Background: Ghrelin is a hormone related to food intake in rodents and humans, mainly produced in stomach. This study aimed to determine the effect of irradiation on ghrelin concentration in the gastric mucosa of rats. Materials and Methods : Twenty-five rats were exposed to 15 Gy of whole-abdominal irradiation. Gastric tissue samples were obtained 1, 3, 7, 30, and 90 days after irradiation. Five non-irradiated rats were used as controls. The number of ghrelin cells that reacted with anti-ghrelin antibody was counted. Moreover, ghrelin mRNA expression was determined. Food intake and body weight changes were measured simultaneously. Results: Compared to the controls, irradiated rats showed a significantly decreased gastric ghrelin cell count, i.e., 29%, 30%, 32%, and 32% at 1, 3, 30, and 90 days, respectively, after irradiation (p < 0.05). Irradiated rats also showed decreased ghrelin mRNA expression the expression decreased by 54.1%, 58.8%, 52.0%, and 52.7% at 1, 3, 30, and 90 days, respectively (p < 0.05). Food intake of irradiated rats decreased continuously compared with the control rats, except at 90 days. Body weight of the irradiated rats was lower than that of the controls at 7 and 30 days. Conclusion: This study demonstrated that abdominal irradiation can reduce gastric ghrelin concentration. Though decrease of food intake and body weight was observed simultaneously, further evaluation needs to find out the relationship between gastric ghrelin level and food intake after exposure to irradiation.

Background: To determine which radiotherapy parameters are associated with the tumor response of locally advanced non-small cell lung cancer (NSCLC) patients undergoing concurrent chemoradiotherapy. Materials and Methods: Thirty one patients with IIIA/IIIB NSCLC underwent chemoradiotherapy with a median dose of 63 Gy. On our actual treatments, we made radiotherapy planning to cover the planning target volume (PTV) with 95% of the prescribed dose, and checked the second CT simulation when a cumulative dose was about 36 Gy. For this study, each PTV of primary tumor was re-defined with even margins from the gross target volume (GTV), and the actual plan overlaid the re-defined PTV. The correlations between the tumor response rate during chemoradiotherapy and after chemoradiotherapy, and the dose distribution parameters (D95, V95, mean tumor dose and homogeneity index), total dose and GTV, were evaluated. Results: Median overall survival was 15.5 months and the two-year survival 42.3%. At first recurrence, radiation-field recurrence, distant metastases and simultaneous recurrence were developed in 35.5%, 41.9% and 9.7% of the cases, respectively. The dose distribution parameters were generally favorable and were not related with tumor response rate. The tumor response rate after chemoradiotherapy was correlated with the residual GTV at second simulation (&gamma=-0.627, p<0.001) and the tumor response rate during chemoradiotherapy (&gamma=0.541, p=0.003). Conclusion: Minimal correlation was found between the dose distribution parameters that were over the minimal dose requirement and tumor response in NSCLC with concurrent chemoradiotherapy. The small residual volume during chemoradiotherapy could indicate good tumor response after chemoradiotherapy.

Background: This study assessed the clinical usefulness of the solid phantom, which may compensate for the disadvantages of the water phantom, by comparing the radiological doses between the two depending on their depths. Materials and Methods: The experimental equipment used was a linear accelerator for medical use, water phantom, solid phantom, Farmer type ion chamber and electrometer. The distance between the ray source and the center of the ion chamber was fixed to a SAD of 100 cm during the experiment. The field size was 10 x 10 cm2 and the radiation energies of the photon rays were 6 MV and 15 MV. The depth interval was 1cm (range 1-10 cm) for each energy. The relative deviation ratio of the water phantom to the solid phantom was calculated. Results: The measurement at 100 MU was performed more than five times to calculate the average charge and absorbed dose, and the relative deviation was analyzed based on the water phantom. The results obtained at depths from 1 to 10 cm were 0.034%, -0.457%, -0.167%, 0.011%, 0.117%, 0.271%, 0.349%, 0.709%, 0.376% and 0.611% at 6 MV and those obtained at 15 MV were 1.199%, 0.033%, 0.166%, 0.496%, 0.556%, 0.705%, 0.656%, 1.071%, 0.7% and 1.057%, respectively. Conclusion: In conclusion, the solid phantom is useful and may complement the disadvantages of the water phantom, including the time required for its installation and errors in the measurement depth, and may precisely measure the radiological dose.

Background: The trabecular bone changes in the tibia of C₃H/HeN mice were measured 12 weeks after whole body irradiation with various doses of fast neutrons (0-2.4 Gy) or ¹³⁷Cs-generated gamma-rays (0-6 Gy). Materials and Methods: Serum calcium, phosphorus, estradiol concentration and alkaline phosphatase activity were measured. Tibiae were analyzed using microcomputed tomography. Biomechanical property and osteoclast surface level were measured. Results: There was a significant relationship between the loss of bone architecture and the radiation dose, and the best-fitting dose-response curves were linear-quadratic. Mean relative biological effectiveness (RBE) values (Ref. gamma) of 2.05 and 2.33 were estimated for fast neutron irradiation in trabecular bone volume fraction and bone mineral density, respectively. There was a substantial reduction in osteoclast surface level in tartrate-resistant acid phosphatase-stained histological sections of tibial metaphyses in irradiated mice with high dose of neutrons. Conclusion: There was a significant relationship between the loss of bone architecture and the radiation dose. The difference of osteoclastic bone resorption may represent a contributor to the low RBE in high dose of irradiation level relative to that of low dose level.

Background: Radiation-induced molecular changes on the endothelial surface of brain arteriovenous malformations (AVM) may be used as markers for specific vascular targeting agents. In this study, we examined the level of expression of platelet endothelial cell adhesion molecule-1 (PECAM-1) on brain endothelial cell surface after radiation treatment, with the aim of targeting the radiation-induced PECAM-1 on the AVM endothelium with pro-thrombotic agents to selectively occlude AVM vessels. Materials and Methods: Mouse cerebral endothelial cells (bEnd.3) were irradiated with 5, 15, or 25 Gy. Real-time quantitative polymerase chain reaction (PCR) and in-cell enzyme-linked immunosorbent assay (ELISA) were performed to quantify the temporal gene and surface PECAM-1 protein expression up to 168 hours post-irradiation. Two-tailed unpaired t-tests were used to determine statistical significance. Results: PECAM-1 gene expression was found to be significantly elevated post-irradiation in real-time quantitative PCR, with the maximum level of gene expression being evident at 120 hours post-irradiation representing an 11-fold increase in comparison to non-irradiated controls (p<0.001). In-cell ELISA detected a similar up-regulation for protein expression on the cell surface with delayed peak time. Conclusion: Ionising radiation can induce the up-regulation of PECAM-1 on brain endothelial cell surface. This protein may be a potential candidate for facilitating selective AVM vessel occlusion through the application of radiosurgery followed by vascular targeting.

Background: Dose calculation algorithms play a very important role in predicting the explicit dose distribution. We evaluated the percent depth dose (PDD), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calculation algorithms and inhomogeneity correction methods. Materials and Methods: The homogeneous and inhomogeneous virtual slab phantoms used in this study were manufactured in the radiation treatment planning system to represent the air, lung, and bone density with planned radiation treatment of 6 MV photons, a field size of 10 × 10 cm², and a source-to-surface distance of 100 cm. Results: The PDD of air density slab for the Acuros XB (AXB) algorithm was differed by an average of 20% in comparison with other algorithms. Rebuild up occurred in the region below the air density slab (10–10.6 cm) for the AXB algorithm. The lateral dose profiles for the air density slab showed relatively large differences (over 30%) in the field. There were large differences (20.0%–26.1%) at the second homogeneous–inhomogeneous junction (depth of 10 cm) in the field for all calculation methods. The surface dose volume histogram for the pencil beam algorithm showed a response that was approximately 4% lower than that for the AXB algorithm. Conclusion: The dose calculation uncertainties were shown to change at the interface between different densities and in varied densities using the dose calculation methods. In particular, the AXB algorithm showed large differences in and out of the field in inhomogeneous media.

Background: Fatigue is a common side effect in cancer patients undergoing radiation therapy (RT). Radiation-induced fatigue affects the quality of life, but there is no definitive treatment option. In this study, the weight-loaded forced swim test was performed to assess the effect of coenzyme Q10 (CoQ10) on radiation-induced fatigue. Materials and Methods: A total of 60 rats were divided randomly and equally into four groups: No swim, No RT, RT + placebo, or RT + CoQ10. The No swim, No RT, and RT + placebo groups received 1 mL of soybean oil daily for 14 days. The RT + CoQ10 group received 100 mg/kg of CoQ10 in soybean oil at the same times. Both RT groups were irradiated with 10 Gy on the 14th day of treatment. The swim test with sinkers weighing 10% of body weight was performed 24 h later in all animals except the No swim group. Results: The level of blood urea nitrogen (BUN) was significantly lower in the No swim than the other groups. The BUN level of the No RT group was significantly decreased compared with the RT + placebo group, but it did not differ from the RT + CoQ10 group. Swimming times to complete exhaustion were significantly longer in the No RT and RT + CoQ10 groups compared to the RT + placebo group (99.4, 105.9, and 75.7 s, respectively) (P<0.001). Conclusion: Supplementation with CoQ10 can prevent the decrease in endurance capacity caused by radiation.  

Background: In response to the need for diagnosis and treatment, medical radiation has been increasingly used worldwide. This study investigated the medical utilization of radiation-related diseases among radiological technologists (RTs) and factors that influence such diseases. Materials and Methods: Data were collected from the Taiwan National Health Insurance Research Database. A panel study was conducted with a sample of 3,432 RTs obtained in 2007 and followed up until 2011. Logistic regression applying generalized estimating equations was used for investigating the relationship between RTs and radiation-related diseases. Results: Among the RTs, the annual medical utilization rate of hospitalization for radiation-related neoplasms was 1.17‰-4.43‰, that for circulatory diseases was 4.68‰-11.50‰, and the annual medical utilization rate of outpatient visits for cataracts was 2.91‰-7.38‰. After sex, age, hospital accreditation level, and hospital ownership were controlled, the odds of hospitalization for neoplasms and circulatory diseases among the RTs were nonsignificantly higher than those of pharmacists, and the odds of outpatient visits for cataracts among the RTs were nonsignificantly lower than those of pharmacists. Conclusion: No sufficient evidence exists to substantiate the argument that the exposure of RTs to current doses of radiation could increase the risk of neoplasms, circulatory diseases, and cataracts. Considering the increased use of radiation treatment in current medical facilities, all speculation on occupational radiation-induced diseases must be further investigated and verified.

4-Methylimidazole (4-MEI) is a simple nitrogen-containing heterocyclic compound, and recently classified as group 2B by International Agency for Research on Cancer (IARC). Caramel coloring is widely applied food coloring in many food products including coffee, carbonated beverages, beer and wine. In present study, ɣ-irradiation was applied to Caramel Color III to reduce the level of 4-MEI without color changes. Caramel coloring III was ɣ-irradiated with 1, 3, 5, 10, 30, 50 and 100 kGy. Non-irradiated caramel coloring was served as a control. The level of 4-MEI and color were analyzed on all caramel coloring. The concentration of 4-MEI in the non-irradiated caramel coloring was 714.9 mg/kg. The level of 4-MEI in caramel coloring was significantly reduced from 3 kGy ɣ-irradiated caramel coloring (p<0.05). After 100 kGy irradiation, the amount of 4-MEI in caramel color was at 658 mg/kg, which equates 7.9% reduction from non-irradiated sample. No color change was observed on irradiated and non-irradiated caramel coloring (p>0.05). Therefore, ɣ-irradiation could be used as an alternative processing method to improve the quality of caramel coloring by reducing 4-MEI content without its color change.

Background: This study was conducted to assess the accuracy of dose calculation near the air-phantom interface of a heterogeneous phantom for Acuros XB (AXB) and Anisotropic Analytical Algorithm (AAA) algorithm of a           6-MV flattening-filter-free beam, compared with film measurements. Materials and Methods: A phantom included air gap was specially manufactured for this study. In order to evaluate the dose near air gap-phantom interface, Eclipse treatment planning system equipped both AXB and AAA was used for the dose calculations. Measurements in this region were performed with radiochromic film. The central-axis dose (CAD) and off-axis dose (OAD) between calculations and measurements were analyzed for various field sizes and air gaps. The root-mean-square-error (RMSE) was used to evaluate the difference between the calculated and measured OAD. In order to quantify agreement between the calculated and measured dose distributions, the gamma analysis was performed with the 2%/2 mm and 3%/3 mm criteria. Results: For all fields traveling through 1 and 3 cm air gap, the maximum difference in the calculated CAD was -5.3% for AXB and 214.8% for AAA, compared to the measured CAD. For the RMSE between the calculated and measured OAD, the calculated OAD using AXB showed interval in the RMSE (from 4.4 to 12.7) while using AAA indicated broad (from 7.7 to 101.0). In addition, the gamma passing rates showed that AXB was higher agreement than AAA. Conclusion: This study demonstrated that AXB was more accurate in heterogeneous media near air-phantom interface than AAA when comparing the measured data.