Peripheral doses in patients undergoing Cyberknife treatment for intracranial lesions. A single centre experience

<p>Abstract</p> <p>Background</p> <p>Stereotactic radiosurgery/radiotherapy procedures are known to deliver a very high dose per fraction, and thus, the corresponding peripheral dose could be a limiting factor for the long term surviving patients. The aim of this clinical study was to measure the peripheral dose delivered to patients undergoing intracranial Cyberknife treatment, using the MOSFET dosimeters. The influence of the supplemental shielding, the number of monitor units and the collimator size to the peripheral dose were investigated.</p> <p>Methods</p> <p>MOSFET dosimeters were placed in preselected anatomical regions of the patient undergoing Cyberknife treatment, namely the thyroid gland, the nipple, the umbilicus and the pubic symphysis.</p> <p>Results</p> <p>The mean peripheral doses before the supplemental shielding was added to the Cyberknife unit were 51.79 cGy, 13.31 cGy and 10.07 cGy while after the shielding upgrade they were 38.40 cGy, 10.94 cGy, and 8.69 cGy, in the thyroid gland, the umbilicus and the pubic symphysis, respectively. The increase of the collimator size corresponds to an increase of the PD and becomes less significant at larger distances, indicating that at these distances the PD is predominate due to the head leakage and collimator scatter.</p> <p>Conclusion</p> <p>Weighting the effect of the number of monitor units and the collimator size can be effectively used during the optimization procedure in order to choose the most suitable treatment plan that will deliver the maximum dose to the tumor, while being compatible with the dose constraints for the surrounding organs at risk. Attention is required in defining the thyroid gland as a structure of avoidance in the treatment plan especially in patients with benign diseases.</p

Dosimetry during intramedullary nailing of the tibia: Patient and occupational exposure

Background Intramedullary nailing under fluoroscopic guidance is a common operation. We studied the intraoperative radiation dose received by both the patient and the personnel

Evaluation of the Impact of an International Master of Advanced Studies in Medical Physics

The Master of advanced studies in Medical Physics (MMP) has been jointly organized since 2014 by the International Centre for Theoretical Physics (ICTP) and Trieste University and supported by the International Atomic Energy Agency (IAEA), through the work of the Dosimetry and Medical Radiation Physics Section (DMRP), Division of Human Health (NAHU) and the IAEA Technical Cooperation Programme. The MMP, offers one academic year of theoretical classes followed by one year of structured clinical training in hospitals. It aims at addressing the scarcity of formal education and training schemes for medical physics studies, through an internationally harmonized programme that provides graduates with an academic knowledge and practical skills and competencies, to effectively practice medical physics once back to their home countries and Regions. Adequate academic education and structured clinical training of medical physicists play an important role in ensuring the safe and effective use of nuclear technologies in the diagnosis and treatment of patients. To evaluate the impact of the MMP, an online survey was developed and distributed to the graduates of the first two cycles of the programme, in March 2017, considering different aspects contributing to the overall fulfilment of the MMP aims. Criteria comprised: the activity of the graduates before and after the MMP, return rate to their home country and work activities performed after the degree. Specific feedback was also analysed about the MMP programme. The analysis of the 22 received answers (85% of all graduates at the time of the survey) is presented in this article

Peripheral dose measurement in high-energy photon radiotherapy with the implementation of MOSFET

AIM: To study the peripheral dose (PD) from high-energy photon beams in radiotherapy using the metal oxide semiconductor field effect transistor (MOSFET) dose verification system

Comparison of pencil-type ionization chamber calibration results and methods between dosimetry laboratories

A comparison of calibration results and procedures in terms of air kerma length product, P-KL, and air kerma, K, was conducted between eight dosimetry laboratories. A pencil-type ionization chamber (IC), generally used for computed tomography dose measurements, was calibrated according to three calibration methods, while its residual signal and other characteristics (sensitivity profile, active length) were assessed. The results showed that the partial irradiation method is the preferred method for the pencil-type IC calibration in terms of P-KL and it could be applied by the calibration laboratories successfully. Most of the participating laboratories achieved high level of agreement ( GT 99%) for both dosimetry quantities (P-KL and K). Estimated relative standard uncertainties of comparison results vary among laboratories from 0.34% to 2.32% depending on the quantity, beam quality and calibration method applied. Detailed analysis of the assigned uncertainties have been presented and discussed. (C) 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved

Improvement of early detection of breast cancer through collaborative multi-country efforts: Medical physics component

Purpose: The International Atomic Energy Agency (IAEA) through a Coordinated Research Project on “Enhancing Capacity for Early Detection and Diagnosis of Breast Cancer through Imaging”, brought together a group of mammography radiologists, medical physicists and radiographers; to investigate current practices and improve procedures for the early detection of breast cancer by strengthening both the clinical and medical physics components. This paper addresses the medical physics component. Methods: The countries that participated in the CRP were Bosnia and Herzegovina, Costa Rica, Egypt, India, Kenya, the Frmr. Yug. Rep. of Macedonia, Mexico, Nigeria, Pakistan, Philippines, Slovenia, Turkey, Uganda, United Kingdom and Zambia. Ten institutions participated using IAEA quality control protocols in 9 digital and 3 analogue mammography equipment. A spreadsheet for data collection was generated and distributed. Evaluation of image quality was done using TOR MAX and DMAM2 Gold phantoms. Results: QC results for analogue equipment showed satisfactory results. QC tests performed on digital systems showed that improvements needed to be implemented, especially in thickness accuracy, signal difference to noise ratio (SDNR) values for achievable levels, uniformity and modulation transfer function (MTF). Mean glandular dose (MGD) was below international recommended levels for patient radiation protection. Evaluation of image quality by phantoms also indicated the need for improvement. Conclusions: Common activities facilitated improvement in mammography practice, including training of medical physicists in QC programs and infrastructure was improved and strengthened; networking among medical physicists and radiologists took place and was maintained over time. IAEA QC protocols provided a uniformed approach to QC measurements.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias Atómicas Nucleares y Moleculares (CICANUM