This work investigated the possibility of using proton beam for total body irradia-tion (TBI). We hypothesized the broad-slow-rising entrance dose from a monoen-ergetic proton beam can deliver a uniform dose to patient with varied thickness. Comparing to photon-based TBI, it would not require any patient-specific com-pensator or beam spoiler. The hypothesis was first tested by simulating 250 Me...

Background: Intraoral radiographies are the most frequent X-ray examinations in humans. According to International Commission on Radiation Protection (ICRP) recommendations, the selection of a diagnostic reference level (DRL) should be specific to a country or region. Critica l organs such as thyroid gland are exposed to X-rays in intraoral radiography and these exposures should be kept as low ...

Background: The anatomic position and proven radiosensitivity of the thyroid make it an organ of concern in dental X-ray examinations. A National Radiation Protection Department (NRPD)-sponsored pilot study carried out in the Dental Radiology Department of RUMS., to assess if the radiation dose in panoramic radiographies could be reduced without significant impairment of the subjective image qu...

We studied the performance of three computed radiography and three direct radiography systems with regard to the image noise and entrance skin dose based on a chest phantom. Images were obtained with kVp of 100, 110, and 120 and mA settings of 1, 2, 4, 8, and 10. Significant differences of image noise were found in these digital chest radiography systems (P<.0001). Standard deviation was signif...

Neutron and photon dose equivalents at various points along the mazes of the vaults for two 15 MV linear accelerators were measured. The measurements were made with the machines set at various gantry angles with and without the scattering phantom, and with the collimators set at the maximum and the minimum field sizes. Neutron dose equivalent measurements were made for five other accelerator va...

Patient dosimetry is performed in radiology and interventional radiology to assess whether deterministic injuries may occur and to establish the risk of stochastic effects. A fundamental problem for patient dosimetry is that no single quantity can be used to accurately assess both the risk of stochastic effects and whether deterministic injuries will occur following a specific examination or pr...

In contrast to x-rays, protons have a low entrance dose, a well-defined high-dose plateau (“Bragg peak”), and no exit dose beyond the target tissue. These properties make them ideal for treating localized cancers in areas surrounded by doselimiting normal structures. Their routine use required the creation of dedicated medical treatment centers which have only been in existence since the early ...

The determination of the dose delivered to the body during Total Body Irradiation (TBI) is not easy, as direct measurements are impossible. This article presents the intention to develop a systematic and simple method for absorbed dose determination in(60)Co TBI using mid plane dose factors (MDF) and external measurements, i.e. entrance and exit dose readings by semiconductor detectors. In orde...

In proton therapy, high dose rates can reduce treatment delivery times, allowing for efficient mitigation of tumor motion, as well increased efficiency and patient throughput. cyclotron-based facilities, however, are difficult to achieve at low-energies. current the emittance after degrader is matched in both transversal planes using circular collimators; this does not provide an optimal matchi...

Fig 1: Comparison of the depth dose profiles of proton and photon beams. The photon dose falls off exponentially with depth (green curve). A mono-energetic proton beam is characteriled by the presence of the Bragg peak in the region where the protons stop (red profile). Through the superposition (blue curve) of many proton beams of different residual range it is possible to deposit a homogenous...