BriXS, a new X-ray inverse Compton source for medical applications.

MariX is a research infrastructure conceived for multi-disciplinary studies, based on a cutting-edge system of combined electron accelerators at the forefront of the world-wide scenario of X-ray sources. The generation of X-rays over a large photon energy range will be enabled by two unique X-ray sources: a Free Electron Laser and an inverse Compton source, called BriXS (Bright compact X-ray Source). The X-ray beam provided by BriXS is expected to have an average energy tunable in the range 20-180 keV and intensities between 1011 and 1013 photon/s within a relative bandwidth ΔE/E=1-10%. These characteristics, together with a very small source size (~20 µm) and a good transverse coherence, will enable a wide range of applications in the bio-medical field. An additional unique feature of BriXS will be the possibility to make a quick switch of the X-ray energy between two values for dual-energy and K-edge subtraction imaging. In this paper, the expected characteristics of BriXS will be presented, with a particular focus on the features of interest to its possible medical applications.

GEANT4 Monte Carlo simulations for virtual clinical trials in breast X-ray imaging: Proof of concept.

Virtual clinical trials (VCT) are in-silico reproductions of medical examinations, which adopt digital models of patients and simulated devices. They are intended to produce clinically equivalent outcome data avoiding long execution times, ethical issues related to radiation induced risks and huge costs related to real clinical trials with a patient population. In this work, we present a platform for VCT in 2D and 3D X-ray breast imaging. The VCT platform uses Monte Carlo simulations based on the Geant4 toolkit and patient breast models derived from a cohort of high resolution dedicated breast CT (BCT) volume data sets. Projection images of the breast and three-dimensional glandular dose maps are generated for a given breast model, by simulating both 2D full-field digital mammography (DM) and 3D BCT examinations. Uncompressed voxelized breast models were derived from segmented patient images. Compressed versions of the digital breast phantoms for DM were generated using a previously published digital compression algorithm. The Monte Carlo simulation framework has the capability of generating and tracking ~105 photons/s using a server equipped with 16-cores and 3.0 GHz clock speed. The VCT platform will provide a framework for scanner design optimization, comparison between different scanner designs and between different modalities or protocols on computational breast models, without the need for scanning actual patients as in conventional clinical trials.

Rotational radiotherapy of breast cancer with polyenergetic kilovoltage X-ray beams: An experimental and Monte Carlo phantom study.

PURPOSE: We investigated the feasibility of kilovoltage rotational radiotherapy for breast cancer (kV-EBRT) via Monte Carlo simulations and measurements on phantoms. METHODS: We derived the dose distributions for X-ray beams at 150 kV, 300 kVp and 320 kV irradiating breast cylindrical phantoms of 14 cm diameter, mimicking the pendant breast. Simulations were based on the Geant4 toolkit. The point-like X-ray source was rotated either over a full circle or on a limited arc around the phantom. We studied the influence on the surface dose of the distance between the tumor lesion to the skin, of the irradiation protocol (full scan or partial scan) and of the X-ray tube current modulation. RESULTS: Rotational kV-EBRT permitted a periphery-to-center dose ratio from 13% to 9% in homogeneous breast phantoms. Dose distributions in phantoms with off-center simulated lesions, showed a skin-to-tumor dose ratio of 16% and 34% for lesions at 3.25 and 5.25 cm from cylinder axis, respectively. Simulation of the X-ray tube current modulation during the rotation, permits to reach a dose ratio of 20% for the lesion located at 5.25 cm from phantom axis. CONCLUSIONS: We showed the possibility of using low-energy X-ray spectra for kV-EBRT with collimated beams, for obtaining a periphery-to-center dose ratio in the same order of conventional accelerator based megavoltage radiotherapy, when the irradiated area is localized in the center of the breast. For tumors localized near the breast border, we showed that the tube current modulation can be a good solution in order to reduce the skin-to-tumor dose ratio.

Monte Carlo calculation of monoenergetic and polyenergetic DgN coefficients for mean glandular dose estimates in mammography using a homogeneous breast model.

We computed normalized glandular dose (DgN) coefficients for mean glandular dose estimates in contemporary 2D mammography units, taking into account a homogeneous model for the breast which reflects recent literature reports. We developed a Monte Carlo code based on the simulation toolkit GEANT4 ver. 10.00. The breast was modelled as a cylinder with a semi-cylindrical section with a radius of 10 cm, enveloped in a 1.45 mm thick skin layer, as found out in recent reports in the analysis of breast computed tomography clinical scans. The compressed breast thickness was between 3 cm and 8 cm. The DgN coefficients were calculated for monoenergetic x-ray beams between 4.25 keV and 49.25 keV and were fitted with polynomial curves. Polyenergetic DgN coefficients were then computed for spectra obtained for various anode/filter combinations as adopted in routine clinical practice: Mo/Mo 30 µm (25-40 kV), Mo/Rh 25 µm (25-40 kV), Rh/Rh 25 µm (25-40 kV), W/Ag 50 µm (26-34 kV), W/Al 500 µm (26-38 kV), W/Al 700 µm (28-40 kV) and W/Rh 50 µm (24-35 kV). Monoenergetic DgN curve fit coefficients and polyenergetic DgNp coefficients were released for research and clinical work. Polyenergetic DgNp coefficients were 6% higher than those provided in the recent literature, on average. The differences range between -18% and 30%; up to 50% of the computed coefficients differed by less than 10%. The dataset of DgN coefficients are provided as tables for varying glandular fraction by mass and compressed breast thickness. Moreover, a computer code has been developed for generating user specific coefficients DgNp for user defined x-ray spectra up to 49 kV, calculated by spectral weighting from the dataset of monoenergetic DgN coefficients.

'True Day Case' Laparoscopic Cholecystectomy in a High-Volume Specialist Unit and Review of Factors Contributing to Unexpected Overnight Stay.

INTRODUCTION: Laparoscopic cholecystectomy (LC) is the gold standard treatment for gallstones. British Association of Day Case Surgery recommends at least 60% of LCs be performed as day cases. The aim of this study was to assess our rate of true day case LCs and review factors preventing same-day discharge. METHODS: We prospectively collected data of all elective LCs performed in a district general hospital over 32 months. RESULTS: 500 patients underwent LC during this period; 438 (88.2%) patients were planned day cases and 59 patients (11.8%) planned overnight stays. Of the planned day cases, 75.8% (n=332) were discharged on the same day and 106 (24.2%) had unexpected overnight stay (UOS). Most patients with BMI >35 and ASA3 planned day case patients were successfully discharged. Drain insertion, longer operations, and late recovery departure were the main reasons for UOS. There were more complications in this group compared to day cases. CONCLUSIONS: This unit has a high 'true day case' rate of 75.8%. High BMI and ASA3 should not be absolute contraindications to day case surgery. The majority of unexpected overnight stays are unavoidable but may be reduced by patient selection, stringent preoperative assessment, operation scheduling, and reduction in unnecessary drain insertion.

Elective "True Day Case" Laparoscopic Inguinal Hernia Repair in a District General Hospital: Lessons Learned from 1000 Consecutive Cases.

INTRODUCTION: Laparoscopic inguinal hernia repair (LIHR) is ideal for day case surgery. It is recommended that at least 70% should be day cases as a measure of cost-effectiveness. The aims of this study were to (i) assess the rate of true day case (TDC) surgery and (ii) identify predictors associated with unexpected overnight stay (UOS). METHODS: Data was collected prospectively on 1000 consecutive elective LIHR performed in a District General Hospital (DGH) over a 7-year period. Data was collected on baseline patient demographics, ASA grade, and intraoperative details. A multivariate analysis was performed in order to identify predictors of UOS. RESULTS: 1000 patients (927 males) underwent elective LIHR. Mean age was 57.3±15.2 years. 915 patients were planned as day case procedures. 822/915 day cases (89.8%) were discharged on the same day and 93 (10.2%) stayed overnight unexpectedly. Patient age, duration of procedure, and patient slot in the operating list were found to be independent predictors (p<0.05) of UOS. CONCLUSION: Our results demonstrate that LIHR is a "true" day case procedure in a DGH. Although some factors associated with UOS cannot be altered, careful patient selection and operating list planning are of paramount importance in order to minimise the burden on healthcare resources.

Photoelectrochemical evidence of nitrogen incorporation during anodizing sputtering--deposited Al-Ta alloys.

Anodic films were grown to 20 V on sputtering-deposited Al-Ta alloys in ammonium biborate and borate buffer solutions. According to glow discharge optical emission spectroscopy, anodizing in ammonium containing solution leads to the formation of N containing anodic layers. Impedance measurements did not evidence significant differences between the dielectric properties of the anodic films as a function of the anodizing electrolyte. Photoelectrochemical investigation allowed evidencing that N incorporation induces a red-shift in the light absorption threshold of the films due to the formation of allowed localized states inside their mobility gap. The estimated Fowler threshold for the internal photoemission processes of electrons resulted to be independent of the anodizing electrolyte confirming that N incorporation does not appreciably affect the density of states distribution close to the conduction band mobility edge. The transport of photogenerated carriers has been rationalized according to the Pai-Enck model of geminate recombination.

Systematic review and meta-analysis of single-incision versus conventional multiport appendicectomy.

BACKGROUND: The aim of this systematic review and meta-analysis was to compare clinical outcomes following single-incision laparoscopic appendicectomy (SILA) and conventional multiport laparoscopic appendicectomy (CLA) for the treatment of acute appendicitis. METHODS: An electronic search of MEDLINE, Embase, Web of Science and Cochrane Library databases was performed. Publications were included if they were clinical trials randomizing patients with appendicitis to SILA or CLA. Outcome measures evaluated included operating time, length of hospital stay, total postoperative complications, and, specifically, wound infection, intra-abdominal collection and ileus. Weighted mean difference was calculated for the effect size of SILA on continuous variables, and pooled odds ratios were calculated for discrete variables. RESULTS: The literature search identified seven randomized clinical trials that met the inclusion criteria for meta-analysis. In total, 1108 appendicectomies were included, 555 SILA and 553 CLA procedures. There were no significant differences between the groups in the incidence of total postoperative complications, wound infection, intra-abdominal collection, ileus or length of hospital stay. However, SILA was associated with a significantly longer operating time compared with CLA (weighted mean difference 6·96 (95 per cent confidence interval 3·79 to 10·12) min; P < 0·001). Insertion of an additional port was required in 7·6 per cent of patients undergoing SILA. CONCLUSION: SILA is a safe procedure for the treatment of acute appendicitis, with comparable clinical outcome to CLA when undertaken by experienced laparoscopic surgeons.

Randomized clinical trial of omega-3 fatty acid-supplemented enteral nutrition versus standard enteral nutrition in patients undergoing oesophagogastric cancer surgery.

BACKGROUND: Oesophagogastric cancer surgery is immunosuppressive. This may be modulated by omega-3 fatty acids (O-3FAs). The aim of this study was to assess the effect of perioperative O-3FAs on clinical outcome and immune function after oesophagogastric cancer surgery. METHODS: Patients undergoing subtotal oesophagectomy and total gastrectomy were recruited and allocated randomly to an O-3FA enteral immunoenhancing diet (IED) or standard enteral nutrition (SEN) for 7 days before and after surgery, or to postoperative supplementation alone (control group). Clinical outcome, fatty acid concentrations, and HLA-DR expression on monocytes and activated T lymphocytes were determined before and after operation. RESULTS: Of 221 patients recruited, 26 were excluded. Groups (IED, 66; SEN, 63; control, 66) were matched for age, malnutrition and co-morbidity. There were no differences in morbidity (P = 0·646), mortality (P = 1·000) or hospital stay (P = 0·701) between the groups. O-3FA concentrations were higher in the IED group after supplementation (P < 0·001). The ratio of omega-6 fatty acid to O-3FA was 1·9:1, 4·1:1 and 4·8:1 on the day before surgery in the IED, SEN and control groups (P < 0·001). There were no differences between the groups in HLA-DR expression in either monocytes (P = 0·538) or activated T lymphocytes (P = 0·204). CONCLUSION: Despite a significant increase in plasma concentrations of O-3FA, immunonutrition with O-3FA did not affect overall HLA-DR expression on leucocytes or clinical outcome following oesophagogastric cancer surgery. REGISTRATION NUMBER: ISRCTN43730758 (http://www.controlled-trials.com).

Postpneumonectomy esophageal fistula: a combined radiological-endoscopic technique.

We report a case of a 70-year-old man who presented with a long-standing esophagocutaneous fistula following a pneumonectomy for aspergilloma. Major surgical procedures, including a pectoralis major flap reconstruction, a pedicled omental transposition and a radial forearm flap transposition, failed to obliterate the fistula. Seven years after initial surgery the esophagocutaneous fistula was successfully treated by means of a minimally invasive joint endoscopic and radiological technique. A radiographic catheter was passed through the fistula. The catheter and the guide wire were manipulated into the esophageal defect and into the upper esophagus. Under endoscopic vision, the catheter was then advanced over the guide wire and out of the patient's mouth. A T-tube was sutured to the catheter outside the mouth, pulled down through the esophagus, and into the esophageal defect and out through the chest wall, leaving the T-part of the tube within the esophagus. The patient made a good recovery and was discharged 7 days later. He was able to resume oral intake 3 weeks after the procedure.

[Esophageal achalasia. Personal experience with 76 patients]. / Acalasia esofagea. Esperienza personale su 76 pazienti.

The Authors report their experience on 76 patients managed for oesophageal achalasia from 1973-1997. 65 patients have been surgically treated with Heller miotomy (19 cases) or miotomy with antireflux procedures (46 cases); 11 patients underwent an endoscopic pneumatic dilation. 54 patients, 43 surgically and 11 endoscopically treated, have been followed for a mean length of time of 6 years and 6 months. Complete cure or significant improvement of symptoms have been noted in 86% and 72.7% of patients treated respectively with surgery or pneumatic dilatation. The results have been evaluated according to the recent data from the literature and diagnostic and therapeutic aspects of primitive achalasia are discussed.

[Hartmann's procedure in colorectal tumors. Evolutions of the indications in a series of 46 patients]. / L'intervento di Hartmann nei tumori colo-rettali. Evoluzione delle indicazioni in una serie di 46 pazienti.

The Authors report a retrospective study of 46 cases of Hartmann's operation in order to analyze the changing indications to this procedure in the management of colo-rectal cancer. The Hartmann's is operation has been performed in 46 out of 723 patients (6.4%) with colorectal cancer treated surgically from 1973 to 1997. Data concerning the indications have been analyzed in two consecutive periods, from 1973 to 1985 and from 1986 to 1997, respectively. In the first period, the procedure has been performed in patients with neoplastic perforation (40% of Hartmann's cases), and in an elective basis in patients with locally invasive tumor or intra-abdominal metastasis (20%). Indications for the procedure in the period 1986-1997 have been locally invasive tumor and/or distant metastasis (52.8% of Hartmann's procedures), neoplastic perforation (22.2%), high surgical anaesthesiologic risk (22.2%) or intestinal obstruction (2.8%). In the second period it has been noted a decrease of the number of patients that underwent Hartmann's procedure for bowel obstruction, and an increase in the number of cases in which the operation was performed for neoplastic perforation, for local and/or distant diffusion, or for high surgical risk.

[Synchronous primary carcinoma of the colon. Diagnostic and therapeutic problems]. / II carcinoma primitivo sincrono del colon. Problemi diagnostici e terapeutici.

Seven hundred and twenty-three patients with colorectal carcinoma were treated consecutively from November 1973 to April 1997. Seven patients (0.96%) were found to have two colorectal carcinomas (synchronous carcinoma), located in separated colonic areas. Clinical histories were analyzed with reference to sex, age, symptoms, physical findings, disease localization, pathologic classification, and survival data. Preoperative diagnosis of synchronous lesions is difficult, being achieved in only 2 cases, but it is important for the proper treatment of patients. It is concluded that full examination of the colon in all patients presenting with primary colorectal cancer is mandatory and that colonoscopy should be used to effectively screen patients for synchronous cancers.

[The physiopathological and therapeutic aspects of esophageal diverticula]. / Aspetti fisiopatologici e terapeutici dei diverticoli dell'esofago.

The authors reviewed 23 surgical cases of symptomatic oesophageal diverticula. In Zenker's diverticula (7 cases) the surgical treatment consisted of extramucosal cricopharyngeal myotomy and diverticulectomy (6 patients) or diverticulum suspension (1 patient). The operations in epiphrenic (15 patients) and mid-thoracic (1 patient) diverticula were as follows: diverticulectomy, longitudinal extramucosal myotomy and antireflux surgery (11 cases); myotomy and antireflux surgery (4 cases); myotomy alone (1 patient). There was no operative mortality. Postoperative complications occurred in 3 patients (13%). 15 patients were followed for an average time of 60 months. None of them developed postoperative dysphagia. Pathogenesis, diagnostic methods and surgical options are discussed.