On the impact of improved dosimetric accuracy on head and neck high dose rate brachytherapy

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• 作者：Vasiliki Peppa^a ; Eleftherios Pappas^a ; Tibor Major^b ; Zoltá ; n Taká ; csi-Nagy^b ; Evaggelos Pantelis^a ; Panagiotis Papagiannis^a ; ^{ppapagi@med.uoa.gr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Brachytherapy ; High dose rate ; Head and neck ; Dosimetry ; Treatment planning
• 刊名：Radiotherapy and Oncology
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：120
• 期：1
• 页码：92-97
• 全文大小：930 K

文摘

To study the effect of finite patient dimensions and tissue heterogeneities in head and neck high dose rate brachytherapy.

Methods and materials

The current practice of TG-43 dosimetry was compared to patient specific dosimetry obtained using Monte Carlo simulation for a sample of 22 patient plans. The dose distributions were compared in terms of percentage dose differences as well as differences in dose volume histogram and radiobiological indices for the target and organs at risk (mandible, parotids, skin, and spinal cord).

Results

Noticeable percentage differences exist between TG-43 and patient specific dosimetry, mainly at low dose points. Expressed as fractions of the planning aim dose, percentage differences are within 2% with a general TG-43 overestimation except for the spine. These differences are consistent resulting in statistically significant differences of dose volume histogram and radiobiology indices. Absolute differences of these indices are however small to warrant clinical importance in terms of tumor control or complication probabilities.

Conclusions

The introduction of dosimetry methods characterized by improved accuracy is a valuable advancement. It does not appear however to influence dose prescription or call for amendment of clinical recommendations for the mobile tongue, base of tongue, and floor of mouth patient cohort of this study.