Automatic segmentation of head and neck organs at risk based on three-dimensional U-NET deep convolutional neural network / 生物医学工程学杂志

The segmentation of organs at risk is an important part of radiotherapy. The current method of manual segmentation depends on the knowledge and experience of physicians, which is very time-consuming and difficult to ensure the accuracy, consistency and repeatability. Therefore, a deep convolutional neural network (DCNN) is proposed for the automatic and accurate segmentation of head and neck organs at risk. The data of 496 patients with nasopharyngeal carcinoma were reviewed. Among them, 376 cases were randomly selected for training set, 60 cases for validation set and 60 cases for test set. Using the three-dimensional (3D) U-NET DCNN, combined with two loss functions of Dice Loss and Generalized Dice Loss, the automatic segmentation neural network model for the head and neck organs at risk was trained. The evaluation parameters are Dice similarity coefficient and Jaccard distance. The average Dice Similarity coefficient of the 19 organs at risk was 0.91, and the Jaccard distance was 0.15. The results demonstrate that 3D U-NET DCNN combined with Dice Loss function can be better applied to automatic segmentation of head and neck organs at risk.

Dosimetric comparison of helical tomotherapy and volume-modulated arc therapy for upper thoracic esophageal carcinoma / 中华放射医学与防护杂志

Objective To compare the dosimetric differences between helical tomotherapy (HT) and volume-modulated arc therapy (VMAT) in the treatment of upper thoracic esophageal carcinoma (UTEC).Methods A total of 10 patients with UTEC were randomly selected.HT plan and double-arc VMAT plan were designed and optimized for each patient.The prescription dose was 50 Gy/30 fractions for gross target volume (GTV), 66 Gy/30 fractions for planned target volume (PTV).The dose distribution and conformal index (CI), homogeneity index (HI) of target volume, the D1％, D5％, Dg5％, D99％, and dose of organ at risk (OAR) were analyzed by using the dose volume histogram (DVH).The monitor units and delivery time were also evaluated.Results For GTV and PTV, the D99％ of HT plans were slightly higher than those of VMAT plans (t =4.476, 3.756, P ＜ 0.05) , but no significant differences in D1％ , D5％ , D95％ , HI and CI (P ＞ 0.05) were found.The V10, V15, V20 and mean lung dose (MLD) to the total-lung of HT plans were all significantly lower than those of VMAT plans (t =-3.369,-4.824, -4.869,-3.657, P ＜ 0.05).There were no significant differences for V5, V30 and Dmax of cord (P ＞ 0.05).The monitor units and delivery time of VMAT plans were significantly lower than those of HT plans (t =13.970, 7.982, P ＜ 0.05).Conclusions Both HT and VMAT are appropriate for esophageal cancer radiotherapy.HT significantly reduces the radiation dose of the total-lung, while VMAT has obvious advantages in efficiency.

Clinical research progress of radiotherapy in pharyngeal and laryngeal squamous cell carcinoma / 中国医学装备

Radiotherapy and chemotherapy are the main treatment means for locally advanced squamous cell carcinoma of the pharynx and larynx, to guarantee efficacy and avoid the damage of radical surgery, so as to preserve the laryngeal function of swallowing and pronunciation.With the progressing of radiotherapy technology,concept of treatment and radiotherapy mode have been advanced constantly,that have prolonged the survival time and improved the quality of life.This study will review the progress of radiotherapy in the pharynx and larynx squamous cell carcinoma, investigate the improvement of radiotherapy technology and hypofractionated IMRT, and provide reference for reducing the toxicity and after effects of radiotherapy.

Effect of hypofractionated intensity-modulated radiation therapy on acute toxicities for locally advanced squamous cell carcinoma of the hypopharynx / 中国肿瘤临床

Objective: To evaluate the feasibility of hypofractionated intensity-modulated radiation therapy (IMRT) combined with concurrent chemotherapy in patients with locally advanced squamous cell carcinoma of the hypopharynx. Methods:Patients with stageⅢ-ⅣA carcinoma of the hypopharynx were treated with IMRT and cisplatin-based concurrent chemotherapy. Two groups were di-vided according to the prescription dose to the primary gross tumor volume, as follows:Cohort-1 comprised patients who were recruit-ed before February 2013 (70 Gy/33 F and 2.12 Gy/F);and Cohort-2 comprised patients who were recruited since February 2013 (69 Gy/30 F and 2.30 Gy/F). Acute toxicities were evaluated. This study was registered with the number ChiCTR-ONRC-14004240. Results:Between August 2008 and December 2014, a total of 76 patients (35 in Cohort-1 and 41 in Cohort-2) were recruited. No xerostomia of grade 3 and higher was observed in all patients, who showed low incidences of grade 3 skin reaction, oral mucositis, and dysphagia. All patients did not show acute toxicities of higher than grade 4. No statistical differences in acute toxicities were observed between the two cohorts. No statistical difference was observed in acute toxicities between the IMRT techniques. Induction chemotherapy was the inde-pendent prognostic factor for grade 2 xerostomia (P=0.002). Conclusion:The 69 Gy/30 F hypofractionated IMRT was safe and effec-tive in the treatment of locally advanced squamous cell carcinoma of the hypopharynx. Late toxicities and long-term outcome need to be investigated further.

Effect of adaptive replanning on adverse reactions and clinical outcome in nasopharyngeal carcinoma treated by helical tomotherapy / 中南大学学报(医学版)

OBJECTIVE@#To observe the effect of adaptive replanning on adverse reactions and clinical outcome of nasopharyngeal carcinoma treated by helical tomotherapy.@*METHODS@#Fifty nasopharyngeal carcinoma patients treated by TomoTherapy system were retrospectively analyzed. Among these patients, 25 received repetitive CT simulation and replanning, and another 25 case-matched control patients without replanning were identified by matching age, gender, pathological type, UICC stage, weight loss, etc. Wilcoxon test was used to evaluate the effect of replanning on acute and chronic radiation reactions within individuals. Kaplan-Meier study was used to estimate the survival of patients with or without replanning.@*RESULTS@#There was a significant difference in late salivary grand damage between the replanning and the control group (P=0.046), while no difference was observed in acute or other late side effects between the two groups. The median follow-up of the two groups was 32 months (7-42 months) and 26 months (8-46 months), respectively. The median local relapse-free survival time, 2-year local relapse-free survival and 2-year lymphnode relapse-free survival in the two groups were similar (36 months, 92% and 100%). No significant difference was found in the 2-year metastasis relapsefree survival (80% and 96%) and the 2-year overall survival between the two groups (88% and 92%, P>0.05).@*CONCLUSION@#Adaptive replanning may reduce the severity of late damage of salivary glands after helical tomotherapy in nasopharyngeal carcinoma patients without improvement of 2-year survival rate.

Dosimetric evaluation of three techniques in postoperative radiotherapy for rectal cancer / 中华放射医学与防护杂志

Objective To evaluate the dosimetric characteristics of helical tomotherapy (HT),intensity-modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D-CRT) for postoperative radiotherapy of rectal cancer.Methods Ten male patients with stage Ⅱ or Ⅲ middle or low position rectal cancer were selected retrospectively.All of the 10 patients underwent Dixon surgery and CT simulation orientation.The target volumes and normal organs were drawn in the CT images and the plans for HT,IMRT and 3D-CRT were designed.The prescribed dose was given 50 Gy in 25 fractions,covering at least 95％ of the planning target volume.Results All plans met the needs of the prescribed doses.The HT and IMRT plans met the needs of dose limit to organs at risk,however,the 3D-CRT plans failed to do that.The conformity indexes of HT,IMRT and 3D-CRT plans were 0.86,0.82 and 0.62,respectively (F =206.81,P ＜ 0.001),and the homogeneity indexes were 0.001,0.157,and 0.205,respectively (x2 =15.8,P ＜ 0.001).The 3D-CRT plans had larger volumes than the HT plans and IMRT plans in the high-dose regions such as pelvic V50,bladder V40,bowel V50 and femoral head D5 (P ＜ 0.05),but the differences between the HT plans and IMRT plans were not statistically significant (P ＞0.05).The V15 value of bowel of HT plans were higher than those of the IMRT and 3D-CRT plans (71.1％ vs.63.3％ and 67.7％,respectively).However,there was no significantly difference.Conclusions All of the HT,IMRT and 3D-CRT plans are able to meet the prescription dose requirement of the target regions of rectal cancer.The HT plans show the best dose homogeneity and target conformity,followed by the IMRT plans,and then the 3D-CRT plans.The HT plans meet the needs of all OARs slightly better than the IMRT plans.3D-CRT plans are simple and practical with poor protective ability toward the OARs.

Clinical observation in nasopharyngeal carcinoma (NPC) treated with the anti-EGFR monoclonal antibody followed by helical tomotherapy / 中华放射医学与防护杂志

Objective To evaluate the clinical outcome and the acute toxicity in nasopharyngeal carcinoma (NPC) treated with tomotherapy followed by the anti-EGFR monoclonal antibody.Methods Between March 2008 and November 2009,34 newly diagnosed NPC patients were treated with helical tomotherapy combined with nimotuzumab or cetuximab.All the patients underwent tomotherapy at the dose of 70 Gy/33F for the gross tumor volume (pGTVns) and positive lymphnodes (GTVnd) ,and 60 Gy/33F for the high risk clinical target volume (PTV1),and 56 Gy/33 F for the low risk clinical target volume (PTV2),respectively.17 patients in group N were given weekly injection of 200 mg for 6-7 times and 17 patients in group C were given initial dosage 400 mg/m2 followed by subsequent weekly dosage of 250 mg/m2 for 6-7 times.Acute lesions were evaluated with the RTOG/EORTC criteria.Result The median follow-up time was 22 months.The effective rates (CR + PR) in 3,6 and 12 months were 14/17,12/17,12/17 in group N and 15/17,14/17,14/17 in group C.The 1 year survival rate was 15/17 in group Nand 17/17 in group C.Nimotuzumab had less acute mucositis reaction (u = 2.25,P < 0.05),weight loss(t=2.56,P=0.02) and rash (u=4.36,P＜0.01) compared with cetuximab.Conclusions Helical tomotherapy combined with nimotuzumab or cetuximab was effective and made no difference in the shortterm efficacy and 1 year survival rate for the patients with NPC.Nimotuzumab has less acute reaction than cetuximab.More studies should be done to prove long-term effects.