Comparison of an animal model of arteriovenous malformation with human arteriovenous malformation

This study assessed the blood flow and histological changes of an animal model of arteriovenous malformation (AVM) over 84 days in 71 rats, and compared the histological findings to 17 specimens of human AVM. Carotid–jugular fistula blood flow positively correlated with time. The maximum flow rate occurred at 42 days, at which time the nidus was considered mature and was histologically similar to human AVMs. Morphological similarities between the model and human AVM vessels included heterogeneously thickened walls, splitting of the elastic lamina, thickened endothelial layers, endothelial cushions, lack of tight junctions, loss of endothelial continuity, endothelial–subendothelial adherent junctions, and luminally directed filopodia. These findings support the theory that vascular changes in human AVMs are secondary to increased flow and provide a basis for using this model in studies of AVMs.7 page(s

Endothelial molecular changes in a rodent model of arteriovenous malformation : laboratory investigation

OBJECT: The cellular and molecular processes underlying arteriovenous malformation (AVM) development and response to radiosurgery are largely unknown. An animal model mimicking the molecular properties of AVMs is required to examine these processses. This study was performed to determine whether the endothelial molecular changes in an animal model of arteriovenous fistula (AVF) are similar to those in human AVMs. METHODS: Arteriovenous fistulas were created in 18 Sprague-Dawley rats by end-to-side anastomosis of the left jugular vein to the common carotid artery creating a model "nidus" of arterialized branching veins that coalesce into a "draining vein" (sigmoid sinus). Six control animals underwent sham operations. RESULTS: After 1 or 3 days, or 1, 3, 6, or 12 weeks, fresh-frozen sections of the fistula, nidus vessels, and contralateral vessels were studied immunohistochemically for thrombomodulin, von Willebrand factor, E-selectin, P-selectin, and vascular endothelial growth factor. CONCLUSIONS: The AVF model has a "nidus" with endothelial molecular changes similar to those observed in human AVMs, supporting its use as a model for studying the effects of radiosurgery on AVMs.8 page(s

Junior doctor evaluation of radiation oncology education and training in medical schools and prevocational training in Australia

The purpose of this study is to evaluate radiation oncology (RO)–specific education, confidence and knowledge of junior doctors in Australian teaching hospitals. A 38-item web-based survey was emailed to prevocational junior doctors working in Australian hospitals in New South Wales (NSW), Australian Capital Territory (ACT) and Queensland (QLD) between November 2017 and January 2018. The survey evaluated RO educational and clinical exposure of participants during medical school, and prevocational training and their confidence and knowledge of the specialty. A total of 183 respondents across 17 Australian hospital networks completed the survey. During medical school, 53.4% had RO incorporated into their formal curriculum, 19.5% had no formal lectures and 51.7% had never visited a RO department. As a junior doctor, 73.8% of respondents did not receive any formal RO education. When compared with other oncology specialties, fewer junior doctors were confident in consulting the RO team (21.0%) compared with medical oncology (42.0%), palliative care (75.2%) and haematology (40.1%). Majority of respondents (61.6%) showed limited understanding of radiation safety. On multivariate sub-group analysis, both confidence and knowledge in RO improved when RO was incorporated into the formal medical school curriculum. This survey highlights the current low confidence and poor knowledge standard amongst Australian junior doctors on RO due to inadequate teaching during medical school and prevocational training and suggests improvement through standardisation of formal RO curriculum teaching within medical school and prevocational training

Oncology and radiation oncology awareness in final year medical students in Australia and New Zealand

This study aimed to determine final year students’ core oncology and radiation oncology knowledge and attitudes about the quality of teaching in medical programmes delivered in Australia and New Zealand. Does the modern medical programme provide core oncology skills in this leading global cause of mortality and morbidity? An online survey was distributed between April and June 2018 and completed by 316 final year students across all 21 medical schools with final year cohorts in Australia and New Zealand. The survey examined teaching and clinical exposure, attitudes and core knowledge for oncology and radiation oncology. Several questions from a survey done of graduates in 2001 were repeated for comparison. We found that clinical exposure to oncology and its disciplines is low. Students rated oncology and haematology the worst taught medical specialties at medical school. Students reported the most confidence identifying when surgical management of cancer may be indicated and much lower levels of confidence identifying when systemic therapy and radiation therapy may be helpful. The majority of students had no formal course content on radiation therapy and more than one third of final year students erroneously believed that external beam radiation therapy turned patients radioactive. Exposure to oncology practice and the teaching of core oncology knowledge remains low for medical students in Australia and New Zealand. Many areas of oncology teaching and knowledge have worsened for medical students in Australia and New Zealand over the past 20\ua0years. Well-established gaps in the core oncology knowledge of medical graduates must be urgently addressed given the increasing incidence of cancer and ongoing underutilisation of radiation therapy in particular

Superior target volume and organ stability with the use of endorectal balloons in post-prostatectomy radiotherapy

Introduction: We investigated the endorectal balloon (ERB) as a method to improve post-prostatectomy clinical target volume (CTV) stability. Methods: Seventy cone-beam CT (CBCT) obtained during radiotherapy treatment from seven patients treated with an ERB and 68 CBCT from seven patients treated without an ERB were contoured according to published guidelines. CTV was subdivided into superior and inferior CTV; whole rectal volume was subdivided into superior and inferior rectum and anal volume. Concordance index (CI) of CBCT treatment volumes compared with planning volumes was calculated and displacements were measured. Results: Whole rectal, superior and inferior rectum and anal CI were signifi- cantly improved with the ERB by 21%, 17%, 26% and 17% respectively (P \u3c 0.0001). Overall CTV and inferior CTV CI was improved by 4% with the ERB (overall CTV P = 0.021; Inferior CTV P \u3c 0.0001). In the ERB cohort, average displacement for superior CTV was 0.37 cm anterior-posterior (AP) and 0.10 cm left-right (LR). Average standard deviation was 0.27 cm AP and 0.11 cm LR. Inferior CTV average displacement was 0.11 cm AP and 0.02 cm LR. Average standard deviation was 0.11 cm AP and 0.02 cm LR. In the non-ERB cohort, average displacement for superior CTV was 0.43 cm AP and 0.10 mm left-right (LR). Average standard deviation was 0.45 cm AP and 0.13 cm LR. Inferior CTV average displacement was 0.16 cm AP and 0.01 cm LR. Average standard deviation was 0.17 cm AP and 0.03 cm LR. There was no statistically significant impact of bladder filling on CTV CI in ERB patients (P = 0.551) as opposed to non-ERB patients (P = 0.0421). Conclusion: ERBs in the post-prostatectomy setting resulted in increased rectal and CTV stability while negating the effects of bladder filling on CTV stabilit

Endorectal balloons in the post prostatectomy setting: Do gains in stability lead to more predictable dosimetry?

To perform a comparative study assessing potential benefits of endorectal-balloons (ERB) in post-prostatectomy patients. Ten retrospective post-prostatectomy patients treated without ERB and ten prospective patients treated with the ERB in situ were recruited. All patients received IMRT and IGRT using kilovoltage cone-beam computed tomography (kVCBCT). kVCBCT datasets were registered to the planning dataset, recontoured and the original plan recalculated on the kVCBCTs to recreate anatomical conditions during treatment. The imaging, structure and dose data were imported into in-house software for the assessment of geometric variation and cumulative equivalent uniform dose (EUD) in the two groups. The difference in location (DCOV) for the bladder between planning and each CBCT was similar for each group. The use of ERBs in the post-prostatectomy setting did improve geometric reproducibility of the target and surrounding normal tissues, however no improvement in dosimetric stability was observed for the margins employed