Analysis of polychlorinated biphenyl residues in human plasma by gas chromatography-mass spectrometry

A method for the determination of seven polychlorinated biphenyl residues in plasma by gas chromatography-mass spectrometry was developed. The analytes were isolated from human plasma by liquid-liquid extraction, followed by solid-phase extraction, and separation on an HP5 Trace column. Ionization mode was electronic impact, and selected ion storage was used for isolation and quantitation of the compounds. The method was evaluated for its analytical performances and therefore applied to monitor the prevalence of these seven polychlorinated biphenyl residues in a female population. Eighty samples were analyzed, and 82.5% presented detectable amounts of at least one residue. For the population study, results were reported on a lipid-adjusted basis. Because the proposed method is satisfying and seems to be suitable for the quantitation of PCB congeners in a general population, epidemiological studies to evaluate the widespread contamination with these environmental compounds can be proposed

Radiation TherapisTs Radiographer (RTTs) and risk management in radiotherapy: An international survey.

peer reviewed[en] PURPOSE: In order to study the role perception and the effective involvement of Radiation TherapisTs (RTTs) in risk management in radiotherapy, a survey was developed and distributed in five countries (France, Switzerland, Belgium, Ireland, the Netherlands). MATERIALS AND METHODS: The article presents the results of this survey and the comparison between the different countries. RESULTS: Overall, the results of the survey show a good involvement and perception of the RTTs around the risk management approach, although training in this area has yet to be systematized. CONCLUSION: Although with differences in the results between the participating countries, the survey seems to highlight the deployment of preventive actions that are evaluated as not very effective by the respondents and by the international scientific literature

Crossover of the patient satisfaction surveys, adverse events and patient complaints for continuous improvement in radiotherapy department

editorial reviewedObjective: The patient's needs and expectations can be assessed through satisfaction surveys, adverse event declarations and records of complaints. By cross-referencing individual complaints, satisfaction surveys and the adverse events received, we could get valuable information. The objective is to identify common elements of work between these different sources to improve care. Methods: A retrospective analysis of patients' complaints, surveys and adverse events was carried out in order to highlight common improvement items between these three sources of information. Results: A satisfaction survey was given to the patients at the end of their treatment, who filled it out and left it in the 'ad hoc' letterbox. At the end of December 2019, 4695 questionnaires had been collected (response rate 37%). In addition, since 2014, 1369 patients (∼20 patients per month) have been interviewed 'face to face' by the research nurse who assesses their satisfaction using open questions. At the same time, a collection of complaints and adverse events was carried out. All these data have been analysed and cross-checked in order to highlight areas for improvement and strengthen the safety and quality of care in our department. Conclusions: Collect and analyse satisfaction surveys, unexpected events and complaints constitute in our opinion, an effective tool to achieve patient empowerment. We aim for the patients to become a real player in their safety and involve in the overall effort to improve the quality of their radiotherapy treatment by reporting what does not meet their expectations

Commissioning Monte Carlo algorithm for robotic radiosurgery using cylindrical 3D-array with variable density inserts.

peer reviewed[en] INTRODUCTION: To commission the Monte Carlo (MC) algorithm based model of CyberKnife robotic stereotactic system (CK) and evaluate the feasibility of patient specific QA using the ArcCHECK cylindrical 3D-array (AC) with Multiplug inserts (MP). RESULTS: Four configurations were used for simple beam setup and two for patient QA, replacing water equivalent inserts by lung. For twelve collimators (5-60mm) in simple setup, mean (SD) differences between MC and RayTracing algorithm (RT) of the number of points failing the 3%/1mmgamma criteria were 1(1), 1(3), 1(2) and 1(2) for the four MP configurations. Tracking fiducials were placed within AC for patient QA. Single lung insert setup resulted in mean gamma-index 2%/2mm of 90.5% (range [74.3-95.9]) and 82.3% ([66.8-94.5]) for MC and RT respectively, while 93.5% ([86.8-98.2]) and 86.2% ([68.7-95.4]) in presence of largest inhomogeneities, showing significant differences (p<0.05). DISCUSSION: After evaluating the potential effects, 1.12g/cc PMMA and 0.09g/cc lung material assignment showed the best results. Overall, MC-based model showed superior results compared to RT for simple and patient specific testing, using a 2%/2mm criteria. Results are comparable with other reported commissionings for flattening filter free (FFF) delivery. Further improvement of MC calculation might be challenging as Multiplan has limited material library. CONCLUSIONS: The AC with Multiplug allowed for comprehensive commissioning of CyberKnife MC algorithm and is useful for patient specific QA for stereotactic body radiation therapy. MC calculation accuracy might be limited due to Multiplan's insufficient material library; still results are comparable with other reported commissioning measurements using FFF beams

Comparison between the WHO-CFICPS and the PRISMA classification of safety-related events in a radiation oncology department.

peer reviewed[en] INTRODUCTION: Describing Safety-Related Events (SREs) in a radiotherapy (RT) department and comparing WHO-CFICPS (World Health Organization's Conceptual Framework For The International Classification For Patient Safety) and PRISMA (Prevention and Recovery Information System for Monitoring and Analysis) methods for classifying SREs. METHODS: From February 2017 to October 2020, two Quality Managers (QMs) randomly classified 1173 SREs using 13 incident types of WHO-CFICPS. The same two QMs, reclassified the same SREs according to 20 PRISMA incident codes. Statistical analysis was performed to assess the association between the 13 incident types of WHO-CFICPS and the 20 PRISMA codes. The chi-squared and post-hoc tests using adjusted standardized residuals were applied to detect the association between the two systems. RESULTS: There was a significant association between WHO-CFICPS incident types and PRISMA codes (P < 0.001). Ninety-two percent of all SREs were categorized using 4 of 13 WHO-CFICPS incident types including Clinical Process/Procedure (n = 448, 38.2%), Clinical Administration (n = 248, 21.1%), Documentation (n = 226, 19.2%) and Resources/Organizational Management (n = 15,613.3%). According to PRISMA classification, 14 of the 20 codes were used to describe the same SREs. PRISMA captured 41 Humans Skill Slips from 226 not better defined WHO-CFICPS Documentation Incidents, 38 Human Rule-based behaviour Qualification from not better defined 447 Clinical Process/Procedure and 40 Organization Management priority events from 156 not better defined WHO-CFICPS Resources/Organizational Management events (P < 0.001). CONCLUSION: Although there was a significant association between WHO-CFICPS and PRISMA, The PRISMA method provides a more detailed insight into SREs compared to WHO-CFICPS in a RT department

Prediction of GTV median dose differences eases Monte Carlo re-prescription in lung SBRT.

peer reviewed[en] BACKGROUND AND PURPOSE: The use of Monte Carlo (MC) dose calculation algorithm for lung patients treated with stereotactic body radiotherapy (SBRT) can be challenging. Prescription in low density media and time-consuming optimization conducted CyberKnife centers to propose an equivalent path length (EPL)-to-MC re-prescription method based on GTV median dose. Unknown at the time of planning, GTV D50% practical application remains difficult. The current study aims at creating a re-prescription predictive model in order to limit conflicting dose value during EPL optimization. MATERIAL AND METHODS: 129 patients planned with EPL algorithm were recalculated with MC. Relative GTV_D50% discrepancies were assessed and influencing parameters identified using wrapper feature selection. Based on best descriptive parameters, predictive nomogram was built from multivariate linear regression. EPL-to-MC OARs near max-dose discrepancies were reported. RESULTS: The differences in GTV_D50% (median 10%, SD: 9%) between MC and EPL were significantly (p < .001) impacted by the lesion's surface-to-volume ratio and the average relative electronic density of the GTV and the GTV's 15 mm shell. Built upon those parameters, a nomogram (R2 = 0.79, SE = 4%) predicting the GTV_D50% discrepancies was created. Furthermore EPL-to-MC OAR dose tolerance limit showed a strong linear correlation with coefficient range [0.84-0.99]. CONCLUSION: Good prediction on the required re-prescription can be achieved prior planning using our nomogram. Based on strong linear correlation between EPL and MC for OARs near max-dose, further restriction on dose constraints during the EPL optimization can be warranted. This a priori knowledge eases the re-prescription process in limiting conflicting dose value

The Influence of Treatment Position (Prone vs. Supine) on Clip Displacement, Seroma, Tumor Bed and Partial Breast Target Volumes: Comparative Study

peer reviewedTo analyse the displacement of surgical clips in prone (Pr) position and assess the consequences on target volumes and integral dose of partial breast irradiation (PBI). 30 post-lumpectomy breast cancer patients underwent CT imaging in supine (Su) and Pr. Clip displacements were measured by the distances from the clips to a common fix bony reference point. On each dataset, the tumour bed (TB = clips ± seroma), clinical target volume (CTV = TB + 1.5 cm) and planning target volumes (PTV = CTV + 1 cm) for PBI were determined and the volume pairs were compared. Furthermore estimation of integral dose ratio (IDR) within the breast from tangential treatment was performed as the ratio of the irradiated breast volume and the volume encompassing all clips. Clips close to the chest wall (CW) in Su showed significantly less displacement in Pr. The mean volumes of seroma, CTV and PTV were significantly higher in Pr than in Su. The PTV volume difference (Pr-Su) was significantly higher in patients with presence of seroma, deep clips and TB location in the superior-internal-quadrant (SIQ) and at the junction of superior quadrants (jSQ). In a multivariate analysis two factors remained significant: seroma and TB localization in SIQ-jSQ. The IDR was significantly larger in Su than in Pr (7.6 vs. 4.1 p < 0.01). Clip displacements varied considerably with respect to their relative position to the CW. In selected patients Pr position potentially leads to a significant increase in target volumes of PBI. Tangential beam arrangement for PBI should be avoided, not only in Su but in Pr as well in case of clip-based target volume definition