Measurement of the sensitometric curves of Kodak EDR2 and X-Omat V films using Enhanced Dynamic Wedges and Dynamic Multileaf Collimators
✍ Scribed by Krzysztof Chełmiński; Joanna Rostkowska; Małgorzata Kania; Wojciech Bulski; Barbara Gwiazdowska
- Book ID
- 104441565
- Publisher
- Wielkopolskie Centrum Onkologii
- Year
- 2005
- Tongue
- Polish
- Weight
- 868 KB
- Volume
- 10
- Category
- Article
- ISSN
- 1507-1367
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✦ Synopsis
Background
Modern linear accelerators, used in oncological radiotherapy, are often equipped with a dynamic wedge option and dynamic multileaf collimators. For linacs having these options, measurements of absorbed dose distribution require complete movement of the jaw, or of the dynamic multileaf collimator, for each measurement point. In conformal radiotherapy, three or more beams, modifi ed by dynamic accessories, are combined to produce a summarized dose distribution.
Aim
This study is an investigation of the use of fi lm as a detector of dose distribution produced by a single beam, or by a pair of beams modifi ed by dynamic accessories, in phantoms.
Materials/Methods Measurements of the sensitometric curve of the recently introduced EDR2 (extended dose range) and extensively used X-Omat V radiographic fi lms were performed. Films were irradiated using a Clinac 2300 C/D VarianÔ accelerator, equipped with dMLC (dynamic multileaf collimator) and EDW (enhanced dynamic wedge) options. The recorded wedge dose distribution created by the EDW and by programmed dMLC movement were used to obtain response curves of the fi lms. Solid WaterÔ 457 blocks, manufactured by Gammex RMI, were used as phantoms, in which the fi lms were irradiated.
Results
Measurement and verifi cation of dose distributions created by beams modifi ed by dynamic accessories can be performed using both EDR2 and X-Omat V radiographic fi lms. The EDR2 low sensitivity fi lms are suitable for measurements of total dose distribution, as created by a number of dynamically modulated beams. High sensitivity X-Omat V fi lms are more suited to verifi cation of energy fl ow, or of the dose distribution generated by single fi elds, modifi ed by dynamic accessories.
Conclusions
The presented methods for the measurement of sensitometric curves may be applied in the routine calibration of fi lm dosimetry chains for IMRT plan verifi cation.