Journal of Medical Physics
 Home | Search | Ahead of print | Current Issue | Archives | Instructions | Subscription | Login  The official journal of Association of Medical Physicists of India      
 Users online: 458  Home  EMail this page Print this page Decrease font size Default font size Increase font size 
ORIGINAL ARTICLE
Year : 2015  |  Volume : 40  |  Issue : 2  |  Page : 61-67

Small fields measurements with radiochromic films


1 Hospital Universitario Virgen de la Arrixaca, Carretera Madrid-Cartagena, Murcia, Spain
2 Servicio de Proteccion Radiologica y Fisica Medica, Hospital Sant Joan de Reus, Reus, Tarragona, Spain

Correspondence Address:
Prof. Antonio Gonzalez-Lopez
Hospital Universitario Virgen de la Arrixaca, Carretera Madrid-Cartagena, 30120 El Palmar, Murcia
Spain
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-6203.158667

Rights and Permissions

The small fields in radiotherapy are widely used due to the development of techniques such as intensity-modulated radiotherapy and stereotactic radio surgery. The measurement of the dose distributions for small fields is a challenge. A perfect dosimeter should be independent of the radiation energy and the dose rate and should have a negligible volume effect. The radiochromic (RC) film characteristics fit well to these requirements. However, the response of RC films and their digitizing processes present a significant spatial inhomogeneity problem. The present work uses a method for two-dimensional (2D) measurement with RC films based on the reduction of the spatial inhomogeneity of both the film and the film digitizing process. By means of registering and averaging several measurements of the same field, the inhomogeneities are mostly canceled. Measurements of output factors (OFs), dose profiles (in-plane and cross-plane), and 2D dose distributions are presented. The field sizes investigated are 0.5 × 0.5 cm 2 , 0.7 × 0.7 cm 2 , 1 × 1 cm 2 , 2 × 2 cm 2 , 3 × 3 cm 2 , 6 × 6 cm 2 , and 10 × 10 cm 2 for 6 and 15 MV photon beams. The OFs measured with the RC film are compared with the measurements carried out with a PinPoint ionization chamber (IC) and a Semiflex IC, while the measured transversal dose profiles were compared with Monte Carlo simulations. The results obtained for the OFs measurements show a good agreement with the values obtained from RC films and the PinPoint and Semiflex chambers when the field size is greater or equal than 2 × 2 cm 2 . These agreements give confidence on the accuracy of the method as well as on the results obtained for smaller fields. Also, good agreement was found between the measured profiles and the Monte Carlo calculated profiles for the field size of 1 × 1 cm 2 . We expect, therefore, that the presented method can be used to perform accurate measurements of small fields.


[FULL TEXT] [PDF]*
Print this article     Email this article
 Next article
 Previous article
 Table of Contents

 Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
 Citation Manager
 Access Statistics
 Reader Comments
 Email Alert *
 Add to My List *
 * Requires registration (Free)
 

 Article Access Statistics
    Viewed2245    
    Printed60    
    Emailed0    
    PDF Downloaded222    
    Comments [Add]    

Recommend this journal