A Remark on Long Range Effect for a System of Semilinear Wave Equations

In this paper we consider the Cauchy problem for a system of semilinear wave equations whose nonlinearity has long range effect on the solution. Such a result was obtained by Kubo, Kubota, and Sunagawa (Math. Ann. 335 (2006)) under the assumption that the initial data are radially symmetric. The aim of this paper is to remove the radial symmetricity of the initial data for typical cases of the nonlinearities

Gastric Hyperplastic Polyp Associated with Proliferation of Xanthoma Cells Observed by Magnification Narrow-Band Imaging Endoscopy

A case of gastric hyperplastic polyp with proliferation of xanthoma cells is reported. The patient was a 69-year-old man who visited our hospital for further evaluation of gastric polyps. Endoscopic examination of the upper digestive tract revealed multiple hyperplastic polyps in the gastric antrum. There was a pedunculated polyp with whitish yellow granules, 7 mm in diameter, arising from the greater curvature of the antrum. Magnification narrow-band imaging endoscopy (GIF-H260Z, Olympus) revealed long microcapillaries in the polyp but did not reveal disappearance of the mucosal microstructure or irregular branched capillaries. Endoscopic mucosal resection (EMR) was performed. Histological examination of the specimen revealed the lengthened gastric foveolae in the superficial portion and tight sheet of foamy histiocytes in the lamina propria. Diagnosis of gastric hyperplastic polyp with proliferation of xanthoma cells was made. There was no evidence of malignancy. It is necessary to know that a gastric hyperplastic polyp may associate with gastric xanthoma, although such association is very rare

HFIGMI–VMAT for brain metastases

Volumetric-modulated arc therapy (VMAT) can be used to design hypofractionated radiotherapy treatment plans for multiple brain metastases. The purpose of this study was to evaluate treatment outcomes of hypofractionated image-guided multifocal irradiation using VMAT (HFIGMI–VMAT) for brain metastases. From July 2012 to December 2016, 67 consecutive patients with 601 brain metastases were treated with HFIGMI–VMAT at our institution. The prescribed dose was 50 Gy to a 95% volume of the planning target volume in 10 fractions. Fifty-five of the 67 patients had non-small-cell lung cancer, and the remaining 12 had other types of cancer. The median number of brain metastases was five, and the median maximum diameter was 1.2 cm. The median duration of follow-up was 12.0 months (range, 1.9–44.8 months), and the median survival time 18.7 months. Four patients with six lesions had local recurrences. The local control rate in the 64 assessed patients was 98.4% and 95.3% at 6 and 12 months, respectively (three died before assessment). The local control rate for the 572 assessed lesions was 99.8% and 99.3% at 6 and 12 months, respectively. Thirty-nine patients developed distant brain metastases, the distant brain control rate being 59.7% and 40.5% at 6 and 12 months, respectively. Acute toxicities were generally mild (Grade 1–2). Three patients (4.5%) developed radiation necrosis requiring corticosteroid therapy. The HFIGMI–VMAT technique with flat dose delivery was well tolerated and achieved excellent local control. This technique is a promising treatment option for patients with multiple and large brain metastases

Effect of dental metal artifact conversion volume on dose distribution in head‐and‐neck volumetric‐modulated arc therapy

Purpose: During treatment planning for head‐and‐neck volumetric‐modulated arc therapy (VMAT), manual contouring of the metal artifact area of artificial teeth is done, and the area is replaced with water computed tomography (CT) values for dose calculation. This contouring of the metal artifact areas, which is performed manually, is subject to human variability. The purpose of this study is to evaluate and analyze the effect of inter‐observer variation on dose distribution. Methods: The subjects were 25 cases of cancer of the oropharynx for which VMAT was performed. Six radiation oncologists (ROs) performed metal artifact contouring for all of the cases. Gross tumor volume, clinical target volume, planning target volume (PTV), and oral cavity were evaluated. The contouring of the six ROs was divided into two groups, small and large groups. A reference RO was determined for each group and the dose distribution was compared with those of the other radiation oncologists by gamma analysis (GA). As an additional experiment, we changed the contouring of each dental metal artifact area, creating enlarged contours (L), reduced contours (S), and undrawn contours (N) based on the contouring by the six ROs and compared these structure sets. Results: The evaluation of inter‐observer variation showed no significant difference between the large and small groups, and the GA pass rate was 100%. Similar results were obtained comparing structure sets L and S, but in the comparison of structure sets L and N, there were cases with pass rates below 70%. Conclusions: The results show that the artificial variability of manual artificial tooth metal artifact contouring has little effect on the dose distribution of VMAT. However, it should be noted that the dose distribution may change depending on the contouring method in cases where the overlap between PTV and metal artifact areas is large

Changes of tumor and normal structures of the neck during radiation therapy for head and neck cancer requires adaptive strategy

The treatment period over which radiation therapy is administered extends over several weeks. Since tumor shrinkage in response to radiation therapy and weight loss due to radiation-induced mucositis may impact on the dose distribution in both target and organ at risk in patients with head and neck cancer, the anatomical changes of tumor and neck volumes during this period should be taken into consideration. We investigated the anatomical changes that occurred in the target and normal structure of the neck during radiation therapy for pharyngeal cancer, and evaluated the necessity of an adaptive strategy. Ten patients with pharyngeal cancer who underwent radical chemoradiation therapy using 3-dimensional conformal radiation therapy RT (66-70 Gy in 33-35 fractions) between April 2009 and September 2010 were enrolled in the study. Patients underwent CT scans every week during their course of treatment. We analyzed the CT data in the radiation treatment planning system and measured changes of tumor, organ at risk, and neck volume. Gross tumor volume (GTV) was rapidly reduced by 28% of the original volume on average in the first 3 weeks. The right and left submandibular glands volume decreased to 70% and 63% of their initial volumes on average, respectively. The volume of the neck in the radiation fields decreased to 89% of its initial volume on average by the sixth week mainly caused by body weight loss due to acute radiation morbidity. Considerable anatomical change in the radiation filed that will affect dose distribution of the target and organ at risk was observed during radiation therapy for head and neck cancer

Differences between professionals in treatment planning for patients with stage III lung cancer using treatment-planning QA software

Background: The quality of treatment planning for stage III non-small cell lung cancer varies within and between facilities due to the different professions involved in planning. Dose estimation parameters were calculated using a feasibility dose-volume histogram (FDVH) implemented in the treatment planning quality assurance software PlanIQ. This study aimed to evaluate differences in treatment planning between occupations using manual FDVH-referenced treatment planning to identify their characteristics. Materials and methods: The study included ten patients with stage III non-small cell lung cancer, and volumetric-modulated arc therapy was used as the treatment planning technique. Fifteen planners, comprising five radiation oncologists, five medical physicists, and five radiological technologists, developed treatment strategies after referring to the FDVH. Results: Medical physicists had a higher mean dose at D98% of the planning target volume (PTV) and a lower mean dose at D2% of the PTV than those in other occupations. Medical physicists had the lowest irradiation lung volumes (V5 Gy and V13 Gy) compared to other professions, and radiation oncologists had the lowest V20 Gy and mean lung dose. Radiological technologists had the highest irradiation volumes for dose constraints at all indexes on the normal lung volume. Conclusions: The quality of the treatment plans developed in this study differed between occupations due to their background expertise, even when an FDVH was used as a reference. Therefore, discussing and sharing knowledge and treatment planning techniques among professionals is essential to determine the optimal treatment plan for each facility and patient

Jejunal small ectopic pancreas developing into jejunojejunal intussusception: A rare cause of ileus

Intussusception is rare in adults. We describe a 62-year-old man with jejunal ectopic pancreas that led to jejunojejunal intussusception and ileus. The patient was admitted to our hospital because of intermittent abdominal pain. Plain abdominal radiography showed some intestinal gas and fluid levels. Abdominal CT scan demonstrated a target sign suggesting bowel intussusception. Jejunography using a naso-jejunal tube showed an oval-shaped mass about 15 mm in diameter with a smooth surface in the jejunum, which suggested a submucosal tumor (SMT), and edematous mucosa around the mass. Partial jejunal resection was carried out and the resected oval-shaped tumor, 14 mm × 11 mm in size, was found to be covered with normal jejunal mucosa. The tumor was histologically diagnosed as type III ectopic pancreas according to the classification proposed by Heinrich. Abdominal pain resolved postoperatively. This case reminds us that jejunal ectopic pancreas should be included in the differential diagnosis of intussusception caused by an SMT in the intestine

Pedunculated Brunner’s gland hamartoma of the duodenum causing upper gastrointestinal hemorrhage

A case of pedunculated Brunner’s gland hamartoma (BGH) of the duodenum causing upper gastrointestinal (GI) hemorrhage is reported. The patient was a 47-year-old man who visited our hospital for further evaluation of tarry stools and shortness of breath. Endoscopic examination of the upper digestive tract revealed a large peduncular polyp with bleeding, about 30 mm in diameter, arising from the wall of the second portion of the duodenum. GI bleeding occurred from the base of the stalk of the polyp. Endoscopic polypectomy was performed. Histological examination of the specimen revealed that the main body of the polyp contained several lobules of mature Brunner’s gland with areas of cystic dilatation. The surface epithelium consisted of normal duodenal mucosa with areas of focal ulceration. This polyp was diagnosed as a BGH. The symptom of tarry stools resolved after endoscopic resection. Our case shows that treatment is necessary for duodenal BGH if GI bleeding occurs

A Boy Safely Treated with Tyrosine Kinase Inhibitors for Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia with Osteolysis

A three-year-old boy with Philadelphia chromosome-positive B-cell precursor acute lymphoblastic leukemia (Ph+ALL) presented with an osteolytic lesion in his right upper arm. Tyrosine kinase inhibitors (TKIs) such as imatinib and dasatinib are an essential component throughout the course of treatment for Ph+ALL. However, TKIs are reported to affect the bone metabolism. In the treatment course of the current patient, the osteolytic lesion quickly improved despite the continuous use of TKIs, even during the concomitant use of corticosteroids. This suggests that TKIs can be safely given with concomitant corticosteroids to children with Ph+ALL, even when osteolytic lesions are present