Background: In this study, a comparison between various types of radiotherapy treatment for parotid gland cancer was performed to achieve the optimal treatment technique.Methods: Treatment planning and countering performed with TiGRT software for 15 patents with parotid gland cancer. Six techniques were performed and compared. Finally, by comparing the dose volume histograms (DVH), average dose received by each organ was determined and the best method was introduced. Techniques were as: 1. an ipsilateral wedge pair technique using 6 MV photons; 2. a 3-field anteroposterior (AP) (wedged) posteroanterior (PA) (wedged) and lateral portal technique using 6 MV photons; 3. a mixed beam technique using 6 MV photons and 12 MeV electrons (1: 4 weighting); 4. a mixed beam technique using 6 MV photons and 15 MeV electrons (1: 4 weighting); 5: four 6 MV photon beams with different gantry angles; and 6. similar to fifth technique with an additional small ring around the tumor tissue. Findings: Intensity-modulated arc therapy (IMRT) techniques five and six delivered maximum dose to the target and minimum dose to organ at risks (OAR). Among 3-D conformal radiotherapy techniques (CRT), technique number two delivered more amount of dose to the target than techniques number three and four. The dose delivered to the contrary parotid gland was negligible for intensity-modulated arc therapy techniques.Conclusion: Intensity-modulated arc therapy techniques are most appropriate methods for treating cancer of the parotid gland and the sixth technique delivered better dose distribution in the tumor and healthy tissues. Second D conformal radiotherapy technique delivered higher average dose to the target.

Background: Intensity-Modulated RADIATION Therapy (IMRT) is one of the best methods in the treatment of optic nerve sheath meningioma (ONSM) with tumor growth control and visual stabilization. In this study, various IMRT techniques were evaluated from the point of view of dose fall-off beyond the target boundaries to achieve the optimal technique. Methods: The optimization of 3 IMRT techniques was performed using 3, 5, and 7 fields with 6 MV photons in 15 patients with ONSM using Prowess Panther treatment planning system. To evaluate treatment plans, in addition to data extracted from dose-volume histogram (DVH) and evaluation of target coverage indices, differential and cumulative dose gradient indices (DGIs) were calculated and compared between the three techniques. Findings: The maximum and the mean dose received by the tumor increased with increasing number of IMRT fields. The uniformity (UI) and homogeneity (HI) indices were significantly different between the 3-field and 7-field techniques; and the conformity index (CI) was close to ideal value (0. 99) in 7-field technique. Difference of differential dose gradient index (dDGI) was negligible between the three techniques, and only at the 45% isodose level, there was a significant difference between the 5-and 7-field techniques. Cumulative dose gradient index (cDGI) showed smaller values in 7-field technique than the other two techniques. Conclusion: The three IMRT techniques have no considerable statistical difference in dose fall-off rate beyond tumor boundaries; and their choice in the treatment of ONSM depends on the physician's discretion based on the whole patient's conditions.

Introduction & Background: Today, radiotherapy alone or in combination with other therapeutic methods for treatment of various cancers is very effective and has a special place in medicine. This treatment modality is used in two ways, in combination with radiopharmaceuticals and in the vicinity of tumors, or by irRADIATION of tumor bed from an external source. One of the unwanted effects of this type of treatment is its effect on the musculoskeletal sys-tem. Considering the better long term survival of cancer patients and the appearance of late-onset side effects of those malignancies, knowledge about the effects of radiotherapy on the musculoskeletal system and the methods of differentiating them from secondary involvement by malignant diseases, has gained significant importance.

RADIATION, as a means of food preservation, was first discussed in 1905. In this method, food is exposed to a certain doze of ionizing ray with the purpose of destroying or deactivating microorganisms and insects, delaying the procedure of ripening of fruits and vegetables, preventing glandular and root vegetables from new shooting, and in general, increasing the period of preservation under certain conditions.

Introduction: Ionizing RADIATIONs are the hazardous agents in the workplace and all forms of ionizing RADIATION produce some type of injuries. Awareness of application of protection guidelines and knowledge of the principles of RADIATION protection can play an important role in health of employees. Survey of RADIATION employee’s levels of awareness and practical behavior is essential and should be standardized. Methods: The hospitals were visited to determine the number of RADIATION employees and to select the samples. Data was collected by questionnaire and analyses were performed by EPI6 software. Results: The employee’s awareness about protection in the RADIATION room was 70%, about application of film badge was more than 85%. The employee’s awareness of periodic inspection of atomic energy organization expert was 54% and their  knowledge of long term and short term RADIATION effects were 98% and 95%, respectively. There was a meaningful relation concerning the level of education and awareness of the employees about MPD or principles of RADIATION protection (P<0.0007 and P<0.003 respectively). Conclusion: Our results reveal that the employees have acceptable knowledge about the use of film badges, however, they lack enough awareness concerning other issues of RADIATION protection. Proper and periodic educational courses for RADIATION workers are mandatory.

Background: This study aimed to determine hippocampal absorbed dose in radiotherapy of high-grade brain glioma using dose painting method and to compare it with intensity-modulated RADIATION therapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT).Methods: In Milad hospital radiotherapy section in Isfahan, Iran, images from 24 patients with high-grade brain glioma were acquired. All radiotherapy volumes for patients were defined and then, at risk organ was contoured. There were 4 planning target volumes (PTVs) defined for each patient. PTV4 just has been defined for dose painting method and the given dose was increased up to 72 Gy in this method. Finally for each patient, by using treatment planning system characteristics, 3 methods were simulated and the optimal technique was represented. Findings: The average hippocampus-received dose was 4.772, 4.174, and 5.668 Gy in 3D-CRT, IMRT, and dose painting methods, respectively. Increasing the dose in dose painting method by 1.2% than in IMRT method resulted in 1.357% increasing in hippocampal-absorbed dose; considering the hippocampal tolerance dose, it would not cause serious injury and in return tumors, would be controlled more effectively.Conclusion: In this study, the importance of multi-parametric magnetic resonance imaging (MRI) in dose painting method was achieved. As by using these images for determining the different parts of tumor, tumor-received dose significantly increased; while the organs around the tumor received no serious damage.

Background: According to the RADIATION hormesis hypothesis, low-dose ionizing RADIATION is not only dangerous, but also can even reduce the number of cancers in the irradiated community. The aim of this study was to evaluate RADIATION hormesis in the field of radiology. Methods: The search was conducted through Science Direct, Scopus, PubMed, EMBASE, Google Scholar, and Web of science databases using the keywords of Ionizing RADIATION, Dose response, Hormesis, Low-dose RADIATION, Radiology, RADIATION worker, and Patient in the period of 1990-2019. Findings: In the early stages of the search, 1230 studies were found in databases. Finally, by reviewing the titles and abstracts of the articles, there were 38 articles related to the research topic. After careful consideration, four main areas were categorized including genetics area with 14 articles, cell area with 16 articles, animal area with 2 articles, and human area with 6 articles. Conclusion: The effect of RADIATION hormesis has been rejected in some studies and confirmed in some others; but has not been demonstrated in RADIATION conditions similar to those found in radiology for patients and RADIATION workers. To confirm or disapprove this dose response model, detailed studies should be performed on RADIATION conditions such as different radiological tests in terms of beam type, beam energy, dose, and RADIATION dose rate.