Intercomparisons as An Important Element of Quality Assurance in Metrology of Ionising Radiation

Intercomparisons are important activities performed to ensure that the services provided by calibration laboratories to end-users follow internationally accepted standards. Ionizing radiation dosimetry intercomparisons are usually of two types - postal thermoluminescent dosimeter intercomparisons and ionization chamber calibration intercomparisons. In this paper, both types of intercomparisons are analysed together with the results of seven years of participation in such intercomparisons. Several discrepancies were discovered as a result of intercomparisons analysis and the resolution of the discrepancies was discussed

Tumor response and patient outcome after preoperative radiotherapy in locally advanced non-inflammatory breast cancer patients

Purpose: The purpose of this analysis was to assess the tumor response and long-term outcome in patients treated with preoperative radiotherapy (PRT) without systemic therapy. Methods: Between 1997 and 2000, 134 patients with non-inflammatory locally advanced breast cancer (LABC) were treated with PRT. The tumor dose was 45 Gy in 15 fractions to the breast and to regional lymph nodes over 6 weeks. Radical mastectomy was performed 6 weeks after PRT to all patients and adjuvant systemic therapy was administered as per protocol. The measures of disease outcome were overall survival (OS) and disease-free survival (DFS) which estimated using the Kaplan-Meier method. Results: Median follow-up was 74 months (range 4-216). Objective clinical tumor response after PRT was observed in 77.6% of the patients. Clinical complete tumor response (cCR) was achieved in 21.6% of the patients. Pathological CR in the breast was achieved in 15% of the patients. The 5- and 10-year OS were 55.1 and 37.8%, respectively. The 5- and 10-year DFS were 39.2 and 27%, respectively. Patients who achieved cCR had significantly longer OS in comparison with patients achieving clinical partial response (cPR) and clinical stable disease (cSD). Similarly, DFS of patients in the cCR group was longer compared with patients with cPR and cSD, yet without statistical significance. Conclusions: Our results showed that local control in LABC patients achieved by primary PRT, followed by radical mastectomy was comparable with the results reported in the literature. Complete pathologic response to PRT identified a subgroup of patients with a trend toward better DFS and OS

Primary pericardial malignant mesothelioma and response to radiation therapy

We report a case of a primary pericardial malignant mesothelioma. A 59-year-old male presented with episodic chest pain and dyspnea on exertion. Cardiac magnetic resonance imaging revealed a large mass in the pericardium attached to the right ventricle. Partial resection of the mass was undertaken revealing malignant mesothelioma, byphasic type. The patient was treated with chemotherapy intermittently over a period of 3 years, but his disease continued to progress. The patient was then treated with definitive radiation therapy to 64 Gy to the primary tumor using a six field 3D conformal technique. The patient remains free of progressive disease 86 months from the time of diagnosis and 50 months from the completion of his radiotherapy

Impact of renal impairment on atrial fibrillation: ESC-EHRA EORP-AF Long-Term General Registry

Background: Atrial fibrillation (AF) and renal impairment share a bidirectional relationship with important pathophysiological interactions. We evaluated the impact of renal impairment in a contemporary cohort of patients with AF. Methods: We utilised the ESC-EHRA EORP-AF Long-Term General Registry. Outcomes were analysed according to renal function by CKD-EPI equation. The primary endpoint was a composite of thromboembolism, major bleeding, acute coronary syndrome and all-cause death. Secondary endpoints were each of these separately including ischaemic stroke, haemorrhagic event, intracranial haemorrhage, cardiovascular death and hospital admission. Results: A total of 9306 patients were included. The distribution of patients with no, mild, moderate and severe renal impairment at baseline were 16.9%, 49.3%, 30% and 3.8%, respectively. AF patients with impaired renal function were older, more likely to be females, had worse cardiac imaging parameters and multiple comorbidities. Among patients with an indication for anticoagulation, prescription of these agents was reduced in those with severe renal impairment, p <.001. Over 24 months, impaired renal function was associated with significantly greater incidence of the primary composite outcome and all secondary outcomes. Multivariable Cox regression analysis demonstrated an inverse relationship between eGFR and the primary outcome (HR 1.07 [95% CI, 1.01–1.14] per 10 ml/min/1.73 m2 decrease), that was most notable in patients with eGFR <30 ml/min/1.73 m2 (HR 2.21 [95% CI, 1.23–3.99] compared to eGFR ≥90 ml/min/1.73 m2). Conclusion: A significant proportion of patients with AF suffer from concomitant renal impairment which impacts their overall management. Furthermore, renal impairment is an independent predictor of major adverse events including thromboembolism, major bleeding, acute coronary syndrome and all-cause death in patients with AF

Unsteady pressures influenced by trapped air pockets in water-filled pipelines

Trapped air pockets may cause severe operational problems in water-filled pipelines. This paper investigates the dynamic behaviour of a single trapped air pocket. A single air pocket creates distinct changes of amplitude, shape and timing of unsteady flow pressure waves when it is located at some point in a pipeline. The severity of the resulting hydraulic transients depends on the size, pressure and position of the trapped air pocket. In this paper, the air pocket is incorporated as a boundary condition in the discrete gas cavity model (DGCM) that also considers the effects of unsteady skin friction. Two distinct case studies are presented: (1) start-up test case (flow starting from rest) and (2) shut-down test case (flow stoppage). The start-up test case has been performed in the University of Montenegro pipeline apparatus (length 55 m, internal diameter 18 mm). A trapped air pocket is confined at the downstream end of the pipeline. The transient event is initiated by rapid opening of a valve positioned at the initial air/water interface. The shut-down test case has been carried out in the University of Adelaide laboratory apparatus (length 37 m, internal diameter 22 mm). A trapped gas pocket is maintained near the midpoint of the pipeline. The shut-down event is initiated by rapid closure of the downstream-end valve. Results of numerical simulations and laboratory investigations are presented and they show profound effects of unsteady skin friction on pressure histories