| 1. |
- Chen, Y., et al.
(author)
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Brain injury prediction for vulnerable road users in vehicle accidents using mathematical models
- 2010
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In: International Federation for Medical and Biological Engineering Proceedings. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1680-0737. - 9783540790389 ; 31, s. 497-500
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Conference paper (peer-reviewed)abstract
- The objective was to analyze the brain tissue responses and predict head-brain injuries. Accident reconstructions were carried out by using MBS and FE models based on real-life accident investigation. Thirty cases of VRUs accidents were selected from IVAC and GIDAS databases for simulation study. The brain injury parameters were calculated in terms of coup/countercoup pressure, von Mises and maximum shear stresses at the cerebrum, the callosum, the cerebellum and the brain stem. The correlation of calculated parameters was determined with injury codes observed in accident data. The results indicated that peak coup/countercoup pressures often occur at the cerebrum, while von Mises and maximum shear stresses are both concentrated at the upper end of the brain stem. Physical parameters employed in this study are capable of predicting brain injuries. © 2010 International Federation for Medical and Biological Engineering.
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| 2. |
- Li, F., et al.
(author)
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A study on biofidelity of EEVC adult headform impactor using human head fe model and real world injury data
- 2010
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In: International Federation for Medical and Biological Engineering Proceedings. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1680-0737. - 9783540790389 ; 31, s. 509-512
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Conference paper (peer-reviewed)abstract
- The present paper investigates the biofidelity of EEVC adult headform impactor using human head FE model and real world injury data. Eight real world car-pedestrian accident reconstructions were conducted for assessment of biofidelity of the EEVC headform impactor. The outputs including head linear acceleration and HIC value were compared between EEVC headform impactor and human head model simulations. The results showed that the EEVC adult headform impactor has an acceptable biofidelity for evaluation of vehicle safety performance. The human head model and in-depth accident investigation are valuable approaches for evaluation of the biofidelity of the headform impactor. The results from the present study could be used as background knowledge for improving the biofidelity of EEVC adult headform impactor. © 2010 International Federation for Medical and Biological Engineering.
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| 3. |
- Wang, F., et al.
(author)
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FE modeling of the human neck responses in low-speed car collisions
- 2010
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In: International Federation for Medical and Biological Engineering Proceedings. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1680-0737. - 9783540790389 ; 31, s. 513-516
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Conference paper (peer-reviewed)abstract
- The main goal of the current study is to improve an FE neck model with human like response in vehicle frontal, rear-end and side collisions based on an existing model developed in Hunan University. This model consists of the cervical vertebrae, intervertebral discs, ligaments and muscles that are modeled with various element types. The neck model is validated against kinematics data from volunteer tests. The response of the model generally shows a good agreement with the test results for the main part of the time history of the collision events. Sensitivity analysis of the model shows that the Young's modulus of the disc has a great influence on the head-neck kinematics. © 2010 International Federation for Medical and Biological Engineering.
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| 4. |
- Albinsson, John, et al.
(author)
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Tracking Performance of Several Combinations of Common Evaluation Metrics and Sub-pixel Methods
- 2015
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In: 16th Nordic-Baltic Conference on Biomedical Engineering. - Cham : Springer International Publishing. - 1680-0737. ; 48, s. 13-16, s. 13-16
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Conference paper (peer-reviewed)abstract
- Motion estimation in a series of consecutive images is used in a variety of areas, e.g. video compression and investigation of tissue characteristics and organ function in medical images. Several methods exist both for estimating motions on a pixel level, e.g. block-matching in which two blocks in consecutive images are compared by an evaluation metric, and on a sub-pixel level. In this paper, we have evaluated the tracking performance of all combinations between three evaluation metrics and eight sub-pixel estimation methods. The tracking performance of a sub-pixel method varies depending on the evaluation metric used. This indicates that a reported tracking performance for a sub-pixel estimation method can be significantly different when combined with another evaluation metric. Also there is a large variation in the time needed for the motion estimations depending primarily on the sub-pixel method used but also on the evaluation metric.
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| 5. |
- Arvidsson, Jonathan, 1986, et al.
(author)
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Automated estimation of in-plane nodule shape in chest tomosynthesis images
- 2015
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In: International Federation for Medical and Biological Engineering Proceedings. - Cham : Springer International Publishing. - 1680-0737. - 9783319129679 ; 48, s. 20-23
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Conference paper (peer-reviewed)abstract
- The purpose of this study was to develop an automated segmentation method for lung nodules in chest tomo-synthesis images. A number of simulated nodules of different sizes and shapes were created and inserted in two different locations into clinical chest tomosynthesis projections. The tomosynthesis volumes were then reconstructed using standard cone beam filtered back projection, with 1 mm slice interval. For the in-plane segmentation, the central plane of each nodule was selected. The segmentation method was formulated as an optimization problem where the nodule boundary corresponds to the minimum of the cost function, which is found by dynamic programming. The cost function was composed of terms related to pixel intensities, edge strength, edge direction and a smoothness constraint. The segmentation results were evaluated using an overlap measure (Dice index) of nodule regions and a distance measure (Hausdorff distance) between true and segmented nodule. On clinical images, the nodule segmentation method achieved a mean Dice index of 0.96 ± 0.01, and a mean Hausdorff distance of 0.5 ± 0.2 mm for isolated nodules and for nodules close to other lung structures a mean Dice index of 0.95 ± 0.02 and a mean Hausdorff distance of 0.5 ± 0.2 mm. The method achieved an acceptable accuracy and may be useful for area estimation of lung nodules.
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| 6. |
- Ask, Per, et al.
(author)
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Certification of Clinical Engineers in Sweden
- 2009
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In: WORLD CONGRESS ON MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING, VOL 25, PT 12. - Berlin, Heidelberg : Springer Science Business Media. - 1680-0737. ; 25:12, s. 430-431
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Journal article (peer-reviewed)abstract
- The Swedish Society for Biomedical Engineering and Physics have certified clinical engineers since 1994. The certification is done on tow levels: Master of science and Bachelor of science. We have in total had 614 applications and certified 341 engineers We have certified a total of 341 persons of which 75 are at the master level and 266 at the bachelor level. We are pleased to note that through the years so many engineers have applied and have get a certification. The interest for applying was very large in the beginning but decreased after some years.
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| 7. |
- Blad, Börje
(author)
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An electrical impedance model for deep brain stimulation of Parkinson's disease
- 2007
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In: 13th International Conference on Electrical Bioimpedance and the 8th Conference on Electrical Impedance Tomography. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1680-0737. - 9783540738404 ; 17, s. 60-61
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Conference paper (peer-reviewed)abstract
- Deep brain stimulation is an accepted technique for the treatment of Parkinson's disease. Deep brain stimulation affects the electrical functions of neurons and several explanations are available to describe this treatment modality. Such as depolarization blockade, synaptic inhibition, synaptic depression and stimulation induced modulation of pathological network activity. An electrical impedance model of the treatment area around the electrodes in the brain is determined to further increase the understanding of deep brain stimulation. This model shows the contact impedance between the electrodes and the tissue, the extra cellular resistance, the intra cellular resistance of the neurons and the effect of deep brain stimulation on the treated area in the brain, which in this case is stimulation of the sub thalamic nucleus. The generated electrical field near the electrodes is high enough to perform an electropermeabilization of the cell membranes. This is modelled as a cell membrane capacitance in series with a resistance. The resistance is the consequence of electropermeabilization of the cell membranes. Many observed parameters that occur during deep brain stimulation is reduced tremor activity, influence on speech, the same effect as a lesion, increased axon activity downstream, followed by durations of nerve silence.
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| 8. |
- Blad, Börje, et al.
(author)
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Beam Adjustments for Unflattened X-ray Beam Modes for an Elekta Synergy Linear Accelerator
- 2012
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In: IFMBE Proceedings. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1680-0737. - 9783642235085 ; 37, s. 683-685
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Conference paper (peer-reviewed)abstract
- A flattening filter free x-ray beam mode was added to an Elekta linear accelerator by placing a flat copper plate in the filter carousel and recalibrating the electron steering servo, gun servo and dosimetry system. Machine configurations were saved onto a separate hard disk in order to remain separate from the clinical configuration. Profile measurements with a Schuster BMS diode array show that the beam is stable and start up performance is similar to the normal filtered beam.
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| 9. |
- Dasu, Alexandru, et al.
(author)
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Dose painting by numbers - do the practical limitations of the technique decrease or increase the probability of controlling tumours?
- 2013
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In: IFMBE Proceedings. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 1680-0737 .- 1433-9277. ; 39, s. 1731-1734, s. 1731-1734
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Journal article (peer-reviewed)abstract
- One of the important questions regarding the feasibility of dose-painting-by-numbers approaches for treatment planning concerns the influence of the averaging of the imaging techniques used and the resolution of the planned and achieved dose distributions. This study investigates the impact of these aspects on the probability of controlling dynamic tumours. The effectiveness of dose painting approaches to target tumour hypoxia has been investigated in terms of the predicted tumour control probabilities (TCP) for tumours with dynamic oxygenations. Several levels of resolution for the resistance of the tumour or the planned dose distributions have been investigated. A very fine heterogeneous dose distribution ideally calculated at voxel level for a high target TCP would fail to control a tumour with dynamic oxygenation during the course of fractionated radiotherapy as mismatches between hotspots in the dose distribution and resistant hypoxic foci would lead to a significant loss in TCP. Only adaptive treatment would lead to reasonably high TCP. A coarse resolution for imaging or for dose distributions might compensate microscale mismatches in dynamic tumours, but the resulting tumour control could still be below the target levels. These results indicate that there is a complex relationship between the resolution of the dose-painting-by-numbers approaches and the dynamics of tumour oxygenation. Furthermore, the clinical success of hypoxia targeting strategies in the absence of adaptive approaches might be explained by changes in tumour radiation resistance through reoxygenation.
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| 10. |
- Dasu, Alexandru, et al.
(author)
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Impact of increasing irradiation time on the treatment of prostate cancers
- 2015
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In: World Congress on Medical Physics and Biomedical Engineering, June 7-12, 2015, Toronto, Canada. - Cham : Springer. - 9783319193861 - 9783319193878 ; 51, s. 490-493
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Conference paper (peer-reviewed)abstract
- This study aimed to investigate the expected impact of intrafraction repair during increasing irradiation times for the treatment of prostate cancers. Lengthy sessions are indeed expected for some advanced irradiation techniques capable to deliver the large fractional doses required by the increased fractionation sensitivity of the prostates. For this purpose, clinically-derived parameters characterizing repair rates and dose response curves for prostate tumors have been used to calculate the expected loss of effectiveness when increasing the irradiation time. The results have shown that treatment sessions lasting more than about 20 to 40 minutes could reduce the probability of biochemical control of prostate tumors by more than 20 to 30 percentage points. These results are in agreement with some observed clinical results and therefore they suggest that treatment durations in prostate radiation therapy should be carefully recorded in order to explicitly account for intrafraction repair, especially when irradiation techniques make use of multiple beams and imaging sessions. Failure to do so might overestimate the expected effectiveness of the treatment and could lead to disappointing clinical results precisely from the demanding treatment modalities expected to increase the therapeutic gain in prostate radiotherapy.
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