International Journal of Radiation Research
Year:2018 | Volume:16 | Issue:2|Papers Count:12

With the development of science and technology, microwave has been used in many fields such as industry, military, medicine and communica on. People are living in a lapped and dynamic electromagne c environment. Concerns about poten al hazards of microwave are ge ng increasing a en ons. The single biological effects of microwave were widely discussed which was considered harmful. Relevant safety standards had been formulated and applied. However, the real environment was more complex. Microwave was not the only factor that organisms might be affected. Other physical or chemical factors, such as ionizing radia on (IR), ultraviolet (UV), magne c field and chemical drugs, o-en existed with the microwave radia on. Even the microwave itself could create combined exposure situa on, because the environment consisted different frequency microwaves. Nuclear weapons and high-power radar could produce microwave and ionizing radia on. The ultraviolet ray and magne c field generated by the instrument's opera on could act on the human bodies along with the microwaves. The combina on of radiofrequency therapy and chemotherapeu c agents was also commonly used in cancer therapy. Therefore, the combined biological effects of microwaves and other physical or chemical factors were very important. This review had covered the original ar cles in this aspect. In order to be er understand the combined biological effects, the compara ve studies of different frequency microwaves were also included. Differences in biological effects were found among different frequency microwaves, and the combined biological effects contained both hazards and benefits. Findings in combined biological effects were very prac cal for ra onal uses of microwave technologies.

Background: The hematopoie c system is sensi ve to the adverse effects of ionizing radia on. Cellular therapies u lizing mesenchymal stem cells or vascular endothelial cells have been explored as poten al countermeasures for radia on hematopoie c injuries. We inves gated cells cultured from amnion (Amnion-derived Mul potent Progenitor cells, AMPs) for effects on hematopoie c recovery following total body irradia on in mice. Materials and Methods: C57BL/6J mice were sham-irradiated or exposed to 60Co irradia on (7. 75 – 7. 90 Gy, 0. 6 Gy/min). Either AMPs (5 × 106 cells/animal) or vehicle were administered 24 h pos rradia on via intraperitoneal injec on. Results: We observed a 13% and 20% improvement in 30-day survival of mice treated with AMPs compared with treatment with vehicle following irradia on at 7. 75 and 7. 90 Gy, respec vely. AMP treatment was characterized by a trend toward accelerated recovery of white blood cells, neutrophils, re culocytes, and monocytes, measured through day 40 pos rradia on a9er 7. 75 Gy. AMP treatment enhanced hematopoie c cell repopula on of spleen and femoral bone marrow as measured by total nucleated cell and hematopoie c progenitor cell counts in comparison to vehicle-treated animals. FACS analysis showed that AMPs treatment significantly mi gated the reduc on in CD11b+/Gr-1int and CD11b+/Gr-1high bone marrow cell popula ons at the nadir, and improved recovery of these cell types. Conclusion: Together, our data indicate that AMPs reduced hematopoie c toxicity induced by ionizing radia on when infused within 24 h a9er radia on injury.

Background: The aim was to evaluate the benefit of technical advances for treatment planning: introduc on of a hydrogel spacer, VMAT (volumetric modulated arc therapy) and a single biological organ at risk objec ve for the rectum and bladder. Ini al standard was a step-and-shoot IMRT (intensity modulated radiotherapy) without a spacer and conven onal organ at risk objec ves. Materials and Methods: Treatment plans were calculated using IMRT and VMAT techniques before and a(er spacer injec on in 27 pa ents, respec vely. Conven onal organ at risk objec ves have been used for the op miza on of IMRT plans, only a single biological organ at risk objec ve for VMAT plans. VMAT vs. IMRT plans and plans before vs. a(er spacer injec on were compared. Results: VMAT plans and independently the spacer demonstrated improved dose homogeneity, whereas VMAT addi onally displayed improved dose conformity. The dose to the bladder and rectum could be significantly decreased applying the VMAT technique (mean rectum volumes of 14%/10%/5% in VMAT vs. 36%/24%/12% in IMRT within the 50Gy/60Gy/70Gy isodoses; p<0. 01). NTCP for ≥ grade 3 rectum toxicity could be accordingly decreased with the VMAT technique (3. 6 vs. 0. 9% for IMRT vs. VMAT; p<0. 01) and the spacer gel (3. 3 vs. 1. 2% for plans without vs. with spacer gel; p<0. 01) – only 0. 3% with VMAT and spacer gel. Conclusion: In addi on to the decreased rectal dose following spacer injec on, VMAT with single biological organ at risk op miza on resulted in further dose reduc on to the organs at risk and improved dose homogeneity and conformity in comparison to the step-and-shoot IMRT technique with conven onal objec ves.

Background: This study was performed to assess pa ent survival and treatment toxicity a er helical tomotherapy (HT) with simultaneous integrated boost (SIB) radiotherapy (RT) for cancer pa ents with one to eight brain metastases (BM) who have been treated with or without surgery. Materials and Methods: A total of 48 brain metastasis (BM) pa ents were included in this retrospec ve study between April 2015 and December 2016, . The pa ents were treated with image-guided intensity modulated radia on therapy (IMRT) on the helical tomotherapy (HT) machine. Whole brain HT as 25 Gy and SIB to metastasis sites as 35 Gy was delivered in 10 frac ons. The pa ent were aged between 50 to 80 years old, volume of the BM was between 6 to 75 cc and the number of brain metastasis was between 1 to 8, Karnofsky Performance Score (KPS) ranged between 50-90 and RPA I-III. Surgery was performed to two pa ents before RT. The maximum pa ent follow-up  me was 20 months. Results: The primary neurotoxicity observed in pa ents was grade I-II brain edema related headache and lethargy. In pa ents who had survived 3-12 months, KPS improved median score of 20 points and RPA was grade I a er six months. Twelve pa ents had passed away at the end of a 20-month follow-up. Conclusion: HT u lizing SIB treatment for 1-8 BM was achieved successfully with no significant toxicity. An improvement of performance status indicators of pa ents following RT was observed.

Background: Due to limited clinical data in pediatric-type sarcomas (rhabdomyosarcoma, Ewing's sarcoma, PNET, and desmoplas c small round-cell tumor), the aim of this study was to evaluate the demographic characteris cs and iden fying prognos c factors for survival. Materials and Methods: We retrospec vely reviewed 110 pa ents with pediatric-type sarcomas. Overall and disease free survival was analyzed with the Kaplan-Meier method and log rank test. To iden fy prognos c factors for overall and disease free survival, mul variate survival analyses using a Cox’ s propor onal-hazard regression model was performed. Results: In this study mean age of pa ents were 20. 30 years (SD=13. 61; range, 1– 83 years). The survival data of 54 pa ents (49. 1%) were obtained with median survival of 27 months. 3 and 5-year survival rate of these pa ents were 41. 5% and 28. 3% respec vely. Recurrence of disease (P=0. 006) and Ewing sarcoma subtype (P=0. 018) were significantly associated with poor overall survival and loca on of the lesion in the upper extremi es (P=0. 007) and trunk (P=0. 005) were significantly associated with a lower disease free survival. Conclusion: With mul variate analysis, the authors determined that recurrence of disease and Ewing's sarcoma subtype are poor prognos c factors for overall survival and site of origin for disease free survival among pa ents with pediatric-type sarcoma. In addi on, gender, pa ent's age, and size of tumor had no significant impact on overall and disease free survival.

Background: Recently, the Fla ening Filter Free (FFF) beams, which allow a dose rate increase of up to four  mes compared to the normal dose rate, have been incorporated into radia on therapy machines. The aim of this study is to evaluate an tumor ac vity in hypoxic cells irradiated with different dose rates using FFF beams and to iden fy the casual mechanism for cellular damage during irradia on. Materials and Methods: EMT6 cells were treated with 95% N2 and 5% CO2 to maintain a hypoxic condi on. Three dose rates, namely, 6. 27 Gy/min, 12. 00 Gy/ min, and 18. 82 Gy/min, were used to deliver the prescribed dose of 2 to 4 Gy using the TrueBeam linear accelerator. The number of colonies was counted to evaluate the cell surviving frac on. To inves gate the mode of ac on, addi onal experiments to detect reac ve oxygen species (ROS) by aminophenyl fluorescein (APF) assay, and DNA double-strand breaks (DSBs) by γ H2AX assay were performed. Results: Irradia on of hypoxic cells using FFF beams increases an tumor ac vity as a func on of dose rate. The fluorescence of the APF assay was significantly increased when high dose rates were used. In addi on, results from our γ H2AX assays show that the number of DNA DSBs increased as a func on of dose rate, in hypoxic cells. Conclusion: We demonstrate that there is a significant dose rate-dependent difference in an tumor ac vity in hypoxic cells, when FFF beams are used.

Background: The new glasses from harmful environmental waste such as cement dust; limestone phosphate, sand and borax (Genkare) were manufactured. Inves ga on of the radioac vity present in these materials (Phosphate rock, cement dust, limestone, sand and borax) enables one to assess any possible radiological hazard to humankind by such materials. Materials and Methods: Fi%een samples were collected from five loca ons. Ac vity measurements have been performed by gamma-ray spectrometer, employing a high-resolu on scin lla on detector NaI (Tl) crystal 3 ×3 inch. In addi on, the radiological hazards were calculated for the inves gated samples. Results: The average values of ac vity ranged from 28± 2 to 163± 12, 2. 8± 0. 7 to 40± 3 and from 49± 4 to 1337± 74 Bq kg-1 for 226R, 232Th and 40K, respec vely. The values of absorbed dose rates, radium equivalent ac vi es and annual effec ve dose due to 226Ra, 232Th and 40K respec vely, are ranged from 22. 05 to 101. 59 nGy h-1, 45. 90 to 224. 22 Bq kg-1 and 27. 04 to 124. 59 μ Sv y-1. In addi on, the values of external hazard index, internal hazard index and gamma index have been calculated. Conclusion: According to the obtained results, all materials would not present a significant radiological hazard except phosphate. The results of the study could serve as important baseline radiometric data for future epidemiological studies and monitoring ini a ves.

Background: Radio frequency wave (RFW) generated by mobile phones and wireless communica on systems has been reported to cause adverse effects on reproduc ve func on, vision and hematological parameters, possibly through oxida ve stress. The aim of this study was to evaluate the effect of RFW generated bybase transceiver sta on BTS on oxida ve stress in tes s, eye and erythrocyte, and the prophylac c effect of vitamin E by measuring the an oxidant enzymes ac vity, including: glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), and lipid proxida on. Materials and Methods: Thirty-two adult male Sprague– Dawley rats were randomly divided into four groups and treated daily for 45 days as follows: control, treatment control (vitamin E 200 mg/kg of body weight/ day by gavage), sham exposed group (exposed to 900 MHz RFW), and treatment group (received vitamin E and exposed to RFW). Control and treatment control groups were not exposed and were only given the vehicle, i. e., dis lled water. On the last day of the study, all the rats were sacrificed and their testes, eyes and erythrocyte were collected and used for measurement of an oxidant enzymes ac vity and lipid peroxida on. Results: Exposure to RFW in the sham exposed group decreased an oxidant enzymes ac vity and increased lipid peroxida on compared to both control groups (p<0. 05). In the treatment group, vitamin E improved an oxidant enzymes ac vity and reduced lipid peroxida on compared to the sham exposed group (p<0. 05). Conclusion: RFW causes oxida ve stress in eye, tes s and erythrocytes and vitamin E improved oxida ve stress in these  ssues.

Background: Prospec vely electrocardiography (ECG)-triggered high-pitch spiral coronary computed tomography angiography (CCTA) is a unique scan mode for dual-source CT (DSCT). Our reports aim to compare image quality and radia on dose of CCTA using high-pitch spiral or sequen al acquisi on mode in pa ents with low and stable heart rates. Materials and Methods: Pa ents with low and stable heart rates (HR) (HR ≤ 70 beats per minute [bpm]; heart rate variability [HRV] < 10 bpm) were randomly assigned to high-pitch spiral mode (group A; n = 80) or sequen al acquisi on mode (group B; n = 80). Image quality scores, image noise, effec ve radia on dose and influencing factors on image quality were assessed. Results: Mean image quality scores were 1. 51 ± 0. 32 and 1. 70 ± 0. 38 for groups A and B (P < 0. 05), respec vely. Image noises of the two groups were 19. 05± 4. 70 Hu and 27. 21± 8. 88 Hu (P < 0. 05). Contrast media cost in group A was lower than group B (P < 0. 05). No sta s cal difference was found in the rate of diagnos c pa ents between the two groups (P = 0. 416). The es mated radia on dose of group A was 26. 0% reduced compared with group B (0. 74 ± 0. 34 mSv vs. 1. 00 ± 0. 48 mSv, P < 0. 05). Conclusion: In pa ents with regular and low heart rates, the prospec vely high-pitch spiral acquisi on mode can reduce radia on dose and contrast media cost while maintaining image quality compared with the prospec vely sequen al mode.

Background: Mul ple beams are generally used with an increased possibility that the beam axis intersects the treatment table. Treatment tabletops are commonly made of carbon fiber due to its high mechanical strength and rigidity, low specific density, extremely light and low radia on beam a enua on proper es. Purpose of this paper is inves gated the dose changes in the buildup region and beam a enua on by a carbon fiber tabletop for high energy 6-and 18-MV photon beams. Materials and Methods: Measurements were performed for 10 cm × 10 cm and 20 cm × 20 cm field sizes. The surface dose and percentage depth doses (%DD) were measured by a Markus parallel plate chamber at a source-surface distance (SSD) of 100 cm for 6 MV and 18 MV photon beams. A enua on measurements were made at the solid-water phantom for gantry angles of 0o and 180o rota on of the beam. Results: A carbon fiber tabletop increases the surface dose from 12. 87% to 86. 65% for 10 cm x 10 cm and from 8. 72% to 71. 16% for 20 cm × 20 cm field at 6 and 18 MV, respec vely. The surface dose with the carbon fiber tabletop in an open field (0o) increases with field size. Conclusion: The carbon fiber tabletop causes a substan ally increased surface dose, and also significantly decreases the skin-sparing effect, which is clinically important. The dosimetric effect of the tabletop may be higher, especially for the intensitymodulated radia on therapy depending on the beam orienta on.

Background: This study was designed to suggest the possibility of hormone-related derangement in salvage radiotherapy (SRT) a er radical prostatectomy in terms of prostate-specific an gen (PSA) control. Materials and Methods: Among 160 consecu ve prostate cancer pa ents who received radical prostatectomy, 34 with SRT between 2004 and 2012 were retrospec vely reviewed. The numbers of pa ents with pathologic T3-T4 stage, Gleason score 8-10, and posi ve resec on margin were 11 (32. 4%), 10 (29. 4%), and 17 (50. 0%), respec vely. Median SRT dose was 64. 8 Gy (range, 52. 9-70. 0 Gy) with 1. 8-2. 3 Gy frac ona ons. Biochemical failure-free survival a er SRT was counted and the median follow-up period was 32. 5 months (range, 10-118 months). Results: A er SRT, the median  me for PSA to decrease to less than 0. 2 ng/mL was four months (range, 0-25 months). The three-year survival rate was 60. 3%. On univariate analysis, preferen al hormone therapy (PHT) (p=0. 022), higher PSA at SRT (p=0. 005), and higher PSA a er surgery (p=0. 003) were related to a shorter biochemical survival period. On mul variate analysis, lower PSA at SRT (p=0. 016), higher radia on dose (p=0. 007), and non-PHT (p=0. 046) suggested a consistent PSA control. Conclusion: According to these results, low PSA values by hormonal interven on need to be reconsidered with a different way to look at the rela onship between the PSA and hormone therapy. SRT should be considered for postopera ve salvage treatment regardless of the hormone-related PSA values.

Background: Prognosis and management of breast cancer are defined by different variables including histological type, grading, clinical stage, Her2+, estrogen and progesterone receptor condi ons. Generally, mammography is one of the most important imaging which is done in breast cancer pa ents. The aim of this research was to evaluate different mammographic pa"erns in different breast cancer sub types. Materials and Methods: Demographic and clinicopathologic data of 128 breast cancer pa ents which referred to two academic hospitals were obtained from their registered files and their mammographies were reviewed by two radiologists separately. Pa ents were categorized into 3 groups of Luminal, triple nega ve and Her2+ and the checklists were filled out by research team. The men oned data was then analyzed by the SPSS so+ware version 16. Results: In this study we found significant difference in margins' clarity and axillary lymphadenopathy between mammographic presenta ons of different breast cancer subtypes (P=0. 041) and (P=0. 14), respec vely; but the difference of other mamographic presenta ons including mass existence, mass size, margin type, peleomorphic calcifica on, micro calcifica on, nipple retrac on, skin thickening and  ssue distor on were not significantly different between three groups (P>0. 05). Conclusion: Results of current study showed no significant difference between mammographic features of different invasive breast cancer subtypes except for axillary lymphadenopathy and ill-defined margins. Since the majority of pa ents were in premenopausal status; perhaps we can say lower sensi vity of mammography in premenopausal women couldn’ t accurately dis nguish mammographic differences between invasive breast cancer subtypes in this study.