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G Ferrigno

Publications and source records attributed to G Ferrigno.

32 records · Page 2Linked to original sources
PubMed1996

Chest wall and lung volume estimation by optical reflectance motion analysis.

Estimation of chest wall motion by surface measurements only allows one-dimensional measurements of the chest wall. We have assessed on optical reflectance system (OR), which tracks reflective markers in three dimensions (3-D) for respiratory use. We used 86 (6-mm-diameter) hemispherical reflective markers arranged circumferentially on the chest wall in seven rows between the sternal notch and the anterior superior iliac crest in two normal standing subjects. We calculated the volume of the entire chest wall and compared inspired and expired volumes with volumes obtained by spirometry. Marker positions were recorded by four TV cameras; two were 4 m in front of and two were 4 m behind the subject. The TV signals were sampled at 100 Hz and combined with grid calibration parameters on a personal computer to obtain the 3-D coordinates of the markers. Chest wall surfaces were reconstructed by triangulation through the point data, and chest wall volume was calculated. During tidal breathing and vital capacity maneuvers and during CO2-stimulated hyperpnea, there was a very close correlation of the lung volumes (VL) estimated by spirometry [VL(SP)] and OR [VL(OR)]. Regression equations of VL(OR) (y) vs. VL(SP) (x, BTPS in liters) for the two subjects were given by y = 1.01x-0.01 (r = 0.996) and y = 0.96x + 0.03 (r = 0.997), and by y = 1.04x + 0.25 (r = 0.97) and y = 0.98x + 0.14 (r = 0.95) for the two maneuvers, respectively. We conclude spirometric volumes can be estimated very accurately and directly from chest wall surface markers, and we speculate that OR may be usefully applied to calculations of chest wall shape, regional volumes, and motion analysis.

Humans↗
PubMed1996

Optoelectronic techniques for patient repositioning in radiotherapy.

In modern radiotherapy practice, patient mispositionings and movements at therapy units are considered one of the major source of error in the irradiation and, consequently, a decisive factor in relapse rate and in radiation damages occurrence. Movement analysis system ELITE has been used to carry out a new conceived control on patient repositioning procedure and to implement an automatic correction of the detected position errors. Two marker disposition models have been defined for the supine position with reliable and easily identifiable body landmarks. Analytical comparison between current and reference 3D co-ordinates of these points has constituted the core of the whole method. The detection of patient's breathing phases has allowed to synchronize the co-ordinates calculation to patient's FRC, increasing accuracy and reliability of the comparison. Results point out the relative accuracy of the commonly adopted optical laser repositioning systems and confirm the significant role that ELITE can have in radiotherapy, in order to reach a suitable tradeoff between a quick irradiation set-up and a clinically correct patient irradiation.

Least-Squares Analysis↗
PubMed1996

A new method for 3D optical analysis of chest wall motion.

A method for kinematic analysis of chest wall motion is presented, based on a TV-image processor which allows a three-dimensional assessment of volume change of the trunk by automatically computing the co-ordinates of several passive markers placed on relevant landmarks of the thorax and abdomen. The parallel computation used for the image processing allows a real time recognition of the passive markers with the necessary accuracy. A geometric model also allows the on-line computation of the contribution to the chest volume by the different parts. For this purpose the model is based on 96 tetrahedrons which can be grouped into 16 compartments and into four sections representing: upper thorax (reflecting the action of neck and parasternal muscles and the effect of pleural pressure), lower thorax (reflecting the action of diaphragm and the effect of pleural and abdominal pressure), upper and lower abdomen (reflecting the actions of diaphragm and abdominal muscles). The volume can also be split into two vertical sections pointing out asymmetrics between the right and left side. The method is non-invasive, non-ionizing and leaves the subject maximum freedom of movement during the test, thus being suitable for routine clinical analysis. The monitoring of the subject can be prolonged in time and can be performed in different postures: standing, sitting, supine and lying on one side. The method was tested on eight healthy subjects showing good accuracy, reliability and reproducibility.

Biomechanical Phenomena↗
PubMed1994

Three-dimensional optical analysis of chest wall motion.

A method for kinematic analysis of chest wall motion is presented, based on a television-image processor that allows a three-dimensional assessment of volume change of the trunk by automatically computing the coordinates of several passive markers placed on relevant landmarks of the thorax and abdomen. The parallel computation used for the image processing allows for a real time recognition of the passive markers with the necessary accuracy. A geometric model also allows the online computation of the contribution to the chest volume by the different parts. For this purpose, the model presented here is based on 54 tetrahedrons that can be grouped into 9 compartments and 3 sections representing 1) upper thorax (mainly reflecting the action of neck and parasternal muscles and the effect of pleural pressure), 2) lower thorax (mainly reflecting the action of diaphragm and the effect of pleural and abdominal pressure), and 3) abdomen (mainly reflecting the actions of diaphragm and abdominal muscles). By this model, the volume can also be split into three vertical sections pointing out asymmetries between the right and left sides. The method is noninvasive, nonionizing, and leaves the subject maximum freedom of movement during the test, thus being suitable for routine clinical analysis. The monitoring of the subject can be prolonged in time and can be performed in different postures: standing, sitting, and supine. The method was tested on 12 healthy subjects showing its good accuracy, reliability, and reproducibility.

Abdomen↗
PubMed1994

[Experiences with sclerostomy with the Holmium laser].

The THC-YAG laser (holmium laser) war used to perform ab externo sclerostomies in patients affected by various types of glaucoma. This approach was employed in 48 eyes with diagnoses of medically uncontrolled chronic open angle glaucoma, plateau iris or neovascular glaucoma. Post-operatively, 5-FU was injected. At the tend of the follow-up (mean 10.22 +/- 3.4 months), in 25 eyes (52.1%) the IOP was under control without medical therapy. In 12 eyes (25.0%) it was necessary to use antiglaucomatous topical therapy, and in 11 eyes (22.9%) the IOP was uncontrolled despite therapy. The authors stress the importance of a correct pharmacological protocol before and after operation and describe the surgical technique. They confirm the validity of this approach, owing to its minical invasiveness, the possibility of repeating the procedure, and the low complication rate.

Aged↗
PubMed1992

Comparison between the more recent techniques for smoothing and derivative assessment in biomechanics.

When analysing and evaluating human motion, two strictly interconnected problems arise: the data smoothing and the determination of velocities and accelerations from displacement data. Differentiating procedures magnify the noise superimposed on the useful kinematic data. A smoothing procedure is thus required to reduce the measurement noise before the differentiation can be carried out. In the paper two techniques for derivative assessment are presented, tested and compared. One of these is the procedure known as one of the best automatic smoothing and differentiating techniques: generalised cross validatory spline smoothing and differentiation (GCVC). The other, which has recently been presented, features an automatic model-based bandwidth-selection procedure (LAMBDA). The procedures have been tested with signals presented by other authors and available in the literature, by test signals acquired using the ELITE motion analyser and by synthetic data. The results show better or similar performance of LAMBDA compared with GCVC. In the cases in which the natural conditions at the signal boundaries are not met GCVC gives bad results (especially on the third derivative) whereas LAMBDA is not affected at all. Moreover, analysis time is dramatically lower for LAMBDA.

Biomechanical Phenomena↗
PubMed1990

Technique for the evaluation of derivatives from noisy biomechanical displacement data using a model-based bandwidth-selection procedure.

Smoothing and differentiation of noisy signals are common problems whenever it is difficult or impossible to obtain derivatives by direct measurement. In biomechanics body displacements are frequently assessed and these measurements are affected by noise. To avoid high-frequency noise magnification, data filtering before differentiation is needed. In the approach reported here an autoregressive model is fitted to the signal. This allows the evaluation of the filter bandwidth and the extrapolation of the data. The extrapolation also reduces edge effects. Low-pass filtering is performed in the frequency domain by a linear phase FIR filter and differentiation is performed in the frequency domain. The reported results illustrate the accuracy of the algorithm and its speed (mainly due to the use of the FFT algorithm). Automatic bandwidth selection also guarantees the homogeneity of the results.

Algorithms↗
PubMed1990

An algorithm for 3-D automatic movement detection by means of standard TV cameras.

An algorithm for the computation of 3-D coordinates (space intersection) of marked points on a moving subject surveyed by a couple of TV cameras is presented herein. It has been designed in order to meet the requirements of routinary analysis in biomechanic laboratories. 3-D geometrical arrangement of the TV cameras (space resection) is obtained by means of a method which is based on an iterative least-squares estimation and requires little time for calibration operations; 3-D coordinates are computed by means of a fast geometrical intersection algorithm. The whole algorithm has been extensively used in different laboratories and results on its reliability and accuracy are reported.

Algorithms↗
PubMed1987

Changes in spatial scale in drawing and handwriting: kinematic contributions by proximal and distal joints.

The coordination of arm and hand motions was studied in tasks involving drawing and handwriting movements of different amplitudes. To this end, pen motion was recorded by means of a digitizing table, while the positions of different markers on the limb were monitored by the ELITE system. It was found that the amplitude of shoulder and elbow angular motions scales roughly with the size of the figure drawn or of the script, whereas the amplitude of wrist and finger motions is small, independent of size. Consequently, the larger the limb movement, the smaller the magnitude of the contributions by motions at distal joints relative to that at proximal joints. Furthermore, while shoulder and elbow motions are tightly coupled (constant phase relation), motions at distal joints are loosely coupled to those at the proximal joints (variable phase relation). On the other hand, motion at distal joints increases the accuracy of the movement, as indicated by the smaller variability of pen trajectories compared to that of wrist trajectories.

Art↗
PubMedDate not supplied

Motor coordination in weightless conditions revealed by long-term microgravity adaptation.

The functional approach to studying human motor systems attempts to give a better understanding of the processes behind planning movements and their coordinated performance by relying on weightlessness as a particularly enlightening experimental condition. Indeed, quantitative monitoring of sensorimotor adaptation of subjects exposed to weightlessness outlines the functional role of gravity in motor and postural organization. The recent accessibility of the MIR Space Station has allowed for the first time experimental quantitative kinematic analysis of long-term sensorimotor and postural adaptation to the weightless environment though opto-electronic techniques. In the frame of the EUROMIR'95 Mission, two protocols of voluntary posture perturbation (erect posture, EP; forward trunk bending, FTB) were carried out during four months of microgravity exposure. Results show that postural strategies for quasistatic body orientation in weightlessness are based on the alignment of geometrical body axes (head and trunk) along external references. A proper whole body positioning appears to be recovered only after months of microgravity exposure. By contrast, typically, terrestrial strategies of co-ordination between movement and posture are promptly restored and used when performing motor activities in the weightless environment. This result is explained under the assumption that there may be different sensorimotor integration processes for static and dynamic postural function and that the organisation of coordinated movement might rely stably on egocentric references and kinematics synergies for motor control.

Adaptation, Physiological↗
PubMedDate not supplied

Quantitative analysis of motion control in long term microgravity.

In the frame of the 179-days EUROMIR '95 space mission, two in-flight experiments have foreseen quantitative three-dimensional human movement analysis in microgravity. For this aim, a space qualified opto-electronic motion analyser based on passive markers has been installed onboard the Russian Space Station MIR and 8 in flight sessions have been performed. Techhology and method for the collection of kinematics data are described, evaluating the accuracy in three-dimensional marker localisation. Results confirm the suitability of opto-electronic technology for quantitative human motion analysis on orbital modules and raise a set of "lessons learned", leading to the improvement of motion analyser performance with a contemporary swiftness of the on-board operations. Among the experimental program of T4, results of three voluntary posture perturbation protocols are described. The analysis suggests that a short term reinterpretation of proprioceptive information and re-calibration of sensorimotor mechanisms seem to end within the first weeks of flight, while a continuous long term adaptation process allows the refinement of motor performance, in the frame of never abandoned terrestrial strategies.

Adaptation, Physiological↗
PubMedDate not supplied

[Automatic opto-electronic control of patient position in radiotherapy for breast carcinoma].

INTRODUCTION: We report on the technical and clinical validation of a system for real-time analytical control of patient position at simulation and treatment units in radiotherapy. MATERIAL AND METHODS: The positioning control system uses a technology for motion analysis consisting of an optical component (a pair of TV cameras) and of a unit for real-time image processing. The system can provide real-time (up to 100 times a second) three-dimensional (3D) coordinates of a set of passive markers (small plastic hemispheres, 5 mm O) previously positioned on the patient and located within the field of view of the system's TV cameras. The method for positioning quality control is based on the analytical comparison between the current positions of the set of markers placed on the patient's skin and a corresponding reference pattern, the latter acquired at the end of the simulation procedure or at the first irradiation session. The system was used at the Radiotherapy Division of the European Institute of Oncology for the analytical control of repositioning in three patients submitted to irradiation after conservative surgery (quadrantectomy) for breast cancer. This showed the clinical feasibility of both the technology and the method, and permitted to quantify improvement in patient positioning relative to current repositioning procedures. In particular, the possibility to evaluate the patient's breathing phases allowed to distinguish the different factors (repositioning inaccuracies and cyclic and random patient movements) contributing to global localization errors. RESULTS: This method is independent of physical and geometrical irradiation parameters and permits efficient real-time quantitative control of specific repositioning quality and of actual patient immobility during irradiation. Assessment of the accuracy of conventional repositioning methods based on laser alignment showed a fair performance of the optical centering procedure (with 3D displacements < 5 mm) only for the markers placed close to the skin landmarks used for laser alignment. On the contrary, the markers within the irradiation field but not directly controlled during the repositioning procedure exhibited localization errors > 5 mm; this happened even though the inaccuracies related to patient's breathing movements had been excluded from analysis. Moreover, quantitative assessment of global localization errors confirmed the high influence of breathing movements on the position repeatability and maintenance. In this case, even the markers which were on average well repositioned turned out to be significantly displaced during the radiation dose delivery. CONCLUSIONS: Our results confirm that real-time motion analysis based on opto-electronic techniques can play a crucial role as a means of improving patient positioning and assessing immobility. Thus, the system permits to quantify errors in target volume localization, which permits to adopt suitable countermeasures to reduce uncertainties during actual irradiation. This is a crucial requirement, particularly when the complexity of the irradiation geometry (conformal radiotherapy) or radiation type (hadrontherapy) calls for optimal application of the simulated treatment plan to each actual irradiation session.

Breast Neoplasms↗