Evaluation of raw-data-based and calculated electron density for contrast media with a dual-energy CT technique.

Objectives: The aim of the current study is to evaluate the accuracy and the precision of raw-data-based relative electron density (RED) and the calibration-based RED (RED) at a range of low-RED to high-RED for tissue-equivalent phantom materials by comparing them with reference RED (RED) and to present the difference of RED and RED for the contrast medium using dual-energy CT (DECT).

Methods: The RED images were reconstructed by raw-data-based decomposition using DECT. For evaluation of the accuracy of the RED, RED was calculated for the tissue-equivalent phantom materials based on their specified density and elemental composition.

Metal artifact reduction techniques for single energy CT and dual-energy CT with various metal materials.

Objective: The aim of the current study is to evaluate the effectiveness of reduction metal artifacts using kV-CT image with the single-energy based metal artefact reduction (SEMAR) technique by single-energy reconstruction, monochromatic CT and rED reconstructed by dual-energy reconstruction.

Methods: Seven different metal materials (brass, aluminum, copper, stainless, steel, lead and titanium) were placed inside the water-based PMMA phantom. After DECT-based scan, the artefact index (AI) were evaluated with the kV-CT images with and without SEMAR by single-energy reconstruction, and raw-data based electron density (rED), monochromatic CT images by dual-energy reconstruction.

Concurrent chemoradiotherapy for locally advanced squamous cell carcinoma of the cervix in a uterus didelphys with vaginal septum.

In November 2011, a 61-year-old woman was diagnosed with squamous cell carcinoma (SCC) of the cervix in a uterus didelphys with vaginal septum. The patient was diagnosed with Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) stage IIB because of infiltration to the left parametrium without infiltration to the pelvic wall. The patient was treated with external-beam radiotherapy (EBRT) and brachytherapy (BT), using concomitant chemotherapy with cisplatin.

Photon and electron backscatter dose and energy spectrum analysis around Lipiodol using flattened and unflattened beams.

Purpose: The aim of the current study was to evaluate the backscatter dose and energy spectrum from the Lipiodol with flattening filter (FF) and flattening filter-free (FFF) beams. Moreover, the backscatter range, that was defined as the backscatter distance (BD) are revealed.

Methods: 6 MVX FF and FFF beams were delivered by TrueBeam.

Automatic contrast medium extraction system using electron density data with dual-energy CT.

Objective:: The purpose of the current study is to create a contrast medium extraction method using raw-data-based electron density (rED) and CT number from dual-energy CT (DECT) for automatic delineation of the contrast region.

Methods:: A CT-ED phantom containing tissue-equivalent inserts and an acrylic phantom with an iodinated contrast medium were scanned by DECT. The contrast medium extraction system was created using Python.

Relative biological effectiveness study of Lipiodol based on microdosimetric-kinetic model.

Objectives: We examine the contrast agent Lipiodol effect on the relative biological effectiveness (RBE) values for flattening filter free (FFF) and flattening filter (FF) beams of 6 MV-Xray (6 MVX) and 10 MVX.

Methods: Lipiodol was placed at 5 cm depth in water. According to the microdosimetric kinetic model, the RBE values for killing the human liver hepatocellular cells were calculated from dose and lineal energy (yd(y)) from Monte Carlo simulations.

Interfractional diaphragm changes during breath-holding in stereotactic body radiotherapy for liver cancer.

Aim And Background: IGRT based on bone matching may produce a large target positioning error in terms of the reproducibility of expiration breath-holding on SBRT for liver cancer. We evaluated the intrafractional and interfractional errors using the diaphragm position at the end of expiration by utilising Abches and analysed the factor of the interfractional error.

Materials And Methods: Intrafractional and interfractional errors were measured using a couple of frontal kV images, planning computed tomography (pCT) and daily cone-beam computed tomography (CBCT).

Effect of secondary electron generation on dose enhancement in Lipiodol with and without a flattening filter.

Purpose: Lipiodol, which was used in transcatheter arterial chemoembolization before liver stereotactic body radiation therapy (SBRT), remains in SBRT. Previous we reported the dose enhancement in Lipiodol using 10 MV (10×) FFF beam. In this study, we compared the dose enhancement in Lipiodol and evaluated the probability of electron generation (PEG) for the dose enhancement using flattening filter (FF) and flattening filter free (FFF) beams.

Energy spectrum and dose enhancement due to the depth of the Lipiodol position using flattened and unflattened beams.

Aim: Lipiodol was used for stereotactic body radiotherapy combining trans arterial chemoembolization. Lipiodol used for tumour seeking in trans arterial chemoembolization remains in stereotactic body radiation therapy. In our previous study, we reported the dose enhancement effect in Lipiodol with 10× flattening-filter-free (FFF).

Accuracy of the raw-data-based effective atomic numbers and monochromatic CT numbers for contrast medium with a dual-energy CT technique.

Objective: To evaluate the accuracy of raw-data-based effective atomic number (Z) values and monochromatic CT numbers for contrast material of varying iodine concentrations, obtained using dual-energy CT.

Methods: We used a tissue characterization phantom and varying concentrations of iodinated contrast medium. A comparison between the theoretical values of Z and that provided by the manufacturer was performed.

Marginal prescription equivalent to the isocenter prescription in lung stereotactic body radiotherapy: preliminary study for Japan Clinical Oncology Group trial (JCOG1408).

A new randomized Phase III trial, the Japan Clinical Oncology Group (JCOG) 1408, which compares two dose fractionations (JCOG 0403 and JCOG 0702) for medically inoperable Stage IA NSCLC or small lung lesions clinically diagnosed as primary lung cancer, involves the introduction of a prescribed dose to the D of the planning target volume (PTV) using a superposition/convolution algorithm. Therefore, we must determine the prescribed dose in the D prescribing method to begin JCOG1408. JCOG 0702 uses density correction and the D prescribing method.

Dosimetric impact of Lipiodol in stereotactic body radiation therapy on liver after trans-arterial chemoembolization.

Purpose: Stereotactic body radiation therapy (SBRT) combining trans-arterial chemoembolization (TACE) with Lipiodol is expected to improve local control. This study is aimed to estimate the dose enhancement in Lipiodol's proximity and to evaluate the dose calculation accuracy of the Acuros XB (AXB) algorithm and anisotropic analytical algorithm (AAA) in the Eclipse treatment planning system (TPS) (ver. 11, Varian Medical Systems, Palo Alto, USA), compared with that of the Monte Carlo (MC) calculation (using BEAMnrc/DOSXYZnrc code) for a virtual phantom and a treatment plan for liver SBRT after TACE.

Absorbed dose and image quality of Varian TrueBeam CBCT compared with OBI CBCT.

Purpose: Nowadays, patient positioning and target localization can be verified by using kilovolt cone beam computed tomography (kV-CBCT). There have been various studies on the absorbed doses and image qualities of different kV-CBCT systems. However, the Varian TrueBeam CBCT (TB CBCT) system has not been investigated so far.

Impact of reduction of flux overlap region on kilovoltage cone-beam computed tomography image quality and patients' exposure dose.

Aim: In high-precision radiation therapy, kilovoltage cone-beam computed tomography plays an important role in verifying the position of patient and localization of the target. However, the exposure dose is a problem with kilovoltage cone-beam computed tomography. Flux overlap region increases the patient dose around the center when the scan is performed in a full-scan mode.

Evaluation of beam modeling for small fields using a flattening filter-free beam.

The characteristics of a flattening filter-free (FFF) beam are different from those of a beam with a flattening filter. For small-field dosimetry, the beam data needed by the radiation treatment planning system (RTPS) includes the percent depth dose (PDD), off-center ratio (OCR), and output factor (OPF) for field sizes down to 3 × 3 cm to calculate the beam model. The purpose of this study was to evaluate the accuracy of calculations for the FFF beam by the Eclipse treatment planning system for field sizes smaller than 3 × 3 cm (2 × 2 and 1 × 1 cm).

Availability of applying diaphragm matching with the breath-holding technique in stereotactic body radiation therapy for liver tumors.

Purpose: Image-guided radiotherapy (IGRT) based on bone matching can produce large target-positioning errors because of expiration breath-hold reproducibility during stereotactic body radiation therapy (SBRT) for liver tumors. Therefore, the feasibility of diaphragm-based 3D image matching between planning computed tomography (CT) and pretreatment cone-beam CT was investigated.

Methods: In 59 liver SBRT cases, Lipiodol uptake after transarterial chemoembolization was defined as a tumor marker.

[Availability of using diaphragm matching in stereotactic body radiotherapy (SBRT) at the time in breath-holding SBRT for liver cancer].

Purpose: Liver image guided radiation therapy (IGRT) based on bone matching risks generating serious target positioning errors for reasons of lack of reproducibility of expiration breath hold. We therefore investigated the feasibility of 3D image matching between planning CT images and pretreatment cone-beam computed tomography (CBCT) images based on diaphragm surface matching.

Method: 27 liver stereotactic body radiotherapy (SBRT) cases in whom trancecatheter arterial chemoembolization (TACE) had been performed in advance of radiotherapy were manually image-matched based on contrast, Lipiodol used in the TACE as the marker of the tumor, and the relative coordinates of the isocenter obtained by contrast matching, defined as the reference coordinate.

[Study of setup margins in radiation therapy: how many verification times and patients are required].

Introduction: The purpose of this research is to require suitable numbers of verification times and patients for calculating the setup margin (SM) in radiotherapy.

Methods: 1) This simulation was performed using the standard normal distribution random number. The simulation used the seven levels of verification from 5 to 35 in 5 steps, and 35 patients.

Inverse relationship between serum erythropoietin and blood lead concentrations in Kathmandu tricycle taxi drivers.

Objective: Kathmandu tricycle taxi drivers, whose environmental lead (Pb) exposure is ascribable mainly to vehicular exhaust, were studied to examine a dose-response relationship between blood Pb (Pb-B) and serum erythropoietin (sEPO) concentrations.

Methods: Subjects were 27 drivers and 9 non-drivers. They were non-anemic healthy men with normal renal function.

Study on physical and some serum parameters of inhabitants living in agricultural Terai region, Nepal.

Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltranspeptidase (gamma-GTP), lactate dehydrogenase (LDH), urea nitrogen (BUN), uric acid (UA) and creatinine (CRE) levels were examined in 183 people (98 males and 85 females aged 10 to 68 years) living in Terai region in Nepal. The mean values of serum components examined did not differ by sex in the age group of 10-14 years. The mean values of serum AST, ALT and gamma-GTP levels differed significantly between the sexes (P<0.

Food consumption and serum nutritional status of people living in the Kathmandu valley in Nepal.

Objective: The food consumption and serum nutritional status of people living in the Kathmandu valley, Nepal, were examined to obtain actual data for comparison with our previous findings.

Methods: A dietary survey of 45 males and 60 females was carried out in March 1997 by the 24-hr dietary recall method and nutrient intake was calculated from food tables of India and Japan. Fasting venous blood samples were obtained and serum biochemical parameters were measured using clinical kits.

Food and nutrient intakes among nomads living in three different areas of Inner Mongolia, China.

The subjects, from Mongolian-style gel tribes, aged 6-79 years, living in three different areas of Inner Mongolia, were asked about their daily food consumption in August 2001 using the 24-hr dietary recall method. There were no significant differences in food intakes between males and females of the same age group in the same area, with a few exceptions, although considerable variation was found among individuals and areas for the amount of foods consumed. Some subjects consumed greater amounts of wheat, vegetables, fruits, and vegetable oils, which suggested they had changed their eating patterns.

Reproducibility of organ position using voluntary breath-hold method with spirometer for extracranial stereotactic radiotherapy.

Purpose: To evaluate in healthy volunteers the reproducibility of organ position using a voluntary breath-hold method with a spirometer and the feasibility of this method for extracranial stereotactic radiotherapy in a clinical setting.

Methods And Materials: For this study, 5 healthy volunteers were enrolled. After training sessions, they held their breath at the end-inspiration and the end-expiration phase under spirometer-based monitoring.

Serum nutritional status of tocopherol and retinol normalized to lipids of persons living in the southern rural Terai region in Nepal.

Objective: The present study examined the levels of serum α-Tocopherol (Toc), retinol (Ret), cholesterol (Chol) and triglycerides (TG), and their correlations in the sera of people in Nepal.

Methods: The survey was conducted on the general populace in the agricultural Terai region in southern Nepal. The study population consisted of 93 males and 83 females aged 10-68 years.