Publications by authors named "Kanayama N"
Background/aim: HyperArc (HA) is an automated planning technique enabling single-isocenter brain stereotactic radiotherapy (SRT); however, dosimetric outcomes may be influenced by the planner's expertise. This study aimed to assess the impact of institutional experience on the plan quality of HA-SRT for both single and multiple brain metastases.
Materials And Methods: Twenty patients who underwent HA-SRT for single metastasis between 2020 and 2021 comprised the earlier group, while those treated between 2022 and 2024 constituted the later group.
Brainstem metastases are challenging to manage owing to the critical neurological structures involved. Although stereotactic radiotherapy (SRT) offers targeted high doses while minimizing damage to adjacent normal tissues, the optimal dose fractionation remains undefined. This study evaluated the efficacy and safety of multifraction SRT with an inhomogeneous dose distribution.
View Article and Find Full Text PDFBackground: Fractionated stereotactic radiosurgery (fSRS) is an important treatment strategy for unresected brain metastases. We previously reported that a good volumetric response 6 months after fSRS can be the first step for local control. Few studies have reported the association between gross tumor volume (GTV) dose, volumetric response, and local control in patients treated with the same number of fractions.
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- This study examined the expression of proteins crucial for uterine contractions, comparing tissue samples from 38 PAM patients and 10 controls during cesarean sections.
- Results showed reduced expression of several contraction-associated proteins in PAM tissues, suggesting that inflammation could hinder uterine contractions and contribute to uterine atony, prompting the need for further research on the underlying mechanisms.
Article Synopsis
- The study focused on improving the efficiency of outlining organs at risk (OARs) during intensity-modulated radiation therapy by automating the contouring process using atlas-based auto-segmentation (ABAS).
- Results showed that automation reduced the average time for contour delineation from 57 minutes to 29 minutes, while some OARs still need further geometric accuracy improvements.
- Overall, the ABAS model successfully minimized both work time and software operations, indicating potential for even greater efficiency with enhancements to contour accuracy.
Purpose: The study aimed to investigate the optimal isodose line (IDL) in linear accelerator-based stereotactic radiotherapy for single brain metastasis, using HyperArc. We compared the dosimetric parameters for target and normal brain tissue among six plans with different IDLs.
Methods: This study included 30 patients with single brain metastasis.
Article Synopsis
- Amniotic fluid embolism (AFE) is a serious condition that can cause respiratory and circulatory failure during pregnancy, complicating treatment with issues like bleeding tendencies due to disseminated intravascular coagulation (DIC).
- A 39-year-old patient with AFE underwent emergency cesarean section and required massive blood transfusions; when she developed critical respiratory and circulatory failure, venoarterial extracorporeal membrane oxygenation (VA-ECMO) was implemented without initial anticoagulation.
- The patient's condition stabilized after five days on VA-ECMO, allowing her to be weaned off the machine and ultimately discharged home in good health, highlighting the importance of managing bleeding tendencies effectively in such cases.
Article Synopsis
- The study aimed to evaluate the safety of long-term use of ritodrine hydrochloride, a tocolytic agent used in Japan for treating threatened preterm labor, particularly its link to maternal deaths.
- It analyzed data from 390 maternal death cases from 2010 to 2020, revealing that 32 involved the administration of ritodrine, with specific doses and routes documented.
- The findings indicated higher instances of serious health issues like perinatal cardiomyopathy and pulmonary edema in patients who received ritodrine, suggesting a potential risk associated with its long-term use during pregnancy.
Article Synopsis
- * A case study describes a 42-year-old woman experiencing urgent cesarean delivery due to abnormal fetal heart rates, where signs of coagulopathy were present before she exhibited breathing difficulties or low blood pressure.
- * The findings suggest that monitoring for AFE-related coagulopathy should be initiated earlier, especially when there are changes in fetal heart patterns and uterine activity, to improve patient outcomes.
Postoperative radiotherapy for breast cancer reportedly increases the risk of thoracic soft tissue sarcomas, particularly angiosarcomas; however, the risk in the Japanese population remains unknown. Therefore, this study aimed to investigate the incidence of thoracic soft tissue sarcoma among patients with breast cancer in Japan and determine its association with radiotherapy. This retrospective cohort study used data from the population-based cancer registry of the Osaka Prefecture.
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- The study investigates how the distance between the CBCT isocenter and the brain center (DBI) affects image quality in stereotactic irradiation for brain metastasis.
- Using both a phantom study and a patient study, researchers found that greater distances resulted in poorer image quality, particularly in objective measures like contrast-to-noise ratio and artifact levels.
- The findings suggest that aligning the CBCT isocenter with the brain center can enhance image quality and improve patient treatment outcomes.
Article Synopsis
- Amniotic fluid embolism (AFE) and placental abruption (PA) are pregnancy-related conditions linked to severe blood clotting issues known as disseminated intravascular coagulation (DIC).
- AFE tends to have more pronounced fibrinolysis compared to PA and may activate a different mechanism for the fibrinolytic process.
- In a study comparing various coagulation factors in patients with AFE, severe PA, and healthy controls, results showed increased levels of certain markers in both AFE and severe PA, but AFE also exhibited significant changes in specific agents associated with enhanced fibrin breakdown.
Background: The aim of this study was to evaluate the effectiveness of intensity-modulated radiation therapy in combination with long-term androgen deprivation therapy for high-risk and very high-risk localized prostate cancer while also investigating factors associated with the therapeutic effect.
Methods: Men who fulfilled criteria for the National Comprehensive Cancer Network high-risk or very high-risk localized prostate cancer and were treated with definitive intensity-modulated radiation therapy (74-78 Gy) of the prostate and the seminal vesicle combined with androgen deprivation therapy in our institution from 2007 to 2016 were identified (n = 197). In principle, patients received androgen deprivation therapy for 3-6 months before radiation, concurrently, and for 2 years after completion of intensity-modulated radiation therapy.
The involvement of the human amygdala in facial mimicry remains a matter of debate. We investigated neural activity in the human amygdala during a task in which an imitation task was separated in time from an observation task involving facial expressions. Neural activity in the amygdala was measured using functional magnetic resonance imaging in 18 healthy individuals and using intracranial electroencephalogram in six medically refractory patients with epilepsy.
View Article and Find Full Text PDFIndependent component analysis (ICA) is widely used today for scalp-recorded EEG analysis. One of the limitations of ICA-based analysis is polarity indeterminacy. It is not easy to find detailed documentations that explains engineering solutions of how the polarity indeterminacy is addressed in a given implementation.
View Article and Find Full Text PDFTo explore predictors of the histopathological response to preoperative chemoradiotherapy (CRT) in patients with pancreatic cancer (PC) using dual-energy computed tomography-reconstructed images. This retrospective study divided 40 patients who had undergone preoperative CRT (50-60 Gy in 25 fractions) followed by surgical resection into two groups: the response group (Grades II, III and IV, evaluated from surgical specimens) and the nonresponse group (Grades Ia and Ib). The computed tomography number [in Hounsfield units (HUs)] and iodine concentration (IC) were measured at the locations of the aorta, PC and pancreatic parenchyma (PP) in the contrast-enhanced 4D dual-energy computed tomography images.
View Article and Find Full Text PDFIntroduction: With category II fetal heart rate tracings, the preferred timing of interventions to prevent fetal hypoxic brain damage while limiting operative interventions remains unclear. We aimed to estimate fetal extracellular base deficit (BD ) during labor with category II tracings to quantify the timing of potential interventions to prevent severe fetal metabolic acidemia.
Material And Methods: A longitudinal study was conducted using the database of the Recurrence Prevention Committee, Japan Obstetric Compensation System for Cerebral Palsy, including infants with severe cerebral palsy born at ≥34 weeks' gestation between 2009 and 2014.
Purpose: The geometric distortion related to magnetic resonance (MR) imaging in a diagnostic radiology (MR) and radiotherapy (MR) setup is evaluated, and the dosimetric impact of MR distortion on fractionated stereotactic radiotherapy (FSRT) in patients with brain metastases is simulated.
Materials And Methods: An anthropomorphic skull phantom was scanned using a 1.5‑T MR scanner, and the magnitude of MR distortion was calculated with (MR-DC and MR-DC) and without (MR-nDC and MR-nDC) distortion-correction algorithms.
The sex of the conceived child is a significant concern for parents. To verify whether there women have pregnancy bias toward boys or girls, we investigated whether the history of continuous same-sex pregnancy was associated with the subsequent child's sex. We prospectively analyzed data from the Japan Environment and Children's Study, a birth cohort study.
View Article and Find Full Text PDFThis study aimed to compare dosimetric parameters for targets and organs at risk (OARs) between volumetric modulated arc therapy (VMAT) and automated VMAT (HyperArc, HA) plans in stereotactic radiotherapy for patients with cervical metastatic spine tumors. VMAT plans were generated for 11 metastases using the simultaneous integrated boost technique to deliver 35 to 40 and 20 to 25 Gy for high dose and elective dose planning target volume (PTVHD and PTVED), respectively. The HA plans were retrospectively generated using 1 coplanar and 2 noncoplanar arcs.
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- - The study focuses on the immediate side effects from stereotactic radiotherapy (SRT) for brain metastases, analyzing data from 315 patients treated between May 2019 and February 2022.
- - Out of 439 SRT sessions, only 3.6% of patients experienced significant side effects (Grade ≥ 2), with serious complications (Grade ≥ 3) found in just 1.6% of cases.
- - Findings suggest that while SRT is generally safe, particularly for patients with multiple and large lesions, close monitoring for complications is still essential post-treatment.
Article Synopsis
- This study compares different techniques of volumetric modulated arc therapy (VMAT) for treating patients with two brain metastases, focusing on single-isocentric (SIC) and multi-isocentric (MIC) plans.
- The researchers conducted a retrospective analysis on 58 patients, assessing how these plans handle rotational errors during treatment, particularly regarding the distances from the tumor surface.
- Results indicated that MIC plans better spare surrounding brain tissue for larger tumor surface distances (TSD > 6.6 cm), while SIC plans excelled in conformity for smaller TSD, highlighting the strengths of each technique based on specific clinical scenarios.
Immunohistochemical analysis of formalin-fixed paraffin-embedded (FFPE) tissue blocks is routinely used to identify virus-infected cells. However, detecting virus particles in FFPE sections using light microscopy is difficult because of the light diffraction resolution limitations of an optical microscope. In this study, light microscopy and field emission scanning electron microscopy were performed to observe 3-dimensional virus particles in FFPE sections in a nondestructive manner using NanoSuit or osmium conductive treatment methods.
View Article and Find Full Text PDFTo compare dosimetric parameters for the hippocampus, organs at risk (OARs), and targets of volumetric modulated arc therapy (VMAT), noncoplanar VMAT (NC-VMAT), and HyperArc (HA) plans in patients undergoing postoperative radiotherapy for primary brain tumors. For 20 patients, HA plans were generated to deliver 40.05 to 60 Gy for the planning target volume (PTV).
View Article and Find Full Text PDFBackground/aim: Dosimetric parameters in volumetric modulated arc therapy (VMAT), non-coplanar VMAT (NC-VMAT), and automated NC-VMAT (HyperArc, HA) were compared for patients with maxillary sinus carcinoma (MSC).
Patients And Methods: Twenty HA plans were generated to deliver 70.4, 64, and 46 Gy for planning target volumes with high (PTV1), intermediate (PTV2), and low risk (PTV3), respectively.