Academic literature on the topic 'Radiotherapy data processing; radiation dosage; radiation dosimetry'

<p class="Default">It is essential to know the standard dose rate, output of Co-60 source in the radiation treatment periodically. It is because the over dosage may cause radiation hazards where as under dosage may lead to unsatisfactory treatment of cancer. Present study focused on the radiation standards and dosimetry for the assurance of the quality and verify that the output of the ionizing radiation emitting medical instruments such as Teletherapy Unit (TTU) which should be within ±2% of the stated one. Present study was done as a part of the regularity of quality assurance (QA) of telecobalt radiotherapy unit that includes the dosimetric measurements of Co-60 TTU at Bhaktapur Cancer Hospital (BCH), Bhaktapur per each month from 29 March 2012 to 29 December 2014. The radionuclide source is Co-60 which has been incorporated in TTU, BCH for the purpose of therapeutic treatment of cancer. The Co-60 source decays continuously to Ni-60 (half-life of 5.27 years) with the decrease in its activity and hence the output dose rate. The calculations of actual dose rate of Co-60 TTU were done by the source to surface distance (SSD) technique. It has been concluded that there is a quality assurance management in Co-60 TTU, BCH with the consistency in the average output dose rate obtained by the actual dosimetry values and the expected output values obtained by decay method. The values obtained by actual dosimetry are within ±2% of the expected values so that the deviation of the actual output dose rate from the expected output data lies within the permissible limit as prescribed by International Atomic Energy Agency (IAEA) and International Commission on Radiation Units and Measurement (ICRUM). In conclusion, our study shows a trend towards uniform and better dose delivery from Co-60 TTU, BCH, Nepal</p><p><strong>Journal of Nepal Physical Society</strong><em><br /></em>Volume 4, Issue 1, February 2017, Page: 88-92</p>

Abstract Neuroblastoma (NB) is a common type of cancer found mostly in infants and arising from the immature neural crest cells of the sympathetic nervous system. Using laser trapping (LT) technique, the present work contributes to advancing radiotherapy (RT), a leading treatment method for cancer. A single, 2-cells, 3-cells, 4-cells, and 5-cells were trapped using the high-intensity gradient infrared laser at 1064 nm and allowed to become ionized. In this work, a systematic study of Threshold Ionization Energy (TIE) and Threshold Radiation Dose (TRD) versus mass for both single and multi-cell ionization using laser trapping (LT) techniques on NB is presented. The results show that TIE increased as the mass of cells increased, meanwhile TRD decreased with the increase of cell mass. We observed an inverse correlation between TRD and cell mass. We demonstrate how to compute the maximum radiation dosage for cell death using the LT technique. Results show a possible blueprint for computing the TRD in vivo. The use of multiple cell ionization to determine radiation dosage along with better data accuracy concerning the tumor size and density will have profound implications for radiation dosimetry. The diminution in TRD becomes more significant in multiple cell ionization as we see in TRD vs the number of cells entering the trap. This is due to the chain effect generated by radiation and the absorption by water molecules at 1064 nm. This result provides us with better insight into the optimization of the therapeutic ratio.

Made available in DSpace on 2014-10-09T12:28:40Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T13:56:02Z (GMT). No. of bitstreams: 0
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

With IMRT now the future for the accurate delivery of radiation therapy, an investigation into the beam delivery system and the radiotherapy planning system has been undertaken to determine the accuracy and limitations of both systems. Results outlined in the following investigation have shown limitations in the beam delivery system as a result of the individual leaf construction and the Linac mechanics. Results from this investigation have shown limitations applied to IMRT fluence conversion and machine delivery process must include a minimum 2cm equivalent segment size with the smallest possible secondary collimator setting encompassing all segments, 400 MU/min dose rate and 4MU/segment to provide optimum IMRT delivery employing the Pinnacle³ planning system and the varian 600CD LINAC. Appying these limitations was also shown to minimize the effects due to the leaf construction.
Thesis (M.Sc.(Med.Physics)) -- University of Adelaide, School of Chemistry and Physics, 2007