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Background and Objective: Several organization such as AAPM (American Association of Physicist in Medicine), ACR (American College of Radiology), ACMP (American College of Medical Physics) and ESTRO (European Society for Therapeutic Radiology and Oncology) recommended the need for periodic quality control procedure in radiation oncology. One of the best methods for quality control is in vivo dosimetry, while radiotherapy is performed. The aim of this study was to design and optimiz a protocol for the quality control of radiation treatment of patients with head and neck malignancy. Materials and Methods: In this case series study midle line dose was measured in vivo in conjunction with portal imaging in 19 patients that were treated using a Co-60 unit, in August and December 2007. Distribution of entrance and exit dose was determined using two diodes, off axis ratios and portal imaging together with a user code written in MATLAB. User code was applied to convert optical intensity of portal film to optical density. Midline dose was calculated in one centimeter intervals using entrance and exit dose with the Huyskens algorithm method. Results: The midline dose was calculated in 165 points. The mean and standard deviation between measured and prescribed dose was about 4.27±3.61%. In 110 points (66.66%), the deviation was less than 5% (2.27±1.37), in 41 points (24.84%) the mean deviation was between 5 and 10% (6.51±1.2) and in 14 points (8.48%) mean deviation was more than 10% (13.37±2.34). The maximum and minimum deviations were found in center of the field (2.6±1.63) and 5cm away from center of the field (7.24±4.86) respectively. Maximum and minimum deviations correspond to the equivalent field of 14cm2 (5.08±3.53) and 8cm2 (2.95±2.13) respectively. Conclusion: This study showed that using a portal detector in conjunction with two diodes is a simple and accurate method for daily quality control in radiotherapy. The data is acquired in this way can be used for evaluating the accuracy of treatment steps including determination of output of a treatment machine, quality control of a treatment planning system and precision of calculations and patient setup.

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Background and Objective: Radiotherapy is a main therapeutic regiment in the treatment of head and neck cancers. Radiation not only eradicate cancer but it also cause damage to healthy surrounding tissues, giving rise to objective and subjective problems. This study was done to evaluate the subjective complications of post radiation in patients with head and neck cancer. Methods: This descriptive –analytic study was carried out on 45 patients with head and neck cancer (28 males and 17 females) whom were gone under radiotherapy in Rasht, Iran. Subjective complications evaluated before, during, 1 month and 3 months after radiotherapy. Persian version of LENT-SOMA questionnaire was used. Pain, xerostomia, dysphagia, trismus and dysgeusia were recorded for each subject. Results: 80% of subjects experienced Pain. In the study period, pain intensity, frequency and analgesic consumption were belonging to ear and throat. One month after post radiation, pain intensity, frequency and analgesic consumption belong to ear, throat, jaw, mouth and teeth which were significantly more than 3 months after radiotherapy (P<0.05). One month after post treatment, xerostomia, dysphagia, trismus and dysgeusia were significantly more than 3 months after radiotherapy (P<0.05). Pain in ear and jaw had significant correlation with radiation dosage (P<0.05). Conclusion: Intensity of subjective complains were aggravated and merge one month after radiotherapy and can be reduced to nearly the initial stage of treatment, three months after radiotherapy.