An alternative pseudo CT generation method for magnetic resonance image (MRI)-based radiotherapy planning was investigated in the work. A pseudo CT was initially generated using the rigid image registration between the planning MRI and previously acquired diagnostic CT scan. The pseudo CT generated was then refined to have the same morphology with that of the referenced planning image scan by a...

The ultimate check of the actual dose delivered to a patient in radiotherapy can only be achieved by using in vivo dosimetry. This work reports a pilot study to test the applicability of a thermoluminescent dosimetric system for performing in vivo entrance dose measurements in external photon beam radiotherapy. The measurements demonstrated the value of thermoluminescent dosimetry as a treatmen...

In this paper, a numerical study to assess the dosimetry of an in vitro exposure setup at the intermediate frequencies (IF) is presented and validated. The setup is able to reproduce any complex magnetic induction (B) field waveform using a couple of square coils. In our work, actual signals generated by a 1.5 T magnetic resonance imaging (MRI) apparatus were exploited. Firstly, the simulated B...

Magnetic resonance (MR) imaging of Gafchromic film causes perturbation to absolute dosimetry measurements; the purpose of this work was to characterize the perturbation and develop a correction method for it. Three sets of Gafchromic EBT2 film were compared: radiation (control), radiation followed by MR imaging (RAD + B), and MR imaging followed by radiation (B + RAD). The T1-weighted and T2-we...

1. Introduction Since it is very difficult to quantify microwave absorption directly in a living human, dosimetry is forced to rely mainly on computer simulation with high-resolution numerical human models obtained from magnetic-resonance imaging (MRI) or computed tomography (CT) scans. The Finite-Difference Time-Domain (FDTD) method [1] is currently the most widely accepted means for the numer...

Current HIFU challenges include amount of tissue that can be destroyed by a single exposure, the inability to treat through bone, difficulty in monitoring therapy in real‐time, and difficulty in planning the strategy before therapy. Technological advances such as multi‐transducer or array beam generator, instrumentation and image‐based guidance of HIFU treatment promise to overcome many of thes...

BACKGROUND Infringement by differentiated thyroid carcinoma on the brain is rare but, when suspected, the patient deserves special attention. A patient with an enlarging metastasis of thyroid carcinoma to the skull that was impinging on the brain illustrates diagnostic and therapeutic strategies applicable to the treatment of metastatic carcinoma. METHODS A case study was performed. Computed ...

BACKGROUND Polymer gel dosimeters combined with magnetic resonance imaging (MRI) can be used for dose verification of advanced radiation therapy techniques. However, the uncertainty of dose map measured by gel dosimeter should be known. The purpose of this study is to investigate the uncertainty related to calibration curve and MRI protocol for MAGIC (Methacrylic and Ascorbic acid in Gelatin In...