BACKGROUNDIn head and neck neoplasm survivors treated with brain irradiation, metabolic alterations would occur in the radiation-induced injury area. The mechanism of these metabolic alterations has not been fully understood, while the alternations could be sensitively detected by proton (1H) nuclear magnetic resonance spectroscopy (MRS). In this study, we investigated the metabolic characteristics of radiation-induced brain injury through a long-term follow-up after radiation treatment using MRS in vivo.

METHODSA total of 12 adult Sprague-Dawley rats received a single dose of 30 Gy radiation treatment to semi-brain (field size: 1.0 cm × 2.0 cm; anterior limit: binocular posterior inner canthus connection; posterior limit: external acoustic meatus connection; internal limit: sagittal suture). Conventional magnetic resonance imaging and single-voxel 1H-MRS were performed at different time points (in month 0 before irradiation as well as in the 1st, 3rd, 5th, 7th, and 9th months after irradiation) to investigate the alternations in irradiation field. N-acetylaspartate/choline (NAA/Cho), NAA/creatinine (Cr), and Cho/Cr ratios were measured in the bilateral hippocampus and quantitatively analyzed with a repeated-measures mixed-effects model and multiple comparison test.

RESULTSSignificant changes in the ratios of NAA/Cho (F = 57.37, P_{g < 0.001), NAA/Cr (F = 54.49, Pg < 0.001), and Cho/Cr (F = 9.78, Pg = 0.005) between the hippocampus region of the irradiated semi-brain and the contralateral semi-brain were observed. There were significant differences in NAA/Cho (F = 9.17, Pt < 0.001) and NAA/Cr (F = 13.04, Pt < 0.001) ratios over time. The tendency of NAA/Cr to change with time showed no significant difference between the irradiated and contralateral sides. Nevertheless, there were significant differences in the Cho/Cr ratio between these two sides.}

CONCLUSIONSMRS can sensitively detect metabolic alternations. Significant changes of metabolites ratio in the first few months after radiation treatment reflect the metabolic disturbance in the acute and early-delayed stages of radiation-induced brain injuries.

Animals ; Aspartic Acid ; analogs & derivatives ; metabolism ; Brain ; radiation effects ; Choline ; metabolism ; Male ; Proton Magnetic Resonance Spectroscopy ; methods ; Radiation Injuries ; diagnosis ; metabolism ; Rats ; Rats, Sprague-Dawley

In 1945, many Koreans, in addition to Japanese, were killed or injured by the atomic bombs dropped on Hiroshima and Nagasaki, Japan. This study compared the biological profiles of Korean atomic bomb survivors in residence at Daegu and Kyungbuk, Republic of Korea with those of a representative sample of Koreans obtained during a similar period. We evaluated anthropometric measurements, blood pressure, blood cell counts, blood chemistry, and urinalysis of survivors (n=414) and age- and sex-matched controls (n=414) recruited from the third Korea National Health and Nutrition Examination Survey conducted in 2005. Univariate analyses revealed significantly higher systolic blood pressure, white blood cell count, and serum total cholesterol, triglycerides, high-density lipoprotein-cholesterol, and aspartate aminotransferase levels (p<0.01) in the survivors. Conversely, hemoglobin concentration, hematocrit, red blood cell count, and the proportion of positive urine occult blood (p<0.01) were lower in the survivors. Our findings suggest that biological profiles of Korean atomic bomb survivors were adversely affected by radiation exposure.
Abnormalities, Radiation-Induced ; Aged ; Biological Markers/analysis ; Female ; Humans ; Japan ; Korea ; Male ; *Nuclear Warfare ; Radiation Injuries/diagnosis/*metabolism ; Radioactive Fallout ; Survivors

OBJECTIVETo understand the metabolic patterns of NAA, Cr and Cho in radiation encephalopathy (RE) induced by radiotherapy for nasopharyngeal carcinoma detected by proton magnetic resonance spectroscopy (1H-MRS), and provide useful evidence for early diagnosis of this disease.

METHODSChemical shift imaging 1H-MRS was performed for 10 healthy volunteers (control group) and 21 patients with pathologically confirmed nasopharyngeal carcinomas, who developed RE after radical radiotherapy as diagnosed on the basis of clinical symptoms and imaging findings. The contents of NAA, Cr and Cho in the pixels were observed, the metabolic maps generated, and NAA/Cr and NAA/Cho ratios calculated for all the subjects.

RESULTSThe concentrations of NAA, Cr and Cho were rarely observed in the necrosis and liquefaction foci in the patients, nor were any signals displayed on their metabolic maps. In the visible lesions, with the exception of the necrosis and liquefaction foci, the content of NAA increased slightly, whereas that of Cr or Cho decreased obviously or even became absent. An area around the lesion was identified where NAA content decreased but Cr or Cho increased. The signal in the metabolic maps appeared indistinguishable. The NAA/Cr and NAA/Cho ratios were less than 1. Farther away from the visible lesions, the NAA, Cr and Cho contents remained normal with NAA/Cr and NAA/Cho ratios of less than 1.

CONCLUSION1H-MRS is capable of displaying the patterns of metabolite changes in RE induced by radiotherapy, and identifying larger area of abnormal metabolism in RE than the visible lesion in MRI, which suggests the possibility of earlier detection of RE with 1H-MRS.

Adult ; Aged ; Aspartic Acid ; analogs & derivatives ; metabolism ; Brain Diseases ; diagnosis ; etiology ; metabolism ; Choline ; metabolism ; Creatine ; metabolism ; Female ; Humans ; Magnetic Resonance Spectroscopy ; methods ; Male ; Middle Aged ; Nasopharyngeal Neoplasms ; radiotherapy ; Radiation Injuries ; complications ; diagnosis ; Sensitivity and Specificity

OBJECTIVE: To determine the efficacy of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the detection of radiation-induced myocardial damage in beagles by comparing two pre-scan preparation protocols as well as to determine the correlation between abnormal myocardial FDG uptake and pathological findings. MATERIALS AND METHODS: The anterior myocardium of 12 beagles received radiotherapy locally with a single X-ray dose of 20 Gy. 18F-FDG cardiac PET/CT was performed at baseline and 3 months after radiation. Twelve beagles underwent two protocols before PET/CT: 12 hours of fasting (12H-F), 12H-F followed by a high-fat diet (F-HFD). Regions of interest were drawn on the irradiation and the non-irradiation fields to obtain their maximal standardized uptake values (SUVmax). Then the ratio of the SUV of the irradiation to the non-irradiation fields (INR) was computed. Histopathological changes were identified by light and electron microscopy. RESULTS: Using the 12H-F protocol, the average INRs were 1.18 +/- 0.10 and 1.41 +/- 0.18 before and after irradiation, respectively (p = 0.021). Using the F-HFD protocol, the average INRs were 0.99 +/- 0.15 and 2.54 +/- 0.43, respectively (p < 0.001). High FDG uptake in irradiation field was detected in 33.3% (4/12) of 12H-F protocol and 83.3% (10/12) of F-HFD protocol in visual analysis, respectively (p = 0.031). The pathology of the irradiated myocardium showed obvious perivascular fibrosis and changes in mitochondrial vacuoles. CONCLUSION: High FDG uptake in an irradiated field may be related with radiation-induced myocardial damage resulting from microvascular damage and mitochondrial injury. An F-HFD preparation protocol used before obtaining PET/CT can improve the sensitivity of the detection of cardiotoxicity associated with radiotherapy.
Animals ; Dogs ; Fasting ; Fluorodeoxyglucose F18/*metabolism ; Heart/*radiography ; Heart Injuries/*radiography ; Male ; Myocardium/metabolism/pathology ; Positron-Emission Tomography/*methods ; Radiation Injuries/diagnosis/*radiography ; Thoracic Neoplasms/radiotherapy ; Tomography, X-Ray Computed/*methods

OBJECTIVETo study the clinicopathologic features of delayed radiation-induced brain injury after radiotherapy for brain tumor.

METHODSThe clinical, histopathologic and immunohistochemical features of 9 cases with delayed radiation-induced injury were evaluated.

RESULTSThe disease occurred from 6 months to 12 years after radiotherapy and often presented with headache and muscle weakness. Magnetic resonance imaging showed peripheral enhancing lesions with slight mass effect and surrounding edema. Microscopically, the major changes included coagulative necrosis, fibrinoid necrosis of vessels, vascular hyalinization with luminal stenosis and peripheral reactive gliosis. Immunostaining for hypoxia-inducible factors 1α was positive in reactive astrocytes.

CONCLUSIONSDelayed radiation-induced brain injury is a relatively common complication of radiation therapy. The lesion was frequently misdiagnosed as brain tumor. Correct diagnosis relies on clinical, radiologic and pathologic correlation.

Aged ; Brain Neoplasms ; radiotherapy ; Female ; Glioma ; radiotherapy ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Radiation Injuries ; diagnosis ; diagnostic imaging ; metabolism ; pathology ; surgery ; Radiotherapy ; adverse effects ; Tomography, X-Ray Computed