[Study of X-ray Beam Quality and Contrast-to-Noise Ratio of Lung Nodules in Chest FPD Radiography: Monte Carlo Simulation Using Chest Model Phantom].

Objectives: Contrast-to-noise ratio (CNR) of four X-ray beams (90 kV with 0.15-mm Cu filter, 90 kV with 0.2-mm Cu filter, 120 kV without filter and 120 kV with 0.

[Optimal Beam Quality in Chest Radiography Using CsI-flat Panel Detector for Detection of Pulmonary Nodules].

Objectives: Optimal beam quality for detection of pulmonary nodules in digital chest radiography using CsI-flat panel detector (FPD) was investigated in consideration of image quality and patient dose.

Methods: The human chest phantom with inserted imitated nodules (diameter: 10 mm, CT value: +30 Hounsfield unit (HU), -375 HU, -620 HU) was used for the measurement of contrast-to-noise ratio (CNR) of imitated nodules by twenty beams arranged by five tube voltages and four filters.

Results: The CNR varies with X-ray tube voltage and added filter.

[Evaluation of 90 kV Beam with 0.15 mm Cu Filter in Chest Radiography Using CsI-flat Panel Detector].

Purpose: To compare the visibility of anatomic structure in chest radiography acquired with different beam quality (120 kV beam and 90 kV beam with 0.15 mmCu) using CsI-flat panel detector.

Method: Pair image obtained by different beam quality of 100 person's chest radiographies which were taken periodical health examination were compared with the visibility of normal structures (pulmonary vessels) and abnormal opacities by two pulmonologists and four radiological technologists.

[Invention of Optical Sight in Mobile Radiography with Anti-scatter Grid].

In radiography with anti-scatter grid, it is important to make sure that the X-ray beam direct exactly perpendicular to the grid plane. However, it is so difficult to ensure in mobile radiography. An optical sight to ensure X-ray alignment in mobile radiography with anti-scatter grid was devised.

[Improvement of the Radiographic Contrast in Off-center Radiography with Focused Grid].

In radiography with focused grid, it is important to agree the X-ray center on the grid center. Actually, radiography is often put the off-center alignment which disagrees the X-ray center to the grid center. This misalignment decreases radiographic contrast because of cutoff the primary X-rays.

[Wrapping of X-ray Cassette by a Plastic Bag in Portable Radiography: For Infection Prevention and Alleviation of Patient's Discomfort].

Portable radiography is available for the patient who is postoperative, severe condition and old. As they have weak immunity, it is important to prevent from hospital infection. Wrapping of 14×14 inch or 14×17 inch X-ray cassette by a plastic (polyethylene) bag a little bit bigger than the cassette was proposed for infection prevention in portable radiography.

[Optimal beam quality for chest digital radiography].

To investigate the optimal beam quality for chest computed radiography (CR), we measured the radiographic contrast and evaluated the image quality of chest CR using various X-ray tube voltages. The contrast between lung and rib or heart increased on CR images obtained by lowering the tube voltage from 140 to 60 kV, but the degree of increase was less. Scattered radiation was reduced on CR images with a lower tube voltage.

[Development of unique supporting pad for performing chest radiography on patients in wheelchairs].

Chest radiography is a widely used X-ray inspection. The numbers of patients who use wheelchairs in everyday life has increased in Japan, and their need for radiography has also increased. A unique supporting pad that enables chest radiography for patients in wheelchairs has been developed.

[Analysis of patient flow by radiology information system].

HIS (hospital information system) and PACS (picture archiving and communication system) have become widely popular in clinical offices, and use of RIS (radiology information system) in the department of radiology has spread, creating networking between HIS, PACS, and diagnostic systems. RIS receives patient data and order data from HIS and sends them to the diagnostic systems. On the other hand, the RIS sends the implementation record and accounting data to HIS.

[Radiation dose to the operator's hands during non-vascular radiology involving surgical technique-comparison between under-table method and over-table method].

In non-vascular interventional radiology (IVR) such as percutaneous transhepatic cholangio-drainage (PTCD) and nerve block, the operator's hands are irradiated in primary x-ray field. In Over-table tube fluoroscopy system, operator's hands inevitably are exposed excessively to intensive primary radiation, whereas in the Under-table tube fluoroscopy system, they are irradiated weakly by attenuated radiation through the patient's body. For this reason, the dose to the operator's hands in Under-table tube fluoroscopy is less than in Over-table tube fluoroscopy.