Biomedical subjects

A M Di Nallo

Publications and source records attributed to A M Di Nallo.

5 recordsLinked to original sources

PubMed2006

MRI quality control tools for procedures and analyses.

Quality control in MRI includes acceptance tests on the installation of a new scanner and tests representative of the system's performance during clinical practice. The first tests are time consuming and carried out to evaluate the agreement of the system with the prescribed procurement specifications. The second tests identify the equipment malfunction requiring maintenance are not time consuming and are suited to a busy clinical scanner. The paper evaluates the feasibility of the AAPM protocols (1,2) and proposes procedures and practical tools to achieve this purpose. The MRI images, captured from the scanner and transferred in DICOM (Digital Imaging and Communications in Medicine) format by a local network, are analyzed by computerized worksheets and commercial software.

Calibration↗

PubMed2006

A possible quality control protocol for Doppler ultrasound for organizational time optimization.

Acceptance tests quantitatively determine equipment performance characteristics. Before a new probe is accepted, performance tests can be also used to compare performance of other probes. Routine performance tests verify device operational stability over the time. We developed an efficient and effective testing programme aiming to demonstrate changes in imaging performance relevant to clinical quantitative use of pulsed and colour Doppler. For each scanner-transducer tested, we introduced some quantitative and semi-quantitative parameters in relation to the clinical request for which the equipment was chosen. The proposed quantitative tests may also be used as qualitative tests, when it is suspected that scanner performance is deteriorating. The measurements, obtained with different units, differed also in the case of probes operating at the same depth and peak velocity. Without a quality control (QC) program, significant variations are likely to be reported when peak velocity of the same flow is measured with different instruments. Our experience suggests that modern digital equipments used in serial measurements may be stable over the time and that calibrated phantom may enable preventive identification of corrective action to units and probes. Manufacturers and independent laboratories applying a quality control protocol can increase our experience to recognize and deal with the involved problems.

Blood Flow Velocity↗

PubMed1994

A simple method to calculate the influence of dose inhomogeneity and fractionation in normal tissue complication probability evaluation.

PURPOSE: Since volumetric dose distributions are available with 3-dimensional radiotherapy treatment planning they can be used in statistical evaluation of response to radiation. This report presents a method to calculate the influence of dose inhomogeneity and fractionation in normal tissue complication probability evaluation. METHODS: The mathematical expression for the calculation of normal tissue complication probability has been derived combining the Lyman model with the histogram reduction method of Kutcher et al. [14] and using the normalized total dose (NTD) instead of the total dose. RESULTS: The fitting of published tolerance data, in case of homogeneous or partial brain irradiation, has been considered. For the same total or partial volume homogeneous irradiation of the brain, curves of normal tissue complication probability have been calculated with fraction size of 1.5 Gy and of 3 Gy instead of 2 Gy, to show the influence of fraction size. The influence of dose distribution inhomogeneity and alpha/beta value has also been simulated: considering alpha/beta = 1.6 Gy or alpha/beta = 4.1 Gy for kidney clinical nephritis, the calculated curves of normal tissue complication probability are shown. CONCLUSION: Combining NTD calculations and histogram reduction techniques, normal tissue complication probability can be estimated taking into account the most relevant contributing factors, including the volume effect.

Brain↗

PubMed1990

Practical experience in electromagnetic hyperthermia quality control procedures within the context of international guidelines.

Recent international guidelines on hyperthermia (HT) quality assurance have pointed out the necessity of defining standard operative procedures and technical checks to guarantee an accurate performance of HT treatments. In the present paper, experience is described of quality control procedures that are performed in agreement with the more general guidelines concerning thermometry, sensor positioning, phantoms, applicator characterisation, and electromagnetic (EM) radiation leakage. This practical experience comes from the use of equipment for superficial and loco-regional HT working in the range 13.56-915 MHz.

Evaluation Studies as Topic↗

PubMedDate not supplied

Electromagnetic interference by GSM cellular phones and UHF radios with intensive-care and operating-room ventilators.

The aim of this study was to evaluate the risks deriving from the interference by radio handsets (GSM cellular phones and UHF radios) with intensive-care and operating-room ventilators. Tests were conducted in three hospitals in Rome on 22 lung ventilators in accordance with the recommended practice ANSI C63.18-1997. When electromagnetic interference (EMI) effects occurred, the authors determined maximum interference distances. They also evaluated the distances at which the use of a given handset would result in a 5% and a 95% probability of interference. The degree of risk posed by each observed event was estimated, and safe distances are suggested. EMI events of varying degrees and natures were observed even with transmitters placed at a considerable distance. All observed effects were temporary. Only three ventilators of a certain model stopped working altogether and had to be reset.

Electromagnetic Fields↗