The aim of this study was to evaluate the impact of actual rotational setup errors on dose distributions in intracranial stereotactic radiotherapy (SRT) with different alternatives for treatment position selection. A total of 38 SRT fractions from 18patients were retrospectively evaluated with rotational setup errors obtained from actual treatments. The planning computed tomography (CT) images ...

background: in this study, quantitative 32p bremsstrahlung planar and spect imaging and consequent dose assessment were carried out as a comprehensive phantom study to define an appropriate method for accurate dosimetry in clinical practice. materials and methods: ct, planar and spect bremsstrahlung images of jaszczak phantom containing a known activity of 32p were acquired. in addition, phanto...

Cone-beam computed tomography (CBCT) images have inaccurate CT numbers because of scattered photons. Thus, quantitative analysis of scattered photons that affect an electron density (ED) curve and calculated doses may be effective information to achieve CBCT-based radiation treatment planning. We quantitatively evaluated the effect of scattered photons on the accuracy of dose calculations from ...

introduction: during radiotherapy, high accuracy in the dose delivery is required because there is a strong  relationship between the absorbed dose, local tumor control and particularly the normal tissue damage. in  many institutions, in vivo dosimetry using diodes is performed to check the actual dose delivered. in general,  the uncertainty in the dose delivered should fall within  ± 5% of the...

Occipital neuralgia generally responds to medical or invasive procedures. Repeated invasive procedures generate increasing complications and are often contraindicated. Stereotactic radiosurgery (SRS) has not been reported as a treatment option largely due to the extracranial nature of the target as opposed to the similar, more established trigeminal neuralgia. A dedicated phantom study was cond...

Introduction: Esophageal cancer is one of the most frequently occurring cancers in Iran and having a  high  incidence  rate  among  other  countries.  Radiotherapy  is  one  of  the  three  methods  (surgery,  radiotherapy and chemotherapy) for radical or palliative treatment of esophageal cancer. In this method  of treatment, the organs such as heart and spinal cord are regarded as organs at r...

A theory is presented on dose calculations in inhomogeneous media that takes advantage of fast Fourier transform (FFT) convolution for practical 3-D treatment planning using photon beams. We derived a new correction dose formula which corrects the dose deposited by the Compton rst scattered photons due to the presence of inhomogeneities. We justiied theoretically why the convolution primary dos...

Introduction: In radiation therapy, the accuracy of dose calculations by a treatment planning system (TPS) is important to achieve tumor control and to spare normal tissue. Treatment planning system calculations in the heterogeneous situation may present significant inaccuracies. In this study, three different dose calculation algorithms, pencil beam (PB), collapsed cone (CC), ...

  Introduction: Radioiodine (131I) is an effective and inexpensive alternative to surgery in the treatment of thyroid hyperfunction. The debate today concerns the maximum and minimum ablative doses, and factors leading to hypothyroidism. Patients & Method: 1035 hyperthyroid patients treated with weight-adjusted ablative doses of 131I were retrospectively assessed for ...