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OBJECTIVES: The aim of the present study was to assess the reproducibility of findings in cone beam computed tomography (CBCT) scout images. Furthermore, the study aimed to assess whether a scout image shows pathology not seen within the CBCT volume (ie, added diagnostic information) and therefore must be assessed on the same terms as the full volume. METHODS: Using a retrospective design, 233 CBCT reports and scout images were assessed. Kappa statistics and percentage of accordance were used to evaluate intra- and interobserver reproducibility as well as agreement between scout and CBCT report. RESULTS: Intra- and interobserver reproducibility were overall low (kappa ranging from -0.008 to 1.000). Agreement between findings reported in the CBCT and scout was also low. One-hundred-fourteen impacted teeth, one apical periodontitis, and two sinus conditions seen in the scout image were not registered in the full volume report due to the extended size of the scout image. CONCLUSIONS: Reproducibility of findings in scout images compared to CBCT volumes was low, and the scout showed very little additional diagnostic information. ADVANCES IN KNOWLEDGE: This study shows that although the reproducibility of viewing scout images is low, rare findings can go undetected if the scout is not assessed. Legislation regarding interpretation of scout images needs to be discussed.
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The negative effects of nutrient pollution in streams, rivers, and downstream waterbodies remain widespread global problems. Understanding the cost-effectiveness of different strategies for mitigating nutrient pollution is critical to making informed decisions and defining expectations that best utilize limited resources, which is a research priority for the US Environmental Protection Agency. To this end, we modeled nutrient management practices including residue management, cover crops, filter strips, grassed waterways, constructed wetlands, and reducing fertilizer in the upper East Fork of the Little Miami River, an 892 km2 watershed in southwestern Ohio, United States. The watershed is 64% agriculture with 422 km2 of row crops contributing an estimated 71% of the system's nutrient load. The six practices were modeled to treat row crop area, and among them, constructed wetlands ranked highest for their low costs per kilogram of nutrient removed. To meet a 42% phosphorus (P) reduction target for row crops, the model results suggested that the runoff from 85.5% of the row crop area would need to be treated by the equivalent of 3.61 km2 of constructed wetlands at an estimated cost of US$2.4 million annually (or US$48.5 million over a 20-year life cycle). This prompted a series of projects designed to understand the feasibility (defined in terms of build, treatment, and cost potential) of retrofitting the system with the necessary extent of constructed wetlands. The practicalities of building this wetland coverage into the system, while leading to innovation in unit-level design, has highlighted the difficulty of achieving the nutrient reduction target with wetlands alone. Approximately US$1.2 million have been spent on constructing 0.032 km2 of wetlands thus far and a feasibility analysis suggests a cost of US$38 million for an additional 0.409 km2. However, the combined expenditures would only achieve an estimated 13% of the required treatment. The results highlight the potential effectiveness of innovative design strategies for nutrient reduction and the importance of considering realistic field-scale build opportunities, which include accounting for acceptance among landowners, in watershed-scale nutrient reduction simulations using constructed wetlands.
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INTRODUCTION: Information on tissue perfusion in the foot is important when treating patients with chronic limb-threatening ischemia. This study aims to test the reliability of different magnetic resonance sequences when measuring perfusion in the foot. METHODS: Sixteen healthy volunteers had their right foot scanned in a test/retest study with six different magnetic resonance sequences (BOLD, multi-echo gradient echo (mGRE), 2D and 3D pCASL, PASL FAIR, and DWI with intravoxel incoherent motion (IVIM) with quantitative measurements of perfusion. For five sequences, cuff-induced ischemia followed by a hyperactive response was measured. Images of the feet were segmented into angiosomes and perfusion data were extracted from the five angiosomes. RESULTS: BOLD, PASL FAIR, mGRE, and DWI with IVIM had low mean differences between the first and second scans, while the results of 2D and 3D pCASL had the highest differences. Based on a paired t-test, BOLD, and FAIR were able to distinguish between perfusion and no perfusion in all angiosomes with p-values below 0.01. This was not the case with 2D and 3D pCASL with p-values above 0.05 in all angiosomes. The mGRE could not distinguish between perfusion and no perfusion in the lateral side of the foot. CONCLUSION: BOLD, mGRE, pASL FAIR, and DWI with IVIM seem to give more robust results compared to 2D and 3D pCASL. Further studies on patients with peripheral artery disease should explore if the sequences can have clinical relevance when assessing tissue ischemia and results of revascularization. IMPLICATIONS FOR PRACTICE: This study provides knowledge that could be used to improve the diagnosis of patient with chronic limb-threatening ischemia to explore tissue perfusion.
Subject(s)
Foot , Peripheral Arterial Disease , Humans , Peripheral Arterial Disease/diagnostic imaging , Peripheral Arterial Disease/therapy , Foot/blood supply , Foot/diagnostic imaging , Male , Female , Adult , Reproducibility of Results , Magnetic Resonance Imaging/methods , Middle Aged , Healthy Volunteers , Ischemia/diagnostic imaging , Magnetic Resonance Angiography/methodsABSTRACT
The DeLaval Herd Navigator is an on-farm sensor system that measures on a frequent basis milk progesterone (P4) and BHB in individual cows to closely monitor reproductive performance and energy balance. This information provides the opportunity to investigate the dynamics of BHB measured in milk (mBHB) and study the association between mBHB and early reproductive performance. The objectives of the study were (1) to describe mBHB dynamics within the first 20 DIM, and (2) to evaluate the association between mBHB dynamics and early reproductive performance at cow level. Two-year time-series data from 4,133 dairy cows in 38 Dutch dairy farms were available for analysis. Data included information on mBHB, daily milk yield, and the indicators of early reproductive performance, days from calving to resumption of cyclicity, days from calving to first estrus, and days from calving to first insemination. The following mBHB dynamic parameters were defined based on the first 20 DIM for each individual cow: average mBHB (AvgBHB), DIM when mBHB was for the first time ≥80 µmol/L (OnsetKeto), the total number of consecutive days a cow had mBHB concentration ≥80 µmol/L, and the number of measurements mBHB concentration was ≥80 µmol/L. Three Cox proportional hazard regression models with random herd effect were developed to evaluate the association between cow-level mBHB dynamics and days from calving to resumption of cyclicity, first estrus, and first insemination. Results showed that the mean AvgBHB within 20 DIM among all cows was 73 µmol/L. The mean OnsetKeto within 20 DIM, was 8 DIM. Among all cows having hyperketolactia, 55.8% (1,350/2,419) had OnsetKeto in the first week of lactation. In total, 41.5% (1,714/4,133) of the cows did not have OnsetKeto in the first 20 DIM. An early onset of hyperketolactia was associated with delayed fertility events. Cows with higher AvgBHB have a prolonged time interval from calving to resumption of cyclicity and first estrus. Information on mBHB dynamics and the association with early reproductive performance provides insights that might be helpful to improve reproductive performance of individual dairy cows.
Subject(s)
Lactation , Milk , Reproduction , Animals , Cattle/physiology , Female , Reproduction/physiology , Milk/chemistry , Milk/metabolism , 3-Hydroxybutyric Acid/blood , Progesterone/metabolism , PregnancyABSTRACT
Firocoxib is a COX-2-selective nonsteroidal anti-inflammatory drug (NSAID) with limited effects on COX-1, which means it likely has fewer side effects than typically associated with other NSAIDs. This study determined possible doses of firocoxib based on single- and multidose pharmacokinetic trials conducted in 10 Asian elephants (Elephas maximus). Initially, two single oral dose trials (0.01 and 0.1 mg/kg) of a commercially available tablet (n = 6) and paste (n = 4) formulation were used to determine a preferred dose. The 0.1 mg/kg dose was further evaluated via IV single dose (n = 3) and oral multidose trials (tablets n = 6; paste n = 4). Serum peak and trough firocoxib concentrations were also evaluated in Asian elephants (n = 4) that had been being treated for a minimum of 90 consecutive days. Key pharmacokinetic parameters for the 0.1 mg/kg single-dose trials included mean peak serum concentrations of 49 ± 3.3 ng/ml for tablets and 62 ± 14.8 ng/ml for paste, area under the curve (AUC) of 1,332 ± 878 h*mg/ml for tablets and 1,455 ± 634 h*mg/ml for paste, and half-life (T1/2) of 34.3 ± 30.3 h for tablets and 19.9 ± 12.8 h for paste. After 8 d of dosing at 0.1 mg/kg every 24 h, pharmacokinetic parameters stabilized to an AUC of 6,341 ± 3,003 h*mg/ml for tablets and 5,613 ± 2,262 for paste, and T1/2 of 84.4 ± 32.2 h for tablets and 62.9 ± 2.3 h for paste. Serum COX inhibition was evaluated in vitro and ex vivo in untreated elephant plasma, where firocoxib demonstrated preferential inhibition of COX-2. No adverse effects from firocoxib administration were identified in this study. Results suggest administering firocoxib to Asian elephants at a dose of 0.1 mg/kg orally, using either tablet or paste formulations, every 24 h.
Subject(s)
4-Butyrolactone/analogs & derivatives , Elephants , Sulfones , Animals , Cyclooxygenase 2 , Drug Monitoring , Administration, Oral , Anti-Inflammatory Agents, Non-Steroidal , Tablets , Area Under Curve , Cross-Over Studies , Half-LifeABSTRACT
Objective.The aim of this work is to investigate the dose rate dependence of thermoluminescence and optically stimulated luminescence detectors (TLDs and OSLDs) in a wide uniform ultra-high dose rate electron beam and demonstrate the potential use of TLDs and OSLDs to correct the ion recombination in air-filled ionization chambers. This study avoids previously reported complications related to the field size and homogeneity.Approach.Two types of OSLDs (BeO and Al2O3:C) and three types of TLDs (LiF:Mg,Ti, LiF:Mg,Cu,P, CaF2:Tm) were irradiated simultaneously in a uniform 16 MeV electron beam generated by a clinically decommissioned C-Arm LINAC, modified to deliver doses per pulse between 8.3 × 10-4Gy and 1.255 Gy, corresponding to instantaneous dose rates between 2 × 102Gy s-1and 3 × 105Gy s-1. A prototype ultra-thin parallel plate ionization chamber was employed as reference detector.Main results.Reproducible results were achieved both at conventional (standard deviation of the data <2%) and at the highest dose per pulse (standard deviation of the data <4%). No trend in the dose rate response of the TLDs and OSLDs was observed in the investigated dose per pulse range. The Al2O3:C OSLD was found to be the most precise detector, with a standard deviation of the data <2% at all investigated dose rates and dose levels.Significance.The dose rate independence of the investigated TLDs and OSLDs make them good candidates for dosimetry at ultra-high dose rates, at least up to 3 × 105Gy s-1. A dose rate independent method to measure the dose per pulse is proposed, which can be applied to characterize ultra-high dose rate electron beams and correct for ion recombination in ionization chambers.
Subject(s)
Optically Stimulated Luminescence Dosimetry , Electrons , Radiometry/methods , LuminescenceABSTRACT
Background: Living with chronic pain (CP) often implies major lifestyle changes, including modifications of daily routines and work. Surprisingly, few validated and effective interventions specifically target functional outcomes in this population. Redesign your Everyday Activities and Lifestyle with Occupational Therapy [REVEAL(OT)] is a lifestyle-oriented intervention led by occupational therapists that directly targets the daily functional challenges of living with CP. The intervention was initially developed and studied as an add-on to standard treatment delivered by Danish multidisciplinary specialized pain clinics. Adapting, implementing, and evaluating REVEAL(OT) within the Canadian healthcare system will contribute to broadening the scope of treatments offered in specialized pain clinics that do not yet include occupational therapy. Objective: The proposed study aims to define and refine REVEAL(OT)/CA with partners (authors of original intervention, people with lived experience, clinicians, managers). Methods: This participatory action research will use a multi-method design and follow the ORBIT model for developing behavioral treatments for chronic diseases. A process of co-construction with partners and an advisory committee will take place in two Montreal specialized pain clinics. It consists of two related work packages (WPs). In WP1, a first series of focus groups with partners (n = 86) and workshops with the advisory committee will be conducted to co-develop the hypothetical pathway describing intervention components and their potential mechanisms of action on targeted outcomes, as well as the first version of the adapted intervention manual. WP2 will co-refine REVEAL(OT)/CA by exploring its acceptability, feasibility and mechanisms of action through intervention deliveries (at least twice in each of two specialized pain clinics; n ≥ 60 patients) and focus groups and/or individual interviews with participating patients and partners. At the end of this study, the intervention manual will be generated both in French and English. Discussion: This study will set the stage for subsequent implementation and effectiveness assessment projects and be an important step towards the deployment of interventions aiming to improve engagement in meaningful daily activities among adults living with CP. Registration: OSF Registries, osf.io/8gksa. Registered 3 August 2023, https://osf.io/8gksa.
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BACKGROUND: The potential of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) as biomarkers of disease activity and severity in progressive forms of multiple sclerosis (MS) is unclear. OBJECTIVE: To investigate the relationship between serum concentrations of NfL, GFAP, and magnetic resonance imaging (MRI) in progressive MS. METHODS: Serum concentrations of NfL and GFAP were measured in 32 healthy controls and 32 patients with progressive MS from whom clinical and MRI data including diffusion tensor imaging (DTI) were obtained during three years of follow-up. RESULTS: Serum concentrations of NfL and GFAP at follow-up were higher in progressive MS patients than in healthy controls and serum NfL correlated with the EDSS score. Decreasing fractional anisotropy (FA) in normal-appearing white matter (NAWM) correlated with worsening EDSS scores and higher serum NfL. Higher serum NfL and increasing T2 lesion volume correlated with worsening paced autitory serial addition test scores. In multivariable regression analyses with serum GFAP and NfL as independent factors and DTI measures of NAWM as dependent factors, we showed that high serum NfL at follow-up was independently associated with decreasing FA and increasing MD in NAWM. Moreover, we found that high serum GFAP was independently associated with decreasing MD in NAWM and with decreasing MD and increasing FA in cortical gray matter. CONCLUSION: Serum concentrations of NfL and GFAP are increased in progressive MS and are associated with distinct microstructural changes in NAWM and CGM.
Subject(s)
Multiple Sclerosis, Chronic Progressive , Multiple Sclerosis , Humans , Multiple Sclerosis/pathology , Diffusion Tensor Imaging , Glial Fibrillary Acidic Protein , Intermediate Filaments/pathology , Multiple Sclerosis, Chronic Progressive/pathology , Gray Matter/diagnostic imaging , Gray Matter/pathology , Biomarkers , Brain/diagnostic imaging , Brain/pathologyABSTRACT
The time course of serum firocoxib concentrations was described after administration of two single oral doses (0.01 and 0.1 mg/kg) of commercially available firocoxib tablet (n = 4) and paste (n = 2) formulations to six healthy adult female African (Loxodonta africana) elephants. Firocoxib was quantitated by high-performance liquid chromatography. Firocoxib serum concentrations were below detectable levels after administration of 0.01 mg/kg of both formulations. A dose of 0.1 mg/kg (n = 4) of the tablet formulation had the following mean ± SD of pharmacokinetic parameters: area under the curve (AUC) 1,588 ± 362 h × ng/ml, maximum plasma concentration (Cmax) 31 ± 6.6 ng/ml at 6.4 ± 1.8 h, and disappearance half-life (T1/2) 66 ± 59 h, Elephant compliance to oral administration of the paste formulation was challenging, with only two elephants accepting administration of the paste at 0.1 mg/kg. Pharmacokinetic parameters determined included AUC of 814 h × ng/ml, Cmax of 44 ng/ml at Tmax of 7.0 h, and T1/2 of 36.4 h. Based on mean AUC, the relative bioavailability of paste compared to tablet formulations was 50%. Limitations of this study were the small number of participants and elephant compliance with the paste formulation. This study supports an oral dose of 0.1 mg/kg every 24 h. Multidose and IV trials are indicated to confirm firocoxib dosing requirements for African elephants.
Subject(s)
Elephants , Female , Animals , Sulfones/pharmacokinetics , 4-Butyrolactone/pharmacokinetics , Administration, Oral , Area Under Curve , Tablets , Cross-Over StudiesABSTRACT
BACKGROUND: Microsurgical free-tissue transfer is often the definitive reconstructive option for lower extremity limb salvage. Despite an initial successful free-flap reconstruction, some patients ultimately undergo lower extremity amputation. The indications for secondary amputation include non- or malunion, infection, hardware failure, or chronic pain. This study aimed to identify the etiology and outcome of secondary amputation after lower extremity free-flap reconstruction. METHODS: A retrospective cohort study was performed including patients who underwent lower extremity free-flap reconstruction from January 2002 to December 2020. Patients who underwent secondary amputation were identified. A survey based on the PROMIS® Pain Interference Scale and activities of daily living (ADLs) was then conducted to assess patient-reported outcomes. Fifteen (52%) patients who underwent amputation responded to the survey, with a median follow-up time of 4.4 years. RESULTS: Of 410 patients who underwent lower extremity free-flap reconstruction, 40 (9.8%) patients underwent subsequent amputation. Of these, 10 patients had failed free-flap reconstruction and 30 patients had secondary amputation after an initially successful soft tissue coverage. The most common etiology for secondary amputation was infection (68%, nâ¯=â¯27). Eighty percent (nâ¯=â¯12) of survey respondents were able to use a prosthetic limb and ambulate. CONCLUSIONS: The most common etiology of secondary amputation was infection. Most patients who ultimately underwent amputation were able to ambulate with a prosthetic, but the majority of patients reported chronic pain. This study could be used to guide potential free-flap candidates regarding the risks and outcomes of lower extremity free-flap reconstruction.
Subject(s)
Chronic Pain , Free Tissue Flaps , Plastic Surgery Procedures , Humans , Activities of Daily Living , Retrospective Studies , Plastic Surgery Procedures/adverse effects , Amputation, Surgical , Limb Salvage , Treatment OutcomeABSTRACT
Objective.This work aims at investigating the response of various thermally stimulated luminescence detectors (TLDs) and optically stimulated luminescence detectors (OSLDs) for dosimetry of ultra-high dose rate electron beams. The study was driven by the challenges of dosimetry at ultra-high dose rates and the importance of dosimetry for FLASH radiotherapy and radiobiology experiments.Approach.Three types of TLDs (LiF:Mg,Ti; LiF:Mg,Cu,P; CaF2:Tm) and one type of OSLD (Al2O3:C) were irradiated in a 15 MeV electron beam with instantaneous dose rates in the (1-324) kGy s-1range. Reference dosimetry was carried out with an integrating current transformer, which was calibrated in absorbed dose to water against a reference ionization chamber. Additionally, dose rate independent BeO OSLDs were employed as a reference. Beam non-uniformity was addressed using a matrix of TLDs/OSLDs.Main results.The investigated TLDs were shown to be dose rate independent within the experimental uncertainties, which take into account the uncertainty of the dosimetry protocol and the irradiation uncertainty. The relative deviation between the TLDs and the reference dose was lower than 4 % for all dose rates. A decreasing response with the dose rate was observed for Al2O3:C OSLDs, but still within 10 % from the reference dose.Significance.The precision of the investigated luminescence detectors make them suitable for dosimetry of ultra-high dose rate electron beams. Specifically, the dose rate independence of the TLDs can support the investigation of the beam uniformity as a function of the dose rate, which is one of the challenges of the employed beam. Al2O3:C OSLDs provided high precision measurements, but the decreasing response with the dose rate needs to be confirmed by additional experiments.
Subject(s)
Electrons , Radiometry , Radiometry/methods , Luminescence , WaterABSTRACT
BACKGROUND: Obesity can limit occupational participation because of physical and mental barriers. Weight loss programmes emphasizing dietary and physical activity may lower body weight; however, mental barriers and sustainable weight loss seemed to be challenged. Weight loss influences daily patterns and structure of occupations and finding a balance in daily life during the weight loss process might improve sustainable weight loss. AIM: To explore if and how health professionals conducting weight loss programmes in Danish municipalities address elements related to occupational balance in the daily life of citizens with obesity. MATERIAL AND METHODS: Twenty individual interviews with health professionals from Danish municipalities were conducted and analysed. RESULTS: (1) Helping participants find the time and energy to lose weight, (2) Emphasizing small steps for sustainable changes and (3) Utilizing the citizen's life experience for direction. CONCLUSION: Elements of occupational balance might be addressed by the participants, however values and meaningfulness regarding occupations seem to be missing. Integrating occupational balance in weight loss programmes could enable health professionals to understand and address sustainable weight loss. SIGNIFICANCE: Occupational therapists may be ideally suited to support citizens with obesity to sustain weight loss by supporting a balanced life focussing on meaningfulness and values in occupations.
Subject(s)
Obesity , Weight Loss , Humans , Obesity/therapy , Exercise , Occupational TherapistsABSTRACT
Orthodontists often encounter significant clinical challenges in the finishing stages of treatment due to a disproportion in interarch tooth size relationships. Despite the increasing presence of digital technology and concomitant focus on customized treatment approaches, there is a gap in the knowledge of how generating tooth size data using digital versus traditional methods may impact our treatment regime. OBJECTIVE: This study aimed to compare the prevalence of tooth size discrepancies using digital models and a digitally based cast analysis in our cohort based on (i) Angle's Classification; (ii) gender and (iii) race. MATERIALS AND METHODS: The mesiodistal widths of teeth in 101 digital models were assessed using computerized odontometric software. A Chi-square test was used to determine the prevalence of tooth size disproportions among the study groups. The differences between all three groups of the cohort were analysed using a three-way analysis of variance (ANOVA). RESULTS: An overall Bolton tooth size discrepancy (TSD) prevalence of 36.6% was observed in our study cohort; 26.7% had an anterior Bolton TSD. No differences existed in the prevalence of tooth size discrepancies between male and female subjects as well as between the different malocclusion groups (P > .05). Caucasian subjects had a statistically significant smaller prevalence of TSD compared to Black and Hispanic patients (P < .05). CONCLUSION: The prevalence results in this study illuminate how relatively common TSD is and underscores the importance of proper diagnosis. Our findings also suggest that racial background may be an influential factor in the presence of TSD.
Subject(s)
Malocclusion , Tooth , Female , Humans , Male , Odontometry/methods , Racial GroupsABSTRACT
Aim: To validate the Type 1 Diabetes Distress Scale (T1-DDS) in a large sample of adults with Type 1 diabetes (T1D) from diabetes clinics in Denmark. Methods: Altogether 40 adults with T1D were interviewed to explore the content of T1-DDS in a Danish setting and to validate the translation of the T1-DDS into Danish. Subsequently, a survey including T1-DDS, the Problem Areas In Diabetes scale (PAID-20), fear of hypoglycemia, social support, and diabetes duration was answered by 2201 people with T1D. Other person characteristics were collected from the National Patient Register. HbA1c was obtained from the Clinical Laboratory Information System. Data distribution, internal consistency, convergent and construct validity, factor structure, three weeks retest, and cut-points were explored. Results: Interview data supported the relevance of all T1-DDS items for the assessment of diabetes distress among adults with T1D. The T1-DDS showed good content and acceptable construct validity, and the ability to detect high diabetes distress levels. A high correlation between T1-DDS and PAID-20 (rho = 0.91) was found. The retest scores showed a good reliability (all rho ≥0.68) with the highest variability in the Friends/Family Distress and Physician Distress subscales and the lowest variability in the Powerlessness and Eating Distress subscales of the T1-DDS. Qualitative findings pointed out relevant concerns of people with T1D, which were not included in the T1-DDS. Conclusion: The study supports the use of the Danish T1-DDS, but also highlights that existing diabetes distress questionnaires including T1-DDS do not cover all potential diabetes stressors and worries.
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Objective.This work aims at characterizing LiF:Mg,Ti thermoluminescence detectors (TLDs) for dosimetry of a 250 MeV proton beam delivered at ultra-high dose rates (UHDR). Possible dose rate effects in LiF:Mg,Ti, as well as its usability for dosimetry of narrow proton beams are investigated.Approach.LiF:Mg,Ti (TLD-100TMMicrocubes, 1 mm × 1 mm × 1 mm) was packaged in matrices of 5 × 5 detectors. The center of each matrix was irradiated with single-spot low-LET (energy >244 MeV) proton beam in the (1-4500) Gy s-1average dose rates range. A beam reconstruction procedure was applied to the detectors irradiated at the highest dose rate (Gaussian beam sigma <2 mm) to correct for volumetric averaging effects. Reference dosimetry was carried out with a diamond detector and radiochromic films. The delivered number of protons was measured by a Faraday cup, which was employed to normalize the detector responses.Main results.The lateral beam spread obtained from the beam reconstruction agreed with the one derived from the radiochromic film measurements. No dose rates effects were observed in LiF:Mg,Ti for the investigated dose rates within 3% (k= 1). On average, the dose response of the TLDs agreed with the reference detectors within their uncertainties. The largest deviation (-5%) was measured at 4500 Gy s-1.Significance.The dose rate independence of LiF:Mg,Ti TLDs makes them suitable for dosimetry of UHDR proton beams. Additionally, the combination of a matrix of TLDs and the beam reconstruction can be applied to determine the beam profile of narrow proton beams.
Subject(s)
Protons , Radioactivity , Titanium , Thermoluminescent Dosimetry/methods , Radiometry/methodsABSTRACT
INTRODUCTION: The objective of this investigation was to compare different techniques to improve visualization and reduction in tibial plateau fractures involving the central lateral segments. METHODS: Matched pairs of pre-fractured cadaveric tibial plateau fractures that include the central lateral segments were treated by either an anterolateral approach (supine) or PL approach (prone). Reduction was stepwise extended by additional fracturoscopy (FS), nanoscopy (NS) and lastly by epicondyle osteotomy (ECO). Reduction was analyzed by 3D scan and visualization of the lateral plateau was quantified. RESULTS: Ten specimens (3 pairs 41B3.1, 2 pairs 41C3.3) were analyzed. Fracture steps involving the antero-latero-central (ALC) segment were insufficiently reduced after fluoroscopy using both approaches (AL 2.2 ± 1.2 mm vs PL 2.2 ± 1.0 mm, p 0.95). Additional NS and ECO achieved optimized fracture reduction in the ALC segment (NS AL 1.6 ± 1.3 mm vs PL 0.8 ± 0.9 mm, p 0.32). NS provided visualization of the entire lateral plateau (PL 102.9% ± 7.4, AL 108.8 ± 19.2%), while fracturoscopy only allowed visualization of the ALL segment and partially of PLL and ALC segments (PL 22.0 ± 23.4%, AL 29.7 ± 18.3%). CONCLUSION: Optimized reduction of tibial head fractures with involvement of latero-central segments requires additional video-assisted reduction or extended approaches. Nanoscopy helps visualizing of the entire lateral plateau, when compared to fracturoscopy and may become a valuable reduction aid.
Subject(s)
Tibial Fractures , Tibial Plateau Fractures , Humans , Fracture Fixation, Internal/methods , Tibial Fractures/diagnostic imaging , Tibial Fractures/surgery , Tibia/diagnostic imaging , Tibia/surgery , Cadaver , Treatment OutcomeABSTRACT
PURPOSE: Effects of component separation (CS) on abdominal wall morphology have only been investigated in smaller case series or cadavers. This study aimed to compare abdominal wall alterations following endoscopic anterior CS (EACS) or open transverse abdominis release (TAR). METHODS: Computed tomography scans were evaluated in patients who had undergone open incisional hernia repair with EACS or TAR. Abdominal wall circumference, lateral abdominal wall muscle thickness, and displacement were compared with (1) preoperative images after bilateral CS and (2) the undivided side postoperatively after unilateral CS. RESULTS: In total, 105 patients were included. Fifty-five (52%) and 15 (14%) underwent bilateral and unilateral EACS, respectively. Five (5%) and 14 (13%) underwent bilateral and unilateral TAR, respectively. Sixteen (15%) underwent unilateral EACS and contralateral TAR. The external oblique and transverse abdominis muscles were significantly laterally displaced with a mean of 2.74 cm (95% CI 2.29-3.19 cm, P < 0.001) and 0.82 cm (0.07-1.57 cm, P = 0.032) after EACS and TAR, respectively. The combined thickness of the lateral muscles was significantly decreased after EACS (mean decrease 10.5% (5.8-15.6%, P < 0.001)) and insignificantly decreased after TAR (mean decrease 2.6% (- 4.8 to 9.5%, P = 0.50)). The abdominal wall circumference was unchanged after bilateral (mean reduction 0.90 cm (- 0.77 to 2.58 cm), P = 0.29) and unilateral CS (mean increase 0.03 cm (- 1.01 to 1.08 cm), P = 0.95). CONCLUSION: Postoperative changes in the lateral abdominal wall musculature were different following EACS and open TAR. Either technique seems not to compromise the overall integrity of the lateral abdominal wall.
Subject(s)
Abdominal Wall , Hernia, Ventral , Incisional Hernia , Humans , Abdominal Wall/surgery , Hernia, Ventral/surgery , Abdominal Muscles/surgery , Incisional Hernia/surgery , Herniorrhaphy/methods , Surgical MeshABSTRACT
PURPOSE: To characterize an experimental setup for ultra-high dose rate (UHDR) proton irradiations, and to address the challenges of dosimetry in millimetre-small pencil proton beams. METHODS: At the PSI Gantry 1, high-energy transmission pencil beams can be delivered to biological samples and detectors up to a maximum local dose rate of â¼9000 Gy/s. In the presented setup, a Faraday cup is used to measure the delivered number of protons up to ultra-high dose rates. The response of transmission ion-chambers, as well as of different field detectors, was characterized over a wide range of dose rates using the Faraday cup as reference. RESULTS: The reproducibility of the delivered proton charge was better than 1 % in the proposed experimental setup. EBT3 films, Al2O3:C optically stimulated luminescence detectors and a PTW microDiamond were used to validate the predicted dose. Transmission ionization chambers showed significant volume ion-recombination (>30 % in the tested conditions) which can be parametrized as a function of the maximum proton current density. Over the considered range, EBT3 films, inorganic scintillator-based screens and the PTW microDiamond were demonstrated to be dose rate independent within ±3 %, ±1.8 % and ±1 %, respectively. CONCLUSIONS: Faraday cups are versatile dosimetry instruments that can be used for dose estimation, field detector characterization and on-line dose verification for pre-clinical experiments in UHDR proton pencil beams. Among the tested detectors, the commercial PTW microDiamond was found to be a suitable option to measure real time the dosimetric properties of narrow pencil proton beams for dose rates up to 2.2 kGy/s.
Subject(s)
Protons , Reproducibility of ResultsABSTRACT
The relationships between dairy cow milk-based energy status (ES) indicators and fertility traits were studied during periods 8 to 21, 22 to 35, 36 to 49, and 50 to 63 d in milk. Commencement of luteal activity (C-LA) and interval from calving to the first heat (CFH), based on frequent measurements of progesterone by the management tool Herd Navigator (DeLaval), were used as fertility traits. Energy status indicator traits were milk ß-hydroxybutyrate (BHB) concentration provided by Herd Navigator and milk fat:protein ratio, concentration of C18:1 cis-9, the ratio of fatty acids (FA) C18:1 cis-9 and C10:0 in test-day milk samples, and predicted plasma concentration of nonesterified fatty acids (NEFA) on test days. Plasma NEFA predictions were based either directly on milk mid-infrared spectra (MIR) or on milk fatty acids based on MIR spectra (NEFAmir and NEFAfa, respectively). The average (standard deviation) C-LA was 39.3 (±16.6) days, and the average CFH was 50.7 (±17.2) days. The correlations between fertility traits and ES indicators tended to be higher for multiparous (r < 0.28) than for primiparous (r < 0.16) cows. All correlations were lower in the last period than in the other periods. In period 1, correlations of C-LA with NEFAfa and BHB, respectively, were 0.15 and 0.14 for primiparous and 0.26 and 0.22 for multiparous cows. The associations between fertility traits and ES indicators indicated that negative ES during the first weeks postpartum may delay the onset of luteal activity. Milk FPR was not as good an indicator for cow ES as other indicators. According to these findings, predictions of plasma NEFA and milk FA based on milk MIR spectra of routine test-day samples and the frequent measurement of milk BHB by Herd Navigator gave equally good predictions of cow ES during the first weeks of lactation. Our results indicate that routinely measured milk traits can be used for ES evaluation in early lactation.