background and aims. the antioxidant and anti-inflammatory properties of propolis were studied. since saliva contains antioxidants and radiotherapy of the head and neck mainly affects the saliva, salivary antioxidant defensive mechanism is compromised with oxidative stress produced by radiation therapy. therefore, the aim of the present study was to investigate the effect of propolis on salivar...

background: an effective method for management of large and bulky malignant tumors. this treatment modality is also known as specially fractionated radiation therapy (sfrt). in this treatment technique a grid block converted the open radiation field into a series of pencil beams. dosimetric characteristics of an external beam grid radiation field have been investigated using experimental and mo...

BACKGROUND Compared to static beam Intensity-Modulated Radiation Therapy (IMRT), the main advantage of Volumetric Modulated Arc Therapy (VMAT) is a shortened delivery time, which leads to improved patient comfort and possibly smaller intra-fraction movements. This study aims at a treatment planner-independent comparison of radiotherapy treatment planning of IMRT and VMAT for head-and-neck cance...

Background: The aim was to evaluate the benefit of technical advances for treatment planning: introduction of a hydrogel spacer, VMAT (volumetric modulated arc therapy) and a single biological organ at risk objective for the rectum and bladder. Initial standard was a step-and-shoot IMRT (intensity modulated radiotherapy) without a spacer and conventional organ at risk objectives.  Material...

background: the fundamental principles of internal targeted alpha therapy for cancer were established many decades ago.the high linear energy transfer (let) of alpha radiation to the targeted cancer cellscauses double strand breaks in dna. at the same time, the short range radiation spares adjacent normal tissues. this targeted approach complements conventional external beam radiotherapy and ch...

the cancer of oral cavity is related to lesions of mucous membrane of tongue and gum that can be treated with radiation therapy. a lateral photon field can be used to treat this kind of tumor, which has a side‑effect on normal tissue in the opposite side of the oral cavity. in this study the dosimetric effect of the various shields in oral cavity is evaluated. in this study, a special phantom s...

extra renal extra cranial malignant rhobdoid tumors (mrt) are rare, frequently lethal and affect mostly children. no definite treatment has been made and the role of radiation therapy is poorly defined. this report explains a 14 year old girl with mrt in her neck soft tissue. she is alive with no evidence of disease 18 months after diagnosis. through the experience with this case, we suggested ...

normal 0 false false false en-us x-none fa introduction: in radiation therapy centers across iran, protection of normal tissues is usually accomplished by either cerrobend or lead block shielding. in this study, the influence of these two shielding methods on central axis dose distribution of photon beam a cobalt unit was investigated in clinical conditions. materials and methods: all measureme...