Elham Karimi

Dosimetric comparison of 90Y, 32P, and 186Re radiocolloids in craniopharyngioma treatments.

PURPOSE In the radionuclide treatment of some forms of brain tumors such as craniopharyngiomas, the selection of the appropriate radionuclide for therapy is a key element in treatment planning. The aim was to study the influence by considering the beta-emitter radionuclide dose rate in an intracranial cyst. METHODS Dosimetry was performed using the MCNP4C radiation transport code. Analytical dosimetry was additionally performed using the Loevinger and the Berger formulas in the MATLAB software. Each result was compared under identical conditions. The advantages and disadvantages of using Y90 versus P32 and Re186 were investigated. RESULTS The dose rate at the inner surface of the cyst wall was estimated to be400mGy∕h for a 1MBq∕ml concentration of Y90. Under identical conditions of treatment, the corresponding dose rates were 300mGy∕h for P32 and 160mGy∕h for Re186. For a well-defined cyst radius and identical wall thickness, higher dose rates resulted for Y90. CONCLUSIONS To achieve the same radiological burden, the required amount of physical activity of injectable solution is lower forP32. This is found to be a consequence of both the radionuclide physical half-life and the pattern of energy deposition from the emitted radiation. According to the half-life and dose-rate results, Y90 would be a good substitute for P32.

Monte Carlo and analytical calculations of dose distributions in craniopharyngioma cysts treated with radiocolloids containing 32P or 186Re.

In radiation treatments of some types of brain tumors, such as craniopharyngiomas, selection of an appropriate radionuclide is critical. The aim of this work was to calculate distributions of dose rates from (32)P and (186)Re in radiocolloids injected into craniopharyngioma cysts. The calculations were performed with the MCNP4C radiation transport code. Analytical calculations based on the Loevinger formula were also performed for (32)P with the MATLAB software. The results of the two techniques for identical models were compared. The effects of the cyst wall type and of the density of the cyst inner fluid were investigated. The (32)P activities required for providing 200, 250, and 300 Gy to cysts of different sizes were calculated.

Analytical comparison of traffic noise indices—A case study in District 14 of Tehran City

Noise pollution is a growing concern of majority of people around the world. Accordingly, the present study was carried out to analyze, for the first time, traffic noise indices and to introduce an optimal noise index for road traffic noise. For this purpose, the District 14 of Tehran Metropolitan City was selected as a case study wherein a total number of 91 stations were selected so as to cover noise susceptible areas. The measurements were performed at three occasions of morning, noon, and evening. In order to estimate the traffic noise index, noise pollution level, and noise impact index, the L10, L50, and L90, were recorded at each station with 40 replicates. According to the obtained results, among different land uses in the study area, the maximum and minimum traffic noise index values of 113.7 dBA and 50.1 dBA were reported from educational land use. The highest noise pollution level of 96.8 dBA was measured at the educational land use while the lowest noise pollution level of 65 dBA was recorded at the medical land use. The noise impact index value was estimated at 1.5 for the entire region indicating noise level is much higher than the acceptable threshold for residents. Overall, noise pollution level would be a better index when the objective is to measure the overall noise pollution condition in the study area, whereas it gives much more weight to the difference between the ambient and peak noise levels. However, in situations where traffic-induced noise measurement is required, the traffic noise index seems more appropriate. Further, the noise impact index would be more useful to quantify the effect of noise pollution on exposed people.

SPATIAL TRAFFIC NOISE POLLUTION ASSESSMENT - A CASE STUDY

OBJECTIVES Spatial assessment of traffic noise pollution intensity will provide urban planners with approximate estimation of citizens exposure to impermissible sound levels. They could identify critical noise pollution areas wherein noise barriers should be embedded. The present study aims at using the Geographic Information System (GIS) to assess spatial changes in traffic noise pollution in Tehran, the capital of Iran, and the largest city in the Middle East. MATERIAL AND METHODS For this purpose, while measuring equivalent sound levels at different time periods of a day and different days of a week in District 14 of Tehran, wherein there are highways and busy streets, the geographic coordination of the measurement points was recorded at the stations. The obtained results indicated that the equivalent sound level did not show a statistically significant difference between weekdays, and morning, afternoon and evening hours as well as time intervals of 10 min, 15 min and 30 min. Then, 91 stations were selected in the target area and equivalent sound level was measured for each station on 3 occasions of the morning (7:00-9:00 a.m.), afternoon (12.00-3:00 p.m.) and evening (5:00-8:00 p.m.) on Saturdays to Wednesdays. RESULTS As the results suggest, the maximum equivalent sound level (Leq) was reported from Basij Highway, which is a very important connecting thoroughfare in the district, and was equal to 84.2 dB(A), while the minimum equivalent sound level (Leq), measured in the Fajr Hospital, was equal to 59.9 dB(A). CONCLUSIONS The average equivalent sound level was higher than the national standard limit at all stations. The use of sound walls in Highways Basij and Mahallati as well as widening the Streets 17th Shahrivar, Pirouzi and Khavaran, benchmarked on a map, were recommended as the most effective mitigation measures. Additionally, the research findings confirm the outstanding applicability of the Geographic Information System in handling noise pollution data towards depicting noise pollution intensity caused by traffic.

Outdoor Noise Pollution Mapping Case Study: A District of Tehran

The main objective of this study was to investigate the noise levels at different land uses of District 14 in Tehran. For this purpose, a total number of 91 sampling stations were selected. Afterwards, the equivalent sound pressure level in each station was measured at three occasions of morning (7–9 am), noon (12–3 pm), and evening (5–8 pm). Based on the conformability requirement of each land uses, noise levels was divided in three zones wherein the land uses are exposed to different noise levels was estimated. The obtained results indicated that 8.79% of 78 land uses (residential, recreational and medical) in the Zone 1 were exposed to acceptable range of sound pressure level while the rest suffers from unacceptable noise levels. Among 10 land uses of Zone 2 (commercial–residential), 2.19% were within the acceptable range and 8.78% were in unacceptable range. None of the three land uses in Zone 3 were within the acceptable range. Accordingly, the Zone 3 was recognized to be in a critical condition. In other words, about 88.99% of the total and uses in the Zone 3 is exposed to unaccepted able noise level. Comparing with the standard equivalent sound pressure level of 55 dB(A) presented, the residential land use with the equivalent sound pressure level of 19.27 dB(A) accounted for the highest standard deviation. This is due to proximity of most of the residential areas to the crowded highways and streets.

Dosimetric comparison of Y90, P32, and Re186 radiocolloids in craniopharyngioma treatments

PURPOSE In the radionuclide treatment of some forms of brain tumors such as craniopharyngiomas, the selection of the appropriate radionuclide for therapy is a key element in treatment planning. The aim was to study the influence by considering the beta-emitter radionuclide dose rate in an intracranial cyst. METHODS Dosimetry was performed using the MCNP4C radiation transport code. Analytical dosimetry was additionally performed using the Loevinger and the Berger formulas in the MATLAB software. Each result was compared under identical conditions. The advantages and disadvantages of using Y90 versus P32 and Re186 were investigated. RESULTS The dose rate at the inner surface of the cyst wall was estimated to be400mGy∕h for a 1MBq∕ml concentration of Y90. Under identical conditions of treatment, the corresponding dose rates were 300mGy∕h for P32 and 160mGy∕h for Re186. For a well-defined cyst radius and identical wall thickness, higher dose rates resulted for Y90. CONCLUSIONS To achieve the same radiological burden, the required amount of physical activity of injectable solution is lower forP32. This is found to be a consequence of both the radionuclide physical half-life and the pattern of energy deposition from the emitted radiation. According to the half-life and dose-rate results, Y90 would be a good substitute for P32.

Investigation of the Traffic Noise Attenuation Provided by Roadside Green Belts

Greenbelts are remarkably effective tools for minimizing traffic induced noise pollution. This study revealed the potential role of greenbelts along the roadside for the noise attenuation using var...

Dosimetry of 32P Radiocolloid for Radiotherapy of Brain Cyst

In the radionuclide treatment of some forms of brain tumors such as craniopharyngiomas, the selection of the appropriate radionuclide for therapy is a key element in treatment planning. The aim of present study was to study the influence of 32P in the radionuclide therapy of craniopharyngioma cysts by considering to its dose rate to sites of the diseased tissues. Dosimetry calculations were performed by utilizing the MCNP4C radiation transport code. Analytical dosimetry was additionally performed using the Loevinger formula in MATLAB software for 32P. Each result was compared under identical conditions. The needed activity for injection according to the cyst volume was also obtained in the case of 32P. At the range of 200–300 Gy dose, changes of activity was studied too. Increasing desired dose for therapy results in growth of essential activity for treatment.

Dosimetric comparison of {sup 90}Y, {sup 32}P, and {sup 186}Re radiocolloids in craniopharyngioma treatments

PURPOSE In the radionuclide treatment of some forms of brain tumors such as craniopharyngiomas, the selection of the appropriate radionuclide for therapy is a key element in treatment planning. The aim was to study the influence by considering the beta-emitter radionuclide dose rate in an intracranial cyst. METHODS Dosimetry was performed using the MCNP4C radiation transport code. Analytical dosimetry was additionally performed using the Loevinger and the Berger formulas in the MATLAB software. Each result was compared under identical conditions. The advantages and disadvantages of using Y90 versus P32 and Re186 were investigated. RESULTS The dose rate at the inner surface of the cyst wall was estimated to be400mGy∕h for a 1MBq∕ml concentration of Y90. Under identical conditions of treatment, the corresponding dose rates were 300mGy∕h for P32 and 160mGy∕h for Re186. For a well-defined cyst radius and identical wall thickness, higher dose rates resulted for Y90. CONCLUSIONS To achieve the same radiological burden, the required amount of physical activity of injectable solution is lower forP32. This is found to be a consequence of both the radionuclide physical half-life and the pattern of energy deposition from the emitted radiation. According to the half-life and dose-rate results, Y90 would be a good substitute for P32.

Dosimetric comparison of Y90, P32, and Re186 radiocolloids in craniopharyngioma treatments: Dosimetric comparison of Y90, P32, and Re186

PURPOSE In the radionuclide treatment of some forms of brain tumors such as craniopharyngiomas, the selection of the appropriate radionuclide for therapy is a key element in treatment planning. The aim was to study the influence by considering the beta-emitter radionuclide dose rate in an intracranial cyst. METHODS Dosimetry was performed using the MCNP4C radiation transport code. Analytical dosimetry was additionally performed using the Loevinger and the Berger formulas in the MATLAB software. Each result was compared under identical conditions. The advantages and disadvantages of using Y90 versus P32 and Re186 were investigated. RESULTS The dose rate at the inner surface of the cyst wall was estimated to be400mGy∕h for a 1MBq∕ml concentration of Y90. Under identical conditions of treatment, the corresponding dose rates were 300mGy∕h for P32 and 160mGy∕h for Re186. For a well-defined cyst radius and identical wall thickness, higher dose rates resulted for Y90. CONCLUSIONS To achieve the same radiological burden, the required amount of physical activity of injectable solution is lower forP32. This is found to be a consequence of both the radionuclide physical half-life and the pattern of energy deposition from the emitted radiation. According to the half-life and dose-rate results, Y90 would be a good substitute for P32.