bluuebunny/crossref_metadata_2025_split huggingface dataset:
Segmentation of organs‐at‐risks in head and neck CT images using convolutional neural networks
Authors: Ibragimov Bulat , Xing Lei 
Published: December 2016

PurposeAccurate segmentation of organs‐at‐risks (OARs) is the key step for efficient planning of radiation therapy for head and neck (HaN) cancer treatment. In the work, we proposed the first deep learning‐based algorithm, for segmentation of OARs in HaN CT images, and compared its performance against state‐of‐the‐art automated segmentation algorithms, commercial software, and interobserver variability.MethodsConvolutional neural networks (CNNs)—a concept from the field of deep learning—were used to study consistent intensity patterns of OARs from training CT images and to segment the OAR in a previously unseen test CT image. For CNN training, we extracted a representative number of positive intensity patches around voxels that belong to the OAR of interest in training CT images, and negative intensity patches around voxels that belong to the surrounding structures. These patches then passed through a sequence of CNN layers that captured local image features such as corners, end‐points, and edges, and combined them into more complex high‐order features that can efficiently describe the OAR. The trained network was applied to classify voxels in a region of interest in the test image where the corresponding OAR is expected to be located. We then smoothed the obtained classification results by using Markov random fields algorithm. We finally extracted the largest connected component of the smoothed voxels classified as the OAR by CNN, performed dilate–erode operations to remove cavities of the component, which resulted in segmentation of the OAR in the test image.ResultsThe performance of CNNs was validated on segmentation of spinal cord, mandible, parotid glands, submandibular glands, larynx, pharynx, eye globes, optic nerves, and optic chiasm using 50 CT images. The obtained segmentation results varied from 37.4% Dice coefficient (DSC) for chiasm to 89.5% DSC for mandible. We also analyzed the performance of state‐of‐the‐art algorithms and commercial software reported in the literature, and observed that CNNs demonstrate similar or superior performance on segmentation of spinal cord, mandible, parotid glands, larynx, pharynx, eye globes, and optic nerves, but inferior performance on segmentation of submandibular glands and optic chiasm.ConclusionWe concluded that convolution neural networks can accurately segment most of OARs using a representative database of 50 HaN CT images. At the same time, inclusion of additional information, for example, MR images, may be beneficial to some OARs with poorly visible boundaries.
Feasibility of external beam radiation therapy to deep‐seated targets with kilovoltage x‐rays
Authors: Bazalova‐Carter Magdalena , Weil Michael D. , Breitkreutz Dylan Yamabe , Wilfley Brian P. , Graves Edward E. 
Published: December 2016

PurposeRadiation therapy to deep‐seated targets is typically delivered with megavoltage x‐ray beams generated by medical linear accelerators or 60Co sources. Here, we used computer simulations to design and optimize a lower energy kilovoltage x‐ray source generating acceptable dose distributions to a deep‐seated target.MethodsThe kilovoltage arc therapy (KVAT) x‐ray source was designed to treat a 4‐cm diameter target located at a 10‐cm depth in a 40‐cm diameter homogeneous cylindrical phantom. These parameters were chosen as an example of a clinical scenario for testing the performance of the kilovoltage source. A Monte Carlo (MC) model of the source was built in the EGSnrc/BEAMnrc code and source parameters, such as beam energy, tungsten anode thickness, beam filtration, number of collimator holes, collimator hole size and thickness, and source extent were varied. Dose to the phantom was calculated in the EGSnrc/DOSXYZnrc code for varying treatment parameters, such as the source‐to‐axis distance and the treatment arc angle. The quality of dose distributions was quantified by means of target‐to‐skin ratio and dose output expressed in D50 (50% isodose line) for a 30‐min irradiation in the homogeneous phantom as well as a lung phantom. Additionally, a patient KVAT dose distribution to a left pararenal lesion (~1.6 cm in diameter) was calculated and compared to a 15 MV volumetric modulated arc therapy (VMAT) plan.ResultsIn the design of the KVAT x‐ray source, the beam energy, beam filtration, collimator hole size, source‐to‐isocenter distance, and treatment arc had the largest effect on the source output and the quality of dose distributions. For the 4‐cm target at 10‐cm depth, the optimized KVAT dose distribution generated a conformal plan with target‐to‐skin ratio of 5.1 and D50 in 30 min of 24.1 Gy in the homogeneous phantom. In the lung phantom, a target‐to‐skin ratio of 7.5 and D50 in 30 min of 25.3 Gy were achieved. High dose conformity of the 200 kV KVAT left pararenal plan was comparable to the 15 MV VMAT plan. The volume irradiated to at least 10% (<240 cGy) of the prescription dose was 2.2 × larger in the 200 kV KVAT plan than in the 15 MV VMAT plan, but considered clinically insignificant.ConclusionsThis study demonstrated that conformal treatments of deep‐seated targets were achievable with kilovoltage x‐rays with dose distributions comparable to MV beams. However, due to the larger volumes irradiated to clinically tolerated low doses, KVAT x‐ray source usage for deep‐seated lesions will be further evaluated to determine optimal target size.
A feasibility study of a deuterium–deuterium neutron generator‐based boron neutron capture therapy system for treatment of brain tumors
Authors: Hsieh Mindy , Liu Yingzi , Mostafaei Farshad , Poulson Jean M. , Nie Linda H. 
Published: December 2016

PurposeBoron neutron capture therapy (BNCT) is a binary treatment modality that uses high LET particles to achieve tumor cell killing. Deuterium–deuterium (DD) compact neutron generators have advantages over nuclear reactors and large accelerators as the BNCT neutron source, such as their compact size, low cost, and relatively easy installation. The purpose of this study is to design a beam shaping assembly (BSA) for a DD neutron generator and assess the potential of a DD‐based BNCT system using Monte Carlo (MC) simulations.MethodsThe MC model consisted of a head phantom, a DD neutron source, and a BSA. The head phantom had tally cylinders along the centerline for computing neutron and photon fluences and calculating the dose as a function of depth. The head phantom was placed at 4 cm from the BSA. The neutron source was modeled to resemble the source of our current DD neutron generator. A BSA was designed to moderate and shape the 2.45‐MeV DD neutrons to the epithermal (0.5 eV to 10 keV) range. The BSA had multiple components, including moderator, reflector, collimator, and filter. Various materials and configurations were tested for each component. Each BSA layout was assessed in terms of the in‐air and in‐phantom parameters. The maximum brain dose was limited to 12.5 Gray‐Equivalent (Gy‐Eq) and the skin dose to 18 Gy‐Eq.ResultsThe optimized BSA configuration included 30 cm of lead for reflector, 45 cm of LiF, and 10 cm of MgF2 for moderator, 10 cm of lead for collimator, and 0.1 mm of cadmium for thermal neutron filter. Epithermal flux at the beam aperture was 1.0 × 105 nepi/cm2‐s; thermal‐to‐epithermal neutron ratio was 0.05; fast neutron dose per epithermal was 5.5 × 10−13 Gy‐cm2/φepi, and photon dose per epithermal was 2.4 × 10−13 Gy‐cm2/φepi. The AD, AR, and the advantage depth dose rate were 12.1 cm, 3.7, and 3.2 × 10−3 cGy‐Eq/min, respectively. The maximum skin dose was 0.56 Gy‐Eq. The DD neutron yield that is needed to irradiate in reasonable time was 4.9 × 1013 n/s.ConclusionsResults demonstrated that a DD‐based BNCT system could be designed to produce neutron beams that have acceptable in‐air and in‐phantom characteristics. The parameter values were comparable to those of existing BNCT facilities. Continuing efforts are ongoing to improve the DD neutron yield.
Commissioning of the Leksell Gamma Knife® Icon™
Authors: Zeverino Michele , Jaccard Maud , Patin David , Ryckx Nick , Marguet Maud , Tuleasca Constantin , Schiappacasse Luis , Bourhis Jean , Levivier Marc , Bochud Francois O. , Moeckli Raphaël 
Published: December 2016

PurposeThe Leksell Gamma Knife (LGK) Icon has been recently introduced to provide Gamma Knife technology with frameless stereotactic treatments which use an additional cone‐beam CT (CBCT) imaging system and a motion tracking system (IFMM, Intra‐Fraction Motion Management). The system was commissioned for the treatment unit itself as well as the imaging system.MethodsThe LGK Icon was calibrated using an A1SL ionization chamber. EBT3 radiochromic films were employed to independently check the machine calibration, to measure the relative output factors (ROFs) and to collect dose distributions. Coincidence between CBCT isocenter and radiological focus was evaluated by means of EBT3 films. CBCT image quality was investigated in terms of spatial resolution, contrast‐to‐noise ratio (CNR), and uniformity for the two presets available (low dose and high dose). Computed Tomography Dose Index (CTDI) was also measured for both presets.ResultsThe absolute dose rate of the LGK Icon was 3.86 ± 0.09 Gy/min. This result was confirmed by EBT3 readings. ROF were found to be 0.887 ± 0.035 and 0.797 ± 0.032 for the 8 mm and 4 mm collimators, respectively, which are within 2% of the Monte Carlo‐derived ROF values. Excellent agreement was found between calculated and measured dose distribution with the gamma pass rate >95% of points for the nine dose distributions analyzed with 3%/1 mm criteria. CBCT isocenter was found to be within 0.2 mm with respect to radiological focus. Image quality parameters were found to be well within the manufacturer's specifications with the high‐dose preset being superior in terms of CNR and uniformity. CTDI values were 2.41 mGy and 6.32 mGy, i.e. −3.6% and 0.3% different from the nominal values for the low‐dose and high‐dose presets, respectively.ConclusionsThe LGK Icon was successfully commissioned for clinical use. The use of the EBT3 to characterize the treatment unit was demonstrated to be feasible. The CBCT imaging system operates well within the manufacturer's specifications and provides good geometrical accuracy.
A systematic review of dyadic studies examining relationship quality in couples facing colorectal cancer together
Authors: Kayser Karen , Acquati Chiara , Reese Jennifer Barsky , Mark Kristen , Wittmann Daniela , Karam Eli 
Published: December 2016

AbstractBackgroundDespite the adverse effects that treatment for colorectal cancer can have on patients' quality of life and, in particular, their intimate relationships, very little research has been conducted on the psychosocial adjustment for both patients and their partners/spouses.ObjectivesThe aim of this systematic review was to examine dyadic studies of adjustment in couples in which one partner has been diagnosed with colorectal cancer.MethodsPub Med, PsychINFO, MEDLINE, Social Sciences Abstracts (EBSCO), and the Cochrane Library were systematically searched for studies reporting quality of life outcomes for colorectal cancer patients and their partners/spouses. Only studies that included dyads in the sample were eligible for inclusion. The Quality Assessment Tool for Quantitative Studies was used to evaluate each study.ResultsA total of 277 studies were identified, of which 9 studies met the inclusion criteria (N = 388 couples). The methodological quality of the studies was high in that they used standardized instruments validated with their samples, conducted dyadic data analyses (when appropriate), and used longitudinal designs. A synthesis of the studies revealed that (1) relationship factors (eg, support, communication, dyadic coping, and relationship satisfaction) affect adjustment to cancer; (2) cancer‐related distress impacts each partner's adjustment or the relationship; and (3) gender, role (patient/caregiver), and clinical characteristics (treatment, mental health) can mediate adjustment to cancer.ConclusionThe quality of the relationship can influence patients' and their partners' adjustment to colorectal cancer. Psychosocial interventions that address relationship issues may be beneficial to couples facing the challenges of colorectal cancer.
Balancing give and take between patients and their spousal caregivers in hematopoietic stem cell transplantation
Authors: Beattie Sara , Lebel Sophie , Petricone‐Westwood Danielle , Wilson Keith G. , Harris Cheryl , Devins Gerald , Huebsch Lothar , Tay Jason 
Published: December 2016

AbstractObjectiveHematopoietic stem cell transplantation (HSCT) is a demanding treatment. Spouses of HSCT patients assume caregiving responsibilities that can induce feelings of burden and disrupt relationship equity. On the basis of equity theory, we propose a conceptual framework examining the individual and dyadic experience of HSCT patients and their caregivers. The model includes feelings of inequity, patient self‐perceived burden, caregiver burden, and distress.MethodsThe HSCT patients and their spousal caregivers were recruited prior to HSCT between March 2011 and September 2012. Each member of the dyad self‐administered a questionnaire package.ResultsSeventy‐two dyads were included in the path analyses. Our model demonstrated an inadequate statistical fit; however, with one modification, an adequate to good fit was obtained: χ2(df) = 6.01(5), normed χ2 = 1.20, standardized root mean square residual = 0.048, comparative fit index = 0.99, Tucker‐Lewis index = 0.96, and root‐mean‐square error of approximation = 0.05 (90% CI, 0.00‐0.18). As hypothesized, pre‐HSCT caregiver burden mediates the relationship between caregiver underbenefit and caregiver distress. However, patient self‐perceived burden was not associated with patient distress; rather, patient perception of overbenefit was related to patient distress. In our modified model, the results demonstrate that patient overbenefit influenced caregiver burden; however, there was not a reciprocal influence, because caregiver variables did not affect patient variables.ConclusionsOur proposed theoretical framework describes patients' and caregivers' individual experience of distress before HSCT but does not as clearly encompass the dyadic experience. Addressing perceived imbalances and providing psycho‐education on role changes within HSCT dyads before transplantation may be a useful prehabilitation strategy for preventing distress.
Trajectories of quality of life, life satisfaction, and psychological adjustment after prostate cancer
Authors: Chambers Suzanne K. , Ng Shu Kay , Baade Peter , Aitken Joanne F. , Hyde Melissa K. , Wittert Gary , Frydenberg Mark , Dunn Jeff 
Published: December 2016

AbstractBackgroundTo describe trajectories of health‐related quality of life (QoL), life satisfaction, and psychological adjustment for men with prostate cancer over the medium to long term and identify predictors of poorer outcomes using growth mixture models.MethodsOne‐thousand sixty‐four (82.4% response) men diagnosed with prostate cancer were recruited close to diagnosis and assessed over a 72‐month (6‐year) period with self‐report assessment of health‐related QoL, life satisfaction, cancer‐related distress, and prostate specific antigen anxiety. Urinary, bowel, and sexual function were also assessed using validated questionnaires.ResultsPoorer physical QOL was predicted by older age, lower education, lower income, comorbidities, and receiving hormone therapy. Lower life satisfaction was related to younger age, lower income, not being partnered, and comorbidities. Poorer psychological trajectories were predicted by younger age, lower income, comorbidities, and receiving radical prostatectomy or brachytherapy. Better urinary, bowel, and sexual function were related to better global outcomes over time. Anxiety about prostate specific antigen testing was rare.ConclusionsDistinct trajectories exist for medium‐ to long‐term QoL, life satisfaction, and psychological adjustment after prostate cancer; with age and socioeconomic deprivation playing a differential role in men's survivorship profile and the impact of functional status on outcomes increasing over time. These results reinforce the need for an appraisal of men's life course in addition to treatment side effects when planning survivorship care after cancer.
Posttraumatic growth in breast cancer survivors and their husbands based on the actor‐partner interdependence model
Authors: Lee MyoSuk , Kim Kyunghee , Lim Changwon , Kim Ji‐Su 
Published: December 2016

AbstractObjectiveThis study aimed to verify actor and partner effects, by examining the effects of self‐esteem, relationship quality, and subjective distress on posttraumatic growth in breast cancer survivors and their spouses, and involved a structural analysis of descriptive cause‐and‐effect relationships to verify the suitability of the actor‐partner interdependence model.MethodsA structured questionnaire was used to collect data from breast cancer survivors and their spouses at outpatient centers, wards, and patient meetings in 4 general hospitals in Seoul between April 13 and September 20, 2015. Data for 336 individuals (168 couples) were analyzed. The suitability of the hypothetical model was assessed via SPSS Win 21.0 and AMOS 21.0. Actor and partner effects on posttraumatic growth in breast cancer survivors and their spouses were examined.ResultsSelf‐esteem, relationship quality, and subjective distress exerted significant actor effects, and subjective distress exerted a significant partner effect on posttraumatic growth in breast cancer survivors. Relationship quality and support exerted significant actor effects, and self‐esteem, relationship quality, and subjective distress exerted significant partner effects on posttraumatic growth in spouses.ConclusionsPosttraumatic growth in breast cancer survivors was influenced by not only relationship quality and spouses' self‐ esteem but also subjective distress; therefore, solidarity between breast cancer survivors and their spouses was important and should be maintained to provide healthy relationship support and enhance posttraumatic growth. Further, health care providers should include spouses in health‐related education and involve them in interventions and family support programs for couples.
A comparison of attitudes toward length and quality of life between community‐dwelling older adults and patients with advanced cancer
Authors: Malhotra Chetna , Xiang Ling , Ozdemir Semra , Kanesvaran Ravindran , Chan Noreen , Finkelstein Eric Andrew 
Published: December 2016

AbstractObjectiveApplying prospect theory to end‐of‐life decision making, we hypothesize that community‐dwelling older adults (CDOAs) will be relatively less inclined towards extending length over improving quality of life compared with patients. We also hypothesize that differences in relative inclination for length over quality of life between the 2 groups will decrease with advancing age.MethodsWe tested these hypotheses by administering the quality‐quantity questionnaire to 1067 CDOAs and 320 stage IV cancer patients and applying a linear regression model to assess whether relative inclination for length over quality of life, as estimated by the questionnaire, differed between CDOAs and patients after controlling for differences in sociodemographic characteristics. We also assessed the effect of interaction between age and participant status (CDOA compared to patient) on relative inclination for length over quality of life.ResultsConsistent with prospect theory, a lower proportion of CDOAs (26%) than patients (42%) were relatively more inclined towards length over quality of life. Results were significant even after adjusting for differences in sociodemographics (P < .01). With increasing age, the difference in relative inclination between CDOAs and patients increased (P = .01).ConclusionsFindings indicate that attitudes towards length and quality of life differ by life stage. This has implications for end‐of‐life care decisions made by CDOAs, such as purchasing health or disability insurance and signing advance directives or care plans.
Cross‐resistance to three phenylpyrazole insecticides and A2′N mutation detection of GABA receptor subunit in fipronil‐resistant Laodelphax striatellus (Hemiptera: Delphacidae)
Authors: Wei Qi , Mu Xi‐Chao , Wu Shun‐Fan , Wang Li‐Xiang , Gao Cong‐Fen 
Published: December 2016

AbstractBACKGROUNDLaodelphax striatellus (Fallén) is an important pest of crops in East Asia. Over the past decade, phenylpyrazole insecticides, which target the insect GABA receptor, have increasingly been used as alternatives against rice planthoppers.RESULTSCross‐resistance to ethiprole and butene‐fipronil was detected in a laboratory‐selected fipronil‐resistant strain of L. striatellus (LsFR). Compared with a fipronil‐susceptible strain (LsFS), LsFR had obtained a high‐level resistance to fipronil (112.1‐fold) and moderate resistance to ethiprole (24.5‐fold) and butene‐fipronil (14.7‐fold). For the resistance of field populations, LC50 values of ethiprole were remarkably higher than the other two analogues in Gaochun and Yancheng populations in 2016. Significant correlations were demonstrated between the LC50 values of three phenylpyrazole insecticides (R = 0.944‐0.998, P = 0.007–0.016). Additionally, an AS‐PCR assay was developed to detect the A2′N mutant GABA receptor in L. striatellus strains or populations. It was noteworthy that mutation frequencies of 19.2 and 3.6% appeared in Lujiang and Gaochun populations in 2016, respectively. Furthermore, there was an extremely significant difference in genomic expression of Lsrdl between the LsFS and LsFR individuals (1.85‐fold, F = 26.8, P = 0.0008).CONCLUSIONSThis study could help us better understand the cross‐resistance mechanisms in L. striatellus, and be beneficial for proposing effective pest management strategies of phenylpyrazole resistance. © 2016 Society of Chemical Industry