Improving plan quality in cervical brachytherapy using a simple knowledge-based prediction tool for OAR dose (D2cm3).

PURPOSE: Toxicity from cervical brachytherapy has been demonstrated to correlate with the D2cm3 of the bladder, rectum, and bowel. This suggests a simplified version of knowledge-based planning investigating the relationship of the overlap distance for 2cm3 and the D2cm3 from planning may be possible. This work demonstrates the feasibility of simple knowledge-based planning to predict the D2cm3, detect suboptimal plans, and improve plan quality. METHODS AND MATERIALS: The overlap volume histogram (OVH) method was used to determine the distance for 2cm3 of overlap between the OAR and CTV_HR. Linear plots modeled the OAR D2cm3 and 2cm3 overlap distance. Two datasets of 20 patients (plans from 43 insertions in each dataset) were used to create two independent models, and the performance of each model was compared using cross-validation. Doses were scaled to ensure consistent CTV_HR D90 values. The predicted D2cm3 is entered as the maximum constraint in the inverse planning algorithm. RESULTS: Mean bladder D2cm3 decreased by 2.9% for the models from each dataset, mean rectal D2cm3 decreased 14.9% for the model from dataset 1 and 6.0% for the model from dataset 2, mean sigmoid D2cm3 decreased 10.7% for the model from dataset 1 and 6.1% for the model from dataset 2, mean bowel D2cm3 decreased 4.1% for the model from dataset 1 but no statistically significant difference was observed for the model from dataset 2. CONCLUSIONS: A simplified knowledge-based planning method was used to predict D2cm3 and was able to automate optimization of brachytherapy plans for locally advanced cervical cancer.

How Tourist Preference and Satisfaction Can Contribute to Improved Welfare Standards at Elephant Tourism Venues in Thailand.

Consumer satisfaction and preference can be integral in influencing and solidifying change in user-driven industries such as tourism. High satisfaction rates are imperative to the continual success of a venue as satisfaction determines the likelihood of repeat business and positive recommendations to friends, family and online review forums. Tourist preference for ecocentric tourism venues, over anthropocentric ones, appears to be increasing in elephant tourism venues (ETVs) in Thailand. To explore this, we visited twelve ETVs in Chiang Mai, Thailand, and compared the preferences and satisfaction of tourists who visited riding and non-riding venues toward the use of captive elephants in an entertainment setting. We found that tourists visited riding and non-riding ETVs for similar reasons, primarily due to recommendations from friends and reviews, and because the venue had a good reputation. Tourist preference for higher welfare standards was observed at venues where participants directly observed poor treatment of the elephants. Tourist satisfaction may be impacted by higher elephant welfare standards; therefore, tourists have the ability to influence the elephant tourism industry by demanding better living conditions for elephants and only financially supporting ETVs with higher welfare standards.

A single-institution review of image-guided brachytherapy for vaginal malignancies using customized molded applicators and interstitial needles.

PURPOSE: To review a single-institution's pattern of practice, dosimetry results, and clinical outcomes for patients with unresectable malignancies of vagina, vulva, or urethra, receiving brachytherapy using customized vaginal moulds with or without interstitial needles. MATERIAL AND METHODS: Twenty-one consecutive patients were reviewed. Patients were treated using customized moulds with or without interstitial needles, implanted with a free-hand technique. Technical implementation, such as type of implant and imaging used were recorded. D90 and D98 of clinical target volume (CTV), D0.1cc of urethra, and D2cc and D0.1cc of bladder and rectum were analyzed. Any adverse clinical outcomes were reported. RESULTS: Eleven patients experienced endometrial cancer recurrences, one a cervical cancer recurrence and nine vaginal or peri-urethral primary disease. After a median follow-up of 3.5 years, local control was achieved in 14 patients (67%). Median D98 and D90 to CTV was 73.7 Gy and 78.3 Gy, respectively. One patient died from disease progression, one developed distant metastasis, and seven failed locally. Median D2cc to bladder was 64.8 Gy, with low-grade toxicity reported. Median D2cc to rectum was 62.9 Gy, with low-grade toxicity and one case of rectal proctitis was observed. Median urethral D0.1cc was 66 Gy, with no toxicity reported. One patient suffered from a sacral insufficiency fracture. It was presumed that vaginal mucosa proximal to CTV received the total dose, with two patients developing vaginal ulcers, which both resolved; 10 patients reported mild telangiectasia, fibrosis, or stenosis. CONCLUSIONS: A review of patients treated with a customized vaginal mould and interstitial needles showed acceptable doses to CTV, with local control achieved in 67% of patients, and reasonable doses to organs at risk (OARs) and acceptable toxicity.

Pediatric peri-operative fractionated high-dose-rate brachytherapy for recurrent Wilms' tumor using a reconstructed Freiburg flap.

PURPOSE: To report peri-operative fractionated high-dose-rate (HDR) brachytherapy with a 3D customized Freiburg flap applicator to treat locally recurrent Wilms' tumor, followed by immediate hyperthermic intraperitoneal chemotherapy for a 16-year-old with a second recurrence of nephroblastoma (Wilms' tumor). MATERIAL AND METHODS: The tumor was excised and surgical bed was treated with fractionated HDR brachytherapy using a Freiburg flap applicator. Hyperthermic intraperitoneal chemotherapy was performed immediately after the removal of brachytherapy applicator. RESULTS: The Freiburg flap was successfully reconstructed to enable delivery of conformable peri-operative HDR brachytherapy. The clinical target volume (CTV) D90 was 26 Gy in 5 fractions. CONCLUSIONS: Peri-operative fractionated HDR brachytherapy with a customized Freiburg flap applicator was delivered successfully across a large multi-disciplinary team.

Can Citizen Science Assist in Determining Koala (Phascolarctos cinereus) Presence in a Declining Population?

The acceptance and application of citizen science has risen over the last 10 years, with this rise likely attributed to an increase in public awareness surrounding anthropogenic impacts affecting urban ecosystems. Citizen science projects have the potential to expand upon data collected by specialist researchers as they are able to gain access to previously unattainable information, consequently increasing the likelihood of an effective management program. The primary objective of this research was to develop guidelines for a successful regional-scale citizen science project following a critical analysis of 12 existing citizen science case studies. Secondly, the effectiveness of these guidelines was measured through the implementation of a citizen science project, Koala Quest, for the purpose of estimating the presence of koalas in a fragmented landscape. Consequently, this research aimed to determine whether citizen-collected data can augment traditional science research methods, by comparing and contrasting the abundance of koala sightings gathered by citizen scientists and professional researchers. Based upon the guidelines developed, Koala Quest methodologies were designed, the study conducted, and the efficacy of the project assessed. To combat the high variability of estimated koala populations due to differences in counting techniques, a national monitoring and evaluation program is required, in addition to a standardised method for conducting koala population estimates. Citizen science is a useful method for monitoring animals such as the koala, which are sparsely distributed throughout a vast geographical area, as the large numbers of volunteers recruited by a citizen science project are capable of monitoring a similarly broad spatial range.

Experimental validation of the dual parameter beam quality specifier for reference dosimetry in flattening-filter-free (FFF) photon beams.

Removal of the flattening filter alters the energy spectrum of the photon beam such that current beam quality specifiers may not correctly account for this change when predicting the Spencer-Attix restricted water-to-air mass collision stopping-power ratio, (L/ρ)(water)(air). Johnsson et al (2000 Phys. Med. Biol. 45 2733-45) proposed a beam quality specifier, known as the dual parameter beam quality specifier, which was calculated via Monte Carlo (MC) simulations using transmission data of primary kerma through two differing thicknesses of water material. Ceberg et al (2010 Med. Phys. 37 1164-8) extended this MC study to include relevant flattening filter free (FFF) beam data. Experimental investigations of this dual parameter beam quality specifier have not previously been published, therefore the purpose of this work was to validate that the dual parameter beam quality specifier could be measured experimentally for clinical beams (both with a flattening filter (WFF) and without (FFF)). Transmission measurements of primary kerma were performed by employing the setup outlined in Johnsson et al (1999 Phys. Med. Biol. 44 2445-50). Varying absorber thicknesses, in 5 cm increments from 5 to 40 cm, were placed at isocentre with the chamber positioned at an extended source to chamber distance of 300 cm. Experimental setup for TPR20,10 and %dd(10)x followed the methodology outlined in IAEA TRS398 (2004) and TG-51 (1999) with AAPM Addendum to TG-51 (2014) respectively. The maximum difference of (L/ρ)(water)(air) determined using the different beam quality specifiers was found to be 0.35%. Analysis of the absorber thickness combination found that small thicknesses (<10 cm) for the first absorber and absorbers similar in thickness (<10 cm) should be avoided. Stopping-power ratios of the beams investigated were determined using three different beam quality specifiers. The results demonstrated successful experimental determination of the dual parameter beam quality specifier, indicating its potential as an alternate beam quality specifier for FFF beams.