Objective To determine the maximum-tolerated dose (MTD) and dose-limiting toxicities (DLTs) of capecitabine during postoperative concurrent capecitabine and intensity-modulated radiotherapy (IMRT) for locally advanced gastric cancer. Methods The patients, who had T_xN (+) M₀ gastroesophageal or gastric adenocarcinoma after radical surgery with negative margins (R₀) or non-radical surgery with microscopically positive margins (R₁) or macroscopically positive margins (R₂), were included in the study. A total of 18 patients (R₀ 12;R₁ 2;R₂ 4) were recruited. IMRT (45 Gy at 1.8 Gy/fraction) was delivered to the tumor bed (T_4b only), anastomosis site, duodenal stump, and regional lymph nodes days per week for 5 weeks. Patients with R₁ or R₂ resection received additional radiation (10.8 Gy/6 fractions) to the microscopically or macroscopically positive margins. During IMRT, capecitabine was orally administered twice daily at a dose of 625 mg/m²(level I, n=6), 700 mg/m²(level Ⅱ, n=6), 800 mg/m²(level Ⅲ, n=6), 900 mg/m²(level IV, n=0), and 1000 mg/m²(level V, n=0). DLT was defined as grade 3 or 4 hematologic and non-hematologic toxicities. Results Grade 1—3 leukopenia (89%), anorexia (83%), and nausea (83%) were the most common toxicities. Grade 3 anorexia/nausea and grade 4 vomiting occurred in one patient at dose level I. Grade 3 anorexia and nausea occurred in one patient at dose level Ⅱ. One patient at dose level Ⅲ developed grade 4 neutropenia, while another patient at dose level Ⅲ developed grade 3 radiation esophagitis. Conclusions During postoperative concurrent capecitabine and IMRT for locally advanced gastric cancer, the MTD of capecitabine is 800 mg/m² twice daily, and the DLTs are nausea, vomiting, anorexia, neutropenia, and radiation esophagitis.

Objective To investigate the changes in postmastectomy radiotherapy (PMRT) targets among breast cancer patients in China. Methods A multi-center retrospective epidemiological study was undertaken. Breast cancer patients who had received PMRT from 1999 to 2008 were randomly selected from seven hospitals in China, and the information on radiation targets, including the chest wall (CW), supraclavicular and infraclavicular regions (SCR/ICR), axilla, and internal mammary chain (IMC) was collected and analyzed. The Cochran-Armitage trend test and chi-square test were performed using SAS software to analyze the variation of PMRT targets over time, the differences in PMRT targets between hospitals, and the relationship between PMRT targets and clinicopathologic characteristics. Results Of 661 included patients, 596(90.2%), 606(91.5%), 196(29.6%), and 297(44.9%) had received PMRT to the CW, SCR/ICR, axilla, and IMC, respectively. From 1999 to 2008, there were an increase in use of PMRT to the CW (P=0.000) and decreases in use of PMRT to the axilla (P=0.027) and IMC (P=0.000). There were significant differences in use of PMRT to the CW (P=0.008), axilla (P=0.000), IMC (P=0.000),and SCR/ICR (P=0.000) between hospitals, but there were no significant differences in use of PMRT to the SCR/ICR from 1999 to 2008(P=0.597). Use of PMRT to the axilla was associated with positive axillary nodes (P=0.007) and an axillary nodal ratio of 20% or more (P=0.007). Use of PMRT to the IMC was more frequent in patients with tumor located in the inner quadrant (P=0.015). Conclusions From 1999 to 2008, PMRT targets among breast cancer patients varied greatly over time and between different hospitals in China;most patients received PMRT to the CW and SCR/ICR, and use of PMRT to the axilla and IMC decreased significantly.

Objective To investigate the differences in clinical features and prognosis between patients with stage Ⅰ_E—Ⅱ_E nasal cavity natural killer (NK)/T-cell lymphoma (NC-NKTL) and Waldeyer′s ring NK/T-cell lymphoma (WR-NKTL). Methods A retrospective analysis was performed on 273 patients with NK/T lymphoma who were initially treated in our hospital from January 1991 to December 2011. Of these patients, 184 had Ann Arbor stage Ⅰ_E disease, and 89 had stage Ⅱ_E disease;209 had NC-NKTL, and 64 had WR-NKTL. A total of 258 patients (94.5%) were first treated with chemotherapy. The majority of patients received CHOP or CHOP-like chemotherapy. The median dose of radiotherapy was 54 Gy. Results Compared with NC-NKTL patients, WR-NKTL patients had significantly higher percentages of individuals in stage Ⅱ_E and individuals with B symptoms (P<0.05 for both). The overall response rates of the two groups after treatment were similar (88.7% vs 87.9%, P=0.869). The follow-up rate was 96.3%. 196 patients were followed up for at least 5 years. The 5-year overall survival (OS) and progression-free survival (PFS) were 52.6% and 41.4%, respectively. The 5-year OS of NC-NKTL patients was nonsignificantly higher than that of WR-NKTL patients (57.0% vs 39.0%, P=0.062), while the 5-year PFS of NC-NKTL patients was significantly higher than that of WR-NKTL patients (46.7% vs 25.8%, P=0.019). Conclusions Patients with early-stage WR-NKTL are more prone to systemic symptoms and cervical lymph node metastasis and have poorer prognosis, as compared with patients with early-stage NC-NKTL, so radiotherapy and prophylactic irradiation should be considered in early stage.

Objective To investigate the effects of computed tomography (CT) slice thickness, lumpectomy cavity (LC) volume, cavity visualization score (CVS), and number of metal clips on the interobserver and intraobserver variability in the delineation of LC after breast-conserving surgery based on four-dimensional (4D) CT. Methods Thirty-five patients who had underwent breast-conserving surgery and had at least 5 metal clips placed in the LCs underwent 4DCT scans. For each patient, LC was delineated on the CT images in the T₅₀(end-exhalation) phase. The patients were stratified according to LC volume, CVS, CT slice thickness, and number of metal clips. Among different patient groups, interobserver and intraobserver variability in LC (Δ_inter and Δ_intra) and the dice similarity coefficients (DSCs) between LCs (DSC_inter and DSC_intra) were evaluated and compared. Results LC volume, CVS, number of metal clips, and 4DCT slice thickness were not significantly correlated with Δ_intra and DSC_intra (P=0.628,0.842,0.080). There were no significant differences in Δ_inter and DSC_inter between the patient groups with 4DCT slice thickness of 2, 3, and 5 mm (P=0.211 and 0.727), and there was no correlation between 4DCT slice thickness and Δ_inter and DSC_inter (P=0.414,0.594). LC volume was negatively correlated with Δ_inter (P=0.024);compared with those with LC volumes smaller than the mean value, the patients with LC volumes not smaller than the mean value had a significantly higher DSC_inter (P=0.025) and a significantly lower Δ_inter (P=0.009). The patient group with a CVS of 3－5 had a significantly higher DSC_inter than that with a CVS of 1－2(P=0.004), and CVS was positively correlated with DSC_inter (P=0.007). There were no significant differences in Δ_inter and DSC_inter between the patient groups with 7－9 and 5－6 metal clips (P=0.159,0.825). Conclusions For the breast cancer patients who have at least 5 metal clips placed at the boundary of LC after breast-conserving surgery, LC volume and CVS are still the main influential factors for variability in LC delineation. More metal clips in addition to 5－6 ones are not helpful for LC delineation.

Objective To conduct a comparative study of the volume and location of the lumpectomy cavity delineated by metal clips and/or seroma on four-dimensional computed tomography (4DCT) for external-beam partial breast irradiation. Methods On 10 respiratory phases of 4DCT images with 15 breast cancer patients, gross tumor volumes (GTV_S) were delineated based on the metal clips at the boundaries of surgical cavity, seroma, and metal clips plus seroma to obtain GTV_C, GTV_S, and GTV_C+S, respectively. The volumes of GTV_C, GTV_S, and GTV_C+S were measured, and the conformity index (CI), degree of inclusion (DI), and centroid distance between each two GTV_S were calculated. One-way analysis of variance was used to compare volume and CI between GTV_C, GTV_S, and GTV_C+S;the paired t-test was used for comparison of DI;the Pearson correlation test was used to investigate the relationship of CI and DI with centroid distance. Results The volumes of GTV_C, GTV_S, and GTV_C+S were 23.15±13.34 cm³, 19.27±17.53 cm³, and 24.60±16.72 cm³, respectively (P=0.000). The CIs of GTV_C vs GTV_S, GTV_C vs GTV_C+S, and GTV_S vs GTV_C+S were 0.36±0.14, 0.60±0.14, and 0.53±0.20, respectively (P=0.000). The DI of GTV_S in GTV_C was significantly higher than that of GTV_C in GTV_S (0.67±0.21 vs 0.48±0.20, P=0.000);the DI of GTV_C in GTV_C+S was significantly higher than that of GTV_C+S in GTV_C (0.82±0.11 vs 0.71±0.19, P=0.000);the DI of GTV_S in GTV_C+S was significantly higher than that of GTV_C+S in GTV_S (0.91±0.14 vs 0.52±0.22;P=0.000). The DIs and CIs of GTV_C vs GTV_S, GTV_C vs GTV_C+S, and GTV_S vs GTV_C+Swere negatively correlated with their centroid distances (P=0.000 for all comparisons). Conclusions There are volume differences and spatial mismatches between the GTV_S delineated based on metal clips, seroma, and metal clips plus seroma.

Objective To investigate the efficacy and safety of thoracic radiotherapy (TR) and prophylactic cranial irradiation (PCI) in patients with extensive small cell lung cancer (SCLC) who show response to chemotherapy. Methods From July 2010 to March 2012, 30 patients with a pathological or cytological diagnosis of extensive SCLC who showed response to 4—6 cycles of chemotherapy with carboplatin plus etoposide or chemotherapy with cisplatin plus etoposide were included in the study. The median age of patients was 57 years (range, 40—71 years). All the patients received TR (50—60 Gy) and PCI (25 Gy). The short-term efficacy was assessed by RECIST 1.1, and the toxicities were evaluated according to CTCAE 3.0 and RTOG radiation morbidity scoring criteria. Results Twenty-nine of the 30 patients completed the TR and PCI. Of these patients, 13% showed complete remission, 27% showed partial remission, and 60% showed stable disease, and the disease control rate was 100%. Progression was seen in 16 patients after effective treatment, including 1 patients with locoregional failure (LRF) alone and 15 patients with distant failure (DF)(9 patients with DF alone and 6 patients with locoregional and distant metastases, 4 patients with brain metastasis). The follow-up rate was 100%. The 1-year LRF rate and DF rate were 24% and 51%, respectively. The 1-year overall survival rate and disease-free survival rate were 71% and 37%, respectively. The acute toxicities included grade ≥2 hematological toxicity and grade ≥2 radiation esophagitis, which occurred in 33% and 13% of all patients. Conclusions TR and PCI have good short-term efficacy and safety in extensive SCLC patients with response to chemotherapy and can reduceDOI:10.3760/cma.j.issn.1004-4221.2013.05.007基金项目:北京希望马拉松专项基金(N2010-8)作者单位:100021 北京协和医学院中国医学科学院肿瘤医院肿瘤研究所放疗科(张文珏、周宗玫、陈东福、梁军、冯勤付、张红星、王小震、惠周光、肖泽芬、吕纪马、王绿化),内科(李峻岭)通信作者:周宗玫,Email:zhouzongmei2013@163.combrain metastases and local recurrence. However, further study is needed with a larger sample.

Objective To analyze the clinical features, prognostic factors, and role of radiotherapy in combined small cell lung cancer (C-SCLC). Methods A retrospective analysis was performed in 44 patients who were histologically diagnosed with C-SCLC from January 2005 to December 2011. The Kaplan-Meier method was used to estimate survival, and the log-rank test was used for univariate prognostic analysis. Results The follow-up was 100%. Fourteen patients were followed up for at least 3 years, and 9 patients for at least 5 years. The 1-, 3-, and 5-year overall survival (OS) rates were 69%, 47%, and 33%, respectively, and the 1-, 3-, and 5-year progression-free survival rates were 53%, 44%, and 32%, respectively. The univariate analysis showed that Karnofsky performance scale (KPS) score of<80(P=0.006), presence of non-squamous cell carcinoma (P=0.006), tumor diameter of>3 cm (P=0.049), and positive surgical margin (P=0.001) were associated with poorer OS. Radiotherapy significantly improved the OS in patients with stage Ⅲ_A/Ⅲ_B disease (P=0.032), positive lymph nodes (P=0.006), or over 4 positive lymph nodes after surgery (P=0.025), and it nonsignificantly improved the OS in patients with T₃—T₄ disease (P=0.179). Conclusions C-SCLC is mostly in limited stage, and multimodality therapy is recommended. KPS score of<80, presence of non-squamous cell carcinoma, tumor diameter of>3 cm, and positive surgical margin are poor prognostic factors. Radiotherapy can improve the OS in patients with stage Ⅲ_A/Ⅲ_B disease, positive lymph nodes, or over 4 positive lymph nodes after surgery.

Objective To investigate the role of three-dimensional (3D) radiotherapy to the thoracic primary tumor in non-small cell lung cancer (NSCLC) patients with bone metastases during chemotherapy with concurrent 3D radiotherapy. Methods From 2003 to 2010, the clinical data of 95 stage Ⅳ NSCLC patients with bone metastases were collected. All patients received 3D radiotherapy to the thoracic primary tumor and at least 2 cycles of chemotherapy. Of the 95 patients, 47 had only bone metastases, and 48 had metastases to bones and other organs. The Kaplan-Meier method was used to calculate overall survival (OS) rates. The log-rank test was used for survival difference analysis and univariate prognostic analysis. The Cox regression model was used for multivariate prognostic analysis. Results The follow-up rate was 95%. The 1-, 2-, and 3-year OS rates were 44%, 17%, and 9%, respectively. The univariate analysis showed that radiation dose to the planning target volume (PTV) of primary tumor of ≥63 Gy, response to treatment of primary tumor, and at least 4 cycles of chemotherapy were favorable prognostic factors for OS in all patients (P=0.001, 0.037, and 0.009). Radiation dose to the PTV of primary tumor of ≥63 Gy remained the favorable prognostic factor for OS in patients with only bone metastases and those with metastases to bones and other organs (P=0.045 and 0.012). Among patients with only bone metastases, those with T₁+T₂ primary tumors had longer OS than those with T₃+T₄ primary tumors (P=0.048). The multivariate analysis showed that radiation dose to the PTV of primary tumor of ≥63 Gy and metastases to bones only were independent favorable prognostic factors for OS in all patients (P=0.036 and 0.035). Conclusions For NSCLC patients with bone metastases, 3D radiotherapy to the thoracic primary tumor and its dose play an important role in improving OS during chemotherapy with concurrent 3D radiotherapy.

Objective To analyze the long-term outcome of nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT) with reduced clinical target volume (CTV)and to provide a basis for the application of reduced-volume IMRT in the treatment of NPC. MethodsBetween November 2003 and April 2007, 413 patients with NPC were treated with IMRT according our institutional protocol. The median age was 45 years;the patients included 311 males and 102 females. Of all patients, 3(0.7%) had stage Ⅰ NPC, 66(16%) had stage Ⅱ NPC, 235(56.9%) had stage Ⅲ NPC, 78(18.9%) had stage Ⅳ_a NPC, and 31(7.5%) had stage Ⅳ_b NPC, according to the 6^th edition of AJCC staging system. IMRT was delivered as follows:GTV 66.00—69.75 Gy/30—33 f;CTV-1 60.00—66.65 Gy/30—33 f;CTV-2/CTV-N 54.0—55.8 Gy/30—33 f. A total of 336 patients received cisplatin-based chemotherapy in addition to IMRT. Results The follow-up rate was 100%. With a median follow-up of 72 months, the 5-year overall survival (OS), local control, loco-regional recurrence-free survival, distant metastasis-free survival (DMFS), and disease-free survival rates were 80%, 93%, 96%, 81%, and 75%, respectively. The multivariate analysis revealed that T stage, N stage, and age were independent prognostic factors for OS (P=0.001,0.001,0.002);T stage and N stage were independent prognostic factors for DMFS (P=0.000,0.001). Among patients with stage Ⅲ and IV NPC, the 5-year OS rate was nonsignificantly higher in those treated with induction chemotherapy than in those not treated with induction chemotherapy (78% vs. 68%, P=0.053), but the 5-year DMFS rate was significantly lower in those treated with adjuvant chemotherapy than in those not treated with adjuvant chemotherapy (65% vs. 83%, P=0.003). Conclusions IMRT with reduced CTV is safe and reliable and can lead to a good long-term outcome in patients with NPC.

Objective To evaluate the treatment outcome and prognostic factors in patients with grade Ⅲ/IV glioma following postoperative chemoradiotherapy. Methods A retrospective analysis was performed on the medical records of 119 patients with grade Ⅲ/IV glioma who received treatment in our hospital from January 2007 to April 2012. Of the 119 patients, 49 received radiotherapy alone, 21 received radiotherapy combined with nitrosoureas, and 49 received radiotherapy combined with temozolomide. The Kaplan-Meier method was used to calculate overall survival (OS) rates and recurrence rates. The Cox regression model was used for multivariate prognostic analysis. Results The follow-up rate was 94.1%. Fifty-three patients were followed up for at least 1 year, and 10 for at least 2 years. The overall recurrence rate was 69.7%. The 1-and 2-year OS rates were 44.5% and 8.4%, respectively. The multivariate analysis showed that age, presence or absence of seizures before surgery, extent of tumor resection, and radiotherapy plus concurrent and adjuvant temozolomide were the main prognostic factors for tumor recurrence (P=0.002, 0.005, 0.000, and 0.000). The above factors and the pathological grade of tumor were the independent prognostic factors for patients′ survival (P=0.006, 0.010, 0.000, 0.000, and 0.001). Conclusions Postoperative radiotherapy plus concurrent and adjuvant temozolomide produce a good clinical effect in patients with grade Ⅲ/IV glioma. Age of<60 years, no seizures before surgery, total tumor resection, and pathological grade Ⅲ of tumor are the favorable prognostic factors for the long-term survival in patients with malignant glioma.

Objective To compare the errors of final isocenter marking method and reference pointmarking method for CT simulation positioning in intensity-modulated radiotherapy (IMRT). MethodsFrom 2009 to 2012, 327 patients with head and neck cancer for IMRT underwent CT simulation positioning using the Philips Brilliance CT Big Bore scanner and Philips Tumor LOC workstation and were divided into final isocenter marking group (n=208) and reference point marking group (n=119) according to positioning methods. Target volume delineation and treatment plan design were performed on the Varian Eclipse treatment planning system (TPS). Before treatment, kilovoltage cone-beam CT scans and registration were performed with the Varian EX on-board imager system to obtain beam position errors in the right-left (RL), superior-inferior (SI), and anterior-posterior (AP) directions, and then comparisons of errors between the two groups were made by independent-samples t test. Finally, the TPS was used to measure the changes in the doses to the organs at risk after moving isocenters in the RL, SI, and AP directions among 5 patients with nasopharyngeal carcinoma. Results The mean beam position errors in the three directions were less in the final isocenter marking group than in the reference point marking group (P=0.02,0.01,0.03). After moving isocenters in the three directions, the target dose was reduced and the dose to the normal tissue around the target tumor was increased significantly. The error in the AP direction had the maximum influence on the spinal cord and brainstem. Conclusions Final isocenter marking method leads to less beam position error than reference point marking method in CT simulation positioning. Small isocenter motion can cause large changes in the doses to the organs at risk.

Objective To analyze the difference of prescription dose between ICRU report 83 and Chinese recommendation in the nasopharyngeal carcinoma (NPC) for intensity modulated radiation therapy (IMRT). Methods Eighty-four NPC were treated using IMRT technology from Jan 1, 2010 to Apr 1, 2012. All dose volume histogram of the 84 IMRT plan were analyzed retrospectively. The target volumes of planning gross tumor volume of nasopharynx (PGTV_nx) or planning clinical target volume and high risk lymphatic drainage (PCTV₁) and doses of D₁₀₀,D₉₈,D₉₅,D₅₀,D₂ and D₀ were recorded. The mean, standard error, medial, range, coefficient of variation (CV) of PGTV_nx,PCTV₁,and D₁₀₀,D₉₈,D₉₅,D₅₀,D₂ and D₀ were calculated, respectively. The homogeneity index (HI) and deviation between D₉₅ and D₅₀ of PGTV_nx and PCTV₁ were calculated, respectively. The differentiation of grouping results were analyzed with grouped t-test method. Results The HI of PGTV_nx and PCTV₁ were 0.118±0.045 and 0.272±0.037, respectively. It is the bigger target volume, the worse HI;and the advanced T stage, the worse HI. Either PGTV_nx or PCTV₁, D₉₅ were less than D₅₀. The average deviation was －5.15% and －10.97%, and the actual difference value was (382±180) cGy (P=0.000) and (741±140) cGy (P=0.000).Conclusions D₅₀, which is the recommendation prescription dose of PTV in ICRU report 83, could evaluate accurately the IMRT plan with combining D₉₈ and D₂. When D₅₀ is used to instand of D₉₅, the prescription dose of PGTV_nx and PCTV₁ should increase 5% and 11%, respectively.

Objective To study the set-up accuracy in radiotherapy of thoracic neoplasms by improving the body immobilization method. Methods Fifty patients with thoracic neoplasms were randomly divided into conventional group (without electrode paste) and improved group (with electrode paste). Using simulator for position calibration and center field digital image reconstruction from treatment planning system.Then compare the set-up accuracy of two groups with different body methods by grouped t-test. ResultsSet-up error in the left-right, superior-inferior, anterior-posterior direction were 2.5±1.5 and 2.4±1.4(P=0.010),4.4±2.0 and 2.2±1.2(P=0.000),2.2±1.3 and 2.1±1.0(P=0.100) in conventional group and improved group,respectively. Conclusions The improved body immobilization method improves setup accuracy in radiotherapy for thoracic neoplasms which also will be effective for clinical treatment.

Objective To explore the necessity and feasibility of the real-time treatment planning optimization by CT guided with ¹²⁵I seed implantation brachytherapy treatment to thoracic malignancies. Methods To retrospectively analyze the data of 31 inpatients (from October 2010 to June 2012) with thoracic malignancie by CT guidance ¹²⁵I brachytherapy. The real-time planning optimization were applicated to 13 cases (group A), 18 patients undergoing experience particles implantation interval 1 cm (group B), all the patients were prescribed dose 110 Gy and post-planning verified after surgery. Re-simulation of real-time program (group C) about the image data in group B, data analysis was χ²-test by SPSS 13.0 software. Results The quality verification in two groups were 92% and 39%,the difference was statistically sifnificant (P=0.003). The re-simulation program in group C was 94%,there was significant difference compared with group B (P=0.001),but with no significant difference compared with group A (P=0.811). Conclusions The application of intraoperative real-time planning by CT guided with ¹²⁵I seed implantation brachytherapy to thoracic malignancies, non-equidistant layout that be the real implantedneedle trajectory based on dosimetry, can significantly improve the tumor target dose, operational, there was greatly important value to the standardization of the particle therapy of thoracic malignancies.

Objective To study the feasibility of contouring heart planning organ at risk volume (PRV) on kilovolt cone-beam CT (CBCT) images, and measure the margins for the PRV of heart based on planning CT images. Methods 15 early stage non-small cell lung cancer (NSCLC) patients accepted radiotherapy in our hospital were selected. For every case, CBCT scan was achieved before every fraction to correct the setup error, and the first 10 serious CBCT images were selected in present research. After contouring the heart on CBCT images according to the same standard, compared the differences of heart between CT and CBCT, analyzed the reproducibility of contouring the heart on different serious CBCT images, measured the margins in different axial direction from heart on planning CT to CBCT. Results The heart volume of planning CT was smaller than CBCTs with statistical difference (588 cm³ vs.717 cm³,P=0.000). The volumes based on different serious CBCT images were similar for every patient (P=0.999) and the coincidence of the hearts region on the same anatomical section between the first serious CBCT and others serious could reach to 0.985±0.020 without statistical significant difference (P=0.070). The mean margins for heart from planning CT to CBCT was (10.5 ± 2.8) mm,(5.9 ± 2.8) mm,(2.2 ± 1.6) mm,(3.3 ± 2.2) mm,(6.7 ± 1.1) mm and (4.5 ± 2.5) mm in the left, right, anterior and posterior direction;respectively. Conclusions The PRV of heart contouring based on CBCT was feasible. If there were no CBCT, 11 mm in left direction, 6 mm in right direction, 3 mm in head-foot direction, 7 mm in the anterior direction, and 5 mm in posterior direction should be applied to obtain the PRV of heart.

Objective To compare the dosimetry difference between helical tomotherapy and fixed field IMRT for breast cancer radiotherapy after breast-conserving surgery. Methods Ten patients received radiotherapy after breast-conserving surgery were selected. For each patient, two treatment plans (FF-IMRT plan and HT plan) were designed with Eclipse and TomoTherapy. Same institutional dose-volume constraints for breast cancer were used in both techniques. Targets and organs at risk were compared with paired t-test for two planning. Results In comparison with the FF-IMRT planning, PTV coverage of HT plan group increased, D_mean became lower (P=0.000,0.002). the HI and CI were significantly higher for HT (P=0.001,0.023).Compared with the FF-IMRT plans, V₅,V₁₀,V₂₀,V₃₀,V₄₀ and D_mean of the ipsilateral lung were reduced by about 28%,30%,35%,46%,61% and 32%(P=0.000),those of full lung were reduced by about 30%,28%,34%,46%,62% and 26%(P=0.000), those and D_max of heart were reduced by about 57%,59%,71%,82%,91%,45% and 12%(P=0.000—0.002).The D_mean and D_max of contralateral breast were higher by 0.9 Gy and 3.0 Gy (P=0.000,0.000) respectively, those of contralateral lung were higher by 0.42 Gy and 2.70 Gy (P=0.000,0.000) respectively. It takes significantly long time for the HT plans designed than FF-IMRT plan (11.98 min:5.96 min,P=0.000). Conclusions The HT planning improve the HI and CI of PTV, organs at risk can get equivalent or superior dose distribution compared with the FF-IMRT technology, but it is feasible for clinical applications in breast-conserving surgery as a new method.

To study a series of tests to the IMRT planning system RayStation, and verify the feasibility of this Standard. Referring to the standard"Performance and test methods for intensity modulated radiation therapy (IMRT) treatment planning system"(Standard). Methods Referring to the Standard, the tests include:dose goals used for planning, point dose calculation accuracy and dose distribution calculation accuracy. And test phantoms include:AAPM TG119 report′s test cases and solid water phantom for verification, and IMRT test cases include:multitarget, mock prostate, head/neck and CTshape (easier version and harder version) and so on. Referring to the Standard, we optimize and calculate doses of interest in RayStation, and use the common measurement equipments and tools, such as an ionization chamber, films, a detector array, and etc, to measure the doses on the accelerator, then calculate and analyze the errors between them. Results The results of dose goals for five different mock plans meet the requirements of the Standard. And the point dose ionization chamber measurements are in line with the requirements of the Standard, and the total error of the mock plans was (0.83±165)%. The γ pass rates of per field measurements using detector array are all greater than 990%, and the γ pass rates of composite film measurements are all greater than 925%. Conclusions The results of three trials to IMRT performance of RayStation are in full compliance with the requirements of the Standard. And also it is an evidence for the feasibility of this Standard.