915MHz microwave ablation with high output power in in vivo porcine spleens

Gao, Yongyan; Wang, Yang; Duan, Yaqi; Li, Chunling; Sun, Yuanyuan; Zhang, Dakun; Lu, Tong; Liang, Ping

doi:10.1016/j.ejrad.2009.03.009

« Previous Next »European Journal of Radiology
Volume 75, Issue 1 , Pages 87-90, July 2010

915MHz microwave ablation with high output power in in vivo porcine spleens

Yongyan Gao
- Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Rd., Beijing 100853, China
- Department of Special Diagnosis, The General Hospital of Chinese People's Armed Police Forces, 69 Yongding Rd., Beijing 100039, China
- Tel.: +86 010 66939530; fax: +86 010 88210006.
Yang Wang
- Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Rd., Beijing 100853, China
- Tel.: +86 010 66939530; fax: +86 010 88210006.
Yaqi Duan
- Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Rd., Beijing 100853, China
- Tel.: +86 010 66939530; fax: +86 010 88210006.
Chunling Li
- Department of Special Diagnosis, The General Hospital of Chinese People's Armed Police Forces, 69 Yongding Rd., Beijing 100039, China
- Tel.: +86 010 88276772; fax: +86 010 88276114.
Yuanyuan Sun
- Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Rd., Beijing 100853, China
- Tel.: +86 010 66939530; fax: +86 010 88210006.
Dakun Zhang
- Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Rd., Beijing 100853, China
- Tel.: +86 010 66939530; fax: +86 010 88210006.
Tong Lu
- Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Rd., Beijing 100853, China
- Tel.: +86 010 66939530; fax: +86 010 88210006.
Ping Liang
- Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Rd., Beijing 100853, China
- Corresponding author. Tel.: +86 010 66939530; fax: +86 010 88210006.

Received 29 October 2008; received in revised form 18 February 2009; accepted 6 March 2009.

Abstract

Objective

The purpose of this study was to evaluate the efficacy of 915MHz microwave (MW) ablation with high output power in in vivo porcine spleens.

Materials and methods

MW ablations were performed in 9 porcine spleens with an internally cooled 915MHz antenna. Thermocouples were placed at 5, 10, 15, 20mm away from the antenna to measure temperatures in real-time during MW emission. The energy was applied for 10min at high output power of 60W, 70W or 80W. Gross specimens were sectioned and measured to determine ablation size. Representative areas were examined by light microscopy and electron microscopy. Coagulation sizes and temperatures were compared among the three power groups.

Results

Hematoxylin-eosin staining showed irreversible necrosis in the splenic coagulation area after MW ablation. As the power was increased, long-axis diameter enlarged significantly (p<.05). Short-axis diameter also tended to increase, but there were no statistical difference (p>.05). The coagulation size of long-axis and short-axis diameter with 80W in vivo spleen ablation was 6.43±0.52 and 4.95±0.30cm, respectively. With the increase of output power, maximum temperatures at 5, 10, 15, 20mm from the antenna were increased accordingly (p<.05). The maximum temperature with 80W at 5 and 20mm from the antenna reached 146.17±6.65 and 72.38±4.23°C respectively.

Conclusion

With internally cooled antenna and high output power, 915MHz MW ablation in the spleen could produce irreversible tissue necrosis of clinical significance. MW ablation may be used as a promising minimally invasive method for the treatment of splenic diseases.

Keywords: Microwave, Ablation, Thermal therapy, Spleen