A methodology for dosimetry audit of rotational radiotherapy using a commercial detector array

详细信息    查看全文

• 作者：Mohammad Hussein ; Yatman Tsang ; Russell A.S. Thomas ; Clare Gouldstone ; David Maughan ; Julia A.D. Snaith ; Steven C. Bolton ; Andrew Nisbet ; Catharine H. Clark
• 关键词：Detector arrays ; 2D-Array ; Dosimetry audit ; Rotational radiotherapy ; VMAT ; Tomotherapy
• 刊名：Radiotherapy and Oncology
• 出版年：2013
• 出版时间：July, 2013
• 年：2013
• 卷：108
• 期：1
• 页码：78-85
• 全文大小：1163 K

文摘

Purpose

To develop a methodology for the use of a commercial detector array in dosimetry audits of rotational radiotherapy.

Materials and methods

The methodology was developed as part of the development of a national audit of rotational radiotherapy. Ten cancer centres were asked to create a rotational radiotherapy treatment plan for a three-dimensional treatment-planning-system (3DTPS) test and audited. Phantom measurements using a commercial 2D ionisation chamber (IC) array were compared with measurements using 0.125 cm³ IC, Gafchromic film and alanine pellets in the same plane. Relative and absolute gamma index (¦Ã) comparisons were made for Gafchromic film and 2D-Array planes, respectively.

Results

Comparisons between individual detectors within the 2D-Array against the corresponding IC and alanine measurement showed a statistically significant concordance correlation coefficient (both ¦Ñ_c > 0.998, p < 0.001) with mean difference of ?1.1 ¡À 1.1 % and ?0.8 ¡À 1.1 % , respectively, in a high dose PTV. In the ¦Ã comparison between the 2D-Array and film it was that the 2D-Array was more likely to fail planes where there was a dose discrepancy due to the absolute analysis performed.

Conclusions

It has been found that using a commercial detector array for a dosimetry audit of rotational radiotherapy is suitable in place of standard systems of dosimetry.