Background: Medical x-rays are the largest man-made source of public exposure to ionizing radiation. It is important to avoid conditions where the amount of radiation used is more than that needed for the procedure. Materials and Methods: The Entrance Skin Exposure (ESE) measurement was conducted for quality control of x-ray machines and survey of operator’s experimental techniques. The ESEs we...

In this study, we evaluate dosimetric advantages of using patient-specific aperture system with intensity-modulated proton therapy (IMPT) for head and neck tumors at the shallow depth. We used four types of patient-specific aperture system (PSAS) to irradiate shallow regions less than 4 g/cm2 with a sharp lateral penumbra. Ten head and neck IMPT plans with or without aperture were optimized sep...

background: in helical tomotherapy (ht), the scaling factor (sf) is the time in seconds that each leaf viewing a target would need to be open to deliver the prescribed dose. the sf is patient-specific and is used to calculate the rotational period of the gantry, and the total treatment time (ttt) of the ht. the sf is generally difficult to estimate. currently, it takes about one hour to fully o...

Current estimation of radiation dose from computed tomography (CT) scans on patients has relied on the measurement of Computed Tomography Dose Index (CTDI) in standard cylindrical phantoms, and calculations based on mathematical representations of "standard man". Radiation dose to both adult and pediatric patients from a CT scan has been a concern, as noted in recent reports. The purpose of thi...

Abstract Tumor Treating Fields (TTFields) are electric fields that disrupt cellular processes critical for cancer cell viability and tumor progression. TTFields administered through two pairs of capacitive arrays placed on the patient’s scalp. The effect has been shown to be dose dependent. An in-silico study based imaging survival data from phase 3 EF-14 demonstrated a correlation between simu...

Background: With the introduction of computed tomography in diagnostic radiology a new and fundamentally different imaging modality has become available. Meanwhile, it is clear that the absorbed doses by the patients during CT were relatively high in comparison with those of other diagnostic radiology techniques. The aim of this survey was to determine the average absorbed dose in Yazd provin...

conclusions the effective annual dose of interventionists who work in center 1 and 2 was 143.08 and 1226.78 msv respectively. the high radiation dose which delivers to the leg of physicians in center 2 can be an important cause of radiation dermatitis occurred on the leg of our interventionist. patient dose during most of the procedures was less than the threshold dose for occurring erythema bu...

Introduction: In 2000, the UNSCEAR reported that CT constitutes 5% of all the medical x-ray  examinations and it contributes 34% of the resultant collective dose worldwide. Children are more  sensitive to the ionizing radiations than adults. So, routine quality control tests are expected to be  carried out periodically on the CT scanners. The aim of this research was to estimate the effective  ...