Evaluation of calibration factor of OSLD toward eye lens exposure dose measurement of medical staff during IVR

The eye lens is a sensitive organ of which an x‐ray exposure dose should be managed during interventional radiology (IVR). In the actual situations, the eye lens is exposed to scattered x‐rays; they have different from the standard x‐ray energies which are used for general dose calibration of the dosimeter. To perform precise dose measurement, the energy dependence of the dosimeter should be properly accounted for when calibrating the dosimeter. The vendor supplies a calibration factor using 80‐kV diagnostic x‐rays under a free‐air condition. However, whether it is possible to use this calibration factor to evaluate the air kerma during the evaluation of the eye lens dose is unclear. In this paper, we aim to precisely determine calibration factors, and also examine the possible application of using a vendor‐supplied calibration factor. First, the x‐ray spectrum at the eye lens position during fluoroscopy was measured with a CdTe x‐ray spectrometer. We mimicked transfemoral cardiac catheterization using a human‐type phantom. Second, we evaluated the doses and calibration factors at three dosimetric points: front and back of protective goggles, and the front of the head (eye lens position). We used the measured x‐ray spectrum to determine the incident photon distribution in the eye lens regions, and x‐ray spectra corresponding to the dosimetric points around the eye lens were estimated using Monte Carlo simulation. Although the calibration factors varied with dosimetric positions, we found that the factors obtained were similar to the vendor‐supplied calibration factor. Furthermore, based on the experiment, we propose a practical way to calibrate an OSL dosimeter in an actual clinical situation. A person evaluating doses can use a vendor‐supplied calibration factor without any corrections for energy dependences, only when they add a systematic uncertainty of 5%. This evidence will strongly support actual exposure dose measurement during a clinical study

Ancient Cytokine Interleukin 15-Like (IL-15L) Induces a Type 2 Immune Response

Acknowledgments We thank Mrs. Susann Schares and Katrin Giesow for excellent technical assistance and Dr. Gunther Keil for his valuable advice regarding expression of recombinant proteins in insect cells. We also thank Prof. Oriol Sunyer from the University of Pennsylvania, USA, for providing us mAbs against rainbow trout CD4. A large part of this manuscript has been released as a pre-print (116). Funding TY and UF were supported by the EU FP7 Grant 311993 (TARGETFISH) and the German Research Council Grant No. FI 604/7-1. JD was supported by the Ministry of Education, Culture, Sports, Science and Technology, Japan, Grants-in-Aid for Scientific Research No. 25450319. TW received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland), that was funded by the Scottish Funding Council (grant reference HR09011). EW was supported by the Ministry of Science and Technology of Thailand and Mahasarakham University.Peer reviewedPublisher PD

Estimation of identification limit for a small-type OSL dosimeter on the medical images by measurement of X-ray spectra

Our aim in this study is to derive an identification limit on a dosimeter for not disturbing a medical image when patients wear a small-type optically stimulated luminescence (OSL) dosimeter on their bodies during X-ray diagnostic imaging. For evaluation of the detection limit based on an analysis of X-ray spectra, we propose a new quantitative identification method. We performed experiments for which we used diagnostic X-ray equipment, a soft-tissue-equivalent phantom (1–20 cm), and a CdTe X-ray spectrometer assuming one pixel of the X-ray imaging detector. Then, with the following two experimental settings, corresponding X-ray spectra were measured with 40–120 kVp and 0.5–1000 mAs at a source-to-detector distance of 100 cm: (1) X-rays penetrating a soft-tissue-equivalent phantom with the OSL dosimeter attached directly on the phantom, and (2) X-rays penetrating only the soft-tissue-equivalent phantom. Next, the energy fluence and errors in the fluence were calculated from the spectra. When the energy fluence with errors concerning these two experimental conditions was estimated to be indistinctive, we defined the condition as the OSL dosimeter not being identified on the X-ray image. Based on our analysis, we determined the identification limit of the dosimeter. We then compared our results with those for the general irradiation conditions used in clinics. We found that the OSL dosimeter could not be identified under the irradiation conditions of abdominal and chest radiography, namely, one can apply the OSL dosimeter to measurement of the exposure dose in the irradiation field of X-rays without disturbing medical images

Entrance surface dose measurements using a small OSL dosimeter with a computed tomography scanner having 320 rows of detectors

Entrance surface dose (ESD) measurements are important in X-ray computed tomography (CT) for examination, but in clinical settings it is difficult to measure ESDs because of a lack of suitable dosimeters. We focus on the capability of a small optically stimulated luminescence (OSL) dosimeter. The aim of this study is to propose a practical method for using an OSL dosimeter to measure the ESD when performing a CT examination. The small OSL dosimeter has an outer width of 10 mm; it is assumed that a partial dose may be measured because the slice thickness and helical pitch can be set to various values. To verify our method, we used a CT scanner having 320 rows of detectors and checked the consistencies of the ESDs measured using OSL dosimeters by comparing them with those measured using Gafchromic™ films. The films were calibrated using an ionization chamber on the basis of half-value layer estimation. On the other hand, the OSL dosimeter was appropriately calibrated using a practical calibration curve previously proposed by our group. The ESDs measured using the OSL dosimeters were in good agreement with the reference ESDs from the Gafchromic™ films. Using these data, we also estimated the uncertainty of ESDs measured with small OSL dosimeters. We concluded that a small OSL dosimeter can be considered suitable for measuring the ESD with an uncertainty of 30 % during CT examinations in which pitch factors below 1.000 are applied

A Cystic Lymphangioma of the Colon Seen in a Patient with Early Gastric Cancer

Lymphangiomas are very rare benign neoplasms of the gastrointestinal tract. A case of cystic lymphangioma in the hepatic flexure of the colon seen in patient with early gastric cancer is reported and the literature is reviewed

Lymphangioma of the Small Intestine : A Case Report

Lymphangiomas of the small intestine are rare tumors arising from masses of dilated lymphatic vessels in the submucosa. There are 11 cases of lymphangioma of the small intestine in the Japanese literature. We report a case of lymphangioma of the jejunum seen in a 76-year-old female and discuss with clinical feature