A total of 149 patients admitted for elective colorectal surgery were randomly allocated to receive preoperative mechanical bowel preparation (group 1) or no mechanical bowel preparation (group 2). All patients received antimicrobial prophylaxis with cephalothin and metronidazole. The overall incidence of wound infection was 17.4 per cent (24 per cent for group 1, 12 per cent for group 2) and that of dehiscence 7.4 per cent (10 per cent for group 1, 5 per cent for group 2). The incidence of wound infection was significantly higher in group 1 (P < 0.05) but that of anastomotic dehiscence did not differ significantly between groups. Mechanical bowel preparation is unnecessary and may be harmful in terms of preventing wound infection and anastomotic dehiscence in patients undergoing elective colorectal surgery.

No abstract

Of 34 patients with massive lower intestinal bleeding, 17 (11 men and 6 women, age range 33-85 years; mean 64.8 years) were diagnosed as having angiodysplasia of the colon. The diagnosis was made by colonoscopy and the lesions were treated successfully by fulguration in 13 (86.6 per cent) of 15 patients. Two of the 17 patients underwent surgical resection of the involved intestinal segment. One patient still has sporadic intestinal haemorrhage, and another patient died from bleeding of the left colon after blind right colectomy. The remaining 13 patients have had no further bleeding in the 1-7 years following colonoscopic fulguration. Colonoscopy is a useful method of diagnosing angiodysplasia of the colon and affords the possibility of treatment.

In order to evaluate the effect of pentagastrin on the motor activity of the sigmoid and rectum in patients with Chagas’ disease, manometric studies were performed on 22 chagasic patients, 11 without and 11 with megacolon, and 11 control subjects. Pentagastrin had a stimulating effect on the sigmoid and rectum in control subjects as well as in chagasic patients without megacolon. In chagasic patients with megacolon, pentagastrin had no effect on sigmoid or rectum motility, probably as a result of the intrinsic denervation known to occur in this disease. The findings suggest that the motor effect of pentagastrin on the human sigmoid and rectum depends on the myenteric nervous pathways.

Arti cial intelligence (AI) is an innovative tool that is revolutionising healthcare and medical physics, possibly impacting clinical practices, research, and the profession. The relevance of AI and its impact on the clinical practice and routine of professionals in medical physics were evaluated by medical physicists and researchers in this eld. An online survey questionnaire was designed for distribution to professionals and students in medical physics around the world. In addition to demographics questions, we surveyed opinions on the role of AI in medical physicists' practice, the possibility of AI threatening/disrupting the medical physicists' practice and career, the need for medical physicists to acquire knowledge on AI, and the need for teaching AI in postgraduate medical physics programmes. The level of knowledge of medical physicists on AI was also consulted. A total of 1019 responders from 94 countries participated. More than 85% of the responders agree that AI will play an essential role in medical physicists' practice. AI should be taught in the postgraduate medical physics programmes, and that more applications such as quality control, treatment planning will be performed by AI. Half of them thought AI would not threaten/disrupt the medical physicists' practice. AI knowledge was mainly acquired through self-taught and work-related activities. Nonetheless, many (40%) admitted that they have no skill in AI. The general perception of medical physicists is that AI is here to stay, and it will in uence our practice. Medical physicists should be prepared with education and training for this new reality.

The experimental method developed in this work allows simple positioning and alignment of a spectrometer for x-ray spectra measurements given the geometrical constraints and maintenance of the original configurations of mammography machines.

No abstract

According to the International Commission on Radiation Units and Measurements (ICRU), the relationship between effective dose and incident air-kerma is complex and depends on the attenuation of x-rays in the body. Therefore, it is not practical to use this quantity for shielding design purposes. This correlation is adopted in practical situations by using conversion coefficients calculated using validated mathematical models by the ICRU. The ambient dose equivalent, H*(10), is a quantity adopted by the IAEA for monitoring external exposure. Dose constraint levels are established in terms of H*(10), while the radiation levels in radiometric surveys are calculated by means of the measurements of air-kerma with ion chambers. The resulting measurements are converted into ambient dose equivalents by conversion factors. In the present work, an experimental study of the relationship between the air-kerma and the operational quantity ambient dose equivalent was conducted using different experimental scenarios. This study was done by measuring the primary x-ray spectra and x-ray spectra transmitted through materials used in dedicated chest radiographic facilities, using a CdTe detector. The air-kerma to ambient dose equivalent conversion coefficients were calculated from these measured spectra. The resulting values of the quantity ambient dose equivalent using these conversion coefficients are more realistic than those available in the literature, because they consider the real energy distribution of primary and transmitted x-ray beams. The maximum difference between the obtained conversion coefficients and the constant value recommended in national and international radiation protection standards is 53.4%. The conclusion based on these results is that a constant coefficient may not be adequate for deriving the ambient dose equivalent.