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At the National Institutes for Quantum Science and Technology (QST), a multi-ion therapy using helium, carbon, oxygen, and neon ions has been studied for charged particle therapy with more optimal biological effects. To make multi-ion therapy clinically feasible, a new treatment system was developed to realize the changes of the ion species in each irradiation using the Heavy Ion Medial Accelerator in Chiba (HIMAC). Since radiation therapy is safety-critical, it is necessary to construct a safety system that includes multiple safety barriers in the new treatment system for multi-ion therapy and to perform a safety analysis for the prevention of serious accidents. In this study, we conducted a safety analysis using event tree analysis (ETA) for newly introduced processes in the treatment planning, accelerator, and irradiation system of the multi-ion therapy. ETA is an optimal method to verify multiple safety barriers that are essential for medical safety and to shorten the time for safety analysis by focusing only on the new processes. Through ETA, we clarified the types of malfunctions and human errors that may lead to serious accidents in the new system for multi-ion therapy, and verified whether safety barriers such as interlock systems and human check procedures are sufficient to prevent such malfunctions and human errors. As a result, 6 initial events which may lead to serious accidents were listed in the treatment planning process, 16 initial events were listed in the accelerator system, and 13 initial events were listed in the irradiation system. Among these 35 initial events, 5 cautionary initial events were identified that could lead to serious final events and they had a probability of occurrence higher than 10 -4 . Meanwhile, the others were all initial events that do not lead to serious accidents, or the initial events that can lead to serious accidents but were considered to have sufficient safety barriers. The safety analysis using ETA successfully identified the system malfunctions and the human errors that can lead to serious accidents, and the multiple safety barriers against them were systematically analyzed. It became clear that the multiple safety barriers were not sufficient for some initial events. We plan to improve the safety barriers for the five cautionary initial events before the start of the clinical trial. Based on these findings, we achieved our objective to conduct a safety analysis for a new treatment system for multi-ion therapy. The safety analysis procedure using ETA proposed by this study will be effective when new systems for radiotherapy are established at QST and other facilities in the future as well.

Aromatic sulfonamides exist in a synclinal conformation with the twisted structure arising from rotation around the S-N bond in both the solid state and in solution. Simple bidentate ligands containing the sulfonamide moiety can be extended to form elongated ligands, and optically active components can be added to form a versatile building block for the construction of coordination polymers with many structures. Mixing the simple ligands 1 and 2 and the elongated ligands 3 and 4 with different Ag(I) salts yielded the corresponding complexes [Ag(1)OTf]n (1a), [Ag(2)]n•nOTf(2a), [Ag(3)OTf]n (3a), [Ag(3)]n•nBF₄ (3b), [Ag(4)CH₃CN]n•nBF₄•nCHCl₃ (4b), and [Ag(4)]n•nSbF₆•nCH₄O (4c). Straight chains and racemic helical polymers were observed in the crystal structure of complexes 1a and 2a, respectively. In the crystal structures of complexes 3a and 4b, infinite 1D straight chains containing a T-shaped coordination geometry about the Ag(I) centers were formed by the reaction of ligands 3 or 4 with Ag(I) salts in CH₃CN/CHCl₃. A continuous 1D coordination polymer containing a racemic mixture of left- and right-handed helices formed in the crystal structure of complex 3b. Furthermore, a layered coordination polymer consisting of a racemic mixture of left- and right-handed polymers was observed from the crystal structure of complex 4c. The construction of optically pure left- or right-handed 1D helical polymers via the introduction of chiral functional groups on the nitrogen atom of the sulfonamide ligand is currently under investigation in our laboratory.

Foreign-body aspiration (FBA) obstructing the airways may lead to choking and cardiopulmonary arrest without immediate emergency care. We retrospectively reviewed medical records of 17 otorhinolaryngology subjects-8 men and 9 women aged 0 to 84 years-88% of whom were < 3 years old, requiring tracheobronchial FBA between January 1995 and October 2006 and of 62 emergency subjects-43 men and 19 women aged 0 to 91 years--10% of whom were < 3 yeares old 68% of whom > or = 50 years old, admitted between January 2000 and October 2006. Emergency Department personnel saw a mean of 8.9 patients per year versus the mean of 1.4 patients per year seen by Otorhinolaryngology Department personnel. Foreign bodies extracted most frequently from the 17 otorhinolaryngology patients were 9 seen for peanut injestion followed by 1 each seen for bean, screw, and false teeth injestion among other objects. Sixteen of the 17 were discharged without complications. Foreign bodies extracted from the 62 emergency patients most frequently involved food, especially rice cakes. Over half seen had already gone into cardiopulmonary arrest upon arrival and required cardiopulmonary resuscitation. Of the 62, 32 patients died, 13 were sent to another hospital after in-patient care, 9 were sent home without admission, and 7 were discharged without complications.

In order to evaluate the safety and pharmacokinetics of gadolinium contrast agents in patients with hemodialysis, in vitro and clinical studies were performed. Gd-DTPA and Gd-HP-DO3A solutions were dialysed by standard methods. One classic type (cellulose acetate) and two high-performance types (PMMA and polyacrylonitrile) were used. Eleven dialysis patients underwent normal dose contrast MRI followed by usual dose hemodialysis (HD). PMMA dialysis membranes were used for 8 patients and cellulose acetate membranes for 3 patients. Serum levels of gadolinium, BUN and creatinine were analyzed before and after the 1st HD and after the 2nd, 3rd and 4th HD. Side effects and edema were carefully observed. In vitro studies showed that 11.1 hours of dialysis would be necessary to remove 97% of the injected dose of contrast agent by using a first-order kinetic model of dialysis time. When dialysis membranes and contrast agents were compared, statistically significant differences were noted between dialysis membranes and all contrast agents. In the clinical study, 79.1% of the contrast agent was dialyzed after the 1st dialysis and 99.6% after the 4th dialysis. These results showed that all contrast agents and both dialysis membranes were suitable. Neither changes in laboratory parameters nor side effects were observed. The present study suggests, consequently, there are no contraindications when using the ordinary dose of contrast agent even in patients with dialysis.

We report our experience with the use of three saphenous vein grafts for treating advanced occlusive cerebrovascular disease in the anterior cerebral artery (ACA) in two patients. Superficial temporal artery (STA)-ACA anastomosis with interposed vein graft is thought to be indicated for patients who have STA of insufficient length to anastomose to the ACA. Vein graft has already been demonstrated to be applicable in extracranial-intracranial artery bypass, as well as in aorto-coronary bypass. Two factors considered to be essential for successful revascularization are technical proficiency, including protection from drying, smooth approximation of vessels, and proper orientation of the graft, and the relative size of donor and recipient vessels. Because the vein graft must be anastomosed with the proximal ACA to reduce the size discrepancy between vessels, prolonged interruption of circulation during suturing is inevitable. Our operative results suggest that anastomosis to a superficial branch of the ACA just distal to the interhemispheric fissure seems to be preferable to anastomosis using vein graft, and we recommend the option of vein graft only when the STA cannot be used.

Malignant fibrous histiocytoma (MFH) has been rarely reported as a primary tumor of the heart. We present a case of a primary intracardiac MFH and review the 28 previous reports of this rare cardiac tumor. A 48-year-old woman underwent an operation for congestive heart failure (CHF) due to a left atrial tumor. A large multinodular tumor attached to the posterior wall of the left atrium and extended into the mitral annulus and the posterior leaflet of the mitral valve. The tumor was resected incompletely and mitral valve replacement was performed. Pathological diagnosis was MFH. The patient did well in the postoperative period, but she again presented with symptoms of CHF four months later. Chest CT and two-dimensional echocardiogram demonstrated a recurrent tumor of the left atrium. Since the tumor grew rapidly despite chemotherapy, a reoperation was performed to remove it. Nevertheless, as the tumor was found to have extended into the pericardial cavity and posterior mediastinum, only partial resection was possible. After a protracted operation, the heart failed to sustain the circulation and the patient died. The prognosis of intracardiac MFH was poor in spite of surgery, radiation and/or chemotherapy. However, repeated surgical treatments can relieve symptoms of CHF and may prolong the life of patients.