Diagnostic Radiology

Introduction
The Division of Diagnostic Radiology is committed to improving health through excellence　in image　oriented patient care and research. Our Division performs more than 61,000 inpatient and outpatient procedures　annually. The division also conducts clinical scientific researches as well as basic scientific ones. And the results　translate directly into better patient care.

Routine Activities　
Our division has four helical CT scanners including two multi-slice CT scanners, two 1.5T MRI systems,two digital subtraction angiographic (DSA) systems, two gamma cameras with the capacity for single photon　emission CT (SPECT), two digital radiographic (DR) systems for fluoroscopy, two mammography and four　computed radiographic (CR) systems. One DSA system is equipped with helical CT, and is also referred to as an　IVR-CT system. Last year, positron emission tomography (PET) scanner and baby cyclotron had been　introduced, and tumor imaging by 18F-FDG (fluorodeoxyglucose) has been started as a part of Advanced　Frontier Medical Care. These all-digital image systems enhance the efficacy of routine examination.　
This division has six consulting radiologists and fourteen technologists. As part of routine work, every　effort is made to produce an integrated report covering all examinations, such as plain radiographic examinations　(chest, abdomen, head, neck, breast, bone and other structures), contrast radiological procedures (digestive,urinary and respiratory tracts), CT, MRI, RI, PET, angiography and interventional radiology (IVR), mainlytransarterial embolization (TAE).
The number of cases examined in 2001 is shown in the table below. We have noted that the main diagnosticmodalities for several cancers have been shifting from plain film to CT and MRI.
Several conferences are routinely held in our division, including teleradiologic, pre- and post-operativeconferences.

Research Activities
Our division has been developing a system of multi-slice helical CT with the support of the national project of Comprehensive 10-year Strategy for Cancer Control and the new 10-year Strategy for Cancer Control.
The prospective study of detecting small tumors in biliary tract and pancreas using multi-slice helical CT is ongoing.
Multi-slice helical CT is also applicable to screening of lung cancers. A feasibility study is now ongoing in cooperation with the thoracic oncology groups at the National Cancer Center Hospital (NCCH) and the Anti-Lung Cancer Association.
Using an exclusive optical fiber line between the Tsukiji and Kashiwa campuses, regular and optional image conferences have been held. By extension of this network, these conferences have been opened to other cancer centers, as well as other national hospitals.
By using the recent advancement of computer graphics, our division has achieved great success in obtaining three-dimensional displays of the internal body, based on imaging data from multi-slice helical CT and MRI. This is useful for planning surgery or radiotherapy, for doctors training, and for patient education.
We put high resolution and high speed body MR imaging to practical use by SENSE (sensitivity enchoding) method. This new technique brought not only shortening of imaging acquisition time but also increase in number of imaging through one breath hold.
High Resolution (the size of 1 pixel is 50I) Fuji Computed Radiography Mammography system (HR FCR-MMG) is being developed. HR FCR-MMG is superior to the usual FCR-MMG (one pixel is 100I) in detecting microcalcifications associated with breast cancer, and provided favorable outcomes in overall detection of breast cancer.
A new computer-aided diagnosis (CAD) system using FCR (Fuji Computed Radiography) mammo-grams was introduced to study computerized detection for breast cancerous mass and minimal lesions of microcalcification. Sensitivity to breast cancerous mass and microcalcification were 83% and 96%, respectively. False-positive rates were 2.1 and 0.5 per image, respectively.
Also another CAD system for lung cancer using multi-slice helical CT images is being developed. These CAD systems promise to have a great influence on cancer diagnosis as well as on patient care in the near future.

New Developments
1. One MRI scanner was renewed as the high power gradient (150 mT/m) machine with SENSE method. It is a new technique for shortening of acquisition time using parallel coils.
2. Positron emission tomography (PET) imaging by 18F-FDG has been started as a part of Advanced Frontier Medical Care.

S. NAWANO

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