Showing 11 results for Dose
K Imandel , I Mobedi , A Mesdaghinia , F Vaezi ,
Volume 56, Issue 2 (4-1998)
Abstract
Wastewaters are one of the most important sources for transmission of pathogenic agents in environment, so they should be disinfected in a manner that their overall qualities become accordant with WHO-guidelines, if it is needed to reus water correctly. Unfortunately, the protozoa and parasitic worm's eggs can not be destroyed by chlorination alone. This experiment was carried out in order to determine the efficiency of the UV-Lamps in inactivation of the Ascaris Lumbericoides-ova which is the most resultant organism among the other nematode eggs. The minimum inhibitory dose of UVR (UVC plus UVB irradiances) for Ascaris-ova complete destruction ascertained to be 420 miliwatts-seconds per square centimeter.
Fard Esfahani A, Dabbagh Kakhki Vr, Eftekhari M, Zarpak B, Saghari M, Fallahi Sijani B,
Volume 61, Issue 4 (7-2003)
Abstract
Radioiodine therapy is the safest, simplest, least expensive and most effective method for treatment of Graves' disease. Due to difficulties in previous methods for dose determination, fixed dose method of 1-131 is now considered the best practical method for 1-131 therapy in Graves' disease, but there is no consensus on the dose. We compared two routinely recommended fixed doses of 5 and 10 mCi for this purpose.
Materials and Methods In this clinical trial, 59 patients with Graves' disease referred for radioiodine therapy were randomized into two groups, one group was treated with 5 mCi of 1-131 and the other with 10 mCi. All patients were followed for two years, with 6-month intervals.
Results: Totally, among 59 patients treated with 1-131, 20 (33.9%) patients became euthyroid and 19(32.2%) became hypothyroid, while failed therapy (no response or relapse) was noticed in 20 patients (33.9%). In the group treated by 5 mCi (33 patients), 10(30.3%) were euthyroid, 6(18.2%) were hypothyroid (overall cure of ^8.5%), while 17(51.5%) remained hyperthyroid by the end of the follow-up period. From the 26 patients treated with 10 mCi, the euthyroid and hypothyroid states were observed in 10(38.5%) and 13(50%)patients, respectively (overall cure rate of 88.5%), and hyperthyroid state in 3(11.5%). No relationship was noted between the outcome and age, sex, size of the thyroid gland and thyroid uptake, but the relationship between the disease outcome and the amount of administered radioiodine was significant (P<0.003). Although the incidence rate of early hypothyroidism (by the end of 2 years) in the group treated with 5 mCi is less than those treated with 10 mCi, the incidence of failed therapy is higher in the former group. In addition, it is known that long-term hypothyroidism prevalence is not significantly different by using different doses of I-131. On the other hand, if the initial dose is so little to cure, cost and time for perfect treatment, number of office visits and morbidity due to untreated hyperthyroidism are markedly increased.
Conclusion: Regarding lower rate of failed therapy with 10 mCi, and as there is no significant difference in late hypothyroidism between low doses and high doses of I-131, we concluded that 10 mci is the optimal fixed dose for treatment of Graves' disease.
A Rahimi, E. Mohammad Razzaghi ,
Volume 64, Issue 4 (7-2006)
Abstract
Background: Injection drug use (IDU) in Iran is not rare and is one of the main factors in opioid overdose. The objective of this study was the qualitative assessment of overdose, related factors, and available interventions.
Methods: A qualitative method was employed. Six districts of Tehran with a population of 400,000 inhabitants were selected. The districts were different in socioeconomic characteristics, urban structures and prevalence of IDU and crime. A total of 81 key informants from different sectors and 154 injection drug users (IDUs) were selected by purposeful, opportunistic and snowball sampling, and interviewed individually or in groups. Ethnographic observations were done for studying the life situation of IDUs.
Results: In one district no cases of IDU were found. In other districts, overdose in IDUs was reported to be common. Heroin injection alone or in combination with other drugs was the main reported cause of overdose. Reportedly, wrong estimation of drug purity was the most important reason. Even in the districts with highest rate of IDU and overdose, most clinics and hospitals did not have enough facilities necessary for management of acute opioid overdose.
Conclusion: According to the high prevalence of overdose, provision of preventive education of drug users and their relatives and availability and accessibility of emergency services is highly recommended.
Mowlavi A A,
Volume 65, Issue 3 (6-2007)
Abstract
Background: Accurate computation of the radiation dose to the breast is essential to mammography. Various the thicknesses of breast, the composition of the breast tissue and other variables affect the optimal breast dose. Furthermore, the glandular fraction, which refers to the composition of the breasts, as partitioned between radiation-sensitive glandular tissue and the adipose tissue, also has an effect on this calculation. Fatty or fibrous breasts would have a lower value for the glandular fraction than dense breasts. Breast tissue composed of half glandular and half adipose tissue would have a glandular fraction in between that of fatty and dense breasts. Therefore, the use of a computational code for average glandular dose calculation in mammography is a more effective means of estimating the dose of radiation, and is accurate and fast.
Methods: In the present work, the Sobol-Wu beam quality parameters are used to write a FORTRAN code for glandular dose calculation in molybdenum anode-molybdenum filter (Mo-Mo), molybdenum anode-rhodium filter (Mo-Rh) and rhodium anode-rhodium filter (Rh-Rh) target-filter combinations in mammograms. The input parameters of code are: tube voltage in kV, half-value layer (HVL) of the incident x-ray spectrum in mm, breast thickness in cm (d), and glandular tissue fraction (g).
Results: The average glandular dose (AGD) variation against the voltage of the mammogram X-ray tube for d = 4 cm, HVL = 0.34 mm Al and g=0.5 for the three filter-target combinations, as well as its variation against the glandular fraction of breast tissue for kV=25, HVL=0.34, and d=4 cm has been calculated. The results related to the average glandular absorbed dose variation against HVL for kV = 28, d=4 cm and g= 0.6 are also presented. The results of this code are in good agreement with those previously reported in the literature.
Conclusion: The code developed in this study calculates the glandular dose quickly, and it is complete and accurate. Furthermore, it is user friendly and useful for dose optimizing in mammography imaging.
Amouzegar Hashemi F, Zahedi F, Farhan F, Kalaghchi B, Mehrdad N, Haddad P,
Volume 66, Issue 12 (3-2009)
Abstract
Background: Treatment of cervical carcinoma is routinely performed with Low Dose Rate (LDR) brachytherapy, but Brachytherapy in our department is done with Medium Dose Rate (MDR) due to the technical characteristics of the machine available here. Thus we decided to evaluate the results of this treatment in our department in a prospective study.
Methods: Between March 2006 and July 2008, 140 patients with histologic diagnosis of cervical carcinoma referred to Tehran Cancer Institute were treated with external beam radiotherapy (44-64 Gy to whole pelvis) and MDR brachytherapy (8-30 Gy to Point A) with a dose rate of 2.2±0.3 Gy/h.
Results: 121 patients were followed up for a median time of 18 months (range: 9-39 m). There were 11%(6/54) local recurrence for surgery and adjuvant radiotherapy group 25%(16/65) for radical radiotherapy group, and 19%(23/121) for all patients. Rectal and bladder complications incidence for all patients were 10%(12/121) and 13%(16/121) respectively. High grade complication was shown only in one patient in radical radiotherapy group. In this study 3-years disease free survival and overall survival were 73% and 92% respectively, and disease stage (p=0.007) and overall treatment time (p=0.05) were the significant factors affecting disease free survival.
Conclusions: Results of this series suggest that the use of external beam radiotherapy and MDR brachytherapy with about 20% dose reduction in comparison with LDR can be an acceptable technique with regard to local control and complications.
Khalilpour M, Norouzzadeh Sh, Dadras M,
Volume 67, Issue 4 (7-2009)
Abstract
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Background: CT scan was first introduced into clinical
practice in 1972, and since then has
grown into one of the predominant diagnostic procedures. In
1998, the UK National
Radiological Protection
Board reported that 20%
of the national collective dose from medical X-ray
examinations derived from CT-scans, although it
represented only 2% of all X-
ray examinations the aim of this study was to determine the X-ray
dosage received by patients in brain CT
scan.
Methods: In this work, we have estimated patient dose arising from CT
examination of brain in five hospitals in Tehran.
Organ and effective doses were estimated for 150
patients who underwent CT examination of
brain. "ImPACT"
version 0.99v was used to estimate
organ and effective dose. Brain examinations
were performed with fixed Kvp, mAs
and T (slice thickness) for each scanner.
Results: Patients, who were scanned by CT
of emam Khomeini center (Toshiba
Xvision /EX
Scanner), received maximum organ dose (brain) and minimum organ dose was
delivered to patients who were scanned by CT
of amir alam center (Toshiba Xvision
/EX Scanner). Maximum effective dose was 1.7
mSv acquired in this study for emam Khomeini
haspital, smaller than the corresponding value obtained by National Radiation
Protection British
(NRPB).
Conclusions: In
two research centers with a system, the obtained results of measurement of
effective dose and organ dose show utilization method of system and its measure
of Kvp & mAs
is very important factor in comparison with type of system. Because
there are both minimum dose and maximum dose in two different centers.
Bahari A, Izadi Sh, Adibi P, Sanee-Moghadam E, Khosravi H, Shahraki T,
Volume 69, Issue 4 (7-2011)
Abstract
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Background: With respect to the importance of hepatitis B
vaccination of high-risk groups such as prisoners, this study was performed to assess
the comparability of a short-course double-dose vaccination schedule with the
standard 3-dose schedule.
Methods : Within a randomized clinical trial, a short-course vaccination (at months 0
and 1) with 20
microgram (double-dose) doses of the vaccine was compared to the standard
method of hepatitis B vaccination (at
months 0, 1 and 6,
with 10-microgram doses) in 100
prisoners in Zahedan city in Iran in 2009.
We made sure the sera from all the individuals were negative for markers of
previous hepatitis B infection. Subsequently
serum from all the participants was tested for anti-HBs
antibody 1, 2 and 7
months after the first dose of vaccination.
Results : Seroconversion rates (HBsAb>10
mIU/ml) 1, 2
and 7 months after the first dose of vaccination
were similar in the routine (11%, 79% and 94%,
respectively) relative to the double-dose group (26%, 95% and
93 %, respectively). The mean values of anti-HBs
antibody titers were similar in the 1st and 2nd
months for the two groups but it was significantly higher (P=0.002)
in the routine dose (514 mIU/ml)
versus the double-dose group (130 mIU/mL),
in the 7th month.
Conclusion: Demonstrating
comparable results with the standard 3-dose
schedule, it seems that short-term double-dose vaccination for hepatitis B is
a safe and acceptable method for use in high-risk groups such as prisoners.
Peiman Haddad , Zhaleh Karimimoghaddam , Farshid Farhan , Mahbod Esfahani , Mahdieh Afkhami , Farnaz Amouzegar-Hashemi,
Volume 71, Issue 11 (2-2014)
Abstract
Background: Colorectal carcinoma is a common malignancy, in treatment of which pelvic radiotherapy plays an important role. But this may lead to azospermia. We designed a study to determine the delivered dose to the testis with thermoluminescence dosimetry (TLD) and compare it to the dose calculated by the Three-dimensional planning software.
Methods: We measured the testicular doses by TLD the TLDs were fixed to the scrotum in six points anteriorly and posteriorly in two random fractions of the radiation course. All patients received a 50-50.4 Gy radiation dose to the pelvis in a prone position with standard fractionation and 3-dimensional planning, through three or four fields. The average dose of the TLD measurements was compared to the average of 6 relevant point doses calculated by the planning software.
Results: In 33 patients with a mean age of 56 years, the mean testis dose of radiation measured by TLD was 3.77 Gy, equal to 7.5% of the total prescribed dose. The mean of point doses calculated by the 3-dimensional planning software was 4.11 Gy, equal to 8.1% of the total prescribed dose. A significant relationship was seen between the position of the inferior edge of the fields and the mean testis dose (P= 0.04). Also body mass index (BMI) was inversely related with the testicular dose (P= 0.049).
Conclusion: In this study, the mean testis dose of radiation was 3.77 Gy, similar to the dose calculated by the planning software (4.11 Gy). This dose could be significantly harmful for spermatogenesis, though low doses of scattered radiation to the testis in fractionated radiotherapy might be followed with better recovery. Based on above findings, careful attention to testicular dose in radiotherapy of rectal cancer for the males desiring continued fertility seems to be required.
Shadi Khazaei, Shahrbanoo Keyhanian , Mahila Monajati , Shahram Ala, Ebrahim Salehifar ,
Volume 75, Issue 9 (12-2017)
Abstract
Background: Methotrexate (MTX) is commonly used in the hematology-oncology units and is frequently associated with adverse effects. High-dose methotrexate (HDMTX) is indicated in the treatment of acute lymphoblastic leukemia (ALL), osteosarcoma, systemic non-Hodgkin lymphoma and primary central nervous system (CNS) lymphoma. The side effect profile of MTX varies markedly according to dose. The aim of this study was to evaluate the uses and adverse effects of HDMTX in a cancer center in north of Iran.
Methods: This cross-sectional descriptive study carried out in Emam Sajjad Hospital, Ramsar, Iran from June 2016 to July 2017. Doses more than 500 mg/m2 of MTX was considered as a high-dose. Hydration status, evaluation of the renal and hepatic function, blood tests, urine pH, doses and frequencies of leucovorin administration, measurement of serum levels of MTX and side effects were evaluated. Recommendations of UpToDate 2017 were considered as standards of administration of HDMTX.
Results: Forty-four courses of HDMTX were evaluated in this study. HDMTX were prescribed for lymphoma (30 cases), ALL (8 cases) and osteosarcoma (6 cases). In all patients, hydration was done with 1340.9±894 normal saline plus 25 ml sodium bicarbonate 8.4%, one to two hours before HDMTX. The solution used for dilution of MTX was 5% dextrose (1022.7±105.5 ml). Urine pH was not measured in any patient. The frequency of leucovorin administration was 5.64±3.03 times with doses of 17.6±1.7 mg/m2 every 6 hours. Serum levels of MTX were not measured in any patient. Blood urea nitrogen and creatinine measurement was carried out before administration of HDMTX in all patients. The most common adverse effects were nausea (64.4%), anxiety (44%) and headache (43.2%).
Conclusion: The appropriate aspects of HDMTX usage were good hydration, urine alkalinization with bicarbonate and administration of leucovorin in patients receiving HDMTX, whereas monitoring of serum levels of MTX and administration of bicarbonate based on urinary pH were not done in any of the patients.
Elham Hoseinnezhad Zarghani, Ghazale Geraily, Mahbod Esfahani, Mostafa Farzin,
Volume 78, Issue 7 (10-2020)
Abstract
Background: Total body irradiation (TBI) is a technique that is commonly used as a part of the patient conditioning regimen before the bone marrow transplant (BMT). The purpose of this study is to introduce and implement a reasonable TBI technique on the human-like phantom in Imam Khomeini Hospital in Tehran.
Methods: The present experimental study was conducted from October 2016 to November 2017 to implement the TBI technique at the Cancer Institute of Imam Khomeini Hospital in Tehran. For this purpose, percentage depth dose, and dose rate were measured in TBI condition (i.e. SSD=310 cm, field size=40×40 cm2, gantry angle=90°, and collimator angle 45°) in homogeneous phantom. Gafchromic EBT3 films were used to measure the absorbed dose in different areas of the human like phantom at the levels of head, neck, thyroid, lung, umbilicus, pelvic, thigh, knee and leg. Phantom irradiation was performed in parallel opposed anterior-posterior geometry using an 18MV photon beam produced by Varian 2100C/D. Cerrobend blocks were used for lung protection. After analyzing the exposed films with Image J software, the dose uniformity was calculated.
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Results: Dose distribution uniformity was acquired in the order of -1.01% to +11.82% relative to the prescribed dose at the umbilicus. The difference between the calculated and measured dose at the umbilicus level was -2.73%. The radiation absorbed dose to the lung with blocks was 127.53cGy in one fraction which resulted in 756.18cGy in six fractions.
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Conclusion: The implemented technique, obtained the acceptable ±10% dose uniformity in most of the body regions. The dosing accuracy was within the acceptable range. The lungs¢ dose was reduced to the desired level using lung shields. This technique is a simple and cost-effective method that does not require complicated dosimetric techniques. Regarding the obtained results, the proposed technique has the necessary conditions for implementation in Imam Khomeini hospital in Tehran.
Arezoo Kazemzadeh, Iraj Abedi, Alireza Amouheidari, Atefeh Shirvany,
Volume 78, Issue 9 (12-2020)
Abstract
Background: To date, different kinds of treatment methods have been proposed for radiotherapy of cancer patients. Choosing the kind of treatment method affects the quality of the patient's treatment. This study aims to investigate the effect of the number of radiation treatment sessions on the dose received by the patient and the distribution of tumor dose and dose received by organs at risk in breast cancer radiation therapy. These results help us to select the appropriate treatment schedules for the treatment of left breast patients.
Methods: This prospective cross-sectional study was performed on the treatment plans of 35 patients with left breast cancer who referred to Isfahan Milad Hospital between July 2019 and April 2020. They were candidates for left breast radiation therapy. Also, these patients had no history of surgery or chemotherapy, and no supraclavicular or axillary lymph nodes were involved. Patients were treated with a conventional fraction regimen (CF) or hypofractionated (HF) treatment schedule. Different dosimetry parameters for the target and organ at risks such as conformity index, homogeneity index and mean dose were obtained from the dose-volume histogram plot. Finally, the results of both plans were compared with each other.
Results: The data obtained from this study indicate a decrease in the average dose of all organs in the hypo fractionated regimens compared to conventional plans. The differences between two plans were statistically significant for tumor, lung, and skin (P=0.0). Moreover, the maximum dose for the skin was also reduced when hypofractionated regimens were used. However, the values of the homogeneity index and conformity index of tumor in the two methods did not show a significant difference (P were 0.99 and 0.86, respectively).
Conclusion: In general, the results of the current study indicate that the hypofractionated regimen leads to a reduction in dosimetric factors compared to conventional fraction plans. It seems that this method can be used as an alternative treatment plan for breast cancer radiation therapy due to the reduced duration of the treatment period. |
