background: hdr brachytherapy is one of the commonest methods of nasopharyngeal cancer treatment. in this method, depending on how advanced one tumor is, 2 to 6 gy dose as intracavitary brachytherapy is prescribed. due to high dose rate and tumor location, accuracy evaluation of treatment planning system (tps) is particularly important. common methods used in tps dosimetry are based on computat...

background: one of the means of assessing dose to patients from computed tomography (ct) procedure is through the determination of the skin entrance dose (esd) with the appreciation of the concern that ocular exposure effects from ct scan includes possible induction of cancer and cataract. due to the relatively more recent introduction of ct scans, little work has been done in this area in the ...

Despite the good general patient acceptance, high patient comfort, safety and precision in the needle placement, exposure to radiation in computed tomography (CT)-guided spinal interventions remains a serious concern, and is often used to argue against its use. The aim of this study was to determine the technical possibilities of reducing the radiation dose in CT-guided epidural and periradicul...

PURPOSE The volume CT dose index (CTDIvol) and the dose-length product, commonly reported for examinations performed on clinical CT scanners, should not be used as surrogates for patient dose. This is because significant under or overestimates of these actual values can occur when there is a mismatch between the actual body size of the patient and the 16 cm or 32 cm diameter CTDIvol phantoms. T...

Although there has been increasing recognition of the importance of reducing radiation dose when performing multidetector CT examinations, the increasing complexity of CT scanner technology, as well as confusion about the importance of many different CT scan parameters, has served as an impediment to radiologists seeking to create lower dose protocols. The authors seek to guide radiologists thr...

Computed Tomography (CT) procedures constitute the 5% of the total diagnostic radiology and provide more than the 40% of the total dose. Patient dose depends on many factors; most of them depend on the way the procedure is performed. All around the world, there is a growing interest in studying patient dose in CT procedures in order to optimize them. If the patient is pregnant, conceptus absorb...

Introduction: Becuase of the most radiation dose receiving by human is related to medical radiation exposures, and also Computed Tomography (CT) is a special type of radiography that is one of the main method of radiation exposure today, and it's growing increasingly. Therefore, radio technologists working in CT scan imaging centers, are at risk of radiation. Due to the high am...

Computed Tomography (CT) images taken during whole radiotherapy procedure is important for treatment planning, portal design and providing patient position. However, the dose received by in these CT scans are not included planning calculations. Especially adaptive treatments, from daily scan becomes very calculation of limit doses critical organs. In this study, with NCICT code, which use Monte...

Organ dose is the absorbed radiation energy from ionizing radiation to an organ, divided by the organ mass. Organ doses of a patient cannot be measured directly in the patient, but their determination requires dose measurements in anthropomorphic patient models i.e. phantoms or Monte Carlo simulations. Monte Carlo simulations can be performed for example by using computational phantoms or patie...

For all their diagnostic value, computed tomography (CT) examinations have relatively high radiation exposure. Past efforts to decrease patient dose emphasized advances in data acquisition technology because attempts to decrease dose resulted in increased image noise from filtered back projection reconstruction techniques. Iterative reconstruction techniques lead to reduced dose and maintain im...