Maximum Inhalation Research Articles

SU‐E‐J‐115: A Study of Tumor Volume Parameters in Lung Cancer Patients and the Possible Effects on Tumor Motion

Purpose: To study volume parameters and how they might affect tumor motion in lung cancer patients. Methods: Nine patients with lung lesions were imaged with a Philips Brilliance Big Bore 4D CT scanner before and after receiving radiation therapy treatment. A single board certified radiation oncologist contoured all patient tumors in zero (maximum inhalation) and fifty percent (full exhalation) phases. Images were ported to the treatment planning system Pinnacle© 9.0. Volume measurements of the lesions were automatically obtained from these contours. Maximal tumor dimensions were obtained manually in the saggital, coronal, and transverse planes. Tumor motion was assessed from the centroid tumor locations (obtained automatically) between respiratory phases. Centroid distance to the diaphragm was also measured. Results: A comparison of the difference from the spherical equivalent volume (SV) based upon the maximal tumor dimension and the volume measurements from Pinnacle© were compared. A linear correlation (R̂2 = 0.972) was noted. A correlation using a power law fit was determined between tumor motion and distance from the diaphragm for the initial scan and subsequent rescan (R̂2 = 0.251 and R̂2 = 0.249 respectively). Tumor motion was separated based upon which planar view the maximal tumor dimension was found to be in. Tumors with the largest sagittal dimensions (5 scans) had an average and standard deviation in tumor motion of 0.47 +/− 0.61 cm, coronal (5 scans) had 1.29 +/− 0.43 cm, and transverse (8 scans) had 0.61 +/− 0.31 cm. Conclusions: The data suggests a correlation to estimate spherical equivalent volume (SV) and thus the maximal dimension of the lesion. Also, if this maximal dimension was found in the coronal view, those tumors exhibited approximately twice as much tumor motion between respiratory phases as compared with tumors with maximal dimensions found in the other planar views.

TH‐A‐220‐10: Ventilation Imaging of the Lung: Comparison of 4DCT with Hyperpolarized Helium‐3 MR

Purpose: Radiation induced pulmonary diseases can change the tissue material properties of lung parenchyma and the regional ventilation. 4DCT can be used to measure regional ventilation when combined with non‐linear 3D image registration. The purpose of this study is to analyze the effects of the B‐Spline grid spacing and the weighting of linear elasticity in 4DCT and image registration based measurement of ventilation by comparing the result to hyperpolarized helium‐3 MR (HP He‐3 MR). Methods: 4DCT data set and HP He‐3 MR before RT were acquired from one patient. The regularized tissue volume and vesselness preserving image registration algorithm was applied to register the maximum inhalation image to the maximum exhalation image for the measurement of regional ventilation. The HP He‐3 MR ventilation map was rigidly registered to the maximum exhalation image for direct comparison to the 4DCT derived ventilation map. Relative overlap (RO) was used to quantify the similarity between the two measurements. Ventilation maps derived from different B‐Spline grid spacing and Laplacian weighting in the image registration were compared. Results: The similarity between the two measurements increases as the increase of the B‐Spline grid spacing and Laplacian weighting which result a smoother ventilation map. In this study, the best similarity with the RO value 0.75 is found with Laplacian weighting of 0.5 and B‐Spline grid spacing of 32 mm. The Laplacian weighting of 0.01 with B‐Spline grid spacing of 8 mm shows the lowest OR value of 0.68. Visual inspection indicates the two measurements have similar anterior/posterior and superior/inferior gradients. Conclusions: We have compared the 4DCT based ventilation measurement with the results from hyperpolarized helium‐3 MR. This result will be valuable for improving the lung CT image registration algorithm toward accuracy not only in the measure of landmark error but also the underlying physiological changes.This work is is supported in part by NIH 1R21CA144063.

SU‐E‐J‐48: Measurement of Radiation Induced Pulmonary Function Change from 4DCT

Purpose: 4DCT can be used to measure pulmonary function change following radiation therapy for adaptive treatment planning. The purpose of this study is to analyze the effects of the measurement variation and compare the planned radiation dose and pulmonary function change due to radiation not measurement variation. Methods: Two 4DCT data sets before RT scanned with thirty minutes break and one 4DCT data set acquired 5 months after RT from one patient were used in this study. Tissue volume and vesselness preserving image registration algorithm was applied to register the maximum inhalation image to the maximum exhalation image for the calculation of local lung expansion as a measurement of regional pulmonary function (PF). The pulmonary function changes (PFC) before RT and after RT were calculated via the PF ratio between two 4DCT scans. The radiation induced pulmonary function change (RI‐PFC) is calculated from PFC after RT by filtering measurement variation calculated in PFC before RT. We compared the RI‐PFC with planned radiation dose at the contralteral/ipsilateral lung, and the upper/lower lobes of the ipsilateral lung. Results: Significant measurement difference is found between lobes in the same ipsilateral lung. For the contralateral lung in the RI‐PFC region, the average radiation dose is 2.5 Gy and the average PFC value is 1.10. For the ipsilateral lung in the RI‐PFC region, left upper lobe shows the average ration dose as 59.1 Gy with average PFC value 0.9, and the left lower lobe shows the average ration dose as with 2.5 Gy the average PFC value 1.14. Conclusions: We described a technique that uses 4DCT, image registration and biomechanical analysis to measure regional pulmonary function change. We compared the radiation induced pulmonary function change to the planned radiation dose distribution and examined the differences in different lungs, and at the lobar level.This work was supported in part by NIH grant HL079406 and EB004126.

SU‐E‐T‐287: The Clinical Evaluation of a Novel Amplitude‐Based Binning Algorithm for 4D CT Reconstruction

Purpose: To evaluate the performance of the first commercial amplitude‐binning algorithm for 4DCT reconstruction, to compare its reconstructed image quality to that of the phase‐binning algorithm, and to investigate possible clinical effects from changing algorithms. Methods: A department customized 4DCT motion phantom was utilized to evaluate the geometry accuracy (correct phase sequencing and motion) of the amplitude‐binning algorithm. 64 4DCT patient cases, in which 60(4) cases were acquired with 4D chest (abdomen) protocol, were collected and evaluated on the respiratory motion artifact severity. The MIP images generated from both algorithms for 10 SBRT cases were further evaluated by two radiation oncologists regarding the tumor sizes and locations. Results: The phantom experiments illustrated that, as expected, maximum inhalation occurred between 90%–10% phases, while maximum exhalation occurred between 40%–60% phases. The amplitude‐binning algorithm provides reasonable phase sequencing and motion within the 4D images. The amplitude‐binning algorithm yielded fewer respiratory motion artifacts on 24/64 cases (37.5%), comparable artifacts to the phase‐binning algorithm on 35/64 cases (54.7%), and slightly greater artifacts on 5/64 cases (7.8%). The 10 SBRT cases indicated that the reconstructed tumor sizes and locations were comparable on 9 MIP image pairs generated from amplitude‐binning and phase‐binning, respectively. However, amplitude‐binning yielded smaller tumor size on one case probably due to the very shallow respiratory amplitude occurring over several breathing cycles. Conclusions: Overall, amplitude‐binning algorithm yielded fewer or equivalent artifacts on 92.2% of cases (59/64 cases), and no dramatic difference on reconstructed tumor sizes and locations from the MIP images based on amplitude and phase binning algorithms. We suggest utilizing the amplitude‐binning 4DCT images for clinical practice, especially for SBRT cases. If very shallow respiratory waves or severe motion artifacts were found on specific cases, physicists should work with the physicians to provide the best achievable 4D images.

WE‐E‐BRC‐07: Evaluate Reproducibility of 4DCT Registration‐Based Lung Ventilation Measurement with Gamma Comparison Method

Purpose: The regional lung pulmonary function can be calculated by computing the Jacobian of image registration deformation field. Radiation‐induced pulmonary function changes are assessed by comparing pulmonary function before and after radiation therapy (RT). Due to the probably different breath pattern and effort, uncertainties from 4DCT imaging and registration error, we need to first establish the measurement reproducibility. We also introduce gamma comparison method to compensate space disalignment in two distributions. Methods: Two repeated 4DCT data sets scanned with 30 minutes interval before RT from two patients are used in this study. Tissue volume preserving nonrigid registration algorithm with Laplacian regularization constraints was applied to register the maximum exhalation image to the maximum inhalation image for the calculation of local lung expansion as a measurement of regional pulmonary function in two scans. We compared the two pulmonary functions and analyzed the pulmonary function ratio map. Gamma comparison method is introduced to tolerate possible error in image acquisition and image registration. Mean and standard deviation of pulmonary function ratio map and gamma pass percent are calculated to measure reproducibility. Results: The registration accuracy analysis indicated our registration error is on the order of 1.0 mm. Most lung tissue has a reproducible pulmonary function. Reproducibility near the diaphragm is worse than other regions. The standard deviation of function ratio map is respectively 0.0352 and 0.0495. The gamma comparison pass percent is respectively 84% and 87%. Further plots suggest most of the lung function is reproducible in 2 scans. Conclusions: We analyzed the reproducibility to measure regional pulmonary function using 4DCT and image registration. We compared the regional lung function in two repeated 4DCT scan and discussed the function ratio map. We also introduced a gamma comparison method to quantify reproducibility.This work was supported in part by NIH grant HL079406 and EB004126.

Comparison of Radiotherapy Treatment Plans for Left-sided Breast Cancer Patients based on Three- and Four-dimensional Computed Tomography Imaging

Aims The target volume for breast radiotherapy after conservative surgery for breast cancer may be affected by breathing motion. We investigated differences between conventional and four-dimensional computed tomography-based treatment planning and whether gating could improve dose volume parameters. Materials and methods Ten patients with left-sided breast cancer and surgical clips at the excision site had conventional treatment planning computed tomography and four-dimensional computed tomography. Treatment plans using two tangential beams (6 MV X-rays) were optimised for target coverage and homogeneity using a field in field technique for the three-dimensional scan. This plan was applied directly to four-dimensional datasets representing individual phases of the breathing cycle and combinations thereof (average and maximum intensity projection). Optimised plans were generated for the maximum inhalation scan to study what could potentially be achieved in gated radiotherapy. Results Four-dimensional computed tomography with effective doses of around 10 mSv proved to be adequate for treatment planning in all patients. The average motion of the surgical clips was 3.7 mm (range 1.7–6.5 mm), which was similar to the movement of the chest wall. With a margin of 7 mm for the whole breast to planning target volume, conventional three-dimensional computed tomography-based planning was found to adequately cover the target as seen on four-dimensional computed tomography without significant differences in normal tissue sparing. Improved sparing of the heart and lung could only be achieved by reducing the posterior margin of the target volume, which may be justified if four-dimensional computed tomography is used to determine the target and its motion. Conclusion No significant benefit has been shown for the use of four-dimensional computed tomography-based planning if motion management is not implemented concurrently with a reduced posterior margin between clinical and planning target volumes.

Estimation of three‐dimensional intrinsic dosimetric uncertainties resulting from using deformable image registration for dose mapping

This article presents a general procedural framework to assess the point-by-point precision in mapped dose associated with the intrinsic uncertainty of a deformable image registration (DIR) for any arbitrary patient. Dose uncertainty is obtained via a three-step process. In the first step, for each voxel in an imaging pair, a cluster of points is obtained by an iterative DIR procedure. In the second step, the dispersion of the points due to the imprecision of the DIR method is used to compute the spatial uncertainty. Two different ways to quantify the spatial uncertainty are presented in this work. Method A consists of a one-dimensional analysis of the modules of the position vectors, whereas method B performs a more detailed 3D analysis of the coordinates of the points. In the third step, the resulting spatial uncertainty estimates are used in combination with the mapped dose distribution to compute the point-by-point dose standard deviation. The process is demonstrated to estimate the dose uncertainty induced by mapping a 62.6 Gy dose delivered on maximum exhale to maximum inhale of a ten-phase four-dimensional lung CT. For the demonstration lung image pair, the standard deviation of inconsistency vectors is found to be up to 9.2 mm with a mean sigma of 1.3 mm. This uncertainty results in a maximum estimated dose uncertainty of 29.65 Gy if method A is used and 21.81 Gy for method B. The calculated volume with dose uncertainty above 10.00 Gy is 602 cm3 for method A and 1422 cm3 for method B. This procedure represents a useful tool to evaluate the precision of a mapped dose distribution due to the intrinsic DIR uncertainty in a patient. The procedure is flexible, allowing incorporation of alternative intrinsic error models.

Single-breath counting: a pilot study of a novel technique for measuring pulmonary function in children

Introduction Although peak expiratory flow rate is the conventional way to measure asthma severity in adults, its use is problematic in children because it is effort dependent. Forced expiratory volume in 1 second (FEV 1) and the ratio of FEV 1 to forced vital capacity (FEV 1/FVC) are more accurate, but generally not available in the emergency department (ED). A better test is needed. Single-breath counting (SBC) is the measurement of how far an individual can count in a normal speaking voice after a maximal effort inhalation. The count is in cadence to a metronome set at 2 beats per second. Previous work has suggested that SBC correlates with standard measures of pulmonary function in adults. However, it has never been tested in children. Objectives The aims of this study are to determine if SBC can be easily performed by children and to assess the correlation between SBC and standard measures of pulmonary function in a pediatric population. Methods This was a prospective observational study of a convenience sample of children presenting to the pulmonary clinic for scheduled pulmonary function testing (PFT). Peak expiratory flow rate, FEV 1, FVC, forced expiratory flow 25% to 75%, and FEV 1/FVC were measured and recorded. After PFT, subjects were asked to perform SBC. Three attempts were allowed, and the average was recorded. Correlation was determined by the Pearson coefficient. Results Sixty-seven children (ages 5-18 years, 64% male) were enrolled. All were able to understand and complete the testing. Indications for PFT included asthma and/or allergies (n = 44), cystic fibrosis (n = 9), and other chronic diseases (n = 14). The correlations ( r) of SBC to peak expiratory flow rate, FEV 1, FVC, forced expiratory flow 25% to 75%, and FEV 1/FVC were 0.55, 0.66, 0.71, 0.44, and −0.29, respectively ( P < .05 for all results). Conclusion Single-breath counting is easy to perform in children, seems to correlate well with standard measures of pulmonary function, and shows promise for measuring asthma severity in children. Further work to define the range of reference SBC values (as a function of age and/or body size) and an evaluation of the utility of SBC in an ED population of acute asthmatics is indicated.

Four-dimensional deformable image registration using trajectory modeling

A four-dimensional deformable image registration (4D DIR) algorithm, referred to as 4D local trajectory modeling (4DLTM), is presented and applied to thoracic 4D computed tomography (4DCT) image sets. The theoretical framework on which this algorithm is built exploits the incremental continuity present in 4DCT component images to calculate a dense set of parameterized voxel trajectories through space as functions of time. The spatial accuracy of the 4DLTM algorithm is compared with an alternative registration approach in which component phase to phase (CPP) DIR is utilized to determine the full displacement between maximum inhale and exhale images. A publically available DIR reference database (http://www.dir-lab.com) is utilized for the spatial accuracy assessment. The database consists of ten 4DCT image sets and corresponding manually identified landmark points between the maximum phases. A subset of points are propagated through the expiratory 4DCT component images. Cubic polynomials were found to provide sufficient flexibility and spatial accuracy for describing the point trajectories through the expiratory phases. The resulting average spatial error between the maximum phases was 1.25 mm for the 4DLTM and 1.44 mm for the CPP. The 4DLTM method captures the long-range motion between 4DCT extremes with high spatial accuracy.

Sci-Thurs PM: Planning-05: Comparison of 4DCT Contouring on Exhalation + Inhalation Phases and Maximum Intensity Projection (MIP) for Lung Cancer

4DCT has been widely used in radiation therapy planning to determine target motion and generate the internal target volume (ITV). However, contouring on all respiratory phases created by 4DCT may not be the most efficient way to generate ITV. To develop a practical contouring protocol of adequate accuracy, we compared in this study two available approaches: one is to combine the target contours from the maximum exhalation and inhalation phases only; the other is to contour on the derived Maximum Intensity Projection (MIP). In this study, our physicians contoured the target for 11 lung‐cases (Stage Ia to IIIb), all scanned using 4DCT on a Philips 16‐slice big bore. For the 2 of the 11 cases without the target abutting other structures, the combined contour from the exhale and inhale phases (ITV_ex+in) was entirely encompassed by the contour from MIP (ITV_MIP). However, 28% (6.3cc) of ITV_MIP was outside ITV_ex+in in one case. This underestimation of the target volume by ITV_ex+in might be partially due to the curved trajectory of the target motion. In the rest 9 cases, all with the target abutting other structures, 5 cases had 2.5∼6.8cc ( median =4.4 cc ) of ITV_ex+in outside ITV_MIP. The underestimation of the target volume by ITV_MIP was due to portions of the target in one respiratory phase being shadowed in MIP by abutting structures from another phase. Our results indicate that for determining ITV in lung on 4DCT it is necessary to combine contours from all three sets including MIP, exhale and inhale phases.

SU‐FF‐J‐171: Quantification of Ventilation Imaging From Clinical 4DCT Datasets for Selective Avoidance IMRT in Non‐Small Cell Lung Cancer

Purpose: To determine a clinically appropriate ventilation level for selective avoidance IMRT using clinical 4D CT data sets and a small‐deformation inverse‐consistent linear‐elastic (SICLE) registration algorithm Materials/Methods: Using SICLE, the maximum inhalation and expiration phases of 4D CT datasets from 6 NSCLC patients were registered. After registration, smoothing was applied to the input images to account for registration error. A correction was applied to the voxels in the inhalation image to account for lung tissue mass discrepancy due to lung inflation. The ventilation was calculated voxel by voxel as a local volume change, DV/Vex = 1000 (HUin − HUex)/(HUex(1000 + HUin)), where HUex and HUin are the Hounsfield units associated with the expiration and inhalation images, respectively. After this, an additional smoothing filter and a cumulative distribution function were applied to aid segmentation and normalize the data between 0% and 100%. Ventilation volumes were quantified as a function of normalized ventilation level, which can be used as a threshold for delineation of ventilation subregions. Results: Using the inhalation image registered to the expiration image, consistent ventilation images were calculated. The ventilation levels of 90%, 80%, 70%, 60%, and 50% were studied as it was determined that ventilation levels below 50% would not be beneficial as this region would include almost the entirety of the lungs. An exponential relationship between ventilation level and ventilationcompetent volume at a given percentage ventilation was observed. Quantified ventilation data and charts demonstrating these relationships were generated. Conclusions: In selective avoidance IMRT for NSCLC, it is critical to determine the optimal ventilation level to segment within a normal lung region, which would then be used as an avoidance structure in functional image guided IMRT. Our study shows that a 70% ventilation level is promising to be implemented into selective avoidance IMRT techniques for NSCLC.

SU‐GG‐BRC‐07: 4DCT‐Based Measurement of Radiation Induced Changes in Pulmonary Function

Purpose The present treatment‐planning dosimetry constraints for the lung are based on studies that assume lung tissue is homogeneous in its response to toxicity, irrespective of tissue location or underlying function. No human studies have investigated the relationships between local lung function, spatial radiation dose distribution, and radiation induced lung function changes. We are able to observe radiation‐induced changes in lung tissue function using 4DCT and image registration. Method and Materials Two 4DCT data sets before and after RT from one patient are used in this study. Nonlinear, 3D image registration was applied to register the maximum exhalation image to the maximum inhalation image for the calculation of local lung expansion as a measurement of regional pulmonary function. We compared the changes of pulmonary function before and after RT with planned radiation dose at different locations of the lung. Results The registration accuracy analysis indicated our registration error is on the order of 1 mm. The pulmonary function change in left lung where the tumor is located is larger than it is in right lung (maximum Jacobian change is respectively 0.23 and 0.15). The highest correlation of the pulmonary function change to the delivered radiation dose is in regions which are at the distance of 20 to 25 mm to the tumor region (linear regression, r = −0.73). Further plots between the radiation dose and the pulmonary function change suggest the lung tissue function change is not sole based on radiation dose. Conclusion We described a technique that uses 4DCT, image registration and biomechanical analysis to measure regional lung function. We compared the regional lung function before and after RT to the planned radiation dose distribution and examined the differences at the treatment location and in non‐treatment regions.Conflict of Interest VIDA Diagnostics, Inc (shareholder).

PAHs: Choi et al. Respond

PAHs: Choi et al. Respond

Multipathway Screening Factors for Assessing Risks from Ingestion Exposures to Air Pollutants

Regulatory agencies are frequently called upon to assess the potential for significant environmental impacts from air pollution emissions. These assessments often entail air dispersion modeling to estimate air concentrations that can be compared with standards or health benchmarks. Some air pollutants can also impact human health through pathways in media besides air. Risk assessment models are available that consider pollutant deposition, movement, uptake, and other processes on land and water and in biota, but they are typically effort-intensive. A screening-level assessment of potential multipathway effects would be useful. We developed multipathway screening factors (MPSFs) that can be applied to inhalation risk estimates to give screening estimates of risks via ingestion pathways. The MPSFs were generated using a generic multipathway risk assessment, consisting of air dispersion and deposition modeling followed by risk modeling for 42 persistent, bioaccumulative air pollutants. MPSFs are defined as the ratio of ingestion risks to inhalation risks. We report here the results of a sensitivity analysis that evaluates the effects on the MPSF ratio of varying inputs to the air dispersion and deposition modeling analysis. Model input parameters were systematically varied and multipathway risks recalculated. From the sensitivity analysis results, reasonable upper-bound values for the ratio of ingestion risks to inhalation risks for each pollutant were selected. The particle size distribution and the method of calculating particle deposition had the most disproportionate effect on inhalation versus ingestion risks and the greatest effect on MPSFs. Risk calculations are often done at the points of maximum air concentration and maximum deposition. In this study, the MPSFs were usually highest at the location of the maximum inhalation risk.

Three-Dimensional Numerical Simulation of Nanoparticle Inhalation and Indoor Pollution around Breathing Human

There is increasing concern about the health effects of particulate pollutants such as the SARS virus, influenza and diesel emission particles; moreover, restrictions on them are becoming stringent. In this study, particle motions and flows around a human with periodic breathing are numerically solved to predict the gas-particulate two-phase flows. Since the targeted particles are bacteria and viruses, the particle sizes are selected as 1 μm and 100 nm in diameter with a density of 10 kg/m3, respectively. Three-dimensional numerical simulation was employed using the Lagrange approach for particle motion and the standard k-e model for flows. In the human breathing cycle, inhalation flow exists in the vicinity of the human face within a small area. Exhalation flows exists below the inhalation flow and is spread across a larger area. Downward streams coming from the upper region to the region near the nose are observed not only at the maximum inhalation time but also at the maximum exhalation time. With these downward streams, particles always move downward when inhalation occurs. Motions of particles away from the human body with right-left unsymmetrical vortexes are observed. Particles reach the human nose when the source distance is less than 30 cm. A maximum of 9.9 % of the nanoparticles are captured. When the source distance L is 10 cm, smaller particles of d = 100 nm tend to have high captured efficiency. On the other hand, more 1 μm particles are captured when the source distance is 20 cm or greater.

Hamo-study i: investigation of the effect of breathing on the position of the heart

Introduction: One of the most important notions in osteopathy is that our body structures possess a certain freedom of motion, which is necessary to function properly. We also know that respiration influences the motion of the heart. This study proposes a method to quantify this motion of the heart. Design: Observational study Methods: A Gyroscan T10-NT (magnetic resonance) has been used. In order to obtain a good three-dimensional image, localizer images were made in the three orthogonal planes (axial, sagittal and frontal). After this images were made in the long axis (two-chamber view), short axis and four-chamber view. Images were made in expiration, inspiration and in neutral position using ECG-triggering. The research group for this study consisted of 10 healthy subjects (5 men, 5 woman). A total of 5021 images were made and all results were analysed with the Friedman test, with significant results if p p<0.1. Results: The position of the apex cordis showed a significant (p<0.01) movement in the three orthogonal planes. The apex moved caudally (20.3mm, SD. 8.59mm). anteriorly (17.1mm, SD. 4.70mm) an to the right (13.9mm, SD. 8.46mm) during inhalation (meaning the difference between maximal exhalation and maximal inhalation). The axis changes measured on the long axis did not achieve statistical significance. Although, at sight, a clear verticalization was observed in all subjects, measurements only showed a tendency (p¼0.067) to verticalization during inhalation. No axis changes have been observed in the short axis. Conclusions: Despite the small group of subjects, this study clearly shows a change in position of the heart under influence of breathing. The apex moves caudal, anterior and to the right. The heart tends to verticalize and so to say stand on his apex. During expiration the opposite movement has been found.

Spinal and sacroiliac joint assessment and treatment within the American osteopathic profession

Introduction: One of the most important notions in osteopathy is that our body structures possess a certain freedom of motion, which is necessary to function properly. We also know that respiration influences the motion of the heart. This study proposes a method to quantify this motion of the heart. Design: Observational study Methods: A Gyroscan T10-NT (magnetic resonance) has been used. In order to obtain a good three-dimensional image, localizer images were made in the three orthogonal planes (axial, sagittal and frontal). After this images were made in the long axis (two-chamber view), short axis and four-chamber view. Images were made in expiration, inspiration and in neutral position using ECG-triggering. The research group for this study consisted of 10 healthy subjects (5 men, 5 woman). A total of 5021 images were made and all results were analysed with the Friedman test, with significant results if p p<0.1. Results: The position of the apex cordis showed a significant (p<0.01) movement in the three orthogonal planes. The apex moved caudally (20.3mm, SD. 8.59mm). anteriorly (17.1mm, SD. 4.70mm) an to the right (13.9mm, SD. 8.46mm) during inhalation (meaning the difference between maximal exhalation and maximal inhalation). The axis changes measured on the long axis did not achieve statistical significance. Although, at sight, a clear verticalization was observed in all subjects, measurements only showed a tendency (p1⁄40.067) to verticalization during inhalation. No axis changes have been observed in the short axis. Conclusions: Despite the small group of subjects, this study clearly shows a change in position of the heart under influence of breathing. The apex moves caudal, anterior and to the right. The heart tends to verticalize and so to say stand on his apex. During expiration the opposite movement has been found.

Titanium clip placement to allow accurate tumour bed localisation following breast conserving surgery – audit on behalf of the IMPORT Trial Management Group

To assess the feasibility of radiation therapy treatment planning 4-dimensional computed tomography (4DCT) and deep-inspiration breath-hold (DIBH) CT to accurately contour the left anterior descending artery (LAD), a primary indicator of radiation-induced cardiac toxicity for patients undergoing radiation therapy.Ten subjects were prospectively imaged with a cardiac-gated MRI protocol to determine cardiac motion effects, including the displacement of a region of interest comprising the LAD. A series of planar views were obtained and resampled to create a 3-dimensional (3D) volume. A 3D optical flow deformable image registration algorithm determined tissue displacement during the cardiac cycle. The measured motion was then used as a spatial boundary to characterize motion blurring of the radiologist-delineated LAD structure for a cohort of 10 consecutive patients enrolled prospectively on a breast study including 4DCT and DIBH scans. Coronary motion–induced blurring artifacts were quantified by applying an unsharp filter to accentuate the LAD structure despite the presence of motion blurring. The 4DCT maximum inhalation and exhalation respiratory phases were coregistered to determine the LAD displacement during tidal respiration, as visualized in 4DCT.The average 90th percentile heart motion for the region of interest was 0.7 ± 0.1 mm (left–right [LR]), 1.3 ± 0.6 mm (superior–inferior [SI]), and 0.6 ± 0.2 mm (anterior–posterior [AP]) in the cardiac-gated MRI cohort. The average relative increase in the number of voxels comprising the LAD contour was 69.4% ± 4.5% for the DIBH. The LAD volume overestimation had the dosimetric impact of decreasing the reported mean LAD dose by 23% ± 9% on average in the DIBH. During tidal respiration the average relative LAD contour increase was 69.3% ± 5.9% and 67.9% ± 4.6% for inhalation and exhalation respiratory phases, respectively. The average 90th percentile LAD motion was 4.8 ± 1.1 mm (LR), 0.9 ± 0.4 mm (SI), and 1.9 ± 0.6 mm (AP) for the 4DCT cohort, in the absence of cardiac gating.An anisotropic margin of 2.7 mm (LR), 4.1 mm (SI), and 2.4 mm (AP) was quantitatively determined to account for motion blurring and patient setup error while placing minimum constraint on the plan optimization.

Thermoplastic Patient Fixation

Several methods have been developed to reduce tumor motions and patient movements during radiotherapy of lung cancer. In this study, a multislice CT-based analysis was performed to examine the effect of a thermoplastic patient immobilization system on the chest wall and tumor motions. Ten patients with stage II–IV lung cancer were enrolled into the study. According to tumor localization, five patients had peripheral, and five patients central lung cancer (T2–T4). In total, six series of measurements were made with a multislice CT scanner, both with and without mask fixation, in normal breathing, at maximal tidal volume inhalation, and at maximal tidal volume exhalation. Movements of chest wall, diaphragm and tumor, with and without mask, under different breathing conditions were registered. With the use of the immobilization system, no significant difference was found in diaphragmatic movements (mean deviation of diaphragm: 41.7–40.5 mm to the right, and 40.5–36.8 mm to the left side) and in tumor motions (mean deviation of tumor: 15.3–12.4 mm in craniocaudal, and 11.5–8.8 mm in posterolateral direction, mean medial deviation: 4.6–4.1 mm, mean lateral deviation: 7.2–5 mm). Significant differences were observed concerning tumor motions in anteroposterior direction (mean: 8.9–6.3 mm) and transverse chest movements in anteroposterior direction. Besides the advantage of optimal patient positioning, the movements of the bony chest wall can be considerably reduced by using the immobilization system. However, this fixation system has limitations concerning its suitability for minimizing tumor motions.

Spacer inhalation technique and deposition of extrafine aerosol in asthmatic children

The aim of the present study was to measure airway, oropharyngeal and gastrointestinal deposition of (99m)Tc-labelled hydrofluoroalkane-beclomethasone dipropionate after inhalation via a pressurised metered-dose inhaler and spacer (Aerochamber Plus) in asthmatic children. A group of 24 children (aged 5-17 yrs) with mild asthma inhaled the labelled drug. A total of 12 children took five tidal breaths after each actuation (tidal group). The other 12 children used a slow maximal inhalation followed by a 5 - 10-s breath-hold (breath-hold group). Simultaneous anterior and posterior planar gamma-scintigraphic scans (120-s acquisition) were recorded. For the tidal group, mean+/-sd lung deposition (% ex-actuator, attenuation corrected) was 35.4+/-18.3, 47.5+/-13.0 and 54.9+/-11.2 in patients aged 5-7 (n = 4), 8-10 (n = 4) and 11-17 yrs (n = 4), respectively. Oropharyngeal and gastrointestinal deposition was 24.0+/-10.5, 10.3+/-4.4 and 10.1+/-6.2. With the breath-hold technique, lung deposition was 58.1+/-6.7, 56.6+/-5.2 and 58.4+/-9.2. Oropharyngeal and gastrointestinal deposition was 12.9+/-3.2, 20.1+/-9.5 and 20.8+/-8.8. Inhalation of the extrafine formulation with the breath-hold technique showed significantly improved lung deposition compared with tidal breathing across all ages. Oropharyngeal and gastrointestinal deposition was markedly decreased, regardless of which inhalation technique was applied, compared with a previous paediatric study using the same formulation delivered via a breath-actuated metered-dose inhaler.