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Practical guidelines that are not explicit in the TG‐51 protocol and its Addendum for photon beam dosimetry are presented for the implementation of the TG‐51 protocol for reference dosimetry of external high‐energy photon and electron beams. These guidelines pertain to: (i) measurement of depth‐ionization curves required to obtain beam quality specifiers for the selection of beam quality conversion factors, (ii) considerations for the dosimetry system and specifications of a reference‐class ionization chamber, (iii) commissioning a dosimetry system and frequency of measurements, (iv) positioning/aligning the water tank and ionization chamber for depth ionization and reference dose measurements, (v) requirements for ancillary equipment needed to measure charge (triaxial cables and electrometers) and to correct for environmental conditions, and (vi) translation from dose at the reference depth to that at the depth required by the treatment planning system. Procedures are identified to achieve the most accurate results (errors up to 8% have been observed) and, where applicable, a commonly used simplified procedure is described and the impact on reference dosimetry measurements is discussed so that the medical physicist can be informed on where to allocate resources. [ABSTRACT FROM AUTHOR]

Purpose: Well‐designed routine multileaf collimator (MLC) quality assurance (QA) is important to assure external‐beam radiation treatment delivery accuracy. This study evaluates the clinical necessity of a comprehensive weekly (C‐Weekly) MLC QA program compared to the American Association of Physics in Medicinerecommended weekly picket fence test (PF‐Weekly), based on our seven‐year experience with weekly MLC QA. Methods: The C‐Weekly MLC QA program used in this study includes 5 tests to analyze: (1) absolute MLC leaf position; (2) interdigitation MLC leaf position; (3) picket fence MLC leaf positions at static gantry angle; (4) minimum leaf‐gap setting; and (5) volumetric‐modulated arc therapy delivery. A total of 20,226 QA images from 16,855 tests (3,371 tests × 5) for 11 linacs at 5 photon clinical sites from May 2014 to June 2021 were analyzed. Failure mode and effects analysis was performed with 5 failure modes related to the 5 tests. For each failure mode, a risk probability number (RPN) was calculated for a C‐Weekly and a PF‐Weekly MLC QA program. The probability of occurrence was evaluated from statistical analyses of the C‐Weekly MLC QA. Results: The total number of failures for these 16,855 tests was 143 (0.9%): 39 (27.3%) for absolute MLC leaf position, 13 (9.1%) for interdigitation position, 9 (6.3%) for static gantry picket fence, 2 (1.4%) for minimum leaf‐gap setting, and 80 (55.9%) for VMAT delivery. RPN scores for PF‐Weekly MLC QA ranged from 60 to 192 and from 48 to 96 for C‐Weekly MLC QA. Conclusion: RPNs for the 5 failure modes of MLC QA tests were quantitatively determined and analyzed. A comprehensive weekly MLC QA is imperative to lower the RPNs of the 5 failure modes to the desired level (<125); those from the PF‐Weekly MLC QA program were found to be higher (>125). This supports the clinical necessity for comprehensive weekly MLC QA. [ABSTRACT FROM AUTHOR]

Purpose: The recently published AAPM TG‐275 and the public review version of TG‐315 list new recommendations for comprehensive and minimum physics initial chart checks, respectively. This article addresses the potential development and benefit of initial chart check automation when these recommendations are implemented for clinical photon/electron EBRT. Methods: Eight board‐certified physicists with 2–20 years of clinical experience performed initial chart checks using checklists from TG‐275 and TG‐315. Manual check times were estimated for three types of plans (IMRT/VMAT, 3D, and 2D) and for prostate, whole pelvis, lung, breast, head and neck, and brain cancers. An expert development team of three physicists re‐evaluated the automation feasibility of TG‐275 checklist based on their experience of developing and implementing the in‐house and the commercial automation tools in our institution. Three levels of initial chart check automation were simulated: (1) Auto_UMMS_tool (which consists of in‐house program and commercially available software); (2) Auto_TG275 (with full and partial automation as indicated in TG‐275); and (3) Auto_UMMS_exp (with full and partial automation as determined by our experts' re‐evaluation). Results: With no automation of initial chart checks, the ranges of manual check times were 29–56 min (full TG‐315 list) and 102–163 min (full TG‐275 list), which varied significantly with physicists but varied little at different tumor sites. The 69 of 71 checks which were considered as "not fully automated" in TG‐275 were re‐evaluated with more automation feasibility. Compared to no automation, the higher levels of automation yielded a great reduction in both manual check times (by 44%–98%) and potentially residual detectable errors (by 15–85%). Conclusion: The initial chart check automation greatly improves the practicality and efficiency of implementing the new TG recommendations. Revisiting the TG reports with new technology/practice updates may help develop and utilize more automation clinically. [ABSTRACT FROM AUTHOR]

Background: Serine is a hypoallergenic but inefficient chemical exfoliant. Serine paired with arginine (ion‐paired amino acid, IPA) shows enhanced lipophilicity, skin permeation, and exfoliation efficacy. Aim: This study was conducted to determine whether exfoliation using an emulsion containing IPA could reduce enlarged facial pores and improve the dermis density. Methods: IPA formation was validated by spectroscopic analysis. Enhanced permeability and exfoliation efficacy were evaluated ex vivo using porcine skin. In a clinical trial, healthy Korean women aged 20‐49 years (mean age ± SD: 35.6 ± 8.6, n = 64) were evaluated, and the right and left sides of the cheeks were randomly chosen. An emulsion containing 4.0% IPA and placebo emulsion were applied to each side for 6 weeks. To evaluate pore sizes following treatment, the number of enlarged facial pores, inner skin structures from the stratum corneum to epidermal‐dermal interface, and dermal density on each cheek of the participants were assessed. Results: IPA showed a significantly increased partition coefficient in n‐octanol‐water. In porcine skin, permeation of serine after 12 hour was 70% higher for the IPA than for serine alone at the same percent weight concentrations. In the clinical trial, after 6 weeks, the number of enlarged facial pores was changed by −19.317% in the IPA emulsion group (P <.001) and −2.930% in placebo emulsion group (P =.254). Conclusion: Exfoliation with an IPA‐containing emulsion reduced enlarged facial pores and increased the dermis density. IPA, effective mild exfoliator, can be used as a major ingredient for the cosmeceutical skincare products in the future. [ABSTRACT FROM AUTHOR]

Purpose: For prone breast treatment, daily image‐guided radiation therapy (IGRT) allows couch shifting to correct breast position relative to the treatment field. This work investigates the dosimetric effect of reducing kV imaging frequencies and the feasibility of optimizing the frequency using patient anatomy or their first 3‐day shifts. Method: Thirty‐seven prone breast patients who had been treated with skin marker alignment followed by daily kV were retrospectively analyzed. Three IGRT schemes (daily‐kV, weekly‐kV, no‐kV) were simulated, assuming that fractions with kV imaging deliver a dose distribution equivalent to that in computed tomography (CT) planning, whereas other fractions yield a dose distribution as recreated by shifting the CT plan isocenter back to its position before the couch shift was applied. Treatment dose to targets (breast and lumpectomy cavity [LPC]) and organs at risks (OAR)s (heart, ipsilateral lung) in different schemes were calculated. Patient anatomy information on CT plans and first 3‐day couch shift data were analyzed to investigate whether these factors could guide imaging scheme optimization. Results: When kV imaging frequency was reduced, the percentage dose changes (δD) for breast and LPC objectives (average <1%) were smaller than those for heart and lung (average 28%–31% for Dmean). In general, the δD of no‐kV imaging was approximately that of weekly kV imaging × a factor of 1.2–1.4. Although most dose objectives were not affected, the potential higher heart dose may be of concern. No strong correlation was found between δD for different kV frequencies and patient anatomy size/distance or the first 3‐day couch shift data. Conclusions: Despite resulting in lower imaging dose, time, cost, and similar target coverage, a reduction in kV imaging frequency may introduce higher heart complication risk. Daily kVs are needed more in left‐sided breast patients. A less frequent imaging schedule, if considered, cannot be individually optimized using CT anatomic features or early shift data. [ABSTRACT FROM AUTHOR]

Aims The relationship between directly measured body fat and all-cause mortality has been rarely studied. The aim of this study was to evaluate the predictive significance of computed tomography ( CT)-measured body fat, including both visceral fat area ( VFA) and subcutaneous fat area ( SFA), for mortality. Methods The study included 36 656 participants who underwent abdominal CT as part of a health check-up at a single university-affiliated healthcare center in 2007 to 2015. Of those, 32 593 participants with data regarding vital status as of May 2016 were included in the final analysis. The main factors evaluated were VFA, SFA and visceral-to-subcutaneous fat area ratio ( VSR), and the primary outcome was all-cause mortality. Results There were 253 deaths during a mean follow-up of 5.7 years. Increased SFA was associated with decreased all-cause mortality, whereas an increased VFA and VSR were related to increased all-cause mortality. Compared with the predictive power of body mass index ( BMI), SFA and VSR showed a larger area under the curve than did BMI. In Kaplan- Meier survival curve analysis, increased SFA and VSR were associated with decreased and increased hazard of all-cause death, respectively. However, in multivariate Cox proportional hazard regression analysis, only VSR was independently associated with all-cause mortality. Moreover, this relationship was paralleled by the harmful impact of increased VSR on metabolic profiles. Conclusion Increased VSR was an independent predictor of all-cause mortality. This suggests that the location of fat deposits may be more important than the actual amount of body fat. [ABSTRACT FROM AUTHOR]

Developing a material with a new morphology is very important for improving the functional performance and finding new applications. Monoclinic samarium oxysulfate ( Sm2O2SO4) nanoplates were first prepared using a hydrothermal process followed by a post-annealing treatment of an as-synthesized Sm2( OH) 4SO4· 2H2O plate at 450 °C. The fundamental physicochemical properties were examined by scanning electron microscopy, high-resolution transmission electron microscopy, Rietveld X-ray diffraction crystallographic data analysis, thermogravimetric analysis/differential scanning calorimetry, Fourier transform-infrared spectroscopy, Raman spectroscopy, ultraviolet-visible- NIR absorption, and X-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

Purpose: To present the results and discuss potential insights gained through surveys on reference dosimetry practices. Methods: Two surveys were sent to medical physicists to learn about the current state of reference dosimetry practices at radiation oncology clinics worldwide. A short survey designed to maximize response rate was made publicly available and distributed via the AAPM website and a medical physics list server. Another, much more involved survey, was sent to a smaller group of physicists to gain insight on detailed dosimetry practices. The questions were diverse, covering reference dosimetry practices on topics like measurements required for beam quality specification, the actual measurement of absorbed dose and ancillary equipment required like electrometers and environment monitoring measurements. Results: There were 190 respondents to the short survey and seven respondents to the detailed survey. The diversity of responses indicates nonuniformity in reference dosimetry practices and differences in interpretation of reference dosimetry protocols. Conclusions: The results of these surveys offer insight on clinical reference dosimetry practices and will be useful in identifying current and future needs for reference dosimetry. [ABSTRACT FROM AUTHOR]

A display driver IC prototype for mobile full-HD AMOLED display is presented. Since full-HD AMOLED display has too short driving time, conventional R-string DAC column driver cannot obtain enough internal settling time. To solve the problem, therefore, a new R-string DAC column driver architecture is proposed, which has much faster settling time with high accuracy. Also, with the architecture, one 8-bit PTL in conventional R-string DAC is replaced with much smaller two sub-PTLs, decreasing the overall driver area. The measured INL and DNL are 0.49 LSB and 0.38 LSB, respectively. The mean and maximum value of inter-channel DVO is 4.6mV and 7mV, respectively. The proposed linear 10-bit DAC fabricated on 90-nm CMOS process occupies 81% of conventional nonlinear 8-bit R-string DAC area in the same technology. [ABSTRACT FROM AUTHOR]

Review: 143 refs. [ABSTRACT FROM AUTHOR]

Background Few studies have examined the association between the early diastolic mitral inflow velocity/early diastolic mitral annulus velocity ratio (E/e') and chronic kidney disease progression. Methods and Results We reviewed data from 2238 patients with nondialysis chronic kidney disease from the KNOW-CKD (Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease); data from 163 patients were excluded because of missing content. A >50% decrease in estimated glomerular filtration rate from baseline, doubling of serum creatinine, or dialysis initiation and/or kidney transplantation were considered renal events. At baseline, median (interquartile range) ejection fraction and E/e' were 64.0% (60.0%-68.0%) and 9.1 (7.4-11.9), respectively. Proportions of ejection fraction <50% and E/e' ≥15 were 1.3% and 9.6%, respectively. More than one quarter of patients (27.2%) had an estimated glomerular filtration rate <30 mL/min per 1.73 m 2 . During the mean 59.1-month follow-up period, 724 patients (34.9%) experienced renal events. In multivariable Cox proportional hazard regression analysis, the hazard ratio with 95% CI per 1-unit increase in E/e' was 1.027 (1.005-1.050; P =0.016). Penalized spline curve analysis yielded a suggested threshold of E/e' for renal events of 12; in our data set, the proportion of E/e' ≥12 was 4.1%. Conclusions Increased E/e' was associated with an increased hazard of renal events, suggesting that diastolic heart dysfunction is a novel risk factor for chronic kidney disease progression.