Joana Lencart

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A careful analysis of geometry and source positioning influence in the activity measurement outcome of a nuclear medicine dose calibrator is presented for (99m)Tc. The implementation of a quasi-point source apparent activity curve measurement is proposed for an accurate correction of the activity inside several syringes, and compared with a theoretical(More)
BACKGROUND AND PURPOSE The Medical Physics Division of the Portuguese Physics Society (DFM_SPF) in collaboration with the IAEA, carried out a national auditing project in radiotherapy, between September 2011 and April 2012. The objective of this audit was to ensure the optimal usage of treatment planning systems. The national results are presented in this(More)
BACKGROUND Surgery of locally advanced and/or recurrent rectal cancer can be complemented with intra-operative electron radiation therapy (IOERT) to deliver a single dose of radiation directly to the unresectable margins, while sparing nearby sensitive organs/structures. Haemorrhages may occur and can affect the dose distribution, leading to an incorrect(More)
PURPOSE To study the impact of shielding elements in the proximity of Intra-Operative Radiation Therapy (IORT) irradiation fields, and to generate graphical and quantitative information to assist radiation oncologists in the design of optimal shielding during pelvic and abdominal IORT. METHOD An IORT system was modeled with BEAMnrc and EGS++ Monte Carlo(More)
For a number of biomedical applications, including the development of phantoms for quality control of radiotherapy treatments and dose determination, it is important to study the radiation response of the used materials, in order to distinguish the relevant dose distribution modifications from the artifacts caused by the phantom material when subjected to(More)
As radiotherapy practice and processes become more complex, the need to assure quality control becomes ever greater. At present, no international consensus exists with regards to the optimal quality control indicators for radiotherapy; moreover, few clinical audits have been conducted in the field of radiotherapy. The present article describes the aims and(More)
Computed tomography fluoroscopy (CTF) is a useful imaging technique to guide biopsies, particularly lung biopsies, but it also has the potential for very high hand exposures, despite use of quick-check method and needle holders whenever feasible. Therefore, reliable monitoring is crucial to ensure the safe use of CTF. This is a challenge, because ring(More)
After publication of this study [1], the authors noticed that the funding was incorrectly acknowledged. The correct Acknowledgements section can be found below: “This work was partly funded by Fundação para a Ciência e Tecnologia (FCT), in the framework of the project PTDC/SAU-ENB/117631/2010, which is cofinanced by FEDER, through Programa Operacional(More)
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