Shoalhaven District Memorial Hospital

BACKGROUND AND OBJECTIVE: The aim of the Pulmonary Rehabilitation Guidelines (Guidelines) is to provide evidence-based recommendations for the practice of pulmonary rehabilitation (PR) specific to Australian and New Zealand healthcare contexts. METHODS: The Guideline methodology adhered to the Appraisal of Guidelines for Research and Evaluation (AGREE) II criteria. Nine key questions were constructed in accordance with the PICO (Population, Intervention, Comparator, Outcome) format and reviewed by a COPD consumer group for appropriateness. Systematic reviews were undertaken for each question and recommendations made with the strength of each recommendation based on the GRADE (Gradings of Recommendations, Assessment, Development and Evaluation) criteria. The Guidelines were externally reviewed by a panel of experts. RESULTS: The Guideline panel recommended that patients with mild-to-severe COPD should undergo PR to improve quality of life and exercise capacity and to reduce hospital admissions; that PR could be offered in hospital gyms, community centres or at home and could be provided irrespective of the availability of a structured education programme; that PR should be offered to patients with bronchiectasis, interstitial lung disease and pulmonary hypertension, with the latter in specialized centres. The Guideline panel was unable to make recommendations relating to PR programme length beyond 8 weeks, the optimal model for maintenance after PR, or the use of supplemental oxygen during exercise training. The strength of each recommendation and the quality of the evidence are presented in the summary. CONCLUSION: The Australian and New Zealand Pulmonary Rehabilitation Guidelines present an evaluation of the evidence for nine PICO questions, with recommendations to provide guidance for clinicians and policymakers.

With the recent clinical implementation of real-time MRI-guided x-ray beam therapy (MRXT), attention is turning to the concept of combining real-time MRI guidance with proton beam therapy; MRI-guided proton beam therapy (MRPT). MRI guidance for proton beam therapy is expected to offer a compelling improvement to the current treatment workflow which is warranted arguably more than for x-ray beam therapy. This argument is born out of the fact that proton therapy toxicity outcomes are similar to that of the most advanced IMRT treatments, despite being a fundamentally superior particle for cancer treatment. In this Future of Medical Physics article, we describe the various software and hardware aspects of potential MRPT systems and the corresponding treatment workflow. Significant software developments, particularly focused around adaptive MRI-based planning will be required. The magnetic interaction between the MRI and the proton beamline components will be a key area of focus. For example, the modeling and potential redesign of a magnetically compatible gantry to allow for beam delivery from multiple angles towards a patient located within the bore of an MRI scanner. Further to this, the accuracy of pencil beam scanning and beam monitoring in the presence of an MRI fringe field will require modeling, testing, and potential further development to ensure that the highly targeted radiotherapy is maintained. Looking forward we envisage a clear and accelerated path for hardware development, leveraging from lessons learnt from MRXT development. Within few years, simple prototype systems will likely exist, and in a decade, we could envisage coupled systems with integrated gantries. Such milestones will be key in the development of a more efficient, more accurate, and more successful form of proton beam therapy for many common cancer sites.

PURPOSE: This paper investigates, via magnetic modeling and Monte Carlo simulation, the ability to deliver proton beams to the treatment zone inside a split-bore MRI-guided proton therapy system. METHODS: Field maps from a split-bore 1 T MRI-Linac system are used as input to geant4 Monte Carlo simulations which model the trajectory of proton beams during their paths to the isocenter of the treatment area. Both inline (along the MRI bore) and perpendicular (through the split-bore gap) orientations are simulated. Monoenergetic parallel and diverging beams of energy 90, 195, and 300 MeV starting from 1.5 and 5 m above isocenter are modeled. A phase space file detailing a 2D calibration pattern is used to set the particle starting positions, and their spatial location as they cross isocenter is recorded. No beam scattering, collimation, or modulation of the proton beams is modeled. RESULTS: In the inline orientation, the radial symmetry of the solenoidal style fringe field acts to rotate the protons around the beam's central axis. For protons starting at 1.5 m from isocenter, this rotation is 19° (90 MeV) and 9.8° (300 MeV). A minor focusing toward the beam's central axis is also seen, but only significant, i.e., 2 mm shift at 150 mm off-axis, for 90 MeV protons. For the perpendicular orientation, the main MRI field and near fringe field act as the strongest to deflect the protons in a consistent direction. When starting from 1.5 m above isocenter shifts of 135 mm (90 MeV) and 65 mm (300 MeV) were observed. Further to this, off-axis protons are slightly deflected toward or away from the central axis in the direction perpendicular to the main deflection direction. This leads to a distortion of the phase space pattern, not just a shift. This distortion increases from zero at the central axis to 10 mm (90 MeV) and 5 mm (300 MeV) for a proton 150 mm off-axis. In both orientations, there is a small but subtle difference in the deflection and distortion pattern between protons fired parallel to the beam axis and those fired from a point source. This is indicative of the 3D spatially variant nature of the MRI fringe field. CONCLUSIONS: For the first time, accurate magnetic and Monte Carlo modeling have been used to assess the transport of generic proton beams toward a 1 T split-bore MRI. Significant rotation is observed in the inline orientation, while more complex deflection and distortion are seen in the perpendicular orientation. The results of this study suggest that due to the complexity and energy-dependent nature of the magnetic deflection and distortion, the pencil beam scanning method will be the only choice for delivering a therapeutic proton beam inside a potential MRI-guided proton therapy system in either the inline or perpendicular orientation. Further to this, significant correction strategies will be required to account for the MRI fringe fields.

Assessments of vulnerability to flooding can generate useful data for planners and policy makers. To the best of the authors knowledge, no flood-vulnerability study has combined geophysical modelling of floods with socio-economic assessments of vulnerability at finer municipal or household scale. In addition, the extent to which vulnerability assessments actually feed into flood adaptation policies remains largely unknown. A new flood vulnerability index, and associated methodology, is proposed, combining high-resolution hydrological-hydraulic modelling with built-environment and socio-economic indicators at the smallest spatial scale at which socio-economic data is available. The main advantage of the methodology is its ability to incorporate place-specific data, hence yielding more refined simulations of floods and the capacity to make projections into climate futures at local scale. The index is built and applied to the inter-city suburb of Marrickville in Sydney and used to assess the effects of future climate change on vulnerability mapping in the suburb. Finally, the results of the assessment are presented to, and discussed with, the local government authority responsible for implementing flood adaptation policies for Marrickville. Locally specific modelling of floods, combined with socio-economic and built-environment mapping, has yielded a rich set of information on flood vulnerability and significant variability within a single suburb. Flood duration is projected to increase by more than 100% under some climate change scenarios, as a result of reduced drainage caused by sea level rise. Feedback from municipal council has highlighted the potential usefulness of the knowledge generated by the assessment, especially for emergency services.

Monte Carlo (MC) methods are recognized as the gold-standard for dose calculation, however they have not replaced analytical methods up to now due to their lengthy calculation times. GPU-based applications allow MC dose calculations to be performed on time scales comparable to conventional analytical algorithms. This study focuses on validating our GPU-based MC code for proton dose calculation (gPMC) using an experimentally validated multi-purpose MC code (TOPAS) and compare their performance for clinical patient cases. Clinical cases from five treatment sites were selected covering the full range from very homogeneous patient geometries (liver) to patients with high geometrical complexity (air cavities and density heterogeneities in head-and-neck and lung patients) and from short beam range (breast) to large beam range (prostate). Both gPMC and TOPAS were used to calculate 3D dose distributions for all patients. Comparisons were performed based on target coverage indices (mean dose, V95, D98, D50, D02) and gamma index distributions. Dosimetric indices differed less than 2% between TOPAS and gPMC dose distributions for most cases. Gamma index analysis with 1%/1 mm criterion resulted in a passing rate of more than 94% of all patient voxels receiving more than 10% of the mean target dose, for all patients except for prostate cases. Although clinically insignificant, gPMC resulted in systematic underestimation of target dose for prostate cases by 1-2% compared to TOPAS. Correspondingly the gamma index analysis with 1%/1 mm criterion failed for most beams for this site, while for 2%/1 mm criterion passing rates of more than 94.6% of all patient voxels were observed. For the same initial number of simulated particles, calculation time for a single beam for a typical head and neck patient plan decreased from 4 CPU hours per million particles (2.8-2.9 GHz Intel X5600) for TOPAS to 2.4 s per million particles (NVIDIA TESLA C2075) for gPMC. Excellent agreement was demonstrated between our fast GPU-based MC code (gPMC) and a previously extensively validated multi-purpose MC code (TOPAS) for a comprehensive set of clinical patient cases. This shows that MC dose calculations in proton therapy can be performed on time scales comparable to analytical algorithms with accuracy comparable to state-of-the-art CPU-based MC codes.

Timely recognition and treatment of acutely ill patients at appropriate levels of the health system are fundamental to the quality and safety of healthcare. This study determines if the implementation of an emergency nursing framework HIRAID (History, Identify Red flags, Assessment, Interventions, Diagnostics, communication and reassessment) improves patient safety. A quasi-experimental cohort study was conducted in two emergency departments in [Anonymised], Australia. HIRAID was implemented using a multi-pronged behaviour change intervention. Data of 920 patients (374 pre and 546 post) who deteriorated within 72-hours of ED departure were collected. Statistical tests were conducted as two-sided, with a 95% confidence interval to determine pre/post cohort association. Patients in the post group had more comorbidities, but experienced less deterioration associated with care delivered in the ED (27% to 13%). There was a reduction in treatment delays [ 28.3% to 15.1%, p = 0.041, 95% CI (1.1%–25.3%)], and delay or failure to escalate care when abnormal vital signs were identified [20.2% to6.9%, p = 0.014, 95% CI (3.5%–23.1%)]. Isolated nursing-related causal factors decreased from 20 (21%) to 6 (8%). Implementing a standardised emergency nursing framework is associated with a reduction in clinical deterioration related to emergency care.

Critical wastewater events such as sewer main blockages or overflows are often not detected until after the fact. These events can be costly, from both an environmental impact and monetary standpoint. A standalone, portable radar device allowing non-invasive benchmarking of sewer pumping station (SPS) pumps is presented. Further, by configuring and deploying a complete Low Power Wide Area Network (LPWAN), Shoalhaven Water (SW) now has the opportunity to create "Internet of Things" (IoT)-capable devices that offer freedom from the reliance on mobile network providers, whilst avoiding congestion on the existing Supervisory Control and Data Acquisition (SCADA) telemetry backbone. This network infrastructure allows for devices capable of real-time monitoring to alert of any system failures, providing an effective tool to proactively capture the current state of the sewer network between the much larger SPSs. This paper presents novel solutions to improve the current wastewater network management procedures employed by SW. This paper also offers a complete review of wastewater monitoring networks and is one of the first to offer robust testing of Long Range Wide Area Network (LoRaWAN) network capabilities in Australia. The paper also provides a comprehensive summary of the LoRa protocol and all its functions. It was found that a LPWAN, utilising the LoRaWAN protocol and deployed appropriately within a geographic area, can attain maximum transmission distances of 20 km within an urban environment and up to 35 km line of sight.

OBJECTIVE: To ascertain the use of secondary prevention medications and cardiac rehabilitation after an acute coronary syndrome (ACS) and the impact on 2-year outcomes. METHODS: CONCORDANCE (Cooperative National Registry of Acute Coronary care, Guideline Adherence and Clinical Events) is a prospective, observational registry of 41 Australian hospitals. A representative sample of 6859 patients with an ACS and 6 months' follow-up on 31 May 2016 were included. The main outcome measure was use of ≥75% of indicated medications (≥4/5 (or ≥3/4 if contraindicated) of angiotensin-converting enzyme (ACE) inhibitor/angiotensin receptor blocker, beta-blocker, lipid-lowering therapy, aspirin and other antiplatelet). Major adverse cardiovascular events (MACE) included myocardial infarction, stroke or cardiovascular death. RESULTS: The mean age was 65±13 years, 29% were women, and the mean Global Registry of Acute Coronary Events (GRACE) score was 106±30. At discharge, 92% were on aspirin, 93% lipid-lowering therapy, 78% beta-blocker, 74% ACE/angiotensin receptor blocker and 73% a second antiplatelet; 89% were taking ≥75% of medications at discharge, 78% at 6 months and 66% at 2 years. At 6 months, 38% attended cardiac rehabilitation, 58% received dietary advice and 32% of smokers reported quitting. Among 1896 patients followed to 2 years, death/MACE was less frequent among patients on ≥75% vs <75% of medications (8.3% vs 13.9%; adjusted OR 0.75, 95 % CI 0.56 to 0.99), and was less frequent in patients who attended versus who did not attend cardiac rehabilitation (4.6% vs 13.4%; adjusted OR 0.44, 95% CI 0.31 to 0.62). CONCLUSIONS: Use of secondary prevention therapies diminishes over time following an ACS. Patients receiving secondary prevention had decreased rates of death and MACE at 2 years.

Mass mortalities in flying-foxes occur in summers that reach extremely hot temperatures. In this study, we examine the spatiotemporal distributions of mortality from pup abandonments and extreme heat events in Australian flying-fox camps during the 2019–20 summer. We recorded data on flying-fox mortality in known affected camps and applied a standard method to estimate the number of deaths. Pup mortalities from abandonments were recorded in 10 camps in New South Wales. A minimum estimate of 2612 flying-foxes died in pup abandonments, the majority of which occurred in one camp in Bomaderry. Die-offs from extreme heat events were recorded in 40 camps associated with eight separate heat events in south-eastern Australia. A minimum estimate of 72 175 flying-foxes died during these heat events, which all occurred within the range of the threatened grey-headed flying-fox (Pteropus poliocephalus). Further, 409 and 2251 live flying-foxes were taken into care from pup abandonments and heat events respectively. The minimum mortality estimated represents the highest recorded mortality of Australian flying-foxes within a single summer. This highlights a need to restore vegetation in flying-fox foraging areas and camps, address anthropogenic climate change and gather more empirical data to inform heat stress interventions to minimise flying-fox mortalities.

Flattening filter-free (FFF) beams are becoming the preferred beam type for stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR), as they enable an increase in dose rate and a decrease in treatment time. This work assesses the effects of the flattening filter on small field output factors for 6 MV beams generated by both Elekta and Varian linear accelerators, and determines differences between detector response in flattened (FF) and FFF beams. Relative output factors were measured with a range of detectors (diodes, ionization cham-bers, radiochromic film, and microDiamond) and referenced to the relative output factors measured with an air core fiber optic dosimeter (FOD), a scintillation dosimeter developed at Chris O'Brien Lifehouse, Sydney. Small field correction factors were generated for both FF and FFF beams. Diode measured detector response was compared with a recently published mathematical relation to predict diode response corrections in small fields. The effect of flattening filter removal on detector response was quantified using a ratio of relative detector responses in FFF and FF fields for the same field size. The removal of the flattening filter was found to have a small but measurable effect on ionization chamber response with maximum deviations of less than ± 0.9% across all field sizes measured. Solid-state detectors showed an increased dependence on the flattening filter of up to ± 1.6%. Measured diode response was within ± 1.1% of the published mathematical relation for all fields up to 30 mm, independent of linac type and presence or absence of a flattening filter. For 6 MV beams, detector correction factors between FFF and FF beams are interchangeable for a linac between FF and FFF modes, providing that an additional uncertainty of up to ± 1.6% is accepted.

Grazing of livestock on pasture land can result in changes to the physical condition of soil, particularly as a result of trampling and changed organic matter status of the topsoil. Over time, changes to pasture botanical composition may also occur, which might further affect soil structure. The extent of the effects, and the rate of soil and pasture recovery when livestock are removed, will depend on the grazing management tactics employed. A field study was established at Orange, New South Wales, to compare soil physical properties under ‘set-stocked’ grazing of Merino sheep, ‘high intensity–short duration’ rotational grazing, an ungrazed control, and pasture cages. Topsoil bulk density, hydraulic conductivity, and organic carbon content were measured annually over 3 years, and image analysis of soil macroporosity was carried out annually to quantify changes in pore geometry. Only the topsoil macropore properties changed significantly between treatments over the 3 years. In particular, the structural quality of the topsoil under set-stocked grazing changed, as indicated by a decrease in total macroporosity and a smaller proportion of macropores. In contrast, stable structural conditions were maintained under rotational grazing. Possibly the best soil structure for plant growth, represented by high values of total macroporosity and macropore surface area, and a large range of pore sizes, was exhibited under the pasture cages, where pasture defoliation occurred in the absence of hoof pressure. It is concluded that grazing tactics are an important factor in the dynamics of soil macroporosity and the vertical continuity of macropores, as a result of the combined effects of hoof pressure and root channel development.

BACKGROUND: Quality of life may be negatively impacted following cataract surgery if glasses prescription is delayed. This study aims to confirm the refractive stabilisation time in an Australian population to form the basis for suggesting an appropriate timeframe for spectacle prescription. METHODS: Participants (51 female and 35 male) were recruited one day after uncomplicated unilateral cataract surgery using a monofocal intraocular lens. Subjective refraction, automated refraction and central corneal thickness were measured at two, four and six weeks post-operatively. A short questionnaire assessing the impact of uncorrected near vision on daily activities was collected at two and four weeks. RESULTS: < 0.001) over the six-week study period. At week two, 59 per cent of patients stated that their uncorrected near vision affected their ability to perform daily tasks 'somewhat' or 'a lot', increasing to 75 per cent by week four. CONCLUSION: Uncorrected near vision affected quality of life for most participants. All measured visual and ocular parameters were stable from two weeks post-operatively. Patients need not wait longer than this for spectacle prescription following uncomplicated unilateral cataract surgery.

This study quantified the interplay and gradient effects on GTV dose coverage for 3D CRT, dMLC IMRT, and VMAT SABR treatments for target amplitudes of 5-30 mm using 3DVH v3.1 software incorporating 4D Respiratory MotionSim (4D RMS) module. For clinically relevant motion periods (5 s), the interplay effect was small, with deviations in the minimum dose covering the target volume (D99%) of less than ± 2.5% for target amplitudes up to 30 mm. Increasing the period to 60 s resulted in interplay effects of up to ± 15.0% on target D99% dose coverage. The gradient effect introduced by target motion resulted in deviations of up to ± 3.5% in D99% target dose coverage. VMAT treatments showed the largest deviation in dose metrics, which was attributed to the long delivery times in comparison to dMLC IMRT. Retrospective patient analysis indicated minimal interplay and gradient effects for patients treated with dMLC IMRT at the NCCI.

Low energy availability (LEA) is considered to be the underlying cause of a number of maladaptations in athletes, including impaired physiological function, low bone mineral density (BMD), and hormonal dysfunction. This is collectively referred to as 'Relative Energy Deficiency in Sport' (RED-S). LEA is calculated through assessment of dietary energy intake (EI), exercise energy expenditure (EEE) and fat-free mass (FFM). The incidence of LEA in Paralympic athletes is relatively unknown; however, there are legitimate concerns that Para athletes may be at even higher risk of LEA than able-bodied athletes. Unfortunately, there are numerous issues with the application of LEA assessment tools and the criterion for diagnosis within the context of a Para population. The calculation of EEE, in particular, is limited by a distinct lack of published data that cover a range of impairments and activities. In addition, for several RED-S-related factors, it is difficult to distinguish whether they are truly related to LEA or a consequence of the athlete's impairment and medical history. This narrative review outlines deficits and complexities when assessing RED-S and LEA in Para athletes, presents the information that we do have, and provides suggestions for future progress in this important area of sports nutrition.

BACKGROUND: This study evaluated the safety, efficacy and compliance of an emerging technique for managing complex subcutaneous abscesses in an adult population (≥16 years). METHODS: A retrospective review of prospectively collected data between April and October 2015 at a rural hospital comparing conventional incision drainage (CID) and repetitive packing to the minimal incision, irrigation, loop and drain technique (LDT). LDT method was consistent with previous publications, being ≤5 mm incisions at abscess edges, irrigation and passage of a VessiLoop through the cavity and then secured above the skin. The loop remained in situ until resolution. Both groups had empirical oral antibiotics. RESULTS: Sixty-three patients required intervention for complex subcutaneous abscess: CID group had 27 patients and LDT had 36 patients. The mean age of CID group was 43.9 years (range: 16-86 years), all required intervention in theatre with 10 patients lost to follow-up (37%) and the remaining 17 required a mean of 11.8 (range: 1-17) care visits. The mean age of LDT group was 34.9 years (range: 16-62 years), 11 completed intervention in ED under local anaesthetic (30%) and 27 required general anaesthesia. Compliance to follow-up clinic was 100%: 27 seen once at 10-14 days with loop removal and nine were seen a second time to complete care. There were no re-operations. CONCLUSION: This is the first LDT data in adults and proves it is safe and effective. It saves operating theatre time with 30% of LDT treated in the Emergency Department and ensures excellent follow-up compliance as patients return for VessiLoop removal. Healthcare burden is greatly reduced using LDT; most patients require only one review at 10-14 days.

Abstract Occupational potential, which is defined as human capacity to engage in meaningful occupations, is proposed as a worthy focus for occupational science research. Derived from research with older women living in a rural Australian town, the notion of occupational potential is described as a concept with historic roots dating back to Aristotle and in biblical references. It is also evident in the Utopian communities of the 16th‐18th centuries. The article proposes that occupational potential is a concept that complements notions of occupational identity and occupational justice. It further proposes that it will have practical application in working with people whose access to occupation is disrupted by civil unrest and war, and those who are subject to oppressive political regimes.

BACKGROUND: Anemia commonly accompanies acute coronary syndromes (ACS) and is associated with poorer outcomes. This study examines the associations between anemia, management and outcomes in an Australian ACS population. METHODS: This analysis of the CONCORDANCE database included 8665 ACS patients presenting to 41 Australian hospitals. Baseline characteristics, management, and outcomes were compared between patients with anemia (Hb ≤ 130 for males, Hb ≤ 120 g/L for females) and non-anemia. RESULTS: A total of 1880 (21.7%) patients presenting with ACS were anemic. These patients were older (72 years vs 63 years, P < .0001), with higher prevalence of comorbidities. STEMI patients with anemia were less likely to be emergently reperfused with either thrombolytic therapy (22% vs 33%, P < .0001) or primary percutaneous coronary intervention (PCI) (45% vs 51% P = 0.033). For all ACS, anemic patients less frequently received: coronary angiography (63% vs 86%, P < .0001); drug eluting stents if undergoing PCI (50% vs 58%, P < .0001); dual antiplatelet therapy (80% vs 89%, P < .0001) ;and parenteral anticoagulants (82% vs 88%, P < .0001). In hospital complications of heart failure (20% vs 9%, P < .0001), renal failure (13% vs 4%, P < .0001), and re-infarction (4% vs 2%, P = .0006) were more common among anemic patients. There was a near-linear inverse relationship between admission hemoglobin and in hospital mortality. CONCLUSIONS: Anemic patients with ACS are a high risk group less likely to undergo invasive and antithrombotic therapy. Further investigation is required to determine if more active treatment of anemic patients presenting with ACS will improve their outcomes.

BACKGROUND: The role of routine intraoperative cholangiograms (IOCs) for prevention of bile duct injury (BDI) is contentious. There are recent reports of limited utility of IOC in preventing BDI. In Australia, IOCs are used more frequently than internationally. This study aimed to evaluate the rate of IOC use in Australia and explore potential changes in practice in light of evolving evidence for the utility of IOC. METHODS: Data were collated using service item numbers in Medicare Benefits Scheme records on the Australian Government Medicare website, for services claimed between 1 January 2001 and 31 December 2019. These data were used to analyse trends in rates of IOC, cholecystectomy and BDI repair. Data were age-standardized to account for changes in the population over time. RESULTS: The number of IOCs claimed increased by 31.8% and cholecystectomies by 7.0% over the study period. Age-standardized service rates per 100 000 persons increased by 5.5 and 32.6, respectively. Rates of IOC per 100 000 cholecystectomies steadily increased across the study period, while BDI repair rates remained low and erratic. CONCLUSION: Increasing use of IOC over the last 20 years reflects a trend towards routine rather than selective IOC; however, there is little discernible change in the number of BDIs requiring repair procedures. This suggests that routine IOC use to prevent or minimize BDI is unwarranted. Further investigation is required into the selective IOC use in high-risk patients rather than mandatory use in all patients.

BACKGROUND: The impact of increased body mass index (BMI) on clinical outcomes in locoregional rectal cancer is unknown. METHODS: This is a retrospective cohort study which included 453 consecutive rectal cancer patients undergoing definitive treatment, with confirmed stage I, II or III rectal adenocarcinoma. The association of BMI at diagnosis with overall survival (OS), cancer specific survival (CSS) and disease-free survival (DFS) was explored, controlling for key covariates using multivariable analyses. BMI as defined by the World Health Organization (WHO) is as follows: BMI <18.5-underweight; 18.5-24.9-normal; 25.0-29.9-pre-obesity; >30-obese. RESULTS: Overweight and obese patients had significantly better OS than underweight/normal weight patients (5-year OS 80% for overweight, 77% for obese, and 65% for underweight/normal weight patients, P=0.02). High BMI (>25) was significantly associated with improved OS in univariate [0.62 (0.4-0.8) P=0.007] and multivariable [0.65 (0.4-0.9) P=0.023] analyses. When stratified by stage, high BMI was associated with improved OS in stage III patients (P=0.0009), but not stage II (P=0.21) or stage I (0.54). High BMI was also significantly associated with improved CSS in univariate (HR 0.62, P=0.048) and multivariable analyses (HR 0.58, P=0.03). CONCLUSIONS: In our study a BMI greater than 25 is significantly associated with a longer OS and CSS in patients with locoregional rectal cancer. These findings may be due to the reduced metabolic capacity for non-obese patients to deal with rectal cancer treatment as well as the burden of disease, however further research is needed to evaluate this.

for 50 cm FSD. Substantial polarity effects, up to 9.6%, were observed for the Advanced Markus chamber compared to a maximum 0.5% for the Roos chamber. The magnitude of the polarity effect was observed to increase with field size and beam energy but was consistent with depth. The polarity effect is directly influenced by chamber design, with potentially large polarity effects for some plane-parallel ionisation chambers. Depending on the specific chamber used, polarity corrections may be required for output factor measurements of kilovoltage photon beams. Failure to account for polarity effects could lead to an incorrect dose being delivered to the patient.