A geometry based optimization algorithm for conformal external beam radiotherapy

Schreibmann, E; Lahanas, M; Uricchio, R; Theodorou, K; Kappas, C; Baltas, D

dc.contributor.author	Schreibmann, E	en
dc.contributor.author	Lahanas, M	en
dc.contributor.author	Uricchio, R	en
dc.contributor.author	Theodorou, K	en
dc.contributor.author	Kappas, C	en
dc.contributor.author	Baltas, D	en
dc.date.accessioned	2014-03-01T01:18:31Z
dc.date.available	2014-03-01T01:18:31Z
dc.date.issued	2003	en
dc.identifier.issn	0031-9155	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/15063
dc.subject.classification	Engineering, Biomedical	en
dc.subject.classification	Radiology, Nuclear Medicine & Medical Imaging	en
dc.subject.other	Algorithms	en
dc.subject.other	Biological organs	en
dc.subject.other	Dosimetry	en
dc.subject.other	Optimization	en
dc.subject.other	Tumors	en
dc.subject.other	Collimators	en
dc.subject.other	Radiotherapy	en
dc.subject.other	algorithm	en
dc.subject.other	article	en
dc.subject.other	collimator	en
dc.subject.other	controlled study	en
dc.subject.other	correlation analysis	en
dc.subject.other	dosimetry	en
dc.subject.other	geometry	en
dc.subject.other	head tumor	en
dc.subject.other	human	en
dc.subject.other	intermethod comparison	en
dc.subject.other	male	en
dc.subject.other	organ	en
dc.subject.other	priority journal	en
dc.subject.other	prostate cancer	en
dc.subject.other	radiation beam	en
dc.subject.other	radiation dose	en
dc.subject.other	radiation dose distribution	en
dc.subject.other	radiation exposure	en
dc.subject.other	treatment planning	en
dc.subject.other	Algorithms	en
dc.subject.other	Biophysics	en
dc.subject.other	Brain Neoplasms	en
dc.subject.other	Humans	en
dc.subject.other	Male	en
dc.subject.other	Phantoms, Imaging	en
dc.subject.other	Prostatic Neoplasms	en
dc.subject.other	Radiotherapy Planning, Computer-Assisted	en
dc.subject.other	Radiotherapy, Conformal	en
dc.title	A geometry based optimization algorithm for conformal external beam radiotherapy	en
heal.type	journalArticle	en
heal.identifier.primary	10.1088/0031-9155/48/12/311	en
heal.identifier.secondary	http://dx.doi.org/10.1088/0031-9155/48/12/311	en
heal.language	English	en
heal.publicationDate	2003	en
heal.abstract	A geometric solution of the problem of optimal orientation of beams in conformal external radiotherapy is presented. The method uses geometric derived quantities which consider the intersection volume between organs at risk (OAR) and the beam shape. In comparison to previous geometric methods a true 3D volume computation is used which takes into account beam divergence, concave shapes, as well as treatment settings such as individual beam shaping by blocks or multi-leaf collimators. For standard dosimetric cost functions used by dose optimization algorithms a corresponding set of geometric objective functions is proposed. We compare the correlations between geometric and dosimetric cost functions for two clinical cases, a prostate and a head tumour case. A correlation is observed for the prostate case, whereas for the head case it is less pronounced due to the larger part of overlapping volumes between the beams which cannot be considered by the used objectives. In comparison to not-optimized beam directions the dose distribution is significantly better for the beam directions found by the optimization of a geometric multi-objective cost function. An optimal dose distribution can easily be achieved using the geometric model. This is shown by comparing for the two cases the dose-volume histograms (DVH) of manually optimized plans by experienced planners and the DVHs of the geometrically found optimal solutions. In comparison to the manually optimized plans the solutions found by the geometric method significantly reduce the average dose in the OARs and NT, while maintaining the same PTV coverage.	en
heal.publisher	IOP PUBLISHING LTD	en
heal.journalName	Physics in Medicine and Biology	en
dc.identifier.doi	10.1088/0031-9155/48/12/311	en
dc.identifier.isi	ISI:000184063200011	en
dc.identifier.volume	48	en
dc.identifier.issue	12	en
dc.identifier.spage	1825	en
dc.identifier.epage	1841	en