Radiation Dosimetry Results for Nitinol: An Experimental Stud
Alaattin ÖZEN1,Kerem DURUER3,Helin İSMET4
1Department of Radiation Oncology, Üsküdar University Faculty of Medicine, İstanbul-Türkiye
2Comprehensive Cancer Center, Hisar Hospital Intercontinental, İstanbul-Türkiye
3Department of Radiation Oncology, Eskisehir Osmangazi University Faculty of Medicine, Eskisehir-Türkiye
4Eskişehir Technical University, Faculty of Architecture and Design, Eskisehir-Türkiye
DOI : 10.5505/tjo.2024.4242 OBJECTIVE
Shape-memory polymers (SMPs) are smart materials suitable for modifying size, shape, stiffness, and strain in response to different external stimuli. Nitinol, used in the medical field, has increased in recent years and is the most important example of SMPs. In this study, we aimed to make the dosimetric evaluation of Nitinol to test its usability in Brachytherapy treatment.

To achieve the aim of the study, we designed a tandem to be made of polyamide 12 for the straight part (4 and 6 centimeters on both sides) and Nitinol for the angled part (4 centimeters). Afterward, we placed the produced tandem into the bolus and measured the dose using different dosimetry methods such as the treatment planning system (TPS), GafChromic film dosimetry, and MOSFET dosimetry. Three different measurements were made with the same irradiation dose for each measurement method, and the average results were recorded.

The Euclidean distance between the source and the measuring point was 34.0 millimeters for the Polyamide 12 part, and 32.8 millimeters for the Nitinol part. The calculated irradiation time was 284.9 seconds for the Polyamide 12 part and 268.2 seconds for the Nitinol part. Considering the irradiation times and source distances, the calculated difference between Nitinol and Polyamide 12 was 1.15%. This difference was 1.0%, 1.87%, and 2.08% for TG43, MOSFET, and GafChromic film dosimetry, respectively.

In conclusion, Nitinol did not have a negative effect on the dose distribution. However, these results should be supported by further studies including other dosimetry measurements. Keywords : Brachytherapy; gafchromic film dosimetry; MOSFET dosimetry; nitinol