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We performed phase III clinical study of AMI-25 (Superparamagnetic iron oxide) for hepatic tumors in 163 cases at the 17 institutions in Japan. In overall evaluation, 141/159 cases (88.7%) were evaluated "useful" or "very useful" for clinical usefulness. For efficacy including the signal to noise ratio (S/N) of liver and the tumor-liver contrast to noise ratio (C/N), 89.6% of hepatocellular carcinomas and 95.0% of metastatic liver cancers were evaluated "effective" or "very effective", respectively. The mild adverse reactions were shown in 10 cases (6.1%), but they disappeared within 25 minutes. The serum iron and ferritin increased and the unsaturated iron binding capacity (UIBC) decreased, but they were showing a tendency to go back to their normal ranges. The AMI-25 (10 mumoles Fe/kg) was proved to be useful and safe contrast agent for the liver tumors in MRI.

The potential usefulness of in vivo 19F NMR spectroscopy for the monitoring of flomoxef sodium (FMOX) kinetics was evaluated. In the experimental study using phantom the minimum concentration of FMOX of which signals could be monitored with 19F NMR spectroscopy was 16 micrograms/ml. In patients with intravenous bolus injection and drip infusion of FMOX (2 g/100 ml), signals from normal heart, liver, and kidney were clearly monitored with 19F NMR spectroscopy. In normal lung any signal was not detected, but in a lung with a cancer associated massive atelectasis the monitoring of signals was possible with 19F NMR spectroscopy in both intravenous and intraarterial injections. Monitoring of FMOX kinetics with in vivo 19F NMR spectroscopy will be useful in clinical applications.

The biological effects of a static gradient magnetic field and its combined effects with ionizing radiation on FM3A cultured cells were investigated. The magnetic strength of the center of the field was 5.8 x 10(-2) T esla, the mean gradient of the magnetic filed was 0.6 T esla/m. The magnetic field influenced cell cycle. The relative amount of cultured cells in G1 phase decreased for eight hours after exposure. The growth rate of the cells was slowed by about 5%. Following exposure to the magnetic field, the survival rate of cells decreased to about 20% less than that of the non-exposed control. The combined effect of 60Co irradiation with exposure to the magnetic field showed a greater effect than a simple additive one. The combined effect was influenced by the interval between 60Co irradiation and exposure to the magnetic field. The biological effects of the magnetic field may be related to age-dependent cellular damage in the cell cycle, blockage of cell progression in the cell cycle, and increased repair from radiation damage.

Transcatheter arterial embolization using a coaxial microcatheter and micro-coil was performed in eight patients with vascular lesions; one each with aneurysm of the basilar artery, cerebellar artery, and pancreatic artery, pseudoaneurysm of the common hepatic artery, gastroduodenal artery, and gluteal artery, carotid-cavernous fistula, and thoracic paraspinal arteriovenous malformation. Complete occlusion was achieved in five patients with aneurysm and pseudoaneurysm by occluding the aneurysmal cavity and/or the orifice. A patient with recurrent carotid-cavernous fistula was also completely embolized. A case of basilar artery aneurysm resulted in partial occlusion because the posterior cerebral artery originated from the aneurysm. The unsatisfactory result in a case of paraspinal AVM was due to its wide extension with multiple feeding arteries. No apparent complication was seen. In conclusion, super-selective arterial embolization therapy with coaxial microcatheter and micro-coils was found to be a useful method for vascular lesions that would have been technically difficult to embolize with the standard catheter and coils.

Skin doses of 100 patients who were treated with high energy ionizing irradiation during conventional irradiation therapy were measured by thermoluminescence dosimeter (TLD). In 87 of the 100 patients, acute hyperemic change of the skin (erythema) of the irradiated region was observed. In the other 13 patients, alopecia of the scalp was observed. The following conclusions were reached. 1) The time-dose relationship was linear when erythema tolerance was used as an index, but not when alopecia was used. 2) The tolerance dose for erythema was lower than previously reported. The slope of the isoeffect curve on the log-log plot of total absorbed skin dose against total number of days after the first irradiation was 0.68 when erythema was used as an index. This number is larger than previously reported results. We considered that erythema is significantly influenced by fraction size and that hyperfractionation is a promising method of irradiation, especially in Japan. 3) Combined use of chemotherapeutic agents, such as 5-Fu, accelerated erythema. The slope of combined treatment was 0.86. Observing acute hyperemic change of skin is considered to be a useful method of investigating the combined effects of chemotherapeutic agents on irradiation.

Mechanical arc scanning is widely used for breast sonography in Japan. The authors have used three different kinds of devices over the past seven years. The diagnostic accuracy was compared among three groups of patients with pathologically confirmed breast masses. In group A, 309 cases (77 carcinomas) were evaluated with a 10 MHz contact compound scanner, and the sensitivity, specificity and accuracy rates were 77.9%, 97.8% and 92.9%, respectively. In group B, 306 cases (56 carcinomas) were evaluated with a 5 or 7.5 MHz mechanical arc scanner, and the sensitivity, specificity and accuracy rates were 89.3%, 84.8% and 85.6%, respectively. In group C, 296 cases (71 carcinomas) were evaluated with a 7.5 MHz real time scanner, and the sensitivity, specificity and accuracy rates were 95.8%, 92.4% and 93.2%, respectively. In cases with T1 breast cancer, the methods had sensitivities of 60.0%, 85.7% and 94.5%, respectively. The sensitivity of the real-time scanner was not significantly different from that of the mechanical arc scanner. In conclusion, the hand-held real-time scanner with high-frequency transducer is a simple, useful device with high diagnostic accuracy for breast examination and can be used as a substitute for the mechanical arc scanner.

A new method is proposed for external stereotactic and three-dimensional irradiation for a small target in the skull. In this method, we use a special long tube collimator, helmet-type shell (guiding rods are attached to the shell using the CT-stereotactic apparatus) and 10 MV linear accelerator. The patient's head is fixed conservatively by the helmet-type shell. In the phantom experiment, the 90% isodose area was 10 mm in diameter, and the error between the geometrical center of the target and the irradiated center was 2 mm.

We have designed and developed a new database system to facilitate automatic feedback of the content of radiology reports to radiologists. The prototype of this database system has been implemented in the RGSS-IDJ, a developmental computer system that applies artificial intelligence methods to a reporting system. This prototype system was constructed to test the feasibility of overcoming the limitations of conventional database systems. The new database system is based on our semantic model for radiology reports and is able to treat data with unnormalized relations. Operations specific to our database system include the ability to acquire information about a set of reports that contains any semantic expression included in the lexicon and the ability to obtain the expressions that belong to a set of several semantic expressions in the reports. Thus, our new database system will offer a more powerful tool for analyzing the content of reports than conventional database systems.

Transcatheter arterial embolization therapy was performed in fifteen patients with hypervascular metastatic bone and soft-tissue tumors (7 from renal carcinoma, 5 from hepatocellular carcinoma, and one each from breast, thyroid, and cholangiocarcinoma). Sites of metastasis were spine (7), pelvis (5), skull (2), paraspine (2), chest wall (1), and thigh (1). Five patients had not responded to previous radiation therapy and hyperthermia. Embolization of feeding arteries was performed superselectively with long tapered catheters or coaxial microcatheters. Emulsion of Lipiodol and anticancer agent, polyvinyl alcohol sponge, gelatin sponge, and microcoils were used as embolic materials in various combinations. Relief of pain was experienced in 14 of 15 patients. Two patients were operated following embolization with minimal blood loss. Change in tumor size was evaluated by CT or MRI in ten patients. Reduction of tumor size were more than 50% in five patients, from 25% to 50% in two, and no change in three patients. Especially, patients embolized with microcatheter and microcoils showed excellent long-term results. No serious complications were seen. In conclusion, superselective arterial embolization therapy with coaxial microcatheter and microcoils was proved to be an useful treatment for hypervascular metastatic bone and soft-tissue tumors.

In this paper we attempted MR visualization of the vestibular aqueduct (VA) with a surface coil. Sagittal plane was most preferable from the result of preliminary study using a dry temporal bone. In all of ten normal volunteers, VAs were visualized well. In none of them, proton-density weighted spin-echo (SE) images were inferior to both T1- and T2-weighted SE image. In four of eight patients with Menière's disease, VAs were not visualized due to obstruction of VA, although in all of ten non-Menière's patients with hearing loss or vertigo, VAs were well visualized. Although further investigation is needed, MR imaging of VA including both its content and surrounding bony structure would give important information to manage the patients with either Menière's disease or other disorders of internal ears.

Short-term treatment (3 minutes) with low intensity (1.8 w/cm2) ultrasound was applied to human tumors in combined treatment with ionizing radiation. Tumor regression was observed with the dose below TDF (time dose fractionation) 40, and 50% reduction in tumor masses was observed at doses with TDF 45 to 62, and the mean dose was TDF 52. Complete remission of tumor masses was recognized with doses of TDF 62 to 113 in 9 of 10 treated lesions. Five cases, with multiple lesions, were treated with controlled ionizing radiation without ultrasound. Fifty percent reduction in tumor masses was observed with doses of TDF 74 to 113, and the mean dose was TDF 86. Complete remission of tumor mass was not observed. Radioenhancement ratio by ultrasound was 1.6 for 50% tumor reduction. Skin temperature was elevated to about 3 degrees C as measured by thermography, but intradermal temperature was not apparently elevated. Ultrasound potentiates the effects of localized radiotherapy not due to hyperthermia but to the other factors.

We developed a new laser beam generator system which can deliver laser beam to multiple terminals in distant clinical therapy rooms. The system possesses the distribution equipment by which Nd-YAG laser power is distributed to 8 output terminals under the computer control. Distributed laser beam is delivered to each distant terminal with clinical informations through the optical fiber. In the fundamental studies, possibility of distant transportation of laser beam (30 m) only with 10% loss of energy and without dangerous heating at the connection parts was shown. There seems to be no disadvantage associated with distribution laser beam. In the clinical study, the system was applied to five patients with the symptoms including hemosputum, esophageal stenosis, hemorrhage, lip ulcer and pain. Clinical usefulness of the system was proved. The advantages of the system are as follows: 1. Benefit of cost reduction due to multiple use of single laser source. 2. No necessity of transport of the equipment. 3. No requirement of a wide space to install the equipment in the distant room. 4. Efficient management and maintenance of the system by centralization. Further improvements, e.g., simultaneous use at multiple terminals and elongation of transportation up to 340 m, make the system more useful for clinical application.

Retrograde transurethral balloon dilatation of urethral stenosis was performed in five patients: four patients with benign prostatic hypertrophy and one with urethral stricture following open prostatectomy. Significant resolution of symptoms of dysuria was seen in four patients throughout the follow-up period of 12 to 18 months. A balloon diameter of 25 mm was considered to be necessary for prostatic hypertrophy. The unsatisfactory result in one patient with prostatic hypertrophy was believed to be caused by incomplete dilation due to a small balloon diameter. Mild transient hematuria was seen in all cases. Only one patient with postoperative urethral stricture complained of pain during balloon inflation, while other patients with prostatic hypertrophy did not complain of any apparent pain. We conclude that this technique is a safe and effective method of treatment for prostatic hypertrophy and other urethral strictures.

RGSS-IDJ is developed as the Japanese version of Report Generation Support System for Imaging Diagnosis (RGSS-ID), which is a developmental computer system that applies artificial intelligence (AI) methods to a reporting system. Now RGSS-IDJ supports the report generation of cranial computed tomography. A representation scheme called Generalized Finding Representation (GFR) is proposed, to bridge the gap between natural language expressions in the radiographic report and AI methods. GRF for RGSS-IDJ is the same as for RGSS-ID. The basic style for entering the findings on the radiograph is the dialogue system with the routine of query and answering it by selecting items with a mouse. This system encodes the input findings into the network expressions, which are represented as the list form in the LISP computer language. And, it reserves them into the knowledge data base. The content of the report will be able to be utilized for various analyses within AI paradigm. The final radiographic report is made in the natural Japanese language.

X-ray sheet film images of the test chart, the vascular phantom and angiography were digitized at sampling pitch of 0.2 mm and 0.15 mm using film digitizer TFR-01 (Toshiba) and transferred to a device for image storage and display system with 1635-line display monitor (TDF-500AS, Toshiba). Comparison of image qualities between film- and CRT-images was performed in fundamental and clinical studies. Resolution of the test chart image of conventional radiography was worse on CRT than on the original film, although it was improved when film image was digitized at resolution of 0.15 mm/pixel in comparison with that at resolution of 0.2 mm/pixel. Moiré stripes which occurred due to interference were found on CRT images taken using a grid technique. On CRT images of X-ray sheet film using direct magnification technique moiré stripes were not produced because of non grid technique, and the resolution approached that of the original film. In the study using vascular phantom, the optimal image on CRT could be obtained by various image processing procedures, and image quality on CRT with resolution of 0.15 mm approached that of original film. In case of direct magnification CRT images were superior to film images. Subtraction image of the vascular phantom at resolution of 0.2 mm/pixel was obtained on CRT and compared with film subtraction image. On conventional subtraction CRT image moiré stripes impaired the image quality in comparison with the film subtraction. However, magnification subtraction image of the vascular phantom on CRT was superior to the film subtraction. The results obtained in the test chart studies and phantom studies were also confirmed in clinical studies using various kind of angiograms. In addition, ROC study using clinical angiograms showed no significant statistical differences between the original film and CRT image even with 0.2 mm matrix size. Angiographic image on CRT at resolution of 0.15 mm/pixel or less is available for clinical use in place of conventional film image.