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Background: Radiotherapy plays an important role in the treatment of breast cancer. In the process of radiotherapy, the underling lung tissue receives higher doses from treatment field, which led to incidence of radiation pneumonitis. Objective: The present study aims to evaluate the predictive factors of radiation pneumonitis and related changes in pulmonary function after 3D-conformal radiotherapy of breast cancer. Material and Methods: In prospective basis study, thirty-two patients with breast cancer who received radiotherapy after surgery, were followed up to 6 months. Respiratory symptoms, lung radiologic changes and pulmonary function were evaluated. Radiation pneumonitis (RP) was graded according to common terminology criteria for adverse events (CTCAE) version 3.0. Dose-volume parameters, which included percentage of lung volume receiving dose of d Gy (V5-V50) and mean lung dose (MLD), were evaluated for RP prediction. Pulmonary function evaluated by spirometry test and changes of FEV1 and FVC parameters. Results: Eight patients developed RP. Among the dose-volume parameters, V10 was associated to RP incidence. When V10

Lead-free polymer composite shields are used in diagnostic radiology to protect patients from unnecessary radiation exposure. This study aimed to examine and introduce the radiation-shielding properties of single- and multi-metal nanoparticle (NP)-based composites containing Bi, W, and Sn using Geant4, MCNPX, and XCom for radiological applications. The mass attenuation coefficients and effective atomic numbers of single- and multi-metal NP-loaded polymer composites were calculated using the Geant4 and MCNPX simulation codes for X-ray energies of 20-140 keV. The nano-sized fillers inside the polydimethylsiloxane (PDMS:C

Diabetes, which is considered as a chronic metabolic disorder leads to an increase in inflammatory cytokines and oxidative stresses. Studies have shown several functional differences in the oxidative stress and inflammatory cytokines responses in diabetic/normal cancerous patients candidate for radiotherapy. Also, radiotherapy as a cancer treatment modality is known as a carcinogen due to oxidative damage via generation of reactive oxygen metabolites and also causing inflammation of the tissue by increasing the inflammatory cytokines. Therefore, the consequence of diabetes on oxidative stress and increased inflammatory factors and synergistic effects of radiotherapy on these factors cause complications in diabetics undergoing radiotherapy. It is considered as one of the most interesting objectives to control inflammation and oxidative stress in these patients. This review aims to concentrate on the influence of factors such as MPO, MDA, IL-1β, and TNF-α in diabetic patients by emphasizing the effects related to radiation-induced toxicity and inflammation by proposing therapeutic approaches which could be helpful in reduction of the complications.

Aim: During interventional cardiology processes, patients especially women and children receive high radiation doses due to their sensitivities. In this study, we evaluated a pediatric patient dose separately in those undergone intervention cardiac procedure. Methods: In a public hospital with 252 patients, Entrance Skin Dose (ESD) and Dose-Area Product (DAP) were recorded. Prior to the beginning of fluoroscopic procedure, the chest thickness and Body Mass Index (BMI) of patients were measured. Furthermore, kV, mAs, an angle of tube and time of angiography and angioplasty were recorded. Results: Children ratio to all patients underwent the cardiovascular imaging was 1.8. The means of patients' ESD, DAP and fluoroscopy time were 178.3±17 mGy, 1123.6±11 μGym 2 and 281.4±181.2 s, respectively for coronary angiography. In coronary angioplasty, the increase in ESD, DAP and fluoroscopy times were observed. In children with congenital heart disease, ESD mean, DAP and fluoroscopy time were 24.0±9.8 mGy, 147.8±62 μGym 2 , and 552±72s, respectively. The females were 96.8 under 30 years and their dose mean was 276±37 mGy, 368±24 μGym 2 for ESD and DAP received, respectively with 376s fluoroscopy time. More than 37% of patients had (25-30) BMI. The relation between the patients’ BMI and DAP was significant ( p =0.0001). Mean mAs was 359±34 and kV was 71.23±2.7. Above all, a direct and significant correlation was found between the patients’ chest thickness with variation kV ( p =0.037, r=0.11) and mAs ( p

Recent studies have shown that the particle size of the shielding material and photon energy has significant effects on the efficiency of radiation-shielding materials. The purpose of the current study was to investigate the shielding properties of the bismuth-silicon (Bi-Si) composite containing varying percentages of micro- and nano-sized Bi particles for low-energy X-rays. Radiation composite shields composed of nano- and micro-sized Bi particles in Si-based matrix were constructed. The mass attenuation coefficients of the designed shields were experimentally assessed for diagnostic radiology energy range. In addition, the mass attenuation coefficients of the composite were comprehensively investigated using the MCNPX Monte Carlo (MC) code and XCOM. The X-ray attenuation for two different micro-sized Bi composites of radii of 50 µm and 0.50 µm showed enhancement in the range of 37-79% and 5-24%, respectively, for mono-energy photons (60-150 keV). Furthermore, the experimental and MC results indicated that nano-structured composites had higher photon attenuation properties (approximately 11-18%) than those of micro-sized samples for poly-energy X-ray photons. The amount of radiation attenuation for lower energies was more than that of higher energies. Thus, it was found that the shielding properties of composites were considerably strengthened by adding Bi nano-particles for lower energy photons.

There are various radioprotective agents with different mechanisms that help to decrease ionizing radiation side effects. The radioprotective effect of Cimetidine and IMOD was assessed individually and compared with the hybrid radioprotectors agents (HRPAs-IMOD and Cimetidine) on human lymphocyte cells.Twenty healthy volunteers (ten men and ten women) participated in the present study. About 75 mL peripheral blood lymphocytes from each individual were collected, and they were divided into 36 groups. Briefly, the blood samples were treated with different concentrations of Cimetidine (12.6 and 25.2 μg/mL) and IMOD (0.04, 0.08, and 0.12 mg/mL), and also a combination of these agents, namely hybrid radioprotectors agents (HRPAs). Besides, the irradiated groups were exposed to 2 and 4 Gy of Co-60 gamma irradiation. The amount of cellular damage was assessed using the micronucleus assay. The repeated measurements and paired T-test statistical analysis were used to compare the micronucleus frequencies in different groups.The micronucleus frequencies were significantly reduced (p 0.05) in irradiated groups when the non-toxic concentrations of Cimetidine, IMOD, and HRPAs have been used. The reduction in micronucleus frequency was obtained 5-29% for Cimetidine and 40-51% for IMOD in peripheral blood lymphocytes irradiated with 2 Gy. This reduction in 4 Gy irradiation was 8-17% for Cimetidine and 27-37% for IMOD. The HRPAs resulted in a higher radioprotective effect, in a way that they cause up to 58% and 43% micronucleus frequency reduction in 2 and 4 Gy, respectively.In conclusion, the HRPAs showed the highest level of radioprotective. In addition, IMOD was remarkably higher radioprotective than Cimetidine, which may be related to its greater non-toxic concentrations.

Nowadays, there has been a growing demand for low-dose computed tomography (LDCT) protocols. CT has a critical role in the management of the diagnosis chain of pulmonary disease, especially in lung cancer screening. There have been introduced several dose reduction methods, however, most of them are time-consuming, intricate, and vendor-based strategies that are hardly used in clinics routinely. This study aims to evaluate the image quality and pulmonary nodule detectability of LDCT protocols that are feasible and easy implemented. Image quality was analyzed in a general quality control phantom (Gammex) and then in a manmade lung phantom with nodules-equivalent objects.This study was designed in a two steps, in the first step, a feasible low-dose lung CT protocol was selected with quality assessment of accreditation phantom image. In the second step, the selected low-dose protocol with an appropriate image quality was performed on a manmade lung phantom in which there were objects equivalent to the pulmonary nodule. Finally, image quality parameters of the phantom at the appropriate scan protocol were compared with the standard protocol.A reduction of about 17% of kVp and 46% in tube current leads to dose reduction by about 70%. The contrast-to-noise ratio in the low-dose protocol remained almost unchanged. The signal-to-noise ratio in the low-dose protocol decreased by approximately 32%, and the noise level has increased by about 1.5 times. However, this reduction method hardly affected the detectability of nodules in man-made pulmonary phantom.Here, we demonstrated that the LDCT scan has an insignificant effect on the perception of lung nodules. In this study, patient dose in lung CT was reduced by modifying of kVp and mAs about approximately 70%. Hence, to step in toward low-dose strategies in medical imaging clinics, using easy-implemented and feasible low-dose strategies may be helpful.

Introduction: Near-infrared (NIR) optical imaging is a non-ionizing modality that is emerging as a diagnostic/prognostic tool for breast cancer according to NIR differentiation of hemoglobin (Hb) concentration. Methods: The transmission values of LED-sourced light at 625 nm were measured by power meter to evaluate the optical properties of Hb in breast phantom containing major and minor vessels. For the simulation of blood variations in cancerous breast condition, we prepared 2 concentrations of pre-menopausal Hb and 4 concentrations of post-menopausal Hb and, for comparison with normal tissue, one concentration of Hb injected inside the phantom's vessels. Imaging procedure on the phantom was also conducted by LED source and CCD camera. The images from the experiments were compared with the results obtained from the images analyzed by MATLAB software. Finally, mammography of phantom including various concentration of Hb was prepared. Results: The transmitting intensities of NIR in blood containing 1, 2 and 4 concentrations of Hb in the major vessels were 52.83±2.85, 43.00±3.11 and 31.17±2.27 µW, respectively, and in minor vessels containing similar Hb concentrations were 73.50±2.43, 60.08±5.09 and 42.42±4.86 µW, respectively. The gray-scale levels on the major vessel were about 96, 124, 162 and on the minor vessel about 72, 100, 130 measured for 1, 2 and 4 Hb concentrations, respectively. The sensitivity and specificity of NIR imaging differentiation were 97.4% and 91.3%, respectively. Conclusion: Significant differences in transmitting intensity, optical imaging as well as software analysis of images were observed for 1, 2 and 4 concentrations of Hb in major and minor breast phantom vessels. Differentiation capability of minor vessels was higher than major vessels for Hb concentrations. Despite a good detection for location of vessels by mammography, it could not show differences between vessels with various concentrations. However, NIR optical imaging demonstrated a good image contrast for showing vessels in terms of concentration. This study recommends NIR optical imaging for prescreening breast cancer due to its potential for early diagnosis.

Background: Application of nanomaterial has recently been introduced as a novel method to make a radiation shield to protect biological damage. Objectives: The purpose of this study was to evaluate the effectiveness regarding the use of nano-shield on the protection of the breast in chest computed tomography (CT) scan. Materials and Methods: Bismuth oxide nanoparticles were prepared and synthesized in the Chemistry Laboratory of the University of Tabriz. Special tests were used to evaluate the properties of nanoparticles. Then, nano-bismuth oxide shields were designed with the silicon matrix at 10% and 15% ratios in 0.5- and 1-mm thicknesses, respectively. The dosimetry process was performed by thermoluminescent dosimeters (TLD) dosimeters in the skin and fourth layers of the breast in the chest CT scan. Also, signals and noises of the images were obtained to assess the effects of shield on image quality. Nanoparticles size was equal to 24 nm and they were spherical in shape. The distribution of nanoparticles in the silicone matrix was approved by scanning electron microscope energy dispersive spectroscopy (SEM-EDS). Results: Nano-bismuth shields reduced the dose value by 9% and 15% in the skin layer related to 10% and 15% bismuth nanoparticles ratio (0.5 mm thickness), respectively. Also, by increasing shield thickness to 1 mm, the dose of skin layer was reduced by 18% and 24% related to 10% and 15% of bismuth nanoparticles ratio, respectively. Analysis of CT image showed a 10% increase in the noise related to the 10% bismuth shield. Conclusion: The nano-bismuth composite shield with different ratios and thicknesses show significant dose reduction in the breast. This could play a role in breast cancer prevention during chest CT scan.

Background: Bismuth shield has been recently introduced for radiation protection of patient radiosensitive organs such as breast during chest CT with image diagnosis capability. The purpose of this study was to evaluate the dose reduction and image quality conserve using new bismuth-silicon composite shields during chest CT. Materials and methods: Scans were performed on a PMMA phantom using a 6-slice MDCT system. Dose reduction was calculated by placing ion-chamber in the 12 o’clock position for breast dose measuring. Chest CT scans was performed with and without new bismuth composite shields 10% by 0.5 mm and 1 mm thicknesses. Image quality was assessed by CT numbers and noise evaluation. Results: The results of using bismuth composite shields induced to dose reduction to 7% and 12% for 0.5 mm and 1 mm thicknesses, respectively. As a result of the using 0.5 mm and 1 mm bismuth composite shields, the mean CT numbers and noise increased by a factor of 0.01 and 0.02 and also from 0.08 to 0.13, respectively. Significant dose decline was measured and no relevant noise was found. Conclusion: Results showed that new bismuth-silicon composite shields have good potential to breast dose reduction with smallest noise for diagnosis in chest CT. Keywords: Bismuth-silicon composite shield, Dose reduction, Chest CT, Image quality

Background: The main problem with coronary computed tomography angiography (CCTA) scan is the extreme exposure of patients during imaging. Bismuth belt shield is a new design to minimize the received dose in CCTA. Objectives: The purpose of this study was to design and construct new bismuth-silicon composite shields to reduce the risk of ionizing radiation during CCTA, along with an examination of the diagnostic capability of the image for the physician. Materials and Methods: Dose reduction was calculated by placing thermoluminescent dosimeters (TLDs) in skin and glandular position for breast dose measuring in the multi detector CT. CCTA scans were performed with new 10% and 15% bismuth composite shields with 1 mm and 1.5 mm thicknesses. Image quality was assessed by CT numbers and noise evaluation. Results: The breasts recorded dose without using shield were 7 - 8.90 mGy related to large or normal breasts and skin or glandular dose. The results of using 10% and 15% bismuth composite shields induced to dose reduction 9% - 31% depending on breast size, shield thickness and skin or gland position. There was a significant relationship between the reduction of breast doses and the thickness of the shields, bismuth weight percentage, the size of the breast and the dosimetry in the skin or gland. The mean noise increased from 8% to 33% in the breast position and from 4% to 25% in regions of Interest (ROIs) in locations of coronary arteries. Conclusion: The new belt bismuth-silicon shields have the potential to reduce breast dose by conserving image quality for acceptable diagnosis in CCTA.

Purpose: The biological effects of ionizing radiation (BEIR VII) report estimates that the risk of getting cancer from radiation is increased by about a third from current regulation risk levels. The propose of this study was to estimate cancer induction risk from abdominopelvic computed tomography (CT) scanning of adult patients using 6- and 16-slice CT scanners.Materials and methods: A cross-sectional study on 200 patients with abdominopelvic CT scan in 6- and 16-slice scanners was conducted. The dose-length product (DLP) and volume CT Dose Index (CTDIvol) values from the scanners as well as the effective dose values from the ImPACT CT patient dosimetry calculator with the biological effects of ionizing radiation (BEIR VII) method were used to estimate the cancer induction risk.Results: The mean (and standard deviation) values of CTDIvol and DLP were 6.9 (±1.07) mGy and 306.44 (± 60.57) mGy.cm for 6-slice, and 5.19 (±0.91) mGy and 219.7 (±49.31) mGy.cm for 16-slice scanner, respectively. The ran...

Background Mammographic density determined according paranchymal patterns is a risk factor for breast cancer and its relationships with body and other breast characteristics of women is important. The purpose of the present study was to correlate breast parenchymal patterns and mammography abnormality findings with women's BMI, compressed breast thickness (CBT) and age in Tabriz city, Iran. Materials and methods From 1,100 mammograms interpreted by radiologists, breast parenchymal was classified into four categories from Types 1 (mostly fatty) through 4 (mostly fibroglandular tissue). Age, BMI, and CBT were recorded and their relation with risk for the development of breast abnormalities in mammograms was analyzed. Results In women with a mean age of 45.8±8.63 years 17.7% were in the high density group (Type 3 and 4). A comparison of four types of breast paranchymal with BMI, CBT and age showed inverse relations to breast density. Abnormal mammographic findings were 25.8% of all reported mammograms with a circular mass (12.7%) as the most common abnormality. About 21% abnormal cases were in less than 40 years. Increasing of BMI had significant relation with breast abnormality but in CBT was not observed. Conclusions Measurement of women's body characteristics is useful for assistance in mammography diagnosis as well as selection of imaging instrument by high sensitivity for following patient in future. The effects of age, CBT and BMI groups on the breast paranchymal were significant.

The study aimed to assess the effect of bismuth (Bi) shielding on dose reduction and image quality in computed tomography (CT) through a literature review. A search was conducted in the following databases: Web of Science, PubMed, Google Scholar, and Scopus. Studies that reported estimated dose reduction with bismuth shielding during imaging of the eye, thyroid, and breast were included, and a meta-regression analysis was used to examine the influence of the CT scanner type on the dose reduction. The studies included a total of 237 patients and 34 pediatric and adult anthropomorphic phantoms for whom the radiation dose was reported. Bismuth shielding was recommended in 88.89% of the studies based on the maintenance of appropriate image quality under shielding. Noise associated with Bi shielding was 7.5%, 263%, and 23.5% for the eye, thyroid, and breast, respectively. The fixed-effects pooled estimate of dose reduction was 34% (95% CI: 13–55; p

Background Blood concentrations and oxygen saturation levels are important biomarkers for breast cancer diagnosis. Objectives In this study, the absorption coefficient of hemoglobin (Hb) was used to distinguish between normal and abnormal breast tissue. Materials and methods A near-infrared source (637 nm) was transmitted from major and minor vessels of a breast phantom containing 2×, 4× concentrations of oxy- and deoxy-Hb. The absorption coefficients were determined from spectrometer (SM) and powermeter (PM) data. Results The absorption coefficients were 0.075 ± 0.026 cm-1 for oxygenated Hb (normal) in major vessels and 0.141 ± 0.023 cm-1 at 4× concentration (abnormal) with SM, whereas the breast absorption coefficients were 0.099 ± 0.017 cm-1 for oxygenated Hb (normal) in minor vessels and 0.171 ± 0.005 cm-1 at 4× concentrations with SM. A comparison of the data obtained using a SM and a PM was not significant statistically. Conclusion The study of the absorption coefficient data of different concentrations of Hb in normal and abnormal breasts via the diffusion of near-infrared light is a valuable method and has the potential to aid in early detection of breast abnormalities with SM and PM in major and minor vessels.

This study was aimed at evaluating the mean glandular dose (MGD) and affecting factors during mammography examinations by a full-field digital mammography unit. An extensive quality control program was performed to assure that the unit is properly working. Required information including compressed breast thickness (CBT), breast parenchymal pattern and technical factors used for imaging were recorded. An entrance skin exposure measurement was also performed using slabs of polymethylmethacrylate with 2-8 cm thickness. On the basis of recorded information and measured data, the MGD was estimated for 1145 mammography examinations obtained from 298 patients. Mean CBTs of 4.9 and 5.8 cm and MGDs of 2 and 2.4 mGy were observed for craniocaudal and mediolateral oblique views, respectively. Significant correlation was seen between MGD and CBT, breast parenchymal pattern and applied kVp and mAs.

The aim of the current study was to investigate the effect of cardiologists' experience on the patient received dose during coronary angiography. The exposure parameters including fluoroscopy time, total kerma-area product (KAP), total air-kerma, fluoroscopy and cine acquisition KAP and air-kerma for five senior cardiologists with the experience of 6-10 y were recorded. The range of values for fluoroscopy time and total KAP were 2.17- 4.19 min and 12.06-21.06 Gy cm(2), respectively, in our diagnostic coronary examinations, which was below the recommended reference values. The differences among cardiologists were analysed statistically using one-way ANOVA test. The fluoroscopy KAP and air-kerma results showed statistically significant differences between cardiologists. However, the experience of the cardiologists showed no relation with patient received dose. According to the results, training in radiation protection as a requisite for interventional cardiologists was recommended.

The purpose of this investigation was to measure the patient and staff dose during routine interventional cardiology procedures for an image intensifier-based and a flat detector system using a water phantom. The Integris BH3000 image intensifier-based (Philips) and the Axiom Artis flat detector-based (Siemens) angiography units were used in this study. The accuracy of tubes potential and irradiation timers and also internal dosimeters were verified and confirmed. A water phantom with a thickness of 18 cm was used for patient and staff dose measurements. For the Philips system, phantom entrance dose rates were 2.77 and 38.97 microGym(2) s(-1) during fluoroscopy and cineangiography. The respective dose rates for the Siemens were 1.98 and 13.46 microGym(2) s(-1). Phantom entrance dose rate was 28.5 and 65% higher for the Philips system during fluoroscopy and cineangiography, respectively. Comparing the scattered dose rates at the operator location showed that the flat detector-based Siemens system delivers five times lower dose to the operator in comparison with the image intensifier-based Philips unit. The results suggest that the decrease in received dose of the patient and staff is achievable using the flat detector system. In addition, application of lead curtain and glass is recommended to lower the cardiologist dose especially for the image intensifier-based Philips system.

The dosimetric features of an unflattened 6-MV photon beam of an Elekta SL-25 linac was calculated by the Monte Carlo (MC) method.The head of the Elekta SL-25 linac was simulated using the MCNP4C MC code. The accuracy of the model was evaluated using measured dosimetric features, including depth dose values and dose profiles in a water phantom. The flattening filter was then removed, and beam dosimetric properties were calculated by the MC method and compared with those of the flattened photon beam.Our results showed a significant (twofold) increase in the dose rate for all field sizes. Also, the photon beam spectra for an unflattened beam were softer, which led to a steeper reduction in depth doses. The decrease in the out-of-field dose and increase in the contamination electrons and a buildup region dose were the other consequences of removing the flattening filter.Our study revealed that, for recent radiotherapy techniques, the use of multileaf collimators for beam shaping removing the flattening filter could offer some advantages, including an increased dose rate and decreased out-of-field dose.

Sensitivity and specificity are the two most important indicators in selection of medical imaging devices for cancer screening. Breast images taken by conventional or digital mammography, ultrasound, MRI and optical mammography were collected from 2,143,852 patients. They were then studied and compared for sensitivity and specificity results. Optical mammography had the highest sensitivity (p

Background: Application of CT- scanning image information and radiation physical characteristics of the biomaterials are two measurable assays for presenting modified cells. Objective: This study presented that CT number (HU) and linear attenuation coefficient contain useful information which can be determined during usual CT scanning for the prediction of breast cancerous cells existence based on hemoglobin concentration.Material and Methods: This experimental study used breast phantom containing major and minor vessels with diameters of 10 and 5 mm, respectively. The major vessels are filled by water, fat, hemoglobin (Hb) as a normal and 4× concentration of hemoglobin (4×Hb) as a cancerous breast cells, then scanned by single slice CT (GE, Hi Speed) 120 kVp, 100 mA for the determination of linear attenuation coefficient (µL).Results: The CT numbers were for water (-7 to +7 HU), Hb (22±6 HU) and 4×Hb (80±4 HU). The difference between Hb and 4×Hb was significant (p µL was 0.1190±0.00680 cm-1 for fat and maximum was 0.1449±0.00794 cm-1 for 4×Hb. Conclusion: The study of CT number and linear attenuation coefficient of different concentration of Hb provides a possibility for early predicting of breast cancerous cells existence (4×Hb).

Context: Radiotherapy is one of the important treatment modalities in the management of breast cancer. Aims: The aim of this study is to study the efficient treatment of breast cancer as related to the dose delivery. Materials and Methods: The human breast cancer cell lines (MCF-7) cells were cultured and exposed by 1, 2, 4, 6, 8, 10, and 20 Gy of γ-rays. Radiation-induced cell death was detected and evaluated, using three assay methods: Cell viability, clonogenic cell survival assay and induction of apoptosis. The cell viability was determined using trypan blue staining, 24 and 72 h post-irradiation. The survival fraction (SF) was determined by colony counting, 14 days after exposure and the apoptotic cell death was determined using the TUNEL assay. Statistical Analysis Used: One- or two-way analysis of variance was deemed as appropriate, followed by relevant post t-test to determine P values. Results: The difference of MCF-7 cell death through increasing post-radiation time from 24 to 72 h following the dose of 1, 6 and 10 Gy was found to be 2%, 9.6% and 7.14%, respectively. D0of MCF-7 was 220 cGy and the SF in the cells irradiated by 1 Gy and 10 Gy doses were 0.8 and 0.0001, respectively. The estimated variances were 2%, 11.1% and 8.4%, between 24 h and 72 h post-radiation apoptosis death for 1, 6, and 10 Gy, respectively. Conclusions: The dose and time dependence inducing apoptotic death was significant (P = 0.001). The delayed mortality and apoptosis was observed in MCF-7 cell, but the variance of total cell death and apoptosis in 24 and 72 h post-radiation with 6 Gy was obviously more than that with other doses.

The electrical impedance of the human urinary bladder in both benign and malignant areas can be measured using an electrical impedance spectroscopy system (EIS). Glycine is usually used in the bladder surgery in the theatre to make an insulation medium for electro-surgery and the extension of the mucosa. In addition, a saline solution is usually used to wash the inside of the bladder after bladder surgery and it is used to extend the bladder tissue mucosa. Therefore, the effect of glycine and the saline solution that fills the bladder is important, because it was expected that the application of common surface fluids (air, saline solution and glycine solution) in the bladder epithelium would affect the measured electrical impedance of the urothelium, to differentiate the malignant area from the normal bladder tissue. In this study, bladders were removed from the patients' bodies and then were moved from theatre to the histopathology department immediately after excision. These bladder samples were then opened and pinned to a corkboard to take the impedance readings, using the impedance spectroscopy system. Following this, the bladder and corkboard were completely submerged in a saline solution and readings were taken at about 1cm from the sutures. Subsequently, this procedure was repeated with the bladder submerged in glycine and then air, respectively. According to the statistical work, these fluids were found to have a significant effect on the measured impedance of the bladder tissue in benign and malignant areas. Furthermore, the best fluid between air, glycine and saline, to measure the impedance of the urinary bladder, is air (P

The reason why RBE for cell killing fell to less than unity (1.0) with very high-LET heavy-ions ((40)Ar: 1,640 keV/microm; (56)Fe: 780, 1,200, 2,000 keV/microm) was explored by evaluating the fraction of non-hit cell (time-lapse observation) and cells undergoing interphase death (calculation based on our previous data). CHO cells were exposed to 4 Gy (30% survival dose) of Ar (1,640 keV/microm) or Fe-ions (2,000 keV/microm). About 20% of all cells were judged to be non-hit, and about 10% cells survived radiation damage. About 70% cells died after dividing at least once (reproductive death) or without dividing (interphase death). RBE for reproductive (RBE[R]) and interphase (RBE[I]) death showed a similar LET dependence with maximum around 200 keV/microm. In this LET region, at 30% survival level, about 10% non-survivors underwent interphase death. The corresponding value for very high-LET Fe-ions (2,000 keV/microm) was not particularly high (approximately 15%), whereas that for X-rays was less than 3%. However, reproductive death (67%) predominated over interphase death (33%) even in regard to rather severely damaged cells (1% survival level) after exposure to Fe-ions (2,000 keV/microm). These indicate that interphase death is a type of cell death characteristic for the cells exposed to high-LET radiation and is not caused by "cellular over kill effect". Both NHF37 (non-hit fraction at 37% survival) and inactivation cross-section for reproductive death (sigma[R]) began to increase when LET exceeded 100 keV/microm. The exclusion of non-hit fraction in the calculation of surviving fraction partially prevented the fall of RBE[R] when LET exceeded 200 keV/microm. On the other hand, the mean number of lethal damage per unit dose (NLD/Gy) showed the same LET-dependent pattern as RBE[R]. These suggest that the increase in non-hit fraction and sigma[R] with an increasing LET is caused by enhanced clustering of ionization and DNA damage which lowers the energy efficiency for producing damage and RBE.

The cosmic environment is considered to include a mixture of high-energy photons and radiation particles, such as iron ions. The total radiation exposure during manned space missions contribute to heavy ions. The possibility that high Linear Energy Transfer (LET) radiation provides no ionisation within the cell target (survivor cells) and the cells with multihit events is higher due to their uniform distribution in comparison to low LET ionisation. It was explored by evaluating the fraction of survivor cells (20%) and the cells undergoing cell death (70%) in Chinese hamster ovary cells exposed to heavy ions. About 10% of the residue cells suffered from division delay and showed lethal sectoring. The Relative Biological Effectiveness (RBE) in two kinds of cell death for reproductive death and interphase death showed a similar LET dependence with a maximum of around 200 keV/µm. In this LET region, the quantity of nonsurvivor cells with reproductive death was higher than interphase death.

The bio-impedance of the urinary bladder in both benign and malignant areas can be measured using the electrical impedance spectroscopy system. In this procedure, the bladder volume changes using some liquids which were expected to affect the resulting electrical impedance of the urinary bladder (in vivo and ex vivo). Different volumes of bladders were assessed to measure their impedance using different solutions. The solution volume was changed and repeated readings were made for different volumes. Despite the measured impedance demonstrated no significant relation between the impedance and the degree of the bladder existed, but there was a little dependence between them.

Induction of interphase death was examined in Chinese hamster ovary cells exposed to accelerated heavy ions (carbon, neon, argon and iron) of various linear energy transfers (LETs) (10-2000 keV/microm). The fraction of cells that underwent interphase death was determined by observing individual cells with time-lapse photography (direct method) as well as by counting cells undergoing interphase death made visible by the addition of caffeine (indirect method). After exposure to X rays, interphase death increased linearly with dose above a threshold of about 10 Gy, whereas it increased at a higher rate without a threshold after exposure to high-LET heavy ions. The relative biological effectiveness (RBE) compared to X rays, as determined at the 50% level of induction, increased with LET, reached a maximum at an LET of approximately 230 keV/microm and then decreased with further increase in LET. The range of LET values corresponding to the maximum RBE appears to be narrower for interphase death than for reproductive death (120-230 keV/microm), as assayed using loss of colony-forming ability as a criterion. The inactivation cross section for interphase cell death reached a plateau of 5-10 microm2. This means that the probability for the induction of interphase death by traversal of a single heavy-ion track through the nucleus (size: about 130 microm2) is about 0.04-0.08.