Surgical productivity recovery after the COVID-19 pandemic in Japan.

Introduction: Previous studies demonstrated that the surgical productivity regressed in 2020. This study therefore explored whether the COVID-19 pandemic had any significant lasting effect of reducing the surgical productivity in Japan. This is a retrospective observational study which is an extension of the previous ones. Methods: The authors analyzed 18,805 surgical procedures performed during the study period from April 1 through September 30 in 2016-22. A non-radial and non-oriented Malmquist model under the variable returns-to-scale assumptions was employed. The decision-making unit (DMU) was defined as a surgical specialty department. Inputs were defined as (1) the number of assistants, and (2) the surgical duration. The output was defined as the surgical fee. The study period was divided into 42 one-month periods. The authors added all the inputs and outputs for each DMU during these study periods, and computed its Malmquist index, efficiency change and technical change. The outcome measures were its annual productivity, efficiency, and technical changes between the same months in each year. Results: There was no statistically significant difference in annual productivity, efficiency, and technical changes between pre-pandemic and post-pandemic periods. Discussion: No evidence was found to suggest that the COVID-19 pandemic has any significant lasting effect of reducing the surgical productivity.

Behavior of intracellular lipid droplets during cell division in HuH7 hepatoma cells.

Intracellular lipid droplets (LDs) are ubiquitous organelles found in many cell types. During mitosis, membranous organelles, including mitochondria, are divided into small pieces and transferred to daughter cells; however, the process of LD transfer to daughter cells is not fully elucidated. Herein, we investigated the behavior of LDs during mitosis in HuH7 human hepatoma cells. While fragments of the Golgi apparatus were scattered in the cytosol during mitosis, intracellular LDs retained their size and spherical morphology as they translocated to the two daughter cells. LDs were initially distributed throughout the cell during prophase but positioned outside the spindle in metaphase, aligning at the far sides of the centrioles. A similar distribution of LDs during mitosis was observed in another hepatocarcinoma HepG2 cells. When the spindle was disrupted by nocodazole treatment or never in mitosis gene A-related kinase 2A knockdown, LDs were localized in the area outside the chromosomes, suggesting that spindle formation is not necessary for LD localization at metaphase. The amount of major LD protein perilipin 2 reduced while LDs were enriched in perilipin 3 during mitosis, indicating the potential alteration of LD protein composition. Conclusively, the behavior of LDs during mitosis is distinct from that of other organelles in hepatocytes.

Fact-finding survey on the competencies and literacy of radiological technologists regarding radiation disasters.

BACKGROUND: Radiological technologists serve as risk communicators who aim to lessen patients' anxiety about radiation exposure, in addition to performing radiological examinations. OBJECTIVE: We conducted a fact-finding survey on knowledge and awareness of radiation disasters among the radiological technologists to reveal their literacy and competencies regarding radiation disasters. METHODS: A paper questionnaire was distributed to 1,835 radiological technologists at 166 National Hospital Organization facilities in Japan. The 28-item questionnaire covered knowledge and awareness of radiation protection and radiation disasters. Radiological technologists were divided into 2 groups by regionality: areas where a nuclear power station was present/nearby (NPS areas) and non-NPS areas. RESULTS: Completed questionnaires were returned from 148 facilities with a facility response rate of 89.2% and from 1,391 radiological technologists with a response rate of 75.8%. There were 1,290 valid responses with a valid response rate of 70.3%. The correct answer rate for knowledge of radiation protection and radiation disasters was high in the 24 NPS areas. There were no differences in awareness of radiation disasters between NPS and non-NPS areas. CONCLUSIONS: Establishing a nationwide, region-independent training system can be expected to improve literacy regarding radiation disasters among radiological technologists. Willingness to assist during disasters was high among radiological technologists irrespective of area, indicating that the competencies of radiological technologists represent a competency model for radiation disaster assistance.

Effect of surgeon experience on technical efficiency.

Surgeon experience certainly improves their technical efficiency although it also causes physiological changes with aging. The authors hypothesized that surgeons' technical efficiency improves with increasing experience up to a point where it then decreases, which is a concave relationship. The authors collected data from all the surgical procedures performed at University Hospital from April through September in 2013-19. The dependent variable was defined as surgeons' technical efficiency scores that were calculated using output-oriented Charnes-Cooper-Rhodes model of data envelopment analysis. Inputs were defined as (1) the number of assistants and (2) the duration of surgical operation. The output was defined as the surgical fee for each surgery. Surgeon experience was defined as the number of years since medical school graduation. Five control variables were selected: surgical volume, gender, academic rank, surgical specialty, and the year of surgery. Multiple regression analysis using pooled and random-effects Tobit models was performed for our panel data. Totally 20,375 surgical procedures performed by 264 surgeons in 42 months were analyzed. The coefficients of experience and the square of experience were not significantly different from zero. The other coefficients were also insignificant. Surgeons' technical efficiency does not have a concave relationship with experience.

High-Density Lipoprotein Suppresses Neutrophil Extracellular Traps Enhanced by Oxidized Low-Density Lipoprotein or Oxidized Phospholipids.

Neutrophil extracellular traps (NETs) are found in patients with various diseases, including cardiovascular diseases. We previously reported that copper-oxidized low-density lipoprotein (oxLDL) promotes NET formation of neutrophils, and that the resulting NETs increase the inflammatory responses of endothelial cells. In this study, we investigated the effects of high-density lipoproteins (HDL) on NET formation. HL-60-derived neutrophils were treated with phorbol 12-myristate 13-acetate (PMA) and further incubated with oxLDL and various concentrations of HDL for 2 h. NET formation was evaluated by quantifying extracellular DNA and myeloperoxidase. We found that the addition of native HDL partially decreased NET formation of neutrophils induced by oxLDL. This effect of HDL was lost when HDL was oxidized. We showed that oxidized phosphatidylcholines and lysophosphatidylcholine, which are generated in oxLDL, promoted NET formation of PMA-primed neutrophils, and NET formation by these products was completely blocked by native HDL. Furthermore, we found that an electronegative subfraction of LDL, LDL(-), which is separated from human plasma and is thought to be an in vivo oxLDL, was capable of promoting NET formation. These results suggest that plasma lipoproteins and their oxidative modifications play multiple roles in promoting NET formation, and that HDL acts as a suppressor of this response.

Patients' acceptance of placebo antibiotics in Japan: a prescription for antimicrobial resistance.

BACKGROUND: The generalized use of antibiotics has led to the emergence of bacteria which are resistant to antimicrobial agents. This stems in part from the patient's tendencies to seek antibiotics for diseases when not necessary. Hence, this article investigated patient acceptance of prescribing placebos as a substitute for unnecessary antibiotics in Japan, where physicians are under severe time constraints and are unable to offer explanations and persuade patients who demand unnecessary antibiotics prescription. METHODS: A web-based questionnaire was administered to assess patients' acceptance of the placebo treatment under informed consent. One thousand participants representing all genders and age-class were randomly selected from the online panel of a web-survey company. RESULTS: The results showed that 67.9% of the participants were "satisfied" to receive such treatments, whereas 20.6% indicated acceptance of the prescription but without satisfaction. In total, 88.5% of the participants accepted the prescription of placebo, a result consistent with that of a preceding study on placebo treatments conducted in the United States. In the survey, tone of persuasion did not affect the patients' attitudes; however, patients who were loyal to their physicians exhibited lower refusal rates. CONCLUSION: The survey results showed that the prescription of "ethical placebos" could be an acceptable option for the patients in Japan. For ethical concerns, an additional literature survey was conducted and the result suggested that such a radical treatment option could be justified, provided that the prescription benefits patients and informed consent is properly obtained. Albeit it is impractical to use, because of ethical and operational concerns, it would be worth further investigation to ensure diversity in the countermeasures for antimicrobial resistance, a major public health threat nowadays.

Productivity Change of Surgeons During the Coronavirus Disease 2019 Pandemic in Japan.

The purpose of this study is to compute surgical total factor productivity before and during the pandemic with Malmquist index, and to evaluate the effect of coronavirus disease 2019 (COVID-19) on its productivity change. The COVID-19 pandemic has significantly shifted healthcare resources allocation; more healthcare resources have focused on measures against the COVID-19 pandemic. The authors collected data from all the surgical procedures performed in Teikyo University Hospital from April 1 through September 30 in 2019 and in 2020. Non-radial and non-oriented Malmquist model under the constant return-to-scale assumptions was employed. The decision-making unit was defined as a surgeon with the highest academic rank in surgery. Inputs were defined as (1) the number of medical doctors who assisted surgery and (2) the duration of surgical operation from skin incision to closure. The output was defined as the surgical fee for each surgery. The study period was divided into four 3-month periods. We added all the inputs and outputs of the surgical procedures for each decision-making unit during these study periods, and computed his/her Malmquist index, efficiency change, and technical change. Four thousand six hundred and two surgical procedures performed by 75 surgeons were analyzed. The productivity progressed significantly during 2019 (P = .008) while the productivity changes in 2020 were not significantly different from 0. On year-on-year comparisons, the productivity change was not significantly different from 0. The COVID-19 pandemic had a negative impact on the productivity progress of surgery that was unrelated to its countermeasures.

Surgical productivity did not suffer despite the states of emergency against the COVID-19 pandemic in Japan: a retrospective observational study.

BACKGROUND: The purpose of this study is to compute surgical total factor productivity with Malmquist index, and to evaluate the effects of states of emergency against the novel coronavirus disease 2019 (COVID-19) pandemic on its productivity change. We hypothesized that the states of emergency significantly reduced surgical total factor productivity in Japan. METHODS: The authors collected data from all the surgical procedures performed in Teikyo University Hospital from April 1 through September 30 in 2019-21. Non-radial and non-oriented Malmquist model under the variable returns-to-scale assumptions was employed. The decision making unit (DMU) was defined as a surgical specialty department. Inputs were defined as (1) the number of medical doctors who assisted surgery, and (2) the duration of surgical operation from skin incision to closure. The output was defined as the surgical fee for each surgery. The study period was divided into fifty-one ten- (or eleven-) day periods. We added all the inputs and outputs of the surgical procedures for each DMU during these study periods, and computed its Malmquist index, efficiency change and technical change. RESULTS: Seven thousand nine hundred and thirty-one surgical procedures were analyzed. The overall productivity and efficiency progressed significantly both during states of emergency and during no states of emergency. Our subgroup analysis demonstrated that there were no surgical specialties that had significantly different productivity, efficiency or technical changes between states of emergency and no states of emergency. CONCLUSIONS: We demonstrated that the surgical productivity did not suffer despite the states of emergency against the COVID-19 pandemic in Japan.

Sar1 Affects the Localization of Perilipin 2 to Lipid Droplets.

Lipid droplets (LDs) are intracellular organelles that are ubiquitous in many types of cells. The LD core consists of triacylglycerols (TGs) surrounded by a phospholipid monolayer and surface proteins such as perilipin 2 (PLIN2). Although TGs accumulate in the phospholipid bilayer of the endoplasmic reticulum (ER) and subsequently nascent LDs buds from ER, the mechanism by which LD proteins are transported to LD particles is not fully understood. Sar1 is a GTPase known as a regulator of coat protein complex Ⅱ (COPⅡ) vesicle budding, and its role in LD formation was investigated in this study. HuH7 human hepatoma cells were infected with adenoviral particles containing genes coding GFP fused with wild-type Sar1 (Sar1 WT) or a GTPase mutant form (Sar1 H79G). When HuH7 cells were treated with oleic acid, Sar1 WT formed a ring-like structure around the LDs. The transient expression of Sar1 did not significantly alter the levels of TG and PLIN2 in the cells. However, the localization of PLIN2 to the LDs decreased in the cells expressing Sar1 H79G. Furthermore, the effects of Sar1 on PLIN2 localization to the LDs were verified by the suppression of endogenous Sar1 using the short hairpin RNA technique. In conclusion, it was found that Sar1 has some roles in the intracellular distribution of PLIN2 to LDs in liver cells.

Sesamin and Hepatic Metabolites Derived from Sesamin and Episesamin Antagonize Farnesoid X Receptor and Reduce the Expression of Gluconeogenesis-Related Genes.

Sesamin and episesamin are the main lignans found in refined sesame oil and have been reported to exert various health benefits. However, the health benefits of these lignans and their molecular mechanisms have not been fully understood. This study evaluated the effects of sesamin, episesamin, and their metabolites on the nuclear bile acid receptor, farnesoid X receptor (FXR, NR1H4), which regulate gene expression involved in bile acid metabolism and gluconeogenesis. By using two different cell-based luciferase reporter assay systems, we found that sesamin, sesamin metabolites, and some episesamin metabolites inhibited FXR activation driven by a bile acid and a synthesized agonist, and it is suggested that these compounds exert their antagonist activity by competing with the FXR agonists on the ligand-binding domain. Sesamin and its major metabolite SC-1 suppressed the expression of several gluconeogenesis-related genes governed by FXR in HepG2 cells but did not affect the expression level of CYP7A1, the rate-limiting enzyme for bile acid synthesis. Dietary sesamin supplementation (AIN-93G supplemented with 0.5% sesamin) led to the decreased hepatic expression of several gluconeogenesis-related genes and reduced blood glucose levels in mice, without adverse effects on bile acid metabolism. These results shed light on the health benefits of taking sesamin and episesamin.

Injection of hydrogel spacer increased maximal intrafractional prostate motion in anterior and superior directions during volumetric modulated arc therapy-stereotactic body radiation therapy for prostate cancer.

BACKGROUND: The aim of this study was to clarify the association between intrafractional prostate shift and hydrogel spacer. METHODS: Thirty-eight patients who received definitive volumetric modulated arc therapy (VMAT)-stereotactic body radiation therapy (SBRT) for prostate cancer with prostate motion monitoring in our institution in 2018-2019 were retrospectively evaluated. In order to move the rectum away from the prostate, hydrogel spacer (SpaceOAR system, Boston Scientific, Marlborough, the United States) injection was proposed to the patients as an option in case of meeting the indication of use. We monitored intrafractional prostate motion by using a 4-dimensional (4D) transperineal ultrasound device: the Clarity 4D ultrasound system (Elekta AB). The deviation of the prostate was monitored in each direction: superior-inferior, left-right, and anterior-posterior. We also calculated the vector length. The maximum intrafractional displacement (MID) per fraction for each direction was detected and mean of MIDs was calculated per patient. The MIDs in the non-spacer group and the spacer group were compared using the unpaired t-test. RESULTS: We reviewed 33 fractions in eight patients as the spacer group and 148 fractions in 30 patients as the non-spacer group. The superior MID was 0.47 ± 0.07 (mean ± SE) mm versus 0.97 ± 0.24 mm (P = 0.014), the inferior MID was 1.07 ± 0.11 mm versus 1.03 ± 0.25 mm (P = 0.88), the left MID was 0.74 ± 0.08 mm versus 0.87 ± 0.27 mm (P = 0.55), the right MID was 0.67 ± 0.08 mm versus 0.92 ± 0.21 mm (P = 0.17), the anterior MID was 0.45 ± 0.06 mm versus 1.16 ± 0.35 mm (P = 0.0023), and the posterior MID was 1.57 ± 0.17 mm versus 1.37 ± 0.22 mm (P = 0.56) in the non-spacer group and the spacer group, respectively. The max of VL was 2.24 ± 0.19 mm versus 2.89 ± 0.62 mm (P = 0.19), respectively. CONCLUSIONS: Our findings suggest that maximum intrafractional prostate motion during VMAT-SBRT was larger in patients with hydrogel spacer injection in the superior and anterior directions. Since this difference seemed not to disturb the dosimetric advantage of the hydrogel spacer, we do not recommend routine avoidance of the hydrogel spacer use.

Equality of Surgical Fee Schedule in Japan: A Retrospective Observational Study.

The authors had previously demonstrated that the Japanese surgical fee schedule had been unequal among surgical specialties in spite of its biannual revisions. This study examined how the degree of inequality of the fee schedule changed by estimating Gini coefficients for efficiency scores computed from data envelopment analysis. All the surgeries at Teikyo University Hospital in 2013 to 2018 were candidates used for the analysis of efficiency and equality of fee schedule. Inputs were defined as (1) the number of assistants, and (2) the duration of operation. An output was defined as the surgical fee. Each surgeon's efficiency score was calculated using data envelopment analysis. Using the medians of efficiency scores in each surgical specialty, the authors inferred Gini coefficients and their standard errors in each year and in each surgical fee schedule. The authors analyzed 16 307 surgical procedures during the study period of 2013 to 2018. There was no statistically significant difference in the Gini coefficients between the years and between the surgical fee schedules (P > .05). It was demonstrated that the degree of inequality of the Japanese surgical fee schedule remained constant from 2013 through 2018.

Insulin-induced genes INSIG1 and INSIG2 mediate oxysterol-dependent activation of the PERK-eIF2α-ATF4 axis.

Insulin-induced genes (INSIGs) encode endoplasmic reticulum-resident proteins that regulate intracellular cholesterol metabolism. Oxysterols are oxygenated derivatives of cholesterol, some of which orchestrate lipid metabolism via interaction with INSIGs. Recently, it was reported that expression of activating transcription factor-4 (ATF4) was induced by certain oxysterols; the precise of mechanism is unclear. Herein, we show that INSIGs mediate ATF4 upregulation upon interaction with oxysterol. Oxysterols that possess a high affinity for INSIG, such as 27- and 25-hydroxycholesterol (25HC), markedly induced the increase of ATF4 protein when compared with other oxysterols. In addition, ATF4 upregulation by these oxysterols was attenuated in INSIG1/2-deficient Chinese hamster ovary cells and recovered by either INSIG1 or INSIG2 rescue. Mechanistic studies revealed that the binding of 25HC to INSIG is critical for increased ATF4 protein via activation of protein kinase RNA-activated-like ER kinase and eukaryotic translation initiation factor 2α. Knockout of INSIG1 or INSIG2 in human hepatoma Huh7 cells attenuated ATF4 protein upregulation, indicating that only one of the endogenous INSIGs, unlike overexpression of intrinsic INSIG1 or INSIG2, was insufficient for ATF4 induction. Furthermore, ATF4 proactively upregulated the cell death-inducible gene expression, such as Chop, Chac1, and Trb3, thereby markedly reducing cell viability with 25HC. These findings support a model whereby that INSIGs sense an increase in oxysterol in the endoplasmic reticulum and induce an increase of ATF4 protein via the protein kinase RNA-activated-like ER kinase-eukaryotic translation initiation factor 2α pathway, thereby promoting cell death.

Do technically efficient surgeons continue to provide active clinical services in a university hospital?

It is difficult for university hospitals to recruit and retain technically efficient surgeons because their missions include teaching and research as well as clinical services. The authors hypothesized that technically efficient surgeons do not continue to provide active clinical services in a university hospital. The authors collected data from all the surgical procedures performed at Teikyo University Hospital from April 1 through September 30 in 2013-2018. The dependent variable was defined as a length of each surgeon's active clinical services measured by month. Data envelopment analysis was employed to calculate each surgeon's technical efficiency score. Five control variables were selected; experience, medical school, surgical volume, gender, and academic ranks. Multiple regression analysis was performed. Efficiency scores had significantly negative association with length of active clinical services. Experience and surgical volume had significantly positive association with length of active clinical services. The other coefficients of control variables were insignificant. Technically efficient surgeons provide shorter active clinical services in a university hospital.

[Multicenter Evaluation of Cine Angiography and Digital Subtraction Angiography Dose Rate for Various Angiography Programs: Comparison with Fluoroscopic Dose Rate].

We conducted a nationwide multicenter survey of various interventional radiology (IVR) procedures. Data were collected from 385 X-ray systems in 126 institutions, including 432 cine programs and 380 digital subtraction angiography (DSA) programs for diagnostic catheterization, percutaneous coronary intervention (PCI), ablation, transcatheter aortic valve implantation (TAVI), neurologic IVR, thorax IVR, abdominal IVR, and endovascular therapy (EVT). Fluoroscopic and cine dose rates were 10.1 mGy/min and 110.7 mGy/min, respectively, whereas for DSA programs, the median fluoroscopic and DSA dose rates were 8.0 mGy/min and 224.8 mGy/min, respectively. The DSA dose rate was more than twice the cine dose rate. The largest difference between dose rates was for diagnostic catheterization, which had a cine dose rate of 142.6 mGy/min and a fluoroscopic dose rate of 12.6 mGy/min (by a factor of 12.5), followed by EVT, which had a DSA dose rate of 216.0 mGy/min and a fluoroscopic dose rate of 7.7 mGy/min (by a factor of 29.6). The smallest difference between dose rates was for TAVI, which had a cine dose rate of 96.8 mGy/min and a fluoroscopic dose rate of 12.0 mGy/min (by a factor of 8.9), followed by neurologic IVR, which had a DSA dose rate of 227.9 mGy/min and a fluoroscopic dose rate of 9.6 mGy/min (by a factor of 22.6). Compared with the fluoroscopic dose rates, the cine dose rates were 9-13 times higher and the DSA dose rates were 22-30 times higher; the DSA dose rates were more than double the cine dose rates.

Muscle-specific TGR5 overexpression improves glucose clearance in glucose-intolerant mice.

TGR5, a G protein-coupled bile acid receptor, is expressed in various tissues and regulates several physiological processes. In the skeletal muscle, TGR5 activation is known to induce muscle hypertrophy; however, the effects on glucose and lipid metabolism are not well understood, despite the fact that the skeletal muscle plays a major role in energy metabolism. Here, we demonstrate that skeletal muscle-specific TGR5 transgenic (Tg) mice exhibit increased glucose utilization, without altering the expression of major genes related to glucose and lipid metabolism. Metabolite profiling analysis by capillary electrophoresis time-of-flight mass spectrometry showed that glycolytic flux was activated in the skeletal muscle of Tg mice, leading to an increase in glucose utilization. Upon long-term, high-fat diet challenge, blood glucose clearance was improved in Tg mice without an accompanying increase in insulin sensitivity in skeletal muscle and a reduction of body weight. Moreover, Tg mice showed improved age-associated glucose intolerance. These results strongly suggest that TGR5 ameliorated glucose metabolism disorder that is caused by diet-induced obesity and aging by enhancing the glucose metabolic capacity of the skeletal muscle. Our study demonstrates that TGR5 activation in the skeletal muscle is effective in improving glucose metabolism and may be beneficial in developing a novel strategy for the prevention or treatment of hyperglycemia.

Surface and build-up dose comparison between Elekta 6 MV flattening filter and flattening-filter-free beams using an advanced Markus ionization chamber and a solid water-equivalent phantom.

Using a plane-parallel advanced Markus ionization chamber and a stack of water-equivalent solid phantom blocks, percentage surface and build-up doses of Elekta 6 MV flattening filter (FF) and flattening-filter-free (FFF) beams were measured as a function of the phantom depth for field sizes ranging from 2 × 2 to 10 × 10 cm2 . It was found that the dose difference between the FF and the FFF beams was relatively small. The maximum dose difference between the FF and the FFF beams was 4.4% at a depth of 1 mm for a field size of 2 × 2 cm2 . The dose difference was gradually decreased while the field size was increased up to 10 × 10 cm2 . The measured data were also compared to published Varian FF and FFF data, suggesting that the percentage surface and build-up doses as well as the percentage dose difference between FF and FFF beams by our Elekta linac were smaller than those by the Varian linac.

[Multicenter Survey on Radiation Dose of Cardiac Intervention].

We conducted a nationwide survey of multiple institutions and collected data of various interventional procedures in the field of cardiology. Included in the analysis were 126 institutions, 381 X-ray systems, and 805 protocols. The dose values were compared with the Japanese diagnostic reference levels (DRLs) 2015. Fluoroscopy time, air kerma at the patient entrance reference point (Ka, r), and air kerma-area product (PKA ) were analyzed for various interventional procedures in 5,734 cardiology patients. The fluoroscopic dose rate (FDR) for pulmonary vein isolation (PVI) was less than half that of the 75th percentile of the Japanese DRLs 2015. The 75th percentiles of fluoroscopy time, Ka, r, and PKA for the respective interventional procedures were as follows: 11.0 min, 735 mGy, and 64 Gyï½¥cm2 for diagnostic coronary angiography (CA); 13.2 min, 839 mGy, and 75 Gyï½¥cm2 for CA + left ventriculography; 34.4 min, 1,810 mGy, and 148 Gyï½¥cm2 for percutaneous coronary intervention (PCI) excluding chronic total occlusion; 80.1 min, 4,338 mGy, and 312 Gyï½¥cm2 for PCI for chronic total occlusion; 74.4 min, 833 mGy, and 90 Gyï½¥cm2 for PVI; and 34.0 min, 795 mGy, and 94 Gyï½¥cm2 for transcatheter aortic valve implantation, respectively. In assessing dose values in interventional radiology, the difficulty of the technique needs to be considered, and the DRL values for FDR, fluoroscopic time, Ka, r, and PKA for each interventional procedure are considered necessary when reassessing or updating DRLs.

Retrospective dose reconstruction of prostate stereotactic body radiotherapy using cone-beam CT and a log file during VMAT delivery with flattening-filter-free mode.

This study aimed to reconstruct the dose distribution of single fraction of stereotactic body radiotherapy for patients with prostate cancer using cone-beam computed tomography (CBCT) and a log file during volumetric-modulated arc therapy (VMAT) delivery with flattening-filter-free (FFF) mode. Twenty patients with clinically localized prostate cancer were treated with FFF-VMAT, and projection images for in-treatment CBCT (iCBCT) imaging were concomitantly acquired with a log file. A D95 dose of 36.25 Gy in five fractions was prescribed to each planning target volume (PTV) on each treatment planning CT (pCT). Deformed pCT (dCT) was obtained from the iCBCT using a hybrid deformable image registration algorithm. Dose distributions on the dCT were calculated using Pinnacle3 v9.10 by converting the log file data to Pinnacle3 data format using an in-house software. Dose warping was performed by referring to deformation vector fields calculated from pCT and dCT. Reconstructed dose distribution was compared with that of the original plan. Dose differences between the original and reconstructed dose distributions were within 3% at the isocenter and observed in PTV and organ-at-risk (OAR) regions. Differences in OAR regions were relatively larger than those in the PTV, presumably because OARs were more deformed than the PTV. Therefore, our method can be used successfully to reconstruct the dose distributions of one fraction using iCBCT and a log file during FFF-VMAT delivery.

How efficient are surgical treatments in Japan? The case of a high-volume Japanese hospital.

Japan's healthcare expenditures, which are largely publicly funded, have been growing dramatically due to the rapid aging of the population as well as the innovation and diffusion of new medical technologies. Annual costs for surgical treatments are estimated to be approximately USD 20 billion. Using unique longitudinal clinical data at the individual surgeon level, this study aims to estimate the technical efficiency of surgical treatments across surgical specialties in a high-volume Japanese teaching hospital by employing stochastic frontier analysis (SFA) with production frontier models. We simultaneously examine the impacts of potential determinants that are likely to affect inefficiency in operating rooms. Our empirical results show a relatively high average technical efficiency of surgical production, with modest disparity across surgical specialties. We also demonstrate that an increase in the number of operations performed by a surgeon significantly reduces operating room inefficiency, whereas the revision of the fee-for-service schedule for surgical treatments does not have a significant impact on inefficiency. In addition, we find higher technical efficiency among surgeons who perform multiple daily surgeries than those who perform a single operation in a day. We suggest that it is important for hospital management to retain efficient surgeons and physicians and provide efficient healthcare services given the competitive Japanese healthcare market.