Biomedical subjects

M Benati

Publications and source records attributed to M Benati.

4 recordsLinked to original sources

PubMed1994

[In vivo dosimetry and radiographic confirmation in radiotherapy of Hodgkin's lymphoma].

In September 1991 a protocol for quality control of large shaped irradiation fields was started in our department. In vivo dosimetry with semiconductor detectors was used to measure the absorbed dose and patient positioning was checked with portal films weekly. First, we set a computed dosimetric system yielding dosimetric values in real time and allowing their easy storage. Then, we calibrated the diodes and determined the correction factors for each of them outside standard conditions. Entrance dose, exit dose and midline dose were measured in 62 patients undergoing supradiaphragmatic radiation therapy for Hodgkin's lymphoma. The exist dose was measured weekly to assess treatment repeatability. High agreement was observed between measured and calculated doses; repeatability was also high, since only 6% of exit dose measurements exceeded 5% of the first determination. In 33 patients portal films were obtained in the first treatment session, and thereafter weekly, to assess mispositioning relative to simulation (reproducibility) and from one session to another (repeatability). A small systematic error was detected in both longitudinal (x = -3 mm; SD = 3.7 mm) and transverse (x = -2 mm; SD = 3.4 mm) directions. Statistically significant errors (> 6 mm) were observed in 14% of patients. Reproducibility was excellent. The protocol reported on in this paper not only helps avoid systematic dosimetric and/or positioning errors in the patients, but also helps identify the main causes of uncertainty and thus remove them.

Hodgkin Disease↗

PubMed1980

Anthropomorphic robotics. I. Representing mechanical complexity.

A study of the fundamental principles upon which manipulation dexterity is based cannot help mixing robotic and neurophysiological concepts. A preliminary step in this study consists of trying to understand the complexity of manipulation dynamics. Though complexity shows itself in the massive number of elements of kinematic and dynamic equations, the fundamental simplicity of the underlying mechanical laws suggests to look for a structure, particularly from the computational point of view. Accordingly, a working computational model is proposed that organizes the massive computational load into a structure which is composed of a small number of computational units and lends itself to parallel computation.

Arm↗

PubMed1980

Anthropomorphic robotics. II. Analysis of manipulator dynamics and the output motor impedance.

An important factor in trying to capture the complexity of many manipulation problems is the notion of Output Motor Impedance, i.e., the relationship between a set of disturbing forces and the resulting variation in arm configuration. The functional significance of such force/displacement characteristics is investigated, showing how several aspects of different manipulation tasks (holding against gravity, inserting, fast moving, and throwing) can be naturally described in terms of appropriate modulation of the impedance characteristics of the manipulator. For this reason, impedance modulation can be considered an integral part of motor control.

Arm↗

PubMedDate not supplied

Single-dose oral ciprofloxacin plus parenteral metronidazole for perioperative antibiotic prophylaxis in colorectal surgery.

From 1983 until 1990 our standard antibiotic prophylaxis in colorectal surgery has been 80 mg gentamicin plus 500 mg metronidazole, both administered intravenously at the beginning of anesthesia, and then 80 mg gentamicin every 8 h for 3 days. In this time period, 718 patients undergoing elective colorectal surgery by abdominal approach were treated with this prophylactic procedure. The mean wound infection rate was 13.4% with no significant differences between years. In the present study, including 100 adult patients, intravenous gentamicin has been replaced by a single oral dose of 750 mg ciprofloxacin randomly administered 1, 2 or 3 h (+/- 30 min) before anesthesia. All other procedures remained unchanged including intravenous metronidazole. In order to correlate an eventual infection with the actual tissue concentrations during surgery, samples of colon, peritoneum, muscle, subcutaneous fat and skin were obtained from all patients and assayed by HPLC. In only 3 cases (3% of them casuistic) was a wound infection observed, 2 of minor importance and 1 case with wound dehiscence. This infection rate is significantly lower than 13.4% obtained with our previous standard regimen, and lower than the 9% wound infection rate considered to be the 'gold standard' for elective colon resections. The effective ciprofloxacin concentrations in tissues were usually notably higher than the MICs of the pathogens commonly observed in surgical infections of colorectal surgery. By far the highest ciprofloxacin concentrations were observed in colon tissue which may explain the absence of anastomotic dehiscence or peritoneal sepsis in our series.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗