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Background: Immunoradiometric assay is one of the most common and precise methods for determination of prostate specific antigen (PSA) in clinical laboratories. Usual use of human serum in routine assays has many disadvantages such as easy contamination and precipitation, instability and unavailability. Thus in order to avoid these problems the artificial matrix was used which acts similar to human serum. Materials and Methods: In order to design immunoradiometric assay for prostate specific antigen, series of standards in different concentrations were needed for special artificial matrix preparation. The influence of artificial matrix in standards was studied to determine prostate specific antigen in comparison with human serum. Some different factors, such as the amount of non-specific bonding (NSB), precision, and accuracy, conditions of storage and stability of these standards prepared by artificial matrix were investigated. Results: The most appropriate artificial matrix (Tris-glycine (25.0 mmol/L) + NaCl (75.0 mmol/L) + Tris (12.5 mmol/L) +Triton X- 100 (0.5 ml/L) + HSA (1.2 g/L) + Urea (0.5 mol/L)) for preparing the standards was selected in comparison with human serum (HSA) and a commercial kit standards. HSA and Urea concentration have more critical influences on the properties of the standards. The amount of NSB of the selected matrix was the lowest one, so the selected matrix was the most suitable for preparing the standards. The results show the optimum condition of storage duration of our standards for one year was in refrigerator (2-8°C). It was observed that preparation of standards with selected matrix had acceptable accuracy and precision. Conclusion: According to the results, standards which were prepared with this matrix had suitable and appropriate properties and it could be utilized to prepare PSA standards in immunoradiometric assay. Iran. J. Radiat. Res., 2008 6 (1): 51-58

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Background: Owing to its favourable decay characteristics 177Lu [T1/2= 6.71 d, Eβ(max)= 497 keV] is an attractive radionuclide for various therapeutic applications. Ethylene diamine tatramethylene phosphonate (EDTMP) is one of the most widely used ligands which form stable complexes with various radionuclides and all the complexes. Materials and Methods: Enriched 176Lu2O3 was dissolved in 0.1 N HCl and evaporated several times and 176LuCl3 target was irradiated at 2.6×1013 n.Cm- 2.S-1 thermal neutron flux for 14 days.177LuCl3 was dissolved in 1N HCl. EDTMP was dissolved in double distilled water at pH=7.5-8.5 and freeze-dried kits was radiolabeled with 177LuCl3. Distribution studies were done in healthy mice. Results: The yield of 177Lu was (~220 TBq/g 6000 Ci/g), the radionuclidic purity was ~99%.The radiolabeling yield of EDTMP kits at 37°C after 30 min and 4 hours was 98±0.5% and after 72 hours was 90±2.1%, the in vitro stability in human serum at 37°C up to 72 hours post radiolabeling was 85±1.8%.The biodistribution studies of 177Lu-EDTMP and 177LuCl3 in normal mice showed skeleton uptake and low soft-tissue concentration. Conclusion: In this study, we produce ~220 TBq/g (6000 Ci/g) of 177Lu by neutron activation of 176Lu in the Tehran Research Reactor. Our results showed 177Lu-EDTMP as a bone-seeking radiopharmaceutical. Due to its suitable nuclear characteristics 177Lu appears to be worthwhile for palliative therapy of bone metastasis. Iran. J. Radiat. Res., 2010 7 (4): 229-234

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Background: In recent years, neoadjuvant chemoradiation and subsequent surgical resection with total mesorectal excision has been shown to increase local control with decreased toxicity. Neoadjuvant chemoradiotherapy is the standard treatment for locally advanced rectal cancer. In this study we evaluated the efficacy a cox-2 inhibitor on pathologic response, sphincter preservation and acute toxicity during neoadjuvant chemoradiation. Materials and Methods: Thirty-six patients with Adenocarcinoma of rectum (up to 15 cm of anal verge) was enrolled in this phase 2 study. Patients were undergone endorectal ultrasound, abdomino-pelvic and chest CT scan for staging. Then received neoadjuvant concurrent chemo radiation (capecitabine 825 mg/m2 bid in combination with celecoxib 100 mg qid and Radiotherapy “50-50.4Gy/25-28fraction”).Surgery was done 6-8 weeks after Chemoradiation. Acute complications were scored by common toxicity criteria 3.0 and tumor response was graded by tumor regression grade. Results: Of 36 patients, total mesorectal excision was done in 30 patients. Tumor regression grade was reported as:8 patients(26.7%) had grade 0 or complete response, 10 patients (33.3%) had grade 1 or moderate response,9 patients(30%) had grade 2 or minimal response and 3 patients (10%) had grade 3 or poor response. Tumor down staging was 43.3% and Node down staging was 30.8%.No patient had skin reaction or cardio-vascular toxicity. Conclusion: Results indicate celecoxib in combination with neoadjuvant chemoradiation is safe and associated with low toxicity. This combination can promote pathologic complete response, tumor regression grade and T and N down staging in rectal adenocarcinoma.

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Background: This research was conducted to evaluate the potential benefits of zinc sulphate in the prevention of radiation induced mucositis in patients who are being treated for head and neck cancers. Materials and Methods: Forty patients with proven cancers of head and neck were randomly divided into 2 equal groups that either received zinc sulphate or placebo (control group). Patients who received curative radiotherapy or chemoradiotherapy were instructed to take zinc sulphate capsules (30 mg) daily at 8 hours interval. They were to begin 10 days before the start of treatment and continued until 2 weeks after completing the schedule. Mucositis was evaluated weekly according to the Oral Mucositis Assessment Scale (OMAS). Results: In both groups (zinc and control) mucositis was evident during the first week but its prevalence was 40% and 70.5% in the zinc and placebo groups respectively at the end of this period. This difference was significant (p<0.0001). The mean severity of oropharyngeal mucositis increased after commencement of radiotherapy and reached to maximum intensity in the 4^th week. Control group showed higher severity (p<0.0001). In comparison with the placebo group, the mucositis score of OMAS in the zinc group was lower until at 2 weeks after end of the treatment (p=0.0001). Conclusion: The present study shows that Zinc sulfate is effective in reducing the severity of radiation induced oropharyngeal mucositis. In addition, it delays the development of mucositis and may be used at a lower dose (30 mg 3 times daily) with the same benefit but fewer side effects.

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Background: The purpose of this project was to derive the brachytherapy dosimetric functions described by American Association of Physicists in Medicine (AAPM) TG-43 U1 based on high dose rate ¹⁹²I sources. Materials and Methods: The method utilized included both simulation of the designed Polymethyl methacrylate (PMMA) phantom using the Monte Carlo of MCNP4C and benchmarking of the simulation with thermoluminescent (TL) dosimeters. Results: The obtained results for the radial dose function and anisotropy function showed nominal errors of less than 3% between TL measurements and the MCNP4C results. Conclusion: It may be concluded that due to small observed errors and the large uncertainty associated with the high dose gradients near the source point the simulation results can be used for dose estimation.

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Background: Rhabdomyosarcoma is a rare malignant soft tissue sarcoma and the most common sarcoma of childhood. The purpose of this study was to investigate the distribution of age and sex of patients, pathological subtypes and to determine the role of staging and classification of RMS on treatment outcome. Materials and Methods: This retrospective study included patients who diagnosed with RMS in Cancer Institute between 2006 and 2013. We used the Kaplan Meier and life table methods to estimate survival rate. STATA statistical software ver. 11.2 was used for statistical analyses. Results: Thirty patients with a mean age of 15.1 years (±SD =18.1) were evaluated.66.6 Percent were males. Median follow-up for survivors was 57.3 months (±SD=32.4). Survival rates of patients were as follows: 6 months (94%), 1 year (87%), 3 years (69%), and 5 years (50%). The pathology review classified of tumors as botryoid (6.7%), spindle cell (6.7%), embryonal (40%), alveolar (33.3%) and undifferentiated (13.3%). 3 years survival for patients with international classification III (alveolar and undifferentiated) was 70%, International classification II (embryonal) was 67%. Due to small sample size, we can’t report 3 years survival for international classification I (botryoid and spindle cell). Conclusion: Our results support early age of onset (>50% of RMS cases are diagnosed before age 10 years). Age of diagnosis often gives key facts about clinical behavior and has a noticeable effect on 5 year survival it is a prognostic factor in RMS. Disease extent as well as age and histology affect survival.

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Background: Ewing Sarcoma Family of Tumors (ESFTs) is the second most common primary tumors of bone in childhood. The decision regarding the optimal modality for achieving local tumor control remains uncertain. The aim of this study was to report the clinical features and outcome as well as reviewing risk factors in patients. Materials and Methods: This retrospective study included 75 ESFTs patients who were treated at cancer institute between 2004 and 2009. Files of all patients with ESFTs were reviewed retrospectively and we called them for follow up. Specific data were collected with regard to the age at diagnosis, gender, tumor site and size, clinical stage, surgical procedure, plan of radiotherapy and treatment outcome (5-year and median survival). Results: The mean age at diagnosis was 21 that ranged from 1 to 52 years (SD = 9.6). The mean tumor size at diagnosis was 4.8±4.48 cm. The percent of biopsy only, partial and complete resection was 54.7% (41 patients), 6.7% (5 patients) and 37.3% (28 patients) respectively. Radiotherapy was done as definitive treatment or postoperatively (adjuvant) in 46 (61.3%) and 16 (21.4%) patients respectively. Overall 5 year survival was 24% and median survival for patients with and without metastases was 21±17 and 75±10 months. Conclusion: Presence of metastases, age at diagnosis, positive surgical margin and tumor size were the prognostic factors that influenced outcome of patients. This study suggests that radiation therapy is an acceptable local treatment modality in patients with Ewing sarcoma family.

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Background: Dose calculation algorithms play a very important role in predicting the explicit dose distribution. We evaluated the percent depth dose (PDD), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calculation algorithms and inhomogeneity correction methods. Materials and Methods: The homogeneous and inhomogeneous virtual slab phantoms used in this study were manufactured in the radiation treatment planning system to represent the air, lung, and bone density with planned radiation treatment of 6 MV photons, a field size of 10 × 10 cm², and a source-to-surface distance of 100 cm. Results: The PDD of air density slab for the Acuros XB (AXB) algorithm was differed by an average of 20% in comparison with other algorithms. Rebuild up occurred in the region below the air density slab (10–10.6 cm) for the AXB algorithm. The lateral dose profiles for the air density slab showed relatively large differences (over 30%) in the field. There were large differences (20.0%–26.1%) at the second homogeneous–inhomogeneous junction (depth of 10 cm) in the field for all calculation methods. The surface dose volume histogram for the pencil beam algorithm showed a response that was approximately 4% lower than that for the AXB algorithm. Conclusion: The dose calculation uncertainties were shown to change at the interface between different densities and in varied densities using the dose calculation methods. In particular, the AXB algorithm showed large differences in and out of the field in inhomogeneous media.

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Background: Fatigue is a common side effect in cancer patients undergoing radiation therapy (RT). Radiation-induced fatigue affects the quality of life, but there is no definitive treatment option. In this study, the weight-loaded forced swim test was performed to assess the effect of coenzyme Q10 (CoQ10) on radiation-induced fatigue. Materials and Methods: A total of 60 rats were divided randomly and equally into four groups: No swim, No RT, RT + placebo, or RT + CoQ10. The No swim, No RT, and RT + placebo groups received 1 mL of soybean oil daily for 14 days. The RT + CoQ10 group received 100 mg/kg of CoQ10 in soybean oil at the same times. Both RT groups were irradiated with 10 Gy on the 14th day of treatment. The swim test with sinkers weighing 10% of body weight was performed 24 h later in all animals except the No swim group. Results: The level of blood urea nitrogen (BUN) was significantly lower in the No swim than the other groups. The BUN level of the No RT group was significantly decreased compared with the RT + placebo group, but it did not differ from the RT + CoQ10 group. Swimming times to complete exhaustion were significantly longer in the No RT and RT + CoQ10 groups compared to the RT + placebo group (99.4, 105.9, and 75.7 s, respectively) (P<0.001). Conclusion: Supplementation with CoQ10 can prevent the decrease in endurance capacity caused by radiation.  

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