A retrospective comparison of two different immobilization systems for radiotherapy of extremity soft tissue sarcomas and its influence on CTV-PTV margin.
J Egypt Natl Canc Inst
; 33(1): 27, 2021 Sep 27.
Article
em En
| MEDLINE
| ID: mdl-34568989
ABSTRACT
BACKGROUND:
On account of extremity wide range of movements and difficulty of reproducibility during irradiation of extremity sarcomas, assorted immobilization strategies are employed to eliminate setup errors. The study purpose was to compare the setup errors of the commonly used immobilization tools and to define planning target volume (PTV) margins for each device.METHODS:
A retrospective review comparing Vac-Loc™ and thermoplastic cast (Tcast) was conducted. On radiotherapy treatment, portal imaging was matched with the pre-treatment simulation imaging for both fixation tools. The isocenter shifts and total vector error (TVE) were compared. Random (σ) and systemic errors (Σ) were computed and PTV margins were defined.RESULTS:
Three hundred seven shifts in each direction measured in 14 patients. Mean displacements for the Vac-Loc™ and Tcast, respectively, were as follow vertical; -0.01 cm vs. 0.02 cm, longitudinal; 0.03 cm vs. 0.04; lateral; 0.04 cm vs. 0.00 cm and TVE; 0.15 cm vs. 0.17 cm with no significant statistical difference. Random and systemic errors were comparable for both devices. The lateral displacement and rotational random errors were higher Vac-Loc™ compared to Tcast. Overall measured PTV margins were marginally lower for Tcast compared to Vac-Loc™.CONCLUSION:
Vac-Loc™ and Tcast are valid options for immobilization with no clear superiority of either device. The marginal advantage of Tcast warrants further prospective studies.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sarcoma
/
Planejamento da Radioterapia Assistida por Computador
Tipo de estudo:
Observational_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article