The effect of patient inhomogeneities in oesophageal 192Ir HDR brachytherapy: A Monte Carlo and analytical dosimetry study

Anagnostopoulos, G; Baltas, D; Pantelis, E; Papagiannis, P; Sakelliou, L

dc.contributor.author	Anagnostopoulos, G	en
dc.contributor.author	Baltas, D	en
dc.contributor.author	Pantelis, E	en
dc.contributor.author	Papagiannis, P	en
dc.contributor.author	Sakelliou, L	en
dc.date.accessioned	2014-03-01T01:21:37Z
dc.date.available	2014-03-01T01:21:37Z
dc.date.issued	2004	en
dc.identifier.issn	0031-9155	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/16271
dc.subject	Monte Carlo	en
dc.subject.classification	Engineering, Biomedical	en
dc.subject.classification	Radiology, Nuclear Medicine & Medical Imaging	en
dc.subject.other	Backscattering	en
dc.subject.other	Dosimetry	en
dc.subject.other	Geometry	en
dc.subject.other	Monte Carlo methods	en
dc.subject.other	Patient monitoring	en
dc.subject.other	Patient treatment	en
dc.subject.other	Pulmonary diseases	en
dc.subject.other	Spinal cord	en
dc.subject.other	Treatment planning systems (TPS)	en
dc.subject.other	Biomedical engineering	en
dc.subject.other	iridium 192	en
dc.subject.other	water	en
dc.subject.other	algorithm	en
dc.subject.other	analytic method	en
dc.subject.other	article	en
dc.subject.other	beam therapy	en
dc.subject.other	brachytherapy	en
dc.subject.other	calculation	en
dc.subject.other	clinical practice	en
dc.subject.other	computer program	en
dc.subject.other	computer system	en
dc.subject.other	controlled study	en
dc.subject.other	dosimetry	en
dc.subject.other	esophagus	en
dc.subject.other	geometry	en
dc.subject.other	histogram	en
dc.subject.other	intermethod comparison	en
dc.subject.other	lung	en
dc.subject.other	materials	en
dc.subject.other	mathematical model	en
dc.subject.other	Monte Carlo method	en
dc.subject.other	phantom	en
dc.subject.other	prediction	en
dc.subject.other	priority journal	en
dc.subject.other	radiation dose	en
dc.subject.other	radiation dose distribution	en
dc.subject.other	radiation scattering	en
dc.subject.other	radiobiology	en
dc.subject.other	spinal cord	en
dc.subject.other	sternum	en
dc.subject.other	target organ	en
dc.subject.other	treatment planning	en
dc.subject.other	vertebra	en
dc.subject.other	Algorithms	en
dc.subject.other	Body Burden	en
dc.subject.other	Brachytherapy	en
dc.subject.other	Computer Simulation	en
dc.subject.other	Esophageal Neoplasms	en
dc.subject.other	Humans	en
dc.subject.other	Iridium Radioisotopes	en
dc.subject.other	Models, Biological	en
dc.subject.other	Models, Statistical	en
dc.subject.other	Monte Carlo Method	en
dc.subject.other	Radiometry	en
dc.subject.other	Radiotherapy Dosage	en
dc.subject.other	Radiotherapy Planning, Computer-Assisted	en
dc.subject.other	Relative Biological Effectiveness	en
dc.subject.other	Reproducibility of Results	en
dc.subject.other	Sensitivity and Specificity	en
dc.title	The effect of patient inhomogeneities in oesophageal 192Ir HDR brachytherapy: A Monte Carlo and analytical dosimetry study	en
heal.type	journalArticle	en
heal.identifier.primary	10.1088/0031-9155/49/12/014	en
heal.identifier.secondary	http://dx.doi.org/10.1088/0031-9155/49/12/014	en
heal.language	English	en
heal.publicationDate	2004	en
heal.abstract	The effect of patient inhomogeneities surrounding the oesophagus on the dosimetry planning of an upper thoracic oesophageal 192Ir HDR brachytherapy treatment is studied. The MCNPX Monte Carlo code is used for dosimetry in a patient-equivalent phantom geometry and results are compared in terms of isodose contours as well as dose volume histograms with corresponding calculations by a contemporary treatment planning system software featuring a full TG-43 dose calculation algorithm (PLATO BPS version 14.2.4). It is found that the presence of patient inhomogeneities does not alter the delivery of the planned dose distribution to the planning treatment volume. Regarding the organs at risk, the common practice of current treatment planning systems (TPSs) to consider the patient geometry as a homogeneous water medium leads to a dose overestimation of up to 13% to the spinal cord and an underestimation of up to 15% to the sternum bone. These findings which correspond to the dose region of about 5-10% of the prescribed dose could only be of significance when brachytherapy is used as a boost to external beam therapy. Additionally, an analytical dosimetry model, which is efficient in calculating dose in mathematical phantoms containing inhomogeneity shells of materials of radiobiological interest, is utilized for dosimetry in the patient-equivalent inhomogeneous phantom geometry. Analytical calculations in this work are in good agreement with corresponding Monte Carlo results within the bone inhomogeneities of spinal cord and sternum bone but, like treatment planning system calculations, the model fails to predict the dose distribution in the proximal lung surface as well as within the lungs just as the TPS does, due to its inherent limitation in treating lateral scatter and backscatter radiation. © 2004 IOP Publishing Ltd.	en
heal.publisher	IOP PUBLISHING LTD	en
heal.journalName	Physics in Medicine and Biology	en
dc.identifier.doi	10.1088/0031-9155/49/12/014	en
dc.identifier.isi	ISI:000222642700014	en
dc.identifier.volume	49	en
dc.identifier.issue	12	en
dc.identifier.spage	2675	en
dc.identifier.epage	2685	en