International Journal of Radiation Research
Volume:14 Issue: 2, Apr 2016

Aim of this study is to evaluate the accuracy of the gated volumetric modulated arc therapy (VMAT/RapidArc) using 2D planar dosimetry, DynaLog files and COMPASS 3D dosimetry system.
Pre-treatment quality assurance of 10 gated VMAT plans was verified using 2D array and COMPASS 3D dosimetry system. Advantage of COMPASS over 2D planar is that it provides the clinical consequence of error in treatment delivery. Measurements were performed for non-gated and different phase gating window level (80%, 50%, 30% & 20%) to know the impact of gating in VMAT dose delivery.
In 2D planar dosimetry, gamma agreement index (GAI) for all measurements were more than 95%. DynaLog file analysis shows the average deviations between actual and expected positions of monitor units, gantry and multi-leaf collimator. The STDVs MU and gantry position were less than 0.10 MU and 0.33° respectively. Root mean square (RMS) of the deviations of all leaves were less than 0.58 mm. The results from COMPASS show that 3D dose volume parameters for ten patients measured for different phase gating window level were within the tolerance level of ±5%. Average 3D gamma of PTV and OAR’s for different window level was less than 0.6.
The results from this study show that gated VMAT delivery provided dose distributions equivalent to non-gated delivery to within clinically acceptable limits and COMPASS along with MatrixEvolution can be effectively used for pretreatment verification of gated VMAT plans.

Local ablative treatments play an important role for patients who cannot be treated surgically. Radiofrequency ablation is a well-established alternative to surgical treatment of thyroid nodules, however it also has disadvantages. Microwave ablation (MWA) is a new minimally invasive treatment promising several improvements. The aim of this retrospective study was to evaluate the effects of microwave ablation on thyroid nodules by 99mTc-pertechnetate and 99mTc-MIBI scintigraphy.
30 patients with overall 40 nodules were treated. For the ablation of thyroid nodules, a microwave generator working with frequencies from 902 to 928 MHz was used. The ablation time ranged between 120 and 300 seconds per ablation zone. The target temperatures ranged between 60-80 °C. Pre- and post- interventional, the radionuclide uptake was determined using a thyroid specific scintillation camera. For 27 cold nodules 99mTc-MIBI was used for evaluation; 13 indifferent nodules were measured with 99mTc-pertechnetate.
The relative change of uptake was detected as a quotient of pre- and post- therapeutic uptake. The statistical analysis of scintigraphy data proved the efficacy of microwave ablation. 99mTc-pertechnetate scintigraphy showed an uptake reduction of 39% (range 9 to 85%). 99mTc-MIBI imaging showed a median reduction of 40% (p The determined results show the effectiveness of MWA as a treatment option for benign thyroid nodules. With functional scintigraphy a significant activity decrease could be detected in the ablation zone; hence a verification of affectivity was possible after a short period of time.

Radiation absorbed dose to the red bone marrow, a critical organ in the therapy of thyroid carcinoma, is generally kept below 2 Gy for non-myeloablative therapies. The aim of this study was to calculate bone marrow radiation dose by using MIRDOSE3 package program and to optimize the safe limit of activity to be administered to the thyroid cancer patients.
In this study, 83 thyroid cancer patients were divided into 3 groups based on the amount of activity administered into the body. In the groups, 3700 MBq, 5550 MBq and 7400 MBq activities were used respectively. The curves of time-activity were drawn from blood samples counts and effective half-life and residence time were calculated. Correlations of bone marrow radiation dose and radioiodine effective half-life were determined as a function of administered activity via ANOVA test. Tg levels and tumour diameters were compared using Spearman’s correlation.
The effective half-lives of 131I for three groups of whole-body, receiving 3700 MBq, 5550 MBq and 7400 MBq were calculated as 20.57±5.4, 17.8±5.8 and 18.7±3.9 hours, respectively. The average bone marrow doses for 3 groups of patients were 0.32±0.08 Gy, 0.42±0.14 Gy and 0.60±0.24 Gy, respectively.
It was concluded that, the bone marrow dose to the patients still remains within the recommended level even after administering an activity of 7400 MBq of 131I to the patients.

The variation of the radon progeny concentration in outdoor environment and meteorological parameters at fine resolution were studied for one year at a continental location, National Atmospheric Research Laboratory, Gadanki, India.
The concentrations were measured using Alpha Progeny Meter by collecting air samples at a height of 1 m above the Earth’s surface at a known flow rate.
Radon progeny concentration shows temporal variations on diurnal and monthly scales, and is due to mixing in the atmosphere. Peak in the early morning hours and low values during afternoon compared to nighttime are due to differential heat contrast between earth’s surface and its atmosphere. However, the activity during February shows maximum compared to June/July months. The diurnal variation of radon progeny shows positive correlation with the relative humidity and negative correlation with ambient temperature. The monthly mean activity of radon progeny for the year 2012 was found to be 4.76 ± 0.73 mWL.
The mean concentration of radon progeny in the study region is relatively high compared to the other locations in India and may be due to the rocky terrains and trapping of air-masses near the observation site due to its topography.

Hydrogen has been demonstrated can selectively reduce the hydroxyl, which is the main cause of ionizing radiation-induced damage. Amifostine (AM) is the only radioprotective drug approved by the U.S. Food and Drug Administration for use in radiotherapy. The purpose of the present study was to investigate the combined radio-protective effect of hydrogen rich water (HRW) and AM.
Male ICR mice were treated intragastrically with HRW or/and intraperitoneally with AM 30 minutes prior to 9.0 Gy whole body irradiation from a 60Co source (dose rate 0.96Gy/min). Then the survival rate for 30 days, the hematological parameters, the Clinical chemistry parameters and the bone marrow nucleated cells were examined.
We found that the mice treated with HRW and AM before irradiation could increase the 30-day survival rate and improve the body weight better than the HRW or AM treatment alone group and irradiation alone group. Hematological test and Clinical chemistry assays also showed the same results that HRW combined AM could better improve the recovery of hemopoietic system and alleviate the detrimental effects of radiation.
The results indicate that the combined application of HRW and AM may be a better method for radiation therapy.

New treatment modalities are developed with the aim of escalating tumor absorbed dose and simultaneously sparing the normal structures. The use of nanotechnology in cancer treatment offers some possibilities including destroying cancer tumors with minimal damage to healthy tissues. Zinc Oxide nanoparticles (ZnO NPs) are wide band gap semiconductors and seem to have a good effect on increasing the absorbed dose of target volume especially when doped with a high Z element. The aim of this study was to evaluate the effect of ZnO NPs doped with Gadolinium (Gd) on dose enhancement factor by 6MV photon beam irradiation.
Various concentrations of ZnO NPs doped with 5% Gd were incorporated into PRESAGE composition, the 3D chemical dosimeter. Then by using a UV-Vis spectrophotometer optical density changes and also dose enhancement factor (DEF) were determined.
The results of this study showed that by incorporating 500, 1000, 3000 and 4000 µg/ml ZnO NPs doped with Gd into PRESAGE structure the dose enhancement factor of about 1.57, 1.69, 1.78 and 1.82 in a 15 ×15 cm2 field size could be found, respectively.
The results of this study showed that ZnO NPs doped with Gd could be considered as new compound for increasing the absorbed dose.

It has recently been shown that the particle size of materials used for radiation shielding can affect the magnitude of radiation attenuation. Over the past years, application of nano-structured materials in radiation shielding has attracted attention world-wide. The purpose of this study was to investigate the shielding properties of the lead-free shields containing micro and nano-sized WO3 against low energy x-rays.
The radiation shields were constructed using nano and micro WO3 particles incorporated into an EPVC polymer matrix. The attenuation coefficients of the designed shields were evaluated for low energy x-rays (diagnostic radiology energy range).
The results indicate that nano-structured WO3/PVC shields have higher photon attenuation properties compared to those of the micro-sized samples.
Our experiment clearly shows that the smaller size of nano-structured WO3 particles can guarantee a better radiation shielding property. However, it is too early to draw any conclusion on the possible mechanisms of enhanced attenuation of nano-sized WO3 particles.

Radiology staff needs to justify the radiation exposures in order to protect themselves and others from radiation risks. The aims of this study were to examine the awareness level of radiation dose and protection amongst radiographers and to compare their performance between major Jordanian hospitals.
A cross-sectional survey was conducted in 4 major Jordanian hospitals. A total of 85 radiographers agreed to participate in the study. The questionnaire included demographic information, general radiation protection, radiation dose estimation and radiation induced cancer risk sections.
The average total score of radiographers in all hospitals was less than 50%. The lowest score was for radiation induced cancer questions section (34%). There was no significant difference in the level of awareness between radiographers from different hospitals except for the radiation dose awareness section (p= 0.001). Experience and training courses did not correlate significantly with the total score or with the score of individual sections.
The level of radiation dose and protection awareness amongst radiographers in the sampled Jordanian hospitals is inadequate. At this stage, establishing an annual assessment of the radiographer’s awareness through the Jordanian national radiation agency is highly encouraged.

The aim of the study was to estimate the radiation dose during emergency exposure to patients treated with iodine-131 during the isolation period.
The dose rate from a sample of 192 patients administrated by three different radioactivity of 131I (3.7, 5.55 and 7.4 GBq) was measured, at 1 meter after 1, 24 and 48 hours post dose administration, at three different levels from the patient body (thyroid glands, abdomen and knee). The average of decay curve of the measured radiation dose rate was plotted and their values were fitted. The medical emergency exposure was estimated in the form of an equation to take into account the duration and the position of the intervention.
The estimated radiation doses received during 10 minutes of intervention emergency at a distance of 20, 40 and 60 cm from patient after different times post dose administration were in the range of 72.2 to 1207.5, 18.1 to 301.9 and 8.0 to 134.2 µSv, respectively.
During the first ten hours following patient dose administration, the estimated emergency dose could be considered as high occupational dose value compared to the dose limit recommended by ICRP.

To evaluate the risk involved, there is need to know the quantum of personnel exposures in whole service. Dose reports from an Oncology Centre over 7 block periods, 5 years each from 1979 till 2013 are analyzed.
Personnel monitoring (PM) reports till 1990s with film badges and later thermoluminescent (TL) badges (CaSo4.Dy) were evaluated. 35 years total service was taken to represent total professional service of staff superannuating at age 60 years.
Mean personnel equivalent dose for 5 year block period is 3.30±0.43 mSv (n=7 blocks). Maximum dose in any block period was 30-60 mSv. Equivalent doses 22% were zero, 64.3% within 5 mSv. 2.1% were above 30 mSv in 5 year periods. Doses were decreasing order 11.8 mSv (radiopharmaceutical preparation), 4.3 mSv (nuclear medicine), 4.1 mSv (medical physics), 2.2 mSv(brachytherapy); 1.2 mSv (radiodiagnosis), 1.1 mSv (external beam radiotherapy) and 0.73 mSv (radiation sterilization plant).
The whole body personnel dose in are much lower than recommended annual dose equivalent limits of 100 mSv/ 5 years. The magnitude of recorded doses to staff show that the risk is negligible and the principle of ALARA is being practiced in the work areas.

Radiochromic film is used for radiation dose measurement, XR-RV3 is used in fluoroscopy and EBT2 film in radiation therapy. The aim was to determine if the dosimetric properties of these two films are comparable in megavolt photon beams.
Comparison measurements included: calibration curves, heterogeneous phantom dose profiles, and nasopharynx dose distribution measurement.
Both film types required 24 hours to stabilize. Their heterogeneous phantom dose profiles were similar, and their dose distributions for a nasopharynx treatment were within 3%/3mm.
Dose distributions between both films showed good correlation and XR-RV3 film can be used in radiotherapy for quality control checks.

An early diagnosis of breast cancer relates directly to an accurate treatment plan and strategy. Early detection of breast cancer before its development would be a significant reduction of morbidity and mortality rates. The aim of this preliminary study is to investigate the sensitivity of Wide Angle X-ray diffraction (WAXRD) method on women hair samples of healthy and breast cancer patients in comparison with other modalities such as synchrotron based XRD beam and mammography.
Hair samples were taken from occipital region of skull from healthy and breast cancer patients (43 women) were analyzed using X-ray diffraction and the results were analyzed and compared with mammography and pathology reports.
The results of analyzed samples showed the sensitivity for purposed WAXRD method was 86% in comparison with synchrotron based XRD beam (64%) and also with mammography (70%).
This non-invasive method is less harmful and is more sensitive than the two other methods and help the physicians for choosing accurate treatment plan.

This study set out to evaluate the utility of cerebrovascular virtual non-contrast (VNC) scans.
Conventional non-contrast (CNC) and dual-energy computed tomography angiography (DE-CTA) head scans were conducted on 100 subjects, of which 46 were normal, 15 had parenchymal hematomas of the brain, 13 had ischemic infarction, 22 had tumors, and 4 had calcified lesions. VNC images were extracted from the DE-CTA head scans by post-processing. The true (or conventional) and VNC images were compared in terms of the mean CT attenuation value and signal-to-noise ratio (SNR) of the cerebral parenchyma, the image quality, the lesion detection sensitivity, and the radiation exposure level.
The image qualities of the CNC and VNC scans were (4.95 ± 0.22) points and (3.94 ± 0.24) points (t = 31.18, P VNC and contrast-enhanced images could be obtained from DE-CTA head scans and could aid in the diagnosis of cerebral lesions. The radiation dose from the VNC scan was less than that from the CNC scan.