external respiratory motion traces, from 90 patients, with and without audio-visual biofeedback, are analyzed. Two respiratory phase intervals, 40%-60% and 30%-70%, are chosen for respiratory gating from the 4D CT-derived tumor motion trajectory. From residual tumor displacements within each such gating phase interval, a simulation gate threshold is defined based on (a) the average and (b) the maximum respiratory displacement within the phase interval. The duty cycle for prospective gated delivery is estimated from the proportion of external monitor displacement data points within both the selected phase interval and the simulation gate threshold. The delivery gate threshold is then determined iteratively to match the above determined duty cycle. The magnitude of the difference between such gate thresholds determined at simulation and treatment delivery is quantified in each case. Phantom motion tests yielded coincidence of simulation

  5. Audio-visual biofeedback for respiratory-gated radiotherapy: Impact of audio instruction and audio-visual biofeedback on respiratory-gated radiotherapy

    International Nuclear Information System (INIS)

    George, Rohini; Chung, Theodore D.; Vedam, Sastry S.; Ramakrishnan, Viswanathan; Mohan, Radhe; Weiss, Elisabeth; Keall, Paul J.

    2006-01-01

    Purpose: Respiratory gating is a commercially available technology for reducing the deleterious effects of motion during imaging and treatment. The efficacy of gating is dependent on the reproducibility within and between respiratory cycles during imaging and treatment. The aim of this study was to determine whether audio-visual biofeedback can improve respiratory reproducibility by decreasing residual motion and therefore increasing the accuracy of gated radiotherapy. Methods and Materials: A total of 331 respiratory traces were collected from 24 lung cancer patients. The protocol consisted of five breathing training sessions spaced about a week apart. Within each session the patients initially breathed without any instruction (free breathing), with audio instructions and with audio-visual biofeedback. Residual motion was quantified by the standard deviation of the respiratory signal within the gating window. Results: Audio-visual biofeedback significantly reduced residual motion compared with free breathing and audio instruction. Displacement-based gating has lower residual motion than phase-based gating. Little reduction in residual motion was found for duty cycles less than 30%; for duty cycles above 50% there was a sharp increase in residual motion. Conclusions: The efficiency and reproducibility of gating can be improved by: incorporating audio-visual biofeedback, using a 30-50% duty cycle, gating during exhalation, and using displacement-based gating

  6. Automatic tumour volume delineation in respiratory-gated PET images

    International Nuclear Information System (INIS)

    Gubbi, Jayavardhana; Palaniswami, Marimuthu; Kanakatte, Aparna; Mani, Nallasamy; Kron, Tomas; Binns, David; Srinivasan, Bala

    2011-01-01

    Positron emission tomography (PET) is a state-of-the-art functional imaging technique used in the accurate detection of cancer. The main problem with the tumours present in the lungs is that they are non-stationary during each respiratory cycle. Tumours in the lungs can get displaced up to 2.5 cm during respiration. Accurate detection of the tumour enables avoiding the addition of extra margin around the tumour that is usually used during radiotherapy treatment planning. This paper presents a novel method to detect and track tumour in respiratory-gated PET images. The approach followed to achieve this task is to automatically delineate the tumour from the first frame using support vector machines. The resulting volume and position information from the first frame is used in tracking its motion in the subsequent frames with the help of level set (LS) deformable model. An excellent accuracy of 97% is obtained using wavelets and support vector machines. The volume calculated as a result of the machine learning (ML) stage is used as a constraint for deformable models and the tumour is tracked in the remaining seven phases of the respiratory cycle. As a result, the complete information about tumour movement during each respiratory cycle is available in relatively short time. The combination of the LS and ML approach accurately delineated the tumour volume from all frames, thereby providing a scope of using PET images towards planning an accurate and effective radiotherapy treatment for lung cancer.

  7. Role of respiratory-gated PET/CT for pancreatic tumors: A preliminary result

    International Nuclear Information System (INIS)

    Kasuya, Takeo; Tateishi, Ukihide; Suzuki, Kazufumi; Daisaki, Hiromitsu; Nishiyama, Yuji; Hata, Masaharu; Inoue, Tomio

    2013-01-01

    Purpose: The aim of this study is to ascertain role of respiratory-gated PET/CT for accurate diagnosis of pancreatic tumors. Materials and methods: Prior to clinical study, the phantom study was performed to evaluate the impact of respiratory motion on lesion quantification. Twenty-two patients (mean age 65 years) with pancreatic tumors were enrolled. Pathological diagnoses by surgical specimens consisted of pancreatic cancer (n = 15) and benign intraductal papillary mucinous neoplasm (IPMN, n = 7). Whole-body scan of non-respiratory-gated PET/CT was performed at first, and subsequent respiratory-gated PET/CT for one bed position was performed. All PET/CT studies were performed prior to surgery. The SUV max obtained by non-respiratory-gated PET/CT and respiratory-gated PET/CT, and percent difference in SUVmax (%SUVmax) were compared. Results: The profile curve of 5 respiratory bin image was most similar to that of static image. The third bin of 5 respiratory bin image showed highest FWHM (24.0 mm) and FWTM (32.7 mm). The mean SUVmax of pancreatic cancer was similar to that of benign IPMN on non-respiratory-gated PET/CT (p = 0.05), whereas significant difference was found between two groups on respiratory-gated PET/CT (p = 0.016). The mean %SUV of pancreatic cancer was greater than that of benign IPMN (p < 0.0001). Identification of the primary tumor in pancreatic head (n = 13, 59%) was improved by using respiratory-gated PET/CT because of minimal affection of physiological accumulation in duodenum. Conclusion: Respiratory-gated PET/CT is a feasible technique for evaluation of pancreatic tumors and allows more accurate identification of pancreatic tumors compared with non-respiratory-gated PET/CT

  8. The clinical implementation of respiratory-gated intensity-modulated radiotherapy

    International Nuclear Information System (INIS)

    Keall, Paul; Vedam, Sastry; George, Rohini; Bartee, Chris; Siebers, Jeffrey; Lerma, Fritz; Weiss, Elisabeth; Chung, Theodore

    2006-01-01

    The clinical use of respiratory-gated radiotherapy and the application of intensity-modulated radiotherapy (IMRT) are 2 relatively new innovations to the treatment of lung cancer. Respiratory gating can reduce the deleterious effects of intrafraction motion, and IMRT can concurrently increase tumor dose homogeneity and reduce dose to critical structures including the lungs, spinal cord, esophagus, and heart. The aim of this work is to describe the clinical implementation of respiratory-gated IMRT for the treatment of non-small cell lung cancer. Documented clinical procedures were developed to include a tumor motion study, gated CT imaging, IMRT treatment planning, and gated IMRT delivery. Treatment planning procedures for respiratory-gated IMRT including beam arrangements and dose-volume constraints were developed. Quality assurance procedures were designed to quantify both the dosimetric and positional accuracy of respiratory-gated IMRT, including film dosimetry dose measurements and Monte Carlo dose calculations for verification and validation of individual patient treatments. Respiratory-gated IMRT is accepted by both treatment staff and patients. The dosimetric and positional quality assurance test results indicate that respiratory-gated IMRT can be delivered accurately. If carefully implemented, respiratory-gated IMRT is a practical alternative to conventional thoracic radiotherapy. For mobile tumors, respiratory-gated radiotherapy is used as the standard of care at our institution. Due to the increased workload, the choice of IMRT is taken on a case-by-case basis, with approximately half of the non-small cell lung cancer patients receiving respiratory-gated IMRT. We are currently evaluating whether superior tumor coverage and limited normal tissue dosing will lead to improvements in local control and survival in non-small cell lung cancer

  9. 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.

  10. Acquisition and automated 3-D segmentation of respiratory/cardiac-gated PET transmission images

    International Nuclear Information System (INIS)

    Reutter, B.W.; Klein, G.J.; Brennan, K.M.; Huesman, R.H.

    1996-01-01

    To evaluate the impact of respiratory motion on attenuation correction of cardiac PET data, we acquired and automatically segmented gated transmission data for a dog breathing on its own under gas anesthesia. Data were acquired for 20 min on a CTI/Siemens ECAT EXACT HR (47-slice) scanner configured for 12 gates in a static study, Two respiratory gates were obtained using data from a pneumatic bellows placed around the dog's chest, in conjunction with 6 cardiac gates from standard EKG gating. Both signals were directed to a LabVIEW-controlled Macintosh, which translated them into one of 12 gate addresses. The respiratory gating threshold was placed near end-expiration to acquire 6 cardiac-gated datasets at end-expiration and 6 cardiac-gated datasets during breaths. Breaths occurred about once every 10 sec and lasted about 1-1.5 sec. For each respiratory gate, data were summed over cardiac gates and torso and lung surfaces were segmented automatically using a differential 3-D edge detection algorithm. Three-dimensional visualizations showed that lung surfaces adjacent to the heart translated 9 mm inferiorly during breaths. Our results suggest that respiration-compensated attenuation correction is feasible with a modest amount of gated transmission data and is necessary for accurate quantitation of high-resolution gated cardiac PET data

  11. Evaluation of the Usefulness of the Respiratory Guidance System in the Respiratory Gating Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yeong Cheol; Kim, Sun Myung; Do, Gyeong Min; Park, Geun Yong; Kim, Gun Oh; Kim, Young Bum [Dept. of Radiation Oncology, Guro Hospital, Korea Univeristy, Seoul (Korea, Republic of)

    2012-09-15

    The respiration is one of the most important factors in respiratory gating radiation therapy (RGRT). We have developed an unique respiratory guidance system using an audio-visual system in order to support and stabilize individual patient's respiration and evaluated the usefulness of this system. Seven patients received the RGRT at our clinic from June 2011 to April 2012. After breathing exercise standard deviations by the superficial contents of respiratory cycles and functions, and analyzed them to examine changes in their breathing before and with the audio-visual system, we measured their spontaneous respiration and their respiration with the audio-visual system respectively. With the measured data, we yielded after the therapy. The PTP (peak to peak) of the standard deviations of the free breathing, the audio guidance system, and the respiratory guidance system were 0.343, 0.148, and 0.078 respectively. The respiratory cycles were 0.645, 0.345, and 0.171 respectively and the superficial contents of the respiratory functions were 2.591, 1.008, and 0.877 respectively. The average values of the differences in the standard deviations among the whole patients at the CT room and therapy room were 0.425 for the PTP, 1.566 for the respiratory cycles, and 3.671 for the respiratory superficial contents. As for the standard deviations before and after the application of the PTP respiratory guidance system, that of the PTP was 0.265, that of the respiratory cycles was 0.474, and that of the respiratory superficial contents. The results of t-test of the values before and after free breathing and the audio-visual guidance system showed that the P-value of the PTP was 0.035, that of the cycles 0.009, and that of the respiratory superficial contents 0.010. The respiratory control could be one of the most important factors in the RGRT which determines the success or failure of a treatment. We were able to get more stable breathing with the audio-visual respiratory

  12. Evaluation of the Usefulness of the Respiratory Guidance System in the Respiratory Gating Radiation Therapy

    International Nuclear Information System (INIS)

    Lee, Yeong Cheol; Kim, Sun Myung; Do, Gyeong Min; Park, Geun Yong; Kim, Gun Oh; Kim, Young Bum

    2012-01-01

    The respiration is one of the most important factors in respiratory gating radiation therapy (RGRT). We have developed an unique respiratory guidance system using an audio-visual system in order to support and stabilize individual patient's respiration and evaluated the usefulness of this system. Seven patients received the RGRT at our clinic from June 2011 to April 2012. After breathing exercise standard deviations by the superficial contents of respiratory cycles and functions, and analyzed them to examine changes in their breathing before and with the audio-visual system, we measured their spontaneous respiration and their respiration with the audio-visual system respectively. With the measured data, we yielded after the therapy. The PTP (peak to peak) of the standard deviations of the free breathing, the audio guidance system, and the respiratory guidance system were 0.343, 0.148, and 0.078 respectively. The respiratory cycles were 0.645, 0.345, and 0.171 respectively and the superficial contents of the respiratory functions were 2.591, 1.008, and 0.877 respectively. The average values of the differences in the standard deviations among the whole patients at the CT room and therapy room were 0.425 for the PTP, 1.566 for the respiratory cycles, and 3.671 for the respiratory superficial contents. As for the standard deviations before and after the application of the PTP respiratory guidance system, that of the PTP was 0.265, that of the respiratory cycles was 0.474, and that of the respiratory superficial contents. The results of t-test of the values before and after free breathing and the audio-visual guidance system showed that the P-value of the PTP was 0.035, that of the cycles 0.009, and that of the respiratory superficial contents 0.010. The respiratory control could be one of the most important factors in the RGRT which determines the success or failure of a treatment. We were able to get more stable breathing with the audio-visual respiratory guidance

  13. MR respiratory navigator echo gated coronary angiography at 3 T

    International Nuclear Information System (INIS)

    Chang Shixin; Wang Yibin; Zong Genlin; Hao Nanxin; Du Yushan

    2007-01-01

    Objective: To investigate the techniques and influence factors for the respiratory navigator echo triggered whole-heart coronary MR angiography (WH-CMRA) and evaluate its application in visualizing coronary arteries and the image quality. Methods: Ninety two volunteers were acquired with WH-CMRA at 3 T MR scanner using respiratory navigator-echo gated TFE sequence. Imaging quality was visually graded as 0-IV grade according to the visual inspection, average length, diameter and sharpness of coronary arteries. The correlation between the imaging quality and respiratory pattern, heart rate and navigator efficiency was analyzed. Results: The imaging quality in 92 cases was that 28 were graded as IV, 53 were graded as III, 9 were graded as II and 2 were graded as I. The successful rate of scan was 88% (81/92). The imaging quality is mainly graded as IV when the heart rate was less than 75 beats per minute (bpm) and the sharpness of vessel was (48±11)%. When heart rate was more than 75 bpm, the image quality was mostly graded as 111 and the sharpness was (33±15)%. The correlation between heart rate and imaging quality score was negative (r= -0.726, P O.05). Conclusion: 3 T WH-CMRA technique could facilitated the visualization of whole coronary arteries at free breathing but having indications on heart rate. (authors)

  14. An integrated bioimpedance—ECG gating technique for respiratory and cardiac motion compensation in cardiac PET

    International Nuclear Information System (INIS)

    Koivumäki, Tuomas; Nekolla, Stephan G; Fürst, Sebastian; Loher, Simone; Schwaiger, Markus; Vauhkonen, Marko; Hakulinen, Mikko A

    2014-01-01

    Respiratory motion may degrade image quality in cardiac PET imaging. Since cardiac PET studies often involve cardiac gating by ECG, a separate respiratory monitoring system is required increasing the logistic complexity of the examination, in case respiratory gating is also needed. Thus, we investigated the simultaneous acquisition of both respiratory and cardiac gating signals using II limb lead mimicking electrode configuration during cardiac PET scans of 11 patients. In addition to conventional static and ECG-gated images, bioimpedance technique was utilized to generate respiratory- and dual-gated images. The ability of the bioimpedance technique to monitor intrathoracic respiratory motion was assessed estimating cardiac displacement between end-inspiration and -expiration. The relevance of dual gating was evaluated in left ventricular volume and myocardial wall thickness measurements. An average 7.6  ±  3.3 mm respiratory motion was observed in the study population. Dual gating showed a small but significant increase (4 ml, p = 0.042) in left ventricular myocardial volume compared to plain cardiac gating. In addition, a thinner myocardial wall was observed in dual-gated images (9.3  ±  1.3 mm) compared to cardiac-gated images (11.3  ±  1.3 mm, p = 0.003). This study shows the feasibility of bioimpedance measurements for dual gating in a clinical setting. The method enables simultaneous acquisition of respiratory and cardiac gating signals using a single device with standard ECG electrodes. (paper)

  15. Efficiency of respiratory-gated delivery of synchrotron-based pulsed proton irradiation

    International Nuclear Information System (INIS)

    Tsunashima, Yoshikazu; Vedam, Sastry; Dong, Lei; Bues, Martin; Balter, Peter; Smith, Alfred; Mohan, Radhe; Umezawa, Masumi; Sakae, Takeji

    2008-01-01

    Significant differences exist in respiratory-gated proton beam delivery with a synchrotron-based accelerator system when compared to photon therapy with a conventional linear accelerator. Delivery of protons with a synchrotron accelerator is governed by a magnet excitation cycle pattern. Optimal synchronization of the magnet excitation cycle pattern with the respiratory motion pattern is critical to the efficiency of respiratory-gated proton delivery. There has been little systematic analysis to optimize the accelerator's operational parameters to improve gated treatment efficiency. The goal of this study was to estimate the overall efficiency of respiratory-gated synchrotron-based proton irradiation through realistic simulation. Using 62 respiratory motion traces from 38 patients, we simulated respiratory gating for duty cycles of 30%, 20% and 10% around peak exhalation for various fixed and variable magnet excitation patterns. In each case, the time required to deliver 100 monitor units in both non-gated and gated irradiation scenarios was determined. Based on results from this study, the minimum time required to deliver 100 MU was 1.1 min for non-gated irradiation. For respiratory-gated delivery at a 30% duty cycle around peak exhalation, corresponding average delivery times were typically three times longer with a fixed magnet excitation cycle pattern. However, when a variable excitation cycle was allowed in synchrony with the patient's respiratory cycle, the treatment time only doubled. Thus, respiratory-gated delivery of synchrotron-based pulsed proton irradiation is feasible and more efficient when a variable magnet excitation cycle pattern is used

  16. Respiratory gating of cardiac PET data in list-mode acquisition.

    Science.gov (United States)

    Livieratos, Lefteris; Rajappan, Kim; Stegger, Lars; Schafers, Klaus; Bailey, Dale L; Camici, Paolo G

    2006-05-01

    Respiratory motion has been identified as a source of artefacts in most medical imaging modalities. This paper reports on respiratory gating as a means to eliminate motion-related inaccuracies in PET imaging. Respiratory gating was implemented in list mode with physiological signal recorded every millisecond together with the PET data. Respiration was monitored with an inductive respiration monitor using an elasticised belt around the patient's chest. Simultaneous ECG gating can be maintained independently by encoding ECG trigger signal into the list-mode data. Respiratory gating is performed in an off-line workstation with gating parameters defined retrospectively. The technique was applied on a preliminary set of patient data with C(15)O. Motion was visually observed in the cine displays of the sagittal and coronal views of the reconstructed respiratory gated images. Significant changes in the cranial-caudal position of the heart could be observed. The centroid of the cardiac blood pool showed an excursion of 4.5-16.5 mm (mean 8.5+/-4.8 mm) in the cranial-caudal direction, with more limited excursion of 1.1-7.0 mm (mean 2.5+/-2.2 mm) in the horizontal direction and 1.3-3.7 mm (mean 2.4+/-0.9 mm) in the vertical direction. These preliminary data show that the extent of motion involved in respiration is comparable to myocardial wall thickness, and respiratory gating may be considered in order to reduce this effect in the reconstructed images.

  17. Respiratory and cardiac motion correction in dual gated PET/MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fayad, Hadi; Monnier, Florian [LaTIM, INSERM, UMR 1101, Brest (France); Odille, Freedy; Felblinger, Jacques [INSERM U947, University of Nancy, Nancy (France); Lamare, Frederic [INCIA, UMR5287, CNRS, CHU Bordeaux, Bordeaux (France); Visvikis, Dimitris [LaTIM, INSERM, UMR 1101, Brest (France)

    2015-05-18

    Respiratory and cardiac motion in PET/MR imaging leads to reduced quantitative and qualitative image accuracy. Correction methodologies involve the use of double gated acquisitions which lead to low signal-to-noise ratio (SNR) and to issues concerning the combination of cardiac and respiratory frames. The objective of this work is to use a generalized reconstruction by inversion of coupled systems (GRICS) approach, previously used for PET/MR respiratory motion correction, combined with a cardiac phase signal and a reconstruction incorporated PET motion correction approach in order to reconstruct motion free images from dual gated PET acquisitions. The GRICS method consists of formulating parallel MRI in the presence of patient motion as a coupled inverse problem. Its resolution, using a fixed-point method, allows the reconstructed image to be improved using a motion model constructed from the raw MR data and two respiratory belts. GRICS obtained respiratory displacements are interpolated using the cardiac phase derived from an ECG to model simultaneous cardiac and respiratory motion. Three different volunteer datasets (4DMR acquisitions) were used for evaluation. GATE was used to simulate 4DPET datasets corresponding to the acquired 4DMR images. Simulated data were subsequently binned using 16 cardiac phases (M1) vs diastole only (M2), in combination with 8 respiratory amplitude gates. Respiratory and cardiac motion corrected PET images using either M1 or M2 were compared to respiratory only corrected images and evaluated in terms of SNR and contrast improvement. Significant visual improvements were obtained when correcting simultaneously for respiratory and cardiac motion (using 16 cardiac phase or diastole only) compared to respiratory motion only compensation. Results were confirmed by an associated increased SNR and contrast. Results indicate that using GRICS is an efficient tool for respiratory and cardiac motion correction in dual gated PET/MR imaging.

  18. Correlation between the respiratory waveform measured using a respiratory sensor and 3D tumor motion in gated radiotherapy

    International Nuclear Information System (INIS)

    Tsunashima, Yoshikazu; Sakae, Takeji; Shioyama, Yoshiyuki; Kagei, Kenji; Terunuma, Toshiyuki; Nohtomi, Akihiro; Akine, Yasuyuki

    2004-01-01

    Purpose: The purpose of this study is to investigate the correlation between the respiratory waveform measured using a respiratory sensor and three-dimensional (3D) tumor motion. Methods and materials: A laser displacement sensor (LDS: KEYENCE LB-300) that measures distance using infrared light was used as the respiratory sensor. This was placed such that the focus was in an area around the patient's navel. When the distance from the LDS to the body surface changes as the patient breathes, the displacement is detected as a respiratory waveform. To obtain the 3D tumor motion, a biplane digital radiography unit was used. For the tumor in the lung, liver, and esophagus of 26 patients, the waveform was compared with the 3D tumor motion. The relationship between the respiratory waveform and the 3D tumor motion was analyzed by means of the Fourier transform and a cross-correlation function. Results: The respiratory waveform cycle agreed with that of the cranial-caudal and dorsal-ventral tumor motion. A phase shift observed between the respiratory waveform and the 3D tumor motion was principally in the range 0.0 to 0.3 s, regardless of the organ being measured, which means that the respiratory waveform does not always express the 3D tumor motion with fidelity. For this reason, the standard deviation of the tumor position in the expiration phase, as indicated by the respiratory waveform, was derived, which should be helpful in suggesting the internal margin required in the case of respiratory gated radiotherapy. Conclusion: Although obtained from only a few breathing cycles for each patient, the correlation between the respiratory waveform and the 3D tumor motion was evident in this study. If this relationship is analyzed carefully and an internal margin is applied, the accuracy and convenience of respiratory gated radiotherapy could be improved by use of the respiratory sensor.Thus, it is expected that this procedure will come into wider use

  19. Comparison of respiratory surrogates for gated lung radiotherapy without internal fiducials

    International Nuclear Information System (INIS)

    Korreman, S.; Mostafavi, H.; Le, Q.T.; Boyer, A.

    2006-01-01

    An investigation was carried out to compare the ability of two respiratory surrogates to mimic actual lung tumor motion during audio coaching. The investigation employed video clips acquired after patients had had fiducial markers implanted in lung tumors to be used for image-guided stereoscopic radiotherapy. The positions of the markers in the clips were measured within the video frames and used as the standard for tumor volume motion. An external marker was tracked optically during the fluoroscopic acquisitions. An image correlation technique was developed to compute a gating signal from the fluoroscopic images. The correlation gating trace was similar to the optical gating trace in the phase regions of the respiratory cycle used for gating. A cross correlation analysis and comparison of the external optical marker gating with internal fluoroscopic gating was performed. The fluoroscopic image correlation surrogate was found to be superior to the external optical surrogate in the AP-views in four out of six cases. In one of the remaining two cases, the two surrogates performed comparably, while in the last case, the external fiducial trace performed best. It was concluded that fluoroscopic gating based on correlation of native image features in the fluoroscopic images will be adequate for respiratory gating

  20. Comparison of respiratory surrogates for gated lung radiotherapy without internal fiducials

    Energy Technology Data Exchange (ETDEWEB)

    Korreman, S. [Rigshospitalet, Copenhagen (Denmark). Dept. of Radiation Oncology; Mostafavi, H. [Varian Medical Systems, Mountain View, CA (United States). Gintzon Technology Center; Le, Q.T.; Boyer, A. [Stanford Univ. School of Medicine, CA (United States). Dept. of Radiation Oncology

    2006-09-15

    An investigation was carried out to compare the ability of two respiratory surrogates to mimic actual lung tumor motion during audio coaching. The investigation employed video clips acquired after patients had had fiducial markers implanted in lung tumors to be used for image-guided stereoscopic radiotherapy. The positions of the markers in the clips were measured within the video frames and used as the standard for tumor volume motion. An external marker was tracked optically during the fluoroscopic acquisitions. An image correlation technique was developed to compute a gating signal from the fluoroscopic images. The correlation gating trace was similar to the optical gating trace in the phase regions of the respiratory cycle used for gating. A cross correlation analysis and comparison of the external optical marker gating with internal fluoroscopic gating was performed. The fluoroscopic image correlation surrogate was found to be superior to the external optical surrogate in the AP-views in four out of six cases. In one of the remaining two cases, the two surrogates performed comparably, while in the last case, the external fiducial trace performed best. It was concluded that fluoroscopic gating based on correlation of native image features in the fluoroscopic images will be adequate for respiratory gating.

  1. An evaluation of gating window size, delivery method, and composite field dosimetry of respiratory-gated IMRT

    International Nuclear Information System (INIS)

    Hugo, Geoffrey D.; Agazaryan, Nzhde; Solberg, Timothy D.

    2002-01-01

    A respiratory gating system has been developed based on a commercial patient positioning system. The purpose of this study is to investigate the ability of the gating system to reproduce normal, nongated IMRT operation and to quantify the errors produced by delivering a nongated IMRT treatment onto a moving target. A moving phantom capable of simultaneous two-dimensional motion was built, and an analytical liver motion function was used to drive the phantom. Studies were performed to assess the effect of gating window size and choice of delivery method (segmented and dynamic multileaf collimation). Additionally, two multiple field IMRT cases were delivered to quantify the error in gated and nongated IMRT with motion. Dosimetric error between nonmoving and moving deliveries is related to gating window size. By reducing the window size, the error can be reduced. Delivery error can be reduced for both dynamic and segmented delivery with gating. For the implementation of dynamic IMRT delivery in this study, dynamic delivery was found to generate larger delivery errors than segmented delivery in most cases studied. For multiple field IMRT delivery, the largest errors were generated in regions where high field modulation was present parallel to the axis of motion. Gating was found to reduce these large errors to clinically acceptable levels

  2. Organ motion study and dosimetric impact of respiratory gating radiotherapy for esophageal cancer

    International Nuclear Information System (INIS)

    Lorchel, F.

    2007-04-01

    Chemoradiotherapy is now the standard treatment for locally advanced or inoperable esophageal carcinoma. In this indication, conformal radiotherapy is generally used. However, prognosis remains poor for these patients. Respiratory gating radiotherapy can decrease healthy tissues irradiation and allows escalation dose in lung, liver and breast cancer. In order to improve radiotherapy technique, we propose to study the feasibility of respiratory gating for esophageal cancer. We will study the respiratory motions of esophageal cancer to optimize target volume delineation, especially the internal margin (I.M.). We will test the correlation between tumour and chest wall displacements to prove that esophageal cancer motions are induced by respiration. This is essential before using free breathing respiratory gating systems. We will work out the dosimetric impact of respiratory gating using various dosimetric analysis parameters. We will compare dosimetric plans at end expiration, end inspiration and deep inspiration with dosimetric plan in free-breathing condition. This will allow us to establish the best respiratory phase to irradiate for each gating system. This dosimetric study will be completed with linear quadratic equivalent uniform dose (E.U.D.) calculation for each volume of interest. Previously, we will do a theoretical study of histogram dose volume gradation to point up its use. (author)

  3. Respiratory gating based on internal electromagnetic motion monitoring during stereotactic liver radiation therapy: First results.

    Science.gov (United States)

    Poulsen, Per Rugaard; Worm, Esben Schjødt; Hansen, Rune; Larsen, Lars Peter; Grau, Cai; Høyer, Morten

    2015-01-01

    Intrafraction motion may compromise the target dose in stereotactic body radiation therapy (SBRT) of tumors in the liver. Respiratory gating can improve the treatment delivery, but gating based on an external surrogate signal may be inaccurate. This is the first paper reporting on respiratory gating based on internal electromagnetic monitoring during liver SBRT. Two patients with solitary liver metastases were treated with respiratory-gated SBRT guided by three implanted electromagnetic transponders. The treatment was delivered in end-exhale with beam-on when the centroid of the three transponders deviated less than 3 mm [left-right (LR) and anterior-posterior (AP) directions] and 4mm [cranio-caudal (CC)] from the planned position. For each treatment fraction, log files were used to determine the transponder motion during beam-on in the actual gated treatments and in simulated treatments without gating. The motion was used to reconstruct the dose to the clinical target volume (CTV) with and without gating. The reduction in D95 (minimum dose to 95% of the CTV) relative to the plan was calculated for both treatment courses. With gating the maximum course mean (standard deviation) geometrical error in any direction was 1.2 mm (1.8 mm). Without gating the course mean error would mainly increase for Patient 1 [to -2.8 mm (1.6 mm) (LR), 7.1 mm (5.8 mm) (CC), -2.6 mm (2.8mm) (AP)] due to a large systematic cranial baseline drift at each fraction. The errors without gating increased only slightly for Patient 2. The reduction in CTV D95 was 0.5% (gating) and 12.1% (non-gating) for Patient 1 and 0.3% (gating) and 1.7% (non-gating) for Patient 2. The mean duty cycle was 55%. Respiratory gating based on internal electromagnetic motion monitoring was performed for two liver SBRT patients. The gating added robustness to the dose delivery and ensured a high CTV dose even in the presence of large intrafraction motion.

  4. Dual cardiac-respiratory gated PET: implementation and results from a feasibility study

    International Nuclear Information System (INIS)

    Martinez-Moeller, Axel; Zikic, Darko; Navab, Nassir; Botnar, Rene M.; Bundschuh, Ralph A.; Ziegler, Sibylle I.; Schwaiger, Markus; Nekolla, Stephan G.; Howe, William

    2007-01-01

    Spatial resolution in myocardial imaging is impaired by both cardiac and respiratory motion owing to motional blurring. We investigated the feasibility of a dual cardiac-respiratory gated positron emission tomography (PET) acquisition using a clinical PET/computer tomography (CT) scanner. We describe its implementation and present results on the respiratory motion observed. The correlation between diaphragmatic excursion measured by real-time magnetic resonance imaging (MRI) and the expansion of the chest measured with an elastic belt was studied in six subjects. PET list mode acquisitions were then performed in 12 patients, six of them injected with 13 N-ammonia and six with 18 F-FDG. In parallel, the ECG and respiratory signals of the patients were recorded and the list mode file correspondingly sorted using a dual gated approach. Respiratory motion of the heart was quantified by measuring the displacement between the inspiratory and expiratory images in the diastolic phase by means of intensity-based non-rigid image registration. The correlation between diaphragmatic excursion and expansion of the chest was excellent (R 2 = 0.91), validating the ability of the elastic belt to provide an adequate respiratory trigger. Respiratory signals corresponding to the chest expansion showed a large inter-patient variability, requiring adapted algorithms in order to define suitable respiratory gates. Dual gated PET series were successfully acquired for both groups of patients, showing better resolved myocardial walls. The average respiratory motion of the heart measured by PET was 4.8 mm, with its largest component in the craniocaudal direction. Moreover, a deformation of the heart with respiration was observed, with the inferior wall moving significantly more than the anterior. Dual gated cardiac PET studies were performed successfully and showed better resolved myocardial walls as compared with ungated acquisitions. The respiratory motion of the heart presented a

  5. External radioactive markers for PET data-driven respiratory gating in positron emission tomography.

    Science.gov (United States)

    Büther, Florian; Ernst, Iris; Hamill, James; Eich, Hans T; Schober, Otmar; Schäfers, Michael; Schäfers, Klaus P

    2013-04-01

    Respiratory gating is an established approach to overcoming respiration-induced image artefacts in PET. Of special interest in this respect are raw PET data-driven gating methods which do not require additional hardware to acquire respiratory signals during the scan. However, these methods rely heavily on the quality of the acquired PET data (statistical properties, data contrast, etc.). We therefore combined external radioactive markers with data-driven respiratory gating in PET/CT. The feasibility and accuracy of this approach was studied for [(18)F]FDG PET/CT imaging in patients with malignant liver and lung lesions. PET data from 30 patients with abdominal or thoracic [(18)F]FDG-positive lesions (primary tumours or metastases) were included in this prospective study. The patients underwent a 10-min list-mode PET scan with a single bed position following a standard clinical whole-body [(18)F]FDG PET/CT scan. During this scan, one to three radioactive point sources (either (22)Na or (18)F, 50-100 kBq) in a dedicated holder were attached the patient's abdomen. The list mode data acquired were retrospectively analysed for respiratory signals using established data-driven gating approaches and additionally by tracking the motion of the point sources in sinogram space. Gated reconstructions were examined qualitatively, in terms of the amount of respiratory displacement and in respect of changes in local image intensity in the gated images. The presence of the external markers did not affect whole-body PET/CT image quality. Tracking of the markers led to characteristic respiratory curves in all patients. Applying these curves for gated reconstructions resulted in images in which motion was well resolved. Quantitatively, the performance of the external marker-based approach was similar to that of the best intrinsic data-driven methods. Overall, the gain in measured tumour uptake from the nongated to the gated images indicating successful removal of respiratory motion

  6. Dosimetric evaluation of the interplay effect in respiratory-gated RapidArc radiation therapy

    International Nuclear Information System (INIS)

    Riley, Craig; Yang, Yong; Li, Tianfang; Zhang, Yongqian; Heron, Dwight E.; Huq, M. Saiful

    2014-01-01

    Purpose: Volumetric modulated arc therapy (VMAT) with gating capability has had increasing adoption in many clinics in the United States. In this new technique, dose rate, gantry rotation speed, and the leaf motion speed of multileaf collimators (MLCs) are modulated dynamically during gated beam delivery to achieve highly conformal dose coverage of the target and normal tissue sparing. Compared with the traditional gated intensity-modulated radiation therapy technique, this complicated beam delivery technique may result in larger dose errors due to the intrafraction tumor motion. The purpose of this work is to evaluate the dosimetric influence of the interplay effect for the respiration-gated VMAT technique (RapidArc, Varian Medical Systems, Palo Alto, CA). Our work consisted of two parts: (1) Investigate the interplay effect for different target residual errors during gated RapidArc delivery using a one-dimensional moving phantom capable of producing stable sinusoidal movement; (2) Evaluate the dosimetric influence in ten clinical patients’ treatment plans using a moving phantom driven with a patient-specific respiratory curve. Methods: For the first part of this study, four plans were created with a spherical target for varying residual motion of 0.25, 0.5, 0.75, and 1.0 cm. Appropriate gating windows were applied for each. The dosimetric effect was evaluated using EDR2 film by comparing the gated delivery with static delivery. For the second part of the project, ten gated lung stereotactic body radiotherapy cases were selected and reoptimized to be delivered by the gated RapidArc technique. These plans were delivered to a phantom, and again the gated treatments were compared to static deliveries by the same methods. Results: For regular sinusoidal motion, the dose delivered to the target was not substantially affected by the gating windows when evaluated with the gamma statistics, suggesting the interplay effect has a small role in respiratory-gated Rapid

  7. Dosimetric evaluation of the interplay effect in respiratory-gated RapidArc radiation therapy.

    Science.gov (United States)

    Riley, Craig; Yang, Yong; Li, Tianfang; Zhang, Yongqian; Heron, Dwight E; Huq, M Saiful

    2014-01-01

    Volumetric modulated arc therapy (VMAT) with gating capability has had increasing adoption in many clinics in the United States. In this new technique, dose rate, gantry rotation speed, and the leaf motion speed of multileaf collimators (MLCs) are modulated dynamically during gated beam delivery to achieve highly conformal dose coverage of the target and normal tissue sparing. Compared with the traditional gated intensity-modulated radiation therapy technique, this complicated beam delivery technique may result in larger dose errors due to the intrafraction tumor motion. The purpose of this work is to evaluate the dosimetric influence of the interplay effect for the respiration-gated VMAT technique (RapidArc, Varian Medical Systems, Palo Alto, CA). Our work consisted of two parts: (1) Investigate the interplay effect for different target residual errors during gated RapidArc delivery using a one-dimensional moving phantom capable of producing stable sinusoidal movement; (2) Evaluate the dosimetric influence in ten clinical patients' treatment plans using a moving phantom driven with a patient-specific respiratory curve. For the first part of this study, four plans were created with a spherical target for varying residual motion of 0.25, 0.5, 0.75, and 1.0 cm. Appropriate gating windows were applied for each. The dosimetric effect was evaluated using EDR2 film by comparing the gated delivery with static delivery. For the second part of the project, ten gated lung stereotactic body radiotherapy cases were selected and reoptimized to be delivered by the gated RapidArc technique. These plans were delivered to a phantom, and again the gated treatments were compared to static deliveries by the same methods. For regular sinusoidal motion, the dose delivered to the target was not substantially affected by the gating windows when evaluated with the gamma statistics, suggesting the interplay effect has a small role in respiratory-gated RapidArc therapy. Varied results were

  8. Respiratory gating of cardiac PET data in list-mode acquisition

    International Nuclear Information System (INIS)

    Livieratos, Lefteris; Rajappan, Kim; Camici, Paolo G.; Stegger, Lars; Schafers, Klaus; Bailey, Dale L.

    2006-01-01

    Respiratory motion has been identified as a source of artefacts in most medical imaging modalities. This paper reports on respiratory gating as a means to eliminate motion-related inaccuracies in PET imaging. Respiratory gating was implemented in list mode with physiological signal recorded every millisecond together with the PET data. Respiration was monitored with an inductive respiration monitor using an elasticised belt around the patient's chest. Simultaneous ECG gating can be maintained independently by encoding ECG trigger signal into the list-mode data. Respiratory gating is performed in an off-line workstation with gating parameters defined retrospectively. The technique was applied on a preliminary set of patient data with C 15 O. Motion was visually observed in the cine displays of the sagittal and coronal views of the reconstructed respiratory gated images. Significant changes in the cranial-caudal position of the heart could be observed. The centroid of the cardiac blood pool showed an excursion of 4.5-16.5 mm (mean 8.5±4.8 mm) in the cranial-caudal direction, with more limited excursion of 1.1-7.0 mm (mean 2.5±2.2 mm) in the horizontal direction and 1.3-3.7 mm (mean 2.4±0.9 mm) in the vertical direction. These preliminary data show that the extent of motion involved in respiration is comparable to myocardial wall thickness, and respiratory gating may be considered in order to reduce this effect in the reconstructed images. (orig.)

  9. 3-D cardiac MRI in free-breathing newborns and infants: when is respiratory gating necessary?

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Achim [University Hospital of Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); University Hospital of Tuebingen, Department of Diagnostic and Interventional Neuroradiology, Tuebingen (Germany); Krumm, Patrick; Schaefer, Juergen F.; Kramer, Ulrich [University Hospital of Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Hornung, Andreas; Sieverding, Ludger [University Hospital of Tuebingen, Department of Pediatric Cardiology, Tuebingen (Germany)

    2015-09-15

    Newborns and small infants have shallow breathing. To suggest criteria for when respiratory gating is necessary during cardiac MRI in newborns and infants. One-hundred ten data sets of newborns and infants with (n = 92, mean age: 1.9 ± 1.7 [SD] years) and without (n = 18, mean age: 1.6 ± 1.8 [SD] years) navigator gating were analysed retrospectively. The respiratory motion of the right hemidiaphragm was recorded and correlated to age, weight, body surface area and qualitative image quality on a 4-point score. Quantitative image quality assessment was performed (sharpness of the delineation of the ventricular septal wall) as well as a matched-pair comparison between navigator-gated and non-gated data sets. No significant differences were found in overall image quality or in the sharpness of the ventricular septal wall between gated and non-gated scans. A navigator acceptance of >80% was frequently found in patients ages <12 months, body surface area <0.40 m{sup 2}, body weight <10 kg and a size of <80 cm. Sequences without respiratory gating may be used in newborns and small infants, in particular if age <12 months, body surface area <0.40 m{sup 2}, body weight <10 kg and height <80 cm. (orig.)

  10. Respiratory gating during stereotactic body radiotherapy for lung cancer reduces tumor position variability.

    Science.gov (United States)

    Saito, Tetsuo; Matsuyama, Tomohiko; Toya, Ryo; Fukugawa, Yoshiyuki; Toyofuku, Takamasa; Semba, Akiko; Oya, Natsuo

    2014-01-01

    We evaluated the effects of respiratory gating on treatment accuracy in lung cancer patients undergoing lung stereotactic body radiotherapy by using electronic portal imaging device (EPID) images. Our study population consisted of 30 lung cancer patients treated with stereotactic body radiotherapy (48 Gy/4 fractions/4 to 9 days). Of these, 14 were treated with- (group A) and 16 without gating (group B); typically the patients whose tumors showed three-dimensional respiratory motion ≧5 mm were selected for gating. Tumor respiratory motion was estimated using four-dimensional computed tomography images acquired during treatment simulation. Tumor position variability during all treatment sessions was assessed by measuring the standard deviation (SD) and range of tumor displacement on EPID images. The two groups were compared for tumor respiratory motion and position variability using the Mann-Whitney U test. The median three-dimensional tumor motion during simulation was greater in group A than group B (9 mm, range 3-30 mm vs. 2 mm, range 0-4 mm; psimulation, tumor position variability in the EPID images was low and comparable to patients treated without gating. This demonstrates the benefit of respiratory gating.

  11. Technical and dosimetric aspects of respiratory gating using a pressure-sensor motion monitoring system

    International Nuclear Information System (INIS)

    Li, X. Allen; Stepaniak, Christopher; Gore, Elizabeth

    2006-01-01

    This work introduces a gating technique that uses 4DCT to determine gating parameters and to plan gated treatment, and employs a Siemens linear accelerator to deliver the gated treatment. Because of technology incompatibility, the 4DCT scanner (LightSpeed, GE) and the Siemens accelerator require two different motion-monitoring systems. The motion monitoring system (AZ-773V, Anzai Med.) used for the gated delivery utilizes a pressure sensor to detect the external respiratory motion (pressure change) in real time. Another system (RPM, Varian) used for the 4DCT scanner (LightSpeed, GE) is based on an infrared camera to detect motion of external markers. These two motion monitoring systems (RPM and Anzai systems) were found to correlate well with each other. The depth doses and profile measured for gated delivery (with a duty cycle of 25% or 50%) were found to agree within 1.0% with those measured for ungated delivery, indicating that gating did not significantly alter beam characteristics. The measurement verified also that the MU linearity and beam output remained unchanged (within 0.3%). A practical method of using 4DCT to plan a gated treatment was developed. The duty cycle for either phase or amplitude gating can be determined based on 4DCT with consideration of set-up error and delivery efficiency. The close-loop measurement involving the entire gating process (imaging, planning, and delivery) showed that the measured isodose distributions agreed with those intended, validating the accuracy and reliability of the gating technique. Based these observations, we conclude that the gating technique introduced in this work, integrating Siemens linear accelerator and Anzai pressure sensor device with GE/Varian RPM 4DCT, is reliable and effective, and it can be used clinically to account for respiratory motion during radiation therapy

  12. Respiratory lung motion analysis using a nonlinear motion correction technique for respiratory-gated lung perfusion SPECT images

    International Nuclear Information System (INIS)

    Ue, Hidenori; Haneishi, Hideaki; Iwanaga, Hideyuki; Suga, Kazuyoshi

    2007-01-01

    This study evaluated the respiratory motion of lungs using a nonlinear motion correction technique for respiratory-gated single photon emission computed tomography (SPECT) images. The motion correction technique corrects the respiratory motion of the lungs nonlinearly between two-phase images obtained by respiratory-gated SPECT. The displacement vectors resulting from respiration can be computed at every location of the lungs. Respiratory lung motion analysis is carried out by calculating the mean value of the body axis component of the displacement vector in each of the 12 small regions into which the lungs were divided. In order to enable inter-patient comparison, the 12 mean values were normalized by the length of the lung region along the direction of the body axis. This method was applied to 25 Technetium (Tc)-99m-macroaggregated albumin (MAA) perfusion SPECT images, and motion analysis results were compared with the diagnostic results. It was confirmed that the respiratory lung motion reflects the ventilation function. A statistically significant difference in the amount of the respiratory lung motion was observed between the obstructive pulmonary diseases and other conditions, based on an unpaired Student's t test (P<0.0001). A difference in the motion between normal lungs and lungs with a ventilation obstruction was detected by the proposed method. This method is effective for evaluating obstructive pulmonary diseases such as pulmonary emphysema and diffuse panbronchiolitis. (author)

  13. SU-E-J-159: Analysis of Total Imaging Uncertainty in Respiratory-Gated Radiotherapy

    International Nuclear Information System (INIS)

    Suzuki, J; Okuda, T; Sakaino, S; Yokota, N

    2015-01-01

    Purpose: In respiratory-gated radiotherapy, the gating phase during treatment delivery needs to coincide with the corresponding phase determined during the treatment plan. However, because radiotherapy is performed based on the image obtained for the treatment plan, the time delay, motion artifact, volume effect, and resolution in the images are uncertain. Thus, imaging uncertainty is the most basic factor that affects the localization accuracy. Therefore, these uncertainties should be analyzed. This study aims to analyze the total imaging uncertainty in respiratory-gated radiotherapy. Methods: Two factors of imaging uncertainties related to respiratory-gated radiotherapy were analyzed. First, CT image was used to determine the target volume and 4D treatment planning for the Varian Realtime Position Management (RPM) system. Second, an X-ray image was acquired for image-guided radiotherapy (IGRT) for the BrainLAB ExacTrac system. These factors were measured using a respiratory gating phantom. The conditions applied during phantom operation were as follows: respiratory wave form, sine curve; respiratory cycle, 4 s; phantom target motion amplitude, 10, 20, and 29 mm (which is maximum phantom longitudinal motion). The target and cylindrical marker implanted in the phantom coverage of the CT images was measured and compared with the theoretically calculated coverage from the phantom motion. The theoretical position of the cylindrical marker implanted in the phantom was compared with that acquired from the X-ray image. The total imaging uncertainty was analyzed from these two factors. Results: In the CT image, the uncertainty between the target and cylindrical marker’s actual coverage and the coverage of CT images was 1.19 mm and 2.50mm, respectively. In the Xray image, the uncertainty was 0.39 mm. The total imaging uncertainty from the two factors was 1.62mm. Conclusion: The total imaging uncertainty in respiratory-gated radiotherapy was clinically acceptable. However

  14. SU-E-J-159: Analysis of Total Imaging Uncertainty in Respiratory-Gated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, J; Okuda, T [Toyota memorial hospital, Toyota, Aichi (Japan); Sakaino, S; Yokota, N [Suzukake central hospital, Hamamatsu, Shizuoka (Japan)

    2015-06-15

    Purpose: In respiratory-gated radiotherapy, the gating phase during treatment delivery needs to coincide with the corresponding phase determined during the treatment plan. However, because radiotherapy is performed based on the image obtained for the treatment plan, the time delay, motion artifact, volume effect, and resolution in the images are uncertain. Thus, imaging uncertainty is the most basic factor that affects the localization accuracy. Therefore, these uncertainties should be analyzed. This study aims to analyze the total imaging uncertainty in respiratory-gated radiotherapy. Methods: Two factors of imaging uncertainties related to respiratory-gated radiotherapy were analyzed. First, CT image was used to determine the target volume and 4D treatment planning for the Varian Realtime Position Management (RPM) system. Second, an X-ray image was acquired for image-guided radiotherapy (IGRT) for the BrainLAB ExacTrac system. These factors were measured using a respiratory gating phantom. The conditions applied during phantom operation were as follows: respiratory wave form, sine curve; respiratory cycle, 4 s; phantom target motion amplitude, 10, 20, and 29 mm (which is maximum phantom longitudinal motion). The target and cylindrical marker implanted in the phantom coverage of the CT images was measured and compared with the theoretically calculated coverage from the phantom motion. The theoretical position of the cylindrical marker implanted in the phantom was compared with that acquired from the X-ray image. The total imaging uncertainty was analyzed from these two factors. Results: In the CT image, the uncertainty between the target and cylindrical marker’s actual coverage and the coverage of CT images was 1.19 mm and 2.50mm, respectively. In the Xray image, the uncertainty was 0.39 mm. The total imaging uncertainty from the two factors was 1.62mm. Conclusion: The total imaging uncertainty in respiratory-gated radiotherapy was clinically acceptable. However

  15. SU-E-J-45: Design and Study of An In-House Respiratory Gating Phantom Platform for Gated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Senthilkumar, S [Madurai Medical College ' Govt. Rajaji Hospital, Madurai (India)

    2014-06-01

    Purpose: The main purpose of this work was to develop an in-house low cost respiratory motion phantom platform for testing the accuracy of the gated radiotherapy system and analyze the dosimetric difference during gated radiotherapy. Methods: An in-house respiratory motion platform(RMP) was designed and constructed for testing the targeting accuracy of respiratory tracking system. The RMP consist of acrylic Chest Wall Platform, 2 DC motors, 4 IR sensors, speed controller circuit, 2 LED and 2 moving rods inside the RMP. The velocity of the movement can be varied from 0 to 30 cycles per minute. The platform mounted to a base using precision linear bearings. The base and platform are made of clear, 15mm thick polycarbonate plastic and the linear ball bearings are oriented to restrict the platform to a movement of approximately 50mm up and down with very little friction. Results: The targeting accuracy of the respiratory tracking system was evaluated using phantom with and without respiratory movement with varied amplitude. We have found the 5% dose difference to the PTV during the movement in comparison with stable PTV. The RMP can perform sinusoidal motion in 1D with fixed peak to peak motion of 5 to 50mm and cycle interval from 2 to 6 seconds. The RMP was designed to be able to simulate the gross anatomical anterior posterior motion attributable to respiration-induced motion of the thoracic region. Conclusion: The unique RMP simulates breathing providing the means to create a comprehensive program for commissioning, training, quality assurance and dose verification of gated radiotherapy treatments. Create the anterior/posterior movement of a target over a 5 to 50 mm distance to replicate tumor movement. The targeting error of the respiratory tracking system is less than 1.0 mm which shows suitable for clinical treatment with highly performance.

  16. SU-E-J-45: Design and Study of An In-House Respiratory Gating Phantom Platform for Gated Radiotherapy

    International Nuclear Information System (INIS)

    Senthilkumar, S

    2014-01-01

    Purpose: The main purpose of this work was to develop an in-house low cost respiratory motion phantom platform for testing the accuracy of the gated radiotherapy system and analyze the dosimetric difference during gated radiotherapy. Methods: An in-house respiratory motion platform(RMP) was designed and constructed for testing the targeting accuracy of respiratory tracking system. The RMP consist of acrylic Chest Wall Platform, 2 DC motors, 4 IR sensors, speed controller circuit, 2 LED and 2 moving rods inside the RMP. The velocity of the movement can be varied from 0 to 30 cycles per minute. The platform mounted to a base using precision linear bearings. The base and platform are made of clear, 15mm thick polycarbonate plastic and the linear ball bearings are oriented to restrict the platform to a movement of approximately 50mm up and down with very little friction. Results: The targeting accuracy of the respiratory tracking system was evaluated using phantom with and without respiratory movement with varied amplitude. We have found the 5% dose difference to the PTV during the movement in comparison with stable PTV. The RMP can perform sinusoidal motion in 1D with fixed peak to peak motion of 5 to 50mm and cycle interval from 2 to 6 seconds. The RMP was designed to be able to simulate the gross anatomical anterior posterior motion attributable to respiration-induced motion of the thoracic region. Conclusion: The unique RMP simulates breathing providing the means to create a comprehensive program for commissioning, training, quality assurance and dose verification of gated radiotherapy treatments. Create the anterior/posterior movement of a target over a 5 to 50 mm distance to replicate tumor movement. The targeting error of the respiratory tracking system is less than 1.0 mm which shows suitable for clinical treatment with highly performance

  17. Investigation of patient, tumour and treatment variables affecting residual motion for respiratory-gated radiotherapy

    International Nuclear Information System (INIS)

    George, R; Ramakrishnan, V; Siebers, J V; Chung, T D; Keall, P J

    2006-01-01

    Respiratory gating can reduce the apparent respiratory motion during imaging and treatment; however, residual motion within the gating window remains. Respiratory training can improve respiratory reproducibility and, therefore, the efficacy of respiratory-gated radiotherapy. This study was conducted to determine whether residual motion during respiratory gating is affected by patient, tumour or treatment characteristics. The specific aims of this study were to: (1) identify significant characteristics affecting residual motion, (2) investigate time trends of residual motion over a period of days (inter-session) and (3) investigate time trends of residual motion within the same day (intra-session). Twenty-four lung cancer patients were enrolled in an Institutional Review Board (IRB)-approved protocol. For approximately five sessions, 331 four-minute, respiratory motion traces were acquired with free breathing, audio instructions and audio-visual biofeedback for each patient. The residual motion was quantified by the standard deviation of the displacement within the gating window. The generalized linear model was used to obtain coefficients for each variable within the model and to evaluate the clinical and statistical significance. The statistical significance was determined by a p-value <0.05, while effect sizes of ≥0.1 cm (one standard deviation) were considered clinically significant. This data analysis was applied to patient, tumour and treatment variables. Inter- and intra-session variations were also investigated. The only variable that was significant for both inhale- and exhale-based gating was disease type. In addition, visual-training displacement, breathing type and Karnofsky performance status (KPS) values were significant for inhale-based gating, and dose-per-fraction was significant for exhale-based gating. Temporal respiratory variations within and between sessions were observed for individual patients. However inter- and intra-session analyses did

  18. Investigation of patient, tumour and treatment variables affecting residual motion for respiratory-gated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    George, R [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA (United States); Ramakrishnan, V [Department of Biostatistics, Virginia Commonwealth University, Richmond, VA (United States); Siebers, J V [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA (United States); Chung, T D [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA (United States); Keall, P J [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA (United States)

    2006-10-21

    Respiratory gating can reduce the apparent respiratory motion during imaging and treatment; however, residual motion within the gating window remains. Respiratory training can improve respiratory reproducibility and, therefore, the efficacy of respiratory-gated radiotherapy. This study was conducted to determine whether residual motion during respiratory gating is affected by patient, tumour or treatment characteristics. The specific aims of this study were to: (1) identify significant characteristics affecting residual motion, (2) investigate time trends of residual motion over a period of days (inter-session) and (3) investigate time trends of residual motion within the same day (intra-session). Twenty-four lung cancer patients were enrolled in an Institutional Review Board (IRB)-approved protocol. For approximately five sessions, 331 four-minute, respiratory motion traces were acquired with free breathing, audio instructions and audio-visual biofeedback for each patient. The residual motion was quantified by the standard deviation of the displacement within the gating window. The generalized linear model was used to obtain coefficients for each variable within the model and to evaluate the clinical and statistical significance. The statistical significance was determined by a p-value <0.05, while effect sizes of {>=}0.1 cm (one standard deviation) were considered clinically significant. This data analysis was applied to patient, tumour and treatment variables. Inter- and intra-session variations were also investigated. The only variable that was significant for both inhale- and exhale-based gating was disease type. In addition, visual-training displacement, breathing type and Karnofsky performance status (KPS) values were significant for inhale-based gating, and dose-per-fraction was significant for exhale-based gating. Temporal respiratory variations within and between sessions were observed for individual patients. However inter- and intra-session analyses did

  19. Prospective respiratory-gated micro-CT of free breathing rodents

    International Nuclear Information System (INIS)

    Ford, Nancy L.; Nikolov, Hristo N.; Norley, Chris J.D.; Thornton, Michael M.; Foster, Paula J.; Drangova, Maria; Holdsworth, David W.

    2005-01-01

    Microcomputed tomography (Micro-CT) has the potential to noninvasively image the structure of organs in rodent models with high spatial resolution and relatively short image acquisition times. However, motion artifacts associated with the normal respiratory motion of the animal may arise when imaging the abdomen or thorax. To reduce these artifacts and the accompanying loss of spatial resolution, we propose a prospective respiratory gating technique for use with anaesthetized, free-breathing rodents. A custom-made bed with an embedded pressure chamber was connected to a pressure transducer. Anaesthetized animals were placed in the prone position on the bed with their abdomens located over the chamber. During inspiration, the motion of the diaphragm caused an increase in the chamber pressure, which was converted into a voltage signal by the transducer. An output voltage was used to trigger image acquisition at any desired time point in the respiratory cycle. Digital radiographic images were acquired of anaesthetized, free-breathing rats with a digital radiographic system to correlate the respiratory wave form with respiration-induced organ motion. The respiratory wave form was monitored and recorded simultaneously with the x-ray radiation pulses, and an imaging window was defined, beginning at end expiration. Phantom experiments were performed to verify that the respiratory gating apparatus was triggering the micro-CT system. Attached to the distensible phantom were 100 μm diameter copper wires and the measured full width at half maximum was used to assess differences in image quality between respiratory-gated and ungated imaging protocols. This experiment allowed us to quantify the improvement in the spatial resolution, and the reduction of motion artifacts caused by moving structures, in the images resulting from respiratory-gated image acquisitions. The measured wire diameters were 0.135 mm for the stationary phantom image, 0.137 mm for the image gated at end

  20. In Vivo Respiratory-Gated Micro-CT Imaging in Small-Animal Oncology Models

    Directory of Open Access Journals (Sweden)

    Dawn Cavanaugh

    2004-01-01

    Full Text Available Micro-computed tomography (micro-CT is becoming an accepted research tool for the noninvasive examination of laboratory animals such as mice and rats, but to date, in vivo scanning has largely been limited to the evaluation of skeletal tissues. We use a commercially available micro-CT device to perform respiratory gated in vivo acquisitions suitable for thoracic imaging. The instrument is described, along with the scan protocol and animal preparation techniques. Preliminary results confirm that lung tumors as small as 1 mm in diameter are visible in vivo with these methods. Radiation dose was evaluated using several approaches, and was found to be approximately 0.15 Gy for this respiratory-gated micro-CT imaging protocol. The combination of high-resolution CT imaging and respiratory-gated acquisitions appears well-suited to serial in vivo scanning.

  1. Consideration of the accuracy by variation of respiration in real-time position management respiratory gating system

    International Nuclear Information System (INIS)

    Na, Jun Young; Kang, Tae Young; Beak, Geum Mun; Kwon, Gyeong Tae

    2013-01-01

    Respiratory Gated Radiation Therapy (RGRT) has been carried out using RPM (Real-time Position Management) Respiratory Gating System (version 1.7.5, varian, USA) in Asan Medical Center. This study was to analyze and evaluate the accuracy of Respiratory Gated Radiation Therapy (RGRT) according to variation of respiration. Making variation of respiration using Motion Phantom:QUASAR Programmable Respiratory Motion Phantom (Moudus Medical Device Inc. CANADA) able to adjust respiration pattern randomly was varying period, amplitude and baseline by analyze 50 patient's respiration of lung and liver cancer. One of the variations of respiration is baseline shift gradually downward per 0.01 cm, 0.03 cm, 0.05 cm. The other variation of respiration is baseline shift accidently downward per 0.2 cm, 0.4 cm, 0.6 cm, 0.8 cm. Experiments were performed in the same way that is used RPM Respiratory Gating System (phase gating, usually 30-70% gating) in Asan Medical Center. It was all exposed radiation under one of the conditions of baseline shift gradually downward per 0.01 cm, 0.03 cm, 0.05 cm. Under the other condition of baseline shift accidently downward per 0.2 cm, 0.4 cm, 0.6 cm, 0.8 cm equally radiation was exposed. The variations of baseline shifts didn't accurately reflect on phase gating in RPM Respiratory Gating System. This inexactitude makes serious uncertainty in Respiratory Gated Radiation Therapy. So, Must be stabilized breathing of patient before conducting Respiratory Gated Radiation Therapy. also must be monitored breathing of patient in the middle of treatment. If you observe considerable changes of breathing when conducting Respiratory Gated Radiation Therapy. Stopping treatment immediately and then must be need to recheck treatment site using fluoroscopy. If patient's respiration rechecked using fluoroscopy restabilize, it is possible to restart Respiratory Gated Radiation Therapy

  2. Extraction of the respiratory signal from small-animal CT projections for a retrospective gating method

    International Nuclear Information System (INIS)

    ChavarrIas, C; Vaquero, J J; Sisniega, A; RodrIguez-Ruano, A; Soto-Montenegro, M L; GarcIa-Barreno, P; Desco, M

    2008-01-01

    We propose a retrospective respiratory gating algorithm to generate dynamic CT studies. To this end, we compared three different methods of extracting the respiratory signal from the projections of small-animal cone-beam computed tomography (CBCT) scanners. Given a set of frames acquired from a certain axial angle, subtraction of their average image from each individual frame produces a set of difference images. Pixels in these images have positive or negative values (according to the respiratory phase) in those areas where there is lung movement. The respiratory signals were extracted by analysing the shape of the histogram of these difference images: we calculated the first four central and non-central moments. However, only odd-order moments produced the desired breathing signal, as the even-order moments lacked information about the phase. Each of these curves was compared to a reference signal recorded by means of a pneumatic pillow. Given the similar correlation coefficients yielded by all of them, we selected the mean to implement our retrospective protocol. Respiratory phase bins were separated, reconstructed independently and included in a dynamic sequence, suitable for cine playback. We validated our method in five adult rat studies by comparing profiles drawn across the diaphragm dome, with and without retrospective respiratory gating. Results showed a sharper transition in the gated reconstruction, with an average slope improvement of 60.7%

  3. Extraction of the respiratory signal from small-animal CT projections for a retrospective gating method

    Energy Technology Data Exchange (ETDEWEB)

    ChavarrIas, C; Vaquero, J J; Sisniega, A; RodrIguez-Ruano, A; Soto-Montenegro, M L; GarcIa-Barreno, P; Desco, M [Unidad de Medicina y CirugIa Experimental, Hospital General Universitario Gregorio Maranon, Anexo PsiquiatrIa, 1 Planta. C/Ibiza, 43. Madrid 28007 (Spain)

    2008-09-07

    We propose a retrospective respiratory gating algorithm to generate dynamic CT studies. To this end, we compared three different methods of extracting the respiratory signal from the projections of small-animal cone-beam computed tomography (CBCT) scanners. Given a set of frames acquired from a certain axial angle, subtraction of their average image from each individual frame produces a set of difference images. Pixels in these images have positive or negative values (according to the respiratory phase) in those areas where there is lung movement. The respiratory signals were extracted by analysing the shape of the histogram of these difference images: we calculated the first four central and non-central moments. However, only odd-order moments produced the desired breathing signal, as the even-order moments lacked information about the phase. Each of these curves was compared to a reference signal recorded by means of a pneumatic pillow. Given the similar correlation coefficients yielded by all of them, we selected the mean to implement our retrospective protocol. Respiratory phase bins were separated, reconstructed independently and included in a dynamic sequence, suitable for cine playback. We validated our method in five adult rat studies by comparing profiles drawn across the diaphragm dome, with and without retrospective respiratory gating. Results showed a sharper transition in the gated reconstruction, with an average slope improvement of 60.7%.

  4. Audiovisual biofeedback improves image quality and reduces scan time for respiratory-gated 3D MRI

    Science.gov (United States)

    Lee, D.; Greer, P. B.; Arm, J.; Keall, P.; Kim, T.

    2014-03-01

    The purpose of this study was to test the hypothesis that audiovisual (AV) biofeedback can improve image quality and reduce scan time for respiratory-gated 3D thoracic MRI. For five healthy human subjects respiratory motion guidance in MR scans was provided using an AV biofeedback system, utilizing real-time respiratory motion signals. To investigate the improvement of respiratory-gated 3D MR images between free breathing (FB) and AV biofeedback (AV), each subject underwent two imaging sessions. Respiratory-related motion artifacts and imaging time were qualitatively evaluated in addition to the reproducibility of external (abdominal) motion. In the results, 3D MR images in AV biofeedback showed more anatomic information such as a clear distinction of diaphragm, lung lobes and sharper organ boundaries. The scan time was reduced from 401±215 s in FB to 334±94 s in AV (p-value 0.36). The root mean square variation of the displacement and period of the abdominal motion was reduced from 0.4±0.22 cm and 2.8±2.5 s in FB to 0.1±0.15 cm and 0.9±1.3 s in AV (p-value of displacement audiovisual biofeedback improves image quality and reduces scan time for respiratory-gated 3D MRI. These results suggest that AV biofeedback has the potential to be a useful motion management tool in medical imaging and radiation therapy procedures.

  5. Evaluation and reduction of respiratory motion artifacts in small animal SPECT with GATE

    International Nuclear Information System (INIS)

    Lee, C.-L.; Park, S.-J.; Kim, H.-J.

    2015-01-01

    The degradation of image quality caused by respiration is a major impediment to accurate lesion detection in single photon emission computed tomography (SPECT) imaging. This study was performed to evaluate the effects of lung motion on image quantification. A small animal SPECT system with NaI(Tl) was modeled in the Geant4 application for tomographic emission (GATE) simulation for a lung lesion using a 4D mouse whole-body phantom. SPECT images were obtained using 120 projection views acquired from 0 o to 360 o with a 3 o step. Slices were reconstructed using ordered subsets expectation maximization (OS-EM) without attenuation correction with five iterations and four subsets. Image quality was compared between the static mode without respiratory motion, and dynamic mode with respiratory motion in terms of spatial resolution was measured by the full width at half maximum (FWHM), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). The FWHM of the non-gated image and the respiratory gated image were also compared. Spatial resolution improved as activity increased and lesion diameter decreased in the static and dynamic modes. The SNR and CNR increased significantly as lesion activity increased and lesion diameter decreased. Our results show that respiratory motion leads to reduced contrast and quantitative accuracy and that image quantification depends on both the amplitude and the pattern of the respiratory motion. We verified that respiratory motion can have a major effect on the accuracy of measurement of lung lesions and that respiratory gating can reduce activity smearing on SPECT images

  6. Feasibility study of multi-pass respiratory-gated helical tomotherapy of a moving target via binary MLC closure

    Science.gov (United States)

    Kim, Bryan; Chen, Jeff; Kron, Tomas; Battista, Jerry

    2010-11-01

    Gated radiotherapy of lung lesions is particularly complex for helical tomotherapy, due to the simultaneous motions of its three subsystems (gantry, couch and collimator). We propose a new way to implement gating for helical tomotherapy, namely multi-pass respiratory gating. In this method, gating is achieved by delivering only the beam projections that occur within a respiratory gating window, while blocking the rest of the beam projections by fully closing all collimator leaves. Due to the continuous couch motion, the planned beam projections must be delivered over multiple passes of radiation deliveries. After each pass, the patient couch is reset to its starting position, and the treatment recommences at a different phase of tumour motion to 'fill in' the previously blocked beam projections. The gating process may be repeated until the plan dose is delivered (full gating), or halted after a certain number of passes, with the entire remaining dose delivered in a final pass without gating (partial gating). The feasibility of the full gating approach was first tested for sinusoidal target motion, through experimental measurements with film and computer simulation. The optimal gating parameters for full and partial gating methods were then determined for various fractionation schemes through computer simulation, using a patient respiratory waveform. For sinusoidal motion, the PTV dose deviations of -29 to 5% observed without gating were reduced to range from -1 to 3% for a single fraction, with a 4 pass full gating. For a patient waveform, partial gating required fewer passes than full gating for all fractionation schemes. For a single fraction, the maximum allowed residual motion was only 4 mm, requiring large numbers of passes for both full (12) and partial (7 + 1) gating methods. The number of required passes decreased significantly for 3 and 30 fractions, allowing residual motion up to 7 mm. Overall, the multi-pass gating technique was shown to be a promising

  7. Feasibility study of multi-pass respiratory-gated helical tomotherapy of a moving target via binary MLC closure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bryan; Chen, Jeff; Battista, Jerry [London Regional Cancer Program, London Health Sciences Centre, London, ON (Canada); Kron, Tomas, E-mail: bryan.kim@lhsc.on.c [Peter MacCallum Cancer Center, Melbourne (Australia)

    2010-11-21

    Gated radiotherapy of lung lesions is particularly complex for helical tomotherapy, due to the simultaneous motions of its three subsystems (gantry, couch and collimator). We propose a new way to implement gating for helical tomotherapy, namely multi-pass respiratory gating. In this method, gating is achieved by delivering only the beam projections that occur within a respiratory gating window, while blocking the rest of the beam projections by fully closing all collimator leaves. Due to the continuous couch motion, the planned beam projections must be delivered over multiple passes of radiation deliveries. After each pass, the patient couch is reset to its starting position, and the treatment recommences at a different phase of tumour motion to 'fill in' the previously blocked beam projections. The gating process may be repeated until the plan dose is delivered (full gating), or halted after a certain number of passes, with the entire remaining dose delivered in a final pass without gating (partial gating). The feasibility of the full gating approach was first tested for sinusoidal target motion, through experimental measurements with film and computer simulation. The optimal gating parameters for full and partial gating methods were then determined for various fractionation schemes through computer simulation, using a patient respiratory waveform. For sinusoidal motion, the PTV dose deviations of -29 to 5% observed without gating were reduced to range from -1 to 3% for a single fraction, with a 4 pass full gating. For a patient waveform, partial gating required fewer passes than full gating for all fractionation schemes. For a single fraction, the maximum allowed residual motion was only 4 mm, requiring large numbers of passes for both full (12) and partial (7 + 1) gating methods. The number of required passes decreased significantly for 3 and 30 fractions, allowing residual motion up to 7 mm. Overall, the multi-pass gating technique was shown to be a

  8. Systematic errors in respiratory gating due to intrafraction deformations of the liver

    International Nuclear Information System (INIS)

    Siebenthal, Martin von; Szekely, Gabor; Lomax, Antony J.; Cattin, Philippe C.

    2007-01-01

    This article shows the limitations of respiratory gating due to intrafraction deformations of the right liver lobe. The variability of organ shape and motion over tens of minutes was taken into account for this evaluation, which closes the gap between short-term analysis of a few regular cycles, as it is possible with 4DCT, and long-term analysis of interfraction motion. Time resolved MR volumes (4D MR sequences) were reconstructed for 12 volunteers and subsequent non-rigid registration provided estimates of the 3D trajectories of points within the liver over time. The full motion during free breathing and its distribution over the liver were quantified and respiratory gating was simulated to determine the gating accuracy for different gating signals, duty cycles, and different intervals between patient setup and treatment. Gating effectively compensated for the respiratory motion within short sequences (3 min), but deformations, mainly in the anterior inferior part (Couinaud segments IVb and V), led to systematic deviations from the setup position of more than 5 mm in 7 of 12 subjects after 20 min. We conclude that measurements over a few breathing cycles should not be used as a proof of accurate reproducibility of motion, not even within the same fraction, if it is longer than a few minutes. Although the diaphragm shows the largest magnitude of motion, it should not be used to assess the gating accuracy over the entire liver because the reproducibility is typically much more limited in inferior parts. Simple gating signals, such as the trajectory of skin motion, can detect the exhalation phase, but do not allow for an absolute localization of the complete liver over longer periods because the drift of these signals does not necessarily correlate with the internal drift

  9. Fully automated intrinsic respiratory and cardiac gating for small animal CT

    Energy Technology Data Exchange (ETDEWEB)

    Kuntz, J; Baeuerle, T; Semmler, W; Bartling, S H [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Dinkel, J [Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Zwick, S [Department of Diagnostic Radiology, Medical Physics, Freiburg University (Germany); Grasruck, M [Siemens Healthcare, Forchheim (Germany); Kiessling, F [Chair of Experimental Molecular Imaging, RWTH-Aachen University, Medical Faculty, Aachen (Germany); Gupta, R [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States)], E-mail: j.kuntz@dkfz.de

    2010-04-07

    A fully automated, intrinsic gating algorithm for small animal cone-beam CT is described and evaluated. A parameter representing the organ motion, derived from the raw projection images, is used for both cardiac and respiratory gating. The proposed algorithm makes it possible to reconstruct motion-corrected still images as well as to generate four-dimensional (4D) datasets representing the cardiac and pulmonary anatomy of free-breathing animals without the use of electrocardiogram (ECG) or respiratory sensors. Variation analysis of projections from several rotations is used to place a region of interest (ROI) on the diaphragm. The ROI is cranially extended to include the heart. The centre of mass (COM) variation within this ROI, the filtered frequency response and the local maxima are used to derive a binary motion-gating parameter for phase-sensitive gated reconstruction. This algorithm was implemented on a flat-panel-based cone-beam CT scanner and evaluated using a moving phantom and animal scans (seven rats and eight mice). Volumes were determined using a semiautomatic segmentation. In all cases robust gating signals could be obtained. The maximum volume error in phantom studies was less than 6%. By utilizing extrinsic gating via externally placed cardiac and respiratory sensors, the functional parameters (e.g. cardiac ejection fraction) and image quality were equivalent to this current gold standard. This algorithm obviates the necessity of both gating hardware and user interaction. The simplicity of the proposed algorithm enables adoption in a wide range of small animal cone-beam CT scanners.

  10. Improved method of in vivo respiratory-gated micro-CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Walters, Erin B; Panda, Kunal; Bankson, James A; Brown, Ellana; Cody, Dianna D [Department of Imaging Physics, Unit 56, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030 (United States)

    2004-09-07

    The presence of motion artifacts is a typical problem in thoracic imaging. However, synchronizing the respiratory cycle with computed tomography (CT) image acquisition can reduce these artifacts. We currently employ a method of in vivo respiratory-gated micro-CT imaging for small laboratory animals (mice). This procedure involves the use of a ventilator that controls the respiratory cycle of the animal and provides a digital output signal that is used to trigger data acquisition. After inspection of the default respiratory trigger timing, we hypothesized that image quality could be improved by moving the data-acquisition window to a portion of the cycle with less respiratory motion. For this reason, we developed a simple delay circuit to adjust the timing of the ventilator signal that initiates micro-CT data acquisition. This delay circuit decreases motion artifacts and substantially improves image quality.

  11. Improved method of in vivo respiratory-gated micro-CT imaging

    International Nuclear Information System (INIS)

    Walters, Erin B; Panda, Kunal; Bankson, James A; Brown, Ellana; Cody, Dianna D

    2004-01-01

    The presence of motion artifacts is a typical problem in thoracic imaging. However, synchronizing the respiratory cycle with computed tomography (CT) image acquisition can reduce these artifacts. We currently employ a method of in vivo respiratory-gated micro-CT imaging for small laboratory animals (mice). This procedure involves the use of a ventilator that controls the respiratory cycle of the animal and provides a digital output signal that is used to trigger data acquisition. After inspection of the default respiratory trigger timing, we hypothesized that image quality could be improved by moving the data-acquisition window to a portion of the cycle with less respiratory motion. For this reason, we developed a simple delay circuit to adjust the timing of the ventilator signal that initiates micro-CT data acquisition. This delay circuit decreases motion artifacts and substantially improves image quality

  12. Evaluation of the MEMS based portable respiratory training system with a tactile sensor for respiratory-gated radiotherapy

    Science.gov (United States)

    Moon, Sun Young; Yoon, Myonggeun; Chung, Mijoo; Chung, Weon Kuu; Kim, Dong Wook

    2017-10-01

    In respiratory-gated radiotherapy, it is important to maintain the regular respiratory cycles of patients. If patients undergo respiration training, their regular breathing pattern is affected. Therefore, we developed a respiratory training system based on a micro electromechanical system (MEMS) and evaluated the feasibility of the MEMS in radiotherapy. By comparing the measured signal before and after radiation exposure, we confirmed the effects of radiation. By evaluating the period of the electric signal emitted by a tactile sensor and its constancy, the performance of the tactile sensor was confirmed. Moreover, by comparing the delay between the motion of the MEMS and the electric signal from the tactile sensor, we confirmed the reaction time of the tactile sensor. The results showed that a baseline shift occurred for an accumulated dose of 400 Gy in the sensor, and both the amplitude and period changed. The period of the signal released by the tactile sensor was 5.39 and its standard deviation was 0.06. Considering the errors from the motion phantom, a standard deviation of 0.06 was desirable. The delay time was within 0.5 s and not distinguishable by a patient. We confirmed the performance of the MEMS and concluded that MEMS could be applied to patients for respiratory-gated radiotherapy.

  13. Issues in quantification of registered respiratory gated PET/CT in the lung

    Science.gov (United States)

    Cuplov, Vesna; Holman, Beverley F.; McClelland, Jamie; Modat, Marc; Hutton, Brian F.; Thielemans, Kris

    2018-01-01

    PET/CT quantification of lung tissue is limited by several difficulties: the lung density and local volume changes during respiration, the anatomical mismatch between PET and CT and the relative contributions of tissue, air and blood to the PET signal (the tissue fraction effect). Air fraction correction (AFC) has been shown to improve PET image quantification in the lungs. Methods to correct for the movement and anatomical mismatch involve respiratory gating and image registration techniques. While conventional registration methods only account for spatial mismatch, the Jacobian determinant of the deformable registration transformation field can be used to estimate local volume changes and could therefore potentially be used to correct (i.e. Jacobian Correction, JC) the PET signal for changes in concentration due to local volume changes. This work aims to investigate the relationship between variations in the lung due to respiration, specifically density, tracer concentration and local volume changes. In particular, we study the effect of AFC and JC on PET quantitation after registration of respiratory gated PET/CT patient data. Six patients suffering from lung cancer with solitary pulmonary nodules underwent 18 F-FDG PET/cine-CT. The PET data were gated into six respiratory gates using displacement gating based on a real-time position management (RPM) signal and reconstructed with matched gated CT. The PET tracer concentration and tissue density were extracted from registered gated PET and CT images before and after corrections (AFC or JC) and compared to the values from the reference images. Before correction, we observed a linear correlation between the PET tracer concentration values and density. Across all gates and patients, the maximum relative change in PET tracer concentration before (after) AFC was found to be 16.2% (4.1%) and the maximum relative change in tissue density and PET tracer concentration before (after) JC was found to be 17.1% (5.5%) and 16

  14. Amplitude-based optimal respiratory gating in positron emission tomography in patients with primary lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Grootjans, Willem; Meeuwis, Antoi P.W.; Vos, Charlotte S. van der; Gotthardt, Martin; Oyen, Wim J.G.; Visser, Eric P. [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, P.O. Box 9101, Nijmegen (Netherlands); Geus-Oei, Lioe-Fee de [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, P.O. Box 9101, Nijmegen (Netherlands); University of Twente, MIRA Institute for Biomedical Technology and Technical Medicine, Enschede (Netherlands)

    2014-12-15

    Respiratory motion during PET imaging introduces quantitative and diagnostic inaccuracies, which may result in non-optimal patient management. This study investigated the effects of respiratory gating on image quantification using an amplitude-based optimal respiratory gating (ORG) algorithm. Whole body FDG-PET/CT was performed in 66 lung cancer patients. The respiratory signal was obtained using a pressure sensor integrated in an elastic belt placed around the patient's thorax. ORG images were reconstructed with 50 %, 35 %, and 20 % of acquired PET data (duty cycle). Lesions were grouped into anatomical locations. Differences in lesion volume between ORG and non-gated images, and mean FDG-uptake (SUV{sub mean}) were calculated. Lesions in the middle and lower lobes demonstrated a significant SUV{sub mean} increase for all duty cycles and volume decrease for duty cycles of 35 % and 20 %. Significant increase in SUV{sub mean} and decrease in volume for lesions in the upper lobes were observed for a 20 % duty cycle. The SUV{sub mean} increase for central lesions was significant for all duty cycles, whereas a significant volume decrease was observed for a duty cycle of 20 %. This study implies that ORG could influence clinical PET imaging with respect to response monitoring and radiotherapy planning. (orig.)

  15. Data-driven gating in PET: Influence of respiratory signal noise on motion resolution.

    Science.gov (United States)

    Büther, Florian; Ernst, Iris; Frohwein, Lynn Johann; Pouw, Joost; Schäfers, Klaus Peter; Stegger, Lars

    2018-05-21

    Data-driven gating (DDG) approaches for positron emission tomography (PET) are interesting alternatives to conventional hardware-based gating methods. In DDG, the measured PET data themselves are utilized to calculate a respiratory signal, that is, subsequently used for gating purposes. The success of gating is then highly dependent on the statistical quality of the PET data. In this study, we investigate how this quality determines signal noise and thus motion resolution in clinical PET scans using a center-of-mass-based (COM) DDG approach, specifically with regard to motion management of target structures in future radiotherapy planning applications. PET list mode datasets acquired in one bed position of 19 different radiotherapy patients undergoing pretreatment [ 18 F]FDG PET/CT or [ 18 F]FDG PET/MRI were included into this retrospective study. All scans were performed over a region with organs (myocardium, kidneys) or tumor lesions of high tracer uptake and under free breathing. Aside from the original list mode data, datasets with progressively decreasing PET statistics were generated. From these, COM DDG signals were derived for subsequent amplitude-based gating of the original list mode file. The apparent respiratory shift d from end-expiration to end-inspiration was determined from the gated images and expressed as a function of signal-to-noise ratio SNR of the determined gating signals. This relation was tested against additional 25 [ 18 F]FDG PET/MRI list mode datasets where high-precision MR navigator-like respiratory signals were available as reference signal for respiratory gating of PET data, and data from a dedicated thorax phantom scan. All original 19 high-quality list mode datasets demonstrated the same behavior in terms of motion resolution when reducing the amount of list mode events for DDG signal generation. Ratios and directions of respiratory shifts between end-respiratory gates and the respective nongated image were constant over all

  16. Evaluation of irradiation position in respiratory-gated radiotherapy using a phantom system simulating patient respiration

    International Nuclear Information System (INIS)

    Oyama, Masaya; Ueda, Takashi; Kitoh, Satoshi; Tanaka, Takashi; Goka, Tomonori; Ogino, Takashi

    2006-01-01

    Respiratory-gated (RG) radiotherapy is useful for minimizing the irradiated volume of normal tissues resulting from the shifting of internal structures caused by respiratory movement. The present study was conducted to evaluate the treatment field in RG radiotherapy using a phantom system simulating patient respiration. A phantom system consisting of a 3-cm ball-shaped dummy tumor and film placed in a cork lung phantom was used (THK Co., Ltd.). RG radiotherapy was employed in the expiratory phase. The phantom movement distance was set to 2 cm, and the gating signals from a respiratory-gating system (AZ-733V, Anzai Medical) were varied. The settings used for irradiation were an X-ray energy of 6 MV (PRIMUS, Toshiba Medical Systems), treatment field of 5 cm x 7 cm, and X-ray dose of 100 MU. Images were acquired using an electric portal-imaging device (EPID, OPTIVUE 500), and the X-ray dose distribution was measured by the film method. In images acquired using the EPID, the tumor margins became less clear when the gating signals were increased, and the ITVs were determined to be 3.6 cm, 3.7 cm, 4.2 cm, and 5.1 cm at gating rates of 10%, 25%, 50%, and no gate, respectively. With regard to the X-ray dose distribution measured by the film method, the dose profile in the cephalocaudal direction was shifted toward the expiratory phase, and the degree of shift became greater when the gating signals were increased. In addition, the optimal treatment fields in the cephalocaudal direction were determined to be 5.2 cm, 5.2 cm, 5.6 cm, and 7.0 cm at gating rates of 10%, 25%, 50%, and no gating, respectively. Although RG radiotherapy is useful for improving the accuracy of radiotherapy, the characteristics of the RG radiotherapy technique and the radiotherapy system must be clearly understood when this method is to be employed in clinical practice. Image-guided radiotherapy (IGRT) is now assuming a central role in radiotherapy, and properly identifying internal margins is an

  17. Evaluation of respiratory movement during gated radiotherapy using film and electronic portal imaging

    International Nuclear Information System (INIS)

    Ford, E.C.; Mageras, G.S.; Yorke, E.; Rosenzweig, K.E.; Wagman, R.; Ling, C.C.

    2002-01-01

    Purpose: To evaluate the effectiveness of a commercial system in reducing respiration-induced treatment uncertainty by gating the radiation delivery. Methods and Materials: The gating system considered here measures respiration from the position of a reflective marker on the patient's chest. Respiration-triggered planning CT scans were obtained for 8 patients (4 lung, 4 liver) at the intended phase of respiration (6 at end expiration and 2 at end inspiration). In addition, fluoroscopic movies were recorded simultaneously with the respiratory waveform. During the treatment sessions, gated localization films were used to measure the position of the diaphragm relative to the vertebral bodies, which was compared to the reference digitally reconstructed radiograph derived from the respiration-triggered planning CT. Variability was quantified by the standard deviation about the mean position. We also assessed the interfraction variability of soft tissue structures during gated treatment in 2 patients using an amorphous silicon electronic portal imaging device. Results: The gated localization films revealed an interfraction patient-averaged diaphragm variability of 2.8±1.0 mm (error bars indicate standard deviation in the patient population). The fluoroscopic data yielded a patient-averaged intrafraction diaphragm variability of 2.6±1.7 mm. With no gating, this intrafraction excursion became 6.9±2.1 mm. In gated localization films, the patient-averaged mean displacement of the diaphragm from the planning position was 0.0±3.9 mm. However, in 4 of the 8 patients, the mean (over localization films) displacement was >4 mm, indicating a systematic displacement in treatment position from the planned one. The position of soft tissue features observed in portal images during gated treatments over several fractions showed a mean variability between 2.6 and 5.7 mm. The intrafraction variability, however, was between 0.6 and 1.4 mm, indicating that most of the variability was

  18. End-expiration respiratory gating for a high-resolution stationary cardiac SPECT system

    International Nuclear Information System (INIS)

    Chan, Chung; Sinusas, Albert J; Liu, Chi; Harris, Mark; Le, Max; Biondi, James; Grobshtein, Yariv; Liu, Yi-Hwa

    2014-01-01

    Respiratory and cardiac motions can degrade myocardial perfusion SPECT (MPS) image quality and reduce defect detection and quantitative accuracy. In this study, we developed a dual respiratory and cardiac gating system for a high-resolution fully stationary cardiac SPECT scanner in order to improve the image quality and defect detection. Respiratory motion was monitored using a compressive sensor pillow connected to a dual respiratory–cardiac gating box, which sends cardiac triggers only during end-expiration phases to the single cardiac trigger input on the SPECT scanners. The listmode data were rebinned retrospectively into end-expiration frames for respiratory motion reduction or eight cardiac gates only during end-expiration phases to compensate for both respiratory and cardiac motions. The proposed method was first validated on a motion phantom in the presence and absence of multiple perfusion defects, and then applied on 11 patient studies with and without perfusion defects. In the normal phantom studies, the end-expiration gated SPECT (EXG-SPECT) reduced respiratory motion blur and increased myocardium to blood pool contrast by 51.2% as compared to the ungated images. The proposed method also yielded an average of 11.2% increase in myocardium to defect contrast as compared to the ungated images in the phantom studies with perfusion defects. In the patient studies, EXG-SPECT significantly improved the myocardium to blood pool contrast (p < 0.005) by 24% on average as compared to the ungated images, and led to improved perfusion uniformity across segments on polar maps for normal patients. For a patient with defect, EXG-SPECT improved the defect contrast and definition. The dual respiratory–cardiac gating further reduced the blurring effect, increased the myocardium to blood pool contrast significantly by 36% (p < 0.05) compared to EXG-SPECT, and further improved defect characteristics and visualization of fine structures at the expense of increased

  19. Audiovisual biofeedback improves image quality and reduces scan time for respiratory-gated 3D MRI

    International Nuclear Information System (INIS)

    Lee, D; Keall, P; Kim, T; Greer, P B; Arm, J

    2014-01-01

    The purpose of this study was to test the hypothesis that audiovisual (AV) biofeedback can improve image quality and reduce scan time for respiratory-gated 3D thoracic MRI. For five healthy human subjects respiratory motion guidance in MR scans was provided using an AV biofeedback system, utilizing real-time respiratory motion signals. To investigate the improvement of respiratory-gated 3D MR images between free breathing (FB) and AV biofeedback (AV), each subject underwent two imaging sessions. Respiratory-related motion artifacts and imaging time were qualitatively evaluated in addition to the reproducibility of external (abdominal) motion. In the results, 3D MR images in AV biofeedback showed more anatomic information such as a clear distinction of diaphragm, lung lobes and sharper organ boundaries. The scan time was reduced from 401±215 s in FB to 334±94 s in AV (p-value 0.36). The root mean square variation of the displacement and period of the abdominal motion was reduced from 0.4±0.22 cm and 2.8±2.5 s in FB to 0.1±0.15 cm and 0.9±1.3 s in AV (p-value of displacement <0.01 and p-value of period 0.12). This study demonstrated that audiovisual biofeedback improves image quality and reduces scan time for respiratory-gated 3D MRI. These results suggest that AV biofeedback has the potential to be a useful motion management tool in medical imaging and radiation therapy procedures.

  20. Automatic intrinsic cardiac and respiratory gating from cone-beam CT scans of the thorax region

    Science.gov (United States)

    Hahn, Andreas; Sauppe, Sebastian; Lell, Michael; Kachelrieß, Marc

    2016-03-01

    We present a new algorithm that allows for raw data-based automated cardiac and respiratory intrinsic gating in cone-beam CT scans. It can be summarized in three steps: First, a median filter is applied to an initially reconstructed volume. The forward projection of this volume contains less motion information and is subtracted from the original projections. This results in new raw data that contain only moving and not static anatomy like bones, that would otherwise impede the cardiac or respiratory signal acquisition. All further steps are applied to these modified raw data. Second, the raw data are cropped to a region of interest (ROI). The ROI in the raw data is determined by the forward projection of a binary volume of interest (VOI) that includes the diaphragm for respiratory gating and most of the edge of the heart for cardiac gating. Third, the mean gray value in this ROI is calculated for every projection and the respiratory/cardiac signal is acquired using a bandpass filter. Steps two and three are carried out simultaneously for 64 or 1440 overlapping VOI inside the body for the respiratory or cardiac signal respectively. The signals acquired from each ROI are compared and the most consistent one is chosen as the desired cardiac or respiratory motion signal. Consistency is assessed by the standard deviation of the time between two maxima. The robustness and efficiency of the method is evaluated using simulated and measured patient data by computing the standard deviation of the mean signal difference between the ground truth and the intrinsic signal.

  1. SPECT acquisition using dynamic projections: a novel approach for data-driven respiratory gating

    International Nuclear Information System (INIS)

    Hutton, B.F.; Hatton, R.L.; Yip, N.

    2002-01-01

    Full text: Movement of the heart due to respiration has been previously demonstrated to produce potentially serious artefacts. On-line respiratory gating is difficult, as it requires a high level of patient cooperation. We demonstrate that use of dynamic acquisition of projections permits identification of the respiratory dynamics, allowing retrospective selection of data corresponding to a fixed point in the respiratory cycle. To demonstrate the feasibility of the technique a dynamic study was acquired just prior to myocardial per-fusion SPECT acquisition, using 5 frames/sec for 20 seconds (64*64 matrix) in anterior and lateral projections (using a dual-head right-angled configuration). The dynamic was processed a) by compressing frames in the transverse direction so as to illustrate time dependence, b) by plotting the centre of mass in the axial direction as a function of time. Respiratory motion was enhanced by use of temporal smoothing and intensity thresholding. In ten patients studied the cyclic pattern of motion due to respiratory dynamics was clearly visible in nine. Respiration typically resulted in around 1cm axial translation but in some individuals, movements as large as 3 cm were identified. The respiration rate ranged from 12-18 /min in agreement with independent observation of the patient's breathing pattern. These results suggest that retrospective respiratory gating is feasible without the need for any external respiratory monitoring device, provide that dynamic acquisition of SPECT projections is implemented. Correction for respiratory motion may also be feasible using this technique. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  2. Quantifying lung morphology with respiratory-gated micro-CT in a murine model of emphysema

    Science.gov (United States)

    Ford, N. L.; Martin, E. L.; Lewis, J. F.; Veldhuizen, R. A. W.; Holdsworth, D. W.; Drangova, M.

    2009-04-01

    Non-invasive micro-CT imaging techniques have been developed to investigate lung structure in free-breathing rodents. In this study, we investigate the utility of retrospectively respiratory-gated micro-CT imaging in an emphysema model to determine if anatomical changes could be observed in the image-derived quantitative analysis at two respiratory phases. The emphysema model chosen was a well-characterized, genetically altered model (TIMP-3 knockout mice) that exhibits a homogeneous phenotype. Micro-CT scans of the free-breathing, anaesthetized mice were obtained in 50 s and retrospectively respiratory sorted and reconstructed, providing 3D images representing peak inspiration and end expiration with 0.15 mm isotropic voxel spacing. Anatomical measurements included the volume and CT density of the lungs and the volume of the major airways, along with the diameters of the trachea, left bronchus and right bronchus. From these measurements, functional parameters such as functional residual capacity and tidal volume were calculated. Significant differences between the wild-type and TIMP-3 knockout groups were observed for measurements of CT density over the entire lung, indicating increased air content in the lungs of TIMP-3 knockout mice. These results demonstrate retrospective respiratory-gated micro-CT, providing images at multiple respiratory phases that can be analyzed quantitatively to investigate anatomical changes in murine models of emphysema.

  3. Quantifying lung morphology with respiratory-gated micro-CT in a murine model of emphysema

    International Nuclear Information System (INIS)

    Ford, N L; Martin, E L; Lewis, J F; Veldhuizen, R A W; Holdsworth, D W; Drangova, M

    2009-01-01

    Non-invasive micro-CT imaging techniques have been developed to investigate lung structure in free-breathing rodents. In this study, we investigate the utility of retrospectively respiratory-gated micro-CT imaging in an emphysema model to determine if anatomical changes could be observed in the image-derived quantitative analysis at two respiratory phases. The emphysema model chosen was a well-characterized, genetically altered model (TIMP-3 knockout mice) that exhibits a homogeneous phenotype. Micro-CT scans of the free-breathing, anaesthetized mice were obtained in 50 s and retrospectively respiratory sorted and reconstructed, providing 3D images representing peak inspiration and end expiration with 0.15 mm isotropic voxel spacing. Anatomical measurements included the volume and CT density of the lungs and the volume of the major airways, along with the diameters of the trachea, left bronchus and right bronchus. From these measurements, functional parameters such as functional residual capacity and tidal volume were calculated. Significant differences between the wild-type and TIMP-3 knockout groups were observed for measurements of CT density over the entire lung, indicating increased air content in the lungs of TIMP-3 knockout mice. These results demonstrate retrospective respiratory-gated micro-CT, providing images at multiple respiratory phases that can be analyzed quantitatively to investigate anatomical changes in murine models of emphysema.

  4. Quantifying lung morphology with respiratory-gated micro-CT in a murine model of emphysema

    Energy Technology Data Exchange (ETDEWEB)

    Ford, N L [Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada); Martin, E L; Lewis, J F; Veldhuizen, R A W [Lawson Health Research Institute, 268 Grosvenor Street, London, Ontario N6A 4V2 (Canada); Holdsworth, D W; Drangova, M [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, PO Box 5015, London, Ontario N6A 5K8 (Canada)], E-mail: nlford@ryerson.ca

    2009-04-07

    Non-invasive micro-CT imaging techniques have been developed to investigate lung structure in free-breathing rodents. In this study, we investigate the utility of retrospectively respiratory-gated micro-CT imaging in an emphysema model to determine if anatomical changes could be observed in the image-derived quantitative analysis at two respiratory phases. The emphysema model chosen was a well-characterized, genetically altered model (TIMP-3 knockout mice) that exhibits a homogeneous phenotype. Micro-CT scans of the free-breathing, anaesthetized mice were obtained in 50 s and retrospectively respiratory sorted and reconstructed, providing 3D images representing peak inspiration and end expiration with 0.15 mm isotropic voxel spacing. Anatomical measurements included the volume and CT density of the lungs and the volume of the major airways, along with the diameters of the trachea, left bronchus and right bronchus. From these measurements, functional parameters such as functional residual capacity and tidal volume were calculated. Significant differences between the wild-type and TIMP-3 knockout groups were observed for measurements of CT density over the entire lung, indicating increased air content in the lungs of TIMP-3 knockout mice. These results demonstrate retrospective respiratory-gated micro-CT, providing images at multiple respiratory phases that can be analyzed quantitatively to investigate anatomical changes in murine models of emphysema.

  5. Detection of respiratory tumour motion using intrinsic list mode-driven gating in positron emission tomography.

    Science.gov (United States)

    Büther, Florian; Ernst, Iris; Dawood, Mohammad; Kraxner, Peter; Schäfers, Michael; Schober, Otmar; Schäfers, Klaus P

    2010-12-01

    Respiratory motion of organs during PET scans is known to degrade PET image quality, potentially resulting in blurred images, attenuation artefacts and erroneous tracer quantification. List mode-based gating has been shown to reduce these pitfalls in cardiac PET. This study evaluates these intrinsic gating methods for tumour PET scans. A total of 34 patients with liver or lung tumours (14 liver tumours and 27 lung tumours in all) underwent a 15-min single-bed list mode PET scan of the tumour region. Of these, 15 patients (8 liver and 11 lung tumours in total) were monitored by a video camera registering a marker on the patient's abdomen, thus capturing the respiratory motion for PET gating (video method). Further gating information was deduced by dividing the list mode stream into 200-ms frames, determining the number of coincidences (sensitivity method) and computing the axial centre of mass of the measured count rates in the same frames (centre of mass method). Additionally, these list mode-based methods were evaluated using only coincidences originating from the tumour region by segmenting the tumour in sinogram space (segmented sensitivity/centre of mass method). Measured displacement of the tumours between end-expiration and end-inspiration and the increase in apparent uptake in the gated images served as a measure for the exactness of gating. To estimate the accuracy, a thorax phantom study with moved activity sources simulating small tumours was also performed. All methods resolved the respiratory motion with varying success. The best results were seen in the segmented centre of mass method, on average leading to larger displacements and uptake values than the other methods. The simple centre of mass method performed worse in terms of displacements due to activities moving into the field of view during the respiratory cycle. Both sensitivity- and video-based methods lead to similar results. List mode-driven PET gating, especially the segmented centre of mass

  6. Establishing tumour tracking accuracy in free-breathing respiratory gated SBRT of lung cancer

    International Nuclear Information System (INIS)

    Wen, Chuan-Dong; Wong, C; Ackerly, T; Ruben, J; Millar, J

    2014-01-01

    Free-breathing respiratory gated SBRT of surgically inoperable lung cancer has been clinically commissioned. This study was to establish the tumour tracking accuracy under clinical conditions based on an implanted fiducial marker. A Visicoil TM marker embedded in tissue-equivalent material mounted in a phantom (ET Gating Phantom TM Brainlab) driven by a patient's breathing data was treated with the ExacTrac TM system. This one-dimensional moving marker represented a tumour motion in superior-inferior (S-I) direction measured through 4DCT study of the same patient. Both Gafchromic TM films and the stereoscopic kV images were used for tracking the position of the marker. For tumour motion at magnitudes of 10, 20 and 29 mm and treated with corresponding gate widths of 50%, 33% and 20% of free breathing amplitude, the implanted marker was able to be tracked with a deviation ≤1.53 mm to its planned position.

  7. Residual Motion and Duty Time in Respiratory Gating Radiotherapy Using Individualized or Population-Based Windows

    International Nuclear Information System (INIS)

    Fuji, Hiroshi; Asada, Yoshihiro; Numano, Masumi; Yamashita, Haruo; Nishimura, Tetsuo; Hashimoto, Takayuki; Harada, Hideyuki; Asakura, Hirofumi; Murayama, Shigeyuki

    2009-01-01

    Purpose: The efficiency and precision of respiratory gated radiation therapy for tumors is affected by variations in respiration-induced tumor motion. We evaluated the use of individualized and population-based parameters for such treatment. Methods and Materials: External respiratory signal records and images of respiration-induced tumor motion were obtained from 42 patients undergoing respiratory gated radiation therapy for liver tumors. Gating window widths were calculated for each patient, with 2, 4, and 10 mm of residual motion, and the mean was defined as the population-based window width. Residual motions based on population-based and predefined window widths were compared. Duty times based on whole treatment sessions, at various window levels, were calculated. The window level giving the longest duty time was defined as the individualized most efficient level (MEL). MELs were also calculated based on the first 10 breathing cycles. The duty times for population-based MELs (defined as mean MELs) and individualized MELs were compared. Results: Tracks of respiration-induced tumor motion ranged from 3 to 50 mm. Half of the patients had larger actual residual motions than the assigned residual motions. Duty times were greater when based on individualized, rather than population-based, window widths. The MELs established during whole treatment sessions for 2 mm and 4 mm of residual motion gave significantly increased duty times, whereas those calculated using the first 10 breathing cycles showed only marginal increases. Conclusions: Using individualized window widths and levels provided more precise and efficient respiratory gated radiation therapy. However, methods for predicting individualized window levels before treatment remain to be explored.

  8. Evaluation of respiratory and cardiac motion correction schemes in dual gated PET/CT cardiac imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lamare, F., E-mail: frederic.lamare@chu-bordeaux.fr; Fernandez, P. [Univ. Bordeaux, INCIA, UMR 5287, F-33400 Talence (France); CNRS, INCIA, UMR 5287, F-33400 Talence (France); Service de Médecine Nucléaire, Hôpital Pellegrin, CHU de Bordeaux, 33076 Bordeaux (France); Le Maitre, A.; Visvikis, D. [INSERM, UMR1101, LaTIM, Université de Bretagne Occidentale, 29609 Brest (France); Dawood, M.; Schäfers, K. P. [European Institute for Molecular Imaging, University of Münster, Mendelstr. 11, 48149 Münster (Germany); Rimoldi, O. E. [Vita-Salute University and Scientific Institute San Raffaele, Milan, Italy and CNR Istituto di Bioimmagini e Fisiologia Molecolare, Milan (Italy)

    2014-07-15

    Purpose: Cardiac imaging suffers from both respiratory and cardiac motion. One of the proposed solutions involves double gated acquisitions. Although such an approach may lead to both respiratory and cardiac motion compensation there are issues associated with (a) the combination of data from cardiac and respiratory motion bins, and (b) poor statistical quality images as a result of using only part of the acquired data. The main objective of this work was to evaluate different schemes of combining binned data in order to identify the best strategy to reconstruct motion free cardiac images from dual gated positron emission tomography (PET) acquisitions. Methods: A digital phantom study as well as seven human studies were used in this evaluation. PET data were acquired in list mode (LM). A real-time position management system and an electrocardiogram device were used to provide the respiratory and cardiac motion triggers registered within the LM file. Acquired data were subsequently binned considering four and six cardiac gates, or the diastole only in combination with eight respiratory amplitude gates. PET images were corrected for attenuation, but no randoms nor scatter corrections were included. Reconstructed images from each of the bins considered above were subsequently used in combination with an affine or an elastic registration algorithm to derive transformation parameters allowing the combination of all acquired data in a particular position in the cardiac and respiratory cycles. Images were assessed in terms of signal-to-noise ratio (SNR), contrast, image profile, coefficient-of-variation (COV), and relative difference of the recovered activity concentration. Results: Regardless of the considered motion compensation strategy, the nonrigid motion model performed better than the affine model, leading to higher SNR and contrast combined with a lower COV. Nevertheless, when compensating for respiration only, no statistically significant differences were

  9. Magnetic resonance imaging of the coronary arteries : clinical results from three dimensional evaluation of a respiratory gated technique

    NARCIS (Netherlands)

    van Geuns, R J; de Bruin, H G; Rensing, B J; Wielopolski, P A; Hulshoff, M D; van Ooijen, P M; Oudkerk, M; de Feyter, P J

    1999-01-01

    BACKGROUND: Magnetic resonance coronary angiography is challenging because of the motion of the vessels during cardiac contraction and respiration. Additional challenges are the small calibre of the arteries and their complex three dimensional course. Respiratory gating, turboflash acquisition, and

  10. Quantifying the impact of respiratory-gated 4D CT acquisition on thoracic image quality : a digital phantom study

    NARCIS (Netherlands)

    Bernatowicz, K; Keall, P; Mishra, P; Knopf, A; Lomax, A; Kipritidis, J

    PURPOSE: Prospective respiratory-gated 4D CT has been shown to reduce tumor image artifacts by up to 50% compared to conventional 4D CT. However, to date no studies have quantified the impact of gated 4D CT on normal lung tissue imaging, which is important in performing dose calculations based on

  11. Reproducibility of image quality for moving objects using respiratory-gated computed tomography. A study using a phantom model

    International Nuclear Information System (INIS)

    Fukumitsu, Nobuyoshi; Ishida, Masaya; Terunuma, Toshiyuki

    2012-01-01

    To investigate the reproducibility of computed tomography (CT) imaging quality in respiratory-gated radiation treatment planning is essential in radiotherapy of movable tumors. Seven series of regular and six series of irregular respiratory motions were performed using a thorax dynamic phantom. For the regular respiratory motions, the respiratory cycle was changed from 2.5 to 4 s and the amplitude was changed from 4 to 10 mm. For the irregular respiratory motions, a cycle of 2.5 to 4 or an amplitude of 4 to 10 mm was added to the base data (id est (i.e.) 3.5-s cycle, 6-mm amplitude) every three cycles. Images of the object were acquired six times using respiratory-gated data acquisition. The volume of the object was calculated and the reproducibility of the volume was decided based on the variety. The registered image of the object was added and the reproducibility of the shape was decided based on the degree of overlap of objects. The variety in the volumes and shapes differed significantly as the respiratory cycle changed according to regular respiratory motions. In irregular respiratory motion, shape reproducibility was further inferior, and the percentage of overlap among the six images was 35.26% in the 2.5- and 3.5-s cycle mixed group. Amplitude changes did not produce significant differences in the variety of the volumes and shapes. Respiratory cycle changes reduced the reproducibility of the image quality in respiratory-gated CT. (author)

  12. Implementation of respiratory-gated VMAT on a Versa HD linear accelerator.

    Science.gov (United States)

    Snyder, Jeffrey E; Flynn, Ryan T; Hyer, Daniel E

    2017-09-01

    The accurate delivery of respiratory-gated volumetric modulated arc therapy (VMAT) treatment plans presents a challenge since the gantry rotation and collimator leaves must be repeatedly stopped and set into motion during each breathing cycle. In this study, we present the commissioning process for an Anzai gating system (AZ-733VI) on an Elekta Versa HD linear accelerator and make recommendations for successful clinical implementation. The commissioning tests include central axis dose consistency, profile consistency, gating beam-on/off delay, and comparison of gated versus nongated gamma pass rates for patient-specific quality assurance using four clinically commissioned photon energies: 6 MV, 6 FFF, 10 MV, and 10 FFF. The central axis dose constancy between gated and nongated deliveries was within 0.6% for all energies and the analysis of open field profiles for gated and nongated deliveries showed an agreement of 97.8% or greater when evaluated with a percent difference criteria of 1%. The measurement of the beam-on/off delay was done by evaluating images of a moving ball-bearing phantom triggered by the gating system and average beam-on delays of 0.22-0.29 s were observed. No measurable beam-off delay was present. Measurements of gated VMAT dose distributions resulted in decrements as high as 9% in the gamma passing rate as compared to nongated deliveries when evaluated against the planned dose distribution at 3%/3 mm. By decreasing the dose rate, which decreases the gantry speed during gated delivery, the gamma passing rates of gated and nongated treatments can be made equivalent. We present an empirically derived formula to limit the maximum dose rate during VMAT deliveries and show that by implementing a reduced dose rate, a gamma passing rate of greater than 95% (3%/3 mm) was obtained for all plan measurements. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of

  13. Poster — Thur Eve — 37: Respiratory gating with an Elekta flattening filter free photon beam

    International Nuclear Information System (INIS)

    Péloquin, S; Furstoss, C; Munger, P; Wierzbicki, W; Carrier, J-F

    2014-01-01

    In cases where surgery is not possible for lung cancer treatment, stereotactic body radiation therapy (SBRT) may be an option. One problem when treating this type of cancer is the motion of the lungs caused by the patient's respiration. It is possible to reduce the impact of this movement with the use of respiratory gating. By combining respiratory gating with a flattening filter free (FFF) photon beam linac, the increased treatment time caused by a reduced beam-on time of respiratory gating methods can be compensated by the inherent increased dose rate of FFF beams. This project's aim is to create hardware and software interfaces allowing free respiration gating on an Elekta Synergy-S linac specially modified to deliver 6 MV FFF photon beams. First, a printed circuit board was created for reading the signal from a Bellows Belt from Philips (a respiration monitor belt) and transmitting an On/Off signal to the accelerator. A software was also developed to visualize patient respiration. Secondly, a FFF model was created with the Pinnacle treatment planning system from Philips. Gamma (Γ) analysis (2%, 2 mm) was used to evaluate model. For fields going from 5.6 × 5.6 to 12 × 12 cm 2 , central axis depth dose model fitting shows an average gamma value of 0.2 and 100% of gamma values remain under the Γ = 1 limit. For smaller fields (0.8 × 0.8 and 1.6 × 1.6 cm 2 ), Pinnacle has more trouble trying to fit the measurements, overestimating dose in penumbra and buildup regions

  14. Effectiveness of the Respiratory Gating System for Stereotectic Radiosurgery of Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Song, Heung Kwon; Kwon, Kyung Tae; Park, Cheol Su; Yang, Oh Nam; Kim, Min Su; Kim, Jeong Man [Dept. of Radiation Oncology, Asan Medical Center, Seoul (Korea, Republic of)

    2005-09-15

    For stereotactic radiosurgery (SRS) of a tumor in the region whose movement due to respiration is significant, like Lung lower lobe, the gated therapy, which delivers radiation dose to the selected respiratory phases when tumor motion is small, was performed using the Respiratory gating system and its clinical effectiveness was evaluated. For two SRS patients with a tumor in Lung lower lobe, a marker block (infrared reflector) was attached on the abdomen. While patient' respiratory cycle was monitored with Real-time Position Management (RPM, Varian, USA), 4D CT was performed (10 phases per a cycle). Phases in which tumor motion did not change rapidly were decided as treatment phases. The treatment volume was contoured on the CT images for selected treatment phases using maximum intensity projection (MIP) method. In order to verify setup reproducibility and positional variation, 4D CT was repeated. Gross tumor volume (GTV) showed maximum movement in superior-inferior direction. For patient no 1, motion of GTV was reduced to 2.6 mm in treatment phases (30-60%), while that was 9.4 mm in full phases (0-90%) and for patient no 2, it was reduced to 2.3 mm in treatment phases (30-70%), while it was 11.7 mm in full phases (0-90%). When comparing two sets of CT images, setup errors in all the directions were within 3 mm. Since tumor motion was reduced less than 5 mm, the Respiratory gating system for SRS of Lung lower lobe is useful.

  15. Contrast-enhanced specific absorption rate-efficient 3D cardiac cine with respiratory-triggered radiofrequency gating.

    Science.gov (United States)

    Henningsson, Markus; Chan, Raymond H; Goddu, Beth; Goepfert, Lois A; Razavi, Reza; Botnar, Rene M; Schaeffter, Tobias; Nezafat, Reza

    2013-04-01

    To investigate the use of radiofrequency (RF) gating in conjunction with a paramagnetic contrast agent to reduce the specific absorption rate (SAR) and increase the blood-myocardium contrast in balanced steady-state free precession (bSSFP) 3D cardiac cine. RF gating was implemented by synchronizing the RF-excitation with an external respiratory sensor (bellows), which could additionally be used for respiratory gating. For reference, respiratory-gated 3D cine images were acquired without RF gating. Free-breathing 3D cine images were acquired in eight healthy subjects before and after contrast injection (Gd-BOPTA) and compared to breath-hold 2D cine. RF-gated 3D cine reduced the SAR by nearly 40% without introducing significant artifacts while providing left ventricle (LV) measurements similar to those obtained with 2D cine. The contrast-to-noise ratio (CNR) was significantly higher for 3D cine compared to 2D cine, both before and after contrast injection; however, no statistically significant CNR increase was observed for the postcontrast 3D cine compared to the precontrast acquisitions. Respiratory-triggered RF gating significantly reduces SAR in 3D cine acquisitions, which may enable a more widespread clinical use of 3D cine. Furthermore, CNR of 3D bSSFP cine is higher than of 2D and administration of Gd-BOPTA does not improve the CNR of 3D cine. Copyright © 2012 Wiley Periodicals, Inc.

  16. The feasibility evaluation of Respiratory Gated radiation therapy simulation according to the Respiratory Training with lung cancer

    International Nuclear Information System (INIS)

    Hong, Mi Ran; Kim, Cheol Jong; Park, Soo Yeon; Choi, Jae Won; Pyo, Hong Ryeol

    2016-01-01

    To evaluate the usefulness of the breathing exercise,we analyzed the change in the RPM signal and the diaphragm image before 4D respiratory gated radiation therapy planning of lung cancer patients. The breathing training was enforced on 11 patients getting the 4D respiratory gated radiation therapy from April, 2016 until August. At the same time, RPM signal and diaphragm image was obtained respiration training total three steps in step 1 signal acquisition of free-breathing state, 2 steps respiratory signal acquisition through the guide of the respiratory signal, 3 steps, won the regular respiration signal to the description and repeat training. And then, acquired the minimum value, maximum value, average value, and a standard deviation of the inspiration and expiration in RPM signal and diaphragm image in each steps. Were normalized by the value of the step 1, to convert the 2,3 steps to the other distribution ratio (%), by evaluating the change in the interior of the respiratory motion of the patient, it was evaluated breathing exercise usefulness of each patient. The mean value and the standard deviation of each step were obtained with the procedure 1 of the RPM signal and the diaphragm amplitude as a 100% reference. In the RPM signal, the amplitudes and standard deviations of four patients (36.4%, eleven) decreased by 18.1%, 27.6% on average in 3 steps, and 2 patients (18.2%, 11 people) had standard deviation, It decreased by an average of 36.5%. Meanwhile, the other four patients (36.4%, eleven) decreased by an average of only amplitude 13.1%. In Step 3, the amplitude of the diaphragm image decreased by 30% on average of 9 patients (81.8%, 11 people), and the average of 2 patients (18.2%, 11 people) increased by 7.3%. However, the amplitudes of RPM signals and diaphragm image in 3 steps were reduced by 52.6% and 42.1% on average from all patients, respectively, compared to the 2 steps. Relationship between RPM signal and diaphragm image amplitude difference

  17. The feasibility evaluation of Respiratory Gated radiation therapy simulation according to the Respiratory Training with lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Mi Ran; Kim, Cheol Jong; Park, Soo Yeon; Choi, Jae Won; Pyo, Hong Ryeol [Dept. of Radiation Oncology, Samsung Medical Center, Seoul (Korea, Republic of)

    2016-12-15

    To evaluate the usefulness of the breathing exercise,we analyzed the change in the RPM signal and the diaphragm image before 4D respiratory gated radiation therapy planning of lung cancer patients. The breathing training was enforced on 11 patients getting the 4D respiratory gated radiation therapy from April, 2016 until August. At the same time, RPM signal and diaphragm image was obtained respiration training total three steps in step 1 signal acquisition of free-breathing state, 2 steps respiratory signal acquisition through the guide of the respiratory signal, 3 steps, won the regular respiration signal to the description and repeat training. And then, acquired the minimum value, maximum value, average value, and a standard deviation of the inspiration and expiration in RPM signal and diaphragm image in each steps. Were normalized by the value of the step 1, to convert the 2,3 steps to the other distribution ratio (%), by evaluating the change in the interior of the respiratory motion of the patient, it was evaluated breathing exercise usefulness of each patient. The mean value and the standard deviation of each step were obtained with the procedure 1 of the RPM signal and the diaphragm amplitude as a 100% reference. In the RPM signal, the amplitudes and standard deviations of four patients (36.4%, eleven) decreased by 18.1%, 27.6% on average in 3 steps, and 2 patients (18.2%, 11 people) had standard deviation, It decreased by an average of 36.5%. Meanwhile, the other four patients (36.4%, eleven) decreased by an average of only amplitude 13.1%. In Step 3, the amplitude of the diaphragm image decreased by 30% on average of 9 patients (81.8%, 11 people), and the average of 2 patients (18.2%, 11 people) increased by 7.3%. However, the amplitudes of RPM signals and diaphragm image in 3 steps were reduced by 52.6% and 42.1% on average from all patients, respectively, compared to the 2 steps. Relationship between RPM signal and diaphragm image amplitude difference

  18. Technical Report: TG-142 compliant and comprehensive quality assurance tests for respiratory gating

    Energy Technology Data Exchange (ETDEWEB)

    Woods, Kyle [Department of Radiation Oncology, Ohio State University, Columbus, Ohio 43210 (United States); Rong, Yi, E-mail: yrong@ucdavis.edu [Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, California 95817 (United States)

    2015-11-15

    Purpose: To develop and establish a comprehensive gating commissioning and quality assurance procedure in compliance with TG-142. Methods: Eight Varian TrueBeam Linacs were used for this study. Gating commissioning included an end-to-end test and baseline establishment. The end-to-end test was performed using a CIRS dynamic thoracic phantom with a moving cylinder inside the lung, which was used for carrying both optically simulated luminescence detectors (OSLDs) and Gafchromic EBT2 films while the target is moving, for a point dose check and 2D profile check. In addition, baselines were established for beam-on temporal delay and calibration of the surrogate, for both megavoltage (MV) and kilovoltage (kV) beams. A motion simulation device (MotionSim) was used to provide periodic motion on a platform, in synchronizing with a surrogate motion. The overall accuracy and uncertainties were analyzed and compared. Results: The OSLD readings were within 5% compared to the planned dose (within measurement uncertainty) for both phase and amplitude gated deliveries. Film results showed less than 3% agreement to the predicted dose with a standard sinusoid motion. The gate-on temporal accuracy was averaged at 139 ± 10 ms for MV beams and 92 ± 11 ms for kV beams. The temporal delay of the surrogate motion depends on the motion speed and was averaged at 54.6 ± 3.1 ms for slow, 24.9 ± 2.9 ms for intermediate, and 23.0 ± 20.1 ms for fast speed. Conclusions: A comprehensive gating commissioning procedure was introduced for verifying the output accuracy and establishing the temporal accuracy baselines with respiratory gating. The baselines are needed for routine quality assurance tests, as suggested by TG-142.

  19. Technical Report: TG-142 compliant and comprehensive quality assurance tests for respiratory gating

    International Nuclear Information System (INIS)

    Woods, Kyle; Rong, Yi

    2015-01-01

    Purpose: To develop and establish a comprehensive gating commissioning and quality assurance procedure in compliance with TG-142. Methods: Eight Varian TrueBeam Linacs were used for this study. Gating commissioning included an end-to-end test and baseline establishment. The end-to-end test was performed using a CIRS dynamic thoracic phantom with a moving cylinder inside the lung, which was used for carrying both optically simulated luminescence detectors (OSLDs) and Gafchromic EBT2 films while the target is moving, for a point dose check and 2D profile check. In addition, baselines were established for beam-on temporal delay and calibration of the surrogate, for both megavoltage (MV) and kilovoltage (kV) beams. A motion simulation device (MotionSim) was used to provide periodic motion on a platform, in synchronizing with a surrogate motion. The overall accuracy and uncertainties were analyzed and compared. Results: The OSLD readings were within 5% compared to the planned dose (within measurement uncertainty) for both phase and amplitude gated deliveries. Film results showed less than 3% agreement to the predicted dose with a standard sinusoid motion. The gate-on temporal accuracy was averaged at 139 ± 10 ms for MV beams and 92 ± 11 ms for kV beams. The temporal delay of the surrogate motion depends on the motion speed and was averaged at 54.6 ± 3.1 ms for slow, 24.9 ± 2.9 ms for intermediate, and 23.0 ± 20.1 ms for fast speed. Conclusions: A comprehensive gating commissioning procedure was introduced for verifying the output accuracy and establishing the temporal accuracy baselines with respiratory gating. The baselines are needed for routine quality assurance tests, as suggested by TG-142

  20. Real-time system for respiratory-cardiac gating in positron tomography

    International Nuclear Information System (INIS)

    Klein, G.J.; Reutter, B.W.; Ho, M.H.; Huesman, R.H.; Reed, J.H.

    1998-01-01

    A Macintosh-based signal processing system has been developed to support simultaneous respiratory and cardiac gating on the ECAT EXACT HR PET scanner. Using the Lab-View real-time software environment, the system reads analog inputs from a pneumatic respiratory bellows and an EGG monitor to compute an appropriate histogram memory location for the PET data. Respiratory state is determined by the bellows signal amplitude; cardiac state is based on the time since the last R-wave. These two states are used in a 2D lookup table to determine a combined respiratory-cardiac state. A 4-bit address encoding the selected histogram is directed from the system to the ECAT scanner, which dynamically switches the destination of tomograph events as respiratory-cardiac state changes. to Test the switching efficiency of the combined Macintosh/ECAT system, a rotating emission phantom was built. Acquisitions with 25 msec states while the phantom was rotating at 240 rpm demonstrate the system could effectively stop motion at this rate, with approximately 5 msec switching time between states

  1. Influence of Respiratory Gating, Image Filtering, and Animal Positioning on High-Resolution Electrocardiography-Gated Murine Cardiac Single-Photon Emission Computed Tomography

    Directory of Open Access Journals (Sweden)

    Chao Wu

    2015-01-01

    Full Text Available Cardiac parameters obtained from single-photon emission computed tomographic (SPECT images can be affected by respiratory motion, image filtering, and animal positioning. We investigated the influence of these factors on ultra-high-resolution murine myocardial perfusion SPECT. Five mice were injected with 99m technetium (99mTc-tetrofosmin, and each was scanned in supine and prone positions in a U-SPECT-II scanner with respiratory and electrocardiographic (ECG gating. ECG-gated SPECT images were created without applying respiratory motion correction or with two different respiratory motion correction strategies. The images were filtered with a range of three-dimensional gaussian kernels, after which end-diastolic volumes (EDVs, end-systolic volumes (ESVs, and left ventricular ejection fractions were calculated. No significant differences in the measured cardiac parameters were detected when any strategy to reduce or correct for respiratory motion was applied, whereas big differences (> 5% in EDV and ESV were found with regard to different positioning of animals. A linear relationship (p < .001 was found between the EDV or ESV and the kernel size of the gaussian filter. In short, respiratory gating did not significantly affect the cardiac parameters of mice obtained with ultra-high-resolution SPECT, whereas the position of the animals and the image filters should be the same in a comparative study with multiple scans to avoid systematic differences in measured cardiac parameters.

  2. SU-E-T-217: Intrinsic Respiratory Gating in Small Animal CT

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y; Smith, M; Mistry, N [University of Maryland School of Medicine, Baltimore, MD (United States)

    2014-06-01

    Purpose: Preclinical animal models of lung cancer can provide a controlled test-bed for testing dose escalation or function-based-treatment-planning studies. However, to extract lung function, i.e. ventilation, one needs to be able to image the lung at different phases of ventilation (in-hale / ex-hale). Most respiratory-gated imaging using micro-CT involves using an external ventilator and surgical intervention limiting the utility in longitudinal studies. A new intrinsic respiratory retrospective gating method was developed and tested in mice. Methods: A fixed region of interest (ROI) that covers the diaphragm was selected on all projection images to estimate the mean intensity (M). The mean intensity depends on the projection angle and diaphragm position. A 3-point moving average (A) of consecutive M values: Mpre, Mcurrent and Mpost, was calculated to be subtracted from Mcurrent. A fixed threshold was used to enable amplitude based sorting into 4 different phases of respiration. Images at full-inhale and end-exhale phases of respiration were reconstructed using the open source OSCaR. Lung volumes estimated at the 2 phases of respiration were validated against literature values. Results: Intrinsic retrospective gating was accomplished without the use of any external breathing waveform. While projection images were acquired at 360 different angles. Only 138 and 104 projections were used to reconstruct images at full-inhale and end-exhale. This often results in non-uniform under-sampled angular projections leading to some minor streaking artifacts. The calculated expiratory, inspiratory and tidal lung volumes correlated well with the values known from the literature. Conclusion: Our initial result demonstrates an intrinsic gating method that is suitable for flat panel cone beam small animal CT systems. Reduction in streaking artifacts can be accomplished by oversampling the data or using iterative reconstruction methods. This initial experience will enable

  3. Main technical aspects and clinical benefits of respiratory Gating for radiotherapy of lung neoplasm

    International Nuclear Information System (INIS)

    Benites, Rafaela Freitas Oliveira

    2016-01-01

    The concern with the irradiation of lung tumors is that many of them can move along the breathing, which can cause problems in defining accurately the target and increases the irradiation of normal tissues. The objectives are to present the 4D CT principles, image acquisition, reconstruction and application in planning of the radiotherapy. It justifies the quick implantation, improvements in acquisition and images, the possibility in quantify the tumor movement, verifying strategies and delivery treatment. It's concluded that the toxicity risk is reduced with the respiratory gating, and the results suggests that the closed RT will be of clinical relevance. (author)

  4. Respiratory-Gated Positron Emission Tomography and Breath-Hold Computed Tomography Coupling to Reduce the Influence of Respiratory Motion: Methodology and Feasibility

    International Nuclear Information System (INIS)

    Daouk, J.; Fin, L.; Bailly, P.; Meyer, M.E.

    2009-01-01

    Background: Respiratory motion causes uptake in positron emission tomography (PET) images of chest and abdominal structures to be blurred and reduced in intensity. Purpose: To compare two respiratory-gated PET binning methods (based on frequency and amplitude analyses of the respiratory signal) and to propose a 'BH-based' method based on an additional breath-hold computed tomography (CT) acquisition. Material and Methods: Respiratory-gated PET consists in list-mode (LM) acquisition with simultaneous respiratory signal recording. A phantom study featured rectilinear movement of a 0.5-ml sphere filled with 18 F-fluorodeoxyglucose ( 18 F-FDG) solution, placed in a radioactive background (sphere-to-background contrast 6:1). Two patients were also examined. Three figures of merit were calculated: the target-to-background ratio profile (TBRP) in the axial direction through the uptake (i.e., the sphere or lesion), full-width-at-half-maximum (FWHM) values, and maximized standard uptake values (SUVmax). Results: In the phantom study, the peak TBRP was 0.9 for non-gated volume, 1.83 for BH-based volume, and varied between 1.13 and 1.73 for Freq-based volumes and between 1.34 and 1.66 for Amp-based volumes. A reference volume (REF-static) was also acquired for the phantom (in a static, 'expiratory' state), with a peak TBRP at 1.88. TBRPs were computed for patient data, with higher peak values for all gated volumes than for non-gated volumes. Conclusion: Respiratory-gated PET acquisition reduces the blurring effect and increases image contrast. However, Freq-based and Amp-based volumes are still influenced by inappropriate attenuation correction and misregistration of mobile lesions on CT images. The proposed BH-based method both reduces motion artifacts and improves PET-CT registration

  5. Visual and Quantitative Analysis Methods of Respiratory Patterns for Respiratory Gated PET/CT.

    Science.gov (United States)

    Son, Hye Joo; Jeong, Young Jin; Yoon, Hyun Jin; Park, Jong-Hwan; Kang, Do-Young

    2016-01-01

    We integrated visual and quantitative methods for analyzing the stability of respiration using four methods: phase space diagrams, Fourier spectra, Poincaré maps, and Lyapunov exponents. Respiratory patterns of 139 patients were grouped based on the combination of the regularity of amplitude, period, and baseline positions. Visual grading was done by inspecting the shape of diagram and classified into two states: regular and irregular. Quantitation was done by measuring standard deviation of x and v coordinates of Poincaré map (SD x , SD v ) or the height of the fundamental peak ( A 1 ) in Fourier spectrum or calculating the difference between maximal upward and downward drift. Each group showed characteristic pattern on visual analysis. There was difference of quantitative parameters (SD x , SD v , A 1 , and MUD-MDD) among four groups (one way ANOVA, p = 0.0001 for MUD-MDD, SD x , and SD v , p = 0.0002 for A 1 ). In ROC analysis, the cutoff values were 0.11 for SD x (AUC: 0.982, p quantitative indices of respiratory stability and determining quantitative cutoff value for differentiating regular and irregular respiration.

  6. A contactless approach for respiratory gating in PET using continuous-wave radar

    Energy Technology Data Exchange (ETDEWEB)

    Ersepke, Thomas, E-mail: Thomas.Ersepke@rub.de; Büther, Florian; Heß, Mirco [European Institute for Molecular Imaging, University of Münster, Münster 48149 (Germany); Schäfers, Klaus P. [European Institute for Molecular Imaging, University of Münster, Münster 48149, Germany and DFG EXC 1003, Cluster of Excellence ‘Cells in Motion,’ Münster 48149 (Germany)

    2015-08-15

    Purpose: Respiratory gating is commonly used to reduce motion artifacts in positron emission tomography (PET). Clinically established methods for respiratory gating in PET require contact to the patient or a direct optical line between the sensor and the patient’s torso and time consuming preparation. In this work, a contactless method for capturing a respiratory signal during PET is presented based on continuous-wave radar. Methods: The proposed method relies on the principle of emitting an electromagnetic wave and detecting the phase shift of the reflected wave, modulated due to the respiratory movement of the patient’s torso. A 24 GHz carrier frequency was chosen allowing wave propagation through plastic and clothing with high reflections at the skin surface. A detector module and signal processing algorithms were developed to extract a quantitative respiratory signal. The sensor was validated using a high precision linear table. During volunteer measurements and [{sup 18}F] FDG PET scans, the radar sensor was positioned inside the scanner bore of a PET/computed tomography scanner. As reference, pressure belt (one volunteer), depth camera-based (two volunteers, two patients), and PET data-driven (six patients) signals were acquired simultaneously and the signal correlation was quantified. Results: The developed system demonstrated a high measurement accuracy for movement detection within the submillimeter range. With the proposed method, small displacements of 25 μm could be detected, not considerably influenced by clothing or blankets. From the patient studies, the extracted respiratory radar signals revealed high correlation (Pearson correlation coefficient) to those derived from the external pressure belt and depth camera signals (r = 0.69–0.99) and moderate correlation to those of the internal data-driven signals (r = 0.53–0.70). In some cases, a cardiac signal could be visualized, due to the representation of the mechanical heart motion on the skin

  7. A contactless approach for respiratory gating in PET using continuous-wave radar.

    Science.gov (United States)

    Ersepke, Thomas; Büther, Florian; Heß, Mirco; Schäfers, Klaus P

    2015-08-01

    Respiratory gating is commonly used to reduce motion artifacts in positron emission tomography (PET). Clinically established methods for respiratory gating in PET require contact to the patient or a direct optical line between the sensor and the patient's torso and time consuming preparation. In this work, a contactless method for capturing a respiratory signal during PET is presented based on continuous-wave radar. The proposed method relies on the principle of emitting an electromagnetic wave and detecting the phase shift of the reflected wave, modulated due to the respiratory movement of the patient's torso. A 24 GHz carrier frequency was chosen allowing wave propagation through plastic and clothing with high reflections at the skin surface. A detector module and signal processing algorithms were developed to extract a quantitative respiratory signal. The sensor was validated using a high precision linear table. During volunteer measurements and [(18)F] FDG PET scans, the radar sensor was positioned inside the scanner bore of a PET/computed tomography scanner. As reference, pressure belt (one volunteer), depth camera-based (two volunteers, two patients), and PET data-driven (six patients) signals were acquired simultaneously and the signal correlation was quantified. The developed system demonstrated a high measurement accuracy for movement detection within the submillimeter range. With the proposed method, small displacements of 25 μm could be detected, not considerably influenced by clothing or blankets. From the patient studies, the extracted respiratory radar signals revealed high correlation (Pearson correlation coefficient) to those derived from the external pressure belt and depth camera signals (r = 0.69-0.99) and moderate correlation to those of the internal data-driven signals (r = 0.53-0.70). In some cases, a cardiac signal could be visualized, due to the representation of the mechanical heart motion on the skin. Accurate respiratory signals were

  8. Utility estimation of the application of auditory-visual-tactile sense feedback in respiratory gated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jung Hun; KIm, Byeong Jin; Roh, Shi Won; Lee, Hyeon Chan; Jang, Hyeong Jun; Kim, Hoi Nam [Dept. of Radiation Oncology, Biomedical Engineering, Seoul St. Mary' s Hospital, Seoul (Korea, Republic of); Song, Jae Hoon [Dept. of Biomedical Engineering, Seoul St. Mary' s Hospital, Seoul (Korea, Republic of); Kim, Young Jae [Dept. of Radiological Technology, Gwang Yang Health Collage, Gwangyang (Korea, Republic of)

    2013-03-15

    The purpose of this study was to evaluate the possibility to optimize the gated treatment delivery time and maintenance of stable respiratory by the introduction of breath with the assistance of auditory-visual-tactile sense. The experimenter's respiration were measured by ANZAI 4D system. We obtained natural breathing signal, monitor-induced breathing signal, monitor and ventilator-induced breathing signal, and breath-hold signal using real time monitor during 10 minutes beam-on-time. In order to check the stability of respiratory signals distributed in each group were compared with means, standard deviation, variation value, beam{sub t}ime of the respiratory signal. The stability of each respiratory was measured in consideration of deviation change studied in each respiratory time lapse. As a result of an analysis of respiratory signal, all experimenters has showed that breathing signal used both Real time monitor and Ventilator was the most stable and shortest time. In this study, it was evaluated that respiratory gated radiation therapy with auditory-visual-tactual sense and without auditory-visual-tactual sense feedback. The study showed that respiratory gated radiation therapy delivery time could significantly be improved by the application of video feedback when this is combined with audio-tactual sense assistance. This delivery technique did prove its feasibility to limit the tumor motion during treatment delivery for all patients to a defined value while maintaining the accuracy and proved the applicability of the technique in a conventional clinical schedule.

  9. Utility estimation of the application of auditory-visual-tactile sense feedback in respiratory gated radiation therapy

    International Nuclear Information System (INIS)

    Jo, Jung Hun; KIm, Byeong Jin; Roh, Shi Won; Lee, Hyeon Chan; Jang, Hyeong Jun; Kim, Hoi Nam; Song, Jae Hoon; Kim, Young Jae

    2013-01-01

    The purpose of this study was to evaluate the possibility to optimize the gated treatment delivery time and maintenance of stable respiratory by the introduction of breath with the assistance of auditory-visual-tactile sense. The experimenter's respiration were measured by ANZAI 4D system. We obtained natural breathing signal, monitor-induced breathing signal, monitor and ventilator-induced breathing signal, and breath-hold signal using real time monitor during 10 minutes beam-on-time. In order to check the stability of respiratory signals distributed in each group were compared with means, standard deviation, variation value, beam t ime of the respiratory signal. The stability of each respiratory was measured in consideration of deviation change studied in each respiratory time lapse. As a result of an analysis of respiratory signal, all experimenters has showed that breathing signal used both Real time monitor and Ventilator was the most stable and shortest time. In this study, it was evaluated that respiratory gated radiation therapy with auditory-visual-tactual sense and without auditory-visual-tactual sense feedback. The study showed that respiratory gated radiation therapy delivery time could significantly be improved by the application of video feedback when this is combined with audio-tactual sense assistance. This delivery technique did prove its feasibility to limit the tumor motion during treatment delivery for all patients to a defined value while maintaining the accuracy and proved the applicability of the technique in a conventional clinical schedule

  10. Validation of a gating technique for radiotherapy treatment of injuries affected by respiratory motion; Validacion de una atecnica de gating para el tratamiento con radioterapia externa de lesiones afectadas por el movimiento respiratorio

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Ortega, J.; Castro Tejero, P.

    2011-07-01

    The use of gating techniques for the treatment of lesions that are involved respiratory motion may bring an increase in the dose administered. tumors and decreased the dose to adjacent healthy organs. In the study presented shows the steps taken to validate the respiratory gating technique using the RPM system (Real-time Position Management) from Varian. (Author)

  11. Quality assurance for respiratory-gated stereotactic body radiation therapy in lung using real-time position management system

    International Nuclear Information System (INIS)

    Nakaguchi, Yuji; Maruyama, Masato; Araki, Fujio; Kouno, Tomohiro

    2012-01-01

    In this study, we investigated comprehensive quality assurance (QA) for respiratory-gated stereotactic body radiation therapy (SBRT) in the lungs using a real-time position management system (RPM). By using the phantom study, we evaluated dose liberality and reproducibility, and dose distributions for low monitor unite (MU), and also checked the absorbed dose at isocenter and dose profiles for the respiratory-gated exposure using RPM. Furthermore, we evaluated isocenter dose and dose distributions for respiratory-gated SBRT plans in the lungs using RPM. The maximum errors for the dose liberality were 4% for 2 MU, 1% for 4-10 MU, and 0.5% for 15 MU and 20 MU. The dose reproducibility was 2% for 1 MU and within 0.1% for 5 MU or greater. The accuracy for dose distributions was within 2% for 2 MU or greater. The dose error along a central axis for respiratory cycles of 2, 4, and 6 sec was within 1%. As for geometric accuracy, 90% and 50% isodose areas for the respiratory-gated exposure became almost 1 mm and 2 mm larger than without gating, respectively. For clinical lung-SBRT plans, the point dose at isocenter agreed within 2.1% with treatment planning system (TPS). And the pass rates of all plans for TPS were more than 96% in the gamma analysis (3 mm/3%). The geometrical accuracy and the dose accuracy of TPS calculation algorithm are more important for the dose evaluation at penumbra region for respiratory-gated SBRT in lung using RPM. (author)

  12. Quantifying the impact of respiratory-gated 4D CT acquisition on thoracic image quality: A digital phantom study

    International Nuclear Information System (INIS)

    Bernatowicz, K.; Knopf, A.; Lomax, A.; Keall, P.; Kipritidis, J.; Mishra, P.

    2015-01-01

    Purpose: Prospective respiratory-gated 4D CT has been shown to reduce tumor image artifacts by up to 50% compared to conventional 4D CT. However, to date no studies have quantified the impact of gated 4D CT on normal lung tissue imaging, which is important in performing dose calculations based on accurate estimates of lung volume and structure. To determine the impact of gated 4D CT on thoracic image quality, the authors developed a novel simulation framework incorporating a realistic deformable digital phantom driven by patient tumor motion patterns. Based on this framework, the authors test the hypothesis that respiratory-gated 4D CT can significantly reduce lung imaging artifacts. Methods: Our simulation framework synchronizes the 4D extended cardiac torso (XCAT) phantom with tumor motion data in a quasi real-time fashion, allowing simulation of three 4D CT acquisition modes featuring different levels of respiratory feedback: (i) “conventional” 4D CT that uses a constant imaging and couch-shift frequency, (ii) “beam paused” 4D CT that interrupts imaging to avoid oversampling at a given couch position and respiratory phase, and (iii) “respiratory-gated” 4D CT that triggers acquisition only when the respiratory motion fulfills phase-specific displacement gating windows based on prescan breathing data. Our framework generates a set of ground truth comparators, representing the average XCAT anatomy during beam-on for each of ten respiratory phase bins. Based on this framework, the authors simulated conventional, beam-paused, and respiratory-gated 4D CT images using tumor motion patterns from seven lung cancer patients across 13 treatment fractions, with a simulated 5.5 cm 3 spherical lesion. Normal lung tissue image quality was quantified by comparing simulated and ground truth images in terms of overall mean square error (MSE) intensity difference, threshold-based lung volume error, and fractional false positive/false negative rates. Results: Averaged

  13. Quantifying the impact of respiratory-gated 4D CT acquisition on thoracic image quality: A digital phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Bernatowicz, K., E-mail: kingab@student.ethz.ch; Knopf, A.; Lomax, A. [Center for Proton Therapy, Paul Scherrer Institute, Villigen PSI 5232, Switzerland and Department of Physics, ETH Zürich, Zürich 8092 (Switzerland); Keall, P.; Kipritidis, J., E-mail: john.kipritidis@sydney.edu.au [Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney, NSW 2006 (Australia); Mishra, P. [Brigham and Womens Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115 (United States)

    2015-01-15

    Purpose: Prospective respiratory-gated 4D CT has been shown to reduce tumor image artifacts by up to 50% compared to conventional 4D CT. However, to date no studies have quantified the impact of gated 4D CT on normal lung tissue imaging, which is important in performing dose calculations based on accurate estimates of lung volume and structure. To determine the impact of gated 4D CT on thoracic image quality, the authors developed a novel simulation framework incorporating a realistic deformable digital phantom driven by patient tumor motion patterns. Based on this framework, the authors test the hypothesis that respiratory-gated 4D CT can significantly reduce lung imaging artifacts. Methods: Our simulation framework synchronizes the 4D extended cardiac torso (XCAT) phantom with tumor motion data in a quasi real-time fashion, allowing simulation of three 4D CT acquisition modes featuring different levels of respiratory feedback: (i) “conventional” 4D CT that uses a constant imaging and couch-shift frequency, (ii) “beam paused” 4D CT that interrupts imaging to avoid oversampling at a given couch position and respiratory phase, and (iii) “respiratory-gated” 4D CT that triggers acquisition only when the respiratory motion fulfills phase-specific displacement gating windows based on prescan breathing data. Our framework generates a set of ground truth comparators, representing the average XCAT anatomy during beam-on for each of ten respiratory phase bins. Based on this framework, the authors simulated conventional, beam-paused, and respiratory-gated 4D CT images using tumor motion patterns from seven lung cancer patients across 13 treatment fractions, with a simulated 5.5 cm{sup 3} spherical lesion. Normal lung tissue image quality was quantified by comparing simulated and ground truth images in terms of overall mean square error (MSE) intensity difference, threshold-based lung volume error, and fractional false positive/false negative rates. Results

  14. Quantification of liver fat with respiratory-gated quantitative chemical shift encoded MRI.

    Science.gov (United States)

    Motosugi, Utaroh; Hernando, Diego; Bannas, Peter; Holmes, James H; Wang, Kang; Shimakawa, Ann; Iwadate, Yuji; Taviani, Valentina; Rehm, Jennifer L; Reeder, Scott B

    2015-11-01

    To evaluate free-breathing chemical shift-encoded (CSE) magnetic resonance imaging (MRI) for quantification of hepatic proton density fat-fraction (PDFF). A secondary purpose was to evaluate hepatic R2* values measured using free-breathing quantitative CSE-MRI. Fifty patients (mean age, 56 years) were prospectively recruited and underwent the following four acquisitions to measure PDFF and R2*; 1) conventional breath-hold CSE-MRI (BH-CSE); 2) respiratory-gated CSE-MRI using respiratory bellows (BL-CSE); 3) respiratory-gated CSE-MRI using navigator echoes (NV-CSE); and 4) single voxel MR spectroscopy (MRS) as the reference standard for PDFF. Image quality was evaluated by two radiologists. MRI-PDFF measured from the three CSE-MRI methods were compared with MRS-PDFF using linear regression. The PDFF and R2* values were compared using two one-sided t-test to evaluate statistical equivalence. There was no significant difference in the image quality scores among the three CSE-MRI methods for either PDFF (P = 1.000) or R2* maps (P = 0.359-1.000). Correlation coefficients (95% confidence interval [CI]) for the PDFF comparisons were 0.98 (0.96-0.99) for BH-, 0.99 (0.97-0.99) for BL-, and 0.99 (0.98-0.99) for NV-CSE. The statistical equivalence test revealed that the mean difference in PDFF and R2* between any two of the three CSE-MRI methods was less than ±1 percentage point (pp) and ±5 s(-1) , respectively (P liver PDFF and R2* and are as valid as the standard breath-hold technique. © 2015 Wiley Periodicals, Inc.

  15. SU-E-J-169: The Dosimetric and Temporal Effects of Respiratory-Gated Radiation Therapy in Lung Cancer Patients

    International Nuclear Information System (INIS)

    Rouabhi, O; Gross, B; Xia, J; Bayouth, J

    2015-01-01

    Purpose: To evaluate the dosimetric and temporal effects of high dose rate treatment mode for respiratory-gated radiation therapy in lung cancer patients. Methods: Treatment plans from five lung cancer patients (3 nongated (Group 1), 2 gated at 80EX-80IN (Group 2)) were retrospectively evaluated. The maximum tumor motions range from 6–12 mm. Using the same planning criteria, four new treatment plans, corresponding to four gating windows (20EX–20IN, 40EX–40IN, 60EX–60IN, and 80EX–80IN), were generated for each patient. Mean tumor dose (MTD), mean lung dose (MLD), and lung V20 were used to assess the dosimetric effects. A MATLAB algorithm was developed to compute treatment time by considering gantry rotation time, time to position collimator leaves, dose delivery time (scaled relative to the gating window), and communication overhead. Treatment delivery time for each plan was estimated using a 500 MU/min dose rate for the original plans and a 1500 MU/min dose rate for the gated plans. Results: Differences in MTD were less than 1Gy across plans for all five patients. MLD and lung V20 were on average reduced between −16.1% to −6.0% and −20.0% to −7.2%, respectively for non-gated plans when compared with the corresponding gated plans, and between − 5.8% to −4.2% and −7.0% to −5.4%, respectively for plans originally gated at 80EX–80IN when compared with the corresponding 20EX-20IN to 60EX– 60IN gated plans. Treatment delivery times of gated plans using high dose rate were reduced on average between −19.7% (−1.9min) to −27.2% (−2.7min) for originally non-gated plans and −15.6% (−0.9min) to −20.3% (−1.2min) for originally 80EX-80IN gated plans. Conclusion: Respiratory-gated radiation therapy in lung cancer patients can reduce lung toxicity, while maintaining tumor dose. Using a gated high-dose-rate treatment, delivery time comparable to non-gated normal-dose-rate treatment can be achieved. This research is supported by Siemens

  16. Respiratory motion management using audio-visual biofeedback for respiratory-gated radiotherapy of synchrotron-based pulsed heavy-ion beam delivery

    International Nuclear Information System (INIS)

    He, Pengbo; Ma, Yuanyuan; Huang, Qiyan; Yan, Yuanlin; Li, Qiang; Liu, Xinguo; Dai, Zhongying; Zhao, Ting; Fu, Tingyan; Shen, Guosheng

    2014-01-01

    Purpose: To efficiently deliver respiratory-gated radiation during synchrotron-based pulsed heavy-ion radiotherapy, a novel respiratory guidance method combining a personalized audio-visual biofeedback (BFB) system, breath hold (BH), and synchrotron-based gating was designed to help patients synchronize their respiratory patterns with synchrotron pulses and to overcome typical limitations such as low efficiency, residual motion, and discomfort. Methods: In-house software was developed to acquire body surface marker positions and display BFB, gating signals, and real-time beam profiles on a LED screen. Patients were prompted to perform short BHs or short deep breath holds (SDBH) with the aid of BFB following a personalized standard BH/SDBH (stBH/stSDBH) guiding curve or their own representative BH/SDBH (reBH/reSDBH) guiding curve. A practical simulation was performed for a group of 15 volunteers to evaluate the feasibility and effectiveness of this method. Effective dose rates (EDRs), mean absolute errors between the guiding curves and the measured curves, and mean absolute deviations of the measured curves were obtained within 10%–50% duty cycles (DCs) that were synchronized with the synchrotron’s flat-top phase. Results: All maneuvers for an individual volunteer took approximately half an hour, and no one experienced discomfort during the maneuvers. Using the respiratory guidance methods, the magnitude of residual motion was almost ten times less than during nongated irradiation, and increases in the average effective dose rate by factors of 2.39–4.65, 2.39–4.59, 1.73–3.50, and 1.73–3.55 for the stBH, reBH, stSDBH, and reSDBH guiding maneuvers, respectively, were observed in contrast with conventional free breathing-based gated irradiation, depending on the respiratory-gated duty cycle settings. Conclusions: The proposed respiratory guidance method with personalized BFB was confirmed to be feasible in a group of volunteers. Increased effective dose

  17. Respiratory motion management using audio-visual biofeedback for respiratory-gated radiotherapy of synchrotron-based pulsed heavy-ion beam delivery

    Energy Technology Data Exchange (ETDEWEB)

    He, Pengbo; Ma, Yuanyuan; Huang, Qiyan; Yan, Yuanlin [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China); School of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Qiang, E-mail: liqiang@impcas.ac.cn; Liu, Xinguo; Dai, Zhongying; Zhao, Ting; Fu, Tingyan; Shen, Guosheng [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-11-01

    Purpose: To efficiently deliver respiratory-gated radiation during synchrotron-based pulsed heavy-ion radiotherapy, a novel respiratory guidance method combining a personalized audio-visual biofeedback (BFB) system, breath hold (BH), and synchrotron-based gating was designed to help patients synchronize their respiratory patterns with synchrotron pulses and to overcome typical limitations such as low efficiency, residual motion, and discomfort. Methods: In-house software was developed to acquire body surface marker positions and display BFB, gating signals, and real-time beam profiles on a LED screen. Patients were prompted to perform short BHs or short deep breath holds (SDBH) with the aid of BFB following a personalized standard BH/SDBH (stBH/stSDBH) guiding curve or their own representative BH/SDBH (reBH/reSDBH) guiding curve. A practical simulation was performed for a group of 15 volunteers to evaluate the feasibility and effectiveness of this method. Effective dose rates (EDRs), mean absolute errors between the guiding curves and the measured curves, and mean absolute deviations of the measured curves were obtained within 10%–50% duty cycles (DCs) that were synchronized with the synchrotron’s flat-top phase. Results: All maneuvers for an individual volunteer took approximately half an hour, and no one experienced discomfort during the maneuvers. Using the respiratory guidance methods, the magnitude of residual motion was almost ten times less than during nongated irradiation, and increases in the average effective dose rate by factors of 2.39–4.65, 2.39–4.59, 1.73–3.50, and 1.73–3.55 for the stBH, reBH, stSDBH, and reSDBH guiding maneuvers, respectively, were observed in contrast with conventional free breathing-based gated irradiation, depending on the respiratory-gated duty cycle settings. Conclusions: The proposed respiratory guidance method with personalized BFB was confirmed to be feasible in a group of volunteers. Increased effective dose

  18. Motion management within two respiratory-gating windows: feasibility study of dual quasi-breath-hold technique in gated medical procedures

    International Nuclear Information System (INIS)

    Kim, Taeho; Kim, Siyong; Youn, Kaylin K; Park, Yang-Kyun; Keall, Paul; Lee, Rena

    2014-01-01

    A dual quasi-breath-hold (DQBH) technique is proposed for respiratory motion management (a hybrid technique combining breathing-guidance with breath-hold task in the middle). The aim of this study is to test a hypothesis that the DQBH biofeedback system improves both the capability of motion management and delivery efficiency. Fifteen healthy human subjects were recruited for two respiratory motion measurements (free breathing and DQBH biofeedback breathing for 15 min). In this study, the DQBH biofeedback system utilized the abdominal position obtained using an real-time position management (RPM) system (Varian Medical Systems, Palo Alto, USA) to audio-visually guide a human subject for 4 s breath-hold at EOI and 90% EOE (EOE 90% ) to improve delivery efficiency. We investigated the residual respiratory motion and the delivery efficiency (duty-cycle) of abdominal displacement within the gating window. The improvement of the abdominal motion reproducibility was evaluated in terms of cycle-to-cycle displacement variability, respiratory period and baseline drift. The DQBH biofeedback system improved the abdominal motion management capability compared to that with free breathing. With a phase based gating (mean ± std: 55  ±  5%), the averaged root mean square error (RMSE) of the abdominal displacement in the dual-gating windows decreased from 2.26 mm of free breathing to 1.16 mm of DQBH biofeedback (p-value = 0.007). The averaged RMSE of abdominal displacement over the entire respiratory cycles reduced from 2.23 mm of free breathing to 1.39 mm of DQBH biofeedback breathing in the dual-gating windows (p-value = 0.028). The averaged baseline drift dropped from 0.9 mm min −1 with free breathing to 0.09 mm min −1 with DQBH biofeedback (p-value = 0.048). The averaged duty-cycle with an 1 mm width of displacement bound increased from 15% of free breathing to 26% of DQBH biofeedback (p-value = 0.003). The study demonstrated that the DQBH

  19. SU-E-J-89: Motion Effects On Organ Dose in Respiratory Gated Stereotactic Body Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T; Zhu, L [Georgia Institute of Technology, Atlanta, GA (Georgia); Khan, M; Landry, J; Rajpara, R; Hawk, N [Emory University, Atlanta, GA (United States)

    2014-06-01

    Purpose: Existing reports on gated radiation therapy focus mainly on optimizing dose delivery to the target structure. This work investigates the motion effects on radiation dose delivered to organs at risk (OAR) in respiratory gated stereotactic body radiation therapy (SBRT). A new algorithmic tool of dose analysis is developed to evaluate the optimality of gating phase for dose sparing on OARs while ensuring adequate target coverage. Methods: Eight patients with pancreatic cancer were treated on a phase I prospective study employing 4DCT-based SBRT. For each patient, 4DCT scans are acquired and sorted into 10 respiratory phases (inhale-exhale- inhale). Treatment planning is performed on the average CT image. The average CT is spatially registered to other phases. The resultant displacement field is then applied on the plan dose map to estimate the actual dose map for each phase. Dose values of each voxel are fitted to a sinusoidal function. Fitting parameters of dose variation, mean delivered dose and optimal gating phase for each voxel over respiration cycle are mapped on the dose volume. Results: The sinusoidal function accurately models the dose change during respiratory motion (mean fitting error 4.6%). In the eight patients, mean dose variation is 3.3 Gy on OARs with maximum of 13.7 Gy. Two patients have about 100cm{sup 3} volumes covered by more than 5 Gy deviation. The mean delivered dose maps are similar to plan dose with slight deformation. The optimal gating phase highly varies across the patient, with phase 5 or 6 on about 60% of the volume, and phase 0 on most of the rest. Conclusion: A new algorithmic tool is developed to conveniently quantify dose deviation on OARs from plan dose during the respiratory cycle. The proposed software facilitates the treatment planning process by providing the optimal respiratory gating phase for dose sparing on each OAR.

  20. Dynamic respiratory gated 18FDG-PET of lung tumors - a feasibility study

    International Nuclear Information System (INIS)

    Skjei Knudtsen, Ingerid; Skretting, Arne; Roedal, Jan; Brustugun, Odd Terje; Helland, Aaslaug; Malinen, Eirik

    2011-01-01

    Background. 18 FDG-PET/CT imaging is well established for diagnosis and staging of lung tumors. However, more detailed information regarding the distribution of FDG within the tumor, also as a function of time after injection may be relevant. In this study we explore the feasibility of a combined dynamic and respiratory gated (DR) PET protocol. Material and methods. A DR FDG-PET protocol for a Siemens Biograph 16 PET/CT scanner was set up, allowing data acquisition from the time of FDG injection. Breath-hold (BH) respiratory gating was performed at four intervals over a total acquisition time of 50 minutes. Thus, the PET protocol provides both motion-free images and a spatiotemporal characterization of the glucose distribution in lung tumors. Software tools were developed in-house for tentative tumor segmentation and for extracting standard uptake values (SUVs) voxel by voxel, tumor volumes and SUV gradients in all directions. Results. Four pilot patients have been investigated with the DR PET protocol. The procedure was well tolerated by the patients. The BH images appeared sharper, and SUV max /SUV mean was higher, compared to free breathing (FB) images. Also, SUV gradients in the periphery of the tumor in the BH images were in general greater than or equal to the gradients in the FB PET images. Conclusion. The DR FDG-PET protocol is feasible and the BH images have a superior quality compared to the FB images. The protocol may also provide information of relevance for radiotherapy planning and follow-up. A patient trial is needed for assessing the clinical value of the imaging protocol

  1. Optimization of a retrospective technique for respiratory-gated high speed micro-CT of free-breathing rodents

    International Nuclear Information System (INIS)

    Ford, Nancy L; Wheatley, Andrew R; Holdsworth, David W; Drangova, Maria

    2007-01-01

    The objective of this study was to develop a technique for dynamic respiratory imaging using retrospectively gated high-speed micro-CT imaging of free-breathing mice. Free-breathing C57Bl6 mice were scanned using a dynamic micro-CT scanner, comprising a flat-panel detector mounted on a slip-ring gantry. Projection images were acquired over ten complete gantry rotations in 50 s, while monitoring the respiratory motion in synchrony with projection-image acquisition. Projection images belonging to a selected respiratory phase were retrospectively identified and used for 3D reconstruction. The effect of using fewer gantry rotations-which influences both image quality and the ability to quantify respiratory function-was evaluated. Images reconstructed using unique projections from six or more gantry rotations produced acceptable images for quantitative analysis of lung volume, CT density, functional residual capacity and tidal volume. The functional residual capacity (0.15 ± 0.03 mL) and tidal volumes (0.08 ± 0.03 mL) measured in this study agree with previously reported measurements made using prospectively gated micro-CT and at higher resolution (150 μm versus 90 μm voxel spacing). Retrospectively gated micro-CT imaging of free-breathing mice enables quantitative dynamic measurement of morphological and functional parameters in the mouse models of respiratory disease, with scan times as short as 30 s, based on the acquisition of projection images over six gantry rotations

  2. Optimization of a retrospective technique for respiratory-gated high speed micro-CT of free-breathing rodents

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Nancy L [Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada); Wheatley, Andrew R [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, PO Box 5015, London, Ontario N6A 5K8 (Canada); Holdsworth, David W [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, PO Box 5015, London, Ontario N6A 5K8 (Canada); Drangova, Maria [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, PO Box 5015, London, Ontario N6A 5K8 (Canada)

    2007-09-21

    The objective of this study was to develop a technique for dynamic respiratory imaging using retrospectively gated high-speed micro-CT imaging of free-breathing mice. Free-breathing C57Bl6 mice were scanned using a dynamic micro-CT scanner, comprising a flat-panel detector mounted on a slip-ring gantry. Projection images were acquired over ten complete gantry rotations in 50 s, while monitoring the respiratory motion in synchrony with projection-image acquisition. Projection images belonging to a selected respiratory phase were retrospectively identified and used for 3D reconstruction. The effect of using fewer gantry rotations-which influences both image quality and the ability to quantify respiratory function-was evaluated. Images reconstructed using unique projections from six or more gantry rotations produced acceptable images for quantitative analysis of lung volume, CT density, functional residual capacity and tidal volume. The functional residual capacity (0.15 {+-} 0.03 mL) and tidal volumes (0.08 {+-} 0.03 mL) measured in this study agree with previously reported measurements made using prospectively gated micro-CT and at higher resolution (150 {mu}m versus 90 {mu}m voxel spacing). Retrospectively gated micro-CT imaging of free-breathing mice enables quantitative dynamic measurement of morphological and functional parameters in the mouse models of respiratory disease, with scan times as short as 30 s, based on the acquisition of projection images over six gantry rotations.

  3. The correlation between internal and external markers for abdominal tumors: Implications for respiratory gating

    International Nuclear Information System (INIS)

    Gierga, David P.; Brewer, Johanna; Sharp, Gregory C.; Betke, Margrit; Willett, Christopher G.; Chen, George T.Y.

    2005-01-01

    Purpose: The correlation of the respiratory motion of external patient markers and abdominal tumors was examined. Data of this type are important for image-guided therapy techniques, such as respiratory gating, that monitor the movement of external fiducials. Methods and Materials: Fluoroscopy sessions for 4 patients with internal, radiopaque tumor fiducial clips were analyzed by computer vision techniques. The motion of the internal clips and the external markers placed on the patient's abdominal skin surface were quantified and correlated. Results: In general, the motion of the tumor and external markers were well correlated. The maximum amount of peak-to-peak craniocaudal tumor motion was 2.5 cm. The ratio of tumor motion to external-marker motion ranged from 0.85 to 7.1. The variation in tumor position for a given external-marker position ranged from 2 to 9 mm. The period of the breathing cycle ranged from 2.7 to 4.5 seconds, and the frequency patterns for both the tumor and the external markers were similar. Conclusions: Although tumor motion generally correlated well with external fiducial marker motion, relatively large underlying tumor motion can occur compared with external-marker motion and variations in the tumor position for a given marker position. Treatment margins should be determined on the basis of a detailed understanding of tumor motion, as opposed to relying only on external-marker information

  4. Improved attenuation correction for respiratory gated PET/CT with extended-duration cine CT: a simulation study

    Science.gov (United States)

    Zhang, Ruoqiao; Alessio, Adam M.; Pierce, Larry A.; Byrd, Darrin W.; Lee, Tzu-Cheng; De Man, Bruno; Kinahan, Paul E.

    2017-03-01

    Due to the wide variability of intra-patient respiratory motion patterns, traditional short-duration cine CT used in respiratory gated PET/CT may be insufficient to match the PET scan data, resulting in suboptimal attenuation correction that eventually compromises the PET quantitative accuracy. Thus, extending the duration of cine CT can be beneficial to address this data mismatch issue. In this work, we propose to use a long-duration cine CT for respiratory gated PET/CT, whose cine acquisition time is ten times longer than a traditional short-duration cine CT. We compare the proposed long-duration cine CT with the traditional short-duration cine CT through numerous phantom simulations with 11 respiratory traces measured during patient PET/CT scans. Experimental results show that, the long-duration cine CT reduces the motion mismatch between PET and CT by 41% and improves the overall reconstruction accuracy by 42% on average, as compared to the traditional short-duration cine CT. The long-duration cine CT also reduces artifacts in PET images caused by misalignment and mismatch between adjacent slices in phase-gated CT images. The improvement in motion matching between PET and CT by extending the cine duration depends on the patient, with potentially greater benefits for patients with irregular breathing patterns or larger diaphragm movements.

  5. Clinical application of MRI-respiratory gating technology in the evaluation of children with obstructive sleep apnea hypopnea syndrome.

    Science.gov (United States)

    Zeng, Guohui; Teng, Yaoshu; Zhu, Jin; Zhu, Darong; Yang, Bin; Hu, Linping; Chen, Manman; Fu, Xiao

    2018-01-01

    The objective of the present study was to investigate the clinical application of magnetic resonance imaging (MRI)-respiratory gating technology for assessing illness severity in children with obstructive sleep apnea hypopnea syndrome (OSAHS).MRI-respiratory gating technology was used to scan the nasopharyngeal cavities of 51 children diagnosed with OSAHS during 6 respiratory phases. Correlations between the ratio of the area of the adenoid to the area of the nasopalatine pharyngeal cavity (Sa/Snp), with the main indexes of polysomnography (PSG), were analyzed. Receiver operator characteristic (ROC) curve and Kappa analysis were used to determine the diagnostic accuracy of Sa/Snp in pediatric OSAHS.The Sa/Snp was positively correlated with the apnea hypopnea index (AHI) (P children. Consistency analysis with the AHI showed a diagnosis accordance rate of 96.0% in severe pediatric OSAHS and 96.2% in slight-moderate pediatric OSAHS (Kappa = 0.922, P children with adenoidal hypertrophy was greatest at the end-expiration phase during sleep. The end-expiratory Sa/Snp obtained by a combination of MRI and respiratory gating technology has potential as an important imaging index for diagnosing and evaluating severity in pediatric OSAHS.

  6. Impact of a new respiratory amplitude-based gating technique in evaluation of upper abdominal PET lesions

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Gucht, Axel, E-mail: axel.vandergucht@gmail.com [Department of Nuclear Medicine, Centre Hospitalier Princesse Grace, Monaco (Monaco); Serrano, Benjamin [Department of Medical Physics, Centre Hospitalier Princesse Grace, Monaco (Monaco); Hugonnet, Florent; Paulmier, Benoît [Department of Nuclear Medicine, Centre Hospitalier Princesse Grace, Monaco (Monaco); Garnier, Nicolas [Department of Medical Physics, Centre Hospitalier Princesse Grace, Monaco (Monaco); Faraggi, Marc [Department of Nuclear Medicine, Centre Hospitalier Princesse Grace, Monaco (Monaco)

    2014-03-15

    PET acquisition requires several minutes which can lead to respiratory motion blurring, to increase partial volume effect and SUV under-estimation. To avoid these artifacts, conventional 10-min phase-based respiratory gating (PBRG) can be performed but is time-consuming and difficult with a non-compliant patient. We evaluated an automatic amplitude-based gating method (AABG) which keeps 35% of the counts at the end of expiration to minimize respiratory motion. We estimated the impact of AABG on upper abdominal lesion detectability, quantification and patient management. Methods: We consecutively included 31 patients (82 hepatic and 25 perihepatic known lesions). Each patient underwent 3 acquisitions on a Siemens Biograph mCT (4 rings and time-of-flight): a standard free-breathing whole-body (SWB, 5–7 steps/2.5 min per step, 3.3 ± 0.4 MBq/kg of 18F-FDG), a 10-min PBRG with six bins and a 5-min AABG method. All gated acquisitions were performed with an ANZAI respiratory gating system. SUV{sub max} and target to background ratio (TBR, defined as the maximum SUV of the lesion divided by the mean SUV of a region of interest drawn in healthy liver) were compared. Results: All 94 lesions in SWB images were detected in the gated images. 10-min PBRG and 5-min AABG acquisitions respectively revealed 9 and 13 new lesions and relocated 7 and 8 lesions. Four lesions revealed by 5-min AABG were missed by 10-min PBRG in 3 non-compliant patients. Both gated methods failed to relocate 2 lesions seen on SWB acquisition. Compared to SWB, TBR increased significantly with 10-min PBRG and with 5-min AABG (respectively 41 ± 59%, p = 4.10–3 and 66 ± 75%, p = 6.10–5) whereas SUV{sub max} did not (respectively 14 ± 43%, p = 0.29 with 10-min PBRG, and 24 ± 46%, p = 0.11 with 5-min AABG). Conclusion: The AABG is a fast and a user-friendly respiratory gating method to increase detectability and quantification of upper abdominal lesions compared to the conventional PBRG procedure and

  7. MO-FG-BRA-08: Swarm Intelligence-Based Personalized Respiratory Gating in Lung SAbR

    Energy Technology Data Exchange (ETDEWEB)

    Modiri, A; Sabouri, P; Sawant, A [University of Maryland in Baltimore, Baltimore, MD (United States); Gu, X; Timmerman, R [University of Texas Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: Respiratory gating is widely deployed as a clinical motion-management strategy in lung radiotherapy. In conventional gating, the beam is turned on during a pre-determined phase window; typically, around end-exhalation. In this work, we challenge the notion that end-exhalation is always the optimal gating phase. Specifically, we use a swarm-intelligence-based, inverse planning approach to determine the optimal respiratory phase and MU for each beam with respect to (i) the state of the anatomy at each phase and (ii) the time spent in that state, estimated from long-term monitoring of the patient’s breathing motion. Methods: In a retrospective study of five lung cancer patients, we compared the dosimetric performance of our proposed personalized gating (PG) with that of conventional end-of-exhale gating (CEG) and a previously-developed, fully 4D-optimized plan (combined with MLC tracking delivery). For each patient, respiratory phase probabilities (indicative of the time duration of the phase) were estimated over 2 minutes from lung tumor motion traces recorded previously using the Synchrony system (Accuray Inc.). Based on this information, inverse planning optimization was performed to calculate the optimal respiratory gating phase and MU for each beam. To ensure practical deliverability, each PG beam was constrained to deliver the assigned MU over a time duration comparable to that of CEG delivery. Results: Maximum OAR sparing for the five patients achieved by the PG and the 4D plans compared to CEG plans was: Esophagus Dmax [PG:57%, 4D:37%], Heart Dmax [PG:71%, 4D:87%], Spinal cord Dmax [PG:18%, 4D:68%] and Lung V13 [PG:16%, 4D:31%]. While patients spent the most time in exhalation, the PG-optimization chose end-exhale only for 28% of beams. Conclusion: Our novel gating strategy achieved significant dosimetric improvements over conventional gating, and approached the upper limit represented by fully 4D optimized planning while being significantly simpler

  8. MO-FG-BRA-08: Swarm Intelligence-Based Personalized Respiratory Gating in Lung SAbR

    International Nuclear Information System (INIS)

    Modiri, A; Sabouri, P; Sawant, A; Gu, X; Timmerman, R

    2016-01-01

    Purpose: Respiratory gating is widely deployed as a clinical motion-management strategy in lung radiotherapy. In conventional gating, the beam is turned on during a pre-determined phase window; typically, around end-exhalation. In this work, we challenge the notion that end-exhalation is always the optimal gating phase. Specifically, we use a swarm-intelligence-based, inverse planning approach to determine the optimal respiratory phase and MU for each beam with respect to (i) the state of the anatomy at each phase and (ii) the time spent in that state, estimated from long-term monitoring of the patient’s breathing motion. Methods: In a retrospective study of five lung cancer patients, we compared the dosimetric performance of our proposed personalized gating (PG) with that of conventional end-of-exhale gating (CEG) and a previously-developed, fully 4D-optimized plan (combined with MLC tracking delivery). For each patient, respiratory phase probabilities (indicative of the time duration of the phase) were estimated over 2 minutes from lung tumor motion traces recorded previously using the Synchrony system (Accuray Inc.). Based on this information, inverse planning optimization was performed to calculate the optimal respiratory gating phase and MU for each beam. To ensure practical deliverability, each PG beam was constrained to deliver the assigned MU over a time duration comparable to that of CEG delivery. Results: Maximum OAR sparing for the five patients achieved by the PG and the 4D plans compared to CEG plans was: Esophagus Dmax [PG:57%, 4D:37%], Heart Dmax [PG:71%, 4D:87%], Spinal cord Dmax [PG:18%, 4D:68%] and Lung V13 [PG:16%, 4D:31%]. While patients spent the most time in exhalation, the PG-optimization chose end-exhale only for 28% of beams. Conclusion: Our novel gating strategy achieved significant dosimetric improvements over conventional gating, and approached the upper limit represented by fully 4D optimized planning while being significantly simpler

  9. Free-breathing steady-state free precession cine cardiac magnetic resonance with respiratory navigator gating.

    Science.gov (United States)

    Moghari, Mehdi H; Komarlu, Rukmini; Annese, David; Geva, Tal; Powell, Andrew J

    2015-04-01

    To develop and validate a respiratory motion compensation method for free-breathing cardiac cine imaging. A free-breathing navigator-gated cine steady-state free precession acquisition (Cine-Nav) was developed which preserves the equilibrium state of the net magnetization vector, maintains the high spatial and temporal resolutions of standard breath-hold (BH) acquisition, and images entire cardiac cycle. Cine image data is accepted only from cardiac cycles occurring entirely during end-expiration. Prospective validation was performed in 10 patients by obtaining in each three complete ventricular image stacks with different respiratory motion compensation approaches: (1) BH, (2) free-breathing with 3 signal averages (3AVG), and (3) free-breathing with Cine-Nav. The subjective image quality score (1 = worst, 4 = best) for Cine-Nav (3.8 ± 0.4) was significantly better than for 3AVG (2.2 ± 0.5, P = 0.002), and similar to BH (4.0 ± 0.0, P = 0.13). The blood-to-myocardium contrast ratio for Cine-Nav (6.3 ± 1.5) was similar to BH (5.9 ± 1.6, P = 0.52) and to 3AVG (5.6 ± 2.5, P = 0.43). There were no significant differences between Cine-Nav and BH for the ventricular volumes and mass. In contrast, there were significant differences between 3AVG and BH in all of these measurements but right ventricular mass. Free-breathing cine imaging with Cine-Nav yielded comparable image quality and ventricular measurements to BH, and was superior to 3AVG. © 2014 Wiley Periodicals, Inc.

  10. SU-G-JeP3-09: Tumor Location Prediction Using Natural Respiratory Volume for Respiratory Gated Radiation Therapy (RGRT): System Verification Study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M; Jung, J; Yoon, D; Shin, H; Kim, S; Suh, T [The catholic university of Korea, Seoul (Korea, Republic of)

    2016-06-15

    Purpose: Respiratory gated radiation therapy (RGRT) gives accurate results when a patient’s breathing is stable and regular. Thus, the patient should be fully aware during respiratory pattern training before undergoing the RGRT treatment. In order to bypass the process of respiratory pattern training, we propose a target location prediction system for RGRT that uses only natural respiratory volume, and confirm its application. Methods: In order to verify the proposed target location prediction system, an in-house phantom set was used. This set involves a chest phantom including target, external markers, and motion generator. Natural respiratory volume signals were generated using the random function in MATLAB code. In the chest phantom, the target takes a linear motion based on the respiratory signal. After a four-dimensional computed tomography (4DCT) scan of the in-house phantom, the motion trajectory was derived as a linear equation. The accuracy of the linear equation was compared with that of the motion algorithm used by the operating motion generator. In addition, we attempted target location prediction using random respiratory volume values. Results: The correspondence rate of the linear equation derived from the 4DCT images with the motion algorithm of the motion generator was 99.41%. In addition, the average error rate of target location prediction was 1.23% for 26 cases. Conclusion: We confirmed the applicability of our proposed target location prediction system for RGRT using natural respiratory volume. If additional clinical studies can be conducted, a more accurate prediction system can be realized without requiring respiratory pattern training.

  11. SU-D-12A-05: Iterative Reconstruction Techniques to Enable Intrinsic Respiratory Gated CT in Mice

    Energy Technology Data Exchange (ETDEWEB)

    Sun, T; Sun, N; Tan, S [Huazhong University of Science and Technology, Wuhan, Hubei (China); Liu, Y; Mistry, N [University of Maryland School of Medicine, Baltimore, MD (United States)

    2014-06-01

    Purpose: Longitudinal studies of lung function in mice need the ability to image different phases of ventilation in free-breathing mice using retrospective gating. However, retrospective gating often produces under-sampled and uneven angular samples, resulting in severe reconstruction artifacts when using traditional FDK based reconstruction algorithms. We wanted to demonstrate the utility of iterative reconstruction method to enable intrinsic respiratory gating in small-animal CT. Methods: Free-breathing mice were imaged using a Siemens Inveon PET/micro-CT system. Evenly distributed projection images were acquired at 360 angles. Retrospective respiratory gating was performed using an intrinsic marker based on the average intensity in a region covering the diaphragm. Projections were classified into 4 and 6 phases (finer temporal resolution) resulting in 138 and 67 projections respectively. Reconstruction was carried out using 3 Methods: conventional FDK, iterative penalized least-square (PWLS) with total variation (TV), and PWLS with edge-preserving penalty. The performance of the methods was compared using contrast-to-noise (CNR) in a region of interest (ROI). Line profile through a specific region was plotted to evaluate the preserving of edges. Results: In both the cases with 4 and 6 phases, inadequate and non-uniform angular sampling results in artifacts using conventional FDK. However, such artifacts are minimized using both the iterative methods. Using both 4 and 6 phases, the iterative techniques outperformed FDK in terms of CNR and maintaining sharp edges. This is further evidenced especially with increased artifacts using FDK for 6 phases. Conclusion: This work indicates fewer artifacts and better image details can be achieved with iterative reconstruction methods in non-uniform under-sampled reconstruction. Using iterative methods can enable free-breathing intrinsic respiratory gating in small-animal CT. Further studies are needed to compare the

  12. Determining the most stable breathing phase for respiratory gating using velocity deformable registration in patients with lung cancer

    International Nuclear Information System (INIS)

    Aarons, Y.; Wightman, F.; Roxby, P.; Kron, T.

    2011-01-01

    Full text: Respiratory gated radiotherapy is a high-precision technique where the treatment beam is turned on during a predetermined phase of the breathing cycle in order to minimise dose to surrounding healthy dose sensitive structures. We aim to compare inspiration and expiration phases to determine which is more stable in the breathing cycle to perform respiratory gating. Methods Nine patients underwent a planning time resolved 4DCT (Philips Brilliance 16-multislice widebore) and repeat 4DCT during weeks I, 3 and 5 of a radical course of radiotherapy for lung cancer. Inspiration scans were co-registered to the same phase image of the original planning CT using rigid and then deformable registration with Velocity software. The process was repeated for scans at exhalation phase. The deformation matrix for the diaphragm was used to compare the reproducibility of breathing phases. In the majority of patients (seven of nine) the expiration phase was found to be the more stable compared with inspiration. The maximum diaphragm displacement exceeded 3 cm in one case for the registered inhalation images while the deformation was typically half of that in the exhalation images. Interestingly, several patients showed significant differences in deformation for the left and right diaphragm. Conclusions In a group of lung cancer patients we found the expiration phase to be more reproducible for delivering respiratory gated RT, when compared with inspiration.

  13. Respiratory-Gated MRgHIFU in Upper Abdomen Using an MR-Compatible In-Bore Digital Camera

    Directory of Open Access Journals (Sweden)

    Vincent Auboiroux

    2014-01-01

    Full Text Available Objective. To demonstrate the technical feasibility and the potential interest of using a digital optical camera inside the MR magnet bore for monitoring the breathing cycle and subsequently gating the PRFS MR thermometry, MR-ARFI measurement, and MRgHIFU sonication in the upper abdomen. Materials and Methods. A digital camera was reengineered to remove its magnetic parts and was further equipped with a 7 m long USB cable. The system was electromagnetically shielded and operated inside the bore of a closed 3T clinical scanner. Suitable triggers were generated based on real-time motion analysis of the images produced by the camera (resolution 640×480 pixels, 30 fps. Respiratory-gated MR-ARFI prepared MRgHIFU ablation was performed in the kidney and liver of two sheep in vivo, under general anaesthesia and ventilator-driven forced breathing. Results. The optical device demonstrated very good MR compatibility. The current setup permitted the acquisition of motion artefact-free and high resolution MR 2D ARFI and multiplanar interleaved PRFS thermometry (average SNR 30 in liver and 56 in kidney. Microscopic histology indicated precise focal lesions with sharply delineated margins following the respiratory-gated HIFU sonications. Conclusion. The proof-of-concept for respiratory motion management in MRgHIFU using an in-bore digital camera has been validated in vivo.

  14. Real-time prediction and gating of respiratory motion using an extended Kalman filter and Gaussian process regression

    International Nuclear Information System (INIS)

    Bukhari, W; Hong, S-M

    2015-01-01

    Motion-adaptive radiotherapy aims to deliver a conformal dose to the target tumour with minimal normal tissue exposure by compensating for tumour motion in real time. The prediction as well as the gating of respiratory motion have received much attention over the last two decades for reducing the targeting error of the treatment beam due to respiratory motion. In this article, we present a real-time algorithm for predicting and gating respiratory motion that utilizes a model-based and a model-free Bayesian framework by combining them in a cascade structure. The algorithm, named EKF-GPR + , implements a gating function without pre-specifying a particular region of the patient’s breathing cycle. The algorithm first employs an extended Kalman filter (LCM-EKF) to predict the respiratory motion and then uses a model-free Gaussian process regression (GPR) to correct the error of the LCM-EKF prediction. The GPR is a non-parametric Bayesian algorithm that yields predictive variance under Gaussian assumptions. The EKF-GPR + algorithm utilizes the predictive variance from the GPR component to capture the uncertainty in the LCM-EKF prediction error and systematically identify breathing points with a higher probability of large prediction error in advance. This identification allows us to pause the treatment beam over such instances. EKF-GPR + implements the gating function by using simple calculations based on the predictive variance with no additional detection mechanism. A sparse approximation of the GPR algorithm is employed to realize EKF-GPR + in real time. Extensive numerical experiments are performed based on a large database of 304 respiratory motion traces to evaluate EKF-GPR + . The experimental results show that the EKF-GPR + algorithm effectively reduces the prediction error in a root-mean-square (RMS) sense by employing the gating function, albeit at the cost of a reduced duty cycle. As an example, EKF-GPR + reduces the patient-wise RMS error to 37%, 39% and 42

  15. Real-time prediction and gating of respiratory motion using an extended Kalman filter and Gaussian process regression

    Science.gov (United States)

    Bukhari, W.; Hong, S.-M.

    2015-01-01

    Motion-adaptive radiotherapy aims to deliver a conformal dose to the target tumour with minimal normal tissue exposure by compensating for tumour motion in real time. The prediction as well as the gating of respiratory motion have received much attention over the last two decades for reducing the targeting error of the treatment beam due to respiratory motion. In this article, we present a real-time algorithm for predicting and gating respiratory motion that utilizes a model-based and a model-free Bayesian framework by combining them in a cascade structure. The algorithm, named EKF-GPR+, implements a gating function without pre-specifying a particular region of the patient’s breathing cycle. The algorithm first employs an extended Kalman filter (LCM-EKF) to predict the respiratory motion and then uses a model-free Gaussian process regression (GPR) to correct the error of the LCM-EKF prediction. The GPR is a non-parametric Bayesian algorithm that yields predictive variance under Gaussian assumptions. The EKF-GPR+ algorithm utilizes the predictive variance from the GPR component to capture the uncertainty in the LCM-EKF prediction error and systematically identify breathing points with a higher probability of large prediction error in advance. This identification allows us to pause the treatment beam over such instances. EKF-GPR+ implements the gating function by using simple calculations based on the predictive variance with no additional detection mechanism. A sparse approximation of the GPR algorithm is employed to realize EKF-GPR+ in real time. Extensive numerical experiments are performed based on a large database of 304 respiratory motion traces to evaluate EKF-GPR+. The experimental results show that the EKF-GPR+ algorithm effectively reduces the prediction error in a root-mean-square (RMS) sense by employing the gating function, albeit at the cost of a reduced duty cycle. As an example, EKF-GPR+ reduces the patient-wise RMS error to 37%, 39% and 42% in

  16. Real-time prediction and gating of respiratory motion using an extended Kalman filter and Gaussian process regression.

    Science.gov (United States)

    Bukhari, W; Hong, S-M

    2015-01-07

    Motion-adaptive radiotherapy aims to deliver a conformal dose to the target tumour with minimal normal tissue exposure by compensating for tumour motion in real time. The prediction as well as the gating of respiratory motion have received much attention over the last two decades for reducing the targeting error of the treatment beam due to respiratory motion. In this article, we present a real-time algorithm for predicting and gating respiratory motion that utilizes a model-based and a model-free Bayesian framework by combining them in a cascade structure. The algorithm, named EKF-GPR(+), implements a gating function without pre-specifying a particular region of the patient's breathing cycle. The algorithm first employs an extended Kalman filter (LCM-EKF) to predict the respiratory motion and then uses a model-free Gaussian process regression (GPR) to correct the error of the LCM-EKF prediction. The GPR is a non-parametric Bayesian algorithm that yields predictive variance under Gaussian assumptions. The EKF-GPR(+) algorithm utilizes the predictive variance from the GPR component to capture the uncertainty in the LCM-EKF prediction error and systematically identify breathing points with a higher probability of large prediction error in advance. This identification allows us to pause the treatment beam over such instances. EKF-GPR(+) implements the gating function by using simple calculations based on the predictive variance with no additional detection mechanism. A sparse approximation of the GPR algorithm is employed to realize EKF-GPR(+) in real time. Extensive numerical experiments are performed based on a large database of 304 respiratory motion traces to evaluate EKF-GPR(+). The experimental results show that the EKF-GPR(+) algorithm effectively reduces the prediction error in a root-mean-square (RMS) sense by employing the gating function, albeit at the cost of a reduced duty cycle. As an example, EKF-GPR(+) reduces the patient-wise RMS error to 37%, 39% and

  17. In vivo measurements of relaxation process in the human liver by MRI. The role of respiratory gating/triggering

    DEFF Research Database (Denmark)

    Thomsen, C; Henriksen, O; Ring, P

    1988-01-01

    In vivo estimation of relaxation processes in the liver by magnetic resonance imaging (MRI) may be helpful for characterization of various pathological conditions in the liver. However, such measurements may be significantly hampered by movement of the liver with the respiration. The effect...... of synchronization of data acquisition to the respiratory cycle on measured T1- and T2-relaxation curves was studied in normal subjects, patients with diffuse liver disease, and patients with focal liver pathology. Multi spin echo sequences with five different repetition times were used. The measurements were...... carried out with and without respiratory gating/triggering. In the healthy subjects as well as in the patients with diffuse liver diseases respiratory synchronization did not alter the obtained relaxation curves. However, in the patients with focal pathology the relaxation curves were significantly...

  18. Integrating respiratory-gated PET-based target volume delineation in liver SBRT planning, a pilot study

    International Nuclear Information System (INIS)

    Riou, Olivier; Thariat, Juliette; Serrano, Benjamin; Azria, David; Paulmier, Benoit; Villeneuve, Remy; Fenoglietto, Pascal; Artenie, Antonella; Ortholan, Cécile; Faraggi, Marc

    2014-01-01

    To assess the feasibility and benefit of integrating four-dimensional (4D) Positron Emission Tomography (PET) – computed tomography (CT) for liver stereotactic body radiation therapy (SBRT) planning. 8 patients with 14 metastases were accrued in the study. They all underwent a non-gated PET and a 4D PET centered on the liver. The same CT scan was used for attenuation correction, registration, and considered the planning CT for SBRT planning. Six PET phases were reconstructed for each 4D PET. By applying an individualized threshold to the 4D PET, a Biological Internal Target Volume (BITV) was generated for each lesion. A gated Planning Target Volume (PTVg) was created by adding 3 mm to account for set-up margins. This volume was compared to a manual Planning Target Volume (PTV) delineated with the help of a semi-automatic Biological Target Volume (BTV) obtained from the non-gated exam. A 5 mm radial and a 10 mm craniocaudal margins were applied to account for tumor motion and set-up margins to create the PTV. One undiagnosed liver metastasis was discovered thanks to the 4D PET. The semi-automatic BTV were significantly smaller than the BITV (p = 0.0031). However, after applying adapted margins, 4D PET allowed a statistically significant decrease in the PTVg as compared to the PTV (p = 0.0052). In comparison to non-gated PET, 4D PET may better define the respiratory movements of liver targets and improve SBRT planning for liver metastases. Furthermore, non respiratory-gated PET exams can both misdiagnose liver metastases and underestimate the real internal target volumes

  19. A radial sampling strategy for uniform k-space coverage with retrospective respiratory gating in 3D ultrashort-echo-time lung imaging.

    Science.gov (United States)

    Park, Jinil; Shin, Taehoon; Yoon, Soon Ho; Goo, Jin Mo; Park, Jang-Yeon

    2016-05-01

    The purpose of this work was to develop a 3D radial-sampling strategy which maintains uniform k-space sample density after retrospective respiratory gating, and demonstrate its feasibility in free-breathing ultrashort-echo-time lung MRI. A multi-shot, interleaved 3D radial sampling function was designed by segmenting a single-shot trajectory of projection views such that each interleaf samples k-space in an incoherent fashion. An optimal segmentation factor for the interleaved acquisition was derived based on an approximate model of respiratory patterns such that radial interleaves are evenly accepted during the retrospective gating. The optimality of the proposed sampling scheme was tested by numerical simulations and phantom experiments using human respiratory waveforms. Retrospectively, respiratory-gated, free-breathing lung MRI with the proposed sampling strategy was performed in healthy subjects. The simulation yielded the most uniform k-space sample density with the optimal segmentation factor, as evidenced by the smallest standard deviation of the number of neighboring samples as well as minimal side-lobe energy in the point spread function. The optimality of the proposed scheme was also confirmed by minimal image artifacts in phantom images. Human lung images showed that the proposed sampling scheme significantly reduced streak and ring artifacts compared with the conventional retrospective respiratory gating while suppressing motion-related blurring compared with full sampling without respiratory gating. In conclusion, the proposed 3D radial-sampling scheme can effectively suppress the image artifacts due to non-uniform k-space sample density in retrospectively respiratory-gated lung MRI by uniformly distributing gated radial views across the k-space. Copyright © 2016 John Wiley & Sons, Ltd.

  20. A novel respiratory motion compensation strategy combining gated beam delivery and mean target position concept - A compromise between small safety margins and long duty cycles

    International Nuclear Information System (INIS)

    Guckenberger, Matthias; Kavanagh, Anthony; Webb, Steve; Brada, Michael

    2011-01-01

    Purpose: To evaluate a novel respiratory motion compensation strategy combining gated beam delivery with the mean target position (MTP) concept for pulmonary stereotactic body radiotherapy (SBRT). Materials and methods: Four motion compensation strategies were compared for 10 targets with motion amplitudes between 6 mm and 31 mm: the internal target volume concept (plan ITV ); the MTP concept where safety margins were adapted based on 4D dose accumulation (plan MTP ); gated beam delivery without margins for motion compensation (plan gated ); a novel approach combining gating and the MTP concept (plan gated and MTP ). Results: For 5/10 targets with an average motion amplitude of 9 mm, the differences in the mean lung dose (MLD) between plan gated and plan MTP were gated and MTP . Despite significantly shorter duty cycles, plan gated reduced the MLD by gated and MTP . The MLD was increased by 18% in plan MTP compared to that of plan gated and MTP . Conclusions: For pulmonary targets with motion amplitudes >10-15 mm, the combination of gating and the MTP concept allowed small safety margins with simultaneous long duty cycles.

  1. Low-dose respiratory-gated PET/CT: based on 30 mA tube current

    International Nuclear Information System (INIS)

    Wu Ping; Li Sijin; Zhang Yanlan; Hao Xinzhong; Qin Zhixing; Yan Min; Cheng Pengliang; Wu Zhifang

    2013-01-01

    Objective: To establish a low-dose but image-comparable respiratory-gated PET/CT (RG PET/CT) protocol based on 30 mA tube current plus other improved scanning parameters, such as the tube current, the number of respiratory phase and length of breathing cycle. Methods: Twenty-six patients with 18 F-FDG-intaking lung nodules underwent one-bed standard-dose PET/CT (120 mA, 2 min/bed) and low dose RG PET/CT (30 mA, 6 respiratory phases, 1 min/phase). The radiation dose and image quality were analyzed subsequently with signal to noise ratio (SNR) for PET and the homogeneity, noise level for CT in the water phantom respectively. Otherwise the CT images were both visual evaluated by two experienced doctors. In addition, different respiratory cycle was simulated to observe its relation with radiation dose. Results: The effective dose of low-dose RG PET/CT was 4.88∼7.69 mSv [mean (5.68±0.83) mSv]. The PET SNR showed no significance between groups. The homogeneity of 30 mA is good (< 5 HU), although noise level was high, the visual character like lobulation, speculation of lung nodule was superior in some respiratory phases. The radiation dose was positively correlated with respiratory cycle. Conclusions: The performance of low-dose RG PET/CT was comparable to those of standard-dose PET/CT based on a protocol with 30 mA tube current, 6 respiratory phases and breathing state of eupnoea. It produced a much lower radiation exposure and the image quality was enough for clinical use such as delineation of tumor active target, characterization and staging of lung nodules, etc. (authors)

  2. Evaluating FDG uptake changes between pre and post therapy respiratory gated PET scans

    International Nuclear Information System (INIS)

    Aristophanous, Michalis; Yong, Yue; Yap, Jeffrey T.; Killoran, Joseph H.; Allen, Aaron M.; Berbeco, Ross I.; Chen, Aileen B.

    2012-01-01

    Purpose: Whole body (3D) and respiratory gated (4D) FDG-PET/CT scans performed pre-radiotherapy (pre-RT) and post-radiotherapy (post-RT) were analyzed to investigate the impact of 4D PET in evaluating 18F-fluorodeoxyglucose (FDG) uptake changes due to therapy, relative to traditional 3D PET. Methods and materials: 3D and 4D sequential FDG-PET/CT scans were acquired pre-RT and approximately one month post-RT for patients with non-small cell lung cancer (NSCLC). The lesions of high uptake targeted with radiotherapy were identified on the pre-RT scan of each patient. Each lesion on the 3D and each of the five phases of the 4D scan were analyzed using a region of interest (ROI). For each patient the ROIs of the pre-RT scans were used to locate the areas of initial FDG uptake on the post-RT scans following rigid registration. Post-RT ROIs were drawn and the FDG uptake was compared with that of the pre-RT scans. Results: Sixteen distinct lesions from 12 patients were identified and analyzed. Standardized uptake value (SUV) maxima were significantly higher (p-value <0.005) for the lesions as measured on the 4D compared to 3D PET. Comparison of serial pre and post-RT scans showed a mean 62% decrease in SUV with the 3D PET scan (range 36–89%), and a 67% decrease with the 4D PET scan (range 30–89%). The mean absolute difference in SUV change on 3D versus 4D scans was 4.9%, with a range 0–15% (p-value = 0.07). Conclusions: Signal recovery with 4D PET results in higher SUVs when compared to standard 3D PET. Consequently, differences in the evaluation of SUV changes between pre and post-RT plans were observed. Such difference can have a significant impact in PET-based response assessment.

  3. Feasibility of Systematic Respiratory-Gated Acquisition in Unselected Patients Referred for 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    Directory of Open Access Journals (Sweden)

    Philippe Robin

    2018-02-01

    Full Text Available ObjectiveRespiratory motion in 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT induces blurred images, leading to errors in location and quantification for lung and abdominal lesions. Various methods have been developed to correct for these artifacts, and most of current PET/CT scanners are equipped with a respiratory gating system. However, they are not routinely performed because their use is time-consuming. The aim of this study is to assess the feasibility and quantitative impact of a systematic respiratory-gated acquisition in unselected patients referred for FDG PET/CT, without increasing acquisition time.MethodsPatients referred for a FDG PET/CT examination to the nuclear medicine department of Brest University Hospital were consecutively enrolled, during a 3-month period. Cases presenting lung or liver uptakes were analyzed. Two sets of images were reconstructed from data recorded during a unique acquisition with a continuous table speed of 1 mm/s of the used Biograph mCT Flow PET/CT scanner: standard free-breathing images, and respiratory-gated images. Lesion location and quantitative parameters were recorded and compared.ResultsFrom October 1 2015 to December 31 2015, 847 patients were referred for FDG PET/CT, 741 underwent a respiratory-gated acquisition. Out of them, 213 (29% had one or more lung or liver uptake but 82 (38% had no usable respiratory-gated signal. Accordingly, 131 (62% patients with 183 lung or liver uptakes were analyzed. Considering the 183 lesions, 140 and 43 were located in the lungs and the liver, respectively. The median (IQR difference between respiratory-gated images and non-gated images was 18% (4−32 for SUVmax, increasing to 30% (14−57 in lower lobes for lung lesions, and −18% (−40 to −4 for MTV (p < 0.05. Technologists’ active personal dosimetry and mean total examinations duration were not statistically different between periods with and without

  4. Assessment of regional lung functional impairment with co-registered respiratory-gated ventilation/perfusion SPET-CT images: initial experiences

    International Nuclear Information System (INIS)

    Suga, Kazuyoshi; Yasuhiko, Kawakami; Zaki, Mohammed; Yamashita, Tomio; Seto, Aska; Matsumoto, Tsuneo; Matsunaga, Naofumi

    2004-01-01

    In this study, respiratory-gated ventilation and perfusion single-photon emission tomography (SPET) were used to define regional functional impairment and to obtain reliable co-registration with computed tomography (CT) images in various lung diseases. Using a triple-headed SPET unit and a physiological synchroniser, gated perfusion SPET was performed in a total of 78 patients with different pulmonary diseases, including metastatic nodules (n=15); in 34 of these patients, it was performed in combination with gated technetium-99m Technegas SPET. Projection data were acquired using 60 stops over 120 for each detector. Gated end-inspiration and ungated images were reconstructed from 1/8 data centered at peak inspiration for each regular respiratory cycle and full respiratory cycle data, respectively. Gated images were registered with tidal inspiration CT images using automated three-dimensional (3D) registration software. Registration mismatch was assessed by measuring 3D distance of the centroid of the nine selected round perfusion-defective nodules. Gated SPET images were completed within 29 min, and increased the number of visible ventilation and perfusion defects by 9.7% and 17.2%, respectively, as compared with ungated images; furthermore, lesion-to-normal lung contrast was significantly higher on gated SPET images. In the nine round perfusion-defective nodules, gated images yielded a significantly better SPET-CT match compared with ungated images (4.9±3.1 mm vs 19.0±9.1 mm, P<0.001). The co-registered SPET-CT images allowed accurate perception of the location and extent of each ventilation/perfusion defect on the underlying CT anatomy, and characterised the pathophysiology of the various diseases. By reducing respiratory motion effects and enhancing perfusion/ventilation defect clarity, gated SPET can provide reliable co-registered images with CT images to accurately characterise regional functional impairment in various lung diseases. (orig.)

  5. An automatic respiratory gating method for the improvement of microcirculation evaluation: application to contrast-enhanced ultrasound studies of focal liver lesions

    Energy Technology Data Exchange (ETDEWEB)

    Mule, S; Kachenoura, N; Lucidarme, O; De Oliveira, A; Pellot-Barakat, C; Herment, A; Frouin, F, E-mail: Sebastien.Mule@gmail.com [INSERM UMR-S 678, 75634 Paris Cedex 13 (France)

    2011-08-21

    Contrast-enhanced ultrasound (CEUS), with the recent development of both contrast-specific imaging modalities and microbubble-based contrast agents, allows noninvasive quantification of microcirculation in vivo. Nevertheless, functional parameters obtained by modeling contrast uptake kinetics could be impaired by respiratory motion. Accordingly, we developed an automatic respiratory gating method and tested it on 35 CEUS hepatic datasets with focal lesions. Each dataset included fundamental mode and cadence contrast pulse sequencing (CPS) mode sequences acquired simultaneously. The developed method consisted in (1) the estimation of the respiratory kinetics as a linear combination of the first components provided by a principal components analysis constrained by a prior knowledge on the respiratory rate in the frequency domain, (2) the automated generation of two respiratory-gated subsequences from the CPS mode sequence by detecting end-of-inspiration and end-of-expiration phases from the respiratory kinetics. The fundamental mode enabled a more reliable estimation of the respiratory kinetics than the CPS mode. The k-means algorithm was applied on both the original CPS mode sequences and the respiratory-gated subsequences resulting in clustering maps and associated mean kinetics. Our respiratory gating process allowed better superimposition of manually drawn lesion contours on k-means clustering maps as well as substantial improvement of the quality of contrast uptake kinetics. While the quality of maps and kinetics was satisfactory in only 11/35 datasets before gating, it was satisfactory in 34/35 datasets after gating. Moreover, noise amplitude estimated within the delineated lesions was reduced from 62 {+-} 21 to 40 {+-} 10 (p < 0.01) after gating. These findings were supported by the low residual horizontal (0.44 {+-} 0.29 mm) and vertical (0.15 {+-} 0.16 mm) shifts found during manual motion correction of each respiratory-gated subsequence. The developed

  6. Evaluation of MotionSim XY/4D for patient specific QA of respiratory gated treatment for lung cancer

    International Nuclear Information System (INIS)

    Wen, C.; Ackerly, T.; Lancaster, C.; Bailey, N.

    2011-01-01

    Full text: A commercial system-MotionSim XY/4D(TM) capable of simulating two-dimensional tumour motion and measuring planar dose with diode-matrix was evaluated at the Alfred Hospital, for establishing patient-specific QA programme of respiratory gated treatment of lung cancer. This study presents the investigation of accuracies, limitations and the practical aspects of that system. Planar doses generated on iPlan-TM by mapping clinical beams to a scanned-in water phantom were measured by MotionSim XY/4D-TM with 5 cm water equivalent build-up at normal incidence. The gated delivery using ExacTrac-TM through tracking infrared markers simulating external respiration surrogate was measured simultaneously with Gaf-ChromicR RTQA2 film and MapCHECK 2TM . Dose maps of both non-gated and gated beams with 30% duty cycle were compared with both film and diodes measurements. Differences in dose distribution were analysed with built-in tools in MapCHECK2 TM and the effect of residual motion within the beamenabled window was then assessed. Preliminary results indicate that difference between Gafchromic film and MapCHECK2 measurements of same beam was ignorable. Gated dose delivery to a target at 9 mm maximum motion was in good agreement with planned dose. Complement to measurements suggested in AAPM Report No.9 I I, this QA device can detect any random error and assess the magnitude of residual target motion through analysing differences between planned and delivered doses as gamma function. Although some user-friendliness aspects could be improved, it meets its specification and can be used for routine clinical QA purposes provided calibrations were performed and procedures were followed.

  7. Respiratory-gated segment reconstruction for radiation treatment planning using 256-slice CT-scanner during free breathing

    Science.gov (United States)

    Mori, Shinichiro; Endo, Masahiro; Kohno, Ryosuke; Minohara, Shinichi; Kohno, Kazutoshi; Asakura, Hiroshi; Fujiwara, Hideaki; Murase, Kenya

    2005-04-01

    The conventional respiratory-gated CT scan technique includes anatomic motion induced artifacts due to the low temporal resolution. They are a significant source of error in radiotherapy treatment planning for the thorax and upper abdomen. Temporal resolution and image quality are important factors to minimize planning target volume margin due to the respiratory motion. To achieve high temporal resolution and high signal-to-noise ratio, we developed a respiratory gated segment reconstruction algorithm and adapted it to Feldkamp-Davis-Kress algorithm (FDK) with a 256-detector row CT. The 256-detector row CT could scan approximately 100 mm in the cranio-caudal direction with 0.5 mm slice thickness in one rotation. Data acquisition for the RS-FDK relies on the assistance of the respiratory sensing system by a cine scan mode (table remains stationary). We evaluated RS-FDK in phantom study with the 256-detector row CT and compared it with full scan (FS-FDK) and HS-FDK results with regard to volume accuracy and image noise, and finally adapted the RS-FDK to an animal study. The RS-FDK gave a more accurate volume than the others and it had the same signal-to-noise ratio as the FS-FDK. In the animal study, the RS-FDK visualized the clearest edges of the liver and pulmonary vessels of all the algorithms. In conclusion, the RS-FDK algorithm has a capability of high temporal resolution and high signal-to-noise ratio. Therefore it will be useful when combined with new radiotherapy techniques including image guided radiation therapy (IGRT) and 4D radiation therapy.

  8. MO-FG-CAMPUS-JeP2-02: Audiovisual Biofeedback Guided Respiratory-Gated MRI: An Investigation of Tumor Definition and Scan Time for Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D; Pollock, S; Keall, P [University of Sydney, Sydney, NSW (Australia); Greer, P; Lapuz, C; Ludbrook, J [Calvary Mater Newcastle, Newcastle, NSW (Australia); Kim, T [Virginia Commonwealth University, Glen Allen, VA (United States)

    2016-06-15

    Purpose: Breathing consistency variations can cause respiratory-related motion blurring and artifacts and increase in MRI scan time due to inadequate respiratory-gating and discarding of breathing cycles. In a previous study the concept of audiovisual biofeedback (AV) guided respiratory-gated MRI was tested with healthy volunteers and it demonstrated image quality improvement on anatomical structures and scan time reduction. This study tests the applicability of AV-guided respiratorygated MRI for lung cancer in a prospective patient study. Methods: Image quality and scan time were investigated in thirteen lung cancer patients who underwent two 3T MRI sessions. In the first MRI session (pre-treatment), respiratory-gated MR images with free breathing (FB) and AV were acquired at inhalation and exhalation. An RF navigator placed on the liver dome was employed for the respiratory-gated MRI. This was repeated in the second MRI session (mid-treatment). Lung tumors were delineated on each dataset. FB and AV were compared in terms of (1) tumor definition assessed by lung tumor contours and (2) intra-patient scan time variation using the total image acquisition time of inhalation and exhalation datasets from the first and second MRI sessions across 13 lung cancer patients. Results: Compared to FB AV-guided respiratory-gated MRI improved image quality for contouring tumors with sharper boundaries and less blurring resulted in the improvement of tumor definition. Compared to FB the variation of intra-patient scan time with AV was reduced by 48% (p<0.001) from 54 s to 28 s. Conclusion: This study demonstrated that AV-guided respiratorygated MRI improved the quality of tumor images and fixed tumor definition for lung cancer. These results suggest that audiovisual biofeedback breathing guidance has the potential to control breathing for adequate respiratory-gating for lung cancer imaging and radiotherapy.

  9. MO-FG-CAMPUS-JeP2-02: Audiovisual Biofeedback Guided Respiratory-Gated MRI: An Investigation of Tumor Definition and Scan Time for Lung Cancer

    International Nuclear Information System (INIS)

    Lee, D; Pollock, S; Keall, P; Greer, P; Lapuz, C; Ludbrook, J; Kim, T

    2016-01-01

    Purpose: Breathing consistency variations can cause respiratory-related motion blurring and artifacts and increase in MRI scan time due to inadequate respiratory-gating and discarding of breathing cycles. In a previous study the concept of audiovisual biofeedback (AV) guided respiratory-gated MRI was tested with healthy volunteers and it demonstrated image quality improvement on anatomical structures and scan time reduction. This study tests the applicability of AV-guided respiratorygated MRI for lung cancer in a prospective patient study. Methods: Image quality and scan time were investigated in thirteen lung cancer patients who underwent two 3T MRI sessions. In the first MRI session (pre-treatment), respiratory-gated MR images with free breathing (FB) and AV were acquired at inhalation and exhalation. An RF navigator placed on the liver dome was employed for the respiratory-gated MRI. This was repeated in the second MRI session (mid-treatment). Lung tumors were delineated on each dataset. FB and AV were compared in terms of (1) tumor definition assessed by lung tumor contours and (2) intra-patient scan time variation using the total image acquisition time of inhalation and exhalation datasets from the first and second MRI sessions across 13 lung cancer patients. Results: Compared to FB AV-guided respiratory-gated MRI improved image quality for contouring tumors with sharper boundaries and less blurring resulted in the improvement of tumor definition. Compared to FB the variation of intra-patient scan time with AV was reduced by 48% (p<0.001) from 54 s to 28 s. Conclusion: This study demonstrated that AV-guided respiratorygated MRI improved the quality of tumor images and fixed tumor definition for lung cancer. These results suggest that audiovisual biofeedback breathing guidance has the potential to control breathing for adequate respiratory-gating for lung cancer imaging and radiotherapy.

  10. The effects of tumor motion on planning and delivery of respiratory-gated IMRT

    International Nuclear Information System (INIS)

    Hugo, Geoffrey D.; Agazaryan, Nzhde; Solberg, Timothy D.

    2003-01-01

    The purpose of this study is to investigate the effects of object motion on the planning and delivery of IMRT. Two phantoms containing objects were imaged using CT under a variety of motion conditions. The effects of object motion on axial CT acquisition with and without gating were assessed qualitatively and quantitatively. Measurements of effective slice width and position for the CT scans were made. Mutual information image fusion was adapted for use as a quantitative measure of object deformation in CT images. IMRT plans were generated on the CT scans of the moving and gated object images. These plans were delivered with motion, with and without gating, and the delivery error between the moving deliveries and a nonmoving delivery was assessed using a scalable vector-based index. Motion during CT acquisition produces motion artifact, object deformation, and object mispositioning, which can be substantially reduced with gating. Objects that vary in cross section in the direction of motion exhibit the most deformation in CT images. Mutual information provides a useful quantitative estimate of object deformation. The delivery of IMRT in the presence of target motion significantly alters the delivered dose distribution in relation to the planned distribution. The utilization of gating for IMRT treatment, including imaging, planning, and delivery, significantly reduces the errors introduced by object motion

  11. Detection and compensation of organ/lesion motion using 4D-PET/CT respiratory gated acquisition techniques

    International Nuclear Information System (INIS)

    Bettinardi, Valentino; Picchio, Maria; Di Muzio, Nadia; Gianolli, Luigi; Gilardi, Maria Carla; Messa, Cristina

    2010-01-01

    Purpose: To describe the degradation effects produced by respiratory organ and lesion motion on PET/CT images and to define the role of respiratory gated (RG) 4D-PET/CT techniques to compensate for such effects. Methods: Based on the literature and on our own experience, technical recommendations and clinical indications for the use of RG 4D PET/CT have been outlined. Results: RG 4D-PET/CT techniques require a state of the art PET/CT scanner, a respiratory monitoring system and dedicated acquisition and processing protocols. Patient training is particularly important to obtain a regular breathing pattern. An adequate number of phases has to be selected to balance motion compensation and statistical noise. RG 4D PET/CT motion free images may be clinically useful for tumour tissue characterization, monitoring patient treatment and target definition in radiation therapy planning. Conclusions: RG 4D PET/CT is a valuable tool to improve image quality and quantitative accuracy and to assess and measure organ and lesion motion for radiotherapy planning.

  12. SU-E-J-211: Design and Study of In-House Software Based Respiratory Motion Monitoring, Controlling and Breath-Hold Device for Gated Radiotherapy

    International Nuclear Information System (INIS)

    Shanmugam, Senthilkumar

    2014-01-01

    Purpose: The purpose of this present work was to fabricate an in-house software based respiratory monitoring, controlling and breath-hold device using computer software programme which guides the patient to have uniform breath hold in response to request during the gated radiotherapy. Methods: The respiratory controlling device consists of a computer, inhouse software, video goggles, a highly sensitive sensor for measurement of distance, mounting systems, a camera, a respiratory signal device, a speaker and a visual indicator. The computer is used to display the respiratory movements of the patient with digital as well as analogue respiration indicators during the respiration cycle, to control, breath-hold and analyze the respiratory movement using indigenously developed software. Results: Studies were conducted with anthropomophic phantoms by simulating the respiratory motion on phantoms and recording the respective movements using the respiratory monitoring device. The results show good agreement between the simulated and measured movements. Further studies were conducted for 60 cancer patients with several types of cancers in the thoracic region. The respiratory movement cycles for each fraction of radiotherapy treatment were recorded and compared. Alarm indications are provided in the system to indicate when the patient breathing movement exceeds the threshold level. This will help the patient to maintain uniform breath hold during the radiotherapy treatment. Our preliminary clinical test results indicate that our device is highly reliable and able to maintain the uniform respiratory motion and breathe hold during the entire course of gated radiotherapy treatment. Conclusion: An indigenous respiratory monitoring device to guide the patient to have uniform breath hold device was fabricated. The alarm feature and the visual waveform indicator in the system guide the patient to have normal respiration. The signal from the device can be connected to the radiation

  13. SU-E-J-211: Design and Study of In-House Software Based Respiratory Motion Monitoring, Controlling and Breath-Hold Device for Gated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, Senthilkumar [Madurai Medical College ' Govt. Rajaji Hospital, Madurai (India)

    2014-06-01

    Purpose: The purpose of this present work was to fabricate an in-house software based respiratory monitoring, controlling and breath-hold device using computer software programme which guides the patient to have uniform breath hold in response to request during the gated radiotherapy. Methods: The respiratory controlling device consists of a computer, inhouse software, video goggles, a highly sensitive sensor for measurement of distance, mounting systems, a camera, a respiratory signal device, a speaker and a visual indicator. The computer is used to display the respiratory movements of the patient with digital as well as analogue respiration indicators during the respiration cycle, to control, breath-hold and analyze the respiratory movement using indigenously developed software. Results: Studies were conducted with anthropomophic phantoms by simulating the respiratory motion on phantoms and recording the respective movements using the respiratory monitoring device. The results show good agreement between the simulated and measured movements. Further studies were conducted for 60 cancer patients with several types of cancers in the thoracic region. The respiratory movement cycles for each fraction of radiotherapy treatment were recorded and compared. Alarm indications are provided in the system to indicate when the patient breathing movement exceeds the threshold level. This will help the patient to maintain uniform breath hold during the radiotherapy treatment. Our preliminary clinical test results indicate that our device is highly reliable and able to maintain the uniform respiratory motion and breathe hold during the entire course of gated radiotherapy treatment. Conclusion: An indigenous respiratory monitoring device to guide the patient to have uniform breath hold device was fabricated. The alarm feature and the visual waveform indicator in the system guide the patient to have normal respiration. The signal from the device can be connected to the radiation

  14. Quality assurance device for four-dimensional IMRT or SBRT and respiratory gating using patient-specific intrafraction motion kernels.

    Science.gov (United States)

    Nelms, Benjamin E; Ehler, Eric; Bragg, Henry; Tomé, Wolfgang A

    2007-09-17

    Emerging technologies such as four-dimensional computed tomography (4D CT) and implanted beacons are expected to allow clinicians to accurately model intrafraction motion and to quantitatively estimate internal target volumes (ITVs) for radiation therapy involving moving targets. In the case of intensity-modulated (IMRT) and stereotactic body radiation therapy (SBRT) delivery, clinicians must consider the interplay between the temporal nature of the modulation and the target motion within the ITV. A need exists for a 4D IMRT/SBRT quality assurance (QA) device that can incorporate and analyze customized intrafraction motion as it relates to dose delivery and respiratory gating. We built a 4D IMRT/SBRT prototype device and entered (X, Y, Z)(T) coordinates representing a motion kernel into a software application that 1. transformed the kernel into beam-specific two-dimensional (2D) motion "projections," 2. previewed the motion in real time, and 3. drove a recision X-Y motorized device that had, atop it, a mounted planar IMRT QA measurement device. The detectors that intersected the target in the beam's-eye-view of any single phase of the breathing cycle (a small subset of all the detectors) were defined as "target detectors" to be analyzed for dose uniformity between multiple fractions. Data regarding the use of this device to quantify dose variation fraction-to-fraction resulting from target motion (for several delivery modalities and with and without gating) have been recently published. A combined software and hardware solution for patient-customized 4D IMRT/SBRT QA is an effective tool for assessing IMRT delivery under conditions of intrafraction motion. The 4D IMRT QA device accurately reproduced the projected motion kernels for all beam's-eye-view motion kernels. This device has been proved to, effectively quantify the degradation in dose uniformity resulting from a moving target within a static planning target volume, and, integrate with a commercial

  15. Quality assurance device for four‐dimensional IMRT or SBRT and respiratory gating using patient‐specific intrafraction motion kernels

    Science.gov (United States)

    Ehler, Eric; Bragg, Henry; Tomé, Wolfgang A.

    2007-01-01

    Emerging technologies such as four‐dimensional computed tomography (4D CT) and implanted beacons are expected to allow clinicians to accurately model intrafraction motion and to quantitatively estimate internal target volumes (ITVs) for radiation therapy involving moving targets. In the case of intensity‐modulated (IMRT) and stereotactic body radiation therapy (SBRT) delivery, clinicians must consider the interplay between the temporal nature of the modulation and the target motion within the ITV. A need exists for a 4D IMRT/SBRT quality assurance (QA) device that can incorporate and analyze customized intrafraction motion as it relates to dose delivery and respiratory gating. We built a 4D IMRT/SBRT prototype device and entered (X, Y, Z)(T) coordinates representing a motion kernel into a software application that transformed the kernel into beam‐specific two‐dimensional (2D) motion “projections,”previewed the motion in real time, anddrove a precision X–Y motorized device that had, atop it, a mounted planar IMRT QA measurement device. The detectors that intersected the target in the beam's‐eye‐view of any single phase of the breathing cycle (a small subset of all the detectors) were defined as “target detectors” to be analyzed for dose uniformity between multiple fractions. Data regarding the use of this device to quantify dose variation fraction‐to‐fraction resulting from target motion (for several delivery modalities and with and without gating) have been recently published. A combined software and hardware solution for patient‐customized 4D IMRT/ SBRT QA is an effective tool for assessing IMRT delivery under conditions of intrafraction motion. The 4D IMRT QA device accurately reproduced the projected motion kernels for all beam's‐eye‐view motion kernels. This device has been proved to • effectively quantify the degradation in dose uniformity resulting from a moving target within a static planning target volume, and • integrate

  16. Measurement of time delays in gated radiotherapy for realistic respiratory motions

    International Nuclear Information System (INIS)

    Chugh, Brige P.; Quirk, Sarah; Conroy, Leigh; Smith, Wendy L.

    2014-01-01

    Purpose: Gated radiotherapy is used to reduce internal motion margins, escalate target dose, and limit normal tissue dose; however, its temporal accuracy is limited. Beam-on and beam-off time delays can lead to treatment inefficiencies and/or geographic misses; therefore, AAPM Task Group 142 recommends verifying the temporal accuracy of gating systems. Many groups use sinusoidal phantom motion for this, under the tacit assumption that use of sinusoidal motion for determining time delays produces negligible error. The authors test this assumption by measuring gating time delays for several realistic motion shapes with increasing degrees of irregularity. Methods: Time delays were measured on a linear accelerator with a real-time position management system (Varian TrueBeam with RPM system version 1.7.5) for seven motion shapes: regular sinusoidal; regular realistic-shape; large (40%) and small (10%) variations in amplitude; large (40%) variations in period; small (10%) variations in both amplitude and period; and baseline drift (30%). Film streaks of radiation exposure were generated for each motion shape using a programmable motion phantom. Beam-on and beam-off time delays were determined from the difference between the expected and observed streak length. Results: For the system investigated, all sine, regular realistic-shape, and slightly irregular amplitude variation motions had beam-off and beam-on time delays within the AAPM recommended limit of less than 100 ms. In phase-based gating, even small variations in period resulted in some time delays greater than 100 ms. Considerable time delays over 1 s were observed with highly irregular motion. Conclusions: Sinusoidal motion shapes can be considered a reasonable approximation to the more complex and slightly irregular shapes of realistic motion. When using phase-based gating with predictive filters even small variations in period can result in time delays over 100 ms. Clinical use of these systems for patients

  17. Measurement of time delays in gated radiotherapy for realistic respiratory motions

    Energy Technology Data Exchange (ETDEWEB)

    Chugh, Brige P.; Quirk, Sarah; Conroy, Leigh; Smith, Wendy L., E-mail: Wendy.Smith@albertahealthservices.ca [Department of Medical Physics, Tom Baker Cancer Centre, Calgary, Alberta T2N 4N2 (Canada)

    2014-09-15

    Purpose: Gated radiotherapy is used to reduce internal motion margins, escalate target dose, and limit normal tissue dose; however, its temporal accuracy is limited. Beam-on and beam-off time delays can lead to treatment inefficiencies and/or geographic misses; therefore, AAPM Task Group 142 recommends verifying the temporal accuracy of gating systems. Many groups use sinusoidal phantom motion for this, under the tacit assumption that use of sinusoidal motion for determining time delays produces negligible error. The authors test this assumption by measuring gating time delays for several realistic motion shapes with increasing degrees of irregularity. Methods: Time delays were measured on a linear accelerator with a real-time position management system (Varian TrueBeam with RPM system version 1.7.5) for seven motion shapes: regular sinusoidal; regular realistic-shape; large (40%) and small (10%) variations in amplitude; large (40%) variations in period; small (10%) variations in both amplitude and period; and baseline drift (30%). Film streaks of radiation exposure were generated for each motion shape using a programmable motion phantom. Beam-on and beam-off time delays were determined from the difference between the expected and observed streak length. Results: For the system investigated, all sine, regular realistic-shape, and slightly irregular amplitude variation motions had beam-off and beam-on time delays within the AAPM recommended limit of less than 100 ms. In phase-based gating, even small variations in period resulted in some time delays greater than 100 ms. Considerable time delays over 1 s were observed with highly irregular motion. Conclusions: Sinusoidal motion shapes can be considered a reasonable approximation to the more complex and slightly irregular shapes of realistic motion. When using phase-based gating with predictive filters even small variations in period can result in time delays over 100 ms. Clinical use of these systems for patients

  18. Reductions in the variations of respiration signals for respiratory-gated radiotherapy when using the video-coaching respiration guiding system

    Science.gov (United States)

    Lee, Hyun Jeong; Yea, Ji Woon; Oh, Se An

    2015-07-01

    Respiratory-gated radiation therapy (RGRT) has been used to minimize the dose to normal tissue in lung-cancer radiotherapy. The present research aims to improve the regularity of respiration in RGRT by using a video-coached respiration guiding system. In the study, 16 patients with lung cancer were evaluated. The respiration signals of the patients were measured by using a realtime position management (RPM) respiratory gating system (Varian, USA), and the patients were trained using the video-coaching respiration guiding system. The patients performed free breathing and guided breathing, and the respiratory cycles were acquired for ~5 min. Then, Microsoft Excel 2010 software was used to calculate the mean and the standard deviation for each phase. The standard deviation was computed in order to analyze the improvement in the respiratory regularity with respect to the period and the displacement. The standard deviation of the guided breathing decreased to 48.8% in the inhale peak and 24.2% in the exhale peak compared with the values for the free breathing of patient 6. The standard deviation of the respiratory cycle was found to be decreased when using the respiratory guiding system. The respiratory regularity was significantly improved when using the video-coaching respiration guiding system. Therefore, the system is useful for improving the accuracy and the efficiency of RGRT.

  19. 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 improve hemodynamic assessment. This has been a challenge because compensation of respiratory motion is difficult to achieve, but it is paramount to limit artifacts and improve accuracy. In this work we propose a self-gating technique for respiratory motion-compensation integrated into a whole-heart 4D...... flow acquisition that overcomes these challenges. Flow components are measured in all three directions for each pixel over the complete cardiac cycle, and 1D volume projections are obtained at certain time intervals for respiratory gating in real time during the acquisition. The technique was tested...

  20. Deep-inspiration breath-hold PET/CT versus free breathing PET/CT and respiratory gating PET for reference. Evaluation in 95 patients with lung cancer

    International Nuclear Information System (INIS)

    Kawano, Tsuyoshi; Ohtake, Eiji; Inoue, Tomio

    2011-01-01

    The objective of this study was to define the factors that correlate with differences in maximum standardized uptake value (SUV max ) in deep-inspiration breath-hold (DIBH) and free breathing (FB) positron emission tomography (PET)/CT admixed with respiratory gating (RG) PET for reference. Patients (n=95) with pulmonary lesions were evaluated at one facility over 33 months. After undergoing whole-body PET/CT, a RG PET and FB PET/CT scans were obtained, followed by a DIBH PET/CT scan. All scans were recorded using a list-mode dynamic collection method with respiratory gating. The RG PET was reconstructed using phase gating without attenuation correction; the FB PET was reconstructed from the RG PET sinogram datasets with attenuation correction. Respiratory motion distance, breathing cycle speed, and waveform of RG PET were recorded. The SUV max of FB PET/CT and DIBH PET/CT were recorded: the percent difference in SUV max between the FB and DIBH scans was defined as the %BH-index. The %BH-index was significantly higher for lesions in the lower lung area than in the upper lung area. Respiratory motion distance was significantly higher in the lower lung area than in the upper lung area. A significant relationship was observed between the %BH-index and respiratory motion distance. Waveforms without steady end-expiration tended to show a high %BH-index. Significant inverse relationships were observed between %BH-index and cycle speed, and between respiratory motion distance and cycle speed. Decrease in SUV max of FB PET/CT was due to tumor size, distribution of lower lung, long respiratory movement at slow breathing cycle speeds, and respiratory waveforms without steady end-expiration. (author)

  1. Effectiveness of respiratory-gated radiotherapy with audio-visual biofeedback for synchrotron-based scanned heavy-ion beam delivery

    Science.gov (United States)

    He, Pengbo; Li, Qiang; Zhao, Ting; Liu, Xinguo; Dai, Zhongying; Ma, Yuanyuan

    2016-12-01

    A synchrotron-based heavy-ion accelerator operates in pulse mode at a low repetition rate that is comparable to a patient’s breathing rate. To overcome inefficiencies and interplay effects between the residual motion of the target and the scanned heavy-ion beam delivery process for conventional free breathing (FB)-based gating therapy, a novel respiratory guidance method was developed to help patients synchronize their breathing patterns with the synchrotron excitation patterns by performing short breath holds with the aid of personalized audio-visual biofeedback (BFB) system. The purpose of this study was to evaluate the treatment precision, efficiency and reproducibility of the respiratory guidance method in scanned heavy-ion beam delivery mode. Using 96 breathing traces from eight healthy volunteers who were asked to breathe freely and guided to perform short breath holds with the aid of BFB, a series of dedicated four-dimensional dose calculations (4DDC) were performed on a geometric model which was developed assuming a linear relationship between external surrogate and internal tumor motions. The outcome of the 4DDCs was quantified in terms of the treatment time, dose-volume histograms (DVH) and dose homogeneity index. Our results show that with the respiratory guidance method the treatment efficiency increased by a factor of 2.23-3.94 compared with FB gating, depending on the duty cycle settings. The magnitude of dose inhomogeneity for the respiratory guidance methods was 7.5 times less than that of the non-gated irradiation, and good reproducibility of breathing guidance among different fractions was achieved. Thus, our study indicates that the respiratory guidance method not only improved the overall treatment efficiency of respiratory-gated scanned heavy-ion beam delivery, but also had the advantages of lower dose uncertainty and better reproducibility among fractions.

  2. SU-G-JeP1-08: Dual Modality Verification for Respiratory Gating Using New Real- Time Tumor Tracking Radiotherapy System

    Energy Technology Data Exchange (ETDEWEB)

    Shiinoki, T; Hanazawa, H; Shibuya, K [Yamaguchi University, Ube, Yamaguchi (Japan); Kawamura, S; Koike, M; Yuasa, Y; Uehara, T; Fujimoto, K [Yamaguchi University Hospital, Ube, Yamaguchi (Japan)

    2016-06-15

    Purpose: The respirato ry gating system combined the TrueBeam and a new real-time tumor-tracking radiotherapy system (RTRT) was installed. The RTRT system consists of two x-ray tubes and color image intensifiers. Using fluoroscopic images, the fiducial marker which was implanted near the tumor was tracked and was used as the internal surrogate for respiratory gating. The purposes of this study was to develop the verification technique of the respiratory gating with the new RTRT using cine electronic portal image device images (EPIDs) of TrueBeam and log files of the RTRT. Methods: A patient who underwent respiratory gated SBRT of the lung using the RTRT were enrolled in this study. For a patient, the log files of three-dimensional coordinate of fiducial marker used as an internal surrogate were acquired using the RTRT. Simultaneously, the cine EPIDs were acquired during respiratory gated radiotherapy. The data acquisition was performed for one field at five sessions during the course of SBRT. The residual motion errors were calculated using the log files (E{sub log}). The fiducial marker used as an internal surrogate into the cine EPIDs was automatically extracted by in-house software based on the template-matching algorithm. The differences between the the marker positions of cine EPIDs and digitally reconstructed radiograph were calculated (E{sub EPID}). Results: Marker detection on EPID using in-house software was influenced by low image contrast. For one field during the course of SBRT, the respiratory gating using the RTRT showed the mean ± S.D. of 95{sup th} percentile E{sub EPID} were 1.3 ± 0.3 mm,1.1 ± 0.5 mm,and those of E{sub log} were 1.5 ± 0.2 mm, 1.1 ± 0.2 mm in LR and SI directions, respectively. Conclusion: We have developed the verification method of respiratory gating combined TrueBeam and new real-time tumor-tracking radiotherapy system using EPIDs and log files.

  3. Field Programmable Gate Array (FPGA Respiratory Monitoring System Using a Flow Microsensor and an Accelerometer

    Directory of Open Access Journals (Sweden)

    Mellal Idir

    2017-04-01

    Full Text Available This paper describes a non-invasive system for respiratory monitoring using a Micro Electro Mechanical Systems (MEMS flow sensor and an IMU (Inertial Measurement Unit accelerometer. The designed system is intended to be wearable and used in a hospital or at home to assist people with respiratory disorders. To ensure the accuracy of our system, we proposed a calibration method based on ANN (Artificial Neural Network to compensate the temperature drift of the silicon flow sensor. The sigmoid activation functions used in the ANN model were computed with the CORDIC (COordinate Rotation DIgital Computer algorithm. This algorithm was also used to estimate the tilt angle in body position. The design was implemented on reconfigurable platform FPGA.

  4. Respiratory

    Science.gov (United States)

    The words "respiratory" and "respiration" refer to the lungs and breathing. ... Boron WF. Organization of the respiratory system. In: Boron WF, Boulpaep EL, eds. Medical Physiology . 3rd ed. Philadelphia, PA: Elsevier; 2017:chap 26.

  5. Verification of respiratory-gated radiotherapy with new real-time tumour-tracking radiotherapy system using cine EPID images and a log file

    Science.gov (United States)

    Shiinoki, Takehiro; Hanazawa, Hideki; Yuasa, Yuki; Fujimoto, Koya; Uehara, Takuya; Shibuya, Keiko

    2017-02-01

    A combined system comprising the TrueBeam linear accelerator and a new real-time tumour-tracking radiotherapy system, SyncTraX, was installed at our institution. The objectives of this study are to develop a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine electronic portal image device (EPID) images and a log file and to verify this treatment in clinical cases. Respiratory-gated radiotherapy was performed using TrueBeam and the SyncTraX system. Cine EPID images and a log file were acquired for a phantom and three patients during the course of the treatment. Digitally reconstructed radiographs (DRRs) were created for each treatment beam using a planning CT set. The cine EPID images, log file, and DRRs were analysed using a developed software. For the phantom case, the accuracy of the proposed method was evaluated to verify the respiratory-gated radiotherapy. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker used as an internal surrogate were calculated to evaluate the gating accuracy and set-up uncertainty in the superior-inferior (SI), anterior-posterior (AP), and left-right (LR) directions. The proposed method achieved high accuracy for the phantom verification. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker were  ⩽3 mm and  ±3 mm in the SI, AP, and LR directions. We proposed a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine EPID images and a log file and showed that this treatment is performed with high accuracy in clinical cases. This work was partly presented at the 58th Annual meeting of American Association of Physicists in Medicine.

  6. Verification of respiratory-gated radiotherapy with new real-time tumour-tracking radiotherapy system using cine EPID images and a log file.

    Science.gov (United States)

    Shiinoki, Takehiro; Hanazawa, Hideki; Yuasa, Yuki; Fujimoto, Koya; Uehara, Takuya; Shibuya, Keiko

    2017-02-21

    A combined system comprising the TrueBeam linear accelerator and a new real-time tumour-tracking radiotherapy system, SyncTraX, was installed at our institution. The objectives of this study are to develop a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine electronic portal image device (EPID) images and a log file and to verify this treatment in clinical cases. Respiratory-gated radiotherapy was performed using TrueBeam and the SyncTraX system. Cine EPID images and a log file were acquired for a phantom and three patients during the course of the treatment. Digitally reconstructed radiographs (DRRs) were created for each treatment beam using a planning CT set. The cine EPID images, log file, and DRRs were analysed using a developed software. For the phantom case, the accuracy of the proposed method was evaluated to verify the respiratory-gated radiotherapy. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker used as an internal surrogate were calculated to evaluate the gating accuracy and set-up uncertainty in the superior-inferior (SI), anterior-posterior (AP), and left-right (LR) directions. The proposed method achieved high accuracy for the phantom verification. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker were  ⩽3 mm and  ±3 mm in the SI, AP, and LR directions. We proposed a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine EPID images and a log file and showed that this treatment is performed with high accuracy in clinical cases.

  7. Development of patient-controlled respiratory gating system based on visual guidance for magnetic-resonance image-guided radiation therapy.

    Science.gov (United States)

    Kim, Jung-In; Lee, Hanyoung; Wu, Hong-Gyun; Chie, Eui Kyu; Kang, Hyun-Cheol; Park, Jong Min

    2017-09-01

    The aim of this study is to develop a visual guidance patient-controlled (VG-PC) respiratory gating system for respiratory-gated magnetic-resonance image-guided radiation therapy (MR-IGRT) and to evaluate the performance of the developed system. The near-real-time cine planar MR image of a patient acquired during treatment was transmitted to a beam projector in the treatment room through an optical fiber cable. The beam projector projected the cine MR images inside the bore of the ViewRay system in order to be visible to a patient during treatment. With this visual information, patients voluntarily controlled their respiration to put the target volume into the gating boundary (gating window). The effect of the presence of the beam projector in the treatment room on the image quality of the MRI was investigated by evaluating the signal-to-noise ratio (SNR), uniformity, low-contrast detectability, high-contrast spatial resolution, and spatial integrity with the VG-PC gating system. To evaluate the performance of the developed system, we applied the VG-PC gating system to a total of seven patients; six patients received stereotactic ablative radiotherapy (SABR) and one patient received conventional fractionated radiation therapy. The projected cine MR images were visible even when the room light was on. No image data loss or additional time delay during delivery of image data were observed. Every indicator representing MRI quality, including SNR, uniformity, low-contrast detectability, high-contrast spatial resolution, and spatial integrity exhibited values higher than the tolerance levels of the manufacturer with the VG-PC gating system; therefore, the presence of the VG-PC gating system in the treatment room did not degrade the MR image quality. The average beam-off times due to respiratory gating with and without the VG-PC gating system were 830.3 ± 278.2 s and 1264.2 ± 302.1 s respectively (P = 0.005). Consequently, the total treatment times excluding

  8. Management of the baseline shift using a new and simple method for respiratory-gated radiation therapy: Detectability and effectiveness of a flexible monitoring system

    International Nuclear Information System (INIS)

    Tachibana, Hidenobu; Kitamura, Nozomi; Ito, Yasushi; Kawai, Daisuke; Nakajima, Masaru; Tsuda, Akihisa; Shiizuka, Hisao

    2011-01-01

    Purpose: In respiratory-gated radiation therapy, a baseline shift decreases the accuracy of target coverage and organs at risk (OAR) sparing. The effectiveness of audio-feedback and audio-visual feedback in correcting the baseline shift in the breathing pattern of the patient has been demonstrated previously. However, the baseline shift derived from the intrafraction motion of the patient's body cannot be corrected by these methods. In the present study, the authors designed and developed a simple and flexible system. Methods: The system consisted of a web camera and a computer running our in-house software. The in-house software was adapted to template matching and also to no preimage processing. The system was capable of monitoring the baseline shift in the intrafraction motion of the patient's body. Another marker box was used to monitor the baseline shift due to the flexible setups required of a marker box for gated signals. The system accuracy was evaluated by employing a respiratory motion phantom and was found to be within AAPM Task Group 142 tolerance (positional accuracy <2 mm and temporal accuracy <100 ms) for respiratory-gated radiation therapy. Additionally, the effectiveness of this flexible and independent system in gated treatment was investigated in healthy volunteers, in terms of the results from the differences in the baseline shift detectable between the marker positions, which the authors evaluated statistically. Results: The movement of the marker on the sternum [1.599 ± 0.622 mm (1 SD)] was substantially decreased as compared with the abdomen [6.547 ± 0.962 mm (1 SD)]. Additionally, in all of the volunteers, the baseline shifts for the sternum [-0.136 ± 0.868 (2 SD)] were in better agreement with the nominal baseline shifts than was the case for the abdomen [-0.722 ± 1.56 mm (2 SD)]. The baseline shifts could be accurately measured and detected using the monitoring system, which could acquire the movement of the marker on the sternum. The

  9. High tech hypofractionation to optimise treatment

    DEFF Research Database (Denmark)

    Johansen, Jørgen

    2015-01-01

    Hypofractionation has lately been implemented as standard treatment in the adjuvant setting as well as in radical radiotherapy for various solid tumors such as in breast and lung carcinomas. Also for metastatic disease in the liver or brain, hypofractionated stereotactic radiotherapy has proven e...

  10. Interfractional changes in tumour volume and position during entire radiotherapy courses for lung cancer with respiratory gating and image guidance

    Energy Technology Data Exchange (ETDEWEB)

    Juhler-Noettrup, Trine; Korreman, Stine S.; Pedersen, Anders N.; Persson, Gitte F.; Aarup, Lasse R.; Nystroem, Haakan; Olsen, Mikael; Tarnavski, Nikolai; Specht, Lena (Dept. of Radiation Oncology, The Finsen Centre, Copenhagen (Denmark))

    2008-08-15

    Introduction. With the purpose of implementing gated radiotherapy for lung cancer patients, this study investigated the interfraction variations in tumour size and internal displacement over entire treatment courses. To explore the potential of image guided radiotherapy (IGRT) the variations were measured using a set-up strategy based on imaging of bony landmarks and compared to a strategy using in room lasers, skin tattoos and cupper landmarks. Materials and methods. During their six week treatment course of 60Gy in 2Gy fractions, ten patients underwent 3 respiratory gated CT scans. The tumours were contoured on each CT scan to evaluate the variations in volumes and position. The lung tumours and the mediastinal tumours were contoured separately. The positional variations were measured as 3D mobility vectors and correlated to matching of the scans using the two different strategies. Results. The tumour size was significantly reduced from the first to the last CT scan. For the lung tumours the reduction was 19%, p=0.03, and for the mediastinal tumours the reduction was 34%, p=0.0007. The mean 3D mobility vector and the SD for the lung tumours was 0.51cm (+-0.21) for matching using bony landmarks and 0.85cm (+-0.54) for matching using skin tattoos. For the mediastinal tumours the corresponding vectors and SD's were 0.55cm (+-0.19) and 0.72cm (+-0.43). The differences between the vectors were significant for the lung tumours p=0.004. The interfractional overlap of lung tumours was 80-87% when matched using bony landmarks and 70-76% when matched using skin tattoos. The overlap of the mediastinal tumours were 60-65% and 41-47%, respectively. Conclusions. Despite the use of gating the tumours varied considerably, regarding both position and volume. The variations in position were dependent on the set-up strategy. Set-up using IGRT was superior to set-up using skin tattoos.

  11. Interfractional changes in tumour volume and position during entire radiotherapy courses for lung cancer with respiratory gating and image guidance

    International Nuclear Information System (INIS)

    Juhler-Noettrup, Trine; Korreman, Stine S.; Pedersen, Anders N.; Persson, Gi tte F.; Aarup, Lasse R.; Nystroem, Haakan; Olsen, Mikael; Tarnavski, Nikolai; Sp echt, Lena

    2008-01-01

    Introduction. With the purpose of implementing gated radiotherapy for lung cancer patients, this study investigated the interfraction variations in tumour size and internal displacement over entire treatment courses. To explore the potential of image guided radiotherapy (IGRT) the variations were measured using a set-up strategy based on imaging of bony landmarks and compared to a strategy using in room lasers, skin tattoos and cupper landmarks. Materials and methods. During their six week treatment course of 60Gy in 2Gy fractions, ten patients underwent 3 respiratory gated CT scans. The tumours were contoured on each CT scan to evaluate the variations in volumes and position. The lung tumours and the mediastinal tumours were contoured separately. The positional variations were measured as 3D mobility vectors and correlated to matching of the scans using the two different strategies. Results. The tumour size was significantly reduced from the first to the last CT scan. For the lung tumours the reduction was 19%, p=0.03, and for the mediastinal tumours the reduction was 34%, p=0.0007. The mean 3D mobility vector and the SD for the lung tumours was 0.51cm (±0.21) for matching using bony landmarks and 0.85cm (±0.54) for matching using skin tattoos. For the mediastinal tumours the corresponding vectors and SD's were 0.55cm (±0.19) and 0.72cm (±0.43). The differences between the vectors were significant for the lung tumours p=0.004. The interfractional overlap of lung tumours was 80-87% when matched using bony landmarks and 70-76% when matched using skin tattoos. The overlap of the mediastinal tumours were 60-65% and 41-47%, respectively. Conclusions. Despite the use of gating the tumours varied considerably, regarding both position and volume. The variations in position were dependent on the set-up strategy. Set-up using IGRT was superior to set-up using skin tattoos

  12. Does mean heart dose sufficiently reflect coronary artery exposure in left-sided breast cancer radiotherapy. Influence of respiratory gating

    Energy Technology Data Exchange (ETDEWEB)

    Becker-Schiebe, Martina [Klinikum Braunschweig, Department of Radiotherapy and Radio-Oncology, Braunschweig (Germany); Hannover Medical School, Radiation Oncology, Hannover (Germany); Stockhammer, Maxi; Franz, Heiko [Klinikum Braunschweig, Department of Gynecology and Obstetrics, Braunschweig (Germany); Hoffmann, Wolfgang; Wetzel, Fabian [Klinikum Braunschweig, Department of Radiotherapy and Radio-Oncology, Braunschweig (Germany)

    2016-09-15

    With extensive use of systemic treatment, the issue of cardiac mortality after breast cancer radiation (RT) is still important. The aim of our analysis was to clarify whether the dose to one surrogate parameter (e. g., mean heart dose, as used in most studies) reflects the dose to the other cardiovascular structures especially the left anterior descending artery depending on breathing-adapted RT. A total of 130 patients who underwent adjuvant RT (50.4 Gy plus boost 9-16 Gy) were evaluated. In all, 71 patients were treated with free-breathing and 59 patients using respiratory monitoring (gated RT). Dosimetric associations were calculated. The mean dose to the heart (Dmean heart) was reduced from 2.7 (0.8-5.2) Gy to 2.4 (1.1-4.6) Gy, the Dmean LAD (left anterior descending artery) decreased from 11.1 (1.3-28.6) Gy to 9.3 (2.2-19.9) Gy with gated RT (p = 0.04). A significant relationship was shown for Dmean{sub heart}-Dmean LAD, V25heart-Dmean LAD and Dmax heart-Dmax LAD for gated patients only (p < 0.01). For every 1 Gy increase in Dmean heart, mean LAD doses rose by 3.6 Gy, without gating V25 ≤5 % did not assure a benefit and resulted in Dmean LAD between 1.3 and 28.6 Gy. A significant reduction and association of heart and coronary artery (LAD) doses using inspiratory gating was shown. However, in free-breathing plans commonly measured dose constraints do not allow precise estimation of the dose to the coronary arteries. (orig.) [German] Das Risiko kardialer Spaetfolgen nach Bestrahlung (RT) eines Mammakarzinoms spielt insbesondere auch aufgrund der zunehmenden systemischen Begleittherapien eine wichtige Rolle. Unklar ist, welche koronaren und/oder myokardialen Mechanismen hier entscheidend sind. Der Einfluss der Atemtriggerung und der daraus resultierenden geometrischen Lagevariabilitaet der Risikoorgane auf die Dosisverteilung am Herzen/Koronarien sollte geprueft werden, um zu klaeren, inwieweit die mittlere Herzdosis ein ausreichender Surrogatparameter fuer

  13. Initial clinical results for breath-hold CT-based processing of respiratory-gated PET acquisitions

    International Nuclear Information System (INIS)

    Fin, Loic; Daouk, Joel; Morvan, Julie; Esper, Isabelle El; Saidi, Lazhar; Meyer, Marc-Etienne; Bailly, Pascal

    2008-01-01

    Respiratory motion causes uptake in positron emission tomography (PET) images of chest structures to spread out and misregister with the CT images. This misregistration can alter the attenuation correction and thus the quantisation of PET images. In this paper, we present the first clinical results for a respiratory-gated PET (RG-PET) processing method based on a single breath-hold CT (BH-CT) acquisition, which seeks to improve diagnostic accuracy via better PET-to-CT co-registration. We refer to this method as ''CT-based'' RG-PET processing. Thirteen lesions were studied. Patients underwent a standard clinical PET protocol and then the CT-based protocol, which consists of a 10-min List Mode RG-PET acquisition, followed by a shallow end-expiration BH-CT. The respective performances of the CT-based and clinical PET methods were evaluated by comparing the distances between the lesions' centroids on PET and CT images. SUV MAX and volume variations were also investigated. The CT-based method showed significantly lower (p=0.027) centroid distances (mean change relative to the clinical method =-49%; range =-100% to 0%). This led to higher SUV MAX (mean change =+33%; range =-4% to 69%). Lesion volumes were significantly lower (p=0.022) in CT-based PET volumes (mean change =-39%: range =-74% to -1%) compared with clinical ones. A CT-based RG-PET processing method can be implemented in clinical practice with a small increase in radiation exposure. It improves PET-CT co-registration of lung lesions and should lead to more accurate attenuation correction and thus SUV measurement. (orig.)

  14. Respiratory-Gated Proton Beam Therapy for Hepatocellular Carcinoma Adjacent to the Gastrointestinal Tract without Fiducial Markers

    Directory of Open Access Journals (Sweden)

    Miu Mizuhata

    2018-02-01

    Full Text Available The efficacy of proton beam therapy (PBT for hepatocellular carcinoma (HCC has been reported, but insertion of fiducial markers in the liver is usually required. We evaluated the efficacy and toxicity of respiratory-gated PBT without fiducial markers for HCC located within 2 cm of the gastrointestinal tract. From March 2011 to December 2015 at our institution, 40 patients were evaluated (median age, 72 years; range, 38–87 years. All patients underwent PBT at a dose of 60 to 80 cobalt gray equivalents (CGE in 20 to 38 fractions. The median follow-up period was 19.9 months (range, 1.2–72.3 months. The median tumor size was 36.5 mm (range, 11–124 mm. Kaplan–Meier estimates of the 2-year overall survival, progression-free survival, and local tumor control rates were 76%, 60%, and 94%, respectively. One patient (2.5% developed a grade 3 gastric ulcer and one (2.5% developed grade 3 ascites retention; none of the remaining patients developed grade >3 toxicities (National Cancer Institute Common Terminology Criteria for Adverse Events ver. 4.0.. This study indicates that PBT without fiducial markers achieves good local control without severe treatment-related toxicity of the gastrointestinal tract for HCC located within 2 cm of the gastrointestinal tract.

  15. Three-Dimensional Respiratory-Gated Coronary Mr Angiography with Reference to X-Ray Coronary Angiography

    International Nuclear Information System (INIS)

    Ikonen, A. E. J.; Manninen, H. I.; Vainio, P.; Vanninen, R. L.; Matsi, P. J.; Soimakallio, S.; Hirvonen, T.P.J.; Hartikainen, J.E.K.

    2003-01-01

    Purpose: To assess the clinical value of three-dimensional coronary MR angiography (CMRA) in the detection of significant coronary artery stenosis using conventional X-ray angiography as the standard reference. Material and Methods: Sixty-nine patients underwent X-ray coronary angiography and CMRA because of suspected or previously diagnosed coronary artery disease. MRI was performed with a 1.5-T whole body imaging system using ECG-triggered 3D gradient echo sequence with retrospective navigator echo respiratory gating and fat suppression. Results: A total of 276 coronary artery segments were analyzed. The X-ray coronary angiography was normal in 22 patients. Significant proximal stenoses (exceeding 50%) or occlusions were present in 102 coronary artery segments. In all, 120 stenoses or occlusions were identified in CMRA. Sixteen percent of the coronary artery segments had to be excluded because of poor image quality. The overall sensitivity and specificity for MRA for identification of significant stenosis were 75% and 62%, respectively. CMRA correctly detected 89% of patients with at least one vessel disease, but 6 patients with coronary artery disease would have been missed. Conclusions: Because of the high data exclusion and false-negative case rate, CMRA with retrospective navigator echo triggering is at present not suitable as a clinical screening method in coronary artery disease

  16. Carbon-ion scanning lung treatment planning with respiratory-gated phase-controlled rescanning: simulation study using 4-dimensional CT data.

    Science.gov (United States)

    Takahashi, Wataru; Mori, Shinichiro; Nakajima, Mio; Yamamoto, Naoyoshi; Inaniwa, Taku; Furukawa, Takuji; Shirai, Toshiyuki; Noda, Koji; Nakagawa, Keiichi; Kamada, Tadashi

    2014-11-11

    To moving lung tumors, we applied a respiratory-gated strategy to carbon-ion pencil beam scanning with multiple phase-controlled rescanning (PCR). In this simulation study, we quantitatively evaluated dose distributions based on 4-dimensional CT (4DCT) treatment planning. Volumetric 4DCTs were acquired for 14 patients with lung tumors. Gross tumor volume, clinical target volume (CTV) and organs at risk (OARs) were delineated. Field-specific target volumes (FTVs) were calculated, and 48Gy(RBE) in a single fraction was prescribed to the FTVs delivered from four beam angles. The dose assessment metrics were quantified by changing the number of PCR and the results for the ungated and gated scenarios were then compared. For the ungated strategy, the mean dose delivered to 95% of the volume of the CTV (CTV-D95) was in average 45.3 ± 0.9 Gy(RBE) even with a single rescanning (1 × PCR). Using 4 × PCR or more achieved adequate target coverage (CTV-D95 = 46.6 ± 0.3 Gy(RBE) for ungated 4 × PCR) and excellent dose homogeneity (homogeneity index =1.0 ± 0.2% for ungated 4 × PCR). Applying respiratory gating, percentage of lung receiving at least 20 Gy(RBE) (lung-V20) and heart maximal dose, averaged over all patients, significantly decreased by 12% (p lung tumors without gating. The use of a respiratory-gated strategy in combination with PCR reduced excessive doses to OARs.

  17. Clinical validation of free breathing respiratory triggered retrospectively cardiac gated cine balanced steady-state free precession cardiovascular magnetic resonance in sedated children

    OpenAIRE

    Krishnamurthy, Rajesh; Pednekar, Amol; Atweh, Lamya A; Vogelius, Esben; Chu, Zili David; Zhang, Wei; Maskatia, Shiraz; Masand, Prakash; Morris, Shaine A; Krishnamurthy, Ramkumar; Muthupillai, Raja

    2015-01-01

    Background Cine balanced steady-state free precession (SSFP), the preferred sequence for ventricular function, demands uninterrupted radio frequency (RF) excitation to maintain the steady-state during suspended respiration. This is difficult to accomplish in sedated children. In this work, we validate a respiratory triggered (RT) SSFP sequence that drives the magnetization to steady-state before commencing retrospectively cardiac gated cine acquisition in a sedated pediatric population. Metho...

  18. MR-guided percutaneous biopsy of solitary pulmonary lesions using a 1.0-T open high-field MRI scanner with respiratory gating

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ming; Huang, Jie; Xu, Yujun; He, Xiangmeng; Lue, Yubo; Liu, Qiang; Li, Chengli [Department of Interventional MRI, Shandong Medical Imaging Research Institute affiliated to Shandong University, Shandong Key Laboratory of Advanced Medical Imaging Technologies and Applications, Jinan, Shandong (China); Li, Lei [Qingdao Central Hospital, Department of Interventional Radiology, Qingdao, Shandong (China); Blanco Sequeiros, Roberto [Turku University Hospital, The South Western Finland Imaging Centre, Turku (Finland)

    2017-04-15

    To prospectively evaluate the feasibility, safety and accuracy of MR-guided percutaneous biopsy of solitary pulmonary lesions using a 1.0-T open MR scanner with respiratory gating. Sixty-five patients with 65 solitary pulmonary lesions underwent MR-guided percutaneous coaxial cutting needle biopsy using a 1.0-T open MR scanner with respiratory gating. Lesions were divided into two groups according to maximum lesion diameters: ≤2.0 cm (n = 31) and >2.0 cm (n = 34). The final diagnosis was established in surgery and subsequent histology. Diagnostic accuracy, sensitivity and specificity were compared between the groups using Fisher's exact test. Accuracy, sensitivity and specificity of MRI-guided percutaneous pulmonary biopsy in diagnosing malignancy were 96.9 %, 96.4 % and 100 %, respectively. Accuracy, sensitivity and specificity were 96.8 %, 96.3 % and 100 % for lesions 2.0 cm or smaller and 97.1 %, 96.4 % and 100 %, respectively, for lesions larger than 2.0 cm. There was no significant difference between the two groups (P > 0.05). Biopsy-induced complications encountered were pneumothorax in 12.3 % (8/65) and haemoptysis in 4.6 % (3/65). There were no serious complications. MRI-guided percutaneous biopsy using a 1.0-T open MR scanner with respiratory gating is an accurate and safe diagnostic technique in evaluation of pulmonary lesions. (orig.)

  19. SU-E-T-247: Determinations of the Optimal Phase for Respiratory Gated Radiotherapy From Statistical Analysis Using a Visible Guidance System

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S; Yea, J; Kang, M; Lee, H; Kim, S [Yeungnam University Medical Center, Daegu, Daegu (Korea, Republic of)

    2015-06-15

    Purpose: Respiratory gated radiation therapy (RGRT) is used to minimize the radiation dose to normal tissue in lung cancer patients. Determination of the optimal point in the respiratory phase of a patient is important in RGRT but it is not easy. The goal of the present study was to see if a visible guidance system is helpful in determining the optimal phase in respiratory gated therapy. Methods: The breathing signals of 23 lung cancer patients were recorded with a Real-time Position Management (RPM) respiratory gating system (Varian, USA). The patients underwent breathing training with our visible guidance system, after which their breathing signals were recorded during 5 min of free breathing and 5 min of guided breathing. The breathing signals recorded between 3 and 5 min before and after training were compared. We performed statistical analysis of the breathing signals to find the optimal duty cycle in guided breathing for RGRT. Results: The breathing signals aided by the visible guidance system had more regular cycles over time and smaller variations in the positions of the marker block than the free breathing signals. Of the 23 lung cancer patients, 19 showed statistically significant differences by time when the values obtained before and after breathing were compared (p < 0.05); 30% and 40% of the duty cycle, respectively, was determined to be the most effective, and the corresponding phases were 30 60% (duty cycle, 30%; p < 0.05) and 30 70% (duty cycle, 40%; p < 0.05). Conclusion: Respiratory regularity was significantly improved with the use of the RPM with our visible guiding system; therefore, it would help improve the accuracy and efficiency of RGRT.

  20. Hypofractionated radiotherapy for Graves' orbitopathy

    International Nuclear Information System (INIS)

    Heyd, R.; Herkstroeter, M.; Martin, T.; Zamboglou, N.; Strassmann, G.

    2001-01-01

    Background: Radiotherapy (RT) has been proven effective in the management of Graves' orbitopathy in numerous studies. Most commonly is the use of conventional fractionated RT and the value of hypofractionated irradiation has not been investigated. Materials and methods: The results in 33 euthyroid cases who underwent RT with a total dose of 21.0 Gy given in three weekly fractions of 3.0 Gy are retrospectively analyzed. The duration of symptoms ranged from 1-84 months and all of the cases had treatment failure after previous administration of corticosteroids. After a mean follow-up period of 33.6 months the overall results were assessed according to the criteria by Donaldson et al. and for evaluation of the clinical outcome a classification with the main criteria being eye-lid changes, exophthalmos, myopathy and eye nerve involvement was used. Results: At follow-up, the overall response to RT was 84.8% (28/33 cases). The analysis with the clinical classification demonstrated that in 19/33 (57.6%) cases occurred a decrease of eye lid changes and exophthalmos and 12/33 (36.4%) had a relief of myopathy. 2/33 cases (6.0%) developed an eye nerve compression causing the necessity of surgical decompression. 3/33 cases (9.0%) had a progression of at least of one of the single criteria of the score and therefore they were classified as non-responders. Conclusions: Hypofractionated RT has been proven effective for treatment of severe cases of Graves' orbitopathy in cases with a prolongated duration of symptoms. The comparison with literature data demonstrate that the results after hypofractionated RT are comparable to those obtained after conventional fractionated RT. (orig.)

  1. SU-E-T-66: Characterization of Radiation Dose Associated with Dark Currents During Beam Hold for Respiratory-Gated Electron Therapy

    International Nuclear Information System (INIS)

    Hessler, J; Gupta, N; Rong, Y; Weldon, M

    2014-01-01

    Purpose: The main objective of this study was to estimate the radiation dose contributed by dark currents associated with the respiratory-gated electron therapy during beam hold. The secondary aim was to determine clinical benefits of using respiratory-gated electron therapy for left-sided breast cancer patients with positive internal mammary nodes (IMN). Methods: Measurements of the dark current-induced dose in all electron modes were performed on multiple Siemens and Varian linear accelerators by manually simulating beam-hold during respiratory gating. Dose was quantified at the machine isocenter by comparing the collected charge to the known output for all energies ranging from 6 to 18 MeV for a 10cm × 10cm field at 100 SSD with appropriate solid-water buildup. Using the Eclipse treatment planning system, we compared the additional dose associated with dark current using gated electron fields to the dose uncertainties associated with matching gated photon fields and ungated electron fields. Dose uncertainties were seen as hot and cold spots along the match line of the fields. Results: The magnitude of the dose associated with dark current is highly correlated to the energy of the beam and the amount of time the beam is on hold. For lower energies (6–12 MeV), there was minimal dark current dose (0.1–1.3 cGy/min). Higher energies (15–18 MeV) showed measurable amount of doses. The dark current associated with the electron beam-hold varied between linear accelerator vendors and depended on dark current suppression and the age of the linear accelerator. Conclusion: For energies up to 12 MeV, the dose associated with the dark current for respiratorygated electron therapy was shown to be negligible, and therefore should be considered an option for treating IMN positive left-sided breast cancer patients. However, at higher energies the benefit of respiratory gating may be outweighed by dose due to the dark current

  2. Evaluation of accuracy about 2D vs 3D real-time position management system based on couch rotation when non-coplanar respiratory gated radiation therapy

    International Nuclear Information System (INIS)

    Kwon, Kyung Tae; Kim, Jung Soo; Sim, Hyun Sun; Min, Jung Whan; Son, Soon Yong; Han, Dong Kyoon

    2016-01-01

    Because of non-coplanar therapy with couch rotation in respiratory gated radiation therapy, the recognition of marker movement due to the change in the distance between the infrared camera and the marker due to the rotation of the couch is called RPM (Real-time The purpose of this paper is to evaluate the accuracy of motion reflections (baseline changes) of 2D gating configuration (two dot marker block) and 3D gating configuration (six dot marker block). The motion was measured by varying the couch angle in the clockwise and counterclockwise directions by 10° in the 2D gating configuration. In the 3D gating configuration, the couch angle was changed by 10° in the clockwise direction and compared with the baseline at the reference 0°. The reference amplitude was 1.173 to 1.165, the couch angle at 20° was 1.132, and the couch angle at 1.0° was 1.083. At 350° counterclockwise, the reference amplitude was 1.168 to 1.157, the couch angle at 340° was 1.124, and the couch angle at 330° was 1.079. In this study, the phantom is used to quantitatively evaluate the value of the amplitude according to couch change

  3. Evaluation of accuracy about 2D vs 3D real-time position management system based on couch rotation when non-coplanar respiratory gated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Kyung Tae; Kim, Jung Soo [Dongnam Health University, Suwon (Korea, Republic of); Sim, Hyun Sun [College of Health Sciences, Korea University, Seoul (Korea, Republic of); Min, Jung Whan [Shingu University College, Sungnam (Korea, Republic of); Son, Soon Yong [Wonkwang Health Science University, Iksan (Korea, Republic of); Han, Dong Kyoon [College of Health Sciences, EulJi University, Daejeon (Korea, Republic of)

    2016-12-15

    Because of non-coplanar therapy with couch rotation in respiratory gated radiation therapy, the recognition of marker movement due to the change in the distance between the infrared camera and the marker due to the rotation of the couch is called RPM (Real-time The purpose of this paper is to evaluate the accuracy of motion reflections (baseline changes) of 2D gating configuration (two dot marker block) and 3D gating configuration (six dot marker block). The motion was measured by varying the couch angle in the clockwise and counterclockwise directions by 10° in the 2D gating configuration. In the 3D gating configuration, the couch angle was changed by 10° in the clockwise direction and compared with the baseline at the reference 0°. The reference amplitude was 1.173 to 1.165, the couch angle at 20° was 1.132, and the couch angle at 1.0° was 1.083. At 350° counterclockwise, the reference amplitude was 1.168 to 1.157, the couch angle at 340° was 1.124, and the couch angle at 330° was 1.079. In this study, the phantom is used to quantitatively evaluate the value of the amplitude according to couch change.

  4. Respiratory-Gated Helical Computed Tomography of Lung: Reproducibility of Small Volumes in an Ex Vivo Model

    International Nuclear Information System (INIS)

    Biederer, Juergen; Dinkel, Julien; Bolte, Hendrik; Welzel, Thomas; Hoffmann, Beata M.Sc.; Thierfelder, Carsten; Mende, Ulrich; Debus, Juergen; Heller, Martin; Kauczor, Hans-Ulrich

    2007-01-01

    Purpose: Motion-adapted radiotherapy with gated irradiation or tracking of tumor positions requires dedicated imaging techniques such as four-dimensional (4D) helical computed tomography (CT) for patient selection and treatment planning. The objective was to evaluate the reproducibility of spatial information for small objects on respiratory-gated 4D helical CT using computer-assisted volumetry of lung nodules in a ventilated ex vivo system. Methods and Materials: Five porcine lungs were inflated inside a chest phantom and prepared with 55 artificial nodules (mean diameter, 8.4 mm ± 1.8). The lungs were respirated by a flexible diaphragm and scanned with 40-row detector CT (collimation, 24 x 1.2 mm; pitch, 0.1; rotation time, 1 s; slice thickness, 1.5 mm; increment, 0.8 mm). The 4D-CT scans acquired during respiration (eight per minute) and reconstructed at 0-100% inspiration and equivalent static scans were scored for motion-related artifacts (0 or absent to 3 or relevant). The reproducibility of nodule volumetry (three readers) was assessed using the variation coefficient (VC). Results: The mean volumes from the static and dynamic inspiratory scans were equal (364.9 and 360.8 mm 3 , respectively, p = 0.24). The static and dynamic end-expiratory volumes were slightly greater (371.9 and 369.7 mm 3 , respectively, p = 0.019). The VC for volumetry (static) was 3.1%, with no significant difference between 20 apical and 20 caudal nodules (2.6% and 3.5%, p = 0.25). In dynamic scans, the VC was greater (3.9%, p = 0.004; apical and caudal, 2.6% and 4.9%; p = 0.004), with a significant difference between static and dynamic in the 20 caudal nodules (3.5% and 4.9%, p = 0.015). This was consistent with greater motion-related artifacts and image noise at the diaphragm (p <0.05). The VC for interobserver variability was 0.6%. Conclusion: Residual motion-related artifacts had only minimal influence on volumetry of small solid lesions. This indicates a high reproducibility of

  5. Hypofractionated stereotactic irradiation. Basic and clinical researches

    International Nuclear Information System (INIS)

    Shibamoto, Yuta; Miyakawa, Akifumi; Iwata, Hiromitsu; Otsuka, Shinya; Ogino, Hiroyuki; Ayakawa, Shiho

    2011-01-01

    Hypofractionated stereotactic radiotherapy (SRT) has a number of biological advantages over single-session radiosurgery. An apparent trend is seen in the clinic towards shift from the latter to the former; however, there is no adequate model to convert single doses to hypofractionated doses. The linear-quadratic model overestimates the effect of single-fraction radiation. This should be kept in mind in evaluating the doses of stereotactic irradiation. ''Biological effective dose'' should not be used in radiosurgery and hypofractionated SRT. Clinically, we have used 3- to 10-fraction SRT for acoustic neuroma and benign skull base tumors using cyberknife and tomotherapy. Preliminary results are encouraging. (author)

  6. 18F-FDG PET-CT respiratory gating in characterization of pulmonary lesions. Approximation towards clinical indications

    International Nuclear Information System (INIS)

    Garcia Vicente, A.M.; Soriano Castrejon, A.M.; Talavera Rubio, M.P.; Leon Martin, A.A.; Palomar Munoz, A.M.; Pilkington Woll, J.P.; Poblete Garcia, V.M.

    2010-01-01

    The aim of this study was to evaluate the effect of the 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT respiratory gating (4D) study in the correct documentation of pulmonary lesions with faint uptake in standard PET-CT. Forty-two pulmonary lesions with a low or no detectable uptake of FDG (standardized uptake value (SUV) max max was determined for each lesion in both studies. For the 4D studies, we selected the SUV max in respiratory period with the highest uptake ('best bin'). We calculated the SUV max percentage difference between 3D and 4D PET-CT (% difference=SUV max 4D-SUV max 3D/SUV max 3D x 100) and the relation of this value with the size and locations of the lesions. In 4D study, any lesion with SUV max ≥2.5 was classified as malignant. We assessed the changes of lesion classification (from benign to malignant) applying the 4D technique. The final diagnosis was obtained by histological assessment or clinical and radiological follow-up longer than 12 months. Forty out of 42 lesions showed an increase of SUV max in the 4D study with respect to 3D. The mean SUV max in the 3D and 4D PET-CT studies were 1.33 (±0.59) and 2.26 (±0.87), respectively. The SUV max percentage difference mean between both techniques was 83.3% (±80.81). The smaller the lesion the greater was the SUV max percentage difference (P<0.05). No differences were observed depending on the location of the lesion. In 40% of cases, there was a change in the final classification of lesions from benign to malignant. In the final diagnosis, 24 lesions were malignant. 4D PET-CT diagnosed correctly the 52% of them. The 4D PET-CT study permitted a better characterization of malignant lung lesions compared with the standard PET-CT, because of its higher sensitivity. 4D PET-CT is a recommendable technique in the early diagnosis of malignant lesions. (author)

  7. The Analysis of Predictive Factors for the Identification of Patients Who Could Benefit from Respiratory-Gated Radiotherapy in Non-Small Cell Lung Cancer

    International Nuclear Information System (INIS)

    Jang, Seong Soon; Park, Ji Chan

    2009-01-01

    4DCT scans performed for radiotherapy were retrospectively analyzed to assess the possible benefits of respiratory gating in non-small cell lung cancer (NSCLC) and established the predictive factors for identifying patients who could benefit from this approach. Three treatment planning was performed for 15 patients with stage I∼III NSCLC using different planning target volumes (PTVs) as follows: 1) PTVroutine, derived from the addition of conventional uniform margins to gross tumor volume (GTV) of a single bin, 2) PTVall phases (patient-specific PTV), derived from the composite GTV of all 6 bins of the 4DCT, and 3) PTVgating, derived from the composite GTV of 3 consecutive bins at end-exhalation. The reductions in PTV were 43.2% and 9.5%, respectively, for the PTVall phases vs. PTVroutine and PTVgating vs. PTVall phases. Compared to PTVroutine, the use of PTVall phases and PTVgating reduced the mean lung dose (MLD) by 18.1% and 21.6%, and V20 by 18.2% and 22.0%, respectively. Significant correlations were seen between certain predictive factors selected from the tumor mobility and volume analysis, such as the 3D mobility vector, the reduction in 3D mobility and PTV with gating, and the ratio of GTV overlap between 2 extreme bins and additional reductions in both MLD and V20 with gating. The additional benefits with gating compared to the use of patient-specific PTV were modest; however, there were distinct correlations and differences according to the predictive factors. Therefore, these predictive factors might be useful for identifying patients who could benefit from respiratory-gated radiotherapy

  8. SU-E-J-67: Evaluation of Breathing Patterns for Respiratory-Gated Radiation Therapy Using Respiration Regularity Index

    International Nuclear Information System (INIS)

    Cheong, K; Lee, M; Kang, S; Yoon, J; Park, S; Hwang, T; Kim, H; Kim, K; Han, T; Bae, H

    2014-01-01

    Purpose: Despite the importance of accurately estimating the respiration regularity of a patient in motion compensation treatment, an effective and simply applicable method has rarely been reported. The authors propose a simple respiration regularity index based on parameters derived from a correspondingly simplified respiration model. Methods: In order to simplify a patient's breathing pattern while preserving the data's intrinsic properties, we defined a respiration model as a power of cosine form with a baseline drift. According to this respiration formula, breathing-pattern fluctuation could be explained using four factors: sample standard deviation of respiration period, sample standard deviation of amplitude and the results of simple regression of the baseline drift (slope and standard deviation of residuals of a respiration signal. Overall irregularity (δ) was defined as a Euclidean norm of newly derived variable using principal component analysis (PCA) for the four fluctuation parameters. Finally, the proposed respiration regularity index was defined as ρ=ln(1+(1/ δ))/2, a higher ρ indicating a more regular breathing pattern. Subsequently, we applied it to simulated and clinical respiration signals from real-time position management (RPM; Varian Medical Systems, Palo Alto, CA) and investigated respiration regularity. Moreover, correlations between the regularity of the first session and the remaining fractions were investigated using Pearson's correlation coefficient. Results: The respiration regularity was determined based on ρ; patients with ρ 0.7 was suitable for respiratory-gated radiation therapy (RGRT). Fluctuations in breathing cycle and amplitude were especially determinative of ρ. If the respiration regularity of a patient's first session was known, it could be estimated through subsequent sessions. Conclusions: Respiration regularity could be objectively determined using a respiration regularity index, ρ. Such single-index testing of

  9. Observation of Interfractional Variations in Lung Tumor Position Using Respiratory Gated and Ungated Megavoltage Cone-Beam Computed Tomography

    International Nuclear Information System (INIS)

    Chang, Jenghwa; Mageras, Gig S.; Yorke, Ellen; De Arruda, Fernando; Sillanpaa, Jussi; Rosenzweig, Kenneth E.; Hertanto, Agung; Pham, Hai; Seppi, Edward; Pevsner, Alex; Ling, C. Clifton; Amols, Howard

    2007-01-01

    Purpose: To evaluate the use of megavoltage cone-beam computed tomography (MV CBCT) to measure interfractional variation in lung tumor position. Methods and Materials: Eight non-small-cell lung cancer patients participated in the study, 4 with respiratory gating and 4 without. All patients underwent MV CBCT scanning at weekly intervals. Contoured planning CT and MV CBCT images were spatially registered based on vertebral anatomy, and displacements of the tumor centroid determined. Setup error was assessed by comparing weekly portal orthogonal radiographs with digitally reconstructed radiographs generated from planning CT images. Hypothesis testing was performed to test the statistical significance of the volume difference, centroid displacement, and setup uncertainty. Results: The vertebral bodies and soft tissue portions of tumor within lung were visible on the MV CBCT scans. Statistically significant systematic volume decrease over the course of treatment was observed for 1 patient. The average centroid displacement between simulation CT and MV CBCT scans were 2.5 mm, -2.0 mm, and -1.5 mm with standard deviations of 2.7 mm, 2.7 mm, and 2.6 mm in the right-left, anterior-posterior and superior-inferior directions. The mean setup errors were smaller than the centroid shifts, while the standard deviations were comparable. In most cases, the gross tumor volume (GTV) defined on the MV CBCT was located on average at least 5 mm inside a 10 mm expansion of the GTV defined on the planning CT scan. Conclusions: The MV CBCT technique can be used to image lung tumors and may prove valuable for image-guided radiotherapy. Our conclusions must be verified in view of the small patient number

  10. Main technical aspects and clinical benefits of respiratory Gating for radiotherapy of lung neoplasm; Principais aspectos tecnicos e beneficios clinicos do Gating respitatorio para radioterapia do cancer de pulmao

    Energy Technology Data Exchange (ETDEWEB)

    Benites, Rafaela Freitas Oliveira, E-mail: rafaelafreitasfisica@gmail.com [Fundacao do Cancer, Rio de Janeiro, RJ (Brazil)

    2016-07-01

    The concern with the irradiation of lung tumors is that many of them can move along the breathing, which can cause problems in defining accurately the target and increases the irradiation of normal tissues. The objectives are to present the 4D CT principles, image acquisition, reconstruction and application in planning of the radiotherapy. It justifies the quick implantation, improvements in acquisition and images, the possibility in quantify the tumor movement, verifying strategies and delivery treatment. It's concluded that the toxicity risk is reduced with the respiratory gating, and the results suggests that the closed RT will be of clinical relevance. (author)

  11. Real-time prediction and gating of respiratory motion in 3D space using extended Kalman filters and Gaussian process regression network

    Science.gov (United States)

    Bukhari, W.; Hong, S.-M.

    2016-03-01

    The prediction as well as the gating of respiratory motion have received much attention over the last two decades for reducing the targeting error of the radiation treatment beam due to respiratory motion. In this article, we present a real-time algorithm for predicting respiratory motion in 3D space and realizing a gating function without pre-specifying a particular phase of the patient’s breathing cycle. The algorithm, named EKF-GPRN+ , first employs an extended Kalman filter (EKF) independently along each coordinate to predict the respiratory motion and then uses a Gaussian process regression network (GPRN) to correct the prediction error of the EKF in 3D space. The GPRN is a nonparametric Bayesian algorithm for modeling input-dependent correlations between the output variables in multi-output regression. Inference in GPRN is intractable and we employ variational inference with mean field approximation to compute an approximate predictive mean and predictive covariance matrix. The approximate predictive mean is used to correct the prediction error of the EKF. The trace of the approximate predictive covariance matrix is utilized to capture the uncertainty in EKF-GPRN+ prediction error and systematically identify breathing points with a higher probability of large prediction error in advance. This identification enables us to pause the treatment beam over such instances. EKF-GPRN+ implements a gating function by using simple calculations based on the trace of the predictive covariance matrix. Extensive numerical experiments are performed based on a large database of 304 respiratory motion traces to evaluate EKF-GPRN+ . The experimental results show that the EKF-GPRN+ algorithm reduces the patient-wise prediction error to 38%, 40% and 40% in root-mean-square, compared to no prediction, at lookahead lengths of 192 ms, 384 ms and 576 ms, respectively. The EKF-GPRN+ algorithm can further reduce the prediction error by employing the gating function, albeit

  12. Real-time prediction and gating of respiratory motion in 3D space using extended Kalman filters and Gaussian process regression network

    International Nuclear Information System (INIS)

    Bukhari, W; Hong, S-M

    2016-01-01

    The prediction as well as the gating of respiratory motion have received much attention over the last two decades for reducing the targeting error of the radiation treatment beam due to respiratory motion. In this article, we present a real-time algorithm for predicting respiratory motion in 3D space and realizing a gating function without pre-specifying a particular phase of the patient’s breathing cycle. The algorithm, named EKF-GPRN +  , first employs an extended Kalman filter (EKF) independently along each coordinate to predict the respiratory motion and then uses a Gaussian process regression network (GPRN) to correct the prediction error of the EKF in 3D space. The GPRN is a nonparametric Bayesian algorithm for modeling input-dependent correlations between the output variables in multi-output regression. Inference in GPRN is intractable and we employ variational inference with mean field approximation to compute an approximate predictive mean and predictive covariance matrix. The approximate predictive mean is used to correct the prediction error of the EKF. The trace of the approximate predictive covariance matrix is utilized to capture the uncertainty in EKF-GPRN + prediction error and systematically identify breathing points with a higher probability of large prediction error in advance. This identification enables us to pause the treatment beam over such instances. EKF-GPRN + implements a gating function by using simple calculations based on the trace of the predictive covariance matrix. Extensive numerical experiments are performed based on a large database of 304 respiratory motion traces to evaluate EKF-GPRN +  . The experimental results show that the EKF-GPRN + algorithm reduces the patient-wise prediction error to 38%, 40% and 40% in root-mean-square, compared to no prediction, at lookahead lengths of 192 ms, 384 ms and 576 ms, respectively. The EKF-GPRN + algorithm can further reduce the prediction error by employing the gating function

  13. Organ motion study and dosimetric impact of respiratory gating radiotherapy for esophageal cancer; Etude de mobilite organique et impact dosimetrique de l'asservissement respiratoire dans la radiotherapie des cancers de l'oesophage

    Energy Technology Data Exchange (ETDEWEB)

    Lorchel, F

    2007-04-15

    Chemoradiotherapy is now the standard treatment for locally advanced or inoperable esophageal carcinoma. In this indication, conformal radiotherapy is generally used. However, prognosis remains poor for these patients. Respiratory gating radiotherapy can decrease healthy tissues irradiation and allows escalation dose in lung, liver and breast cancer. In order to improve radiotherapy technique, we propose to study the feasibility of respiratory gating for esophageal cancer. We will study the respiratory motions of esophageal cancer to optimize target volume delineation, especially the internal margin (I.M.). We will test the correlation between tumour and chest wall displacements to prove that esophageal cancer motions are induced by respiration. This is essential before using free breathing respiratory gating systems. We will work out the dosimetric impact of respiratory gating using various dosimetric analysis parameters. We will compare dosimetric plans at end expiration, end inspiration and deep inspiration with dosimetric plan in free-breathing condition. This will allow us to establish the best respiratory phase to irradiate for each gating system. This dosimetric study will be completed with linear quadratic equivalent uniform dose (E.U.D.) calculation for each volume of interest. Previously, we will do a theoretical study of histogram dose volume gradation to point up its use. (author)

  14. A Comparison of Amplitude-Based and Phase-Based Positron Emission Tomography Gating Algorithms for Segmentation of Internal Target Volumes of Tumors Subject to Respiratory Motion

    International Nuclear Information System (INIS)

    Jani, Shyam S.; Robinson, Clifford G.; Dahlbom, Magnus; White, Benjamin M.; Thomas, David H.; Gaudio, Sergio; Low, Daniel A.; Lamb, James M.

    2013-01-01

    Purpose: To quantitatively compare the accuracy of tumor volume segmentation in amplitude-based and phase-based respiratory gating algorithms in respiratory-correlated positron emission tomography (PET). Methods and Materials: List-mode fluorodeoxyglucose-PET data was acquired for 10 patients with a total of 12 fluorodeoxyglucose-avid tumors and 9 lymph nodes. Additionally, a phantom experiment was performed in which 4 plastic butyrate spheres with inner diameters ranging from 1 to 4 cm were imaged as they underwent 1-dimensional motion based on 2 measured patient breathing trajectories. PET list-mode data were gated into 8 bins using 2 amplitude-based (equal amplitude bins [A1] and equal counts per bin [A2]) and 2 temporal phase-based gating algorithms. Gated images were segmented using a commercially available gradient-based technique and a fixed 40% threshold of maximum uptake. Internal target volumes (ITVs) were generated by taking the union of all 8 contours per gated image. Segmented phantom ITVs were compared with their respective ground-truth ITVs, defined as the volume subtended by the tumor model positions covering 99% of breathing amplitude. Superior-inferior distances between sphere centroids in the end-inhale and end-exhale phases were also calculated. Results: Tumor ITVs from amplitude-based methods were significantly larger than those from temporal-based techniques (P=.002). For lymph nodes, A2 resulted in ITVs that were significantly larger than either of the temporal-based techniques (P<.0323). A1 produced the largest and most accurate ITVs for spheres with diameters of ≥2 cm (P=.002). No significant difference was shown between algorithms in the 1-cm sphere data set. For phantom spheres, amplitude-based methods recovered an average of 9.5% more motion displacement than temporal-based methods under regular breathing conditions and an average of 45.7% more in the presence of baseline drift (P<.001). Conclusions: Target volumes in images generated

  15. Hypofractionated radiotherapy for invasive bladder cancer

    International Nuclear Information System (INIS)

    Scholten, Astrid N.; Leer, Jan-Willem H.; Collins, C. David; Wondergem, Jan; Hermans, Jo; Timothy, Adrian

    1997-01-01

    Background and purpose: The policy of the Radiotherapy Department of St. Thomas' Hospital in London for patients with invasive bladder cancer, used to be treatment with hypofractionated radiotherapy. The advantages of this fractionation scheme included reduction of the number of treatment sessions and better use of limited resources. Our results after hypofractionation were compared to series with more conventional radiotherapy. Material and methods: Between 1975 and 1985, 123 patients with a T2-T3 transitional cell carcinoma of the bladder were treated by a radical course of hypofractionated radiotherapy. Local control, survival and morbidity rates were analysed retrospectively. Results: The actuarial local control rates at 5 and 10 years were 31 and 29%, respectively. The actuarial cancer-specific 5- and 10-year survival rates were 48 and 39%, respectively. Acute side effects were observed in 87% of patients. The actuarial overall and severe late complication rates at 5 years were 33 and 9%, respectively. The local control, survival and early side effect rates we found, were in the same range as those reported in literature. Late radiation side effects however, were more common after hypofractionated radiotherapy compared to conventional radiotherapy schedules. Conclusions: We conclude that the potential advantage of a reduced number of treatment sessions may be lost in the long term, because of the higher incidence of late morbidity after hypofractionated radiotherapy. Hypofractionation however, remains a valuable technique for palliation and deserves further investigation for radical treatment where access to equipment is difficult or resources are limited

  16. Left ventricular volume measurements with free breathing respiratory self-gated 3-dimensional golden angle radial whole-heart cine imaging - Feasibility and reproducibility.

    Science.gov (United States)

    Holst, Karen; Ugander, Martin; Sigfridsson, Andreas

    2017-11-01

    To develop and evaluate a free breathing respiratory self-gated isotropic resolution technique for left ventricular (LV) volume measurements. A 3D radial trajectory with double golden-angle ordering was used for free-running data acquisition during free breathing in 9 healthy volunteers. A respiratory self-gating signal was extracted from the center of k-space and used with the electrocardiogram to bin all data into 3 respiratory and 25 cardiac phases. 3D image volumes were reconstructed and the LV endocardial border was segmented. LV volume measurements and reproducibility from 3D free breathing cine were compared to conventional 2D breath-held cine. No difference was found between 3D free breathing cine and 2D breath-held cine with regards to LV ejection fraction, stroke volume, end-systolic volume and end-diastolic volume (Pcine and 2D breath-held cine (Pcine and conventional 2D breath-held cine showed similar values and test-retest repeatability for LV volumes in healthy volunteers. 3D free breathing cine enabled retrospective sorting and arbitrary angulation of isotropic data, and could correctly measure LV volumes during free breathing acquisition. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. SU-F-J-158: Respiratory Motion Resolved, Self-Gated 4D-MRI Using Rotating Cartesian K-Space Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Han, F; Zhou, Z; Yang, Y; Sheng, K; Hu, P [UCLA School of Medicine, Los Angeles, CA (United States)

    2016-06-15

    Purpose: Dynamic MRI has been used to quantify respiratory motion of abdominal organs in radiation treatment planning. Many existing 4D-MRI methods based on 2D acquisitions suffer from limited slice resolution and additional stitching artifacts when evaluated in 3D{sup 1}. To address these issues, we developed a 4D-MRI (3D dynamic) technique with true 3D k-space encoding and respiratory motion self-gating. Methods: The 3D k-space was acquired using a Rotating Cartesian K-space (ROCK) pattern, where the Cartesian grid was reordered in a quasi-spiral fashion with each spiral arm rotated using golden angle{sup 2}. Each quasi-spiral arm started with the k-space center-line, which were used as self-gating{sup 3} signal for respiratory motion estimation. The acquired k-space data was then binned into 8 respiratory phases and the golden angle ensures a near-uniform k-space sampling in each phase. Finally, dynamic 3D images were reconstructed using the ESPIRiT technique{sup 4}. 4D-MRI was performed on 6 healthy volunteers, using the following parameters (bSSFP, Fat-Sat, TE/TR=2ms/4ms, matrix size=500×350×120, resolution=1×1×1.2mm, TA=5min, 8 respiratory phases). Supplemental 2D real-time images were acquired in 9 different planes. Dynamic locations of the diaphragm dome and left kidney were measured from both 4D and 2D images. The same protocol was also performed on a MRI-compatible motion phantom where the motion was programmed with different amplitude (10–30mm) and frequency (3–10/min). Results: High resolution 4D-MRI were obtained successfully in 5 minutes. Quantitative motion measurements from 4D-MRI agree with the ones from 2D CINE (<5% error). The 4D images are free of the stitching artifacts and their near-isotropic resolution facilitates 3D visualization and segmentation of abdominal organs such as the liver, kidney and pancreas. Conclusion: Our preliminary studies demonstrated a novel ROCK 4D-MRI technique with true 3D k-space encoding and respiratory

  18. Residual motion of lung tumors in end-of-inhale respiratory gated radiotherapy based on external surrogates

    International Nuclear Information System (INIS)

    Berbeco, Ross I.; Nishioka, Seiko; Shirato, Hiroki; Jiang, Steve B.

    2006-01-01

    It has been noted that some lung tumors exhibit large periodic motion due to respiration. To limit the amount of dose to healthy lung tissues, many clinics have begun gating radiotherapy treatment using externally placed surrogates. It has been observed by several institutions that the end-of-exhale (EOE) tumor position is more reproducible than other phases of the breathing cycle, so the gating window is often set there. From a treatment planning perspective, end-of-inhale (EOI) phase might be preferred for gating because the expanded lungs will further decrease the healthy tissue within the treatment field. We simulate gated treatment at the EOI phase, using a set of recently measured internal/external anatomy patient data. This paper attempts to answer three questions: (1) How much is the tumor residual motion when we use an external surrogate gating window at EOI? (2) How could we reduce the residual motion in the EOI gating window? (3) Is there a preference for amplitude- versus phase-based gating at EOI? We found that under free breathing conditions the residual motion of the tumors is much larger for EOI phase than for EOE phase. The mean values of residual motion at EOI were found to be 2.2 and 2.7 mm for amplitude- and phase-based gating, respectively, and, at EOE, 1.0 and 1.2 mm for amplitude- and phase-based gating, respectively. However, we note that the residual motion in the EOI gating window is correlated well with the reproducibility of the external surface position in the EOI phase. Using the results of a published breath-coaching study, we deduce that the residual motion of a lung tumor at EOI would approach that at EOE, with the same duty cycle (30%), under breath-coaching conditions. Additionally, we found that under these same conditions, phase-based gating approaches the same residual motion as amplitude-based gating, going from a 28% difference to 11%, for the patient with the largest difference between the two gating modalities. We conclude

  19. SU-E-J-67: Evaluation of Breathing Patterns for Respiratory-Gated Radiation Therapy Using Respiration Regularity Index

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, K; Lee, M; Kang, S; Yoon, J; Park, S; Hwang, T; Kim, H; Kim, K; Han, T; Bae, H [Hallym University College of Medicine, Anyang (Korea, Republic of)

    2014-06-01

    Purpose: Despite the importance of accurately estimating the respiration regularity of a patient in motion compensation treatment, an effective and simply applicable method has rarely been reported. The authors propose a simple respiration regularity index based on parameters derived from a correspondingly simplified respiration model. Methods: In order to simplify a patient's breathing pattern while preserving the data's intrinsic properties, we defined a respiration model as a power of cosine form with a baseline drift. According to this respiration formula, breathing-pattern fluctuation could be explained using four factors: sample standard deviation of respiration period, sample standard deviation of amplitude and the results of simple regression of the baseline drift (slope and standard deviation of residuals of a respiration signal. Overall irregularity (δ) was defined as a Euclidean norm of newly derived variable using principal component analysis (PCA) for the four fluctuation parameters. Finally, the proposed respiration regularity index was defined as ρ=ln(1+(1/ δ))/2, a higher ρ indicating a more regular breathing pattern. Subsequently, we applied it to simulated and clinical respiration signals from real-time position management (RPM; Varian Medical Systems, Palo Alto, CA) and investigated respiration regularity. Moreover, correlations between the regularity of the first session and the remaining fractions were investigated using Pearson's correlation coefficient. Results: The respiration regularity was determined based on ρ; patients with ρ<0.3 showed worse regularity than the others, whereas ρ>0.7 was suitable for respiratory-gated radiation therapy (RGRT). Fluctuations in breathing cycle and amplitude were especially determinative of ρ. If the respiration regularity of a patient's first session was known, it could be estimated through subsequent sessions. Conclusions: Respiration regularity could be objectively determined

  20. Evaluation of a direct motion estimation/correction method in respiratory-gated PET/MRI with motion-adjusted attenuation.

    Science.gov (United States)

    Bousse, Alexandre; Manber, Richard; Holman, Beverley F; Atkinson, David; Arridge, Simon; Ourselin, Sébastien; Hutton, Brian F; Thielemans, Kris

    2017-06-01

    Respiratory motion compensation in PET/CT and PET/MRI is essential as motion is a source of image degradation (motion blur, attenuation artifacts). In previous work, we developed a direct method for joint image reconstruction/motion estimation (JRM) for attenuation-corrected (AC) respiratory-gated PET, which uses a single attenuation-map (μ-map). This approach was successfully implemented for respiratory-gated PET/CT, but since it relied on an accurate μ-map for motion estimation, the question of its applicability in PET/MRI is open. The purpose of this work is to investigate the feasibility of JRM in PET/MRI and to assess the robustness of the motion estimation when a degraded μ-map is used. We performed a series of JRM reconstructions from simulated PET data using a range of simulated Dixon MRI sequence derived μ-maps with wrong attenuation values in the lungs, from -100% (no attenuation) to +100% (double attenuation), as well as truncated arms. We compared the estimated motions with the one obtained from JRM in ideal conditions (no noise, true μ-map as an input). We also applied JRM on 4 patient datasets of the chest, 3 of them containing hot lesions. Patient list-mode data were gated using a principal component analysis method. We compared SUV max values of the JRM reconstructed activity images and non motion-corrected images. We also assessed the estimated motion fields by comparing the deformed JRM-reconstructed activity with individually non-AC reconstructed gates. Experiments on simulated data showed that JRM-motion estimation is robust to μ-map degradation in the sense that it produces motion fields similar to the ones obtained when using the true μ-map, regardless of the attenuation errors in the lungs (PET/MRI clinical datasets. It provides a potential alternative to existing methods where the motion fields are pre-estimated from separate MRI measurements. © 2017 University College London (UCL). Medical Physics published by Wiley Periodicals, Inc

  1. The Impact of Optimal Respiratory Gating and Image Noise on Evaluation of Intratumor Heterogeneity on 18F-FDG PET Imaging of Lung Cancer.

    Science.gov (United States)

    Grootjans, Willem; Tixier, Florent; van der Vos, Charlotte S; Vriens, Dennis; Le Rest, Catherine C; Bussink, Johan; Oyen, Wim J G; de Geus-Oei, Lioe-Fee; Visvikis, Dimitris; Visser, Eric P

    2016-11-01

    Accurate measurement of intratumor heterogeneity using parameters of texture on PET images is essential for precise characterization of cancer lesions. In this study, we investigated the influence of respiratory motion and varying noise levels on quantification of textural parameters in patients with lung cancer. We used an optimal-respiratory-gating algorithm on the list-mode data of 60 lung cancer patients who underwent 18 F-FDG PET. The images were reconstructed using a duty cycle of 35% (percentage of the total acquired PET data). In addition, nongated images of varying statistical quality (using 35% and 100% of the PET data) were reconstructed to investigate the effects of image noise. Several global image-derived indices and textural parameters (entropy, high-intensity emphasis, zone percentage, and dissimilarity) that have been associated with patient outcome were calculated. The clinical impact of optimal respiratory gating and image noise on assessment of intratumor heterogeneity was evaluated using Cox regression models, with overall survival as the outcome measure. The threshold for statistical significance was adjusted for multiple comparisons using Bonferroni correction. In the lower lung lobes, respiratory motion significantly affected quantification of intratumor heterogeneity for all textural parameters (P 0.007). The mean increase in entropy, dissimilarity, zone percentage, and high-intensity emphasis was 1.3% ± 1.5% (P = 0.02), 11.6% ± 11.8% (P = 0.006), 2.3% ± 2.2% (P = 0.002), and 16.8% ± 17.2% (P = 0.006), respectively. No significant differences were observed for lesions in the upper lung lobes (P > 0.007). Differences in the statistical quality of the PET images affected the textural parameters less than respiratory motion, with no significant difference observed. The median follow-up time was 35 mo (range, 7-39 mo). In multivariate analysis for overall survival, total lesion glycolysis and high-intensity emphasis were the two most

  2. Estimation of patient-specific imaging dose for real-time tumour monitoring in lung patients during respiratory-gated radiotherapy

    Science.gov (United States)

    Shiinoki, Takehiro; Onizuka, Ryota; Kawahara, Daisuke; Suzuki, Tatsuhiko; Yuasa, Yuki; Fujimoto, Koya; Uehara, Takuya; Hanazawa, Hideki; Shibuya, Keiko

    2018-03-01

    Purpose: To quantify the patient-specific imaging dose for real-time tumour monitoring in the lung during respiratory-gated stereotactic body radiotherapy (SBRT) in clinical cases using SyncTraX. Methods and Materials: Ten patients who underwent respiratory-gated SBRT with SyncTraX were enrolled in this study. The imaging procedure for real-time tumour monitoring using SyncTraX was simulated using Monte Carlo. We evaluated the dosimetric effect of a real-time tumour monitoring in a critical organ at risk (OAR) and the planning target volume (PTV) over the course of treatment. The relationship between skin dose and gating efficiency was also investigated. Results: For all patients, the mean D50 to the PTV, ipsilateral lung, liver, heart, spinal cord and skin was 118.3 (21.5–175.9), 31.9 (9.5–75.4), 15.4 (1.1–31.6), 10.1 (1.3–18.1), 25.0 (1.6–101.8), and 3.6 (0.9–7.1) mGy, respectively. The mean D2 was 352.0 (26.5–935.8), 146.4 (27.3–226.7), 90.7 (3.6–255.0), 42.2 (4.8–82.7), 88.0 (15.4–248.5), and 273.5 (98.3–611.6) mGy, respectively. The D2 of the skin dose was found to increase as the gating efficiency decreased. Conclusions: The additional dose to the PTV was at most 1.9% of the prescribed dose over the course of treatment for real-time tumour monitoring. For OARs, we could confirm the high dose region, which may not be susceptible to radiation toxicity. However, to reduce the skin dose from SyncTraX, it is necessary to increase the gating efficiency.

  3. Comparative evaluation of respiratory-gated and ungated FDG-PET for target volume definition in radiotherapy treatment planning for pancreatic cancer.

    Science.gov (United States)

    Kishi, Takahiro; Matsuo, Yukinori; Nakamura, Akira; Nakamoto, Yuji; Itasaka, Satoshi; Mizowaki, Takashi; Togashi, Kaori; Hiraoka, Masahiro

    2016-08-01

    The purpose of this study was to evaluate the usefulness of respiratory-gated positron emission tomography (4D-PET) in pancreatic cancer radiotherapy treatment planning (RTTP). Fourteen patients with 18F-fluorodeoxyglucose (FDG)-avid pancreatic tumours were evaluated between December 2013 and March 2015. Two sets of volumes were contoured for the pancreatic tumour of each patient. The biological target volume in three-dimensional RTTP (BTV3D) was contoured using conventional respiratory un-gated PET. The BTV3D was then expanded using population-based margins to generate a series of internal target volume 3D (ITV3D) values. The ITV 4D (ITV4D) was contoured using 4D-PET. Each of the five phases of 4D-PET was used for 4D contouring, and the ITV4D was constructed by summing the volumes defined on the five individual 4D-PET images. The relative volumes and normalized volumetric overlap were computed between ITV3D and ITV4D. On average, the FDG-avid tumour volumes were 1.6 (range: 0.8-2.3) fold greater in the ITV4D than in the BTV3D. On average, the ITV3D values were 2.0 (range: 1.1-3.4) fold larger than the corresponding ITV4D values. The ITV generated from 4D-PET can be used to improve the accuracy or reduce normal tissue irradiation compared with conventional un-gated PET-based ITV. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. 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.

  5. Magnetic resonance imaging of the coronary arteries: clinical results from three dimensional evaluation of a respiratory gated technique

    NARCIS (Netherlands)

    R.J.M. van Geuns (Robert Jan); H.G. de Bruin (Hein); B.J.W.M. Rensing (Benno); P.A. Wielopolski (Piotr); M.D. Hulshoff; P.M.A. van Ooijen (Peter); M. Oudkerk (Matthijs); P.J. de Feyter (Pim)

    1999-01-01

    textabstractBACKGROUND: Magnetic resonance coronary angiography is challenging because of the motion of the vessels during cardiac contraction and respiration. Additional challenges are the small calibre of the arteries and their complex three dimensional course. Respiratory

  6. Respiratory gated PET/CT of the liver: A novel method and its impact on the detection of colorectal liver metastases

    International Nuclear Information System (INIS)

    Schulz, Anselm; Godt, Johannes Clemens; Dormagen, Johann Baptist; Holtedahl, Jon Erik; Bogsrud, Trond Velde; Labori, Knut Jørgen; Kløw, Nils-Einar; Bach-Gansmo, Tore

    2015-01-01

    Highlights: • Combined PET/CT and respiratory gated PET/CT improved sensitivity significantly. • Respiratory gated PET/CT had greatest impact on detection of small CRLM <10 mm. • Our results were comparable to earlier reported more complex and expensive methods. • The method used is inexpensive and requires only limited additional imaging time. - Abstract: Purpose: To evaluate the diagnostic performance of a new method for respiratory gated positron emission tomography (rgPET/CT) for colorectal liver metastases (CRLM), secondly, to assess its additional value to standard PET/CT (PET/CT). Materials and methods: Forty-three patients scheduled for resection of suspected CRLM were prospectively included from September 2011 to January 2013. None of the patients had previously undergone treatment for their CRLM. All patients underwent PET/CT and rgPET/CT in the same session. For rgPET/CT an in-house developed electronic circuit was used which displayed a color-coded countdown for the patient. The patients held their breath according to the countdown and only the data from the inspiration breath-hold period was used for image reconstruction. Two independent and blinded readers evaluated both PET/CT and rgPET/CT separately. The reference standard was histopathological confirmation for 73 out of 131 CRLM and follow-up otherwise. Results: Reference standard identified 131 CRLM in 39/43 patients. Nine patients accounted for 25 mucinous CRLM. The overall per-lesion sensitivity for detection of CRLM was for PET/CT 60.0%, for rgPET/CT 63.1%, and for standard + rgPET/CT 67.7%, respectively. Standard + rgPET/CT was overall significantly more sensitive for CRLM compared to PET/CT (p = 0.002) and rgPET/CT (p = 0.031). The overall positive predictive value (PPV) for detection of CRLM was for PET/CT 97.5%, for rgPET/CT 95.3%, and for standard + rgPET/CT 93.6%, respectively. Conclusion: Combination of PET/CT and rgPET/CT improved the sensitivity significantly for CRLM. However

  7. Respiratory gated PET/CT of the liver: A novel method and its impact on the detection of colorectal liver metastases

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Anselm, E-mail: anselm.schulz@gmail.com [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Institute of Clinical Medicine, University of Oslo, P.O. Box 1171 Blindern, 0318 Oslo (Norway); Godt, Johannes Clemens, E-mail: UXGODJ@ous-hf.no [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Institute of Clinical Medicine, University of Oslo, P.O. Box 1171 Blindern, 0318 Oslo (Norway); Dormagen, Johann Baptist, E-mail: UXJORM@ous-hf.no [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Holtedahl, Jon Erik, E-mail: JONHOL@ous-hf.no [The Intervention Centre, Oslo University Hospital, Postboks 4950 Nydalen, 0424 Oslo (Norway); Bogsrud, Trond Velde, E-mail: tvbog@aol.com [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Department of Nuclear Medicine and PET-Center, Aarhus University Hospital, Norrebrogade 44, DK-8000 Aarhus C (Denmark); Labori, Knut Jørgen, E-mail: uxknab@ous-hf.no [Department of Hepato-Pancreato-Biliary Surgery, Oslo University Hospital, Postboks 4950 Nydalen, 0424 Oslo (Norway); Kløw, Nils-Einar, E-mail: NILKLO@ous-hf.no [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Institute of Clinical Medicine, University of Oslo, P.O. Box 1171 Blindern, 0318 Oslo (Norway); Bach-Gansmo, Tore, E-mail: bat@ous-hf.no [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway)

    2015-08-15

    Highlights: • Combined PET/CT and respiratory gated PET/CT improved sensitivity significantly. • Respiratory gated PET/CT had greatest impact on detection of small CRLM <10 mm. • Our results were comparable to earlier reported more complex and expensive methods. • The method used is inexpensive and requires only limited additional imaging time. - Abstract: Purpose: To evaluate the diagnostic performance of a new method for respiratory gated positron emission tomography (rgPET/CT) for colorectal liver metastases (CRLM), secondly, to assess its additional value to standard PET/CT (PET/CT). Materials and methods: Forty-three patients scheduled for resection of suspected CRLM were prospectively included from September 2011 to January 2013. None of the patients had previously undergone treatment for their CRLM. All patients underwent PET/CT and rgPET/CT in the same session. For rgPET/CT an in-house developed electronic circuit was used which displayed a color-coded countdown for the patient. The patients held their breath according to the countdown and only the data from the inspiration breath-hold period was used for image reconstruction. Two independent and blinded readers evaluated both PET/CT and rgPET/CT separately. The reference standard was histopathological confirmation for 73 out of 131 CRLM and follow-up otherwise. Results: Reference standard identified 131 CRLM in 39/43 patients. Nine patients accounted for 25 mucinous CRLM. The overall per-lesion sensitivity for detection of CRLM was for PET/CT 60.0%, for rgPET/CT 63.1%, and for standard + rgPET/CT 67.7%, respectively. Standard + rgPET/CT was overall significantly more sensitive for CRLM compared to PET/CT (p = 0.002) and rgPET/CT (p = 0.031). The overall positive predictive value (PPV) for detection of CRLM was for PET/CT 97.5%, for rgPET/CT 95.3%, and for standard + rgPET/CT 93.6%, respectively. Conclusion: Combination of PET/CT and rgPET/CT improved the sensitivity significantly for CRLM. However

  8. Quality assurance program of a respiratory gating irradiation system based on external and internal fiducial markers; Programa de garantia de calidad de un sistema de irradiacion con control respiratorio basado en marcadores fiduciales externos e internos

    Energy Technology Data Exchange (ETDEWEB)

    Zucca Aparicio, D.; Perez Moreno, J. M.; Fernandez Leton, P.; Garcia Ruiz-Zorrilla, J.; Minambres Moro, A.

    2011-07-01

    Respiratory Gating involves the administration of radiation during treatment delivery within a particular portion of the patients breathing cycle, so the absorbed dose administration with respiratory control techniques requires specific quality control to ensure the correctness of the delivered dose. The establishment of a Quality Control Program (QC) is proposed for the Respiratory Gating based techniques in order to have a better understanding of how this system works and to know its associated dosimetric impact. The influence of the CT acquisition under respiratory motion conditions has been analyzed for the treatment isocenter localization, using internal and external fiducial markers with IGRT techniques that allow the correlation of the isocenter positioning with the phase of the respiratory cycle. Radiation delivery in the presence of intra fraction organ motion causes an averaging or blurring of the static dose distribution over the path of motion increasing the beam penumbra of the radiation field and reducing the therapeutic region when the irradiation is not breath controlled. The feasibility of intensity modulated treatments (IMRT) for both static and dynamic techniques, managed by respiratory control has been tested, demonstrating the possibility of synchronizing the movement of the leaves in the microfluorimeter collimator (mMLC) with the gated beam irradiation. (Author) 45 refs.

  9. A statistical method for retrospective cardiac and respiratory motion gating of interventional cardiac x-ray images

    Energy Technology Data Exchange (ETDEWEB)

    Panayiotou, Maria, E-mail: maria.panayiotou@kcl.ac.uk; King, Andrew P.; Housden, R. James; Ma, YingLiang; Rhode, Kawal S. [Division of Imaging Sciences and Biomedical Engineering, King' s College London, London SE1 7EH (United Kingdom); Cooklin, Michael; O' Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo [Department of Cardiology, Guy' s and St. Thomas' Hospitals NHS Foundation Trust, London SE1 7EH (United Kingdom)

    2014-07-15

    Purpose: Image-guided cardiac interventions involve the use of fluoroscopic images to guide the insertion and movement of interventional devices. Cardiorespiratory gating can be useful for 3D reconstruction from multiple x-ray views and for reducing misalignments between 3D anatomical models overlaid onto fluoroscopy. Methods: The authors propose a novel and potentially clinically useful retrospective cardiorespiratory gating technique. The principal component analysis (PCA) statistical method is used in combination with other image processing operations to make our proposed masked-PCA technique suitable for cardiorespiratory gating. Unlike many previously proposed techniques, our technique is robust to varying image-content, thus it does not require specific catheters or any other optically opaque structures to be visible. Therefore, it works without any knowledge of catheter geometry. The authors demonstrate the application of our technique for the purposes of retrospective cardiorespiratory gating of normal and very low dose x-ray fluoroscopy images. Results: For normal dose x-ray images, the algorithm was validated using 28 clinical electrophysiology x-ray fluoroscopy sequences (2168 frames), from patients who underwent radiofrequency ablation (RFA) procedures for the treatment of atrial fibrillation and cardiac resynchronization therapy procedures for heart failure. The authors established end-systole, end-expiration, and end-inspiration success rates of 97.0%, 97.9%, and 97.0%, respectively. For very low dose applications, the technique was tested on ten x-ray sequences from the RFA procedures with added noise at signal to noise ratio (SNR) values of√(5)0, √(1)0, √(8), √(6), √(5), √(2), and √(1) to simulate the image quality of increasingly lower dose x-ray images. Even at the low SNR value of √(2), representing a dose reduction of more than 25 times, gating success rates of 89.1%, 88.8%, and 86.8% were established. Conclusions: The proposed

  10. Procedural sedation and analgesia for respiratory-gated MR-HIFU in the liver : a feasibility study

    NARCIS (Netherlands)

    van Breugel, Marjolein; Wijlemans, JW; Vaessen, Hermanus H B; de Greef, Martijn; Moonen, Chrit T W; van den Bosch, Maurice A A J; Ries, Mario G

    2016-01-01

    BACKGROUND: Previous studies demonstrated both pre-clinically and clinically the feasibility of magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablations in the liver. To overcome the associated problem of respiratory motion of the ablation area, general anesthesia (GA) and

  11. Interfractional changes in tumour volume and position during entire radiotherapy courses for lung cancer with respiratory gating and image guidance

    DEFF Research Database (Denmark)

    Juhler-Nøttrup, Trine; Korreman, Stine Sofia; Pedersen, Anders N

    2008-01-01

    were contoured on each CT scan to evaluate the variations in volumes and position. The lung tumours and the mediastinal tumours were contoured separately. The positional variations were measured as 3D mobility vectors and correlated to matching of the scans using the two different strategies. RESULTS......-87% when matched using bony landmarks and 70-76% when matched using skin tattoos. The overlap of the mediastinal tumours were 60-65% and 41-47%, respectively. CONCLUSIONS: Despite the use of gating the tumours varied considerably, regarding both position and volume. The variations in position were...

  12. Feasibility of deep-inspiration breath-hold PET/CT with short-time acquisition. Detectability for pulmonary lesions compared with respiratory-gated PET/CT

    International Nuclear Information System (INIS)

    Yamashita, Shozo; Yamamoto, Haruki; Hiko, Shigeaki; Horita, Akihiro; Yokoyama, Kunihiko; Onoguchi, Masahisa; Nakajima, Kenichi

    2014-01-01

    Deep-inspiration breath-hold (DIBH) positron emission tomography (PET)/CT with short-time acquisition and respiratory-gated (RG) PET/CT are performed for pulmonary lesions to reduce the respiratory motion artifacts, and to obtain more accurate standardized uptake value (SUV). DIBH PET/CT demonstrates significant advantages in terms of rapid examination, good quality of CT images and low radiation exposure. On the other hand, the image quality of DIBH PET is generally inferior to that of RG PET because of short-time acquisition resulting in poor signal-to-noise ratio. In this study, RG PET has been regarded as a gold standard, and its detectability between DIBH and RG PET studies was compared using each of the most optimal reconstruction parameters. In the phantom study, the most optimal reconstruction parameters for DIBH and RG PET were determined. In the clinical study, 19 cases were examined using each of the most optimal reconstruction parameters. In the phantom study, the most optimal reconstruction parameters for DIBH and RG PET were different. Reconstruction parameters of DIBH PET could be obtained by reducing the number of subsets for those of RG PET in the state of fixing the number of iterations. In the clinical study, high correlation in the maximum SUV was observed between DIBH and RG PET studies. The clinical result was consistent with that of the phantom study surrounded by air since most of the lesions were located in the low pulmonary radioactivity. DIBH PET/CT may be the most practical method which can be the first choice to reduce respiratory motion artifacts if the detectability of DIBH PET is equivalent with that of RG PET. Although DIBH PET may have limitations in suboptimal signal-to-noise ratio, most of the lesions surrounded by low background radioactivity could provide nearly equivalent image quality between DIBH and RG PET studies when each of the most optimal reconstruction parameters was used. (author)

  13. Stereotactic Radiosurgery and Hypofractionated Radiotherapy for Glioblastoma.

    Science.gov (United States)

    Shah, Jennifer L; Li, Gordon; Shaffer, Jenny L; Azoulay, Melissa I; Gibbs, Iris C; Nagpal, Seema; Soltys, Scott G

    2018-01-01

    Glioblastoma is the most common primary brain tumor in adults. Standard therapy depends on patient age and performance status but principally involves surgical resection followed by a 6-wk course of radiation therapy given concurrently with temozolomide chemotherapy. Despite such treatment, prognosis remains poor, with a median survival of 16 mo. Challenges in achieving local control, maintaining quality of life, and limiting toxicity plague treatment strategies for this disease. Radiotherapy dose intensification through hypofractionation and stereotactic radiosurgery is a promising strategy that has been explored to meet these challenges. We review the use of hypofractionated radiotherapy and stereotactic radiosurgery for patients with newly diagnosed and recurrent glioblastoma. Copyright © 2017 by the Congress of Neurological Surgeons.

  14. Respiratory motion-resolved, self-gated 4D-MRI using Rotating Cartesian K-space (ROCK): Initial clinical experience on an MRI-guided radiotherapy system.

    Science.gov (United States)

    Han, Fei; Zhou, Ziwu; Du, Dongsu; Gao, Yu; Rashid, Shams; Cao, Minsong; Shaverdian, Narek; Hegde, John V; Steinberg, Michael; Lee, Percy; Raldow, Ann; Low, Daniel A; Sheng, Ke; Yang, Yingli; Hu, Peng

    2018-06-01

    To optimize and evaluate the respiratory motion-resolved, self-gated 4D-MRI using Rotating Cartesian K-space (ROCK-4D-MRI) method in a 0.35 T MRI-guided radiotherapy (MRgRT) system. The study included seven patients with abdominal tumors treated on the MRgRT system. ROCK-4D-MRI and 2D-CINE, was performed immediately after one of the treatment fractions. Motion quantification based on 4D-MRI was compared with those based on 2D-CINE. The image quality of 4D-MRI was evaluated against 4D-CT. The gross tumor volumes (GTV) were defined based on individual respiratory phases of both 4D-MRI and 4D-CT and compared for their variability over the respiratory cycle. The motion measurements based on 4D-MRI matched well with 2D-CINE, with differences of 1.04 ± 0.52 mm in the superior-inferior and 0.54 ± 0.21 mm in the anterior-posterior directions. The image quality scores of 4D-MRI were significantly higher than 4D-CT, with better tumor contrast (3.29 ± 0.76 vs. 1.86 ± 0.90) and less motion artifacts (3.57 ± 0.53 vs. 2.29 ± 0.95). The GTVs were more consistent in 4D-MRI than in 4D-CT, with significantly smaller GTV variability (9.31 ± 4.58% vs. 34.27 ± 23.33%). Our study demonstrated the clinical feasibility of using the ROCK-4D-MRI to acquire high quality, respiratory motion-resolved 4D-MRI in a low-field MRgRT system. The 4D-MRI image could provide accurate dynamic information for radiotherapy treatment planning. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Hypofractionated radiotherapy for localized prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hoecht, Stefan [Xcare Gruppe, Radiologie, Nuklearmedizin und Strahlentherapie, Saarlouis (Germany); Aebersold, Daniel M. [University of Bern, Universitaetsklinik fuer Radio-Onkologie, Inselspital, Bern (Switzerland); Albrecht, Clemens [Universitaetsklinikum der Paracelsus Medizinischen Privatuniversitaet, Klinik fuer Radioonkologie und Gemeinschaftspraxis fuer Strahlentherapie, Klinikum Nuernberg Nord, Nuremberg (Germany); Boehmer, Dirk [Charite Universitaetsmedizin, Klinik fuer Radioonkologie und Strahlentherapie, Berlin (Germany); Flentje, Michael [Universitaetsklinikum Wuerzburg, Klinik und Poliklinik fuer Strahlentherapie, Wuerzburg (Germany); Ganswindt, Ute [Ludwig-Maximilians-Universitaet Muenchen, Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie, Munich (Germany); Hoelscher, Tobias [Universitaetsklinikum Carl Gustav Carus, Technische Universitaet Dresden, Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie, Dresden (Germany); Martin, Thomas [Klinikum Bremen-Mitte, Klinik fuer Strahlentherapie und Radioonkologie, Bremen (Germany); Sedlmayer, Felix [Universitaetsklinikum der Paracelsus Medizinischen Privatuniversitaet, Universitaetsklinik fuer Radiotherapie und Radio-Onkologie, Landeskrankenhaus, Salzburg (Austria); Wenz, Frederik [Universitaetsmedizin Mannheim, Universitaet Heidelberg, Klinik fuer Strahlentherapie und Radioonkologie, Mannheim (Germany); Zips, Daniel [Universitaetsklinikum Tuebingen, Universitaetsklinik fuer Radioonkologie, Tuebingen (Germany); Wiegel, Thomas [Universitaetsklinikum Ulm, Abteilung Strahlentherapie, Ulm (Germany)

    2017-01-15

    This article gives an overview on the current status of hypofractionated radiotherapy in the treatment of prostate cancer with a special focus on the applicability in routine use. Based on a recently published systematic review the German Society of Radiation Oncology (DEGRO) expert panel added additional information that has become available since then and assessed the validity of the information on outcome parameters especially with respect to long-term toxicity and long-term disease control. Several large-scale trials on moderate hypofractionation with single doses from 2.4-3.4 Gy have recently finished recruiting or have published first results suggestive of equivalent outcomes although there might be a trend for increased short-term and possibly even long-term toxicity. Large phase 3 trials on extreme hypofractionation with single doses above 4.0 Gy are lacking and only very few prospective trials have follow-up periods covering more than just 2-3 years. Until the results on long-term follow-up of several well-designed phase 3 trials become available, moderate hypofractionation should not be used in routine practice without special precautions and without adherence to the highest quality standards and evidence-based dose fractionation regimens. Extreme hypofractionation should be restricted to prospective clinical trials. (orig.) [German] Diese Uebersichtsarbeit soll den aktuellen Status der hypofraktionierten Radiotherapie des Prostatakarzinoms mit dem Fokus auf die Anwendung in der Routinetherapie darstellen. Basierend auf einem kuerzlich erschienen systematischen Review zur Hypofraktionierung sind durch das DEGRO Expertengremium zusaetzliche, in der Zwischenzeit verfuegbar gewordene Informationen mit beruecksichtigt worden. Die Validitaet der Aussagen zu Ergebnissen wurde speziell im Hinblick auf die Langzeittoxizitaet und -erkrankungskontrolle bewertet. Mehrere grosse Phase-3-Studien zur moderaten Hypofraktionierung mit Dosen von 2,4-3,4 Gy pro Fraktion

  16. Respiratory gated PET/CT in a European multicentre retrospective study: added diagnostic value in detection and characterization of lung lesions

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, Luca; Elisei, Federica [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); De Ponti, Elena [San Gerardo Hospital, Medical Physics, Monza (Italy); Bettinardi, Valentino; Picchio, Maria [San Raffaele Scientific Institute, Nuclear Medicine, Milan (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy); Landoni, Claudio [San Raffaele Scientific Institute, Nuclear Medicine, Milan (Italy); University of Milano-Bicocca, Milan (Italy); Gilardi, Maria Carla [San Raffaele Scientific Institute, Nuclear Medicine, Milan (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy); University of Milano-Bicocca, Tecnomed Foundation, Milan (Italy); Versari, Annibale [Scientific Institute Santa Maria Nuova Hospital, Nuclear Medicine, Reggio Emilia (Italy); Fioroni, Federica [Scientific Institute Santa Maria Nuova Hospital, Medical Physics, Reggio Emilia (Italy); Dziuk, Miroslaw [Masovian PET-CT Centre, Department of Nuclear Medicine, Military Institute of Medicine, Warsaw (Poland); Koza, Magdalena [Masovian PET-CT Centre, Euromedic Diagnostic, Warsaw (Poland); Ahond-Vionnet, Renee; Collin, Bertrand [Hopital Pierre Beregovoy, Service de Medecine Nucleaire, Nevers (France); Messa, Cristina [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy); University of Milano-Bicocca, Tecnomed Foundation, Milan (Italy)

    2012-09-15

    The aim of our work is to evaluate the added diagnostic value of respiratory gated (4-D) positron emission tomography/computed tomography (PET/CT) in lung lesion detection/characterization in a large patient population of a multicentre retrospective study. The data of 155 patients (89 men, 66 women, mean age 63.9 {+-} 11.1 years) from 5 European centres and submitted to standard (3-D) and 4-D PET/CT were retrospectively analysed. Overall, 206 lung lesions were considered for the analysis (mean {+-} SD lesions dimension 14.7 {+-} 11.8 mm). Maximum standardized uptake values (SUV{sub max}) and lesion detectability were assessed for both 3-D and 4-D PET/CT studies; 3-D and 4-D PET/CT findings were compared to clinical follow-up as standard reference. Mean {+-} SD 3-D and 4-D SUV{sub max} values were 5.2 {+-} 5.1 and 6.8 {+-} 6.1 (p < 0.0001), respectively, with an average percentage increase of 30.8 %. In 3-D PET/CT, 86 of 206 (41.7 %) lesions were considered positive, 70 of 206 (34 %) negative and 50 of 206 (24.3 %) equivocal, while in 4-D PET/CT 117 of 206 (56.8 %) lesions were defined as positive, 80 of 206 (38.8 %) negative and 9 of 206 (4.4 %) equivocal. In 34 of 50 (68 %) 3-D equivocal lesions follow-up data were available and the presence of malignancy was confirmed in 21 of 34 (61.8 %) lesions, while in 13 of 34 (38.2 %) was excluded. In 31 of these 34 controlled lesions, 20 of 34 (58.8 %) and 11 of 34 (32.4 %) were correctly classified by 4-D PET/CT as positive and negative, respectively; 3 of 34 (8.8 %) remained equivocal. With equivocal lesions classified as positive, the overall accuracy of 3-D and 4-D was 85.7 and 92.8 %, respectively, while the same figures were 80.5 and 94.2 % when equivocal lesions were classified as negative. The respiratory gated PET/CT technique is a valuable clinical tool in diagnosing lung lesions, improving quantification and confidence in reporting, reducing 3-D undetermined findings and increasing the overall accuracy in lung

  17. Added diagnostic value of respiratory-gated 4D 18F-FDG PET/CT in the detection of liver lesions. A multicenter study

    Energy Technology Data Exchange (ETDEWEB)

    Crivellaro, Cinzia; Landoni, Claudio; Guerra, Luca [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); University of Milan-Bicocca, Milan (Italy); De Ponti, Elena; Morzenti, Sabrina [San Gerardo Hospital, Medical Physics, Monza (Italy); Elisei, Federica [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); Picchio, Maria; Bettinardi, Valentino [IRCCS San Raffaele Scientific Institute, Nuclear Medicine, Milan (Italy); Versari, Annibale [Santa Maria Nuova Hospital IRCCS, Nuclear Medicine, Reggio Emilia (Italy); Fioroni, Federica [Santa Maria Nuova Hospital IRCCS, Medical Physics, Reggio Emilia (Italy); Dziuk, Miroslaw; Tkaczewski, Konrad [Military Institute of Medicine, Warsaw (Poland); Ahond-Vionnet, Renee; Nodari, Guillaume [Hopital Pierre Beregovoy, Service de Medecine Nucleaire, Nevers (France); Todde, Sergio [University of Milan-Bicocca, Tecnomed Foundation, Monza (Italy)

    2018-01-15

    The aim of the present study was to evaluate the added diagnostic value of respiratory-gated 4D18F-FDG PET/CT in liver lesion detection and characterization in a European multicenter retrospective study. Fifty-six oncological patients (29 males and 27 females, mean age, 61.2 ± 11.2 years) from five European centers, submitted to standard 3D-PET/CT and liver 4D-PET/CT were retrospectively evaluated. Based on visual analysis, liver PET/CT findings were scored as positive, negative, or equivocal both in 3D and 4D PET/CT. The impact of 4D-PET/CT on the confidence in classifying liver lesions was assessed. PET/CT findings were compared to histology and clinical follow-up as standard reference and diagnostic accuracy was calculated for both techniques. At semi-quantitative analysis, SUVmax was calculated for each detected lesion in 3D and 4D-PET/CT. Overall, 72 liver lesions were considered for the analysis. Based on visual analysis in 3D-PET/CT, 32/72 (44.4%) lesions were considered positive, 21/72 (29.2%) negative, and 19/72 (26.4%) equivocal, while in 4D-PET/CT 48/72 (66.7%) lesions were defined positive, 23/72 (31.9%) negative, and 1/72 (1.4%) equivocal. 4D-PET/CT findings increased the confidence in lesion definition in 37/72 lesions (51.4%). Considering 3D equivocal lesions as positive, sensitivity, specificity, and accuracy were 88.9, 70.0, and 83.1%, respectively, while the same figures were 67.7, 90.0, and 73.8% if 3D equivocal findings were included as negative. 4D-PET/CT sensitivity, specificity, and accuracy were 97.8, 90.0, and 95.4%, respectively, considering equivocal lesions as positive and 95.6, 90.0, and 93.8% considering equivocal lesions as negative. The SUVmax of the liver lesions in 4D-PET (mean ± SD, 6.9 ± 3.2) was significantly higher (p < 0.001) than SUVmax in 3D-PET (mean ± SD, 5.2 ± 2.3). Respiratory-gated PET/CT technique is a valuable clinical tool in diagnosing liver lesions, reducing 3D undetermined findings, improving diagnostic

  18. Registration and Summation of Respiratory-Gated or Breath-Hold PET Images Based on Deformation Estimation of Lung from CT Image

    Directory of Open Access Journals (Sweden)

    Hideaki Haneishi

    2016-01-01

    Full Text Available Lung motion due to respiration causes image degradation in medical imaging, especially in nuclear medicine which requires long acquisition times. We have developed a method for image correction between the respiratory-gated (RG PET images in different respiration phases or breath-hold (BH PET images in an inconsistent respiration phase. In the method, the RG or BH-PET images in different respiration phases are deformed under two criteria: similarity of the image intensity distribution and smoothness of the estimated motion vector field (MVF. However, only these criteria may cause unnatural motion estimation of lung. In this paper, assuming the use of a PET-CT scanner, we add another criterion that is the similarity for the motion direction estimated from inhalation and exhalation CT images. The proposed method was first applied to a numerical phantom XCAT with tumors and then applied to BH-PET image data for seven patients. The resultant tumor contrasts and the estimated motion vector fields were compared with those obtained by our previous method. Through those experiments we confirmed that the proposed method can provide an improved and more stable image quality for both RG and BH-PET images.

  19. Delineation of the anatomical relationship of innominate artery and trachea by respiratory-gated MR imaging with true FISP sequence in patients with severe motor and intellectual disabilities

    International Nuclear Information System (INIS)

    Fujikawa, Yoshinao; Sato, Noriko; Sugai, Kenji; Endo, Yusaku; Matsufuji, Hiroki; Oomi, Tsuyoshi; Honzawa, Shiho; Sasaki, Masayuki

    2008-01-01

    Tracheoinnominate artery fistula is a well-known complication that arises on using a cannula. Therefore, routine examination of the anatomical relationship of the innominate artery and trachea should be carried out. We evaluated the usefulness of magnetic resonance imaging in 5 patients with severe motor and intellectual disabilities (SMID) using a combination of true-fast imaging of steady-state precession (true-FISP) sequences and two-dimensional prospective acquisition correction (2D-PACE). For all patients, the trachea and the innominate artery were identified without sedation and contrast media. In one patient, the innominate artery was observed to be pressing on the trachea. In three patients, the trachea and innominate artery were brought very close each other, and in the other patient the anatomical relationship of the trachea and surrounding structure was delineated before tracheotomy. The validity of true-FISP sequences combined with the respiratory-gated technique was confirmed useful for the patients who are difficult to lie quietly and to hold their breath voluntarily. (author)

  20. High-resolution imaging of pulmonary ventilation and perfusion with 68Ga-VQ respiratory gated (4-D) PET/CT

    International Nuclear Information System (INIS)

    Callahan, Jason; Hofman, Michael S.; Siva, Shankar; Kron, Tomas; Schneider, Michal E.; Binns, David; Eu, Peter; Hicks, Rodney J.

    2014-01-01

    Our group has previously reported on the use of 68 Ga-ventilation/perfusion (VQ) PET/CT scanning for the diagnosis of pulmonary embolism. We describe here the acquisition methodology for 68 Ga-VQ respiratory gated (4-D) PET/CT and the effects of respiratory motion on image coregistration in VQ scanning. A prospective study was performed in 15 patients with non-small-cell lung cancer. 4-D PET and 4-D CT images were acquired using an infrared marker on the patient's abdomen as a surrogate for breathing motion following inhalation of Galligas and intravenous administration of 68 Ga-macroaggregated albumin. Images were reconstructed with phase-matched attenuation correction. The lungs were contoured on CT and PET VQ images during free-breathing (FB) and at maximum inspiration (Insp) and expiration (Exp). The similarity between PET and CT volumes was measured using the Dice coefficient (DC) comparing the following groups; (1) FB-PET/CT, (2) InspPET/InspCT, (3) ExpPET/Exp CT, and (4) FB-PET/AveCT. A repeated measures one-way ANOVA with multiple comparison Tukey tests were performed to evaluate any difference between the groups. Diaphragmatic motion in the superior-inferior direction on the 4-D CT scan was also measured. 4-D VQ scanning was successful in all patients without additional acquisition time compared to the nongated technique. The highest volume overlap was between ExpPET and ExpCT and between FB-PET and AveCT with a DC of 0.82 and 0.80 for ventilation and perfusion, respectively. This was significantly better than the DC comparing the other groups (0.78-0.79, p 68 Ga-VQ 4-D PET/CT is feasible and the blurring caused by respiratory motion is well corrected with 4-D acquisition, which principally reduces artefact at the lung bases. The images with the highest spatial overlap were the combined expiration phase or FB PET and average CT. With higher resolution than SPECT/CT, the PET/CT technique has a broad range of potential clinical applications including

  1. Impact of window size of extracranial stereotactic treatments Gating with respiratory synchronization; Analisis de las correcciones interfraccion en el posicionamiento de los pacientes mediante IGRT

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Rubio, P.; Castro Tejero, P.; Medrano Prado, J. C.

    2011-07-01

    The choice of the gating window is to find a compromise between the duration of the treatment session and the accuracy and precision in the administration. This paper analyzes the dosimetric impact depending on the selected gating window.

  2. Hypofractionated Breast Radiation: Shorter Scheme, Lower Toxicity.

    Science.gov (United States)

    Linares, Isabel; Tovar, María Isabel; Zurita, Mercedes; Guerrero, Rosario; Expósito, Manuela; Del Moral, Rosario

    2016-08-01

    We analyzed the toxicity and cosmetic outcomes for patients who had undergone 3-dimensional conformal radiotherapy with a hypofractionated schedule and identified the risk factors associated with such a schedule. A total of 143 patients were treated for breast cancer (stage 0-III) with a hypofractionated radiation schedule after breast-conserving surgery from 2006 to 2011. Most patients received 42.4 Gy in 16 daily fractions, 2.65 Gy per fraction to the whole breast plus an additional simultaneous integrated or sequential boost to the tumor bed. The median follow-up period was 36 months. Mild acute skin toxicity was observed in 62%; 7% of the patients developed moderate skin toxicity, but no grade 4 toxicity was observed. The prevalence of fibrosis within the boost area was 5%, but no grade ≥ 2 was observed. The prevalence of fibrosis of any grade was greater in the nonboost (23%) than in the boost area. Of all the patients, 91% had good or excellent cosmetic outcomes. From the multivariate analysis, the incidence of epithelitis correlated with the patient's treated volume (P = .044). The incidence of acute toxicity correlated with the boost type to the tumor bed and the total treatment dose (P = .012 and P = .002, respectively). Also, a poor to fair cosmetic outcome was significantly associated statistically with the surgery type (P = .05), boost type (P = .004), and total dose (P = .001). Delivering whole-breast irradiation with a hypofractionated schedule of 42.4 Gy plus a simultaneous integrated boost to the tumor bed appears to be a safe and effective technique, with good cosmetic results and lower toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Kawasaki disease-associated coronary artery lesions with navigator echo-based. Respiratory-gated three dimensional coronary magnetic resonance angiography compared with echocardiography in young children

    International Nuclear Information System (INIS)

    Amino, Masayuki; Teraoka, Kunihiko; Hirano, Masaharu; Kawashima, Naoshi; Kakizaki, Dai; Ookubo, Yasuo; Sasaki, Kazuyoshi; Katuyama, Hiroaki

    2004-01-01

    Navigator echo-based respiratory-gated three dimensional coronary magnetic resonance angiography (3D-CMRA) was compared with echocardiography, to determine whether 3D-CMRA was useful for the evaluation of Kawasaki disease-associated coronary artery lesions. Sixteen consecutive patients (imaging was performed 17 times in total) who were given a diagnosis of Kawasaki's disease at the pediatric department of our hospital and examined for the precise examination of complicating coronary artery lesions on MRI using a navigator-echo technique because of their incapability of holding their breath during imaging were entered into the present study. A 1.5T MRI system was used. Gd-DOTA was given at a total volume of 0.1 mmol/kg. During imaging, CMRA visualized the left coronary arteries in all 17 cases and the right coronary arteries in 16 cases, but not in one case. The left main coronary trunk segment no.5 was demonstrated in all cases with CMRA, but not in 4 cases with echocardiography. The left anterior descending branch no.6 was visualized in 11 of the 17 cases with CMRA, but only in 5 cases with echocardiography. The left circumflex branch no.11 was observed in 6 cases with CMRA, but only in 2 cases with echocardiography. As for the right coronary arteries, branches no.1 and no.2 were observed in 16 and 9 cases with CMRA, respectively, and in 13 and 3 cases with echocardiography, respectively. Vascular diameters measured on CMRA were almost identical to those on echocardiography, within the range of arteries visualized. 3D-CMRA combined with a navigator echo technique appears to be a useful tool for the observation of coronary artery lesions associated with Kawasaki's disease because it is superior in lesion visualization to echocardiography. (author)

  4. Evaluation of a New Motion-correction Algorithm Using On-rigid Registration in Respiratory-gated PET/CT Images of Liver Tumors.

    Science.gov (United States)

    Wagatsuma, Kei; Osawa, Tatsufumi; Yokokawa, Naoki; Miwa, Kenta; Oda, Keiichi; Kudo, Yoshiro; Unno, Yasushi; Ito, Kimiteru; Ishii, Kenji

    2016-01-01

    The present study aimed to determine the qualitative and quantitative accuracy of the Q.Freeze algorithm in PET/CT images of liver tumors. A body phantom and hot spheres representing liver tumors contained 5.3 and 21.2 kBq/mL of a solution containing 18 F radioactivity, respectively. The phantoms were moved in the superior-inferior direction at a motion displacement of 20 mm. Conventional respiratory-gated (RG) and Q.Freeze images were sorted into 6, 10, and 13 phase-groups. The SUV ave was calculated from the background of the body phantom, and the SUV max was determined from the hot spheres of the liver tumors. Three patients with four liver tumors were also clinically assessed by whole-body and RG PET. The RG and Q.Freeze images derived from the clinical study were also sorted into 6, 10 and 13 phase-groups. Liver signal-to-noise ratio (SNR) and SUV max were determined from the RG and Q.Freeze clinical images. The SUV ave of Q.Freeze images was the same as those derived from the body phantom using RG. The liver SNR improved with Q.Freeze, and the SUVs max was not overestimated when Q.Freeze was applied in both the phantom and clinical studies. Q.Freeze did not degrade the liver SNR and SUV max even though the phase number was larger. Q.Freeze delivered qualitative and quantitative motion correction than conventional RG imaging even in 10-phase groups.

  5. High-resolution imaging of pulmonary ventilation and perfusion with {sup 68}Ga-VQ respiratory gated (4-D) PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, Jason [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne, VIC (Australia); Hofman, Michael S. [The University of Melbourne, Department of Medicine, Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne, VIC (Australia); Siva, Shankar [The University of Melbourne, Peter MacCallum Cancer Centre, Department of Radiation Oncology, East Melbourne, VIC (Australia); The University of Melbourne, Sir Peter MacCallum Department of Oncology, East Melbourne, VIC (Australia); Kron, Tomas [The University of Melbourne, Sir Peter MacCallum Department of Oncology, East Melbourne, VIC (Australia); The University of Melbourne, Peter MacCallum Cancer Centre, Department of Physical Sciences, East Melbourne, VIC (Australia); Schneider, Michal E. [Monash University, Department of Medical Imaging and Radiation Science, Clayton, VIC (Australia); Binns, David; Eu, Peter [Peter MacCallum Cancer Centre, Centre for Cancer Imaging, East Melbourne, VIC (Australia); Hicks, Rodney J. [The University of Melbourne, Sir Peter MacCallum Department of Oncology, Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne, VIC (Australia)

    2014-02-15

    Our group has previously reported on the use of {sup 68}Ga-ventilation/perfusion (VQ) PET/CT scanning for the diagnosis of pulmonary embolism. We describe here the acquisition methodology for {sup 68}Ga-VQ respiratory gated (4-D) PET/CT and the effects of respiratory motion on image coregistration in VQ scanning. A prospective study was performed in 15 patients with non-small-cell lung cancer. 4-D PET and 4-D CT images were acquired using an infrared marker on the patient's abdomen as a surrogate for breathing motion following inhalation of Galligas and intravenous administration of {sup 68}Ga-macroaggregated albumin. Images were reconstructed with phase-matched attenuation correction. The lungs were contoured on CT and PET VQ images during free-breathing (FB) and at maximum inspiration (Insp) and expiration (Exp). The similarity between PET and CT volumes was measured using the Dice coefficient (DC) comparing the following groups; (1) FB-PET/CT, (2) InspPET/InspCT, (3) ExpPET/Exp CT, and (4) FB-PET/AveCT. A repeated measures one-way ANOVA with multiple comparison Tukey tests were performed to evaluate any difference between the groups. Diaphragmatic motion in the superior-inferior direction on the 4-D CT scan was also measured. 4-D VQ scanning was successful in all patients without additional acquisition time compared to the nongated technique. The highest volume overlap was between ExpPET and ExpCT and between FB-PET and AveCT with a DC of 0.82 and 0.80 for ventilation and perfusion, respectively. This was significantly better than the DC comparing the other groups (0.78-0.79, p < 0.05). These values agreed with a visual inspection of the images with improved image coregistration around the lung bases. The diaphragmatic motion during the 4-D CT scan was highly variable with a range of 0.4-3.4 cm (SD 0.81 cm) in the right lung and 0-2.8 cm (SD 0.83 cm) in the left lung. Right-sided diaphragmatic nerve palsy was observed in 3 of 15 patients. {sup 68}Ga-VQ 4-D

  6. Individualized planning target volumes for intrafraction motion during hypofractionated intensity-modulated radiotherapy boost for prostate cancer

    International Nuclear Information System (INIS)

    Cheung, Patrick; Sixel, Katharina; Morton, Gerard; Loblaw, D. Andrew; Tirona, Romeo; Pang, Geordi; Choo, Richard; Szumacher, Ewa; DeBoer, Gerrit; Pignol, Jean-Philippe

    2005-01-01

    Purpose: The objective of the study was to access toxicities of delivering a hypofractionated intensity-modulated radiotherapy (IMRT) boost with individualized intrafraction planning target volume (PTV) margins and daily online correction for prostate position. Methods and materials: Phase I involved delivering 42 Gy in 21 fractions using three-dimensional conformal radiotherapy, followed by a Phase II IMRT boost of 30 Gy in 10 fractions. Digital fluoroscopy was used to measure respiratory-induced motion of implanted fiducial markers within the prostate. Electronic portal images were taken of fiducial marker positions before and after each fraction of radiotherapy during the first 9 days of treatment to calculate intrafraction motion. A uniform 10-mm PTV margin was used for the first phase of treatment. PTV margins for Phase II were patient-specific and were calculated from the respiratory and intrafraction motion data obtained from Phase I. The IMRT boost was delivered with daily online correction of fiducial marker position. Acute toxicity was measured using National Cancer Institute Common Toxicity Criteria, version 2.0. Results: In 33 patients who had completed treatment, the average PTV margin used during the hypofractionated IMRT boost was 3 mm in the lateral direction, 3 mm in the superior-inferior direction, and 4 mm in the anteroposterior direction. No patients developed acute Grade 3 rectal toxicity. Three patients developed acute Grade 3 urinary frequency and urgency. Conclusions: PTV margins can be reduced significantly with daily online correction of prostate position. Delivering a hypofractionated boost with this high-precision IMRT technique resulted in acceptable acute toxicity

  7. Hypofractionated stereotactic radiotherapy for malignant tumors of the lung

    Directory of Open Access Journals (Sweden)

    О. Ю. Аникеева

    2015-10-01

    Full Text Available Hypofractionated stereotactic radiotherapy was used for 26 patients at medically inoperable stage I of non-small cell lung cancer with dose escalation of 48-54 Gy prescribed at 90 or 95% isodose level in 3-4 fractions. Nine-months local control and cancer-specific survival were 82.0 and 66.8% respectively, with minimal toxicity. For metastatic lung tumors local control was obtained in 92% cases. Hypofractionated stereotactic radiation therapy (SBRT is safe and feasible for the treatment of inoperable primary lung cancer and single lung metastasis.

  8. Comparative evaluation of CT-based and respiratory-gated PET/CT-based planning target volume (PTV) in the definition of radiation treatment planning in lung cancer: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, Luca; Elisei, Federica [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); Meregalli, Sofia; Niespolo, Rita [San Gerardo Hospital, Radiotherapy, Monza (Italy); Zorz, Alessandra; De Ponti, Elena; Morzenti, Sabrina; Crespi, Andrea [San Gerardo Hospital, Medical Physics, Monza (Italy); Brenna, Sarah [University of Milan-Bicocca, School of Radiation Oncology, Monza (Italy); Gardani, Gianstefano [San Gerardo Hospital, Radiotherapy, Monza (Italy); University of Milan-Bicocca, Milan (Italy); Messa, Cristina [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); University of Milan-Bicocca, Tecnomed Foundation, Milan (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy)

    2014-04-15

    The aim of this study was to compare planning target volume (PTV) defined on respiratory-gated positron emission tomography (PET)/CT (RG-PET/CT) to PTV based on ungated free-breathing CT and to evaluate if RG-PET/CT can be useful to personalize PTV by tailoring the target volume to the lesion motion in lung cancer patients. Thirteen lung cancer patients (six men, mean age 70.0 years, 1 small cell lung cancer, 12 non-small cell lung cancer) who were candidates for radiation therapy were prospectively enrolled and submitted to RG-PET/CT. Ungated free-breathing CT images obtained during a PET/CT study were visually contoured by the radiation oncologist to define standard clinical target volumes (CTV1). Standard PTV (PTV1) resulted from CTV1 with the addition of 1-cm expansion of margins in all directions. RG-PET/CT images were contoured by the nuclear medicine physician and radiation oncologist according to a standardized institutional protocol for contouring gated images. Each CT and PET image of the patient's respiratory cycle phases was contoured to obtain the RG-CT-based CTV (CTV2) and the RG-PET/CT-based CTV (CTV3), respectively. RG-CT-based and RG-PET/CT-based PTV (PTV2 and PTV3, respectively) were then derived from gated CTVs with a margin expansion of 7-8 mm in head to feet direction and 5 mm in anterior to posterior and left to right direction. The portions of gated PTV2 and PTV3 geometrically not encompassed in PTV1 (PTV2 out PTV1 and PTV3 out PTV1) were also calculated. Mean ± SD CTV1, CTV2 and CTV3 were 30.5 ± 33.2, 43.1 ± 43.2 and 44.8 ± 45.2 ml, respectively. CTV1 was significantly smaller than CTV2 and CTV3 (p = 0.017 and 0.009 with Student's t test, respectively). No significant difference was found between CTV2 and CTV3. Mean ± SD of PTV1, PTV2 and PTV3 were 118.7 ± 94.1, 93.8 ± 80.2 and 97.0 ± 83.9 ml, respectively. PTV1 was significantly larger than PTV2 and PTV3 (p = 0.038 and 0.043 with Student's t test, respectively). No

  9. The impact of optimal respiratory gating and image noise on evaluation of intra-tumor heterogeneity in 18F-FDG positron emission tomography imaging of lung cancer

    NARCIS (Netherlands)

    Grootjans, W.; Tixier, F.; Vos, C.S. van der; Vriens, D.; Rest, C.C. Le; Bussink, J.; Oyen, W.J.G.; Geus-Oei, L.F. de; Visvikis, D.; Visser, E.P.

    2016-01-01

    Assessment of measurement accuracy of intra-tumor heterogeneity using texture features in positron emission tomography (PET) images is essential to characterize cancer lesions with high precision. In this study, we investigated the influence of respiratory motion and varying noise levels on

  10. The Impact of Optimal Respiratory Gating and Image Noise on Evaluation of Intratumor Heterogeneity on 18F-FDG PET Imaging of Lung Cancer

    NARCIS (Netherlands)

    Grootjans, W.; Tixier, F.; van der Vos, Charlotte Sophie; Vriens, D.; Le Rest, C.C.; Bussink, J.; Oyen, W.J.; de Geus-Oei, Lioe-Fee; Visvikis, D.; Visser, E.P.

    2016-01-01

    Accurate measurement of intratumor heterogeneity using parameters of texture on PET images is essential for precise characterization of cancer lesions. In this study, we investigated the influence of respiratory motion and varying noise levels on quantification of textural parameters in patients

  11. Hypofractionated regional nodal irradiation for breast cancer: Examining the data and potential for future studies

    International Nuclear Information System (INIS)

    Badiyan, Shahed N.; Shah, Chirag; Arthur, Douglas; Khan, Atif J.; Freedman, Gary; Poppe, Matthew M.; Vicini, Frank A.

    2014-01-01

    Limited data are available examining the role of hypofractionated radiation schedules in the management of women requiring regional nodal irradiation (RNI). The purpose of this review is to examine the available literature for the efficacy (where available) and toxicity of hypofractionated radiation schedules in breast cancer with RNI limited to the axilla and supraclavicular regions. Multiple randomized and prospective studies have documented the safety and efficacy of hypofractionated schedules delivering whole breast irradiation (WBI) alone. Subsets from these randomized trials and smaller prospective/single-institution studies have documented the feasibility of hypofractionated RNI but the limited numbers prevent definitive conclusions and limited efficacy data are available. With regard to possible toxicity affecting organs at risk with RNI, key structures include the breast, skin, heart, lungs, axilla (lymphedema), and brachial plexus. Based on data from several randomized trials, hypofractionated radiation is not associated with significant changes in breast toxicity/cosmesis or cardiac toxicity; the addition of hypofractionated RNI would not be expected to change the rates of breast or cardiac toxicity. While RNI has been shown to increase rates of pulmonary toxicity, hypofractionated RNI has not been associated with more frequent pulmonary complications than standard RNI. Moving forward, future studies will have to evaluate for increased lung toxicity. With regard to lymphedema, data from randomized hypofractionated WBI trials failed to demonstrate an increase in lymphedema and smaller studies utilizing hypofractionated RNI have failed to as well. Data from head and neck cancer as well as hypofractionated breast radiation with RNI have failed to demonstrate an increase in brachial plexopathy with the exception of older trials that used much larger dose per fraction (>4 Gy/fraction) schedules. At this time, published data support the feasibility of

  12. Mild Lung Restriction in Breast Cancer Patients After Hypofractionated and Conventional Radiation Therapy: A 3-Year Follow-Up

    International Nuclear Information System (INIS)

    Verbanck, Sylvia; Hanon, Shane; Schuermans, Daniel; Van Parijs, Hilde; Vinh-Hung, Vincent; Miedema, Geertje; Verellen, Dirk; Storme, Guy; Fontaine, Christel; Lamote, Jan; De Ridder, Mark; Vincken, Walter

    2016-01-01

    Purpose: To assess the effect of radiation therapy on lung function over the course of 3 years. Methods and Materials: Evolution of restrictive and obstructive lung function parameters was investigated in 108 breast cancer participants in a randomized, controlled trial comparing conventional radiation therapy (CR) and hypofractionated tomotherapy (TT) (age at inclusion ranging 32-81 years). Spirometry, plethysmography, and hemoglobin-corrected diffusing capacity were assessed at baseline and after 3 months and 1, 2, and 3 years. Natural aging was accounted for by considering all lung function parameters in terms of percent predicted values using the most recent reference values for women aged up to 80 years. Results: In the patients with negligible history of respiratory disease or smoking (n=77), the greatest rate of functional decline was observed during the initial 3 months, this acute decrease being more marked in the CR versus the TT arm. During the remainder of the 3-year follow-up period, values (in terms of percent predicted) were maintained (diffusing capacity) or continued to decline at a slower rate (forced vital capacity). However, the average decline of the restrictive lung function parameters over a 3-year period did not exceed 9% predicted in either the TT or the CR arm. Obstructive lung function parameters remained unaffected throughout. Including also the 31 patients with a history of respiratory disease or more than 10 pack-years showed a very similar restrictive pattern. Conclusions: In women with breast cancer, both conventional radiation therapy and hypofractionated tomotherapy induce small but consistent restrictive lung patterns over the course of a 3-year period, irrespective of baseline respiratory status or smoking history. The fastest rate of lung function decline generally occurred in the first 3 months.

  13. Mild Lung Restriction in Breast Cancer Patients After Hypofractionated and Conventional Radiation Therapy: A 3-Year Follow-Up

    Energy Technology Data Exchange (ETDEWEB)

    Verbanck, Sylvia, E-mail: sylvia.verbanck@uzbrussel.be [Respiratory Division, University Hospital UZ Brussel, Brussels (Belgium); Hanon, Shane; Schuermans, Daniel [Respiratory Division, University Hospital UZ Brussel, Brussels (Belgium); Van Parijs, Hilde; Vinh-Hung, Vincent; Miedema, Geertje; Verellen, Dirk; Storme, Guy [Department of Radiotherapy, University Hospital UZ Brussel, Brussels (Belgium); Fontaine, Christel; Lamote, Jan [Department of Senology and Oncologic Surgery, University Hospital UZ Brussel, Brussels (Belgium); De Ridder, Mark [Department of Radiotherapy, University Hospital UZ Brussel, Brussels (Belgium); Vincken, Walter [Respiratory Division, University Hospital UZ Brussel, Brussels (Belgium)

    2016-07-01

    Purpose: To assess the effect of radiation therapy on lung function over the course of 3 years. Methods and Materials: Evolution of restrictive and obstructive lung function parameters was investigated in 108 breast cancer participants in a randomized, controlled trial comparing conventional radiation therapy (CR) and hypofractionated tomotherapy (TT) (age at inclusion ranging 32-81 years). Spirometry, plethysmography, and hemoglobin-corrected diffusing capacity were assessed at baseline and after 3 months and 1, 2, and 3 years. Natural aging was accounted for by considering all lung function parameters in terms of percent predicted values using the most recent reference values for women aged up to 80 years. Results: In the patients with negligible history of respiratory disease or smoking (n=77), the greatest rate of functional decline was observed during the initial 3 months, this acute decrease being more marked in the CR versus the TT arm. During the remainder of the 3-year follow-up period, values (in terms of percent predicted) were maintained (diffusing capacity) or continued to decline at a slower rate (forced vital capacity). However, the average decline of the restrictive lung function parameters over a 3-year period did not exceed 9% predicted in either the TT or the CR arm. Obstructive lung function parameters remained unaffected throughout. Including also the 31 patients with a history of respiratory disease or more than 10 pack-years showed a very similar restrictive pattern. Conclusions: In women with breast cancer, both conventional radiation therapy and hypofractionated tomotherapy induce small but consistent restrictive lung patterns over the course of a 3-year period, irrespective of baseline respiratory status or smoking history. The fastest rate of lung function decline generally occurred in the first 3 months.

  14. Hypofractionated Adjuvant Whole Breast Radiotherapy: Progress and Prospects

    International Nuclear Information System (INIS)

    Yarnold, John; Haviland, Joanne

    2010-01-01

    Published results of randomised trials involving >7000 women confirm the safety and efficacy of hypofractionated schedules of adjuvant radiotherapy for women with early breast cancer using fraction sizes between 2 and 3 Gy assuming appropriate downward adjustments to total dose. Unnecessary concerns relating to heart tolerance, suboptimal dose distribution and duration of follow up need not discourage the routine adoption of 15- or 16-fraction schedules in women treated by breast conservation surgery for early breast cancer. Regardless of fractionation regimen, dose escalation to the index quadrant in high risk subgroups will result in a greater relative increase in late adverse effects than tumour control, a therapeutic disadvantage that can only be overcome by exploiting a marked dose-volume effect. A 15-fraction schedule of whole breast radiotherapy is unlikely to represent the lower limits of hypofractionation, and the preliminary results of a 5-fraction regimen are encouraging

  15. Adaptive hypofractionated gamma knife radiosurgery for a large brainstem metastasis

    DEFF Research Database (Denmark)

    Sinclair, Georges; Bartek, Jiri; Martin, Heather

    2016-01-01

    cancer in July 2011, initially treated with chemotherapy and tyrosine kinase inhibitors, developed multiple brain metastases March 2013, with subsequent whole brain radiotherapy, after which a magnetic resonance imaging (MRI) showed a significant volume regression of all brain metastases. A follow-up MRI...... adaptive hypofractionation proved to be effective to achieve tumor control while limiting local adverse reactions. This surgical modality should be considered when managing larger brain lesions in critical areas....

  16. Adjuvant radiotherapy for cutaneous melanoma: Comparing hypofractionation to conventional fractionation

    International Nuclear Information System (INIS)

    Chang, Daniel T.; Amdur, Robert J.; Morris, Christopher G. M.S.; Mendenhall, William M.

    2006-01-01

    Purpose: To examine locoregional control after adjuvant radiotherapy (RT) for cutaneous melanoma and compare outcomes between conventional fractionation and hypofractionation. Methods and Materials: Between January 1980 and June 2004, 56 patients with high-risk disease were treated with adjuvant RT. Indications for RT included: recurrent disease, cervical lymph node involvement, lymph nodes >3 cm, more than three lymph nodes involved, extracapsular extension, gross residual disease, close or positive margins, or satellitosis. Hypofractionation was used in 41 patients (73%) and conventional fractionation was used in 15 patients (27%). Results: The median age was 61 years (21->90). The median follow-up among living patients was 4.4 years (range, 0.6-14.4 years). The primary site was located in the head and neck in 49 patients (87%) and below the clavicles in 7 patients (13%). There were 7 in-field locoregional failures (12%), 3 out-of-field regional failures (5%), and 24 (43%) distant failures. The 5-year in-field locoregional control (ifLRC) and freedom from distant metastases (FFDM) rates were 87% and 43%, respectively. The 5-year cause-specific (CSS) and overall survival (OS) was 57% and 46%, respectively. The only factor associated with ifLRC was satellitosis (p = 0.0002). Nodal involvement was the only factor associated with FFDM (p = 0.0007), CSS (p = 0.0065), and OS (p = 0.016). Two patients (4%) who experienced severe late complications, osteoradionecrosis of the temporal bone and radiation plexopathy, and both received hypofractionation (5%). Conclusions: Although surgery and adjuvant RT provides excellent locoregional control, distant metastases remain the major cause of mortality. Hypofractionation and conventional fractionation are equally efficacious

  17. Linear gate

    International Nuclear Information System (INIS)

    Suwono.

    1978-01-01

    A linear gate providing a variable gate duration from 0,40μsec to 4μsec was developed. The electronic circuity consists of a linear circuit and an enable circuit. The input signal can be either unipolar or bipolar. If the input signal is bipolar, the negative portion will be filtered. The operation of the linear gate is controlled by the application of a positive enable pulse. (author)

  18. Extreme Hypofractionated Image-Guided Radiotherapy for Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Carlo Greco

    2013-09-01

    Full Text Available An emerging body of data suggests that hypofractionated radiation schedules, where a higher dose per fraction is delivered in a smaller number of sessions, may be superior to conventional fractionation schemes in terms of both tumour control and toxicity profile in the management of adenocarcinoma of the prostate. However, the optimal hypofractionation scheme is still the subject of scientific debate. Modern computer-driven technology enables the safe implementation of extreme hypo fractionation (often referred to as stereotactic body radiation therapy [SBRT]. Several studies are currently being conducted to clarify the yet unresolved issues regarding treatment techniques and fractionation regimens. Recently, the American Society for Radiation Oncology (ASTRO issued a model policy indicating that data supporting the use of SBRT for prostate cancer have matured to a point where SBRT could be considered an appropriate alternative for select patients with low-to-intermediate risk disease. The present article reviews some of the currently available data and examines the impact of tracking technology to mitigate intra-fraction target motion, thus, potentially further improving the clinical outcomes of extreme hypofractionated radiation therapy in appropriately selected prostate cancer patients. The Champalimaud Centre for the Unknown (CCU’s currently ongoing Phase I feasibility study is described; it delivers 45 Gy in five fractions using prostate fixation via a rectal balloon, and urethral sparing via catheter placement with on-line intra-fractional motion tracking through beacon transponder technology.

  19. Hypofractionation does not increase radiation pneumonitis risk with modern conformal radiation delivery techniques

    DEFF Research Database (Denmark)

    Vogelius, Ivan R; Westerly, David C; Cannon, George M

    2010-01-01

    To study the interaction between radiation dose distribution and hypofractionated radiotherapy with respect to the risk of radiation pneumonitis (RP) estimated from normal tissue complication probability (NTCP) models.......To study the interaction between radiation dose distribution and hypofractionated radiotherapy with respect to the risk of radiation pneumonitis (RP) estimated from normal tissue complication probability (NTCP) models....

  20. Adoption of Hypofractionated Whole-Breast Irradiation for Early-Stage Breast Cancer: A National Cancer Data Base Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Elyn H. [Yale School of Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Mougalian, Sarah S. [Yale School of Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Department of Medical Oncology, Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Soulos, Pamela R. [Yale School of Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Rutter, Charles E.; Evans, Suzanne B. [Yale School of Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut (United States); Haffty, Bruce G. [Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey and Robert Wood Johnson Medical School, New Brunswick, New Jersey (United States); Gross, Cary P. [Yale School of Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey and Robert Wood Johnson Medical School, New Brunswick, New Jersey (United States); Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Yu, James B., E-mail: james.b.yu@yale.edu [Yale School of Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut (United States)

    2014-12-01

    Purpose: To evaluate the relationship of patient, hospital, and cancer characteristics with the adoption of hypofractionation in a national sample of patients diagnosed with early-stage breast cancer. Methods and Materials: We performed a retrospective study of breast cancer patients in the National Cancer Data Base from 2004-2011 who were treated with radiation therapy and met eligibility criteria for hypofractionation. We used logistic regression to identify factors associated with receipt of hypofractionation (vs conventional fractionation). Results: We identified 13,271 women (11.7%) and 99,996 women (88.3%) with early-stage breast cancer who were treated with hypofractionation and conventional fractionation, respectively. The use of hypofractionation increased significantly, with 5.4% of patients receiving it in 2004 compared with 22.8% in 2011 (P<.001 for trend). Patients living ≥50 miles from the cancer reporting facility had increased odds of receiving hypofractionation (odds ratio 1.57 [95% confidence interval 1.44-1.72], P<.001). Adoption of hypofractionation was associated with treatment at an academic center (P<.001) and living in an area with high median income (P<.001). Hypofractionation was less likely to be used in patients with high-risk disease, such as increased tumor size (P<.001) or poorly differentiated histologic grade (P<.001). Conclusions: The use of hypofractionation is rising and is associated with increased travel distance and treatment at an academic center. Further adoption of hypofractionation may be tempered by both clinical and nonclinical concerns.

  1. Adoption of Hypofractionated Whole-Breast Irradiation for Early-Stage Breast Cancer: A National Cancer Data Base Analysis

    International Nuclear Information System (INIS)

    Wang, Elyn H.; Mougalian, Sarah S.; Soulos, Pamela R.; Rutter, Charles E.; Evans, Suzanne B.; Haffty, Bruce G.; Gross, Cary P.; Yu, James B.

    2014-01-01

    Purpose: To evaluate the relationship of patient, hospital, and cancer characteristics with the adoption of hypofractionation in a national sample of patients diagnosed with early-stage breast cancer. Methods and Materials: We performed a retrospective study of breast cancer patients in the National Cancer Data Base from 2004-2011 who were treated with radiation therapy and met eligibility criteria for hypofractionation. We used logistic regression to identify factors associated with receipt of hypofractionation (vs conventional fractionation). Results: We identified 13,271 women (11.7%) and 99,996 women (88.3%) with early-stage breast cancer who were treated with hypofractionation and conventional fractionation, respectively. The use of hypofractionation increased significantly, with 5.4% of patients receiving it in 2004 compared with 22.8% in 2011 (P<.001 for trend). Patients living ≥50 miles from the cancer reporting facility had increased odds of receiving hypofractionation (odds ratio 1.57 [95% confidence interval 1.44-1.72], P<.001). Adoption of hypofractionation was associated with treatment at an academic center (P<.001) and living in an area with high median income (P<.001). Hypofractionation was less likely to be used in patients with high-risk disease, such as increased tumor size (P<.001) or poorly differentiated histologic grade (P<.001). Conclusions: The use of hypofractionation is rising and is associated with increased travel distance and treatment at an academic center. Further adoption of hypofractionation may be tempered by both clinical and nonclinical concerns

  2. Retrospective study of canine nasal tumor treated with hypofractionated radiotherapy

    International Nuclear Information System (INIS)

    Maruo, Takuya; Shida, Takuo; Fukuyama, Yasuhiro; Hosaka, Soshi; Noda, Masashi; Ito, Tetsuro; Sugiyama, Hiroki; Ishikawa, Takeshi; Madarame, Hiroo

    2011-01-01

    The object of this study was to evaluate hypofractionated multiportal field and two-portion (rostral and caudal portions divided by the eyelid) radiation therapy for canine nasal tumors. Sixty-three dogs underwent multiportal hypofractionated radiation therapy. The radiation field was divided into rostral and caudal portions by the eyelid. Treatments were performed four times for 57 dogs. The median irradiation dose/fraction was 8 Gy (range, 5-10 Gy); the median total dose was 32 Gy (10-40 Gy). Improvement of clinical symptoms was achieved in 53 (84.1%) of 63 cases. Median survival time was 197 days (range, 2-1,080 days). Median survival times with and without destruction of the cribriform plate before radiotherapy were 163 and 219 days, respectively. There was no significant difference between them. No other factors were related to survival according to a univariate analysis. All radiation side effects, except one, were grade I according to the VRTOG classification. It was not necessary to treat any dogs for skin side effects. One dog (1.6%) developed an oronasal fistula 1 year after completion of radiation therapy. This radiation protocol may be useful in reducing radiation side effects in dogs with cribriform plate destruction. (author)

  3. Hypofractionated stereotactic radiation therapy for recurrent glioblastoma: single institutional experience

    International Nuclear Information System (INIS)

    Ciammella, Patrizia; Podgornii, Ala; Galeandro, Maria; D’Abbiero, Nunziata; Pisanello, Anna; Botti, Andrea; Cagni, Elisabetta; Iori, Mauro; Iotti, Cinzia

    2013-01-01

    Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Tumor control and survival have improved with the use of radiotherapy (RT) plus concomitant and adjuvant chemotherapy, but the prognosis remain poor. In most cases the recurrence occurs within 7–9 months after primary treatment. Currently, many approaches are available for the salvage treatment of patients with recurrent GBM, including resection, re-irradiation or systemic agents, but no standard of care exists. We analysed a cohort of patients with recurrent GBM treated with frame-less hypofractionated stereotactic radiation therapy with a total dose of 25 Gy in 5 fractions. Of 91 consecutive patients with newly diagnosed GBM treated between 2007 and 2012 with conventional adjuvant chemo-radiation therapy, 15 underwent salvage RT at recurrence. The median time interval between primary RT and salvage RT was 10.8 months (range, 6–54 months). Overall, patients undergoing salvage RT showed a longer survival, with a median survival of 33 vs. 9.9 months (p= 0.00149). Median overall survival (OS) from salvage RT was 9.5 months. No patients demonstrated clinically significant acute morbidity, and all patients were able to complete the prescribed radiation therapy without interruption. Our results suggest that hypofractionated stereotactic radiation therapy is effective and safe in recurrent GBM. However, until prospective randomized trials will confirm these results, the decision for salvage treatment should remain individual and based on a multidisciplinary evaluation of each patient

  4. Respiratory acidosis

    Science.gov (United States)

    Ventilatory failure; Respiratory failure; Acidosis - respiratory ... Causes of respiratory acidosis include: Diseases of the airways (such as asthma and COPD ) Diseases of the lung tissue (such as ...

  5. Dual-gated cardiac PET-clinical feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Teraes, Mika; Kokki, Tommi; Noponen, Tommi; Hoppela, Erika; Sipilae, Hannu T.; Knuuti, Juhani [Turku PET Centre, PO BOX 52, Turku (Finland); Durand-Schaefer, Nicolas [General Electric Medical Systems, Buc (France); Pietilae, Mikko [Turku University Hospital, Department of Internal Medicine, Turku (Finland); Kiss, Jan [Turku University Hospital, Department of Surgery, Turku (Finland)

    2010-03-15

    Both respiratory and cardiac motions reduce image quality in myocardial imaging. For accurate imaging of small structures such as vulnerable coronary plaques, simultaneous cardiac and respiratory gating is warranted. This study tests the feasibility of a recently developed robust method for cardiac-respiratory gating. List-mode data with triggers from respiratory and cardiac cycles are rearranged into dual-gated segments and reconstructed with standard algorithms of a commercial PET/CT scanner. Cardiac gates were defined as three fixed phases and one variable diastolic phase. Chest motion was measured with a respiratory gating device and post-processed to determine gates. Preservation of quantification in dual-gated images was tested with an IEC whole-body phantom. Minipig and human studies were performed to evaluate the feasibility of the method. In minipig studies, a coronary catheter with radioactive tip was guided in coronary artery for in vivo and ex vivo acquisitions. Dual gating in humans with suspected cardiac disorders was performed using 18-F-FDG as a tracer. The method was found feasible for in vivo imaging and the radioactive catheter tip was better resolved in gated images. In human studies, the dual gating was found feasible and easy for clinical routine. Maximal movement of myocardial surface in cranio-caudal direction was over 20 mm. The shape of myocardium was clearly different between the gates and papillary muscles become more visible in diastolic images. The first clinical experiences using robust cardiac-respiratory dual gating are encouraging. Further testing in larger clinical populations using tracers designed especially for plaque imaging is warranted. (orig.)

  6. Dual-gated cardiac PET-clinical feasibility study

    International Nuclear Information System (INIS)

    Teraes, Mika; Kokki, Tommi; Noponen, Tommi; Hoppela, Erika; Sipilae, Hannu T.; Knuuti, Juhani; Durand-Schaefer, Nicolas; Pietilae, Mikko; Kiss, Jan

    2010-01-01

    Both respiratory and cardiac motions reduce image quality in myocardial imaging. For accurate imaging of small structures such as vulnerable coronary plaques, simultaneous cardiac and respiratory gating is warranted. This study tests the feasibility of a recently developed robust method for cardiac-respiratory gating. List-mode data with triggers from respiratory and cardiac cycles are rearranged into dual-gated segments and reconstructed with standard algorithms of a commercial PET/CT scanner. Cardiac gates were defined as three fixed phases and one variable diastolic phase. Chest motion was measured with a respiratory gating device and post-processed to determine gates. Preservation of quantification in dual-gated images was tested with an IEC whole-body phantom. Minipig and human studies were performed to evaluate the feasibility of the method. In minipig studies, a coronary catheter with radioactive tip was guided in coronary artery for in vivo and ex vivo acquisitions. Dual gating in humans with suspected cardiac disorders was performed using 18-F-FDG as a tracer. The method was found feasible for in vivo imaging and the radioactive catheter tip was better resolved in gated images. In human studies, the dual gating was found feasible and easy for clinical routine. Maximal movement of myocardial surface in cranio-caudal direction was over 20 mm. The shape of myocardium was clearly different between the gates and papillary muscles become more visible in diastolic images. The first clinical experiences using robust cardiac-respiratory dual gating are encouraging. Further testing in larger clinical populations using tracers designed especially for plaque imaging is warranted. (orig.)

  7. WE-FG-BRA-03: Oxygen Interplay in Hypofractionated Radiotherapy: A Hidden Opportunity

    International Nuclear Information System (INIS)

    Kissick, M; Campos, D; Desai, V; Che Fru, L

    2016-01-01

    Purpose: Local oxygen during a radiotherapy fraction has been shown to change over a full range of the oxygen enhancement ratio (OER) during the same time scale as the treatment fraction. Interplay with local oxygen is then likely a concern, especially for hypofractionation. Our experiments that show a strong role for metabolic dynamics suggesting one could manipulate this interplay for more efficacious treatments. Methods: Two published experiments are presented with the same human head and neck cancer cell line (UM-SCC-22B). One is a cell-specific in vitro prompt response to a 10 Gy dose of orthovotage radiation using fluorescence lifetime imaging (FLIM), benchmarked with a Seahorse assay. The other in vivo study uses autocorrelation analysis with blood oxygen level dependent magnetic resonance imaging (MRI-BOLD) on xenografts. In vivo results are verified with diffuse optics using spectra fitting and photoacoustic measurements. All these measurements are at high time resolution: sampling is one per minute. Results: Interplay happens when the radiosensitivity modulates at the same time scale as the radiation. These results show dynamics at these time scales. 1. The dominant time scale of the acute hypoxia in cell line xenografts is shown to be on the order of minutes to tens of minutes: similar to a metabolic oscillation known as the ‘glycolytic oscillator.’ 2. The radiation dose itself alters metabolism within minutes to tens of minutes also. Conclusion: These results vary with cell type. There is a possibility that special timing and dose levels could be used for radiation. Gating could be used for maximal oxygen during treatment. There is an analogy to the interplay discussions with tumor motion, except that an oxygen interplay could more likely be patient-specific at a more fundamental level.

  8. WE-FG-BRA-03: Oxygen Interplay in Hypofractionated Radiotherapy: A Hidden Opportunity

    Energy Technology Data Exchange (ETDEWEB)

    Kissick, M; Campos, D; Desai, V; Che Fru, L [University of Wisconsin Madison, Madison, WI (United States)

    2016-06-15

    Purpose: Local oxygen during a radiotherapy fraction has been shown to change over a full range of the oxygen enhancement ratio (OER) during the same time scale as the treatment fraction. Interplay with local oxygen is then likely a concern, especially for hypofractionation. Our experiments that show a strong role for metabolic dynamics suggesting one could manipulate this interplay for more efficacious treatments. Methods: Two published experiments are presented with the same human head and neck cancer cell line (UM-SCC-22B). One is a cell-specific in vitro prompt response to a 10 Gy dose of orthovotage radiation using fluorescence lifetime imaging (FLIM), benchmarked with a Seahorse assay. The other in vivo study uses autocorrelation analysis with blood oxygen level dependent magnetic resonance imaging (MRI-BOLD) on xenografts. In vivo results are verified with diffuse optics using spectra fitting and photoacoustic measurements. All these measurements are at high time resolution: sampling is one per minute. Results: Interplay happens when the radiosensitivity modulates at the same time scale as the radiation. These results show dynamics at these time scales. 1. The dominant time scale of the acute hypoxia in cell line xenografts is shown to be on the order of minutes to tens of minutes: similar to a metabolic oscillation known as the ‘glycolytic oscillator.’ 2. The radiation dose itself alters metabolism within minutes to tens of minutes also. Conclusion: These results vary with cell type. There is a possibility that special timing and dose levels could be used for radiation. Gating could be used for maximal oxygen during treatment. There is an analogy to the interplay discussions with tumor motion, except that an oxygen interplay could more likely be patient-specific at a more fundamental level.

  9. Hypofractionated Whole-Breast Radiation Therapy: Does Breast Size Matter?

    Energy Technology Data Exchange (ETDEWEB)

    Hannan, Raquibul, E-mail: Raquibul.Hannan@gmail.com [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Thompson, Reid F.; Chen Yu; Bernstein, Karen; Kabarriti, Rafi; Skinner, William [Department of Radiation Oncology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (United States); Chen, Chin C. [Department of Radiation Oncology, Columbia University Medical Center, New York, New York (United States); Landau, Evan; Miller, Ekeni; Spierer, Marnee; Hong, Linda; Kalnicki, Shalom [Department of Radiation Oncology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (United States)

    2012-11-15

    Purpose: To evaluate the effects of breast size on dose-volume histogram parameters and clinical toxicity in whole-breast hypofractionated radiation therapy using intensity modulated radiation therapy (IMRT). Materials and Methods: In this retrospective study, all patients undergoing breast-conserving therapy between 2005 and 2009 were screened, and qualifying consecutive patients were included in 1 of 2 cohorts: large-breasted patients (chest wall separation >25 cm or planning target volume [PTV] >1500 cm{sub 3}) (n=97) and small-breasted patients (chest wall separation <25 cm and PTV <1500 cm{sub 3}) (n=32). All patients were treated prone or supine with hypofractionated IMRT to the whole breast (42.4 Gy in 16 fractions) followed by a boost dose (9.6 Gy in 4 fractions). Dosimetric and clinical toxicity data were collected and analyzed using the R statistical package (version 2.12). Results: The mean PTV V95 (percentage of volume receiving >= 95% of prescribed dose) was 90.18% and the mean V105 percentage of volume receiving >= 105% of prescribed dose was 3.55% with no dose greater than 107%. PTV dose was independent of breast size, whereas heart dose and maximum point dose to skin correlated with increasing breast size. Lung dose was markedly decreased in prone compared with supine treatments. Radiation Therapy Oncology Group grade 0, 1, and 2 skin toxicities were noted acutely in 6%, 69%, and 25% of patients, respectively, and at later follow-up (>3 months) in 43%, 57%, and 0% of patients, respectively. Large breast size contributed to increased acute grade 2 toxicity (28% vs 12%, P=.008). Conclusions: Adequate PTV coverage with acceptable hot spots and excellent sparing of organs at risk was achieved by use of IMRT regardless of treatment position and breast size. Although increasing breast size leads to increased heart dose and maximum skin dose, heart dose remained within our institutional constraints and the incidence of overall skin toxicity was comparable

  10. Hypofractionated Whole-Breast Radiation Therapy: Does Breast Size Matter?

    International Nuclear Information System (INIS)

    Hannan, Raquibul; Thompson, Reid F.; Chen Yu; Bernstein, Karen; Kabarriti, Rafi; Skinner, William; Chen, Chin C.; Landau, Evan; Miller, Ekeni; Spierer, Marnee; Hong, Linda; Kalnicki, Shalom

    2012-01-01

    Purpose: To evaluate the effects of breast size on dose-volume histogram parameters and clinical toxicity in whole-breast hypofractionated radiation therapy using intensity modulated radiation therapy (IMRT). Materials and Methods: In this retrospective study, all patients undergoing breast-conserving therapy between 2005 and 2009 were screened, and qualifying consecutive patients were included in 1 of 2 cohorts: large-breasted patients (chest wall separation >25 cm or planning target volume [PTV] >1500 cm 3 ) (n=97) and small-breasted patients (chest wall separation 3 ) (n=32). All patients were treated prone or supine with hypofractionated IMRT to the whole breast (42.4 Gy in 16 fractions) followed by a boost dose (9.6 Gy in 4 fractions). Dosimetric and clinical toxicity data were collected and analyzed using the R statistical package (version 2.12). Results: The mean PTV V95 (percentage of volume receiving >= 95% of prescribed dose) was 90.18% and the mean V105 percentage of volume receiving >= 105% of prescribed dose was 3.55% with no dose greater than 107%. PTV dose was independent of breast size, whereas heart dose and maximum point dose to skin correlated with increasing breast size. Lung dose was markedly decreased in prone compared with supine treatments. Radiation Therapy Oncology Group grade 0, 1, and 2 skin toxicities were noted acutely in 6%, 69%, and 25% of patients, respectively, and at later follow-up (>3 months) in 43%, 57%, and 0% of patients, respectively. Large breast size contributed to increased acute grade 2 toxicity (28% vs 12%, P=.008). Conclusions: Adequate PTV coverage with acceptable hot spots and excellent sparing of organs at risk was achieved by use of IMRT regardless of treatment position and breast size. Although increasing breast size leads to increased heart dose and maximum skin dose, heart dose remained within our institutional constraints and the incidence of overall skin toxicity was comparable to that reported in the

  11. Extension of a data-driven gating technique to 3D, whole body PET studies

    International Nuclear Information System (INIS)

    Schleyer, Paul J; O'Doherty, Michael J; Marsden, Paul K

    2011-01-01

    Respiratory gating can be used to separate a PET acquisition into a series of near motion-free bins. This is typically done using additional gating hardware; however, software-based methods can derive the respiratory signal from the acquired data itself. The aim of this work was to extend a data-driven respiratory gating method to acquire gated, 3D, whole body PET images of clinical patients. The existing method, previously demonstrated with 2D, single bed-position data, uses a spectral analysis to find regions in raw PET data which are subject to respiratory motion. The change in counts over time within these regions is then used to estimate the respiratory signal of the patient. In this work, the gating method was adapted to only accept lines of response from a reduced set of axial angles, and the respiratory frequency derived from the lung bed position was used to help identify the respiratory frequency in all other bed positions. As the respiratory signal does not identify the direction of motion, a registration-based technique was developed to align the direction for all bed positions. Data from 11 clinical FDG PET patients were acquired, and an optical respiratory monitor was used to provide a hardware-based signal for comparison. All data were gated using both the data-driven and hardware methods, and reconstructed. The centre of mass of manually defined regions on gated images was calculated, and the overall displacement was defined as the change in the centre of mass between the first and last gates. The mean displacement was 10.3 mm for the data-driven gated images and 9.1 mm for the hardware gated images. No significant difference was found between the two gating methods when comparing the displacement values. The adapted data-driven gating method was demonstrated to successfully produce respiratory gated, 3D, whole body, clinical PET acquisitions.

  12. 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.

  13. Hypofractionation Regimens for Stereotactic Radiotherapy for Large Brain Tumors

    International Nuclear Information System (INIS)

    Yuan Jiankui; Wang, Jian Z.; Lo, Simon; Grecula, John C.; Ammirati, Mario; Montebello, Joseph F.; Zhang Hualin; Gupta, Nilendu; Yuh, William T.C.; Mayr, Nina A.

    2008-01-01

    Purpose: To investigate equivalent regimens for hypofractionated stereotactic radiotherapy (HSRT) for brain tumor treatment and to provide dose-escalation guidance to maximize the tumor control within the normal brain tolerance. Methods and Materials: The linear-quadratic model, including the effect of nonuniform dose distributions, was used to evaluate the HSRT regimens. The α/β ratio was estimated using the Gammaknife stereotactic radiosurgery (GKSRS) and whole-brain radiotherapy experience for large brain tumors. The HSRT regimens were derived using two methods: (1) an equivalent tumor control approach, which matches the whole-brain radiotherapy experience for many fractions and merges it with the GKSRS data for few fractions; and (2) a normal-tissue tolerance approach, which takes advantages of the dose conformity and fractionation of HSRT to approach the maximal dose tolerance of the normal brain. Results: A plausible α/β ratio of 12 Gy for brain tumor and a volume parameter n of 0.23 for normal brain were derived from the GKSRS and whole-brain radiotherapy data. The HSRT prescription regimens for the isoeffect of tumor irradiation were calculated. The normal-brain equivalent uniform dose decreased as the number of fractions increased, because of the advantage of fractionation. The regimens for potential dose escalation of HSRT within the limits of normal-brain tolerance were derived. Conclusions: The designed hypofractionated regimens could be used as a preliminary guide for HSRT dose prescription for large brain tumors to mimic the GKSRS experience and for dose escalation trials. Clinical studies are necessary to further tune the model parameters and validate these regimens

  14. Adoption of Hypofractionated Radiation Therapy for Breast Cancer After Publication of Randomized Trials

    International Nuclear Information System (INIS)

    Jagsi, Reshma; Falchook, Aaron D.; Hendrix, Laura H.; Curry, Heather; Chen, Ronald C.

    2014-01-01

    Purpose: Large randomized trials have established the noninferiority of shorter courses of “hypofractionated” radiation therapy (RT) to the whole breast compared to conventional courses using smaller daily doses in the adjuvant treatment of selected breast cancer patients undergoing lumpectomy. Hypofractionation is more convenient and less costly. Therefore, we sought to determine uptake of hypofractionated breast RT over time. Methods and Materials: In the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database, we identified 16,096 women with node-negative breast cancer and 4269 with ductal carcinoma in situ (DCIS) who received lumpectomy followed by more than 12 fractions of RT between 2004 and 2010. Based on Medicare claims, we determined the number of RT treatments given and grouped patients into those receiving hypofractionation (13-24) or those receiving conventional fractionation (≥25). We also determined RT technique (intensity modulated RT or not) using Medicare claims. We evaluated patterns and correlates of hypofractionation receipt using bivariate and multivariable analyses. Results: Hypofractionation use was similar in patients with DCIS and those with invasive disease. Overall, the use of hypofractionation increased from 3.8% in 2006 to 5.4% in 2007, to 9.4% in 2008, and to 13.6% in 2009 and 2010. Multivariable analysis showed increased use of hypofractionation in recent years and in patients with older age, smaller tumors, increased comorbidity, higher regional education, and Western SEER regions. However, even in patients over the age of 80, the hypofractionation rate in 2009 to 2010 was only 25%. Use of intensity modulated RT (IMRT) also increased over time (from 9.4% in 2004 to 22.7% in 2009-2010) and did not vary significantly between patients receiving hypofractionation and those receiving traditional fractionation. Conclusions: Hypofractionation use increased among low-risk older US breast cancer patients with

  15. Adoption of Hypofractionated Radiation Therapy for Breast Cancer After Publication of Randomized Trials

    Energy Technology Data Exchange (ETDEWEB)

    Jagsi, Reshma, E-mail: rjagsi@med.umich.edu [Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, Michigan (United States); Falchook, Aaron D.; Hendrix, Laura H. [Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Curry, Heather [Radiation Oncology, Eviti, Inc, Philadelphia, Pennsylvania (United States); Chen, Ronald C. [Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States)

    2014-12-01

    Purpose: Large randomized trials have established the noninferiority of shorter courses of “hypofractionated” radiation therapy (RT) to the whole breast compared to conventional courses using smaller daily doses in the adjuvant treatment of selected breast cancer patients undergoing lumpectomy. Hypofractionation is more convenient and less costly. Therefore, we sought to determine uptake of hypofractionated breast RT over time. Methods and Materials: In the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database, we identified 16,096 women with node-negative breast cancer and 4269 with ductal carcinoma in situ (DCIS) who received lumpectomy followed by more than 12 fractions of RT between 2004 and 2010. Based on Medicare claims, we determined the number of RT treatments given and grouped patients into those receiving hypofractionation (13-24) or those receiving conventional fractionation (≥25). We also determined RT technique (intensity modulated RT or not) using Medicare claims. We evaluated patterns and correlates of hypofractionation receipt using bivariate and multivariable analyses. Results: Hypofractionation use was similar in patients with DCIS and those with invasive disease. Overall, the use of hypofractionation increased from 3.8% in 2006 to 5.4% in 2007, to 9.4% in 2008, and to 13.6% in 2009 and 2010. Multivariable analysis showed increased use of hypofractionation in recent years and in patients with older age, smaller tumors, increased comorbidity, higher regional education, and Western SEER regions. However, even in patients over the age of 80, the hypofractionation rate in 2009 to 2010 was only 25%. Use of intensity modulated RT (IMRT) also increased over time (from 9.4% in 2004 to 22.7% in 2009-2010) and did not vary significantly between patients receiving hypofractionation and those receiving traditional fractionation. Conclusions: Hypofractionation use increased among low-risk older US breast cancer patients with

  16. Clinical benefits of new immobilization system for hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma by helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yong; Zhou, Yong-Kang; Chen, Yi-Xing; Shi, Shi-Ming; Zeng, Zhao-Chong, E-mail: zeng.zhaochong@zs-hospital.sh.cn

    2017-04-01

    Objective: A comprehensive clinical evaluation was conducted, assessing the Body Pro-Lok immobilization and positioning system to facilitate hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma (HCC), using helical tomotherapy to improve treatment precision. Methods: Clinical applications of the Body Pro-Lok system were investigated (as above) in terms of interfractional and intrafractional setup errors and compressive abdominal breath control. To assess interfractional setup errors, a total of 42 patients who were given 5 to 20 fractions of helical tomotherapy for intrahepatic HCC were analyzed. Overall, 15 patients were immobilized using simple vacuum cushion (group A), and the Body Pro-Lok system was used in 27 patients (group B), performing megavoltage computed tomography (MVCT) scans 196 times and 435 times, respectively. Pretreatment MVCT scans were registered to the planning kilovoltage computed tomography (KVCT) for error determination, and group comparisons were made. To establish intrafractional setup errors, 17 patients with intrahepatic HCC were selected at random for immobilization by Body Pro-Lok system, undergoing MVCT scans after helical tomotherapy every week. A total of 46 MVCT re-scans were analyzed for this purpose. In researching breath control, 12 patients, randomly selected, were immobilized by Body Pro-Lok system and subjected to 2-phase 4-dimensional CT (4DCT) scans, with compressive abdominal control or in freely breathing states, respectively. Respiratory-induced liver motion was then compared. Results: Mean interfractional setup errors were as follows: (1) group A: X, 2.97 ± 2.47 mm; Y, 4.85 ± 4.04 mm; and Z, 3.77 ± 3.21 mm; pitch, 0.66 ± 0.62°; roll, 1.09 ± 1.06°; and yaw, 0.85 ± 0.82°; and (2) group B: X, 2.23 ± 1.79 mm; Y, 4.10 ± 3.36 mm; and Z, 1.67 ± 1.91 mm; pitch, 0.45 ± 0.38°; roll, 0.77 ± 0.63°; and yaw, 0.52 ± 0.49°. Between-group differences were statistically significant in 6 directions (p

  17. Clinical benefits of new immobilization system for hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma by helical tomotherapy

    International Nuclear Information System (INIS)

    Hu, Yong; Zhou, Yong-Kang; Chen, Yi-Xing; Shi, Shi-Ming; Zeng, Zhao-Chong

    2017-01-01

    Objective: A comprehensive clinical evaluation was conducted, assessing the Body Pro-Lok immobilization and positioning system to facilitate hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma (HCC), using helical tomotherapy to improve treatment precision. Methods: Clinical applications of the Body Pro-Lok system were investigated (as above) in terms of interfractional and intrafractional setup errors and compressive abdominal breath control. To assess interfractional setup errors, a total of 42 patients who were given 5 to 20 fractions of helical tomotherapy for intrahepatic HCC were analyzed. Overall, 15 patients were immobilized using simple vacuum cushion (group A), and the Body Pro-Lok system was used in 27 patients (group B), performing megavoltage computed tomography (MVCT) scans 196 times and 435 times, respectively. Pretreatment MVCT scans were registered to the planning kilovoltage computed tomography (KVCT) for error determination, and group comparisons were made. To establish intrafractional setup errors, 17 patients with intrahepatic HCC were selected at random for immobilization by Body Pro-Lok system, undergoing MVCT scans after helical tomotherapy every week. A total of 46 MVCT re-scans were analyzed for this purpose. In researching breath control, 12 patients, randomly selected, were immobilized by Body Pro-Lok system and subjected to 2-phase 4-dimensional CT (4DCT) scans, with compressive abdominal control or in freely breathing states, respectively. Respiratory-induced liver motion was then compared. Results: Mean interfractional setup errors were as follows: (1) group A: X, 2.97 ± 2.47 mm; Y, 4.85 ± 4.04 mm; and Z, 3.77 ± 3.21 mm; pitch, 0.66 ± 0.62°; roll, 1.09 ± 1.06°; and yaw, 0.85 ± 0.82°; and (2) group B: X, 2.23 ± 1.79 mm; Y, 4.10 ± 3.36 mm; and Z, 1.67 ± 1.91 mm; pitch, 0.45 ± 0.38°; roll, 0.77 ± 0.63°; and yaw, 0.52 ± 0.49°. Between-group differences were statistically significant in 6 directions (p

  18. Hypofractionated conformal radiotherapy (HCRT) for primary and metastatic lung cancers with small dimension. Efficacy and toxicity

    International Nuclear Information System (INIS)

    Mirri, Maria Alessandra; Arcangeli, Giorgio; Pinzi, Valentina; Benassi, Marcello; D'Angelo, Annelisa; Strigari, Lidia; Caterino, Mauro; Rinaldi, Massimo; Ceribelli, Anna

    2009-01-01

    Purpose: to report on the clinical outcome of hypofractionated conformal radiotherapy (HCRT) for medically inoperable stage I non-small cell lung carcinoma (NSCLC) or limited pulmonary metastases ≤ 5 cm in diameter. Patients and methods: from June 2003 to March 2007, 40 patients (42 lesions) underwent HCRT consisting of 40 Gy in five fractions over 2.5 weeks received by at least 95% of planning target volume. All patients underwent CT simulation and treatment under free shallow breathing. To evaluate target displacement under respiratory activity, two additional CT scans were performed with breath-holding during the expiratory and inspiratory phases. Of all patients enrolled, those with a follow-up ≥ 4 months were considered suitable for analysis. Local response was evaluated with CT imaging 4 months after the end of HCRT and every 3 months thereafter. Local relapse-free survival (LRFS) and overall survival (OS) were calculated with the Kaplan-Meier method. Results: local response to the treatment was complete response, partial response, no change, and progressive disease as seen in 29%, 43%, 14%, and 7% of tumors, respectively. LRFS at 1 year and 3 years was 76% and 63%, respectively. Lung toxicities ≥ grade 2 were observed in 4/40 patients, but no grade 4. Pericardial effusion occurred in one patient. In stage I NSCLC patients (n = 15) with a median follow-up of 25 months, the 1-year LRFS and OS rates were 88% and 81%, respectively, and the 3-year rates 72% and 61%, respectively. Conclusion: HCRT is an effective and low-toxic treatment for medically inoperable early-stage lung cancers and pulmonary metastases for all clinicians lacking the aid of a dedicated stereotactic system. (orig.)

  19. Synchrony - Cyberknife Respiratory Compensation Technology

    International Nuclear Information System (INIS)

    Ozhasoglu, Cihat; Saw, Cheng B.; Chen Hungcheng; Burton, Steven; Komanduri, Krishna; Yue, Ning J.; Huq, Saiful M.; Heron, Dwight E.

    2008-01-01

    Studies of organs in the thorax and abdomen have shown that these organs can move as much as 40 mm due to respiratory motion. Without compensation for this motion during the course of external beam radiation therapy, the dose coverage to target may be compromised. On the other hand, if compensation of this motion is by expansion of the margin around the target, a significant volume of normal tissue may be unnecessarily irradiated. In hypofractionated regimens, the issue of respiratory compensation becomes an important factor and is critical in single-fraction extracranial radiosurgery applications. CyberKnife is an image-guided radiosurgery system that consists of a 6-MV LINAC mounted to a robotic arm coupled through a control loop to a digital diagnostic x-ray imaging system. The robotic arm can point the beam anywhere in space with 6 degrees of freedom, without being constrained to a conventional isocenter. The CyberKnife has been recently upgraded with a real-time respiratory tracking and compensation system called Synchrony. Using external markers in conjunction with diagnostic x-ray images, Synchrony helps guide the robotic arm to move the radiation beam in real time such that the beam always remains aligned with the target. With the aid of Synchrony, the tumor motion can be tracked in three-dimensional space, and the motion-induced dosimetric change to target can be minimized with a limited margin. The working principles, advantages, limitations, and our clinical experience with this new technology will be discussed

  20. The relation between respiratory motion artifact correction and lung standardized uptake value

    International Nuclear Information System (INIS)

    Yin Lijie; Liu Xiaojian; Liu Jie; Xu Rui; Yan Jue

    2014-01-01

    PET/CT is playing an important role in disease diagnosis and therapeutic evaluation. But the respiratory motion artifact may bring trouble in diagnosis and therapy. There are many methods to correct the respiratory motion artifact. Respiratory gated PET/CT is applied most extensively of them. Using respiratory gated PET/CT to correct respiratory motion artifact can increase the maximum standardized uptake value of lung lesion obviously, thereby improving the quality of image and accuracy of diagnosis. (authors)

  1. Respiratory alkalosis

    Science.gov (United States)

    Alkalosis - respiratory ... leads to shortness of breath can also cause respiratory alkalosis (such as pulmonary embolism and asthma). ... Treatment is aimed at the condition that causes respiratory alkalosis. Breathing into a paper bag -- or using ...

  2. Radiobiology of hypofractionated stereotactic radiotherapy: what are the optimal fractionation schedules?

    International Nuclear Information System (INIS)

    Shibamoto, Yuta; Miyakawa, Akifumi; Otsuka, Shinya; Iwata, Hiromitsu

    2016-01-01

    In hypofractionated stereotactic radiotherapy (SRT), high doses per fraction are usually used and the dose delivery pattern is different from that of conventional radiation. The daily dose is usually given intermittently over a longer time compared with conventional radiotherapy. During prolonged radiation delivery, sublethal damage repair takes place, leading to the decreased effect of radiation. In in vivo tumors, however, this decrease in effect may be counterbalanced by rapid reoxygenation. Another issue related to hypofractionated SRT is the mathematical model for dose evaluation and conversion. The linear–quadratic (LQ) model and biologically effective dose (BED) have been suggested to be incorrect when used for hypofractionation. The LQ model overestimates the effect of high fractional doses of radiation. BED is particularly incorrect when used for tumor responses in vivo, since it does not take reoxygenation into account. Correction of the errors, estimated at 5–20%, associated with the use of BED is necessary when it is used for SRT. High fractional doses have been reported to exhibit effects against tumor vasculature and enhance host immunity, leading to increased antitumor effects. This may be an interesting topic that should be further investigated. Radioresistance of hypoxic tumor cells is more problematic in hypofractionated SRT, so trials of hypoxia-targeted agents are encouraged in the future. In this review, the radiobiological characteristics of hypofractionated SRT are summarized, and based on the considerations, we would like to recommend 60 Gy in eight fractions delivered three times a week for lung tumors larger than 2 cm in diameter

  3. SU-G-JeP3-13: Use of Volumetric Indices to Study the Viability of Respiratory Gating in Conjunction with Abdominal Compression in the Management of Non-Small Cell Lung Cancer Tumors Using Stereotactic Body Radiation Therapy Under the Conditions of Controlled Breathing

    Energy Technology Data Exchange (ETDEWEB)

    Malhotra, H; Gomez, J [Roswell Park Cancer Institute, Buffalo, NY (United States)

    2016-06-15

    Purpose: AAPM TG-76 report advises lung patients experiencing tumor motion >5mm to use some form of motion management with even smaller limit for complex/special procedures like SBRT. Generally, either respiratory gating or abdominal compression is used for motion management. In this retrospective study, we are using an innovative index, Volumetric Indices (VI) = (GTVnn AND GTV{sub 50+}Xmm)/(GTVnn) to quantify how much of the tumor remains within 1, 2, and 3mm margins throughout the breathing cycle using GTV{sub 50+}Xmm margin on GTV{sub 50}[nn=0,10,20,…90]. Using appropriate limits, VI can provide tumor motion information and to check if RPM gates could have been used in conjunction with abdominal compression to better manage tumor motion. Methods: 64 SBRT patients with a total of 67 lung tumors were studied. 4DCT scans were taken, fully capturing tumor motion throughout the 10 phases of the breathing cycle. For each phase, Gross Tumor Volume (GTV) was segmented and appropriates structures were defined to determine VI values. For the 2mm margin, VI values less than 0.95 for peripheral lesions and 0.97 for central lesions indicate tumor movement greater than 4mm. VI values for 1mm and 3mm margins were also analyzed signifying tumor motion of 2mm & 6mm, respectively. Results: Of the 64 patients, 35 (55%) had motion greater than 4mm & could have benefited from respiratory gating. For 5/8 (63%) middle lobe lesions, 21/27 (78%) lower lobe lesions, and 10/32 (31%) upper lobe lesions, gating could have resulted in smaller ITV. 32/55 (58%) peripheral lesions and 4/12 (33%) central lesions could have had gating. Average ITV decreased by 1.25cc (11.43%) and average VI increased by 0.11. Conclusion: Out of 64 patients, 55% exhibited motion greater than 4mm even with abdominal compression. Even with abdominalcompression, lung tumors can move >4mm as the degree of pressure which a patient can tolerate, is patient specific.

  4. Dual-gated volumetric modulated arc therapy

    International Nuclear Information System (INIS)

    Fahimian, Benjamin; Wu, Junqing; Wu, Huanmei; Geneser, Sarah; Xing, Lei

    2014-01-01

    Gated Volumetric Modulated Arc Therapy (VMAT) is an emerging radiation therapy modality for treatment of tumors affected by respiratory motion. However, gating significantly prolongs the treatment time, as delivery is only activated during a single respiratory phase. To enhance the efficiency of gated VMAT delivery, a novel dual-gated VMAT (DG-VMAT) technique, in which delivery is executed at both exhale and inhale phases in a given arc rotation, is developed and experimentally evaluated. Arc delivery at two phases is realized by sequentially interleaving control points consisting of MUs, MLC sequences, and angles of VMAT plans generated at the exhale and inhale phases. Dual-gated delivery is initiated when a respiration gating signal enters the exhale window; when the exhale delivery concludes, the beam turns off and the gantry rolls back to the starting position for the inhale window. The process is then repeated until both inhale and exhale arcs are fully delivered. DG-VMAT plan delivery accuracy was assessed using a pinpoint chamber and diode array phantom undergoing programmed motion. DG-VMAT delivery was experimentally implemented through custom XML scripting in Varian’s TrueBeam™ STx Developer Mode. Relative to single gated delivery at exhale, the treatment time was improved by 95.5% for a sinusoidal breathing pattern. The pinpoint chamber dose measurement agreed with the calculated dose within 0.7%. For the DG-VMAT delivery, 97.5% of the diode array measurements passed the 3%/3 mm gamma criterion. The feasibility of DG-VMAT delivery scheme has been experimentally demonstrated for the first time. By leveraging the stability and natural pauses that occur at end-inspiration and end-exhalation, DG-VMAT provides a practical method for enhancing gated delivery efficiency by up to a factor of two

  5. The hypo-fractionated radiotherapy in the treatment of the prostate cancer: Radiate less to treat more

    International Nuclear Information System (INIS)

    Boissier, R.; Gross, E.

    2012-01-01

    The principle of the hypo-fractionation in radiotherapy is to deliver a higher dose by session and to reduce the duration of treatment. In the particular case of the cancer of prostate, a hypo-fractionated protocol allows to deliver an equivalent radiobiological dose identical even higher than a standard plan of irradiation. The hypo-fractionation is presented as a solution to improve the access to the care (fewer processing times by patient, more patients treated by machine) while increasing the quality of the care: better carcinological control, less radiotoxicity. The objective of this article is to make a clarification on the hypo-fractionated radiotherapy in first intention in the treatment of the localized prostate cancer. We count three studies on large cohorts, comparing standard plans to 1.8 2 Gy/session and hypo-fractionated plans (2.5 3 Gy/session). The inferior carcinological results of the two first comparative studies with regard to the study of phase I/II of the Cleveland clinic were owed to a sub-dosage of hypo-fractionated plans. The administered equivalent biological doses were lower than the at present recommended total doses and lower than the theoretical doses, calculated on the bases of an erroneous evaluation of the radio-sensibility of the prostate cancer. In the comparative study of Arcangeli, the rate of survival without biological recurrence in 4 years (82%) was significantly to the advantage of the hypo-fractionated group, while reducing the duration of treatment of 3 weeks. Four comparative studies reported acute/late toxicity, gastrointestinal (GI)/genito-urinary acceptable (GU) even lower with a hypo-fractionated plan. The hypo-fractionation is potentially the future of the radiotherapy in the treatment of the localized prostate cancer thanks to the technological innovation, but for all that does not constitute at present a standard. (authors)

  6. Hypofractionated radiation therapy for the treatment of feline facial squamous cell carcinoma; Hypofractionated radiation therapy for the treatment of feline facial squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, S.C.S.; Corgozinho, K.B.; Holguin, P.G.; Ferreira, A.M.R., E-mail: simonecsc@gmail.co [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Carvalho, L.A.V. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil); Canary, P.C.; Reisner, M. [Hospital Universitario Clementino Fraga Filho (HUCFF/UFRJ), Rio de Janeiro, RJ (Brazil); Pereira, A.N.; Souza, H.J.M. [Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropedica, RJ (Brazil)

    2010-07-01

    The efficacy of hypofractionated radiation protocol for feline facial squamous cell carcinoma was evaluated. Hypofractionated radiation therapy was applied to five cats showing single or multiple facial squamous cell carcinomas, in a total of ten histologically confirmed neoplastic lesions. Of the lesions, two were staged as T{sub 1}, four as T{sub 2}, two as T{sub 3}, and two as T{sub 4}. The animals were submitted to four radiation fractions from 7.6 to 10 grays each, with one week intervals. The equipment was a linear accelerator with electrons beam. The cats were evaluated weekly during the treatment and 30 and 60 days after the end of the radiation therapy. In this study, 40% of the lesions had complete remission, 40% partial remission, and 20% did not respond to the treatment. Response rates were lower as compared to other protocols previously used. However, hypofractionated radiation protocol was considered safe for feline facial squamous cell carcinoma. (author)

  7. The Role of Hypofractionated Radiation Therapy with Photons, Protons and Heavy Ions for Treating Extracranial Lesions

    Directory of Open Access Journals (Sweden)

    Aaron Michael Laine

    2016-01-01

    Full Text Available Traditionally, the ability to deliver large doses of ionizing radiation to a tumor has been limited by radiation induced toxicity to normal surrounding tissues. This was the initial impetus for the development of conventionally fractionated radiation therapy, where large volumes of healthy tissue received radiation and were allowed the time to repair the radiation damage. However, advances in radiation delivery techniques and image guidance have allowed for more ablative doses of radiation to be delivered in a very accurate, conformal and safe manner with shortened fractionation schemes. Hypofractionated regimens with photons have already transformed how certain tumor types are treated with radiation therapy. Additionally, hypofractionation is able to deliver a complete course of ablative radiation therapy over a shorter period of time compared to conventional fractionation regimens making treatment more convenient to the patient and potentially more cost-effective. Recently there has been an increased interest in proton therapy because of the potential further improvement in dose distributions achievable due to their unique physical characteristics. Furthermore, with heavier ions the dose conformality is increased and in addition there is potentially a higher biological effectiveness compared to protons and photons. Due to the properties mentioned above, charged particle therapy has already become an attractive modality to further investigate the role of hypofractionation in the treatment of various tumors. This review will discuss the rationale and evolution of hypofractionated radiation therapy, the reported clinical success with initially photon and then charged particle modalities, and further potential implementation into treatment regimens going forward.

  8. Rise and fall of hypofractionation in clinical radiotherapy in the 20th century

    International Nuclear Information System (INIS)

    Friberg, S.; Ruden, B. I.

    2007-01-01

    The purpose of this article is to review of the use of hypofractionated radiotherapy during the last two centuries. We define hypofractionation as any treatment where the individual fraction exceeds 2.0 Gray (Gy). The number of fractions is disregarded. The struggle of the early radiotherapists, the slow acceptance of fractionation, and the battle between the German and the French schools are reviewed. The early mathematical formulae of biological effects radiation are described and commented on. The paramount contribution in radiotherapy by British scientists gave rise to a new science: radiobiology. This branch had now matured into an exact discipline, separate from, and yet utterly depending on, its 100 years old sibling: Diagnostic Radiology. The come-back and fall of hypofractionation during two centuries is described, and set in relation to the treatment philosophy of the corresponding period. Injuries are described, and the long latency period for late reactions pointed out. Some of the legal aspects of the injuries are discussed. The come-back of hypofractionation - twice declared dead and buried the 20 th century - in the late 1990's is explained. The brilliant incorporation variability (α andβ) into mathematical exactness (the LQ-formula) has had, and will have a profound impact on clinical radiotherapy. (author)

  9. Hypofractionated IMRT of the Prostate Bed After Radical Prostatectomy: Acute Toxicity in the PRIAMOS-1 Trial

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, Sonja, E-mail: sonja.katayama@med.uni-heidelberg.de [Department of Radiation Oncology, University Hospital Heidelberg, Im Neuenheimer Feld, Heidelberg (Germany); Striecker, Thorbjoern; Kessel, Kerstin [Department of Radiation Oncology, University Hospital Heidelberg, Im Neuenheimer Feld, Heidelberg (Germany); Sterzing, Florian [Department of Radiation Oncology, University Hospital Heidelberg, Im Neuenheimer Feld, Heidelberg (Germany); Department of Radiation Oncology, German Cancer Research Center, Im Neuenheimer Feld, Heidelberg (Germany); Habl, Gregor [Department of Radiation Oncology, University Hospital Heidelberg, Im Neuenheimer Feld, Heidelberg (Germany); Edler, Lutz [Department of Biostatistics, German Cancer Research Center, Im Neuenheimer Feld, Heidelberg (Germany); Debus, Juergen [Department of Radiation Oncology, University Hospital Heidelberg, Im Neuenheimer Feld, Heidelberg (Germany); Department of Radiation Oncology, German Cancer Research Center, Im Neuenheimer Feld, Heidelberg (Germany); Herfarth, Klaus [Department of Radiation Oncology, University Hospital Heidelberg, Im Neuenheimer Feld, Heidelberg (Germany)

    2014-11-15

    Purpose: Hypofractionated radiation therapy as primary treatment for prostate cancer is currently being investigated in large phase 3 trials. However, there are few data on postoperative hypofractionation. The Radiation therapy for the Prostate Bed With or Without the Pelvic Lymph Nodes (PRIAMOS 1) trial was initiated as a prospective phase 2 trial to assess treatment safety and toxicity of a hypofractionated intensity modulated radiation therapy (IMRT) of the prostate bed. Methods and Materials: From February to September 2012, 40 patients with indications for adjuvant or salvage radiation therapy were enrolled. One patient dropped out before treatment. Patients received 54 Gy in 18 fractions to the prostate bed with IMRT and daily image guidance. Gastrointestinal (GI) and genitourinary (GU) toxicities (according to National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0) were recorded weekly during treatment and 10 weeks after radiation therapy. Results: Overall acute toxicity was favorable, with no recorded adverse events grade ≥3. Acute GI toxicity rates were 56.4% (grade 1) and 17.9% (grade 2). Acute GU toxicity was recorded in 35.9% of patients (maximum grade 1). Urinary stress incontinence was not influenced by radiation therapy. The incidence of grade 1 urinary urge incontinence increased from 2.6% before to 23.1% 10 weeks after therapy, but grade 2 urge incontinence remained unchanged. Conclusions: Postoperative hypofractionated IMRT of the prostate bed is tolerated well, with no severe acute side effects.

  10. Reproducibility and geometric accuracy of the fixster system during hypofractionated stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Lindvall, Peter; Bergström, Per; Löfroth, Per-Olov; Henriksson, Roger; Bergenheim, A Tommy

    2008-01-01

    Hypofractionated radiotherapy has been used for the treatment of AVMs and brain metastases. Hypofractionation necessitates the use of a relocatable stereotactic frame that has to be applied on several occasions. The stereotactic frame needs to have a high degree of reproducibility, and patient positioning is crucial to achieve a high accuracy of the treatment. In this study we have, by radiological means, evaluated the reproducibility of the isocenter in consecutive treatment sessions using the Fixster frame. Deviations in the X, Y and Z-axis were measured in 10 patients treated with hypofractionated radiotherapy. The mean deviation in the X-axis was 0.4 mm (range -2.1 – 2.1, median 0.7 mm) and in the Y-axis -0.3 mm (range -1.4 – 0.7, median -0.2 mm). The mean deviation in the Z-axis was -0.6 (range -1.4 – 1.4, median 0.0 mm). There is a high degree of reproducibility of the isocenter during successive treatment sessions with HCSRT using the Fixster frame for stereotactic targeting. The high reducibility enables a safe treatment using hypofractionated stereotactic radiotherapy

  11. SU-E-T-350: Verification of Gating Performance of a New Elekta Gating Solution: Response Kit and Catalyst System

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X; Cao, D; Housley, D; Mehta, V; Shepard, D [Swedish Cancer Institute, Seattle, WA (United States)

    2014-06-01

    Purpose: In this work, we have tested the performance of new respiratory gating solutions for Elekta linacs. These solutions include the Response gating and the C-RAD Catalyst surface mapping system.Verification measurements have been performed for a series of clinical cases. We also examined the beam on latency of the system and its impact on delivery efficiency. Methods: To verify the benefits of tighter gating windows, a Quasar Respiratory Motion Platform was used. Its vertical-motion plate acted as a respiration surrogate and was tracked by the Catalyst system to generate gating signals. A MatriXX ion-chamber array was mounted on its longitudinal-moving platform. Clinical plans are delivered to a stationary and moving Matrix array at 100%, 50% and 30% gating windows and gamma scores were calculated comparing moving delivery results to the stationary result. It is important to note that as one moves to tighter gating windows, the delivery efficiency will be impacted by the linac's beam-on latency. Using a specialized software package, we generated beam-on signals of lengths of 1000ms, 600ms, 450ms, 400ms, 350ms and 300ms. As the gating windows get tighter, one can expect to reach a point where the dose rate will fall to nearly zero, indicating that the gating window is close to beam-on latency. A clinically useful gating window needs to be significantly longer than the latency for the linac. Results: As expected, the use of tighter gating windows improved delivery accuracy. However, a lower limit of the gating window, largely defined by linac beam-on latency, exists at around 300ms. Conclusion: The Response gating kit, combined with the C-RAD Catalyst, provides an effective solution for respiratorygated treatment delivery. Careful patient selection, gating window design, even visual/audio coaching may be necessary to ensure both delivery quality and efficiency. This research project is funded by Elekta.

  12. Respiratory Failure

    Science.gov (United States)

    Respiratory failure happens when not enough oxygen passes from your lungs into your blood. Your body's organs, ... brain, need oxygen-rich blood to work well. Respiratory failure also can happen if your lungs can' ...

  13. Respiratory system

    Science.gov (United States)

    Bartlett, R. G., Jr.

    1973-01-01

    The general anatomy and function of the human respiratory system is summarized. Breathing movements, control of breathing, lung volumes and capacities, mechanical relations, and factors relevant to respiratory support and equipment design are discussed.

  14. [Practice evolution of hypofractionation in breast radiation therapy and medical impact].

    Science.gov (United States)

    Dupin, C; Vilotte, F; Lagarde, P; Petit, A; Breton-Callu, C

    2016-06-01

    Whole breast irradiation after conservative surgery is the standard treatment for invasive breast cancer. Randomized studies indicate that hypofractionation can be equivalent for selected patients. This study focuses on fractionation practice evolution in a single centre, and analyses the economic impact of practice modification. All prescriptions for invasive breast cancer between January 2010 and June 2014 were analyzed. Female patients 60 years or older, pN0 were considered for the economic study. Patients included in clinical trials or patient with high-grade tumours were excluded from the hypofractionation practice study, because physician could not choose fractionation. We used data from the Medical public health system to calculate cost per fraction and transportation cost. Two thousand thirty one patients were treated; 399 were eligible for the economic study (20%) and 282 for the practice study (14%). Treatment with 25 fractions decreased from 90% to 16% in the first half of 2014. Meanwhile, treatment with 15 or 16 fractions increased from 6% in 2010 to 68% in the first half of 2014. Hypofractionated treatment proportion was 100% with 42.5Gy in 16 fractions in 2010 and 100% 40Gy in 15 fractions in 2014, according to long-term follow-up publication of START trials. Treatment with five fractions remained stable around 7% (4 to 16%), reserved for patients over 80 years (PPractice change led to an increase of hypofractionation in recent years. Hypofractionation may be currently prescribed and may concern 20% of patients. This practice evolution is beneficial for patients and the public health system. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  15. Gated listmode acquisition with the QuadHIDAC animal PET to image mouse hearts

    International Nuclear Information System (INIS)

    Schaefers, K.P.; Lang, N.; Stegger, L.; Schober, O.; Schaefers, M.

    2006-01-01

    Purpose: the aim of this study was to develop ECG and respiratory gating in combination with listmode acquisition for the quadHIDAC small-animal PET scanner. Methods: ECG and respiratory gating was realized with the help of an external trigger device (BioVET) synchronized with the listmode acquisition. Listmode data of a mouse acquisition (injected with 6.5 MBq of 18 F-FDG) were sorted according to three different gating definitions: 12 cardiac gates, 8 respiratory gates and a combination of 8 cardiac and 8 respiratory gates. Images were reconstructed with filtered back-projection (ramp filter), and parameters like left ventricular wall thickness (WT), wall-to-wall separation (WS) and blood to myocardium activity ratios (BMR) were calculated. Results: cardiac gated images show improvement of all parameters (WT 2.6 mm, WS 4.1 mm, BRM 2.3) in diastole compared to ungated images (WT 3.0 mm, WS 3.4 mm, BMR 1.3). Respiratory gating had little effect on calculated parameters. Conclusion: ECG gating with the quadHIDAC can improve myocardial image quality in mice. This could have a major impact on the calculation of an image-derived input function for kinetic modelling. (orig.)

  16. New gate opening hours

    CERN Multimedia

    GS Department

    2009-01-01

    Please note the new opening hours of the gates as well as the intersites tunnel from the 19 May 2009: GATE A 7h - 19h GATE B 24h/24 GATE C 7h - 9h\t17h - 19h GATE D 8h - 12h\t13h - 16h GATE E 7h - 9h\t17h - 19h Prévessin 24h/24 The intersites tunnel will be opened from 7h30 to 18h non stop. GS-SEM Group Infrastructure and General Services Department

  17. Acute radiation dermatitis and pneumonitis in Japanese breast cancer patients with whole breast hypofractionated radiotherapy compared to conventional radiotherapy

    International Nuclear Information System (INIS)

    Osako, Tomo; Oguchi, Masahiko; Kumada, Madoka; Nemoto, Keiko; Iwase, Takuji; Yamashita, Takashi

    2008-01-01

    The objective of this study was to evaluate acute morbidity, radiation dermatitis and pneumonitis, of Japanese patients treated with whole breast hypofractionated radiotherapy (RT) after breast-conserving surgery (BCS), compared to conventional RT. Japanese patients who received whole breast RT after BCS between October 2003 and September 2006 were retrospectively reviewed. Patients who had selected the conventional or hypofractionated schedule received whole breast irradiation of 50 Gy in 25 fractions plus boost or 40 Gy in 16 fractions plus boost. Radiation dermatitis and symptomatic pneumonitis were graded according to the Common Terminology Criteria for Adverse Events version 3.0. Of 443 consecutive patients, 377 (85%) received the conventional schedule and 66 (15%) received the hypofractionated schedule. Of patients treated with the conventional schedule, Grade 0, 1, 2 and 3 radiation dermatitis were observed in 16 (4%), 278 (74%), 77 (20%) and 6 (2%), respectively. Of patients treated with the hypofractionated schedule, Grade 0, 1, 2 and 3 dermatitis were observed in 11 (17%), 49 (74%), 5 (8%) and 1 (1%), respectively. Grade 2-3 dermatitis by the hypofractionated schedule (9%) was observed less frequently than that by the conventional schedule (22%) (chi-square test; P=0.016). Moreover, of patients treated with the conventional schedule, 4 (1%) had Grade 2 radiation pneumonitis. No patient treated with the hypofractionated schedule had symptomatic pneumonitis. Radiation dermatitis and pneumonitis in Japanese patients treated with the hypofractionated schedule is acceptable. Especially, radiation dermatitis by the hypofractionated schedule is milder than that by the conventional schedule. (author)

  18. Hypofractionated stereotactic radiotherapy combined with topotecan in recurrent malignant glioma

    International Nuclear Information System (INIS)

    Wurm, Reinhard E.; Kuczer, David A.; Schlenger, Lorenz; Matnjani, Gesa; Scheffler, Dirk; Cosgrove, Vivian P.; Ahlswede, Julia; Woiciechowsky, Christian; Budach, Volker

    2006-01-01

    Purpose: To assess hypofractionated stereotactic radiotherapy (H-SRT) with concurrent topotecan in patients with recurrent malignant glioma. Methods and Materials: Between February 1998 and December 2001, 25 patients with recurrent malignant glioma were treated in a phase I-II study (8 females and 17 males; median age, 45 years; range, 11-66 years; median Karnofsky performance status, 80%, range, 50-100%; median Mini Mental Standard Examination score, 25 points; range, 10-30 points). Of the 25 patients, 20% had World Health Organization Grade III and 80% World Health Organization Grade IV glioma. All patients had been treated previously by external beam radiotherapy with 54.4 Gy in 34 fractions twice daily, at least 6 h apart, within 3.5 weeks or 60 Gy in 30 fractions within 6 weeks. In addition, 84% had already received at least one chemotherapy regimen for recurrence. The median H-SRT dose at the 80% isodose was 25 Gy, and the maximal dose was 30 Gy delivered in five to six fractions on consecutive days. Topotecan (1.1 mg/m 2 /d) was given as a continuous i.v. infusion during H-SRT. Depending on the toxicity and compliance, patients received an additional 48 topotecan courses. Results: For all patients, the actuarial median progression-free survival was 10.5 months (range, 1.4-47.8 months), the median functional survival was 12.6 months (range, 1.6-49.5 months), and the median overall survival was 14.5 months (range, 3-56.4 months). Twelve percent of patients developed presumed adverse radiation effects (Radiation Therapy Oncology Group Grade 2). According to the Common Toxicity Criteria, version 2.0, no topotecan-related Grade 4 toxicity was noted. Grade 3 neutropenia was documented after 14 and Grade 3 thrombopenia after 12 courses. Conclusion: H-SRT with topotecan is feasible and well-tolerated in patients with recurrent high-grade glioma and results in similar survival compared with other repeat treatment modalities

  19. A Prospective Cohort Study of Gated Stereotactic Liver Radiation Therapy Using Continuous Internal Electromagnetic Motion Monitoring

    DEFF Research Database (Denmark)

    Worm, Esben S; Høyer, Morten; Hansen, Rune

    2018-01-01

    PURPOSE: Intrafraction motion can compromise the treatment accuracy in liver stereotactic body radiation therapy (SBRT). Respiratory gating can improve treatment delivery; however, gating based on external motion surrogates is inaccurate. The present study reports the use of Calypso-based internal...... electromagnetic motion monitoring for gated liver SBRT. METHODS AND MATERIALS: Fifteen patients were included in a study of 3-fraction respiratory gated liver SBRT guided by 3 implanted electromagnetic transponders. The planning target volume was created by a 5-mm axial and 7-mm (n = 12) or 10-mm (n = 3...

  20. Hypofractionated stereotactic radiation therapy in three to five fractions for vestibular schwannoma

    International Nuclear Information System (INIS)

    Morimoto, Masahiro; Yoshioka, Yasuo; Kotsuma, Tadayuki

    2013-01-01

    The objective of this study was to retrospectively examine the outcomes of hypofractionated stereotactic radiation therapy in three to five fractions for vestibular schwannomas. Twenty-five patients with 26 vestibular schwannomas were treated with hypofractionated stereotactic radiation therapy using a CyberKnife. The vestibular schwannomas of 5 patients were associated with type II neurofibromatosis. The median follow-up time was 80 months (range: 6-167); the median planning target volume was 2.6 cm 3 (0.3-15.4); and the median prescribed dose (≥D90) was 21 Gy in three fractions (18-25 Gy in three to five fractions). Progression was defined as ≥2 mm 3-dimensional post-treatment tumor enlargement excluding transient expansion. Progression or any death was counted as an event in progression-free survival rates, whereas only progression was counted in progression-free rates. The 7-year progression-free survival and progression-free rates were 78 and 95%, respectively. Late adverse events (≥3 months) with grades based on Common Terminology Criteria for Adverse Events, v4.03 were observed in 6 patients: Grade 3 hydrocephalus in one patient, Grade 2 facial nerve disorders in two and Grade 1-2 tinnitus in three. In total, 12 out of 25 patients maintained pure tone averages ≤50 dB before hypofractionated stereotactic radiation therapy, and 6 of these 12 patients (50%) maintained pure tone averages at this level at the final audiometric follow-up after hypofractionated stereotactic radiation therapy. However, gradient deterioration of pure tone average was observed in 11 of these 12 patients. The mean pure tone averages before hypofractionated stereotactic radiation therapy and at the final follow-up for the aforementioned 12 patients were 29.8 and 57.1 dB, respectively. Treating vestibular schwannomas with hypofractionated stereotactic radiation therapy in three to five fractions may prevent tumor progression with tolerable toxicity. However, gradient

  1. Hypofractionated stereotactic radiation therapy in three to five fractions for vestibular schwannoma

    Energy Technology Data Exchange (ETDEWEB)

    Morimoto, Masahiro; Yoshioka, Yasuo [Osaka Univ., Graduate School of Medicine, Suita, Osaka (Japan); Kotsuma, Tadayuki [Kinki-chuo Chest Medical Center, Sakai, Osaka (Japan); others, and

    2013-08-15

    The objective of this study was to retrospectively examine the outcomes of hypofractionated stereotactic radiation therapy in three to five fractions for vestibular schwannomas. Twenty-five patients with 26 vestibular schwannomas were treated with hypofractionated stereotactic radiation therapy using a CyberKnife. The vestibular schwannomas of 5 patients were associated with type II neurofibromatosis. The median follow-up time was 80 months (range: 6-167); the median planning target volume was 2.6 cm{sup 3} (0.3-15.4); and the median prescribed dose ({>=}D90) was 21 Gy in three fractions (18-25 Gy in three to five fractions). Progression was defined as {>=}2 mm 3-dimensional post-treatment tumor enlargement excluding transient expansion. Progression or any death was counted as an event in progression-free survival rates, whereas only progression was counted in progression-free rates. The 7-year progression-free survival and progression-free rates were 78 and 95%, respectively. Late adverse events ({>=}3 months) with grades based on Common Terminology Criteria for Adverse Events, v4.03 were observed in 6 patients: Grade 3 hydrocephalus in one patient, Grade 2 facial nerve disorders in two and Grade 1-2 tinnitus in three. In total, 12 out of 25 patients maintained pure tone averages {<=}50 dB before hypofractionated stereotactic radiation therapy, and 6 of these 12 patients (50%) maintained pure tone averages at this level at the final audiometric follow-up after hypofractionated stereotactic radiation therapy. However, gradient deterioration of pure tone average was observed in 11 of these 12 patients. The mean pure tone averages before hypofractionated stereotactic radiation therapy and at the final follow-up for the aforementioned 12 patients were 29.8 and 57.1 dB, respectively. Treating vestibular schwannomas with hypofractionated stereotactic radiation therapy in three to five fractions may prevent tumor progression with tolerable toxicity. However, gradient

  2. Non-enhanced ECG-gated respiratory-triggered 3-D steady-state free-precession MR angiography with slab-selective inversion: initial experience in visualisation of renal arteries in free-breathing children without renal artery abnormality

    International Nuclear Information System (INIS)

    Klee, Dirk; Lanzman, Rotem Shlomo; Blondin, Dirk; Antoch, Gerald; Schaper, Joerg; Schmitt, Peter; Oh, Jun; Salgin, Burak; Mayatepek, Ertan

    2012-01-01

    ECG-gated non-enhanced balanced steady-state free precession (bSSFP) MR angiography requires neither breath-holding nor administration of contrast material. To investigate the image quality of free-breathing ECG-gated non-enhanced bSSFP MR angiography of renal arteries in children. Fourteen boys and seven girls (mean age, 9.7 years; range, 7 weeks-17 years) with no history of renovascular disease were included. MRI was performed at 1.5 T. Subjective image quality of axial and coronal maximum-intensity-projection reconstructions of four segments (I, aorta and renal artery ostium; II, main renal artery; III, segmental branches; IV, intrarenal vessels) was evaluated using a 4-point scale (4 = excellent, 3 = good, 2 = acceptable, 1 = non-diagnostic). Image quality was excellent for segments I (mean ± SD, 3.9 ± 0.3) and II (4.0 ± 0.1), good for segment III (3.4 ± 0.9) and acceptable for segment IV (2.3 ± 1.1). Mean image quality did not differ between sedated and non-sedated children. bSSFP MR angiography enables visualisation of renal arteries in children. (orig.)

  3. Improving the Spatial Alignment in PET/CT Using Amplitude-Based Respiration-Gated PET and Respiration-Triggered CT

    NARCIS (Netherlands)

    Vos, C.S. van der; Grootjans, W.; Osborne, D.R.; Meeuwis, A.P.; Hamill, J.J.; Acuff, S.; Geus-Oei, L.F. de; Visser, E.P.

    2015-01-01

    Respiratory motion during PET can cause inaccuracies in the quantification of radiotracer uptake, which negatively affects PET-guided radiotherapy planning. Quantitative accuracy can be improved by respiratory gating. However, additional miscalculation of standardized uptake value (SUV) in PET

  4. Hypofractionated Stereotactic Radiosurgery in a Large Bilateral Thalamic and Basal Ganglia Arteriovenous Malformation

    Directory of Open Access Journals (Sweden)

    Janet Lee

    2013-01-01

    Full Text Available Purpose. Arteriovenous malformations (AVMs in the basal ganglia and thalamus have a more aggressive natural history with a higher morbidity and mortality than AVMs in other locations. Optimal treatment—complete obliteration without new neurological deficits—is often challenging. We present a patient with a large bilateral basal ganglia and thalamic AVM successfully treated with hypofractionated stereotactic radiosurgery (HFSRS with intensity modulated radiotherapy (IMRT. Methods. The patient was treated with hypofractionated stereotactic radiosurgery to 30 Gy at margin in 5 fractions of 9 static fields with a minimultileaf collimator and intensity modulated radiotherapy. Results. At 10 months following treatment, digital subtraction angiography showed complete obliteration of the AVM. Conclusions. Large bilateral thalamic and basal ganglia AVMs can be successfully treated with complete obliteration by HFSRS with IMRT with relatively limited toxicity. Appropriate caution is recommended.

  5. Role of the Technical Aspects of Hypofractionated Radiation Therapy Treatment of Prostate Cancer: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Clemente, Stefania, E-mail: clemente_stefania@libero.it [Istituto di Ricovero e Cura a Carattere Scientifico Centro di Riferimento Oncologico della Basilicata Rionero in Vulture, Potenza (Italy); Nigro, Roberta [Azienda Sanitaria Locale Rieti, Roma (Italy); Oliviero, Caterina [Istituto di Ricovero e Cura a Carattere Scientifico Centro di Riferimento Oncologico della Basilicata Rionero in Vulture, Potenza (Italy); Marchioni, Chiara [Azienda Sanitaria Locale Rieti, Roma (Italy); Esposito, Marco [Azienda Sanitaria, Firenze (Italy); Giglioli, Francesca Romana [Azienda Ospedaliera Città della Salute e della Scienza di Torino, Torino (Italy); Mancosu, Pietro [Humanitas Clinical and Research Hospital, Rozzano, Milano (Italy); Marino, Carmelo [Humanitas Centro Catanese di Oncologia, Catania (Italy); Russo, Serenella [Azienda Sanitaria, Firenze (Italy); Stasi, Michele [Azienda Ospedaliera Ordine Mauriziano di Torino, Torino (Italy); Strigari, Lidia [Istituto Nazionale Tumori Regina Elena, Roma (Italy); Veronese, Ivan [Universita' degli Studi di Milano, Milano (Italy); Landoni, Valeria [Istituto Nazionale Tumori Regina Elena, Roma (Italy)

    2015-01-01

    The increasing use of moderate (<35 fractions) and extreme (<5 fractions) hypofractionated radiation therapy in prostate cancer is yielding favorable results, both in terms of maintained biochemical response and toxicity. Several hypofractionation (HF) schemes for the treatment of prostate cancer are available, although there is considerable variability in the techniques used to manage intra-/interfraction motion and deliver radiation doses. We performed a review of the published studies on HF regimens as a topic of interest for the Stereotactic Ablative Radiotherapy working group, which is part of the Italian Association of Medical Physics. Aspects of organ motion management (imaging for contouring, target volume definition, and rectum/bladder preparation) and treatment delivery (prostate localization, image guided radiation therapy strategy and frequency) were evaluated and categorized to assess outcome relative to disease control and toxicity. Despite the heterogeneity of the data, some interesting trends that emerged from the review might be useful in identifying an optimum HF strategy.

  6. Salvage Treatment With Hypofractionated Radiotherapy in Patients With Recurrent Small Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Bae, Sun Hyun; Park, Hee Chul; Lim, Do Hoon; Lee, Jung Ae; Gwak, Geum Yeon; Choi, Moon Seok; Lee, Joon Hyoek; Koh, Kwang Cheol; Paik, Seung Woon; Yoo, Byung Chul

    2012-01-01

    Purpose: To investigate the rates of tumor response and local control in patients with recurrent small hepatocellular carcinoma (HCC) treated with hypofractionated radiotherapy (RT) as a salvage treatment and to evaluate treatment-related toxicities. Methods and Materials: Between 2006 and 2009, a total of 20 patients with recurrent small HCC were treated with hypofractionated RT after the failure of previous treatment. The eligibility criteria for hypofractionated RT were as follows: 1) HCC less than 5 cm, 2) HCC not adjacent to critical organs, 3) HCC without portal vein tumor thrombosis, and 4) less than 15% of normal liver volume that would be irradiated with 50% of prescribed dose. The RT dose was 50 Gy in 10 fractions. The tumor response was determined by CT scans performed 3 months after the end of RT. Results: The median follow-up period after RT was 22 months. The overall survival rates at 1 and 2 years were 100% and 87.9%, respectively. Complete response (CR) was achieved in seven of 20 lesions (35%) evaluated by CT scans performed 3 months after the end of RT. In-field local control was achieved in 85% of patients. Fourteen patients (70%) developed intra-hepatic metastases. Six patients developed grade 1 nausea or anorexia during RT, and two patients had progression of ascites after RT. There was no grade 3 or greater treatment-related toxicities. Conclusions: The current study showed a favorable outcome with respect to hypofractionated RT for small HCC. Partial liver irradiation with 50 Gy in 10 fractions is considered tolerable without severe complications.

  7. Salvage Treatment With Hypofractionated Radiotherapy in Patients With Recurrent Small Hepatocellular Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Sun Hyun [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Park, Hee Chul, E-mail: rophc@skku.edu [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Lim, Do Hoon; Lee, Jung Ae [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Gwak, Geum Yeon; Choi, Moon Seok; Lee, Joon Hyoek; Koh, Kwang Cheol; Paik, Seung Woon; Yoo, Byung Chul [Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2012-03-15

    Purpose: To investigate the rates of tumor response and local control in patients with recurrent small hepatocellular carcinoma (HCC) treated with hypofractionated radiotherapy (RT) as a salvage treatment and to evaluate treatment-related toxicities. Methods and Materials: Between 2006 and 2009, a total of 20 patients with recurrent small HCC were treated with hypofractionated RT after the failure of previous treatment. The eligibility criteria for hypofractionated RT were as follows: 1) HCC less than 5 cm, 2) HCC not adjacent to critical organs, 3) HCC without portal vein tumor thrombosis, and 4) less than 15% of normal liver volume that would be irradiated with 50% of prescribed dose. The RT dose was 50 Gy in 10 fractions. The tumor response was determined by CT scans performed 3 months after the end of RT. Results: The median follow-up period after RT was 22 months. The overall survival rates at 1 and 2 years were 100% and 87.9%, respectively. Complete response (CR) was achieved in seven of 20 lesions (35%) evaluated by CT scans performed 3 months after the end of RT. In-field local control was achieved in 85% of patients. Fourteen patients (70%) developed intra-hepatic metastases. Six patients developed grade 1 nausea or anorexia during RT, and two patients had progression of ascites after RT. There was no grade 3 or greater treatment-related toxicities. Conclusions: The current study showed a favorable outcome with respect to hypofractionated RT for small HCC. Partial liver irradiation with 50 Gy in 10 fractions is considered tolerable without severe complications.

  8. Hypofractionated Intensity-Modulated Radiotherapy for Carcinoma of the Prostate: Analysis of Toxicity

    International Nuclear Information System (INIS)

    Coote, Joanna H.; Wylie, James P.; Cowan, Richard A.; Logue, John P.; Swindell, Ric; Livsey, Jacqueline E.

    2009-01-01

    Purpose: Dose escalation for prostate cancer improves biological control but with a significant increase in late toxicity. Recent estimates of low α/β ratio for prostate cancer suggest that hypofractionation may result in biological advantage. Intensity-modulated radiotherapy (IMRT) should enable dose escalation to the prostate while reducing toxicity to local organs. We report late toxicity data of a hypofractionated IMRT regime. Methods and Materials: Eligible men had T2-3N0M0 adenocarcinoma prostate, and either Gleason score ≥ 7 or prostate-specific antigen 20-50 ng/L. Patients received 57-60 Gy to prostate in 19-20 fractions using five-field IMRT. All received hormonal therapy for 3 months before radiotherapy to a maximum of 6 months. Toxicity was assessed 2 years postradiotherapy using the RTOG criteria, LENT/SOMA, and UCLA prostate index assessment tools. Results: Acute toxicity was favorable with no RTOG Grade 3 or 4 toxicity. At 2 years, there was 4% Grade 2 bowel and 4.25% Grade 2 bladder toxicity. There was no Grade 3 or 4 bowel toxicity; one patient developed Grade 3 bladder toxicity. UCLA data showed a slight improvement in urinary function at 2 years compared with pretreatment. LENT/SOMA assessments demonstrated general worsening of bowel function at 2 years. Patients receiving 60 Gy were more likely to develop problems with bowel function than those receiving 57 Gy. Conclusions: These data demonstrate that hypofractionated radiotherapy using IMRT for prostate cancer is well tolerated with minimal late toxicity at 2 years posttreatment. Ongoing studies are looking at the efficacy of hypofractionated regimes with respect to biological control.

  9. Extracranial Facial Nerve Schwannoma Treated by Hypo-fractionated CyberKnife Radiosurgery

    OpenAIRE

    Sasaki, Ayaka; Miyazaki, Shinichiro; Hori, Tomokatsu

    2016-01-01

    Facial nerve schwannoma is a rare intracranial tumor. Treatment for this benign tumor has been controversial. Here, we report a case of extracranial facial nerve schwannoma treated successfully by hypo-fractionated CyberKnife (Accuray, Sunnyvale, CA) radiosurgery?and discuss the efficacy of this treatment. A 34-year-old female noticed a swelling in her right mastoid process. The lesion enlarged over a seven-month period, and she experienced facial spasm on the right side. She was diagnosed wi...

  10. Image Guided Hypofractionated Radiotherapy by Helical Tomotherapy for Prostate Carcinoma: Toxicity and Impact on Nadir PSA

    Directory of Open Access Journals (Sweden)

    Salvina Barra

    2014-01-01

    Full Text Available Aim. To evaluate the toxicity of a hypofractionated schedule for primary radiotherapy (RT of prostate cancer as well as the value of the nadir PSA (nPSA and time to nadir PSA (tnPSA as surrogate efficacy of treatment. Material and Methods. Eighty patients underwent hypofractionated schedule by Helical Tomotherapy (HT. A dose of 70.2 Gy was administered in 27 daily fractions of 2.6 Gy. Acute and late toxicities were graded on the RTOG/EORTC scales. The nPSA and the tnPSA for patients treated with exclusive RT were compared to an equal cohort of 20 patients treated with conventional fractionation and standard conformal radiotherapy. Results. Most of patients (83% did not develop acute gastrointestinal (GI toxicity and 50% did not present genitourinary (GU toxicity. After a median follow-up of 36 months only grade 1 of GU and GI was reported in 6 and 3 patients as late toxicity. Average tnPSA was 30 months. The median value of nPSA after exclusive RT with HT was 0.28 ng/mL and was significantly lower than the median nPSA (0.67 ng/mL of the conventionally treated cohort (P=0.02. Conclusions. Hypofractionated RT schedule with HT for prostate cancer treatment reports very low toxicity and reaches a low level of nPSA that might correlate with good outcomes.

  11. Respiratory mechanics

    CERN Document Server

    Wilson, Theodore A

    2016-01-01

    This book thoroughly covers each subfield of respiratory mechanics: pulmonary mechanics, the respiratory pump, and flow. It presents the current understanding of the field and serves as a guide to the scientific literature from the golden age of respiratory mechanics, 1960 - 2010. Specific topics covered include the contributions of surface tension and tissue forces to lung recoil, the gravitational deformation of the lung, and the interdependence forces that act on pulmonary airways and blood vessels. The geometry and kinematics of the ribs is also covered in detail, as well as the respiratory action of the external and internal intercostal muscles, the mechanics of the diaphragm, and the quantitative compartmental models of the chest wall is also described. Additionally, flow in the airways is covered thoroughly, including the wave-speed and viscous expiratory flow-limiting mechanisms; convection, diffusion and the stationary front; and the distribution of ventilation. This is an ideal book for respiratory ...

  12. Geographic Disparity in the Use of Hypofractionated Radiation Therapy Among Elderly Women Undergoing Breast Conservation for Invasive Breast Cancer

    International Nuclear Information System (INIS)

    Gillespie, Erin F.; Matsuno, Rayna K.; Xu, Beibei; Triplett, Daniel P.; Hwang, Lindsay; Boero, Isabel J.; Einck, John P.; Yashar, Catheryn; Murphy, James D.

    2016-01-01

    Purpose: To evaluate geographic heterogeneity in the delivery of hypofractionated radiation therapy (RT) for breast cancer among Medicare beneficiaries across the United States. Methods and Materials: We identified 190,193 patients from the Centers for Medicare and Medicaid Services Chronic Conditions Warehouse. The study included patients aged >65 years diagnosed with invasive breast cancer treated with breast conservation surgery followed by radiation diagnosed between 2000 and 2012. We analyzed data by hospital referral region based on patient residency ZIP code. The proportion of women who received hypofractionated RT within each region was analyzed over the study period. Multivariable logistic regression models identified predictors of hypofractionated RT. Results: Over the entire study period we found substantial geographic heterogeneity in the use of hypofractionated RT. The proportion of women receiving hypofractionated breast RT in individual hospital referral regions varied from 0% to 61%. We found no correlation between the use of hypofractionated RT and urban/rural setting or general geographic region. The proportion of hypofractionated RT increased in regions with higher density of radiation oncologists, as well as lower total Medicare reimbursements. Conclusions: This study demonstrates substantial geographic heterogeneity in the use of hypofractionated RT among elderly women with invasive breast cancer treated with lumpectomy in the United States. This heterogeneity persists despite clinical data from multiple randomized trials proving efficacy and safety compared with standard fractionation, and highlights possible inefficiency in health care delivery.

  13. Geographic Disparity in the Use of Hypofractionated Radiation Therapy Among Elderly Women Undergoing Breast Conservation for Invasive Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, Erin F.; Matsuno, Rayna K.; Xu, Beibei; Triplett, Daniel P.; Hwang, Lindsay; Boero, Isabel J.; Einck, John P.; Yashar, Catheryn; Murphy, James D., E-mail: j2murphy@ucsd.edu

    2016-10-01

    Purpose: To evaluate geographic heterogeneity in the delivery of hypofractionated radiation therapy (RT) for breast cancer among Medicare beneficiaries across the United States. Methods and Materials: We identified 190,193 patients from the Centers for Medicare and Medicaid Services Chronic Conditions Warehouse. The study included patients aged >65 years diagnosed with invasive breast cancer treated with breast conservation surgery followed by radiation diagnosed between 2000 and 2012. We analyzed data by hospital referral region based on patient residency ZIP code. The proportion of women who received hypofractionated RT within each region was analyzed over the study period. Multivariable logistic regression models identified predictors of hypofractionated RT. Results: Over the entire study period we found substantial geographic heterogeneity in the use of hypofractionated RT. The proportion of women receiving hypofractionated breast RT in individual hospital referral regions varied from 0% to 61%. We found no correlation between the use of hypofractionated RT and urban/rural setting or general geographic region. The proportion of hypofractionated RT increased in regions with higher density of radiation oncologists, as well as lower total Medicare reimbursements. Conclusions: This study demonstrates substantial geographic heterogeneity in the use of hypofractionated RT among elderly women with invasive breast cancer treated with lumpectomy in the United States. This heterogeneity persists despite clinical data from multiple randomized trials proving efficacy and safety compared with standard fractionation, and highlights possible inefficiency in health care delivery.

  14. WE-F-304-03: Optic Nerve/Chiasm Hypofractionated SRS/SRT Dose Tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Milano, M. [University of Rochester Medical Center (United States)

    2015-06-15

    Stereotactic Body Radiation Therapy (SBRT) was introduced clinically more than twenty years ago, and many subsequent publications have reported safety and efficacy data. The AAPM Working Group on Biological Effects of Hypofractionated Radiotherapy/SBRT (WGSBRT) extracted published treatment outcomes data from extensive literature searches to summarize and construct tumor control probability (TCP) and normal tissue complication probability (NTCP) models for six anatomical regions: Cranial, Head and Neck, Thoracic, Abdominal, Pelvic, and Spinal. In this session, we present the WGSBRT’s work for cranial sites, and recurrent head and neck cancer. From literature-based data and associated models, guidelines to aid with safe and effective hypofractionated radiotherapy treatment are being determined. Further, the ability of existing and proposed radiobiological models to fit these data is considered as to the ability to distinguish between the linear-quadratic and alternative radiobiological models such as secondary cell death from vascular damage, immunogenic, or bystander effects. Where appropriate, specific model parameters are estimated. As described in “The lessons of QUANTEC,” (1), lack of adequate reporting standards continues to limit the amount of useful quantitative information that can be extracted from peer-reviewed publications. Recommendations regarding reporting standards are considered, to enable such reviews to achieve more complete characterization of clinical outcomes. 1 Jackson A, Marks LB, Bentzen SM, Eisbruch A, Yorke ED, Ten Haken RK, Constine LS, Deasy JO. The lessons of QUANTEC: recommendations for reporting and gathering data on dose-volume dependencies of treatment outcome. Int J Radiat Oncol Biol Phys. 2010 Mar 1;76(3 Suppl):S155–60. Learning Objectives: Describe the techniques, types of cancer and dose schedules used in treating recurrent H&N cancers with SBRT List the radiobiological models that compete with the linear-quadratic model

  15. WE-F-304-00: Outcomes of Hypofractionated Treatments - Results of the WGSBRT

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    Stereotactic Body Radiation Therapy (SBRT) was introduced clinically more than twenty years ago, and many subsequent publications have reported safety and efficacy data. The AAPM Working Group on Biological Effects of Hypofractionated Radiotherapy/SBRT (WGSBRT) extracted published treatment outcomes data from extensive literature searches to summarize and construct tumor control probability (TCP) and normal tissue complication probability (NTCP) models for six anatomical regions: Cranial, Head and Neck, Thoracic, Abdominal, Pelvic, and Spinal. In this session, we present the WGSBRT’s work for cranial sites, and recurrent head and neck cancer. From literature-based data and associated models, guidelines to aid with safe and effective hypofractionated radiotherapy treatment are being determined. Further, the ability of existing and proposed radiobiological models to fit these data is considered as to the ability to distinguish between the linear-quadratic and alternative radiobiological models such as secondary cell death from vascular damage, immunogenic, or bystander effects. Where appropriate, specific model parameters are estimated. As described in “The lessons of QUANTEC,” (1), lack of adequate reporting standards continues to limit the amount of useful quantitative information that can be extracted from peer-reviewed publications. Recommendations regarding reporting standards are considered, to enable such reviews to achieve more complete characterization of clinical outcomes. 1 Jackson A, Marks LB, Bentzen SM, Eisbruch A, Yorke ED, Ten Haken RK, Constine LS, Deasy JO. The lessons of QUANTEC: recommendations for reporting and gathering data on dose-volume dependencies of treatment outcome. Int J Radiat Oncol Biol Phys. 2010 Mar 1;76(3 Suppl):S155–60. Learning Objectives: Describe the techniques, types of cancer and dose schedules used in treating recurrent H&N cancers with SBRT List the radiobiological models that compete with the linear-quadratic model

  16. Clinical Usefulness of Implanted Fiducial Markers for Hypofractionated Radiotherapy of Prostate Cancer

    International Nuclear Information System (INIS)

    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

    2011-01-01

    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 difference among the

  17. WE-F-304-00: Outcomes of Hypofractionated Treatments - Results of the WGSBRT

    International Nuclear Information System (INIS)

    2015-01-01

    Stereotactic Body Radiation Therapy (SBRT) was introduced clinically more than twenty years ago, and many subsequent publications have reported safety and efficacy data. The AAPM Working Group on Biological Effects of Hypofractionated Radiotherapy/SBRT (WGSBRT) extracted published treatment outcomes data from extensive literature searches to summarize and construct tumor control probability (TCP) and normal tissue complication probability (NTCP) models for six anatomical regions: Cranial, Head and Neck, Thoracic, Abdominal, Pelvic, and Spinal. In this session, we present the WGSBRT’s work for cranial sites, and recurrent head and neck cancer. From literature-based data and associated models, guidelines to aid with safe and effective hypofractionated radiotherapy treatment are being determined. Further, the ability of existing and proposed radiobiological models to fit these data is considered as to the ability to distinguish between the linear-quadratic and alternative radiobiological models such as secondary cell death from vascular damage, immunogenic, or bystander effects. Where appropriate, specific model parameters are estimated. As described in “The lessons of QUANTEC,” (1), lack of adequate reporting standards continues to limit the amount of useful quantitative information that can be extracted from peer-reviewed publications. Recommendations regarding reporting standards are considered, to enable such reviews to achieve more complete characterization of clinical outcomes. 1 Jackson A, Marks LB, Bentzen SM, Eisbruch A, Yorke ED, Ten Haken RK, Constine LS, Deasy JO. The lessons of QUANTEC: recommendations for reporting and gathering data on dose-volume dependencies of treatment outcome. Int J Radiat Oncol Biol Phys. 2010 Mar 1;76(3 Suppl):S155–60. Learning Objectives: Describe the techniques, types of cancer and dose schedules used in treating recurrent H&N cancers with SBRT List the radiobiological models that compete with the linear-quadratic model

  18. WE-F-304-03: Optic Nerve/Chiasm Hypofractionated SRS/SRT Dose Tolerance

    International Nuclear Information System (INIS)

    Milano, M.

    2015-01-01

    Stereotactic Body Radiation Therapy (SBRT) was introduced clinically more than twenty years ago, and many subsequent publications have reported safety and efficacy data. The AAPM Working Group on Biological Effects of Hypofractionated Radiotherapy/SBRT (WGSBRT) extracted published treatment outcomes data from extensive literature searches to summarize and construct tumor control probability (TCP) and normal tissue complication probability (NTCP) models for six anatomical regions: Cranial, Head and Neck, Thoracic, Abdominal, Pelvic, and Spinal. In this session, we present the WGSBRT’s work for cranial sites, and recurrent head and neck cancer. From literature-based data and associated models, guidelines to aid with safe and effective hypofractionated radiotherapy treatment are being determined. Further, the ability of existing and proposed radiobiological models to fit these data is considered as to the ability to distinguish between the linear-quadratic and alternative radiobiological models such as secondary cell death from vascular damage, immunogenic, or bystander effects. Where appropriate, specific model parameters are estimated. As described in “The lessons of QUANTEC,” (1), lack of adequate reporting standards continues to limit the amount of useful quantitative information that can be extracted from peer-reviewed publications. Recommendations regarding reporting standards are considered, to enable such reviews to achieve more complete characterization of clinical outcomes. 1 Jackson A, Marks LB, Bentzen SM, Eisbruch A, Yorke ED, Ten Haken RK, Constine LS, Deasy JO. The lessons of QUANTEC: recommendations for reporting and gathering data on dose-volume dependencies of treatment outcome. Int J Radiat Oncol Biol Phys. 2010 Mar 1;76(3 Suppl):S155–60. Learning Objectives: Describe the techniques, types of cancer and dose schedules used in treating recurrent H&N cancers with SBRT List the radiobiological models that compete with the linear-quadratic model

  19. Image Guided Hypofractionated Postprostatectomy Intensity Modulated Radiation Therapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Stephen L.; Patel, Pretesh; Song, Haijun [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Freedland, Stephen J. [Surgery Section, Durham Veterans Administration, and Division of Urology, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California (United States); Bynum, Sigrun; Oh, Daniel; Palta, Manisha; Yoo, David; Oleson, James [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Salama, Joseph K., E-mail: joseph.salama@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)

    2016-03-01

    Purpose: Hypofractionated radiation therapy (RT) has promising long-term biochemical relapse-free survival (bRFS) with comparable toxicity for definitive treatment of prostate cancer. However, data reporting outcomes after adjuvant and salvage postprostatectomy hypofractionated RT are sparse. Therefore, we report the toxicity and clinical outcomes after postprostatectomy hypofractionated RT. Methods and Materials: From a prospectively maintained database, men receiving image guided hypofractionated intensity modulated RT (HIMRT) with 2.5-Gy fractions constituted our study population. Androgen deprivation therapy was used at the discretion of the radiation oncologist. Acute toxicities were graded according to the Common Terminology Criteria for Adverse Events version 4.0. Late toxicities were scored using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scale. Biochemical recurrence was defined as an increase of 0.1 in prostate-specific antigen (PSA) from posttreatment nadir or an increase in PSA despite treatment. The Kaplan-Meier method was used for the time-to-event outcomes. Results: Between April 2008 and April 2012, 56 men received postoperative HIMRT. The median follow-up time was 48 months (range, 21-67 months). Thirty percent had pre-RT PSA <0.1; the median pre-RT detectable PSA was 0.32 ng/mL. The median RT dose was 65 Gy (range, 57.5-65 Gy). Ten patients received neoadjuvant and concurrent hormone therapy. Posttreatment acute urinary toxicity was limited. There was no acute grade 3 toxicity. Late genitourinary (GU) toxicity of any grade was noted in 52% of patients, 40% of whom had pre-RT urinary incontinence. The 4-year actuarial rate of late grade 3 GU toxicity (exclusively gross hematuria) was 28% (95% confidence interval [CI], 16%-41%). Most grade 3 GU toxicity resolved; only 7% had persistent grade ≥3 toxicity at the last follow-up visit. Fourteen patients experienced biochemical recurrence at a

  20. Choosing Wisely? Patterns and Correlates of the Use of Hypofractionated Whole-Breast Radiation Therapy in the State of Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Jagsi, Reshma, E-mail: rjagsi@med.umich.edu [University of Michigan, Ann Arbor, Michigan (United States); Griffith, Kent A. [University of Michigan, Ann Arbor, Michigan (United States); Heimburger, David [Munson Medical Center, Traverse City, Michigan (United States); Walker, Eleanor M. [Henry Ford Hospital, Detroit, Michigan (United States); Grills, Inga S. [Beaumont Health System, Royal Oak, Michigan (United States); Boike, Thomas [McLaren Northern Michigan, Petoskey, Michigan (United States); Feng, Mary; Moran, Jean M.; Hayman, James; Pierce, Lori J. [University of Michigan, Ann Arbor, Michigan (United States)

    2014-12-01

    Purpose: Given evidence from randomized trials that have established the non-inferiority of more convenient and less costly courses of hypofractionated radiotherapy to the whole breast in selected breast cancer patients who receive lumpectomy, we sought to investigate the use of hypofractionated radiation therapy and factors associated with its use in a consortium of radiation oncology practices in Michigan. We sought to determine the extent to which variation in use occurs at the physician or practice level versus the extent to which use reflects individualization based on potentially relevant patient characteristics (such as habitus, age, chemotherapy receipt, or laterality). Methods and Materials: We evaluated associations between receipt of hypofractionated radiation therapy and various patient, provider, and practice characteristics in a multilevel model. Results: Of 1477 patients who received lumpectomy and whole-breast radiation therapy and were registered by the Michigan Radiation Oncology Quality Consortium (MROQC) from October 2011 to December 2013, 913 had T1-2, N0 breast cancer. Of these 913, 283 (31%) received hypofractionated radiation therapy. Among the 13 practices, hypofractionated radiation therapy use ranged from 2% to 80%. On multilevel analysis, 51% of the variation in the rate of hypofractionation was attributable to the practice level, 21% to the provider level, and 28% to the patient level. On multivariable analysis, hypofractionation was more likely in patients who were older (odds ratio [OR] 2.16 for age ≥50 years, P=.007), less likely in those with larger body habitus (OR 0.52 if separation between tangent entry and exit ≥25 cm, P=.002), and more likely without chemotherapy receipt (OR 3.82, P<.001). Hypofractionation use was not higher in the last 6 months analyzed: 79 of 252 (31%) from June 2013 to December 2013 and 204 of 661 (31%) from October 2011 to May 2013 (P=.9). Conclusions: Hypofractionated regimens of whole

  1. Acute and Late Toxicity in a Randomized Trial of Conventional Versus Hypofractionated Three-Dimensional Conformal Radiotherapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Arcangeli, Giorgio; Fowler, Jack; Gomellini, Sara; Arcangeli, Stefano; Saracino, Biancamaria; Petrongari, Maria Grazia; Benassi, Marcello; Strigari, Lidia

    2011-01-01

    Purpose: To compare the toxicity between hypofractionation vs. conventional fractionation schedules in patients with high-risk prostate cancer. Methods and Materials: Between January 2003 and December 2007, 168 patients were randomized to receive either hypofractionated (62 Gy in 20 fractions within 5 weeks, 4 fractions/wk) or conventionally fractionated (80 Gy in 40 fractions within 8 weeks) three-dimensional conformal radiotherapy to the prostate and seminal vesicles. All patients had undergone a 9-month course of total androgen deprivation, with radiotherapy starting 2 months after initiation of the total androgen deprivation. Results: The median follow-up was 32 and 35 months in the hypofractionation and conventional fractionation arms, respectively. For the patients developing acute toxicity, no difference between the two fractionation groups was found in either severity or duration of gastrointestinal or genitourinary toxicity. Also, no difference was found in the incidence and severity of late gastrointestinal and genitourinary toxicity between the two treatment schedules, with a 3-year rate of Grade 2 or greater toxicity of 17% and 16% for the hypofractionation arm and 14% and 11% for the conventional fractionation arm, respectively. A statistically significant correlation between acute and late gastrointestinal toxicity was found only in the conventional fractionation group. Conclusion: Our findings suggest that the hypofractionation regimen used in our study is safe, with only a slight, nonsignificant increase in tolerable and temporary acute toxicity compared with the conventional fractionation schedule. The severity and frequency of late complications was equivalent between the two treatment groups.

  2. Quantum gate decomposition algorithms.

    Energy Technology Data Exchange (ETDEWEB)

    Slepoy, Alexander

    2006-07-01

    Quantum computing algorithms can be conveniently expressed in a format of a quantum logical circuits. Such circuits consist of sequential coupled operations, termed ''quantum gates'', or quantum analogs of bits called qubits. We review a recently proposed method [1] for constructing general ''quantum gates'' operating on an qubits, as composed of a sequence of generic elementary ''gates''.

  3. Respiratory synchronization for lung tumors exploration by positon emission tomography

    International Nuclear Information System (INIS)

    Grotus, Nicolas

    2009-01-01

    Positron Emission Tomography (PET) is a medical imaging technique that requires several minutes of acquisition to get an image. PET images are thus severely affected by the respiratory motion of the patient, which introduces a blur in the images. Techniques consisting in gating the PET acquisition as a function of the patient respiration exist and reduce the respiratory blur in the PET images. However, these techniques increase the noise in the reconstructed images. The aim of this work was to propose a method for respiratory motion compensation that would not enhance the noise in the PET images, without increasing the acquisition duration nor estimating the deformation field associated with the respiratory motion. We proposed 2 original spatio-temporal (4D) reconstruction algorithms of gated PET images. These 2 methods take advantage of the temporal correlation between the images corresponding to the different breathing phases. The performances of these techniques were evaluated and compared to classic approaches using phantom data and simulated data. The results showed that the 4D reconstructions increase the signal-to-noise ratio compared to the classic reconstructions while maintaining the reduction of the respiratory blur. For a fixed acquisition duration, the 4D reconstructions can thus yield gated images that are almost free of respiratory blur and of the same quality in terms of noise level as the ones obtained without respiratory gating. The clinical feasibility of the proposed techniques was also demonstrated. (author) [fr

  4. Signatures of Mechanosensitive Gating.

    Science.gov (United States)

    Morris, Richard G

    2017-01-10

    The question of how mechanically gated membrane channels open and close is notoriously difficult to address, especially if the protein structure is not available. This perspective highlights the relevance of micropipette-aspirated single-particle tracking-used to obtain a channel's diffusion coefficient, D, as a function of applied membrane tension, σ-as an indirect assay for determining functional behavior in mechanosensitive channels. While ensuring that the protein remains integral to the membrane, such methods can be used to identify not only the gating mechanism of a protein, but also associated physical moduli, such as torsional and dilational rigidity, which correspond to the protein's effective shape change. As an example, three distinct D-versus-σ "signatures" are calculated, corresponding to gating by dilation, gating by tilt, and gating by a combination of both dilation and tilt. Both advantages and disadvantages of the approach are discussed. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  5. Prostate hypofractionated radiation therapy with injection of hyaluronic acid: acute toxicities in a phase 2 study.

    Science.gov (United States)

    Chapet, Olivier; Decullier, Evelyne; Bin, Sylvie; Faix, Antoine; Ruffion, Alain; Jalade, Patrice; Fenoglietto, Pascal; Udrescu, Corina; Enachescu, Ciprian; Azria, David

    2015-03-15

    Hypofractionated radiation therapy (RT) in prostate cancer can be developed only if the risk of rectal toxicity is controlled. In a multicenter phase 2 trial, hypofractionated irradiation was combined with an injection of hyaluronic acid (HA) to preserve the rectal wall. Tolerance of the injection and acute toxicity rates are reported. The study was designed to assess late grade 2 toxicity rates. The results described here correspond to the secondary objectives. Acute toxicity was defined as occurring during RT or within 3 months after RT and graded according to the Common Terminology Criteria for Adverse Events version 4.0. HA tolerance was evaluated with a visual analog scale during the injection and 30 minutes after injection and then by use of the Common Terminology Criteria at each visit. From 2010 to 2012, 36 patients with low-risk to intermediate-risk prostate cancer were included. The HA injection induced a mean pain score of 4.6/10 ± 2.3. Thirty minutes after the injection, 2 patients still reported pain (2/10 and 3/10), which persisted after the intervention. Thirty-three patients experienced at least 1 acute genitourinary toxicity and 20 patients at least 1 acute gastrointestinal toxicity. Grade 2 toxicities were reported for 19 patients with urinary obstruction, frequency, or both and for 1 patient with proctitis. No grade 3 or 4 toxicities were reported. At the 3-month visit, 4 patients described grade 2 obstruction or frequency, and no patients had any grade 2 gastrointestinal toxicities. The injection of HA makes it possible to deliver hypofractionated irradiation over 4 weeks with a dose per fraction of > 3 Gy, with limited acute rectal toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Prostate Hypofractionated Radiation Therapy With Injection of Hyaluronic Acid: Acute Toxicities in a Phase 2 Study

    International Nuclear Information System (INIS)

    Chapet, Olivier; Decullier, Evelyne; Bin, Sylvie; Faix, Antoine; Ruffion, Alain; Jalade, Patrice; Fenoglietto, Pascal; Udrescu, Corina; Enachescu, Ciprian; Azria, David

    2015-01-01

    Purpose: Hypofractionated radiation therapy (RT) in prostate cancer can be developed only if the risk of rectal toxicity is controlled. In a multicenter phase 2 trial, hypofractionated irradiation was combined with an injection of hyaluronic acid (HA) to preserve the rectal wall. Tolerance of the injection and acute toxicity rates are reported. Methods and Materials: The study was designed to assess late grade 2 toxicity rates. The results described here correspond to the secondary objectives. Acute toxicity was defined as occurring during RT or within 3 months after RT and graded according to the Common Terminology Criteria for Adverse Events version 4.0. HA tolerance was evaluated with a visual analog scale during the injection and 30 minutes after injection and then by use of the Common Terminology Criteria at each visit. Results: From 2010 to 2012, 36 patients with low-risk to intermediate-risk prostate cancer were included. The HA injection induced a mean pain score of 4.6/10 ± 2.3. Thirty minutes after the injection, 2 patients still reported pain (2/10 and 3/10), which persisted after the intervention. Thirty-three patients experienced at least 1 acute genitourinary toxicity and 20 patients at least 1 acute gastrointestinal toxicity. Grade 2 toxicities were reported for 19 patients with urinary obstruction, frequency, or both and for 1 patient with proctitis. No grade 3 or 4 toxicities were reported. At the 3-month visit, 4 patients described grade 2 obstruction or frequency, and no patients had any grade 2 gastrointestinal toxicities. Conclusions: The injection of HA makes it possible to deliver hypofractionated irradiation over 4 weeks with a dose per fraction of > 3 Gy, with limited acute rectal toxicity

  7. Prostate Hypofractionated Radiation Therapy With Injection of Hyaluronic Acid: Acute Toxicities in a Phase 2 Study

    Energy Technology Data Exchange (ETDEWEB)

    Chapet, Olivier, E-mail: olivier.chapet@chu-lyon.fr [Department of Radiation Oncology, Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Pierre Benite (France); EMR3738, Université Lyon 1, Lyon (France); Decullier, Evelyne; Bin, Sylvie [Pole Information Médicale Evaluation Recherche, Hospices Civils de Lyon, Lyon (France); Université Lyon 1, Lyon (France); EA SIS, Université de Lyon, Lyon (France); Faix, Antoine [Department of Urology, Clinique Beausoleil, Montpellier (France); Ruffion, Alain [Université Lyon 1, Lyon (France); Department of Urology, Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Pierre Benite (France); Jalade, Patrice [Department of Medical Physics, Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Pierre Benite (France); Fenoglietto, Pascal [Department of Radiation Oncology and Physics, Institut du Cancer de Montpellier, Montpellier (France); Udrescu, Corina; Enachescu, Ciprian [Department of Radiation Oncology, Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Pierre Benite (France); Azria, David [Department of Radiation Oncology and Physics, Institut du Cancer de Montpellier, Montpellier (France)

    2015-03-15

    Purpose: Hypofractionated radiation therapy (RT) in prostate cancer can be developed only if the risk of rectal toxicity is controlled. In a multicenter phase 2 trial, hypofractionated irradiation was combined with an injection of hyaluronic acid (HA) to preserve the rectal wall. Tolerance of the injection and acute toxicity rates are reported. Methods and Materials: The study was designed to assess late grade 2 toxicity rates. The results described here correspond to the secondary objectives. Acute toxicity was defined as occurring during RT or within 3 months after RT and graded according to the Common Terminology Criteria for Adverse Events version 4.0. HA tolerance was evaluated with a visual analog scale during the injection and 30 minutes after injection and then by use of the Common Terminology Criteria at each visit. Results: From 2010 to 2012, 36 patients with low-risk to intermediate-risk prostate cancer were included. The HA injection induced a mean pain score of 4.6/10 ± 2.3. Thirty minutes after the injection, 2 patients still reported pain (2/10 and 3/10), which persisted after the intervention. Thirty-three patients experienced at least 1 acute genitourinary toxicity and 20 patients at least 1 acute gastrointestinal toxicity. Grade 2 toxicities were reported for 19 patients with urinary obstruction, frequency, or both and for 1 patient with proctitis. No grade 3 or 4 toxicities were reported. At the 3-month visit, 4 patients described grade 2 obstruction or frequency, and no patients had any grade 2 gastrointestinal toxicities. Conclusions: The injection of HA makes it possible to deliver hypofractionated irradiation over 4 weeks with a dose per fraction of > 3 Gy, with limited acute rectal toxicity.

  8. Hypofractionated electron-beam radiation therapy for keloids. Retrospective study of 568 cases with 834 lesions

    International Nuclear Information System (INIS)

    Shen Jie; Lian Xin; Sun Yuliang

    2015-01-01

    We aimed to analyze the outcomes of hypofractionated high-energy electron beam radiotherapy for the treatment of keloids. From February 1998 to January 2012, 568 patients with a total of 834 keloids underwent radiotherapy: 826 lesions with postoperative radiotherapy, and 36 with skin-grafting. Lesion size was >5 cm in 335 keloids. An electron-beam of 6 or 7 MeV was used, with a total dose of 18 Gy (two fractions with a 1-week interval) covering the lesion with a 1-cm margin. The time between surgery and radiotherapy was 24–48 h. Skin-grafted patients underwent radiotherapy 10–15 days after the operation. The median follow-up was 40 months (range: 12–160 months). The local control rate was 88.25% (736/834). The relapse rate was 9.59% (80/834), and the time to relapse was 6–28 months (median: 12 months). Univariate analyses showed that gender, age, keloid size, keloid site, skin grafting, and operation-to-irradiation interval influenced the local control rate. Multivariate analysis showed that the relapse rate was correlated with gender (P = 0.048), age (P < 0.01), operation-to-irradiation interval (P < 0.01), keloid site (P < 0.01), surgical method (P = 0.04) and keloid size (P < 0.02). Adverse effects were observed in 9.83% (82/834). No radiation-induced cancers were observed. Hypofractionated high-energy electron beam radiotherapy for keloids yielded excellent outcomes, especially in cases without skin grafting. Early postoperative radiotherapy with limited hypofractionation could be a good choice for keloid treatment. (author)

  9. Dosimetric Feasibility of Hypofractionated Proton Radiotherapy for Neoadjuvant Pancreatic Cancer Treatment

    International Nuclear Information System (INIS)

    Kozak, Kevin R.; Kachnic, Lisa A.; Adams, Judith C; Crowley, Elizabeth M.; Alexander, Brian M.; Mamon, Harvey J.; Fernandez-Del Castillo, Carlos; Ryan, David P.; DeLaney, Thomas F.; Hong, Theodore S.

    2007-01-01

    Purpose: To evaluate tumor and normal tissue dosimetry of a 5 cobalt gray equivalent (CGE) x 5 fraction proton radiotherapy schedule, before initiating a clinical trial of neoadjuvant, short-course proton radiotherapy for pancreatic adenocarcinoma. Methods and Materials: The first 9 pancreatic cancer patients treated with neoadjuvant intensity-modulated radiotherapy (1.8 Gy x 28) at the Massachusetts General Hospital had treatment plans generated using a 5 CGE x 5 fraction proton regimen. To facilitate dosimetric comparisons, clinical target volumes and normal tissue volumes were held constant. Plans were optimized for target volume coverage and normal tissue sparing. Results: Hypofractionated proton and conventionally fractionated intensity-modulated radiotherapy plans both provided acceptable target volume coverage and dose homogeneity. Improved dose conformality provided by the hypofractionated proton regimen resulted in significant sparing of kidneys, liver, and small bowel, evidenced by significant reductions in the mean doses, expressed as percentage prescribed dose, to these structures. Kidney and liver sparing was most evident in low-dose regions (≤20% prescribed dose for both kidneys and ≤60% prescribed dose for liver). Improvements in small-bowel dosimetry were observed in high- and low-dose regions. Mean stomach and duodenum doses, expressed as percentage prescribed dose, were similar for the two techniques. Conclusions: A proton radiotherapy schedule consisting of 5 fractions of 5 CGE as part of neoadjuvant therapy for adenocarcinoma of the pancreas seems dosimetrically feasible, providing excellent target volume coverage, dose homogeneity, and normal tissue sparing. Hypofractionated proton radiotherapy in this setting merits Phase I clinical trial investigation

  10. Respiratory monitoring with an acceleration sensor

    International Nuclear Information System (INIS)

    Ono, Tomohiro; Takegawa, Hideki; Ageishi, Tatsuya; Takashina, Masaaki; Numasaki, Hodaka; Matsumoto, Masao; Teshima, Teruki

    2011-01-01

    Respiratory gating radiotherapy is used to irradiate a local area and to reduce normal tissue toxicity. There are certain methods for the detection of tumor motions, for example, using internal markers or an external respiration signal. However, because some of these respiratory monitoring systems require special or expensive equipment, respiratory monitoring can usually be performed only in limited facilities. In this study, the feasibility of using an acceleration sensor for respiratory monitoring was evaluated. The respiratory motion was represented by means of a platform and measured five times with the iPod touch (registered) at 3, 4 and 5 s periods of five breathing cycles. For these three periods of the reference waveform, the absolute means ± standard deviation (SD) of displacement were 0.45 ± 0.34 mm, 0.33 ± 0.24 mm and 0.31 ± 0.23 mm, respectively. On the other hand, the corresponding absolute means ± SD for the periods were 0.04 ± 0.09 s, 0.04 ± 0.02 s and 0.06 ± 0.04 s. The accuracy of respiratory monitoring using the acceleration sensor was satisfactory in terms of the absolute means ± SD. Using the iPod touch (registered) for respiratory monitoring does not need special equipment and makes respiratory monitoring easier. For these reasons, this system is a viable alternative to other respiratory monitoring systems.

  11. Norm- and hypo-fractionated radiotherapy is capable of activating human dendritic cells.

    Science.gov (United States)

    Kulzer, Lorenz; Rubner, Yvonne; Deloch, Lisa; Allgäuer, Andrea; Frey, Benjamin; Fietkau, Rainer; Dörrie, Jan; Schaft, Niels; Gaipl, Udo S

    2014-10-01

    Despite the transient immunosuppressive properties of local radiotherapy (RT), this classical treatment modality of solid tumors is capable of inducing immunostimulatory forms of tumor-cell death. The resulting 'immunotoxicity' in the tumor, but not in healthy tissues, may finally lead to immune-mediated destruction of the tumor. However, little is known about the best irradiation scheme in this setting. This study examines the immunological effects of differently irradiated human colorectal tumor cells on human monocyte-derived dendritic cells (DC). Human SW480 tumor cells were irradiated with a norm-fractionation scheme (5 × 2 Gy), a hypo-fractionated protocol (3 × 5 Gy), and with a high single irradiation dose (radiosurgery; 1 × 15 Gy). Subsequently, human immature DC (iDC) were co-incubated with supernatants (SN) of these differently treated tumor cells. Afterwards, DC were analyzed regarding the expression of maturation markers, the release of cytokines, and the potential to stimulate CD4(+) T-cells. The co-incubation of iDC with SN of tumor cells exposed to norm- or hypo-fractionated RT resulted in a significantly increased secretion of the immune activating cytokines IL-12p70, IL-8, IL-6, and TNFα, compared to iDC co-incubated with SN of tumor cells that received a high single irradiation dose or were not irradiated. In addition, DC-maturation markers CD80, CD83, and CD25 were also exclusively elevated after co-incubation with the SN of fractionated irradiated tumor cells. Furthermore, the SN of tumor cells that were irradiated with norm- or hypo-fractionated RT triggered iDC to stimulate CD4(+) T-cells not only in an allogenic, but also in an antigen-specific manner like mature DC. Collectively, these results demonstrate that norm- and hypo-fractionated RT induces a fast human colorectal tumor-cell death with immunogenic potential that can trigger DC maturation and activation in vitro. Such findings may contribute to the improvement of

  12. Title: hypofractionated postoperative irradiation for cutaneous melanoma of the head and neck

    International Nuclear Information System (INIS)

    Omizo, Russ T.; Marquez, Carol M.; Vetto, John T.

    1996-01-01

    Purpose/Objective: To evaluate the efficacy and tolerance of hypofractionated postoperative irradiation in patients with head and neck cutaneous melanoma at high risk for local-regional recurrence. Methods and Materials: Between May 1990 to February 1995, 26 patients with cutaneous melanoma of the head and neck were evaluated in the Department of Radiation Oncology at the Oregon Health Sciences University for elective postoperative hypofractionated irradiation. Twelve patients were excluded from analysis because of simultaneous distant metastatic disease. The remaining 14 patients were at high risk for local-regional recurrence because of either nodal disease, T3 or greater disease, recurrent disease following previous treatment or a combination of the above. TNM stage distribution for patients treated at initial presentation was: T4aN1-2, T4aN0-3, T3bN0-1, T3aN0-1, T2N1-1 and TxN1-1. The initial TNM stage for patients presenting with recurrent disease was: T4aN2-a, T4aN1-1, T1N0-1, T2N0-1 and TxN1-1. All patients received adjuvant irradiation to at least 2 echelons of draining lymph nodes +/- the primary site. The median elapsed time between surgery and irradiation was 4 weeks. Hypofractionated irradiation consisted of 600 cGy fractions given twice weekly for 5 fractions. Twelve patients were treated with electrons of appropriate energy, 1 with photons and 1 with photons and electrons. Median duration of treatment was 15 days. Results: With a median follow-up of 41 months, 2 patients have failed local-regionally and at distant sites and one patient has failed with distant disease only. The actuarial 5 year local-regional control rate is 86% with a standard error of 9%. The actuarial 5 year survival is 60% with a standard error of 16%. Acute side effects were self limiting and were most commonly erythema and mucositis. Chronic side effects were mild and included fibrosis, telangiectasias and xerostomia. Conclusions: Adjuvant hypofractionated irradiation provides

  13. Effect of image-guided hypofractionated stereotactic radiotherapy on peripheral non-small-cell lung cancer

    Directory of Open Access Journals (Sweden)

    Wang SW

    2016-08-01

    Full Text Available Shu-wen Wang,1 Juan Ren,1 Yan-li Yan,2 Chao-fan Xue,2 Li Tan,2 Xiao-wei Ma2 1Department of Radiotherapy, First Affiliated Hospital of Xian Jiaotong University, 2Medical School of Xian Jiaotong University, Xi’an, Shaanxi, People’s Republic of China Abstract: The objective of this study was to compare the effects of image-guided hypofractionated radiotherapy and conventional fractionated radiotherapy on non-small-cell lung cancer (NSCLC. Fifty stage- and age-matched cases with NSCLC were randomly divided into two groups (A and B. There were 23 cases in group A and 27 cases in group B. Image-guided radiotherapy (IGRT and stereotactic radiotherapy were conjugately applied to the patients in group A. Group A patients underwent hypofractionated radiotherapy (6–8 Gy/time three times per week, with a total dose of 64–66 Gy; group B received conventional fractionated radiotherapy, with a total dose of 68–70 Gy five times per week. In group A, 1-year and 2-year local failure survival rate and 1-year local failure-free survival rate were significantly higher than in group B (P<0.05. The local failure rate (P<0.05 and distant metastasis rate (P>0.05 were lower in group A than in group B. The overall survival rate of group A was significantly higher than that of group B (P=0.03, and the survival rate at 1 year was 87% vs 63%, (P<0.05. The median survival time of group A was longer than that of group B. There was no significant difference in the incidence of complications between the two groups (P>0.05. Compared with conventional fractionated radiation therapy, image-guided hypofractionated stereotactic radiotherapy in NSCLC received better treatment efficacy and showed good tolerability. Keywords: non-small-cell lung cancer, hypofractionated radiotherapy, stereotactic radiotherapy, segmentation, intensity-modulated radiotherapy, image-guided radiation therapy technology

  14. Whole-Pelvic Nodal Radiation Therapy in the Context of Hypofractionation for High-Risk Prostate Cancer Patients: A Step Forward

    International Nuclear Information System (INIS)

    Kaidar-Person, Orit; Roach, Mack; Créhange, Gilles

    2013-01-01

    Given the low α/β ratio of prostate cancer, prostate hypofractionation has been tested through numerous clinical studies. There is a growing body of literature suggesting that with high conformal radiation therapy and even with more sophisticated radiation techniques, such as high-dose-rate brachytherapy or image-guided intensity modulated radiation therapy, morbidity associated with shortening overall treatment time with higher doses per fraction remains low when compared with protracted conventional radiation therapy to the prostate only. In high-risk prostate cancer patients, there is accumulating evidence that either dose escalation to the prostate or hypofractionation may improve outcome. Nevertheless, selected patients who have a high risk of lymph node involvement may benefit from whole-pelvic radiation therapy (WPRT). Although combining WPRT with hypofractionated prostate radiation therapy is feasible, it remains investigational. By combining modern advances in radiation oncology (high-dose-rate prostate brachytherapy, intensity modulated radiation therapy with an improved image guidance for soft-tissue sparing), it is hypothesized that WPRT could take advantage of recent results from hypofractionation trials. Moreover, the results from hypofractionation trials raise questions as to whether hypofractionation to pelvic lymph nodes with a high risk of occult involvement might improve the outcomes in WPRT. Although investigational, this review discusses the challenging idea of WPRT in the context of hypofractionation for patients with high-risk prostate cancer

  15. Whole-Pelvic Nodal Radiation Therapy in the Context of Hypofractionation for High-Risk Prostate Cancer Patients: A Step Forward

    Energy Technology Data Exchange (ETDEWEB)

    Kaidar-Person, Orit [Division of Oncology, Rambam Health Care Campus, Haifa (Israel); Roach, Mack [Department of Radiation Oncology, University of California, San Francisco, San Francisco, California (United States); Créhange, Gilles, E-mail: gcrehange@cgfl.fr [Department of Radiation Oncology, Georges-François Leclerc Cancer Center, Dijon (France)

    2013-07-15

    Given the low α/β ratio of prostate cancer, prostate hypofractionation has been tested through numerous clinical studies. There is a growing body of literature suggesting that with high conformal radiation therapy and even with more sophisticated radiation techniques, such as high-dose-rate brachytherapy or image-guided intensity modulated radiation therapy, morbidity associated with shortening overall treatment time with higher doses per fraction remains low when compared with protracted conventional radiation therapy to the prostate only. In high-risk prostate cancer patients, there is accumulating evidence that either dose escalation to the prostate or hypofractionation may improve outcome. Nevertheless, selected patients who have a high risk of lymph node involvement may benefit from whole-pelvic radiation therapy (WPRT). Although combining WPRT with hypofractionated prostate radiation therapy is feasible, it remains investigational. By combining modern advances in radiation oncology (high-dose-rate prostate brachytherapy, intensity modulated radiation therapy with an improved image guidance for soft-tissue sparing), it is hypothesized that WPRT could take advantage of recent results from hypofractionation trials. Moreover, the results from hypofractionation trials raise questions as to whether hypofractionation to pelvic lymph nodes with a high risk of occult involvement might improve the outcomes in WPRT. Although investigational, this review discusses the challenging idea of WPRT in the context of hypofractionation for patients with high-risk prostate cancer.

  16. Management of respiratory motion in radiation oncology

    International Nuclear Information System (INIS)

    Vedam, Subrahmanya Sastry

    2003-01-01

    Respiration affects the instantaneous position of almost all thoracic and abdominal structures (lung, breast, liver, pancreas, etc.), posing significant problems in the radiotherapy of tumors located at these sites. The diaphragm, for example, has been shown to move approximately 1.5 cm in the superior-inferior direction during normal breathing. During radiotherapy, margin expansion around the tumor, based on an estimate of the expected range of tumor motion, is commonly employed to ensure adequate dose coverage. Such a margin estimate may or may not encompass the 'current' extent of motion exhibited by the tumor, resulting in either a higher dose to the surrounding normal tissue or a cold spot in the tumor volume, leading to poor prognosis. Accounting for respiratory motion by active management during radiotherapy can, however, potentiate a reduction in the amount of high dose to normal tissue. Active management of respiratory motion forms the primary theme of this dissertation. Among the various techniques available to manage respiratory motion, our research focused on respiratory gated and respiration synchronized radiotherapy, with an external marker to monitor respiratory motion. Multiple session recordings of diaphragm and external marker motion revealed a consistent linear relationship, validating the use of external marker motion as a 'surrogate' for diaphragm motion. The predictability of diaphragm motion based on such external marker motion both within and between treatment sessions was also determined to be of the order of 0.1 cm. Gating during exhalation was found to be more reproducible than gating during inhalation. Although, a reduction in the 'gate' width achieved a modest reduction in the margins added around the tumor further reduction was limited by setup error. A motion phantom study of the potential gains from respiratory gating indicated margin reduction of 0.2-1.1 cm while employing gating. In addition, gating also improved the quality of

  17. MO-FG-BRA-03: A Novel Method for Characterizing Gating Response Time in Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, R; McCabe, B; Belcher, A; Jenson, P [The University of Chicago, Chicago, IL (United States); Smith, B [University Illinois at Chicago, Orland Park, IL (United States); Aydogan, B [The University of Chicago, Chicago, IL (United States); University Illinois at Chicago, Orland Park, IL (United States)

    2016-06-15

    Purpose: Low temporal latency between a gating ON/OFF signal and the LINAC beam ON/OFF during respiratory gating is critical for patient safety. Current film based methods to assess gating response have poor temporal resolution and are highly qualitative. We describe a novel method to precisely measure gating lag times at high temporal resolutions and use it to characterize the temporal response of several gating systems. Methods: A respiratory gating simulator with an oscillating platform was modified to include a linear potentiometer for position measurement. A photon diode was placed at linear accelerator isocenter for beam output measurement. The output signals of the potentiometer and diode were recorded simultaneously at 2500 Hz (0.4 millisecond (ms) sampling interval) with an analogue-to-digital converter (ADC). The techniques was used on three commercial respiratory gating systems. The ON and OFF of the beam signal were located and compared to the expected gating window for both phase and position based gating and the temporal lag times extracted using a polynomial fit method. Results: A Varian RPM system with a monoscopic IR camera was measured to have mean beam ON and OFF lag times of 98.2 ms and 89.6 ms, respectively. A Varian RPM system with a stereoscopic IR camera was measured to have mean beam ON and OFF lag times of 86.0 ms and 44.0 ms, respectively. A Calypso magnetic fiducial tracking system was measured to have mean beam ON and OFF lag times of 209.0 ms and 60.0 ms, respectively. Conclusions: A novel method allowed for quantitative determination of gating timing accuracy for several clinically used gating systems. All gating systems met the 100 ms TG-142 criteria for mean beam OFF times. For beam ON response, the Calypso system exceeded the recommended response time.

  18. Optical XOR gate

    Science.gov (United States)

    Vawter, G. Allen

    2013-11-12

    An optical XOR gate is formed as a photonic integrated circuit (PIC) from two sets of optical waveguide devices on a substrate, with each set of the optical waveguide devices including an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  19. A Dosimetric Comparison between Conventional Fractionated and Hypofractionated Image-guided Radiation Therapies for Localized Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Ming Li

    2016-01-01

    Conclusions: To deliver the hypofractionated radiotherapy in prostate cancer, VMAT significantly increased PTV D95% dose and decreased the dose of radiation delivered to adjacent normal tissues comparing to 7-field, step-and-shoot IMRT. Daily online image-guidance and better management of bladder and rectum could make a more precise treatment delivery.

  20. Image-Guided Hypofractionated Radiotherapy in Low-Risk Prostate Cancer Patients

    Directory of Open Access Journals (Sweden)

    Maurizio Valeriani

    2014-01-01

    Full Text Available Aim. To evaluate efficacy and toxicity of image-guided hypofractionated radiotherapy (HFRT in the treatment of low-risk prostate cancer. Outcomes and toxicities of this series of patients were compared to another group of 32 low-risk patients treated with conventional fractionation (CFRT. Methods. Fifty-nine patients with low-risk prostate cancer were analysed. Total dose for the prostate and proximal seminal vesicles was 60 Gy delivered in 20 fractions. Results. The median follow-up was 30 months. The actuarial 4-year overall survival, biochemical free survival, and disease specific survival were 100%, 97.4%, and 97.4%, respectively. Acute grade 1-2 gastrointestinal (GI and genitourinary (GU toxicity rates were 11.9% and 40.7%, respectively. Grade 1 GI and GU late toxicity rates were 8.5% and 13.6%, respectively. No grade ≥2 late toxicities were recorded. Acute grade 2-3 GU toxicity resulted significantly lower (P=0.04 in HFRT group compared to the CFRT group. The cumulative 4-year incidence of grade 1-2 GU toxicity was significantly higher (P<0.001 for HFRT patients. Conclusions. Our study demonstrated that hypofractionated regimen provided excellent biochemical control in favorable risk prostate cancer patients. The incidence of GI and GU toxicity was low. However, HFRT presented higher cumulative incidence of low-grade late GU toxicity than CFRT.

  1. Outcomes in Newly Diagnosed Elderly Glioblastoma Patients after Concomitant Temozolomide Administration and Hypofractionated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ludovic T. [Neurology Department, CHU Hautepierre, rue Molière, Strasbourg 67000 (France); Touch, Socheat [Radiation Oncology University Department, Paul Strauss Center, 3, rue de la Porte de l’Hôpital, BP 42, Strasbourg cedex 67065 (France); Radiation Oncology Department, Soviet-Khmer Friendship Hospital, Pnom-Pehn 12400 (Cambodia); Nehme-Schuster, Hélène [Oncology Geriatric Department, Paul Strauss Center, 3, rue de la Porte de l’Hôpital, BP 42, Strasbourg cedex 67065 (France); Antoni, Delphine [Radiation Oncology University Department, Paul Strauss Center, 3, rue de la Porte de l’Hôpital, BP 42, Strasbourg cedex 67065 (France); Eav, Sokha [Radiation Oncology Department, Soviet-Khmer Friendship Hospital, Pnom-Pehn 12400 (Cambodia); Clavier, Jean-Baptiste; Bauer, Nicolas; Vigneron, Céline [Radiation Oncology University Department, Paul Strauss Center, 3, rue de la Porte de l’Hôpital, BP 42, Strasbourg cedex 67065 (France); Schott, Roland [Oncology Department, Paul Strauss Center, 3, rue de la Porte de l’Hôpital, BP 42, Strasbourg cedex 67065 (France); Kehrli, Pierre [Neurosurgery Department, CHU Hautepierre, rue Molière, Strasbourg 67000 (France); Noël, Georges, E-mail: gnoel@strasbourg.unicancer.fr [Radiation Oncology University Department, Paul Strauss Center, 3, rue de la Porte de l’Hôpital, BP 42, Strasbourg cedex 67065 (France); Laboratoire EA 3430, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg 67000 (France)

    2013-09-24

    This study aimed to analyze the treatment and outcomes of older glioblastoma patients. Forty-four patients older than 70 years of age were referred to the Paul Strauss Center for chemotherapy and radiotherapy. The median age was 75.5 years old (range: 70–84), and the patients included 18 females and 26 males. The median Karnofsky index (KI) was 70%. The Charlson indices varied from 4 to 6. All of the patients underwent surgery. O{sub 6}-methylguanine–DNA methyltransferase (MGMT) methylation status was determined in 25 patients. All of the patients received radiation therapy. Thirty-eight patients adhered to a hypofractionated radiation therapy schedule and six patients to a normofractionated schedule. Neoadjuvant, concomitant and adjuvant chemotherapy regimens were administered to 12, 35 and 20 patients, respectively. At the time of this analysis, 41 patients had died. The median time to relapse was 6.7 months. Twenty-nine patients relapsed, and 10 patients received chemotherapy upon relapse. The median overall survival (OS) was 7.2 months and the one- and two-year OS rates were 32% and 12%, respectively. In a multivariate analysis, only the Karnofsky index was a prognostic factor. Hypofractionated radiotherapy and chemotherapy with temozolomide are feasible and acceptably tolerated in older patients. However, relevant prognostic factors are needed to optimize treatment proposals.

  2. Outcome analysis of 300 prostate cancer patients treated with neoadjuvant androgen deprivation and hypofractionated radiotherapy

    International Nuclear Information System (INIS)

    Higgins, Geoffrey S.; McLaren, Duncan B.; Kerr, Gillian R.; Elliott, Tony; Howard, Grahame

    2006-01-01

    Purpose: Neoadjuvant androgen deprivation and radical radiotherapy is an established treatment for localized prostate carcinoma. This study sought to analyze the outcomes of patients treated with relatively low-dose hypofractionated radiotherapy. Methods and Materials: Three hundred patients with T1-T3 prostate cancer were treated between 1996 and 2001. Patients were prescribed 3 months of neoadjuvant androgen deprivation before receiving 5250 cGy in 20 fractions. Patients' case notes and the oncology database were used to retrospectively assess outcomes. Median follow-up was 58 months. Results: Patients presented with prostate cancer with poorer prognostic indicators than that reported in other series. At 5 years, the actuarial cause-specific survival rate was 83.2% and the prostate-specific antigen (PSA) relapse rate was 57.3%. Metastatic disease had developed in 23.4% of patients. PSA relapse continued to occur 5 years from treatment in all prognostic groups. Independent prognostic factors for relapse included treatment near the start of the study period, neoadjuvant oral anti-androgen monotherapy rather than neoadjuvant luteinizing hormone releasing hormone therapy, and diagnosis through transurethral resection of the prostate rather than transrectal ultrasound. Conclusion: This is the largest reported series of patients treated with neoadjuvant androgen deprivation and hypofractionated radiotherapy in the United Kingdom. Neoadjuvant hormonal therapy did not appear to adequately compensate for the relatively low effective radiation dose used

  3. On the importance of prompt oxygen changes for hypofractionated radiation treatments

    International Nuclear Information System (INIS)

    Kissick, Michael; Campos, David; Van der Kogel, Albert; Kimple, Randall

    2013-01-01

    This discussion is motivated by observations of prompt oxygen changes occurring prior to a significant number of cancer cells dying (permanently stopping their metabolic activity) from therapeutic agents like large doses of ionizing radiation. Such changes must be from changes in the vasculature that supplies the tissue or from the metabolic changes in the tissue itself. An adapted linear–quadratic treatment is used to estimate the cell survival variation magnitudes from repair and reoxygenation from a two-fraction treatment in which the second fraction would happen prior to significant cell death from the first fraction, in the large fraction limit. It is clear the effects of oxygen changes are likely to be the most significant factor for hypofractionation because of large radiation doses. It is a larger effect than repair. Optimal dose timing should be determined by the peak oxygen timing. A call is made to prioritize near real time measurements of oxygen dynamics in tumors undergoing hypofractionated treatments in order to make these treatments adaptable and patient-specific. (note)

  4. Outcomes in Newly Diagnosed Elderly Glioblastoma Patients after Concomitant Temozolomide Administration and Hypofractionated Radiotherapy

    International Nuclear Information System (INIS)

    Nguyen, Ludovic T.; Touch, Socheat; Nehme-Schuster, Hélène; Antoni, Delphine; Eav, Sokha; Clavier, Jean-Baptiste; Bauer, Nicolas; Vigneron, Céline; Schott, Roland; Kehrli, Pierre; Noël, Georges

    2013-01-01

    This study aimed to analyze the treatment and outcomes of older glioblastoma patients. Forty-four patients older than 70 years of age were referred to the Paul Strauss Center for chemotherapy and radiotherapy. The median age was 75.5 years old (range: 70–84), and the patients included 18 females and 26 males. The median Karnofsky index (KI) was 70%. The Charlson indices varied from 4 to 6. All of the patients underwent surgery. O 6 -methylguanine–DNA methyltransferase (MGMT) methylation status was determined in 25 patients. All of the patients received radiation therapy. Thirty-eight patients adhered to a hypofractionated radiation therapy schedule and six patients to a normofractionated schedule. Neoadjuvant, concomitant and adjuvant chemotherapy regimens were administered to 12, 35 and 20 patients, respectively. At the time of this analysis, 41 patients had died. The median time to relapse was 6.7 months. Twenty-nine patients relapsed, and 10 patients received chemotherapy upon relapse. The median overall survival (OS) was 7.2 months and the one- and two-year OS rates were 32% and 12%, respectively. In a multivariate analysis, only the Karnofsky index was a prognostic factor. Hypofractionated radiotherapy and chemotherapy with temozolomide are feasible and acceptably tolerated in older patients. However, relevant prognostic factors are needed to optimize treatment proposals

  5. Respiratory Home Health Care

    Science.gov (United States)

    ... Us Home > Healthy Living > Living With Lung Disease > Respiratory Home Health Care Font: Aerosol Delivery Oxygen Resources ... Teenagers Living With Lung Disease Articles written by Respiratory Experts Respiratory Home Health Care Respiratory care at ...

  6. COMPARISON OF HYPOFRACTIONATED RADIATION THERAPY VERSUS CONVENTIONAL RADIATION THERAPY IN POST MASTECTOMY BREAST CANCER

    Directory of Open Access Journals (Sweden)

    Abhilash

    2016-03-01

    Full Text Available INTRODUCTION Breast cancer is the most common cancer in women worldwide and a leading cause of cancer death in females and accounts for 1.8 million new cases and approximately 0.5 million deaths annually. Patients who present with locally advanced breast cancer (LABC require multidisciplinary team approach that incorporates diagnostic imaging, surgery, chemotherapy and histopathological assessment, including molecular-based studies, radiation, and, if indicated, biologic and hormonal therapies. Hypofractionated radiation therapy following mastectomy has been used in many institutions for several decades and have demonstrated equivalent local control, cosmetic and normal tissues between 50 Gy in 25 fractions and various hypofractionated radiotherapy prescriptions employing 13-16 fractions. Evidence suggests that hypofractionated radiotherapy may also be safe and effective for regional nodal disease. AIMS AND OBJECTIVES To compare the local control and side effects of hypofractionated radiation therapy with conventional radiation therapy in post mastectomy carcinoma breast with stage II and III and to compare the tolerability and compliance of both schedules. MATERIALS AND METHODS The study was conducted on 60 histopathologically proven patients of carcinoma of breast, treated surgically with modified radical mastectomy. Group I patients were given external radiation to chest flap and drainage areas, a dose of 39 Gy/13 fractions/3.1 weeks, a daily dose 3 Gy for 13 fractions in 4 days a week schedule and Group II patients were given external radiation to chest flap and drainage areas, a dose of 50 Gy/25 fractions/5 weeks, to receive a daily dose 2 Gy for 25 fractions in a 5 days a week schedule. RESULTS The median age at presentation in Group I and II was 48 and 50 years respectively. Locoregional control after completion of radiotherapy in Group I vs. Group II was 26/30 (86.7% vs. 27/30 (90% respectively. Acute reactions and their grades in Group

  7. Hypofractionation vs Conventional Radiation Therapy for Newly Diagnosed Diffuse Intrinsic Pontine Glioma: A Matched-Cohort Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Janssens, Geert O., E-mail: g.janssens@rther.umcn.nl [Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Jansen, Marc H. [Pediatric Oncology/Hematology, VU University Medical Center, Amsterdam (Netherlands); Lauwers, Selmer J. [Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Nowak, Peter J. [Department of Radiation Oncology, Erasmus Medical Centre, Rotterdam (Netherlands); Oldenburger, Foppe R. [Department of Radiation Oncology, Academic Medical Centre, Amsterdam (Netherlands); Bouffet, Eric [Department of Hematology/Oncology, The Hospital for Sick Children, University of Toronto, Toronto (Canada); Saran, Frank [Department of Pediatric Oncology, The Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Kamphuis-van Ulzen, Karin [Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Lindert, Erik J. van [Department of Neurosurgery, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Schieving, Jolanda H. [Department of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Boterberg, Tom [Department of Radiation Oncology, Ghent University Hospital, Ghent (Belgium); Kaspers, Gertjan J. [Pediatric Oncology/Hematology, VU University Medical Center, Amsterdam (Netherlands); Span, Paul N.; Kaanders, Johannes H. [Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Gidding, Corrie E. [Department of Pediatric Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Hargrave, Darren [Department of Oncology, Great Ormond Street Hospital, London (United Kingdom)

    2013-02-01

    Purpose: Despite conventional radiation therapy, 54 Gy in single doses of 1.8 Gy (54/1.8 Gy) over 6 weeks, most children with diffuse intrinsic pontine glioma (DIPG) will die within 1 year after diagnosis. To reduce patient burden, we investigated the role of hypofractionation radiation therapy given over 3 to 4 weeks. A 1:1 matched-cohort analysis with conventional radiation therapy was performed to assess response and survival. Methods and Materials: Twenty-seven children, aged 3 to 14, were treated according to 1 of 2 hypofractionation regimens over 3 to 4 weeks (39/3 Gy, n=16 or 44.8/2.8 Gy, n=11). All patients had symptoms for {<=}3 months, {>=}2 signs of the neurologic triad (cranial nerve deficit, ataxia, long tract signs), and characteristic features of DIPG on magnetic resonance imaging. Twenty-seven patients fulfilling the same diagnostic criteria and receiving at least 50/1.8 to 2.0 Gy were eligible for the matched-cohort analysis. Results: With hypofractionation radiation therapy, the overall survival at 6, 9, and 12 months was 74%, 44%, and 22%, respectively. Progression-free survival at 3, 6, and 9 months was 77%, 43%, and 12%, respectively. Temporary discontinuation of steroids was observed in 21 of 27 (78%) patients. No significant difference in median overall survival (9.0 vs 9.4 months; P=.84) and time to progression (5.0 vs 7.6 months; P=.24) was observed between hypofractionation vs conventional radiation therapy, respectively. Conclusions: For patients with newly diagnosed DIPG, a hypofractionation regimen, given over 3 to 4 weeks, offers equal overall survival with less treatment burden compared with a conventional regimen of 6 weeks.

  8. Patient costs associated with external beam radiotherapy treatment for localized prostate cancer: the benefits of hypofractionated over conventionally fractionated radiotherapy.

    Science.gov (United States)

    Sethukavalan, Perakaa; Cheung, Patrick; Tang, Colin I; Quon, Harvey; Morton, Gerard; Nam, Robert; Loblaw, Andrew

    2012-04-01

    To estimate the out-of-pocket costs for patients undergoing external beam radiotherapy (EBRT) for prostate cancer and calculate the patient-related savings of being treated with a 5-fraction versus a standard 39-fraction approach. Seventy patients accrued to the pHART3 (n = 84) study were analyzed for out-of-pocket patient costs as a result of undergoing treatment. All costs are in Canadian dollars. Using the postal code of the patient's residence, the distance between the hospital and patient home was found using Google Maps. The Canada Revenue Agency automobile allowance rate was then applied to determine the cost per kilometer driven. The average cost of travel from the hospital and pHART3 patient's residence was $246 per person after five trips. In a standard fractionation regimen, pHART3 patients would have incurred an average cost of $1921 after 39 visits. The patients receiving hypofractionated radiotherapy would have paid an average of $38 in parking while those receiving conventional treatment would have paid $293. The difference in out-of-pocket costs for the patients receiving a standard versus hypofractionated treatment was $1930. Medium term prospective data shows that hypofractionated radiotherapy is an effective treatment method for localized prostate cancer. Compared to standard EBRT, hypofractionated radiotherapy requires significantly fewer visits. Due to the long distance patients may have to travel to the cancer center and the expense of parking, the short course treatment saves each patient an average of $1900. A randomized study of standard versus hypofractionated accelerated radiotherapy should be conducted to confirm a favorable efficacy and tolerability profile of the shorter fractionation scheme.

  9. The Pattern of Use of Hypofractionated Radiation Therapy for Early-Stage Breast Cancer in New South Wales, Australia, 2008 to 2012

    Energy Technology Data Exchange (ETDEWEB)

    Delaney, Geoff P., E-mail: Geoff.delaney@swsahs.nsw.gov.au [Liverpool Cancer Therapy Centre, Liverpool, New South Wales (Australia); Collaboration for Cancer Outcomes Research and Evaluation, University of New South Wales, Sydney (Australia); Ingham Health and Medical Research Institute, Sydney (Australia); New South Wales Cancer Institute (Australia); Gandhidasan, Senthilkumar [Peter MacCallum Cancer Centre, Melbourne (Australia); Walton, Richard; Terlich, Frances; Baker, Deborah; Currow, David [New South Wales Cancer Institute (Australia)

    2016-10-01

    Purpose: Increasing phase 3 evidence has been published about the safety and efficacy of hypofractionated radiation therapy, in comparison with standard fractionation, in early-stage, node-negative breast cancer. However, uptake of hypofractionation has not been universal. The aim of this study was to investigate the hypofractionation regimen variations in practice across public radiation oncology facilities in New South Wales (NSW). Methods and Materials: Patients with early breast cancer registered in the NSW Clinical Cancer Registry who received radiation therapy for early-stage breast cancer in a publicly funded radiation therapy department between 2008 and 2012 were identified. Data extracted and analyzed included dose and fractionation type, patient age at first fraction, address (for geocoding), year of diagnosis, year of treatment, laterality, and department of treatment. A logistic regression model was used to identify factors associated with fractionation type. Results: Of the 5880 patients fulfilling the study criteria, 3209 patients (55%) received standard fractionation and 2671 patients (45%) received hypofractionation. Overall, the use of hypofractionation increased from 37% in 2008 to 48% in 2012 (range, 7%-94% across departments). Treatment facility and the radiation oncologist prescribing the treatment were the strongest independent predictors of hypofractionation. Weaker associations were also found for age, tumor site laterality, year of treatment, and distance to facility. Conclusions: Hypofractionated regimens of whole breast radiation therapy have been variably administered in the adjuvant setting in NSW despite the publication of long-term trial results and consensus guidelines. Some factors that predict the use of hypofractionation are not based on guideline recommendations, including lower rates of left-sided treatment and increasing distance from a treatment facility.

  10. Hypofractionated radiotherapy for primary or secondary oligometastatic lung cancer using Tomotherapy

    International Nuclear Information System (INIS)

    Chang, Heng-Jui; Ko, Hui-Ling; Lee, Cheng-Yen; Wu, Ren-Hong; Yeh, Yu-Wung; Jiang, Jiunn-Song; Kao, Shang-Jyh; Chi, Kwan-Hwa

    2012-01-01

    To retrospectively review the outcome of patients with primary or secondary oligometastatic lung cancer, treated with hypofractionated Tomotherapy. Between April 2007 and June 2011, a total of 33 patients with oligometastatic intrapulmonary lesions underwent hypofractionated radiotherapy by Tomotherapy along with appropriate systemic therapy. There were 24 primary, and 9 secondary lung cancer cases. The radiation doses ranged from 4.5 to 7.0 Gy per fraction, multiplied by 8–16 fractions. The median dose per fraction was 4.5 Gy (range, 4.5-7.0 Gy), and the median total dose was 49.5 Gy (range, 45–72 Gy). The median estimated biological effective dose at 10 Gy (BED 10 ) was 71.8 Gy (range, 65.3–119.0 Gy), and that at 3 Gy (BED 3 ) was 123.8 Gy (range, 112.5–233.3 Gy). The mean lung dose (MLD) was constrained mainly under 1200 cGy. The median gross tumor volume (GTV) was 27.9 cm 3 (range: 2.5–178.1 cm 3 ). The median follow-up period was 25.8 months (range, 3.0–60.7 months). The median overall survival (OS) time was 32.1 months for the 24 primary lung cancer patients, and >40 months for the 9 metastatic lung patients. The median survival time of the patients with extra-pulmonary disease (EPD) was 11.2 months versus >50 months (not reached) in the patients without EPD (p < 0.001). Those patients with smaller GTV (≦27.9 cm 3 ) had a better survival than those with larger GTV (>27.9 cm 3 ): >40 months versus 12.85 months (p = 0.047). The patients with ≦2 lesions had a median survival >40 months, whereas those with ≧3 lesions had 26 months (p = 0.065). The 2-year local control (LC) rate was 94.7%. Only 2 patients (6.1%) developed ≧grade 3 radiation pneumonitis. Using Tomotherapy in hypofractionation may be effective for selected primary or secondary lung oligometastatic diseases, without causing significant toxicities. Pulmonary oligometastasis patients without EPD had better survival outcomes than those with EPD. Moreover, GTV is more significant than

  11. Hypofractionated radiotherapy for primary or secondary oligometastatic lung cancer using Tomotherapy

    Science.gov (United States)

    2012-01-01

    Background To retrospectively review the outcome of patients with primary or secondary oligometastatic lung cancer, treated with hypofractionated Tomotherapy. Methods Between April 2007 and June 2011, a total of 33 patients with oligometastatic intrapulmonary lesions underwent hypofractionated radiotherapy by Tomotherapy along with appropriate systemic therapy. There were 24 primary, and 9 secondary lung cancer cases. The radiation doses ranged from 4.5 to 7.0 Gy per fraction, multiplied by 8–16 fractions. The median dose per fraction was 4.5 Gy (range, 4.5-7.0 Gy), and the median total dose was 49.5 Gy (range, 45–72 Gy). The median estimated biological effective dose at 10 Gy (BED10) was 71.8 Gy (range, 65.3–119.0 Gy), and that at 3 Gy (BED3) was 123.8 Gy (range, 112.5–233.3 Gy). The mean lung dose (MLD) was constrained mainly under 1200 cGy. The median gross tumor volume (GTV) was 27.9 cm3 (range: 2.5–178.1 cm3). Results The median follow-up period was 25.8 months (range, 3.0–60.7 months). The median overall survival (OS) time was 32.1 months for the 24 primary lung cancer patients, and >40 months for the 9 metastatic lung patients. The median survival time of the patients with extra-pulmonary disease (EPD) was 11.2 months versus >50 months (not reached) in the patients without EPD (p 27.9 cm3): >40 months versus 12.85 months (p = 0.047). The patients with ≦2 lesions had a median survival >40 months, whereas those with ≧3 lesions had 26 months (p = 0.065). The 2-year local control (LC) rate was 94.7%. Only 2 patients (6.1%) developed ≧grade 3 radiation pneumonitis. Conclusion Using Tomotherapy in hypofractionation may be effective for selected primary or secondary lung oligometastatic diseases, without causing significant toxicities. Pulmonary oligometastasis patients without EPD had better survival outcomes than those with EPD. Moreover, GTV is more significant than lesion number in

  12. Acute toxicity profile in prostate cancer with conventional and hypofractionated treatment

    International Nuclear Information System (INIS)

    Viani, Gustavo Arruda; Zulliani, Giseli Correa; Stefano, Eduardo Jose; Silva, Lucas Bernardes Godoy da; Silva, Bruna Bueno da; Crempe, Yuri Bonicelli; Martins, Vinicius Spazzapan; Ferrari, Ricardo Jose Rambaiolo; Pólo, Mariana Colbachini; Rossi, Bruno Thiago; Suguikawa, Elton

    2013-01-01

    To compare the acute toxicities in radical treatment of prostate cancer between conventional schedule (C-ARM) with 78 Gy/39 fractions and hypofractionation conformal treatment (H-ARM) with 69 Gy/23 fractions. This prospective double arm study consisted of 217 patients with prostate cancer, 112 in H-ARM and 105 in C-ARM arm. C-ARM received conventional six- field conformal radiotherapy with 78 Gy in 39 fractions while H-ARM received hypofractionation with 69 Gy in 23 fractions. Weekly assessment of acute reactions was done during treatment and with one, and 3 months using RTOG scale. Univariated analysis was performed to evaluate differences between the incidences of acute reaction in the treatment arms. Variables with p value less than 0.1 were included in the multivariated logistic regression. There was no difference between H-ARM versus C-ARM for severity and incidence in genitourinary (GU) and gastrointestinal (GI) acute toxicity. During the treatment comparing H-ARM with C-ARM no differences was observed for GI toxicity (grade 0–3; H-ARM = 45.5%, 34%, 18.7% and 1.8% versus C-ARM = 47.6%, 35.2%, 17.2% and 0). For acute GU toxicity no difference was detected between H-ARM (grade 0–3; 22.3%, 54.5%, 18.7% and 4.5%) and C-ARM (grade 0–3; 25.8%, 53.3%, 17.1% and 3.8%). At the 3- months follow-up, persistent Grade > =2 acute GU and GI toxicity were 2.5% and 1.8% in H-ARM versus 5.7% and 3% in C-ARM (p > 0.05). In univariated and multivariated analyses, there was not any dosimetric predictor for GI and GU toxicity. Our data demonstrate that hypofractionated radiotherapy achieving high biological effective dose using conformal radiotherapy is feasible for prostate cancer, being well tolerated with minimal severe acute toxicity

  13. Hypofractionated radiotherapy for primary or secondary oligometastatic lung cancer using Tomotherapy

    Directory of Open Access Journals (Sweden)

    Chang Heng-Jui

    2012-12-01

    Full Text Available Abstract Background To retrospectively review the outcome of patients with primary or secondary oligometastatic lung cancer, treated with hypofractionated Tomotherapy. Methods Between April 2007 and June 2011, a total of 33 patients with oligometastatic intrapulmonary lesions underwent hypofractionated radiotherapy by Tomotherapy along with appropriate systemic therapy. There were 24 primary, and 9 secondary lung cancer cases. The radiation doses ranged from 4.5 to 7.0 Gy per fraction, multiplied by 8–16 fractions. The median dose per fraction was 4.5 Gy (range, 4.5-7.0 Gy, and the median total dose was 49.5 Gy (range, 45–72 Gy. The median estimated biological effective dose at 10 Gy (BED10 was 71.8 Gy (range, 65.3–119.0 Gy, and that at 3 Gy (BED3 was 123.8 Gy (range, 112.5–233.3 Gy. The mean lung dose (MLD was constrained mainly under 1200 cGy. The median gross tumor volume (GTV was 27.9 cm3 (range: 2.5–178.1 cm3. Results The median follow-up period was 25.8 months (range, 3.0–60.7 months. The median overall survival (OS time was 32.1 months for the 24 primary lung cancer patients, and >40 months for the 9 metastatic lung patients. The median survival time of the patients with extra-pulmonary disease (EPD was 11.2 months versus >50 months (not reached in the patients without EPD (p 3 had a better survival than those with larger GTV (>27.9 cm3: >40 months versus 12.85 months (p = 0.047. The patients with ≦2 lesions had a median survival >40 months, whereas those with ≧3 lesions had 26 months (p = 0.065. The 2-year local control (LC rate was 94.7%. Only 2 patients (6.1% developed ≧grade 3 radiation pneumonitis. Conclusion Using Tomotherapy in hypofractionation may be effective for selected primary or secondary lung oligometastatic diseases, without causing significant toxicities. Pulmonary oligometastasis patients without EPD had better survival outcomes than those with

  14. Image-guided adaptive gating of lung cancer radiotherapy: a computer simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Aristophanous, Michalis; Rottmann, Joerg; Park, Sang-June; Berbeco, Ross I [Department of Radiation Oncology, Brigham and Women' s Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA (United States); Nishioka, Seiko [Department of Radiology, NTT Hospital, Sapporo (Japan); Shirato, Hiroki, E-mail: maristophanous@lroc.harvard.ed [Department of Radiation Medicine, Hokkaido University School of Medicine, Sapporo (Japan)

    2010-08-07

    The purpose of this study is to investigate the effect that image-guided adaptation of the gating window during treatment could have on the residual tumor motion, by simulating different gated radiotherapy techniques. There are three separate components of this simulation: (1) the 'Hokkaido Data', which are previously measured 3D data of lung tumor motion tracks and the corresponding 1D respiratory signals obtained during the entire ungated radiotherapy treatments of eight patients, (2) the respiratory gating protocol at our institution and the imaging performed under that protocol and (3) the actual simulation in which the Hokkaido Data are used to select tumor position information that could have been collected based on the imaging performed under our gating protocol. We simulated treatments with a fixed gating window and a gating window that is updated during treatment. The patient data were divided into different fractions, each with continuous acquisitions longer than 2 min. In accordance to the imaging performed under our gating protocol, we assume that we have tumor position information for the first 15 s of treatment, obtained from kV fluoroscopy, and for the rest of the fractions the tumor position is only available during the beam-on time from MV imaging. The gating window was set according to the information obtained from the first 15 s such that the residual motion was less than 3 mm. For the fixed gating window technique the gate remained the same for the entire treatment, while for the adaptive technique the range of the tumor motion during beam-on time was measured and used to adapt the gating window to keep the residual motion below 3 mm. The algorithm used to adapt the gating window is described. The residual tumor motion inside the gating window was reduced on average by 24% for the patients with regular breathing patterns and the difference was statistically significant (p-value = 0.01). The magnitude of the residual tumor motion

  15. Amplifying genetic logic gates.

    Science.gov (United States)

    Bonnet, Jerome; Yin, Peter; Ortiz, Monica E; Subsoontorn, Pakpoom; Endy, Drew

    2013-05-03

    Organisms must process information encoded via developmental and environmental signals to survive and reproduce. Researchers have also engineered synthetic genetic logic to realize simpler, independent control of biological processes. We developed a three-terminal device architecture, termed the transcriptor, that uses bacteriophage serine integrases to control the flow of RNA polymerase along DNA. Integrase-mediated inversion or deletion of DNA encoding transcription terminators or a promoter modulates transcription rates. We realized permanent amplifying AND, NAND, OR, XOR, NOR, and XNOR gates actuated across common control signal ranges and sequential logic supporting autonomous cell-cell communication of DNA encoding distinct logic-gate states. The single-layer digital logic architecture developed here enables engineering of amplifying logic gates to control transcription rates within and across diverse organisms.

  16. Cardiac gated ventilation

    International Nuclear Information System (INIS)

    Hanson, C.W. III; Hoffman, E.A.

    1995-01-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart

  17. Gated Treatment Delivery Verification With On-Line Megavoltage Fluoroscopy

    International Nuclear Information System (INIS)

    Tai An; Christensen, James D.; Gore, Elizabeth; Khamene, Ali; Boettger, Thomas; Li, X. Allen

    2010-01-01

    Purpose: To develop and clinically demonstrate the use of on-line real-time megavoltage (MV) fluoroscopy for gated treatment delivery verification. Methods and Materials: Megavoltage fluoroscopy (MVF) image sequences were acquired using a flat panel equipped for MV cone-beam CT in synchrony with the respiratory signal obtained from the Anzai gating device. The MVF images can be obtained immediately before or during gated treatment delivery. A prototype software tool (named RTReg4D) was developed to register MVF images with phase-sequenced digitally reconstructed radiograph images generated from the treatment planning system based on four-dimensional CT. The image registration can be used to reposition the patient before or during treatment delivery. To demonstrate the reliability and clinical usefulness, the system was first tested using a thoracic phantom and then prospectively in actual patient treatments under an institutional review board-approved protocol. Results: The quality of the MVF images for lung tumors is adequate for image registration with phase-sequenced digitally reconstructed radiographs. The MVF was found to be useful for monitoring inter- and intrafractional variations of tumor positions. With the planning target volume contour displayed on the MVF images, the system can verify whether the moving target stays within the planning target volume margin during gated delivery. Conclusions: The use of MVF images was found to be clinically effective in detecting discrepancies in tumor location before and during respiration-gated treatment delivery. The tools and process developed can be useful for gated treatment delivery verification.

  18. Accuracy and effectiveness of self-gating signals in free-breathing three-dimensional cardiac cine magnetic resonance imaging

    International Nuclear Information System (INIS)

    Li Shuo; Gao Song; Wang Lei; Zhu Yan-Chun; Yang Jie; Xie Yao-Qin; Fu Nan; Wang Yi

    2016-01-01

    Conventional multiple breath-hold two-dimensional (2D) balanced steady-state free precession (SSFP) presents many difficulties in cardiac cine magnetic resonance imaging (MRI). Recently, a self-gated free-breathing three-dimensional (3D) SSFP technique has been proposed as an alternative in many studies. However, the accuracy and effectiveness of self-gating signals have been barely studied before. Since self-gating signals are crucially important in image reconstruction, a systematic study of self-gating signals and comparison with external monitored signals are needed.Previously developed self-gated free-breathing 3D SSFP techniques are used on twenty-eight healthy volunteers. Both electrocardiographic (ECG) and respiratory bellow signals are also acquired during the scan as external signals. Self-gating signal and external signal are compared by trigger and gating window. Gating window is proposed to evaluate the accuracy and effectiveness of respiratory self-gating signal. Relative deviation of the trigger and root-mean-square-deviation of the cycle duration are calculated. A two-tailed paired t-test is used to identify the difference between self-gating and external signals. A Wilcoxon signed rank test is used to identify the difference between peak and valley self-gating triggers.The results demonstrate an excellent correlation ( P = 0, R > 0.99) between self-gating and external triggers. Wilcoxon signed rank test shows that there is no significant difference between peak and valley self-gating triggers for both cardiac ( H = 0, P > 0.10) and respiratory ( H = 0, P > 0.44) motions. The difference between self-gating and externally monitored signals is not significant (two-tailed paired-sample t-test: H = 0, P > 0.90).The self-gating signals could demonstrate cardiac and respiratory motion accurately and effectively as ECG and respiratory bellow. The difference between the two methods is not significant and can be explained. Furthermore, few ECG trigger errors

  19. Hypofractionated whole breast irradiation: New standard in early breast cancer after breast-conserving surgery

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Su; Shin, Kyung Hwan; Choi, Noorie; Lee, Sea Won [Dept. of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2016-06-15

    Hypofractionated whole breast irradiation (HF-WBI) has been proved effective and safe and even better for late or acute radiation toxicity for early breast cancer. Moreover, it improves patient convenience, quality of life and is expected to be advantageous in the medical care system by reducing overall cost. In this review, we examined key randomized trials of HF-WBI, focusing on adequate patient selection as suggested by the American Society of Therapeutic Radiology and Oncology (ASTRO) guideline and the radiobiologic aspects of HF-WBI in relation to its adoption into clinical settings. Further investigation to identify the current practice pattern or cost effectiveness is warranted under the national health insurance service system in Korea.

  20. Hypo-fractionated treatment in radiotherapy: radio-biological models Tcp and NTCP

    International Nuclear Information System (INIS)

    Astudillo V, A. J.; Mitsoura, E.; Paredes G, L.; Resendiz G, G.

    2014-08-01

    At the present time the breast cancer in Mexico has the first place of incidence of the malignant neoplasia s in the women, and represents 11.34% of all the cancer cases. On the other hand, the treatments for cancer by means of ionizing radiations have been dominated under the approaches of the medical radio-oncologists which have been based on test and error by many years. The radio-biological models, as the Tcp, NTCP and dosimetric variables, for their clinical application in the conventional radiotherapy with hypo-fractionation have as purpose predicting personalized treatment plans that they present most probability of tumor control and minor probability of late reactions, becoming this way support tools in the decisions taking for the patient treatments planning of Medical Physicists and Radio-oncologists. (Author)

  1. Respiratory correlated cone beam CT

    International Nuclear Information System (INIS)

    Sonke, Jan-Jakob; Zijp, Lambert; Remeijer, Peter; Herk, Marcel van

    2005-01-01

    conclusion, we have successfully implemented a respiratory correlated CBCT procedure yielding a 4D dataset. With respiratory correlated CBCT on a linear accelerator, the mean position, trajectory, and shape of a moving tumor can be verified just prior to treatment. Such verification reduces respiration induced geometrical uncertainties, enabling safe delivery of 4D radiotherapy such as gated radiotherapy with small margins

  2. Gate valve performance prediction

    International Nuclear Information System (INIS)

    Harrison, D.H.; Damerell, P.S.; Wang, J.K.; Kalsi, M.S.; Wolfe, K.J.

    1994-01-01

    The Electric Power Research Institute is carrying out a program to improve the performance prediction methods for motor-operated valves. As part of this program, an analytical method to predict the stem thrust required to stroke a gate valve has been developed and has been assessed against data from gate valve tests. The method accounts for the loads applied to the disc by fluid flow and for the detailed mechanical interaction of the stem, disc, guides, and seats. To support development of the method, two separate-effects test programs were carried out. One test program determined friction coefficients for contacts between gate valve parts by using material specimens in controlled environments. The other test program investigated the interaction of the stem, disc, guides, and seat using a special fixture with full-sized gate valve parts. The method has been assessed against flow-loop and in-plant test data. These tests include valve sizes from 3 to 18 in. and cover a considerable range of flow, temperature, and differential pressure. Stem thrust predictions for the method bound measured results. In some cases, the bounding predictions are substantially higher than the stem loads required for valve operation, as a result of the bounding nature of the friction coefficients in the method

  3. Stanford, Duke, Rice,... and Gates?

    Science.gov (United States)

    Carey, Kevin

    2009-01-01

    This article presents an open letter to Bill Gates. In his letter, the author suggests that Bill Gates should build a brand-new university, a great 21st-century institution of higher learning. This university will be unlike anything the world has ever seen. He asks Bill Gates not to stop helping existing colleges create the higher-education system…

  4. Double optical gating

    Science.gov (United States)

    Gilbertson, Steve

    The observation and control of dynamics in atomic and molecular targets requires the use of laser pulses with duration less than the characteristic timescale of the process which is to be manipulated. For electron dynamics, this time scale is on the order of attoseconds where 1 attosecond = 10 -18 seconds. In order to generate pulses on this time scale, different gating methods have been proposed. The idea is to extract or "gate" a single pulse from an attosecond pulse train and switch off all the other pulses. While previous methods have had some success, they are very difficult to implement and so far very few labs have access to these unique light sources. The purpose of this work is to introduce a new method, called double optical gating (DOG), and to demonstrate its effectiveness at generating high contrast single isolated attosecond pulses from multi-cycle lasers. First, the method is described in detail and is investigated in the spectral domain. The resulting attosecond pulses produced are then temporally characterized through attosecond streaking. A second method of gating, called generalized double optical gating (GDOG), is also introduced. This method allows attosecond pulse generation directly from a carrier-envelope phase un-stabilized laser system for the first time. Next the methods of DOG and GDOG are implemented in attosecond applications like high flux pulses and extreme broadband spectrum generation. Finally, the attosecond pulses themselves are used in experiments. First, an attosecond/femtosecond cross correlation is used for characterization of spatial and temporal properties of femtosecond pulses. Then, an attosecond pump, femtosecond probe experiment is conducted to observe and control electron dynamics in helium for the first time.

  5. [Hypofractionated radiation therapy for the treatment of malignant melanoma and squamous cell carcinoma in dogs and cats].

    Science.gov (United States)

    Kinzel, Sylvia; Hein, Sven; Stopinski, Thaddeus; Koch, Johannes; Buecker, Arno; Treusacher, Hans-Peter; Schmachtenberg, Axel; Jansen, Thomas; Eble, Michael; Küpper, Wernen

    2003-01-01

    This study describes the experience with hypofractionated radiation therapy of squamous cell carcinoma and melanoma in dogs and cats. A total dose of 32-48 Gray (Gy) was delivered once a week in 8 Gy fractions. 34 animals in which a complete surgical excision was impossible were treated. There was no tumor detectable macroscopically in 14 patients at the beginning of radiation therapy. In 20 animals the median volume of the tumor was 9.9 cm3. The median survival times and the local tumor control of squamous cell carcinoma of the oral and nasal cavities and of the body are comparable to results which were reached with a Monday-Wednesday-Friday scheme. For the treatment of Melanoma the hypofractionated radiation therapy is first choice. There are no significant side effects. Late side effects did not occur. 88% of the owners are satisfied with this kind of treatment and would choose it again.

  6. Lungs and Respiratory System

    Science.gov (United States)

    ... Videos for Educators Search English Español Lungs and Respiratory System KidsHealth / For Parents / Lungs and Respiratory System ... ll have taken at least 600 million breaths. Respiratory System Basics All of this breathing couldn't ...

  7. Neonatal respiratory distress syndrome

    Science.gov (United States)

    Hyaline membrane disease (HMD); Infant respiratory distress syndrome; Respiratory distress syndrome in infants; RDS - infants ... improves slowly after that. Some infants with severe respiratory distress syndrome will die. This most often occurs ...

  8. Hypofractionated Intensity Modulated Radiation Therapy in Combined Modality Treatment for Bladder Preservation in Elderly Patients With Invasive Bladder Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Turgeon, Guy-Anne [Department of Oncology, Division of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Souhami, Luis, E-mail: luis.souhami@muhc.mcgill.ca [Department of Oncology, Division of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Cury, Fabio L.; Faria, Sergio L.; Duclos, Marie [Department of Oncology, Division of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Sturgeon, Jeremy [Department of Medical Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Kassouf, Wassim [Department of Urology, McGill University Health Centre, Montreal, Quebec (Canada)

    2014-02-01

    Purpose/Objective(s): To review our experience with bladder-preserving trimodality treatment (TMT) using hypofractionated intensity modulated radiation therapy (IMRT) for the treatment of elderly patients with muscle-invasive bladder cancer. Methods and Materials: Retrospective study of elderly patients treated with TMT using hypofractionated IMRT (50 Gy in 20 fractions) with concomitant weekly radiosensitizing chemotherapy. Eligibility criteria were as follows: age ≥70 years, a proven diagnosis of muscle-invasive transitional cell bladder carcinoma, stage T2-T3N0M0 disease, and receipt of TMT with curative intent. Response rate was assessed by cystoscopic evaluation and bladder biopsy. Results: 24 patients with a median age of 79 years were eligible. A complete response was confirmed in 83% of the patients. Of the remaining patients, 1 of them underwent salvage cystectomy, and no disease was found in the bladder on histopathologic assessment. After a median follow-up time of 28 months, of the patients with a complete response, 2 patients had muscle-invasive recurrence, 1 experienced locoregional failure, and 3 experienced distant metastasis. The overall and cancer-specific survival rates at 3 years were 61% and 71%, respectively. Of the surviving patients, 75% have a disease-free and functioning bladder. All patients completed hypofractionated IMRT, and 19 patients tolerated all 4 cycles of chemotherapy. Acute grade 3 gastrointestinal or genitourinary toxicities occurred in only 4% of the patients, and acute grade 3 or 4 hematologic toxicities, liver toxicities, or both were experienced by 17% of the cohort. No patient experienced grade 4 gastrointestinal or genitourinary toxicity. Conclusions: Hypofractionated IMRT with concurrent radiosensitizing chemotherapy appears to be an effective and well-tolerated curative treatment strategy in the elderly population and should be considered for patients who are not candidates for cystectomy or who wish to avoid

  9. Noise Gating Solar Images

    Science.gov (United States)

    DeForest, Craig; Seaton, Daniel B.; Darnell, John A.

    2017-08-01

    I present and demonstrate a new, general purpose post-processing technique, "3D noise gating", that can reduce image noise by an order of magnitude or more without effective loss of spatial or temporal resolution in typical solar applications.Nearly all scientific images are, ultimately, limited by noise. Noise can be direct Poisson "shot noise" from photon counting effects, or introduced by other means such as detector read noise. Noise is typically represented as a random variable (perhaps with location- or image-dependent characteristics) that is sampled once per pixel or once per resolution element of an image sequence. Noise limits many aspects of image analysis, including photometry, spatiotemporal resolution, feature identification, morphology extraction, and background modeling and separation.Identifying and separating noise from image signal is difficult. The common practice of blurring in space and/or time works because most image "signal" is concentrated in the low Fourier components of an image, while noise is evenly distributed. Blurring in space and/or time attenuates the high spatial and temporal frequencies, reducing noise at the expense of also attenuating image detail. Noise-gating exploits the same property -- "coherence" -- that we use to identify features in images, to separate image features from noise.Processing image sequences through 3-D noise gating results in spectacular (more than 10x) improvements in signal-to-noise ratio, while not blurring bright, resolved features in either space or time. This improves most types of image analysis, including feature identification, time sequence extraction, absolute and relative photometry (including differential emission measure analysis), feature tracking, computer vision, correlation tracking, background modeling, cross-scale analysis, visual display/presentation, and image compression.I will introduce noise gating, describe the method, and show examples from several instruments (including SDO

  10. A quantum Fredkin gate

    Science.gov (United States)

    Patel, Raj B.; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C.; Pryde, Geoff J.

    2016-01-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently. PMID:27051868

  11. A quantum Fredkin gate.

    Science.gov (United States)

    Patel, Raj B; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C; Pryde, Geoff J

    2016-03-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently.

  12. Helical tomotherapy for SIB and hypo-fractionated treatments in lung carcinomas: A 4D Monte Carlo treatment planning study

    International Nuclear Information System (INIS)

    Sterpin, Edmond; Janssens, Guillaume; Orban de Xivry, Jonathan; Goossens, Samuel; Wanet, Marie; Lee, John A.; Delor, Antoine; Bol, Vanesa; Vynckier, Stefaan; Gregoire, Vincent; Geets, Xavier

    2012-01-01

    Purpose: To evaluate the impact of intra-fraction motion induced by regular breathing on treatment quality for helical tomotherapy treatments. Material and methods: Four patients treated by simultaneous-integrated boost (SIB) and three by hypo-fractionated stereotactic treatments (hypo-fractionated, 18 Gy/fraction) were included. All patients were coached to ensure regular breathing. For the SIB group, the tumor volume was delineated using CT information only (CTV CT ) and the boost region was based on PET information (GTV PET , no CTV extension). In the hypo-fractionated group, a GTV based on CT information was contoured. In both groups, ITVs were defined according to 4D data. The PTV included the ITV plus a setup error margin. The treatment was planned using the tomotherapy TPS on 3D CT images. In order to verify the impact of intra-fraction motion and interplay effects, dose calculations were performed using a previously validated Monte Carlo model of tomotherapy (TomoPen): first on the planning 3D CT (“planned dose”) and second, on the 10 phases of the 4D scan. For the latter, two dose distributions, termed “interplay simulated” or “no interplay” were computed with and without beamlet-phase correlation over the 10 phases and combined using deformable dose registration. Results: In all cases, DVHs of “interplay simulated” dose distributions complied within 1% of the original clinical objectives used for planning, defined according to ICRU (report 83) and RTOG (trials 0236 and 0618) recommendations, for SIB and hypo-fractionated groups, respectively. For one patient in the hypo-fractionated group, D mean to the CTV CT was 2.6% and 2.5% higher than “planned” for “interplay simulated” and “no interplay”, respectively. Conclusion: For the patients included in this study, assuming regular breathing, the results showed that interplay of breathing and tomotherapy delivery motions did not affect significantly plan delivery accuracy. Hence

  13. Video-coaching as biofeedback tool to improve gated treatments. Possibilities and limitations

    International Nuclear Information System (INIS)

    Cossmann, Peter H.

    2012-01-01

    For respiratory gated radiotherapy the manufacturers of linear accelerators offer dedicated gating technologies. The video-based Varian RPM Gating system (Varian Medical Systems, Palo Alto/CA, USA) includes in a standard configuration a support tool for regular breathing called audiocoaching. As this approach has limitations regarding direct control of the patient's breathing due to a missing feedback, we designed an additional tool offering videocoaching. In order to evaluate the impact of this additional functionality, we measured parameters defining the image quality of 4D-CT data as well as the treatment duration which is mainly influenced by the patient's limited ability to achieve a stable breathing pattern. (orig.)

  14. Evaluation of image-guided radiation therapy (IGRT) technologies and their impact on the outcomes of hypofractionated prostate cancer treatments: A radiobiologic analysis

    International Nuclear Information System (INIS)

    Song, William Y.; Schaly, Bryan; Bauman, Glenn; Battista, Jerry J.; Van Dyk, Jake

    2006-01-01

    Purpose: To quantify the mitigation of geometric uncertainties achieved with the application of various patient setup techniques during the delivery of hypofractionated prostate cancer treatments, using tumor control probability (TCP) and normal tissue complication probability. Methods and Materials: Five prostate cancer patients with ∼16 treatment CT studies, taken during the course of their radiation therapy (77 total), were analyzed. All patients were planned twice with an 18 MV six-field conformal technique, with 10- and 5-mm margin sizes, with various hypofractionation schedules (5 to 35 fractions). Subsequently, four clinically relevant patient setup techniques (laser guided and image guided) were simulated to deliver such schedules. Results: As hypothesized, the impact of geometric uncertainties on clinical outcomes increased with more hypofractionated schedules. However, the absolute gain in TCP due to hypofractionation (up to 21.8% increase) was significantly higher compared with the losses due to geometric uncertainties (up to 8.6% decrease). Conclusions: The results of this study suggest that, although the impact of geometric uncertainties on the treatment outcomes increases as the number of fractions decrease, the reduction in TCP due to the uncertainties does not significantly offset the expected theoretical gain in TCP by hypofractionation

  15. SU-F-T-526: A Comparative Study On Gating Efficiency of Varian RPM Device and Calypso System

    Energy Technology Data Exchange (ETDEWEB)

    Ravindran, P [Christian Medical College Hospital, Vellore (India); Wui Ann, W; Lim, Y [The Brunei Cancer Center (Brunei Darussalam)

    2016-06-15

    Purpose: In general, the linear accelerator is gated using respiratory signal obtained by way of external sensors to account for the breathing motion during radiotherapy. One of the commonly used gating devices is the Varian RPM device. Calypso system that uses electromagnetic tracking of implanted or surface transponders could also be used for gating. The aim of this study is to compare the gating efficiency of RPM device and the calypso system by phantom studies. Methods: An ArcCheck insert was used as the phantom with a Gafchromic film placed in its holder. The ArcCheck insert was placed on a Motion Sim platform and moved in the longitudinal direction simulating a respiratory motion with a period of 5 seconds and amplitude of ±6mm. The Gafchromic film was exposed to a 2 × 2cm{sup 2} field, i) with the phantom static, ii) phantom moving but ungated iii) gated with gating window of 2mm and 3mm. This was repeated with Calypso system using surface transponders with the same gating window. The Gafchromic films were read with an EPSON 11000 flatbed scanner and analysed with ‘Medphysto’ software. Results: The full width at half maximum (FWHM) as measured with film at the level of the film holder was 1.65cm when the phantom was static. FWHM measured with phantom moving and without gating was 1.16 cm and penumbra was 7 mm (80–20%) on both sides. When the beam was gated with 2 mm gating window the FWHM was 1.8 cm with RPM device and 1.9 cm with Calypso. Similarly, when the beam was gated with 3 mm window, the FWHM was 1.9cm with RPM device and 2cm with Calypso. Conclusion: This work suggests that the gating efficiency of RPM device is better than that of the Calypso with surface transponder, with reference to the latency in gating.

  16. Voltage-gated proton channel is expressed on phagosomes

    International Nuclear Information System (INIS)

    Okochi, Yoshifumi; Sasaki, Mari; Iwasaki, Hirohide; Okamura, Yasushi

    2009-01-01

    Voltage-gated proton channel has been suggested to help NADPH oxidase activity during respiratory burst of phagocytes through its activities of compensating charge imbalance and regulation of pH. In phagocytes, robust production of reactive oxygen species occurs in closed membrane compartments, which are called phagosomes. However, direct evidence for the presence of voltage-gated proton channels in phagosome has been lacking. In this study, the expression of voltage-gated proton channels was studied by Western blot with the antibody specific to the voltage-sensor domain protein, VSOP/Hv1, that has recently been identified as the molecular correlate for the voltage-gated proton channel. Phagosomal membranes of neutrophils contain VSOP/Hv1 in accordance with subunits of NADPH oxidases, gp91, p22, p47 and p67. Superoxide anion production upon PMA activation was significantly reduced in neutrophils from VSOP/Hv1 knockout mice. These are consistent with the idea that voltage-gated proton channels help NADPH oxidase in phagocytes to produce reactive oxygen species.

  17. Multiple Independent Gate FETs: How Many Gates Do We Need?

    OpenAIRE

    Amarù, Luca; Hills, Gage; Gaillardon, Pierre-Emmanuel; Mitra, Subhasish; De Micheli, Giovanni

    2015-01-01

    Multiple Independent Gate Field Effect Transistors (MIGFETs) are expected to push FET technology further into the semiconductor roadmap. In a MIGFET, supplementary gates either provide (i) enhanced conduction properties or (ii) more intelligent switching functions. In general, each additional gate also introduces a side implementation cost. To enable more efficient digital systems, MIGFETs must leverage their expressive power to realize complex logic circuits with few physical resources. Rese...

  18. Middle East Respiratory Syndrome

    Centers for Disease Control (CDC) Podcasts

    2014-07-07

    This podcast discusses Middle East Respiratory Syndrome, or MERS, a viral respiratory illness caused by Middle East Respiratory Syndrome Coronavirus—MERS-CoV.  Created: 7/7/2014 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 7/7/2014.

  19. 100-nm gate lithography for double-gate transistors

    Science.gov (United States)

    Krasnoperova, Azalia A.; Zhang, Ying; Babich, Inna V.; Treichler, John; Yoon, Jung H.; Guarini, Kathryn; Solomon, Paul M.

    2001-09-01

    The double gate field effect transistor (FET) is an exploratory device that promises certain performance advantages compared to traditional CMOS FETs. It can be scaled down further than the traditional devices because of the greater electrostatic control by the gates on the channel (about twice as short a channel length for the same gate oxide thickness), has steeper sub-threshold slope and about double the current for the same width. This paper presents lithographic results for double gate FET's developed at IBM's T. J. Watson Research Center. The device is built on bonded wafers with top and bottom gates self-aligned to each other. The channel is sandwiched between the top and bottom polysilicon gates and the gate length is defined using DUV lithography. An alternating phase shift mask was used to pattern gates with critical dimensions of 75 nm, 100 nm and 125 nm in photoresist. 50 nm gates in photoresist have also been patterned by 20% over-exposure of nominal 100 nm lines. No trim mask was needed because of a specific way the device was laid out. UV110 photoresist from Shipley on AR-3 antireflective layer were used. Process windows, developed and etched patterns are presented.

  20. Hypofractionated Versus Standard Radiation Therapy With or Without Temozolomide for Older Glioblastoma Patients

    International Nuclear Information System (INIS)

    Arvold, Nils D.; Tanguturi, Shyam K.; Aizer, Ayal A.; Wen, Patrick Y.; Reardon, David A.; Lee, Eudocia Q.; Nayak, Lakshmi; Christianson, Laura W.; Horvath, Margaret C.; Dunn, Ian F.; Golby, Alexandra J.; Johnson, Mark D.; Claus, Elizabeth B.; Chiocca, E. Antonio; Ligon, Keith L.; Alexander, Brian M.

    2015-01-01

    Purpose: Older patients with newly diagnosed glioblastoma have poor outcomes, and optimal treatment is controversial. Hypofractionated radiation therapy (HRT) is frequently used but has not been compared to patients receiving standard fractionated radiation therapy (SRT) and temozolomide (TMZ). Methods and Materials: We conducted a retrospective analysis of patients ≥65 years of age who received radiation for the treatment of newly diagnosed glioblastoma from 1994 to 2013. The distribution of clinical covariates across various radiation regimens was analyzed for possible selection bias. Survival was calculated using the Kaplan-Meier method. Comparison of hypofractionated radiation (typically, 40 Gy/15 fractions) versus standard fractionation (typically, 60 Gy/30 fractions) in the setting of temozolomide was conducted using Cox regression and propensity score analysis. Results: Patients received SRT + TMZ (n=57), SRT (n=35), HRT + TMZ (n=34), or HRT (n=9). Patients receiving HRT were significantly older (median: 79 vs 69 years of age; P<.001) and had worse baseline performance status (P<.001) than those receiving SRT. On multivariate analysis, older age (adjusted hazard ratio [AHR]: 1.06; 95% confidence interval [CI]: 1.01-1.10, P=.01), lower Karnofsky performance status (AHR: 1.02; 95% CI: 1.01-1.03; P=.01), multifocal disease (AHR: 2.11; 95% CI: 1.23-3.61, P=.007), and radiation alone (vs SRT + TMZ; SRT: AHR: 1.72; 95% CI: 1.06-2.79; P=.03; HRT: AHR: 3.92; 95% CI: 1.44-10.60, P=.007) were associated with decreased overall survival. After propensity score adjustment, patients receiving HRT with TMZ had similar overall survival compared with those receiving SRT with TMZ (AHR: 1.10, 95% CI: 0.50-2.4, P=.82). Conclusions: With no randomized data demonstrating equivalence between HRT and SRT in the setting of TMZ for glioblastoma, significant selection bias exists in the implementation of HRT. Controlling for this bias, we observed similar overall

  1. 4D radiobiological modelling of the interplay effect in conventionally and hypofractionated lung tumour IMRT.

    Science.gov (United States)

    Selvaraj, J; Uzan, J; Baker, C; Nahum, A

    2015-01-01

    To study the impact of the interplay between respiration-induced tumour motion and multileaf collimator leaf movements in intensity-modulated radiotherapy (IMRT) as a function of number of fractions, dose rate on population mean tumour control probability ([Formula: see text]) using an in-house developed dose model. Delivered dose was accumulated in a voxel-by-voxel basis inclusive of tumour motion over the course of treatment. The effect of interplay on dose and [Formula: see text] was studied for conventionally and hypofractionated treatments using digital imaging and communications in medicine data sets. Moreover, the effect of dose rate on interplay was also studied for single-fraction treatments. Simulations were repeated several times to obtain [Formula: see text] for each plan. The average variation observed in mean dose to the target volumes were -0.76% ± 0.36% for the 20-fraction treatment and -0.26% ± 0.68% and -1.05% ± 0.98% for the three- and single-fraction treatments, respectively. For the 20-fraction treatment, the drop in [Formula: see text] was -1.05% ± 0.39%, whereas for the three- and single-fraction treatments, it was -2.80% ± 1.68% and -4.00% ± 2.84%, respectively. By reducing the dose rate from 600 to 300 MU min(-1) for the single-fraction treatments, the drop in [Formula: see text] was reduced by approximately 1.5%. The effect of interplay on [Formula: see text] is negligible for conventionally fractionated treatments, whereas considerable drop in [Formula: see text] is observed for the three- and single-fraction treatments. Reduced dose rate could be used in hypofractionated treatments to reduce the interplay effect. A novel in silico dose model is presented to determine the impact of interplay effect in IMRT treatments on [Formula: see text].

  2. Outcomes and toxicity from a prospective study of moderately hypofractionated radiation therapy for prostate cancer

    Directory of Open Access Journals (Sweden)

    Wei Gang Wang, MD

    2018-04-01

    Full Text Available Purpose: The purpose of this study is to report the long-term outcomes and toxicity results of a prospective trial of moderately hypofractionated, image guided radiation therapy (RT for localized prostate cancer. Methods and materials: Patients were enrolled between December 2006 and February 2012. Patients in group 1 were stage T1-T2b, had a Gleason score (GS of 2 to 6 or 7 (3 + 4 with only 1 lobe involved, and had prostate-specific antigen levels ≤10 ng/mL. Group 2 patients were stage ≥T2c, had a GS ≥7 (4 + 3, a GS 7 (3 + 4 involving both lobes, or a PSA >10 ng/mL and ≤30 ng/mL. All patients underwent transrectal ultrasound guided fiducial (Visicoil placement prior to computed tomography/magnetic resonance imaging simulation. Daily cone beam computed tomography with online correction was used. The prescribed dose was 64 Gy in 20 fractions. The primary endpoint was acute and late toxicity. The secondary endpoint was biochemical control. Results: A total of 40 patients with a median age of 70 years were recruited for the study. Twenty-two patients (55% were in group 1, and 18 patients (45% were in group 2. Thirteen patients (32.5% were classified as low, 26 patients (65% as intermediate, and 1 patient (2.5% as high risk per the National Comprehensive Cancer Network criteria. The median follow-up time was 59 months. Five-year biochemical control was 100% and 94.4% for groups 1 and 2, respectively. Thirteen patients (32.5% developed acute gastrointestinal (GI toxicities grade ≥2 and 3 (7.5% developed acute grade 3 GI toxicity. A total of 17 patients (42.5% developed grade ≥2 acute genitourinary toxicities and 1 (2.5% developed acute grade 3 dysuria. Two patients (5% developed late GI toxicities grade ≥2. There was 1 case (2.5% of grade 4 fistula requiring sigmoid resection. Seven patients (17.5% developed grade ≥2 late genitourinary toxicities; 2 patients (5% late grade 3 urinary frequency/urgency. Conclusions

  3. SU-F-J-130: Margin Determination for Hypofractionated Partial Breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Geady, C [Ryerson University (Canada); Keller, B; Hahn, E; Vesprini, D; Soliman, H; Lee, J [University of Toronto, Sunnybrook Health Sciences Center, Toronto, Ontario (Canada); Ruschin, M; McCann, C [University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Makhani, N; Bosnic, S [Sunnybrook Health Sciences Center, Toronto, Ontario (Canada)

    2016-06-15

    Purpose: To determine the Planning Target Volume (PTV) margin for Hypofractionated Partial Breast Irradiation (HPBI) using the van Herk formalism (M=2.5∑+0.7σ). HPBI is a novel technique intended to provide local control in breast cancer patients not eligible for surgical resection, using 40 Gy in 5 fractions prescribed to the gross disease. Methods: Setup uncertainties were quantified through retrospective analysis of cone-beam computed tomography (CBCT) data sets, collected prior to (prefraction) and after (postfraction) treatment delivery. During simulation and treatment, patients were immobilized using a wing board and an evacuated bag. Prefraction CBCT was rigidly registered to planning 4-dimensional computed tomography (4DCT) using the chest wall and tumor, and translational couch shifts were applied as needed. This clinical workflow was faithfully reproduced in Pinnacle (Philips Medical Systems) to yield residual setup and intrafractional error through translational shifts and rigid registrations (ribs and sternum) of prefraction CBCT to 4DCT and postfraction CBCT to prefraction CBCT, respectively. All ten patients included in this investigation were medically inoperable; the median age was 84 (range, 52–100) years. Results: Systematic (and random) setup uncertainties (in mm) detected for the left-right, craniocaudal and anteroposterior directions were 0.4 (1.5), 0.8 (1.8) and 0.4 (1.0); net uncertainty was determined to be 0.7 (1.5). Rotations >2° in any axis occurred on 8/72 (11.1%) registrations. Conclusion: Preliminary results suggest a non-uniform setup margin (in mm) of 2.2, 3.3 and 1.7 for the left-right, craniocaudal and anteroposterior directions is required for HPBI, given its immobilization techniques and online setup verification protocol. This investigation is ongoing, though published results from similar studies are consistent with the above findings. Determination of margins in breast radiotherapy is a paradigm shift, but a necessary

  4. Hypofractionated Versus Standard Radiation Therapy With or Without Temozolomide for Older Glioblastoma Patients

    Energy Technology Data Exchange (ETDEWEB)

    Arvold, Nils D. [Department of Radiation Oncology, Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, Massachusetts (United States); Tanguturi, Shyam K. [Harvard Radiation Oncology Program, Boston, Massachusetts (United States); Aizer, Ayal A. [Department of Radiation Oncology, Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, Massachusetts (United States); Wen, Patrick Y.; Reardon, David A.; Lee, Eudocia Q.; Nayak, Lakshmi [Center for Neuro-Oncology, Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, Massachusetts (United States); Christianson, Laura W.; Horvath, Margaret C. [Department of Radiation Oncology, Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, Massachusetts (United States); Dunn, Ian F.; Golby, Alexandra J.; Johnson, Mark D. [Department of Neurosurgery, Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, Massachusetts (United States); Claus, Elizabeth B. [Department of Neurosurgery, Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, Massachusetts (United States); School of Public Health, Yale University, New Haven, Connecticut (United States); Chiocca, E. Antonio [Department of Neurosurgery, Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, Massachusetts (United States); Ligon, Keith L. [Department of Pathology, Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, Massachusetts (United States); Alexander, Brian M., E-mail: bmalexander@lroc.harvard.edu [Department of Radiation Oncology, Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, Massachusetts (United States)

    2015-06-01

    Purpose: Older patients with newly diagnosed glioblastoma have poor outcomes, and optimal treatment is controversial. Hypofractionated radiation therapy (HRT) is frequently used but has not been compared to patients receiving standard fractionated radiation therapy (SRT) and temozolomide (TMZ). Methods and Materials: We conducted a retrospective analysis of patients ≥65 years of age who received radiation for the treatment of newly diagnosed glioblastoma from 1994 to 2013. The distribution of clinical covariates across various radiation regimens was analyzed for possible selection bias. Survival was calculated using the Kaplan-Meier method. Comparison of hypofractionated radiation (typically, 40 Gy/15 fractions) versus standard fractionation (typically, 60 Gy/30 fractions) in the setting of temozolomide was conducted using Cox regression and propensity score analysis. Results: Patients received SRT + TMZ (n=57), SRT (n=35), HRT + TMZ (n=34), or HRT (n=9). Patients receiving HRT were significantly older (median: 79 vs 69 years of age; P<.001) and had worse baseline performance status (P<.001) than those receiving SRT. On multivariate analysis, older age (adjusted hazard ratio [AHR]: 1.06; 95% confidence interval [CI]: 1.01-1.10, P=.01), lower Karnofsky performance status (AHR: 1.02; 95% CI: 1.01-1.03; P=.01), multifocal disease (AHR: 2.11; 95% CI: 1.23-3.61, P=.007), and radiation alone (vs SRT + TMZ; SRT: AHR: 1.72; 95% CI: 1.06-2.79; P=.03; HRT: AHR: 3.92; 95% CI: 1.44-10.60, P=.007) were associated with decreased overall survival. After propensity score adjustment, patients receiving HRT with TMZ had similar overall survival compared with those receiving SRT with TMZ (AHR: 1.10, 95% CI: 0.50-2.4, P=.82). Conclusions: With no randomized data demonstrating equivalence between HRT and SRT in the setting of TMZ for glioblastoma, significant selection bias exists in the implementation of HRT. Controlling for this bias, we observed similar overall

  5. Expert Oracle GoldenGate

    CERN Document Server

    Prusinski, Ben; Chung, Richard

    2011-01-01

    Expert Oracle GoldenGate is a hands-on guide to creating and managing complex data replication environments using the latest in database replication technology from Oracle. GoldenGate is the future in replication technology from Oracle, and aims to be best-of-breed. GoldenGate supports homogeneous replication between Oracle databases. It supports heterogeneous replication involving other brands such as Microsoft SQL Server and IBM DB2 Universal Server. GoldenGate is high-speed, bidirectional, highly-parallelized, and makes only a light impact on the performance of databases involved in replica

  6. Motion management during IMAT treatment of mobile lung tumors-A comparison of MLC tracking and gated delivery

    DEFF Research Database (Denmark)

    Falk, Marianne; Pommer, Tobias; Keall, Paul

    2014-01-01

    Purpose:To compare real-time dynamic multileaf collimator (MLC) tracking, respiratory amplitude and phase gating, and no compensation for intrafraction motion management during intensity modulated arc therapy (IMAT). Methods: Motion management with MLC tracking and gating was evaluated for four...... tracking reduced the effects of the target movements, although the gated delivery showed a better dosimetric accuracy and enabled a larger reduction of the margins in some cases. MLC tracking did not prolong the treatment time compared to delivery with no motion compensation while gating had a considerably...... of the dosimetric error contributions showed that the gated delivery mainly had errors in target localization, while MLC tracking also had contributions from MLC leaf fitting and leaf adjustment. The average treatment time was about three times longer with gating compared to delivery with MLC tracking (that did...

  7. Classical spreading-fractionation, hyperfractionation, hypofractionation: let us attempt to be practical

    International Nuclear Information System (INIS)

    Cosset, J.M.; Baillet, F.

    1986-01-01

    The so-called classical spreading-fractionation (5 sessions of 2 Gy per week) was elaborated originally by the first generation of radiotherapists at the beginning of the century. It is a remarkable fact that even today the most up-to-date radiobiologists are in agreement that this regimen usually represents the best possible compromise between antitumoral efficacy and toxicity to healthy tissue. Hyperfractionation is still in the clinical trial stage with the aim of defining its precise place in clinical practice. At the present there is only one formal indication apart from within this framework: tumors with very rapid times for doubling in size, since hyperfractionation alone can deliver a high dose in a short period of time (accelerated treatment). Hypofractionation can be highly recommended for palliative treatment, because of its simplicity and efficacy. In contrast, when large size tumours (particularly digestive) are treated in patients with an elevated expected rate of recovery, this technique may provoke late complications and should, a priori, be avoided. For small size tumours however (ENT, breast) it would appear possible to elaborate hypofractio - nation protocols allowing local control to a similar degree to that obtained with the classical regimen, without significantly increasing late complications, on the condition that radiation parameters (dose, spread, fractionation) be cho - sen with the greatest care [fr

  8. Hypofractionated Proton Boost Combined with External Beam Radiotherapy for Treatment of Localized Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Silvia Johansson

    2012-01-01

    Full Text Available Proton boost of 20 Gy in daily 5 Gy fractions followed by external beam radiotherapy (EBRT of 50 Gy in daily 2 Gy fractions were given to 278 patients with prostate cancer with T1b to T4N0M0 disease. Fifty-three percent of the patients received neoadjuvant androgen deprivation therapy (N-ADT. The medium followup was 57 months. The 5-year PSA progression-free survival was 100%, 95%, and 74% for low-, intermediate-, and high-risk patients, respectively. The toxicity evaluation was supported by a patient-reported questionnaire before every consultant visit. Cumulative probability and actuarial prevalence of genitourinary (GU and gastrointestinal (GI toxicities are presented according to the RTOG classification. N-ADT did not influence curability. Mild pretreatment GU-symptoms were found to be a strong predictive factor for GU-toxicity attributable to treatment. The actuarial prevalence declined over 3 to 5 years for both GU and GI toxicities, indicating slow resolution of epithelial damage to the genitourinary and gastrointestinal tract. Bladder toxicities rather than gastrointestinal toxicities seem to be dose limiting. More than 5-year followup is necessary to reveal any sign of true progressive late side effects of the given treatment. Hypofractionated proton-boost combined with EBRT is associated with excellent curability of localized PC and acceptable frequencies of treatment toxicity.

  9. Prostate Hypofractionated Radiation Therapy: Injection of Hyaluronic Acid to Better Preserve The Rectal Wall

    International Nuclear Information System (INIS)

    Chapet, Olivier; Udrescu, Corina; Devonec, Marian; Tanguy, Ronan; Sotton, Marie-Pierre; Enachescu, Ciprian; Colombel, Marc; Azria, David; Jalade, Patrice; Ruffion, Alain

    2013-01-01

    Purpose: The aim of this study was to evaluate the contribution of an injection of hyaluronic acid (HA) between the rectum and the prostate for reducing the dose to the rectal wall in a hypofractionated irradiation for prostate cancer. Methods and Materials: In a phase 2 study, 10 cc of HA was injected between the rectum and prostate. For 16 patients, the same intensity modulated radiation therapy plan (62 Gy in 20 fractions) was optimized on 2 computed tomography scans: CT1 (before injection) and CT2 (after injection). Rectal parameters were compared: dose to 2.5 cc (D2.5), 5 cc (D5), 10 cc (D10), 15 cc (D15), and 20 cc (D20) of rectal wall and volume of rectum covered by the 90% isodose line (V90), 80% (V80), 70% (V70), 60% (V60), and 50% (V50). Results: The mean V90, V80, V70, V60, and V50 values were reduced by 73.8% (P<.0001), 55.7% (P=.0003), 43.0% (P=.007), 34% (P=.002), and 25% (P=.036), respectively. The average values of D2.5, D5, D10, D15, and D20 were reduced by 8.5 Gy (P<.0001), 12.3 Gy (P<.0001), 8.4 Gy (P=.005), 3.7 Gy (P=.026), and 1.2 Gy (P=.25), respectively. Conclusions: The injection of HA significantly limited radiation doses to the rectal wall

  10. Prostate Hypofractionated Radiation Therapy: Injection of Hyaluronic Acid to Better Preserve The Rectal Wall

    Energy Technology Data Exchange (ETDEWEB)

    Chapet, Olivier, E-mail: olivier.chapet@chu-lyon.fr [Department of Radiation Oncology, Centre Hospitalier Lyon Sud, Pierre Benite (France); Udrescu, Corina [Department of Radiation Oncology, Centre Hospitalier Lyon Sud, Pierre Benite (France); Department of Medical Physics, Centre Hospitalier Lyon Sud, Pierre Benite (France); Devonec, Marian [Department of Urology, Centre Hospitalier Lyon Sud, Pierre Benite (France); Tanguy, Ronan [Department of Radiation Oncology, Centre Hospitalier Lyon Sud, Pierre Benite (France); Sotton, Marie-Pierre [Department of Medical Physics, Centre Hospitalier Lyon Sud, Pierre Benite (France); Enachescu, Ciprian [Department of Radiation Oncology, Centre Hospitalier Lyon Sud, Pierre Benite (France); Colombel, Marc [Department of Urology, Hopital Edouard Herriot, Lyon (France); Azria, David [Department of Radiation Oncology, Centre Val d' Aurelle, Montpellier (France); Jalade, Patrice [Department of Medical Physics, Centre Hospitalier Lyon Sud, Pierre Benite (France); Ruffion, Alain [Department of Urology, Centre Hospitalier Lyon Sud, Pierre Benite (France)

    2013-05-01

    Purpose: The aim of this study was to evaluate the contribution of an injection of hyaluronic acid (HA) between the rectum and the prostate for reducing the dose to the rectal wall in a hypofractionated irradiation for prostate cancer. Methods and Materials: In a phase 2 study, 10 cc of HA was injected between the rectum and prostate. For 16 patients, the same intensity modulated radiation therapy plan (62 Gy in 20 fractions) was optimized on 2 computed tomography scans: CT1 (before injection) and CT2 (after injection). Rectal parameters were compared: dose to 2.5 cc (D2.5), 5 cc (D5), 10 cc (D10), 15 cc (D15), and 20 cc (D20) of rectal wall and volume of rectum covered by the 90% isodose line (V90), 80% (V80), 70% (V70), 60% (V60), and 50% (V50). Results: The mean V90, V80, V70, V60, and V50 values were reduced by 73.8% (P<.0001), 55.7% (P=.0003), 43.0% (P=.007), 34% (P=.002), and 25% (P=.036), respectively. The average values of D2.5, D5, D10, D15, and D20 were reduced by 8.5 Gy (P<.0001), 12.3 Gy (P<.0001), 8.4 Gy (P=.005), 3.7 Gy (P=.026), and 1.2 Gy (P=.25), respectively. Conclusions: The injection of HA significantly limited radiation doses to the rectal wall.

  11. The effect of hypofractionated radiation and magnetic nanoparticle hyperthermia on tumor immunogenicity and overall treatment response

    Science.gov (United States)

    Hoopes, P. Jack; Wagner, Robert J.; Song, Ailin; Osterberg, Bjorn; Gladstone, David J.; Bursey, Alicea A.; Fiering, Steven N.; Giustini, Andrew J.

    2017-02-01

    It is now known that many tumors develop molecular signals (immune checkpoint modulators) that inhibit an effective tumor immune response. New information also suggest that even well-known cancer treatment modalities such as radiation and hyperthermia generate potentially beneficial immune responses that have been blocked or mitigated by such immune checkpoints, or similar molecules. The cancer therapy challenge is to; a) identify these treatment-based immune signals (proteins, antigens, etc.); b) the treatment doses or regimens that produce them; and c) the mechanisms that block or have the potential to promote them. The goal of this preliminary study, using the B6 mouse - B16 tumor model, clinically relevant radiation doses and fractionation schemes (including those used clinically in hypofractionated radiation therapy), magnetic nanoparticle hyperthermia (mNPH) and sophisticated protein, immune and tumor growth analysis techniques and modulators, is to determine the effect of specific radiation or hyperthermia alone and combined on overall treatment efficacy and immunologic response mechanisms. Preliminary analysis suggests that radiation dose (10 Gy vs. 2 Gy) significantly alters the mechanism of cell death (apoptosis vs. mitosis vs. necrosis) and the resulting immunogenicity. Our hypothesis and data suggest this difference is protein/antigen and immune recognition-based. Similarly, our evidence suggest that radiation doses larger than the conventional 2 Gy dose and specific hyperthermia doses and techniques (including mNP hyperthermia treatment) can be immunologically different, and potentially superior to, the radiation and heat therapy regimens that are typically used in research and clinical practice.

  12. Reirradiation of head and neck cancer focusing on hypofractionated stereotactic body radiation therapy

    International Nuclear Information System (INIS)

    Yamazaki, Hideya; Kodani, Naohiro; Ogita, Mikio; Sato, Kengo; Himei, Kengo

    2011-01-01

    Reirradiation is a feasible option for patients who do not otherwise have treatment options available. Depending on the location and extent of the tumor, reirradiation may be accomplished with external beam radiotherapy, brachytherapy, radiosurgery, or intensity modulated radiation therapy (IMRT). Although there has been limited experience with hypofractionated stereotactic radiotherapy (hSRT), it may have the potential for curative or palliative treatment due to its advanced precision technology, particularly for limited small lesion. On the other hand, severe late adverse reactions are anticipated with reirradiation than with initial radiation therapy. The risk of severe late complications has been reported to be 20- 40% and is related to prior radiotherapy dose, primary site, retreatment radiotherapy dose, treatment volume, and technique. Early researchers have observed lethal bleeding in such patients up to a rate of 14%. Recently, similar rate of 10-15% was observed for fatal bleeding with use of modern hSRT like in case of carotid blowout syndrome. To determine the feasibility and efficacy of reirradiation using modern technology, we reviewed the pertinent literature. The potentially lethal side effects should be kept in mind when reirradiation by hSRT is considered for treatment, and efforts should be made to minimize the risk in any future investigations

  13. Hypofractionated Proton Boost Combined with External Beam Radiotherapy for Treatment of Localized Prostate Cancer

    Science.gov (United States)

    Johansson, Silvia; Åström, Lennart; Sandin, Fredrik; Isacsson, Ulf; Montelius, Anders; Turesson, Ingela

    2012-01-01

    Proton boost of 20 Gy in daily 5 Gy fractions followed by external beam radiotherapy (EBRT) of 50 Gy in daily 2 Gy fractions were given to 278 patients with prostate cancer with T1b to T4N0M0 disease. Fifty-three percent of the patients received neoadjuvant androgen deprivation therapy (N-ADT). The medium followup was 57 months. The 5-year PSA progression-free survival was 100%, 95%, and 74% for low-, intermediate-, and high-risk patients, respectively. The toxicity evaluation was supported by a patient-reported questionnaire before every consultant visit. Cumulative probability and actuarial prevalence of genitourinary (GU) and gastrointestinal (GI) toxicities are presented according to the RTOG classification. N-ADT did not influence curability. Mild pretreatment GU-symptoms were found to be a strong predictive factor for GU-toxicity attributable to treatment. The actuarial prevalence declined over 3 to 5 years for both GU and GI toxicities, indicating slow resolution of epithelial damage to the genitourinary and gastrointestinal tract. Bladder toxicities rather than gastrointestinal toxicities seem to be dose limiting. More than 5-year followup is necessary to reveal any sign of true progressive late side effects of the given treatment. Hypofractionated proton-boost combined with EBRT is associated with excellent curability of localized PC and acceptable frequencies of treatment toxicity. PMID:22848840

  14. Reirradiation of head and neck cancer focusing on hypofractionated stereotactic body radiation therapy

    Directory of Open Access Journals (Sweden)

    Ogita Mikio

    2011-08-01

    Full Text Available Abstract Reirradiation is a feasible option for patients who do not otherwise have treatment options available. Depending on the location and extent of the tumor, reirradiation may be accomplished with external beam radiotherapy, brachytherapy, radiosurgery, or intensity modulated radiation therapy (IMRT. Although there has been limited experience with hypofractionated stereotactic radiotherapy (hSRT, it may have the potential for curative or palliative treatment due to its advanced precision technology, particularly for limited small lesion. On the other hand, severe late adverse reactions are anticipated with reirradiation than with initial radiation therapy. The risk of severe late complications has been reported to be 20- 40% and is related to prior radiotherapy dose, primary site, retreatment radiotherapy dose, treatment volume, and technique. Early researchers have observed lethal bleeding in such patients up to a rate of 14%. Recently, similar rate of 10-15% was observed for fatal bleeding with use of modern hSRT like in case of carotid blowout syndrome. To determine the feasibility and efficacy of reirradiation using modern technology, we reviewed the pertinent literature. The potentially lethal side effects should be kept in mind when reirradiation by hSRT is considered for treatment, and efforts should be made to minimize the risk in any future investigations.

  15. Quad shot - hypofractionated radiotherapy for palliation in advanced squamous cell carcinoma of head and neck

    International Nuclear Information System (INIS)

    Maqsood, T.; Ali, U.; Arif, S.

    2017-01-01

    The objective of this study was to determine the efficacy of quad-shot radiation therapy for palliation in locally advanced and metastatic inoperable squamous cell carcinomas of head and neck. Study Design: A quasi-experimental study. Place and Duration of Study: Oncology department, Combined Military Hospital Rawalpindi, from Sep 2012 to Sep 2013. Material and Methods: Thirty five patients were included with histologically confirmed advanced inoperable squamous cell carcinoma in head and neck region, performance status 2 or 3 and survival =3 months. Patients were treated with radiation therapy 14 Gy in four fractions, megavoltage beam, twice daily fractions (at least 6 hours apart), for 2 consecutive days. Symptoms due to cancer (pain and dysphagia) were assessed as per common toxicity criteria adverse event version 4.0 on day 0 before treatment and day 21 after start of treatment. Results: Grades of pain and dysphagia showed significant improvement after treatment with a p-value <0.001. A total of 91.4% patients showed an improvement in grade of pain (32 out of 35 patients) and 45.7% of patients showed improvement in grade of dysphagia (16 out of 35 patients). There was a statistically significant decrease in grades of pain and dysphagia after treatment. Conclusion: The short duration of hypofractionated radiotherapy with Quad Shot was effective with respect to symptom palliation in locally advanced and metastatic inoperable head and neck cancers.

  16. Hypofractionated High-Dose Irradiation with Positron Emission Tomography Data for the Treatment of Glioblastoma Multiforme

    Directory of Open Access Journals (Sweden)

    Kazuhiro Miwa

    2014-01-01

    Full Text Available This research paper presents clinical outcomes of hypofractionated high-dose irradiation by intensity-modulated radiation therapy (Hypo-IMRT with 11C-methionine positron emission tomography (MET-PET data for the treatment of glioblastoma multiforme (GBM. A total of 45 patients with GBM were treated with Hypo-IMRT after surgery. Gross tumor volume (GTV was defined as the area of enhanced lesion on MRI, including MET-PET avid region; clinical target volume (CTV was the area with 5 mm margin surrounding the GTV; planning target volume (PTV was the area with 15 mm margin surrounding the CTV, including MET-PET moderate region. Hypo-IMRT was performed in 8 fractions; planning the dose for GTV was escalated to 68 Gy and that for CTV was escalated to 56 Gy, while keeping the dose delivered to the PTV at 40 Gy. Concomitant and adjuvant TMZ chemotherapy was administered. At a median follow-up of 18.7 months, median overall survival (OS was 20.0 months, and median progression-free survival was 13.0 months. The 1- and 2-year OS rates were 71.2% and 26.3%, respectively. Adjuvant TMZ chemotherapy was significantly predictive of OS on multivariate analysis. Late toxicity included 7 cases of Grade 3-4 radiation necrosis. Hypo-IMRT with MET-PET data appeared to result in favorable survival outcomes for patients with GBM.

  17. Hypofractionated radiation therapy in the treatment of epidemic Kaposi sarcoma - A prospective randomized trial

    International Nuclear Information System (INIS)

    Singh, Niveditha B.; Lakier, Roy H.; Donde, Bernard

    2008-01-01

    Purpose: To compare a conventional fractionation regimen with a hypofractionated regimen in the treatment of Epidemic Kaposi sarcoma with radiation therapy. Materials and methods: Sixty patients were randomized to receive a standard regimen of 24 Gy in 12 fractions (ARM A) or the study regimen of 20 Gy in five fractions (ARM B). Radiation technique was individualized. Treatment response, local control and toxicity were recorded. Results: Thirty five sites were treated in ARM A and 30 sites in ARM B. Treatment arms were similar for gender, ECOG performance score, treated site, antiretroviral therapy usage, T stage, I stage and S stage. The overall survival using the Kaplan Meier method was 37% at 1 year. Complete responses were recorded at 28 sites (13 Arm A, 15 Arm B), partial responses at 19 sites (8 Arm A, 11 Arm B) and stable disease at three sites (2 Arm A, 1 Arm B). The mean time to maximum objective response was 3 months (range: 1-14 months). Response rates and local control were equal in the two arms (p = 0.73 and 0.77, respectively, log rank test). Acute skin toxicity (p = 0.77) and late skin toxicity (p = 0.24) were equal in the two arms. Conclusion: The two treatment regimens produced equivalent results for treatment response, local recurrence-free survival and toxicity

  18. Extracranial Facial Nerve Schwannoma Treated by Hypo-fractionated CyberKnife Radiosurgery.

    Science.gov (United States)

    Sasaki, Ayaka; Miyazaki, Shinichiro; Hori, Tomokatsu

    2016-09-21

    Facial nerve schwannoma is a rare intracranial tumor. Treatment for this benign tumor has been controversial. Here, we report a case of extracranial facial nerve schwannoma treated successfully by hypo-fractionated CyberKnife (Accuray, Sunnyvale, CA) radiosurgery and discuss the efficacy of this treatment. A 34-year-old female noticed a swelling in her right mastoid process. The lesion enlarged over a seven-month period, and she experienced facial spasm on the right side. She was diagnosed with a facial schwannoma via a magnetic resonance imaging (MRI) scan of the head and neck and was told to wait until the facial nerve palsy subsides. She was referred to our hospital for radiation therapy. We planned a fractionated CyberKnife radiosurgery for three consecutive days. After CyberKnife radiosurgery, the mass in the right parotid gradually decreased in size, and the facial nerve palsy disappeared. At her eight-month follow-up, her facial spasm had completely disappeared. There has been no recurrence and the facial nerve function has been normal. We successfully demonstrated the efficacy of CyberKnife radiosurgery as an alternative treatment that also preserves neurofunction for facial nerve schwannomas.

  19. Enhancing ejection fraction measurement through 4D respiratory motion compensation in cardiac PET imaging

    Science.gov (United States)

    Tang, Jing; Wang, Xinhui; Gao, Xiangzhen; Segars, W. Paul; Lodge, Martin A.; Rahmim, Arman

    2017-06-01

    ECG gated cardiac PET imaging measures functional parameters such as left ventricle (LV) ejection fraction (EF), providing diagnostic and prognostic information for management of patients with coronary artery disease (CAD). Respiratory motion degrades spatial resolution and affects the accuracy in measuring the LV volumes for EF calculation. The goal of this study is to systematically investigate the effect of respiratory motion correction on the estimation of end-diastolic volume (EDV), end-systolic volume (ESV), and EF, especially on the separation of normal and abnormal EFs. We developed a respiratory motion incorporated 4D PET image reconstruction technique which uses all gated-frame data to acquire a motion-suppressed image. Using the standard XCAT phantom and two individual-specific volunteer XCAT phantoms, we simulated dual-gated myocardial perfusion imaging data for normally and abnormally beating hearts. With and without respiratory motion correction, we measured the EDV, ESV, and EF from the cardiac-gated reconstructed images. For all the phantoms, the estimated volumes increased and the biases significantly reduced with motion correction compared with those without. Furthermore, the improvement of ESV measurement in the abnormally beating heart led to better separation of normal and abnormal EFs. The simulation study demonstrated the significant effect of respiratory motion correction on cardiac imaging data with motion amplitude as small as 0.7 cm. The larger the motion amplitude the more improvement respiratory motion correction brought about on the EF measurement. Using data-driven respiratory gating, we also demonstrated the effect of respiratory motion correction on estimating the above functional parameters from list mode patient data. Respiratory motion correction has been shown to improve the accuracy of EF measurement in clinical cardiac PET imaging.

  20. A novel optical gating method for laser gated imaging

    Science.gov (United States)

    Ginat, Ran; Schneider, Ron; Zohar, Eyal; Nesher, Ofer

    2013-06-01

    For the past 15 years, Elbit Systems is developing time-resolved active laser-gated imaging (LGI) systems for various applications. Traditional LGI systems are based on high sensitive gated sensors, synchronized to pulsed laser sources. Elbit propriety multi-pulse per frame method, which is being implemented in LGI systems, improves significantly the imaging quality. A significant characteristic of the LGI is its ability to penetrate a disturbing media, such as rain, haze and some fog types. Current LGI systems are based on image intensifier (II) sensors, limiting the system in spectral response, image quality, reliability and cost. A novel propriety optical gating module was developed in Elbit, untying the dependency of LGI system on II. The optical gating module is not bounded to the radiance wavelength and positioned between the system optics and the sensor. This optical gating method supports the use of conventional solid state sensors. By selecting the appropriate solid state sensor, the new LGI systems can operate at any desired wavelength. In this paper we present the new gating method characteristics, performance and its advantages over the II gating method. The use of the gated imaging systems is described in a variety of applications, including results from latest field experiments.

  1. Penn State DOE GATE Program

    Energy Technology Data Exchange (ETDEWEB)

    Anstrom, Joel

    2012-08-31

    The Graduate Automotive Technology Education (GATE) Program at The Pennsylvania State University (Penn State) was established in October 1998 pursuant to an award from the U.S. Department of Energy (U.S. DOE). The focus area of the Penn State GATE Program is advanced energy storage systems for electric and hybrid vehicles.

  2. Piezoconductivity of gated suspended graphene

    NARCIS (Netherlands)

    Medvedyeva, M.V.; Blanter, Y.M.

    2011-01-01

    We investigate the conductivity of graphene sheet deformed over a gate. The effect of the deformation on the conductivity is twofold: The lattice distortion can be represented as pseudovector potential in the Dirac equation formalism, whereas the gate causes inhomogeneous density redistribution. We

  3. Measurement of time delay for a prospectively gated CT simulator.

    Science.gov (United States)

    Goharian, M; Khan, R F H

    2010-04-01

    For the management of mobile tumors, respiratory gating is the ideal option, both during imaging and during therapy. The major advantage of respiratory gating during imaging is that it is possible to create a single artifact-free CT data-set during a selected phase of the patient's breathing cycle. The purpose of the present work is to present a simple technique to measure the time delay during acquisition of a prospectively gated CT. The time delay of a Philips Brilliance BigBore (Philips Medical Systems, Madison, WI) scanner attached to a Varian Real-Time Position Management (RPM) system (Varian Medical Systems, Palo Alto, CA) was measured. Two methods were used to measure the CT time delay: using a motion phantom and using a recorded data file from the RPM system. In the first technique, a rotating wheel phantom was altered by placing two plastic balls on its axis and rim, respectively. For a desired gate, the relative positions of the balls were measured from the acquired CT data and converted into corresponding phases. Phase difference was calculated between the measured phases and the desired phases. Using period of motion, the phase difference was converted into time delay. The Varian RPM system provides an external breathing signal; it also records transistor-transistor logic (TTL) 'X-Ray ON' status signal from the CT scanner in a text file. The TTL 'X-Ray ON' indicates the start of CT image acquisition. Thus, knowledge of the start time of CT acquisition, combined with the real-time phase and amplitude data from the external respiratory signal, provides time-stamping of all images in an axial CT scan. The TTL signal with time-stamp was used to calculate when (during the breathing cycle) a slice was recorded. Using the two approaches, the time delay between the prospective gating signal and CT simulator has been determined to be 367 +/- 40 ms. The delay requires corrections both at image acquisition and while setting gates for the treatment delivery

  4. Measurement of time delay for a prospectively gated CT simulator

    Directory of Open Access Journals (Sweden)

    Goharian M

    2010-01-01

    Full Text Available For the management of mobile tumors, respiratory gating is the ideal option, both during imaging and during therapy. The major advantage of respiratory gating during imaging is that it is possible to create a single artifact-free CT data-set during a selected phase of the patient′s breathing cycle. The purpose of the present work is to present a simple technique to measure the time delay during acquisition of a prospectively gated CT. The time delay of a Philips Brilliance BigBore™ (Philips Medical Systems, Madison, WI scanner attached to a Varian Real-Time Position Management™ (RPM system (Varian Medical Systems, Palo Alto, CA was measured. Two methods were used to measure the CT time delay: using a motion phantom and using a recorded data file from the RPM system. In the first technique, a rotating wheel phantom was altered by placing two plastic balls on its axis and rim, respectively. For a desired gate, the relative positions of the balls were measured from the acquired CT data and converted into corresponding phases. Phase difference was calculated between the measured phases and the desired phases. Using period of motion, the phase difference was converted into time delay. The Varian RPM system provides an external breathing signal; it also records transistor-transistor logic (TTL ′X-Ray ON′ status signal from the CT scanner in a text file. The TTL ′X-Ray ON′ indicates the start of CT image acquisition. Thus, knowledge of the start time of CT acquisition, combined with the real-time phase and amplitude data from the external respiratory signal, provides time-stamping of all images in an axial CT scan. The TTL signal with time-stamp was used to calculate when (during the breathing cycle a slice was recorded. Using the two approaches, the time delay between the prospective gating signal and CT simulator has been determined to be 367 ± 40 ms. The delay requires corrections both at image acquisition and while setting gates for

  5. Measurement of time delay for a prospectively gated CT simulator

    International Nuclear Information System (INIS)

    Goharian, M.; Khan, R.F.H.

    2010-01-01

    For the management of mobile tumors, respiratory gating is the ideal option, both during imaging and during therapy. The major advantage of respiratory gating during imaging is that it is possible to create a single artifact-free CT data-set during a selected phase of the patient's breathing cycle. The purpose of the present work is to present a simple technique to measure the time delay during acquisition of a prospectively gated CT. The time delay of a Philips Brilliance BigBore (Philips Medical Systems, Madison, WI) scanner attached to a Varian Real-Time Position Management (RPM) system (Varian Medical Systems, Palo Alto, CA) was measured. Two methods were used to measure the CT time delay: using a motion phantom and using a recorded data file from the RPM system. In the first technique, a rotating wheel phantom was altered by placing two plastic balls on its axis and rim, respectively. For a desired gate, the relative positions of the balls were measured from the acquired CT data and converted into corresponding phases. Phase difference was calculated between the measured phases and the desired phases. Using period of motion, the phase difference was converted into time delay. The Varian RPM system provides an external breathing signal; it also records transistor-transistor logic (TTL) 'X-Ray ON' status signal from the CT scanner in a text file. The TTL 'X-Ray ON' indicates the start of CT image acquisition. Thus, knowledge of the start time of CT acquisition, combined with the real-time phase and amplitude data from the external respiratory signal, provides time-stamping of all images in an axial CT scan. The TTL signal with time-stamp was used to calculate when (during the breathing cycle) a slice was recorded. Using the two approaches, the time delay between the prospective gating signal and CT simulator has been determined to be 367 ± 40 ms. The delay requires corrections both at image acquisition and while setting gates for the treatment delivery

  6. Impact of Fraction Size on Lung Radiation Toxicity: Hypofractionation may be Beneficial in Dose Escalation of Radiotherapy for Lung Cancers

    International Nuclear Information System (INIS)

    Jin Jinyue; Kong Fengming; Chetty, Indrin J.; Ajlouni, Munther; Ryu, Samuel; Ten Haken, Randall; Movsas, Benjamin

    2010-01-01

    Purpose: To assess how fraction size impacts lung radiation toxicity and therapeutic ratio in treatment of lung cancers. Methods and Materials: The relative damaged volume (RDV) of lung was used as the endpoint in the comparison of various fractionation schemes with the same normalized total dose (NTD) to the tumor. The RDV was computed from the biologically corrected lung dose-volume histogram (DVH), with an α/β ratio of 3 and 10 for lung and tumor, respectively. Two different (linear and S-shaped) local dose-effect models that incorporated the concept of a threshold dose effect with a single parameter D L50 (dose at 50% local dose effect) were used to convert the DVH into the RDV. The comparison was conducted using four representative DVHs at different NTD and D L50 values. Results: The RDV decreased with increasing dose/fraction when the NTD was larger than a critical dose (D CR ) and increased when the NTD was less than D CR . The D CR was 32-50 Gy and 58-87 Gy for a small tumor (11 cm 3 ) for the linear and S-shaped local dose-effect models, respectively, when D L50 was 20-30 Gy. The D CR was 66-97 Gy and 66-99 Gy, respectively, for a large tumor (266 cm 3 ). Hypofractionation was preferred for small tumors and higher NTDs, and conventional fractionation was better for large tumors and lower NTDs. Hypofractionation might be beneficial for intermediate-sized tumors when NTD = 80-90 Gy, especially if the D L50 is small (20 Gy). Conclusion: This computational study demonstrated that hypofractionated stereotactic body radiotherapy is a better regimen than conventional fractionation in lung cancer patients with small tumors and high doses, because it generates lower RDV when the tumor NTD is kept unchanged.

  7. A Phase 2 Trial of Once-Weekly Hypofractionated Breast Irradiation: First Report of Acute Toxicity, Feasibility, and Patient Satisfaction

    Energy Technology Data Exchange (ETDEWEB)

    Dragun, Anthony E., E-mail: aedrag01@louisville.edu [Department of Radiation Oncology, University of Louisville School of Medicine, James Graham Brown Cancer Center, Louisville, Kentucky (United States); Quillo, Amy R. [Department of Surgical Oncology, University of Louisville School of Medicine, James Graham Brown Cancer Center, Louisville, Kentucky (United States); Riley, Elizabeth C. [Department of Medical Oncology, University of Louisville School of Medicine, James Graham Brown Cancer Center, Louisville, Kentucky (United States); Roberts, Teresa L.; Hunter, Allison M. [Department of Radiation Oncology, University of Louisville School of Medicine, James Graham Brown Cancer Center, Louisville, Kentucky (United States); Rai, Shesh N. [Department of Biostatistics and Epidemiology, University of Louisville School of Medicine, James Graham Brown Cancer Center, Louisville, Kentucky (United States); Callender, Glenda G. [Department of Surgical Oncology, University of Louisville School of Medicine, James Graham Brown Cancer Center, Louisville, Kentucky (United States); Jain, Dharamvir [Department of Medical Oncology, University of Louisville School of Medicine, James Graham Brown Cancer Center, Louisville, Kentucky (United States); McMasters, Kelly M. [Department of Surgical Oncology, University of Louisville School of Medicine, James Graham Brown Cancer Center, Louisville, Kentucky (United States); Spanos, William J. [Department of Radiation Oncology, University of Louisville School of Medicine, James Graham Brown Cancer Center, Louisville, Kentucky (United States)

    2013-03-01

    Purpose: To report on early results of a single-institution phase 2 trial of a 5-fraction, once-weekly radiation therapy regimen for patients undergoing breast-conserving surgery (BCS). Methods and Materials: Patients who underwent BCS for American Joint Committee on Cancer stage 0, I, or II breast cancer with negative surgical margins were eligible to receive whole breast radiation therapy to a dose of 30 Gy in 5 weekly fractions of 6 Gy with or without an additional boost. Elective nodal irradiation was not permitted. There were no restrictions on breast size or the use of cytotoxic chemotherapy for otherwise eligible patients. Patients were assessed at baseline, treatment completion, and at first posttreatment follow-up to assess acute toxicity (Common Terminology Criteria for Adverse Events, version 3.0) and quality of life (European Organization for Research and Treatment of Cancer QLQ-BR23). Results: Between January and September 2011, 42 eligible patients underwent weekly hypofractionated breast irradiation immediately following BCS (69.0%) or at the conclusion of cytotoxic chemotherapy (31.0%). The rates of grade ≥2 radiation-induced dermatitis, pain, fatigue, and breast edema were 19.0%, 11.9%, 9.5%, and 2.4%, respectively. Only 1 grade 3 toxicity—pain requiring a course of narcotic analgesics—was observed. One patient developed a superficial cellulitis (grade 2), which resolved with the use of oral antibiotics. Patient-reported moderate-to-major breast symptoms (pain, swelling, and skin problems), all decreased from baseline through 1 month, whereas breast sensitivity remained stable over the study period. Conclusions: The tolerance of weekly hypofractionated breast irradiation compares well with recent reports of daily hypofractionated whole-breast irradiation schedules. The regimen appears feasible and cost-effective. Additional follow-up with continued accrual is needed to assess late toxicity, cosmesis, and disease-specific outcomes.

  8. A Phase 2 Trial of Once-Weekly Hypofractionated Breast Irradiation: First Report of Acute Toxicity, Feasibility, and Patient Satisfaction

    International Nuclear Information System (INIS)

    Dragun, Anthony E.; Quillo, Amy R.; Riley, Elizabeth C.; Roberts, Teresa L.; Hunter, Allison M.; Rai, Shesh N.; Callender, Glenda G.; Jain, Dharamvir; McMasters, Kelly M.; Spanos, William J.

    2013-01-01

    Purpose: To report on early results of a single-institution phase 2 trial of a 5-fraction, once-weekly radiation therapy regimen for patients undergoing breast-conserving surgery (BCS). Methods and Materials: Patients who underwent BCS for American Joint Committee on Cancer stage 0, I, or II breast cancer with negative surgical margins were eligible to receive whole breast radiation therapy to a dose of 30 Gy in 5 weekly fractions of 6 Gy with or without an additional boost. Elective nodal irradiation was not permitted. There were no restrictions on breast size or the use of cytotoxic chemotherapy for otherwise eligible patients. Patients were assessed at baseline, treatment completion, and at first posttreatment follow-up to assess acute toxicity (Common Terminology Criteria for Adverse Events, version 3.0) and quality of life (European Organization for Research and Treatment of Cancer QLQ-BR23). Results: Between January and September 2011, 42 eligible patients underwent weekly hypofractionated breast irradiation immediately following BCS (69.0%) or at the conclusion of cytotoxic chemotherapy (31.0%). The rates of grade ≥2 radiation-induced dermatitis, pain, fatigue, and breast edema were 19.0%, 11.9%, 9.5%, and 2.4%, respectively. Only 1 grade 3 toxicity—pain requiring a course of narcotic analgesics—was observed. One patient developed a superficial cellulitis (grade 2), which resolved with the use of oral antibiotics. Patient-reported moderate-to-major breast symptoms (pain, swelling, and skin problems), all decreased from baseline through 1 month, whereas breast sensitivity remained stable over the study period. Conclusions: The tolerance of weekly hypofractionated breast irradiation compares well with recent reports of daily hypofractionated whole-breast irradiation schedules. The regimen appears feasible and cost-effective. Additional follow-up with continued accrual is needed to assess late toxicity, cosmesis, and disease-specific outcomes

  9. Lyman NTCP model analysis of radiation-induced liver disease in hypofractionated conformal radiotherapy for primary liver carcinoma

    International Nuclear Information System (INIS)

    Xu Zhiyong; Zhu Yi; Zhao Jiaodong; Fu Xiaolong; Jiang Guoliang; Liang Shixiong; Zhu Xiaodong

    2006-01-01

    Objective: To identify the factors associated with radiation-induced liver disease (RILD) and to describe the probability of RILD using the Lyman normal tissue complication(NTCP) model for primary liver carcinoma(PLC) treated with hypofractionated conformal therapy (CRT). Methods: A total of 109 PLC patients treated with hypofractionated CRT were prospectively followed according to the Child-Pugh classification for liver cirrhosis, 93 patients in class A and 16 in class B. The mean dose of radiation to the isocenter was (53.5±5.5) Gy, fractions of (4.8±0.5) Gy, with interfraction interval of 48 hours and irradiation 3 times per week. Maximal likelihood analysis yielded the best estimates of parameters of the Lyman NTCP model for all patients; Child-Pugh A and Child-Pugh B patients, respectively. Results: Of all the patients, 17 developed RILD (17/109), 8 in Child-Pugh A (8/93) and 9 in Child-Pugh B (9/16). By multivariate analysis, only the Child-Pugh Grade of liver cirrhosis was the independent factor (P=0.000) associated with the developing of BILD. The best estimates of the NTCP parameters for all 109 patients were n=1.1, m=0.35 and TD 50 (1)=38.5 Gy. The n, m, TD 50 (1) estimated from patients with Child-Pugh A was 1.1, 0.28, 40.5 Gy, respectively, compared with 0.7, 0.43, 23 Gy respectively, for patients with Child-Pugh B. Conclusions: Primary liver cancer patients who possess Child-Pugh B cirrhosis would present a significantly greater susceptibility to RILD after hypofractionated CRT than patients with Child-Pugh A cirrhosis. The predominant risk factor for developing RILD is the severity of hepatic cirrhosis in the liver of PLC patients. (authors)

  10. SU-E-T-776: Use of Quality Metrics for a New Hypo-Fractionated Pre-Surgical Mesothelioma Protocol

    International Nuclear Information System (INIS)

    Richardson, S; Mehta, V

    2015-01-01

    Purpose: The “SMART” (Surgery for Mesothelioma After Radiation Therapy) approach involves hypo-fractionated radiotherapy of the lung pleura to 25Gy over 5 days followed by surgical resection within 7. Early clinical results suggest that this approach is very promising, but also logistically challenging due to the multidisciplinary involvement. Due to the compressed schedule, high dose, and shortened planning time, the delivery of the planned doses were monitored for safety with quality metric software. Methods: Hypo-fractionated IMRT treatment plans were developed for all patients and exported to Quality Reports™ software. Plan quality metrics or PQMs™ were created to calculate an objective scoring function for each plan. This allows for an objective assessment of the quality of the plan and a benchmark for plan improvement for subsequent patients. The priorities of various components were incorporated based on similar hypo-fractionated protocols such as lung SBRT treatments. Results: Five patients have been treated at our institution using this approach. The plans were developed, QA performed, and ready within 5 days of simulation. Plan Quality metrics utilized in scoring included doses to OAR and target coverage. All patients tolerated treatment well and proceeded to surgery as scheduled. Reported toxicity included grade 1 nausea (n=1), grade 1 esophagitis (n=1), grade 2 fatigue (n=3). One patient had recurrent fluid accumulation following surgery. No patients experienced any pulmonary toxicity prior to surgery. Conclusion: An accelerated course of pre-operative high dose radiation for mesothelioma is an innovative and promising new protocol. Without historical data, one must proceed cautiously and monitor the data carefully. The development of quality metrics and scoring functions for these treatments allows us to benchmark our plans and monitor improvement. If subsequent toxicities occur, these will be easy to investigate and incorporate into the

  11. Individualized Dose Prescription for Hypofractionation in Advanced Non-Small-Cell Lung Cancer Radiotherapy: An in silico Trial

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Aswin L.; Troost, Esther G.C.; Huizenga, Henk; Kaanders, Johannes H.A.M. [Radboud University Nijmegen Medical Centre, Department of Radiation Oncology, Nijmegen (Netherlands); Bussink, Johan, E-mail: j.bussink@rther.umcn.nl [Radboud University Nijmegen Medical Centre, Department of Radiation Oncology, Nijmegen (Netherlands)

    2012-08-01

    Purpose: Local tumor control and outcome remain poor in patients with advanced non-small-cell lung cancer (NSCLC) treated by external beam radiotherapy. We investigated the therapeutic gain of individualized dose prescription with dose escalation based on normal tissue dose constraints for various hypofractionation schemes delivered with intensity-modulated radiation therapy. Methods and Materials: For 38 Stage III NSCLC patients, the dose level of an existing curative treatment plan with standard fractionation (66 Gy) was rescaled based on dose constraints for the lung, spinal cord, esophagus, brachial plexus, and heart. The effect on tumor total dose (TTD) and biologic tumor effective dose in 2-Gy fractions (TED) corrected for overall treatment time (OTT) was compared for isotoxic and maximally tolerable schemes given in 15, 20, and 33 fractions. Rescaling was accomplished by altering the dose per fraction and/or the number of fractions while keeping the relative dose distribution of the original treatment plan. Results: For 30 of the 38 patients, dose escalation by individualized hypofractionation yielded therapeutic gain. For the maximally tolerable dose scheme in 33 fractions (MTD{sub 33}), individualized dose escalation resulted in a 2.5-21% gain in TTD. In the isotoxic schemes, the number of fractions could be reduced with a marginal increase in TED. For the maximally tolerable dose schemes, the TED could be escalated up to 36.6%, and for all patients beyond the level of the isotoxic and the MTD{sub 33} schemes (range, 3.3-36.6%). Reduction of the OTT contributed to the therapeutic gain of the shortened schemes. For the maximally tolerable schemes, the maximum esophageal dose was the dominant dose-limiting constraint in most patients. Conclusions: This modeling study showed that individualized dose prescription for hypofractionation in NSCLC radiotherapy, based on scaling of existing treatment plans up to normal tissue dose constraints, enables dose

  12. SU-E-T-776: Use of Quality Metrics for a New Hypo-Fractionated Pre-Surgical Mesothelioma Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, S; Mehta, V [Swedish Cancer Institute, Seattle, WA (United States)

    2015-06-15

    Purpose: The “SMART” (Surgery for Mesothelioma After Radiation Therapy) approach involves hypo-fractionated radiotherapy of the lung pleura to 25Gy over 5 days followed by surgical resection within 7. Early clinical results suggest that this approach is very promising, but also logistically challenging due to the multidisciplinary involvement. Due to the compressed schedule, high dose, and shortened planning time, the delivery of the planned doses were monitored for safety with quality metric software. Methods: Hypo-fractionated IMRT treatment plans were developed for all patients and exported to Quality Reports™ software. Plan quality metrics or PQMs™ were created to calculate an objective scoring function for each plan. This allows for an objective assessment of the quality of the plan and a benchmark for plan improvement for subsequent patients. The priorities of various components were incorporated based on similar hypo-fractionated protocols such as lung SBRT treatments. Results: Five patients have been treated at our institution using this approach. The plans were developed, QA performed, and ready within 5 days of simulation. Plan Quality metrics utilized in scoring included doses to OAR and target coverage. All patients tolerated treatment well and proceeded to surgery as scheduled. Reported toxicity included grade 1 nausea (n=1), grade 1 esophagitis (n=1), grade 2 fatigue (n=3). One patient had recurrent fluid accumulation following surgery. No patients experienced any pulmonary toxicity prior to surgery. Conclusion: An accelerated course of pre-operative high dose radiation for mesothelioma is an innovative and promising new protocol. Without historical data, one must proceed cautiously and monitor the data carefully. The development of quality metrics and scoring functions for these treatments allows us to benchmark our plans and monitor improvement. If subsequent toxicities occur, these will be easy to investigate and incorporate into the

  13. Automated patient setup and gating using cone beam computed tomography projections

    DEFF Research Database (Denmark)

    Wan, Hanlin; Bertholet, Jenny; Ge, Jiajia

    2016-01-01

    In radiation therapy, fiducial markers are often implanted near tumors and used for patient positioning and respiratory gating purposes. These markers are then used to manually align the patients by matching the markers in the cone beam computed tomography (CBCT) reconstruction to those...

  14. On photonic controlled phase gates

    International Nuclear Information System (INIS)

    Kieling, K; Eisert, J; O'Brien, J L

    2010-01-01

    As primitives for entanglement generation, controlled phase gates have a central role in quantum computing. Especially in ideas realizing instances of quantum computation in linear optical gate arrays, a closer look can be rewarding. In such architectures, all effective nonlinearities are induced by measurements. Hence the probability of success is a crucial parameter of such quantum gates. In this paper, we discuss this question for controlled phase gates that implement an arbitrary phase with one and two control qubits. Within the class of post-selected gates in dual-rail encoding with vacuum ancillas, we identify the optimal success probabilities. We construct networks that allow for implementation using current experimental capabilities in detail. The methods employed here appear specifically useful with the advent of integrated linear optical circuits, providing stable interferometers on monolithic structures.

  15. GATE: Improving the computational efficiency

    International Nuclear Information System (INIS)

    Staelens, S.; De Beenhouwer, J.; Kruecker, D.; Maigne, L.; Rannou, F.; Ferrer, L.; D'Asseler, Y.; Buvat, I.; Lemahieu, I.

    2006-01-01

    GATE is a software dedicated to Monte Carlo simulations in Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET). An important disadvantage of those simulations is the fundamental burden of computation time. This manuscript describes three different techniques in order to improve the efficiency of those simulations. Firstly, the implementation of variance reduction techniques (VRTs), more specifically the incorporation of geometrical importance sampling, is discussed. After this, the newly designed cluster version of the GATE software is described. The experiments have shown that GATE simulations scale very well on a cluster of homogeneous computers. Finally, an elaboration on the deployment of GATE on the Enabling Grids for E-Science in Europe (EGEE) grid will conclude the description of efficiency enhancement efforts. The three aforementioned methods improve the efficiency of GATE to a large extent and make realistic patient-specific overnight Monte Carlo simulations achievable

  16. The use of hypofractionated intensity-modulated irradiation in the treatment of glioblastoma multiforme: preliminary results of a prospective trial.

    Science.gov (United States)

    Sultanem, Khalil; Patrocinio, Horacio; Lambert, Christine; Corns, Robert; Leblanc, Richard; Parker, William; Shenouda, George; Souhami, Luis

    2004-01-01

    Despite major advances in treatment modalities, the prognosis of patients with glioblastoma multiforme (GBM) remains poor. Exploring hypofractionated regimens to replace the standard 6-week radiotherapy schedule is an attractive strategy as an attempt to prevent accelerated tumor cell repopulation. There is equally interest in dose escalation to the gross tumor volume where the majority of failures occur. We report our preliminary results using hypofractionated intensity-modulated accelerated radiotherapy regimen in the treatment of patients with GBM. Between July 1998 and December 2001, 25 patients with histologically proven diagnosis of GBM, Karnofsky performance status > or =60, and a postoperative tumor volume step-and-shoot technique), 60 Gy in 20 daily fractions of 3 Gy each were given to the GTV, whereas the planning target volume received a minimum of 40 Gy in 20 fractions of 2 Gy each at its periphery. Treatments were delivered over a 4-week period using 5 daily fractions per week. Dose was prescribed at the isocenter (ICRU point). Three beam angles were used in all of the cases. Treatments were well tolerated. Acute toxicity was limited to increased brain edema during radiotherapy in 2 patients who were on tapering doses of corticosteroids. This was corrected by increasing the steroid dose. At a median follow-up of 8.8 months, no late toxicity was observed. One patient experienced visual loss at 9 months after completion of treatment. MRI suggested nonspecific changes to the optic chiasm. On review of the treatment plan, the total dose to the optic chiasm was confirmed to be equal to or less than 40 Gy in 20 fractions. When Radiation Therapy Oncology Group recursive partitioning analysis was used, 10 patients were class III-IV, and 15 patients were class V-VI. To date, 21 patients have had clinical and/or radiologic evidence of disease progression, and 16 patients have died. The median survival was 9.5 months (range: 2.8-22.9 months), the 1-year survival

  17. The respiratory microbiome and respiratory infections

    NARCIS (Netherlands)

    Unger, Stefan A.; Bogaert, Debby

    2017-01-01

    Despite advances over the past