Abstract：Objective To compare the treatment planning in Helical Tomotherapy (HT) and conventional intensity modulated radiation treatment(IMRT) system in 2 different dosimetry distribution of nasopharyngeal carcinoma (NPC), and analyze the target area and the dose to organ at risk. Materials and Methods Chose 18 cases of NPC and transfer their positioning data information and the outline of target organs to Tomotherapy workstation and TPS Varian Eclipse TPS workstation for the design of IMRT, and the prescription dose which used on these 18 patients are the same, with 73.92Gy/33 for the gross tumor volume(GTVnx); 69.96 Gy/33F for the positive lymph nodes(GTVnd); 60.06Gy/33F for the high risk clinical target volume (CTV1 ); 50.96Gy/28F for the lower risk clinical target volume (CTV2 ). Compared the treatment planning of the 2 groups through conformation number (CN), homogeneity index (HI) of the target area, and maximum and average dose of the organs at risk (OARs) , and performed a paired t test on the datas of the two groups. Results The CN of PGTVnx, PTV1, PTV2 in HT groups were 0.910 ± 0.010, 0.855± 0.020, 0.871±0.021, and in conventional IMRTgroups were 0.867±0.025, 0.822±0.020, 0.811±0.012. The HI of PGTVnx, PTV1, PTV2 in HT groups were 1.049±0.009, 1.135±0.030, 1.034±0.011, and in conventional IMRT groups were 1.060±0.011, 1.222±0.023, 1.094±0.015. P< 0.005. Compared with the conventional intensity-modulated groups, in HT groups the CN and HI of target areas had improved with different degrees, the maximum and average dose to organs at risk were also decreased, average dose in parotid glands is about 4 Gy lower, V30, V35 were significantly lower than that in conventional IMRT, P< 0.005. Conclusion For NPC, compared with conventional IMRT technology, HT technique improves the dosimetry distribution, and helps target area to get better dose distribution and reduces the exposure dose to normal tissues at the same time.
杭霞瑜，刘海，李益坤，王晓萍，丁魏，张新良. 鼻咽癌螺旋断层放疗与常规调强放疗的剂量学分析[J]. 中国医疗设备, 2013, 28(12): 15-18.
HANG Xia-yu, LIU Hai, LI Yi-kun, WANG Xiao-ping, DING Wei, ZHANG Xin-liang. A Dosimetric Analysis between Helical Tomotherapy and Conventional IMRT for Nasopharyngeal Carcinoma. China Medical Devices, 2013, 28(12): 15-18.
Sheng K,Molloy JA,Larner JM,Read PW,et al.A dosimertic comparison of non-coplanar IMRT versus Helical Tomotherapy for nasal cavity and paranasal sinus cancer[J]. Radiother Oncol, 2007,82:174-8.
[9]
Fiorino C,DellOcal,Pierelli A,et al.Significant improvement in normal tissue sparing and target coverage for head and neck cancer by means of helical tomotherapy[J].Radiothe Oncol,2006,78:276-82
[10]
Wang X,Zhang X,Dong L,et al. Effectiveness of noncoplanar IMRT planning using a parallelized multiresolution beam angle optimization method for paranasal sinus carcinoma[J]. Radiat Oncol Biol Phys. 2005,63:594-601.
[11]
Fiorino C,Dell,Oca I,Pierelli A, et al. Simultaneous integrated boost(SIB) for nasopharynx cancer with helical tomotherapy[J]. Strahlentherapie und Onkologie ,2007,183:497-505.
[5]
Mackie TR,Homes T,Swerdloff S, et al. Tomotherapy:a new concept for the delivery of dynamic conformal radiotherapy[J]. Med Phys,1993,20(6):1709-1719.
[12]
Nill S, Tucking T,Munter MW, Oelfke U,et al. Intensity modulated radiation therapy with multileaf collimators of different leaf widths:a comparison of achievable dose distributions[J].Radiother Oncol, 2005,75:106-11.
[6]
Sheng K,Molloy JA,Read PW,et al.Intensity-modulated radiation therapy(IMRT) dosimetry of the head and neck:a comparison of treatment plans using linear accelerator-based IMRT and helical tomotherapy[J]. Radiat Oncol Boil Phys, 2006,65:917-23.
[7]
van Vulpen M,Field C,Raaijmakers CPJ,et al.Comparing step-and-shoot IMRT with dynamic helical tomotherapy IMRT plans for head-and-neck cancer[J].Radiat Oncol Biol Phys,2005,62:1535-9.
[8]
Sheng K,Molloy JA,Larner JM,Read PW,et al.A dosimertic comparison of non-coplanar IMRT versus Helical Tomotherapy for nasal cavity and paranasal sinus cancer[J]. Radiother Oncol, 2007,82:174-8.
[10]
Wang X,Zhang X,Dong L,et al. Effectiveness of noncoplanar IMRT planning using a parallelized multiresolution beam angle optimization method for paranasal sinus carcinoma[J]. Radiat Oncol Biol Phys. 2005,63:594-601.
[11]
Fiorino C,Dell,Oca I,Pierelli A, et al. Simultaneous integrated boost(SIB) for nasopharynx cancer with helical tomotherapy[J]. Strahlentherapie und Onkologie ,2007,183:497-505.
Wu C,Guo F,Purdy JA.Helical tomotherapy shielding calculation for an existing LINAC treatment room: sample calculation and cautions[J].Phys Med Biol,2006,51:N389-92.
[9]
Fiorino C,DellOcal,Pierelli A,et al.Significant improvement in normal tissue sparing and target coverage for head and neck cancer by means of helical tomotherapy[J].Radiothe Oncol,2006,78:276-82
[1]
殷蔚伯,余子豪,徐国镇,等.肿瘤放射治疗学[M].北京:中国协和医科大学出版社,2007.
[3]
van Asselen B,Dehnad H,Terhaard CH,et al.Segmental IMRT for oropharyngeal cancer in a clinical setting[J].Radiother Oncol,2003,69:259-66.
[12]
Nill S, Tucking T,Munter MW, Oelfke U,et al. Intensity modulated radiation therapy with multileaf collimators of different leaf widths:a comparison of achievable dose distributions[J].Radiother Oncol, 2005,75:106-11.
