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Objective:To preliminarily observe the feasibility of different immobilization techniques for total skin irradiation (TSI) using helical tomotherapy.Methods:Three eczema scrophuloderma patients treated with TSI in Sun Yat-sen University Cancer Center were immobilized with low-temperature thermoplastic in a prone position, diving suit combined with negative pressure vacuum bag in a supine position, low-temperature thermoplastic combined with vacuum bag in a supine position, respectively. Different immobilization effects were observed. The conformity index (CI) of the target area, heterogeneity index (HI) of the target area, and the mean dose (D mean) of the target area were calculated. Results:Three immobilization methods could achieve satisfactory immobilization effects, and all the dosimetric parameters of radiation treatment plans met the clinical requirements. The average set-up errors in the left and right, head and foot, and abdomen and back directions of three patients were (0.26±3.40) mm, (-2.63±4.63) mm and (6.13±4.86) mm, respectively. The CI, HI andD mean were0.56±0.09, 1.186±0.059 and (2586.56±63.28) cGy. Conclusions:Low-temperature thermoplastic or diving suits can be combined with vacuum bags for immobilization in TSI. The epidermal dose can be increased with bolus through the dose-building effect, which can provide a safe and reliable method for TSI in helical tomotherapy.
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Objective:To standardize the naming of organ at risk (OAR) and target area during cervical cancer radiotherapy based on AAPM TG-263.Methods:After self-programming of Matlab software to implement the reading and resolution of radiotherapy structure files, the naming of each substructure was automatically output, recorded and restored. After naming all substructures, the structure names were classified by keywords. According to TG-263, a standard naming conversion table of OAR and target area was developed, and the classified structure names were standardized through procedures. Finally, the standardized named radiotherapy structure files were output and imported into the treatment planning system (TPS).Results:The radiation structure of 144 patients with cervical cancer was successfully transformed and displayed correctly in TPS. Before the transformation, the naming of OAR and target area lacked of uniform norms and standards, and the naming of the same structure significantly differed. After the transformation, 43 naming methods of OAR and 74 naming methods of the target area were unified into 20 and 8 naming methods, which were more convenient for staff understanding and communication.Conclusion:The standardization of cervical cancer radiotherapy structure naming can reduce the inconsistency of naming and provide reference for the standardized naming of pelvic tumors.
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Objective To propose a new suggestion for the clinical downstaging of nasopharyngeal carcinoma (NPC) in the era of intensity-modulated radiotherapy (IMRT) without changing the current T,N,and M staging system.Methods We reviewed the records of 536 NPC patients treated in Sun Yat-Sen University Cancer Center from January 2002 to December 2006.The Kaplan-Meier method was used to calculate the disease-specific survival (DSS) rate,and the log-rank test was used for survival difference analysis.The Cox regression model was used to calculate the hazard ratio (HR) of each subset.ResultsAccording to the 7th edition of UICC/AJCC staging system,the 5-year DSS rates of stage Ⅰ-Ⅲ patients (except T3N2M0) were all more than 85%(P>0.05),those of stage ⅣA and ⅣB patients were 71.8% and 46.2%,respectively (P=0.171),and that of stage ⅠVC patients was only 24.0%.In stage Ⅲ,the 5-year DSS rate of non-T3N2M0 patients (91.5%) was significantly higher than that of T3N2M0 patients (78.6%)(P=0.042),but there was no significant difference in DSS between T3N2M0 patients and stage ⅣA and ⅣB patients.Based on the above results,new stage Ⅰ included T1-3N0-1M0 and T1-2N2M0,new stage Ⅱ included T3N2M0,T4N0-2M0,and TxN3M0,and new stage Ⅲ included TxNxM1.The 5-year DSS rates of new stage Ⅰ,Ⅱ,and Ⅲ patients were 93.3%,72.7%,and 24.0%,respectively (P=0.000).Compared with new stage Ⅰ patients,new stage Ⅱ and Ⅲ patients had HRs of 4.01 and 16.76,respectively,for 5-year DSS.Conclusions In the era of IMRT,the new clinical staging system (stages Ⅰ,Ⅱ,and Ⅲ) helps with prognostic evaluation and clinical treatment.