The distribution of subarctic and boreal deep-sea demersal fish assemblages across environmental gradients of the northwest Atlantic.

The oceanography of the Labrador Sea is well studied because of its globally important deep-water convection that oxygenates the deep ocean and drives climate-regulating ocean currents. However, little is known about the fish communities that inhabit this area, particularly beyond the depths accessible to standard research surveys and commercial fishing activities. We used baited longline surveys to characterize important components of demersal fish communities across a depth gradient of 200-3000 m and compared these data to a similar dataset collected c. 1200 km to the south in the Flemish Cap Region. We found demersal fish communities in the Labrador Sea to be similar to those of the Flemish Cap Region despite unique oceanography and lower primary productivity in the Labrador Sea. Moreover, both areas had high abundance, biomass, and species richness at intermediate depths that suggests factors beyond depth drive community structure in the deep ocean. These data are important for identifying high-value areas for potential protective measures in the northwest Atlantic and provide necessary data with which to assess potential environmental impacts of extractive industries that are expanding north and to deeper waters.

Improving UV Curing in Organosolv Lignin-Containing Photopolymers for Stereolithography by Reduction and Acylation.

Despite recent successes in incorporating lignin into photoactive resins, lignin photo-properties can be detrimental to its application in UV-curable photopolymers, especially in specialized engineered resins for use in stereolithography printing. We report on chemical modification techniques employed to reduce UV absorption by lignin and the resulting mechanical, thermal, and cure properties of these modified lignin materials. Lignin was modified using reduction and acylation reactions and incorporated into a 3D printable resin formulation. UV-Vis absorption at the 3D printing range of 405 nm was reduced in all modified lignins compared to the unmodified sample by 25% to ≥ 60%. Resins made with the modified lignins showed an increase in stiffness and strength with lower thermal stability. Studying these techniques is an important step in developing lignin for use in UV-curing applications and further the effort to valorize lignin towards commercial use.

Optimization of autogenerated chest-wall radiation treatment plans developed for postmastectomy breast cancer patients in underserved clinics.

Over the past decade, several strides have been made to improve the management of breast cancer in developing countries; however, there are still obstacles present. In the area of radiation therapy, these hurdles include limited access to radiotherapy treatment and scarcity of oncology specialists. In an effort to reduce inequities in cancer care while improving patient outcomes, our research is focused on developing automated postmastectomy radiation therapy (PMRT) plans for breast cancer patients in these underserved communities that can be further improved upon through treatment planning system (TPS) specific optimization guidelines. The automated planning tool utilized algorithms integrated with Varian's Eclipse TPS. The tool created PMRT plans that used monoisocentric tangents and supraclavicular (SCV) fields with a mix of high and low energy photon beams along with field-in-field (FIF) segments. The completed autogenerated PMRT plans were imported into Phillip's Pinnacle 9.10 and Varian's Eclipse 13.6 TPSs to be further improved through manual optimization; the time required to complete this step was measured and assessed. A senior dosimetrist, physicist, and physician evaluated the optimized plans for clinical acceptability. Guidelines were developed for the planning systems that can be implemented by personnel with either limited experience in radiation treatment planning or those with limited time to produce treatment plans. The autogenerated plans in conjunction with our guidelines have shown to significantly reduce the time required to produce a clinically acceptable PMRT plan from approximately 120 ± 60 minutes to just 13 ± 11 (Pinnacle) and 12 ± 7 (Eclipse) minutes, reducing the total uninterrupted treatment planning time by an average of 108 ± 51 minutes. The results from this research indicate that the autogenerated PMRT plans along with the optimization guidelines are a viable option to provide quality and clinically acceptable PMRT plans that are more efficient and consistent for postmastectomy breast cancer patients in severely underserved communities.

Lignin-Containing Photoactive Resins for 3D Printing by Stereolithography.

Generating compatible and competitive materials that are environmentally sustainable and economically viable is paramount for the success of additive manufacturing using renewable materials. We report the successful application of renewable, modified lignin-containing photopolymer resins in a commercial stereolithography system. Resins were fabricated within operable ranges for viscosity and cure properties, using up to 15% modified lignin by weight. A 4-fold increase in ductility in cured parts with higher lignin concentration is noted compared to commercial stereolithography resins. Excellent print quality was seen in modified lignin resins, with good layer fusion, high surface definition, and visual clarity. These materials can be used to generate new products for additive manufacturing applications and help fill vacant material property spaces, where ductility, sustainability, and application costs are critical.

Incidence and predictors of chest wall toxicity after high-dose radiation therapy in 15 fractions.

PURPOSE: Fifteen fraction treatment schedules are increasingly used to deliver high doses of radiation therapy (RT) to both lung and hepatobiliary malignancies. The purpose of our study was to examine the incidence and predictors of chest wall (CW) toxicity in patients treated with this regimen. METHODS AND MATERIALS: We evaluated 135 patients treated with RT to doses ≥52.5 Gy in 15 fractions for thoracic and hepatobiliary malignancies between January 2009 and December 2012. We documented patient characteristics and CW dosimetric parameters for each case. Toxicity was scored using the Common Terminology Criteria for Adverse Events, version 4.0, criteria for radiation dermatitis and CW pain. Patient characteristics and CW dosimetric parameters were evaluated for their association with CW toxicity using proportional hazards regression. RESULTS: Median follow-up was 9 months from the start of RT. Forty-eight patients (36%) developed dermatitis at a median time of 18 days. In multivariable analysis, the absolute volume of CW (in cm3) receiving 40 Gy (V40) ≥120 cm3 was associated with the occurrence of dermatitis (hazard ratio, 3.12; 95% confidence interval, 1.74-5.60; P < .001). Twenty-one patients (16%) developed CW pain (20 grade 1, 1 grade 2) at a median time of 3 months. In multivariable analysis, CW V40 ≥150 cm3 was associated with the occurrence of CW pain (hazard ratio, 2.65; 95% confidence interval, 1.12-6.24; P = .03). The absolute rate of CW pain in patients with V40 <150 cm3 was 11% versus 26% in patients with V40 ≥150 cm3 (P = .03). CONCLUSIONS: Hypofractionated RT with 15 fraction regimens results in an acceptable incidence of CW toxicity, specifically CW pain. We recommend a dose constraint of V40 <150 cm3 to minimize this adverse event.

Early experience with intensity modulated proton therapy for lung-intact mesothelioma: A case series.

PURPOSE: The purpose of this study was to describe our experience implementing intensity modulated proton therapy (IMPT) for lung-intact malignant pleural mesothelioma (MPM), including patient selection, treatment planning, dose verification, and process optimization. METHODS AND MATERIALS: Seven patients with epithelioid MPM were reviewed; 6 underwent pleurectomy, whereas 1 had biopsy alone. Four patients received IMPT and 3 received intensity modulated radiation therapy. Treatment plans for the other modality were created for dosimetric comparisons. Quality assurance processes included dose verification and robustness analysis. Image-guided setup was performed with the first isocenter, and couch shifts were applied to reposition to the second isocenter. RESULTS: Treatment with IMPT was well tolerated and completed without breaks. IMPT plans were designed with 2 isocenters, 4 beams, and ≤64 energy layers per beam. Dose verification processes were completed in 3 hours. Total daily treatment time was approximately 45 minutes (20 minutes for setup and 25 minutes for delivery). IMPT produced lower mean doses to the contralateral lung, heart, esophagus, liver, and ipsilateral kidney, with increased contralateral lung sparing when mediastinal boost was required for nodal disease. CONCLUSIONS: Our initial experience showed that IMPT was feasible for routine care of patients with lung-intact MPM.

Use of simultaneous radiation boost achieves high control rates in patients with non-small-cell lung cancer who are not candidates for surgery or conventional chemoradiation.

BACKGROUND: Intensity-modulated radiation therapy (IMRT) with a simultaneous integrated boost (SIB) has improved the local disease control at a variety of anatomic sites. However, little is known about its use in lung cancer, especially in the context of shorter treatment schedules (hypofractionation). We analyzed the feasibility, toxicity, and patterns of failure of this approach for patients with non-small-cell lung cancer (NSCLC) who were not candidates for surgery or standard concurrent chemoradiation therapy. PATIENTS AND METHODS: We retrospectively identified 71 patients with NSCLC who received IMRT+SIB in 15 fractions to ≥ 52.5 Gy from January 2007 to February 2013. Toxicity and local control were evaluated for all patients. RESULTS: Of the 71 patients, 11 (16%) had stage I to II NSCLC, 15 (21%) stage III, and 45 (63%) stage IV. The esophagitis rate was grade 0 to 1 in 55%, grade 2 in 39%, and grade ≥ 3 in 6%. One patient developed a bronchoesophageal fistula 6 months after radiation. The pneumonitis rate was grade 0 to 1 in 93%, grade 2 in 6%, and grade 3 in 1%. At the time of analysis, 17 (24%) patients had local failure at a median of 5.2 months (range, < 1-16.1) after treatment. All but 1 failure occurred within the higher dose region. CONCLUSION: Hypofractionated IMRT+SIB is a viable option for some patients with NSCLC, with little high-grade toxicity overall. Nearly all local failures occurred within the higher dose region, implying strong radioresistance or some other mechanism for recurrence in a subgroup of patients.

A dosimetric comparative study: volumetric modulated arc therapy vs intensity-modulated radiation therapy in the treatment of nasal cavity carcinomas.

The purpose of this study was to evaluate the differences between volumetric modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) in the treatment of nasal cavity carcinomas. The treatment of 10 patients, who had completed IMRT treatment for resected tumors of the nasal cavity, was replanned with the Philips Pinnacle(3) Version 9 treatment-planning system. The IMRT plans used a 9-beam technique whereas the VMAT (known as SmartArc) plans used a 3-arc technique. Both types of plans were optimized using Philips Pinnacle(3) Direct Machine Parameter Optimization algorithm. IMRT and VMAT plans' quality was compared by evaluating the maximum, minimum, and mean doses to the target volumes and organs at risk, monitor units (MUs), and the treatment delivery time. Our results indicate that VMAT is capable of greatly reducing treatment delivery time and MUs compared with IMRT. The reduction of treatment delivery time and MUs can decrease the effects of intrafractional uncertainties that can occur because of patient movement during treatment delivery. VMAT's plans further reduce doses to critical structures that are in close proximity to the target volume.

Define baseline levels of segments per beam for intensity-modulated radiation therapy delivery for brain, head and neck, thoracic, abdominal, and prostate applications.

The purpose of this study was to evaluate the number of segments per beam for intensity-modulated radiation therapy (IMRT) treatments and its effects on the plan quality, treatment delivery time, machine quality assurance, and machine maintenance. We have retrospectively analyzed 24 patients treated with IMRT. Five were selected within each of the following regions: head and neck, thoracic, abdomen, and prostate. Four patients were optimized within the brain region. The clinically treated plans were re-optimized using Philips Pinnacle3 v. 8 with the direct machine parameter optimization algorithm. The number of segments per beam from the treated plan was systematically reduced by 80%, 60%, 40%, and 30%, and the following statistics have been analyzed for plan quality: target min, mean, and max doses; critical structure doses; and integral dose. We have attempted to define the smallest number of segments per beam for IMRT treatment plans. Results indicate that IMRT plans can be delivered with acceptable quality with approximately 3-6 segments per beam for the anatomical regions analyzed. A reduction in the number of segments decreases treatment delivery time, reduces machine wear and tear, and minimizes the amount of time the patient is on the treatment table, which in turn reduces the chances of intrafractional uncertainties.