Improvement in male pelvis magnetic resonance image contouring following radiologist-delivered training.

INTRODUCTION: The magnetic resonance linear accelerator (MRL) combines both magnetic resonance imaging and a linear accelerator, allowing for daily treatment adaptation. This study aimed to assess the impact of radiologist-delivered training in magnetic resonance (MR) contouring of relevant structures within the male pelvis. METHODS: Two radiation oncologists, two radiation oncology registrars and seven radiation therapists completed contouring on 10 male pelvis MR datasets both pre- and post-training. A 2-hour MR anatomy training session was delivered by a radiologist, who also provided the 'gold standard' contours. The pre- and post-training contours were compared against the gold standard with Dice similarity coefficient (DSC) and Hausdorff distances calculated; and the pre- and post-confidence scores and timing were compared. RESULTS: The improvement in DSC were significant in prostate, rectum and seminal vesicles, with a post-training median DSC of 0.87 ± 0.06, 0.92 ± 0.04 and 0.80 ± 0.14, respectively. The median Hausdorff improved with a median of 1.46 ± 0.78 mm, 0.52 ± 0.32 mm and 1.11 ± 0.86 mm for prostate, rectum and seminal vesicles, respectively. Bladder concordance was high both pre- and post-training. Urethra contours improved post-training, however, remained difficult to contour with a median post-DSC of 0.51 ± 0.24. Overall, confidence scoring improved (P < 0.001) and timing decreased by an average of 4.4 ± 16.4 min post-training. CONCLUSION: Radiologist-delivered training improved concordance of male pelvis contouring on MR datasets. Further work is required in the identification of urethra on MRs. These findings are of importance in the MRL adaptive workflow.

The Modernization of Radiation Therapy Services in Cambodia: A Model of International Collaboration.

PURPOSE: Cambodia is a Southeast Asian low-middle-income country with a population of >15 million. In 2020, Cambodia was estimated to have 18,375 new diagnoses of cancer and 12,638 deaths attributable to cancer. Cambodia was estimated to have a deficit of 16 megavoltage machines in 2012. Cambodia's radiation therapy services have suffered through the tumultuous events of the country's history, with intermittent services until the last decade. In recent years, Cambodia has undergone rapid economic growth and, with this, the development of its first comprehensive cancer center, the National Cancer Centre (NCC). METHODS AND MATERIALS: Planning for NCC began in the early 2000s, with the aim to provide comprehensive care, including modern radiation therapy services, to the public. Funding for the center was supplied primarily by the Cambodian government, assisted by donations from partners including the International Atomic Energy Agency. Training collaborations were formed with international partners, including the Asia-Pacific Radiation Oncology Special Interest Group (APROSIG) of the Royal Australian and New Zealand College of Radiologists and the Asia-Pacific Special Interest Group (APSIG) of the Australasian College of Physical Scientists and Engineers in Medicine. RESULTS: The main model of APROSIG/APSIG collaboration has been in-country training, including the posting of an Australian medical physicist and radiation therapist in Phnom Penh for a year's duration to oversee a safe and sustainable start to the radiation therapy program. The first linear accelerator patient was treated at NCC in March 2018 and the first brachytherapy patient in September 2018. Since that time, the department has treated to capacity, with very little machine downtime. NCC provides comprehensive cancer services including medical oncology, pediatric oncology, hematology, palliative care, surgical oncology, and nuclear medicine. Several challenges to expanding radiation therapy services currently exist, including human resources and cultural stigma. CONCLUSION: Despite many decades of tragedy and suffering, Cambodia serves as an example of successful implementation of modern radiation therapy in a low- and middle-income country. The keys to success have included local champions, support of the Ministry of Health, and willingness to embrace collaboration. The pandemic brings yet another challenge to cancer control in Cambodia, and novel training platforms are being explored.

Sources of out-of-field dose in MRgRT: an inter-comparison of measured and Monaco treatment planning system doses for the Elekta Unity MR-linac.

With the clinical introduction of MR-linacs, out-of-field dose (OFD) associated with head leakage/scatter (HLS), spiralling contaminant electrons (SCE) and the electron streaming effect (ESE) is of interest. To investigate HLS and SCE, EBT3 film on solid water 5.0 cm beyond each edge of a 10.0 × 10.0 cm2 field was used to determine depth-dose for 0 T and 1.5 T, in the isocentric plane. Additionally, ESE induced by the anterior imaging coil was quantified and the experimental arrangements to measure SCE and ESE were modelled using Monaco. For a clinical treatment of supraclavicular nodal disease, Monaco OFD was compared to in vivo measurements. For 0 T, depth-dose was isotropic and surface dose was approximately 4.4% of Dmax. With 1.5 T surface doses were approximately 3.8% of Dmax at ± Y (IEC61217), compared to 2.6% and 0.6% of Dmax at - X and X, respectively. For both field strengths, the TPS depth-dose variation was consistent with experimental trends; however, near surface doses calculated at ± Y differed significantly from measurements. For the field sizes investigated, measured coil ESE dose was between 9.0 and 28.0% of Dmax and Monaco coil ESE was less than measured by up to 13.0%. OFD in 0 T and 1.5 T are comparable at ± Y, inconsistent with previous work. Anterior coil ESE should be mitigated during treatment and for the clinical case investigated, in vivo OFD was within 2σ of TPS calculations. Monaco overestimates near surface SCE and underestimates coil ESE.

Physical therapy services utilization and length of stay for obese patients following traumatic leg fracture.

BACKGROUND: Obesity is an increasing epidemic that can complicate the treatment of simple injuries and can increase health care costs. The purpose of the present study was to determine whether obesity is a factor in the utilization of inpatient physical therapy services and length of stay following a traumatic lower leg fracture. METHODS: A retrospective study of patients admitted to the hospital in 2005 and 2006 with a primary discharge diagnosis of lower leg or ankle fracture was conducted. Inclusion criteria were age > or = 18 years, only 1 involved lower extremity, and nonweight-bearing on the affected extremity per physician orders. Patients were excluded from the study if they had a fibular fracture only, pathological fractures, multiple trauma, severe cardiac or vascular comorbidities, or cognitive impairments. Data were compiled into 3 categories on the basis of body mass index (BMI): < 30, 30-35, > 35. Physical therapy services were measured in 15-minute units of time. These data were analyzed by within-group and between-group comparisons and with regression analysis. RESULTS: A total of 181 patients with a primary discharge diagnosis of distal lower extremity or ankle fracture were included in the study. Patients with a BMI >35 used more physical therapy services (mean services, 9.8 units) than did patients with a BMI of 30-35 (mean services, 6.2 units) or a BMI <30 (mean services, 5.6 units) (P = .001). Length of stay was also highest among patients with a BMI >35. LIMITATIONS: Factors other than BMI may be associated with length of stay and physical therapy use and may confound the association. CONCLUSION: Previous studies have shown that there is an increase in health care utilization among the bariatric population. The present study demonstrates similar findings for physical therapy services. Increased length of stay and physical therapy utilization among the bariatric population also result in increased staff utilization and equipment costs.