An experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour

In the recent years, improvements in imaging technology have allowed for the detection of small tumours in patients. These small tumours that can be found in areas such as the lung can be treated with Stereotactic Body Radiotherapy (SBRT), which requires high accuracy in dose delivery with the high...

Full description

Saved in:
Bibliographic Details
Main Author: Lee, Wen Han
Other Authors: -
Format: Final Year Project
Language:English
Published: Nanyang Technological University 2022
Subjects:
Online Access:https://hdl.handle.net/10356/156954
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-156954
record_format dspace
spelling sg-ntu-dr.10356-1569542023-02-28T23:15:50Z An experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour Lee, Wen Han - School of Physical and Mathematical Sciences National Cancer Centre Singapore Lee Cheow Lei James trdjas@nccs.com.sg Science::Physics::Nuclear and particle physics In the recent years, improvements in imaging technology have allowed for the detection of small tumours in patients. These small tumours that can be found in areas such as the lung can be treated with Stereotactic Body Radiotherapy (SBRT), which requires high accuracy in dose delivery with the high doses used in the treatment. In this study, the accuracy of Anisotropic Analytical Algorithm (AAA) and Acuros XB (AXB) on small tumour targets in a heterogeneous lung phantom was explored. Water-equivalent tumour targets of 0.5 cm, 1 cm, 1.5 cm, 2 cm, and 3 cm were irradiated with square field sizes from 5 cm by 5 cm down to square field sizes with width that is the nearest integer value larger than the diameter of the target, using 10FFF, 10X, 6FFF and 6X photon beams. The same parameters were used to calculate doses in Varian Eclipse TPS (Eclipse Treatment Planning ver13.6, Varian Medical System, Inc, Ca, USA) using AAA and Acuros XB with grid sizes 0.25 cm and 0.1 cm. Doses were also predicted in the TPS with deviations of 3 mm in each axis to account for positional uncertainty during the alignment of the phantom. The results imply that field sizes alone do not greatly affect the accuracy of TPS algorithms. However, positional uncertainty plays a significant role in the accuracy of TPS, accounting up to 11.44% error from a 3 mm position deviation. As the field size decreases bear to the size of the tumour, the effects of positional uncertainty on dose accuracy of TPS becomes much more prominent. The tumour sizes also directly affect the accuracy of the TPS algorithms, where a smaller tumour size will increase the dose inaccuracy. This was deduced to be due to the robustness of dose calculation by the algorithms limited by the grid size used. FFF beams are recommended for SBRT as the dose predictions using FFF beams show a lower percentage error compared to the dose predictions done by using flattened beams. Bachelor of Science in Applied Physics 2022-05-04T03:17:58Z 2022-05-04T03:17:58Z 2022 Final Year Project (FYP) Lee, W. H. (2022). An experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour. Final Year Project (FYP), Nanyang Technological University, Singapore. https://hdl.handle.net/10356/156954 https://hdl.handle.net/10356/156954 en application/pdf Nanyang Technological University
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science::Physics::Nuclear and particle physics
spellingShingle Science::Physics::Nuclear and particle physics
Lee, Wen Han
An experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour
description In the recent years, improvements in imaging technology have allowed for the detection of small tumours in patients. These small tumours that can be found in areas such as the lung can be treated with Stereotactic Body Radiotherapy (SBRT), which requires high accuracy in dose delivery with the high doses used in the treatment. In this study, the accuracy of Anisotropic Analytical Algorithm (AAA) and Acuros XB (AXB) on small tumour targets in a heterogeneous lung phantom was explored. Water-equivalent tumour targets of 0.5 cm, 1 cm, 1.5 cm, 2 cm, and 3 cm were irradiated with square field sizes from 5 cm by 5 cm down to square field sizes with width that is the nearest integer value larger than the diameter of the target, using 10FFF, 10X, 6FFF and 6X photon beams. The same parameters were used to calculate doses in Varian Eclipse TPS (Eclipse Treatment Planning ver13.6, Varian Medical System, Inc, Ca, USA) using AAA and Acuros XB with grid sizes 0.25 cm and 0.1 cm. Doses were also predicted in the TPS with deviations of 3 mm in each axis to account for positional uncertainty during the alignment of the phantom. The results imply that field sizes alone do not greatly affect the accuracy of TPS algorithms. However, positional uncertainty plays a significant role in the accuracy of TPS, accounting up to 11.44% error from a 3 mm position deviation. As the field size decreases bear to the size of the tumour, the effects of positional uncertainty on dose accuracy of TPS becomes much more prominent. The tumour sizes also directly affect the accuracy of the TPS algorithms, where a smaller tumour size will increase the dose inaccuracy. This was deduced to be due to the robustness of dose calculation by the algorithms limited by the grid size used. FFF beams are recommended for SBRT as the dose predictions using FFF beams show a lower percentage error compared to the dose predictions done by using flattened beams.
author2 -
author_facet -
Lee, Wen Han
format Final Year Project
author Lee, Wen Han
author_sort Lee, Wen Han
title An experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour
title_short An experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour
title_full An experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour
title_fullStr An experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour
title_full_unstemmed An experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour
title_sort experiment validation of treatment plannning system dose calculation accuracy in heterogeneous lung tumour
publisher Nanyang Technological University
publishDate 2022
url https://hdl.handle.net/10356/156954
_version_ 1759856118692052992