Clinical implementation and rapid commissioning of an EPID based in-vivo dosimetry system.
Phys Med Biol
; 59(19): N171-9, 2014 Oct 07.
Article
em En
| MEDLINE
| ID: mdl-25211121
ABSTRACT
Using an Electronic Portal Imaging Device (EPID) to perform in-vivo dosimetry is one of the most effective and efficient methods of verifying the safe delivery of complex radiotherapy treatments. Previous work has detailed the development of an EPID based in-vivo dosimetry system that was subsequently used to replace pre-treatment dose verification of IMRT and VMAT plans. Here we show that this system can be readily implemented on a commercial megavoltage imaging platform without modification to EPID hardware and without impacting standard imaging procedures. The accuracy and practicality of the EPID in-vivo dosimetry system was confirmed through a comparison with traditional TLD in-vivo measurements performed on five prostate patients.The commissioning time required for the EPID in-vivo dosimetry system was initially prohibitive at approximately 10 h per linac. Here we present a method of calculating linac specific EPID dosimetry correction factors that allow a single energy specific commissioning model to be applied to EPID data from multiple linacs. Using this method reduced the required per linac commissioning time to approximately 30 min.The validity of this commissioning method has been tested by analysing in-vivo dosimetry results of 1220 patients acquired on seven linacs over a period of 5 years. The average deviation between EPID based isocentre dose and expected isocentre dose for these patients was (-0.7 ± 3.2)%.EPID based in-vivo dosimetry is now the primary in-vivo dosimetry tool used at our centre and has replaced nearly all pre-treatment dose verification of IMRT treatments.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Neoplasias da Próstata
/
Garantia da Qualidade dos Cuidados de Saúde
/
Radiometria
/
Imagens de Fantasmas
/
Eletrônica
Tipo de estudo:
Prognostic_studies
Limite:
Humans
/
Male
Idioma:
En
Revista:
Phys Med Biol
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Reino Unido