Dosimetric comparison of three?dimensional conformal radiation therapy, intensity?modulated radiation therapy, and volumetric?modulated arc therapy for free?breathing whole?breast irradiation: A planning study

Background: Currently, recommended heart dose constraints are difficult to meet in whole?breast irradiation (WBI) for left?sided breast cancer patients, who cannot be treated with the deep inspiration breath hold. We performed a radiotherapy planning study to establish if the use of intensity?modulated radiation therapy (IMRT) or volumetric?modulated arc therapy (VMAT) allows for better sparing of the heart and its subvolumes than the three?dimensional conformal radiation therapy (3D?CRT), and how these attempts affect the dose delivered to the other organs. Methods: A total of 17 left?sided and 10 right?sided consecutive patients treated with free?breathing WBI were retrospectively included. The 3D?CRT, IMRT, and VMAT plans were generated. Several dose杤olume parameters and plan quality indices were compared, separately for the left? and right?sided plans. Results: All the techniques fulfilled the planning objectives. In the left?sided plans, there was no heart or left ventricle dose reduction with IMRT, nor with VMAT; the maximum dose in the left anterior descending coronary artery was reduced with VMAT (P = 0.005); V5 for the contralateral breast, contralateral lung, and total?body increased markedly in VMAT, and for the ipsilateral lung (V5IL) also in IMRT, compared with 3D?CRT (P < 0.001). In the right?sided plans, the V5 values, except for V5IL, did not differ between the three techniques. Conclusions: IMRT and VMAT had a limited heart?sparing benefit in the left?sided free?breathing WBI, at the cost of increased low?dose volumes, measured by V5. The low?dose volumes are not increased by IMRT or VMAT in the right?sided WBI, where heart sparing is not a problem, but the attempts to reduce cardiac doses in the left?sided WBI increase them.

Analysis of risk factors of radiation-induced toxicity in limited-stage small cell lung cancer treated with hypofractionated intensity-modulated radiotherapy / 中华肿瘤杂志

Objective: To compare the incidence of radiation-related toxicities between conventional and hypofractionated intensity-modulated radiation therapy (IMRT) for limited-stage small cell lung cancer (SCLC), and to explore the risk factors of hypofractionated radiotherapy-induced toxicities. Methods: Data were retrospectively collected from consecutive limited-stage SCLC patients treated with definitive concurrent chemoradiotherapy in Cancer Hospital of Chinese Academy of Medical Sciences from March 2016 to April 2022. The enrolled patients were divided into two groups according to radiation fractionated regimens. Common Terminology Criteria for Adverse Events (CTCAE, version 5.0) was used to evaluate the grade of radiation esophagus injuries and lung injuries. Logistic regression analyses were used to identify factors associated with radiation-related toxicities in the hypofractionated radiotherapy group. Results: Among 211 enrolled patients, 108 cases underwent conventional IMRT and 103 patients received hypofractionated IMRT. The cumulative incidences of acute esophagitis grade ≥2 [38.9% (42/108) vs 35.0% (36/103), P=0.895] and grade ≥ 3 [1.9% (2/108) vs 5.8% (6/103), P=0.132] were similar between conventional and hypofractionated IMRT group. Late esophagus injuries grade ≥2 occurred in one patient in either group. No differences in the cumulative incidence of acute pneumonitis grade ≥2[12.0% (13/108) vs 5.8% (6/103), P=0.172] and late lung injuries grade ≥2[5.6% (6/108) vs 10.7% (11/103), P=0.277] were observed. There was no grade ≥3 lung injuries occurred in either group. Using multiple regression analysis, mean esophageal dose ≥13 Gy (OR=3.33, 95% CI: 1.23-9.01, P=0.018) and the overlapping volume between planning target volume (PTV) and esophageal ≥8 cm(3)(OR=3.99, 95% CI: 1.24-12.79, P=0.020) were identified as the independent risk factors associated with acute esophagitis grade ≥2 in the hypofractionated radiotherapy group. Acute pneumonitis grade ≥2 was correlated with presence of chronic obstructive pulmonary disease (COPD, P=0.025). Late lung injuries grade ≥2 was correlated with tumor location(P=0.036). Conclusions: Hypofractionated IMRT are tolerated with manageable toxicities for limited-stage SCLC patients treated with IMRT. Mean esophageal dose and the overlapping volume between PTV and esophageal are independently predictive factors of acute esophagitis grade ≥2, and COPD and tumor location are valuable factors of lung injuries for limited-stage SCLC patients receiving hyofractionated radiotherapy. Prospective studies are needed to confirm these results.

Research progress on the bone-marrow sparing intensity-modulated radiotherapy for cervical cancer / 中华放射肿瘤学杂志

The cisplatin-based concurrent chemoradiotherapy (CCRT) has been accepted as a standard treatment for most locally advanced cervical cancer. Compared with radiation therapy alone, CCRT can increase tumor control and survival rates, whereas it also can increase the incidence of acute hematological toxicity, which results in the treatment interruption or delay, and may even affect clinical efficacy and prognosis of patients. Therefore, how to reduce the incidence and severity of acute hematological toxicity induced by CCRT is a hot spot of clinical research. Previous studies have demonstrated that the occurrence of hematological toxicity is associated with the volume and dose of irradiated pelvic bone marrow. With the development of modern radiotherapy technology, precise radiotherapy technologies, such as intensity-modulated radiotherapy (IMRT) and image-guided radiotherapy (IGRT), not only guaranteed the enough dose for tumor, but also realized the protection of normal tissues. This article will focus on the feasibility of bone marrow sparing during CCRT for cervical cancer, and summarize the research progress in recent years.

Correlation between monitor units and pass rate of plan dose verification in VMAT plan for different cancers / 中华放射肿瘤学杂志

Objective:To analyze the correlation between the monitor units and pass rate of plan dose verification in the volumetric intensity modulated arc therapy (VMAT) plan.Methods:VMAT plans for 20 patients with nasopharyngeal carcinoma (NPC) and 30 patients with cervical cancer who underwent radiotherapy at Liuzhou Workers' Hospital from January to October 2020 were retrospectively chosen. The Detector 1500 array and Octavius 4D phantom from German PTW company were used for dose measurement. The pass rates of dose verification of relevant plans were analyzed under the conditions of 3%/2 mm and 2%/2 mm. The correlation between the monitor units and pass rate of plan dose verification in VMAT plans was assessed by Pearson's bivariate correlation analysis.Results:Under the condition of 3%/2 mm, the correlation coefficients between the monitor units and gamma pass rate were -0.873 ( P<0.001), -0.800 ( P<0.001), -0.781 ( P<0.001), -0.493 ( P=0.006) for NPC_1Arc, NPC_2Arc, NPC_1Arc+NPC_2Arc and Cervix_2Arc, respectively. Under the condition of 2%/2 mm, the correlation coefficients between the monitor units and gamma pass rate were -0.842 ( P<0.001), -0.770 ( P<0.001), -0.748 ( P<0.001) and -0.531 ( P=0.003) for NPC_1Arc, NPC_2Arc, NPC_1Arc+NPC_2Arc and Cervix_2Arc, respectively. Conclusion:Significant negative correlation can be observed between the monitor units and plan dose verification pass rate in VMAT plan.

Phase II trial of hippocampal avoidance whole-brain irradiation with simultaneous integrated boost for treatment of brain metastases of lung cancer / 中华放射肿瘤学杂志

Objective:To evaluate the efficacy and safety of hippocampal avoidance whole-brain irradiation with simultaneous integrated boost in the treatment of brain metastases of lung cancer.Methods:Forty lung cancer patients with brain metastases who received whole-brain radiotherapy with simultaneous integrated boost and hippocampal avoidance in Cancer Hospital, Chinese Academy of Medical Sciences from 2014 to 2020 were enrolled in this study. Brain MRI, survival follow-up and evaluation of side effects were performed before radiotherapy and at 1, 3, 6 and 12 months after radiotherapy, respectively. Overall survival (OS), progression-free survival (PFS) and changes in cognitive function were analyzed. Continuous data were described as Mean ± SD. Categorical data were described by frequency and composition ratio or percentage. Survival analysis was conducted by Kaplan-Meier method. Influencing factors of survival were identified by univariate and multivariate Cox's regression analyses.Results:A total of 40 patients were enrolled in the study. The median follow-up time was 14.2 months and the median OS, PFS and intracranial PFS of all patients were 14.8 months, 6.7 months and 14.8 months, respectively. Multivariate analysis showed that male gender and newly diagnosed stage Ⅳ disease were associated with worse OS and PFS, respectively. The Hopkins verbal learning test-revised (HVLT-R) scores at baseline and 1, 3 and 6 months after radiotherapy were 21.94±2.99, 20.88±3.12, 20.03±3.14, and 19.78±2.98, respectively. The HVLT-R score at 6 months after radiotherapy was decreased by approximately 9.8% compared with the baseline. No grade 3 or above toxic and side effect occurred in the entire cohort.Conclusion:Hippocampal avoidance whole-brain irradiation with simultaneous integrated boost is a safe and effective treatment for brain metastases of lung cancer, which is expected to reduce the impact of radiotherapy on cognitive function.

Correlation between acute intestinal toxicity and dose-volume parameters in patients with cervical cancer receiving postoperative adjuvant radiotherapy / 中华放射肿瘤学杂志

Objective:To identify dose-volume parameters to predict the incidence of acute intestinal toxicity in cervical cancer patients after postoperative adjuvant radiotherapy.Methods:Clinical data of 93 cervical cancer patients who underwent postoperative adjuvant intensity-modulated radiotherapy (IMRT) were retrospectively evaluated. The dose-volume parameters comprised the absolute volume of the bowel receiving 5-45 Gy (5 Gy interval) radiation dose and the total volume of the bowel. The acute radiation-induced intestinal toxicity was evaluated by Radiation Therapy Oncology Group (RTOG) criteria. The association between the irradiated bowel volume and acute intestinal toxicity was analyzed.Results:A total of 26 (28%) patients experienced grade ≥2 acute intestinal toxicity. A strong relationship between grade ≥2 acute intestinal toxicity and the irradiated small bowel volume was observed at the total volume of small bowel, small bowel V 5 Gy, V 10 Gy and V 15 Gy (all P<0.05). Small bowel V 10 Gy ( HR=1.028, 95% CI, 0.993-1.062, P=0.029) and small bowel ?V 15 Gy( HR=0.991, 95% CI, 0.969-1.013, P=0.034)were the independent risk factors for evident acute intestinal toxicity. Conclusion:Dose-volume parameters of the small bowel can be used as predictors for the occurrence of grade ≥2 acute intestinal toxicity in cervical cancer patients undergoing postoperative adjuvant radiotherapy.

Radiomics-based prediction of gamma pass rates for different intensity-modulated radiation therapy techniques for pelvic tumors / 中华放射医学与防护杂志

Objective:To explore the feasibility of a classification prediction model for gamma pass rates (GPRs) under different intensity-modulated radiation therapy techniques for pelvic tumors using a radiomics-based machine learning approach, and compare the classification performance of four integrated tree models.Methods:With a retrospective collection of 409 plans using different IMRT techniques, the three-dimensional dose validation results were adopted based on modality measurements, with a GPR criterion of 3%/2 mm and 10% dose threshold. Then prediction were built models by extracting radiomics features based on dose documentation. Four machine learning algorithms were used, namely random forest (RF), adaptive boosting (AdaBoost), extreme gradient boosting (XGBoost), and light gradient boosting machine (LightGBM). Their classification performance was evaluated by calculating sensitivity, specificity, F1 score, and AUC value. Results:The RF, AdaBoost, XGBoost, and LightGBM models had sensitivities of 0.96, 0.82, 0.93, and 0.89, specificities of 0.38, 0.54, 0.62, and 0.62, F1 scores of 0.86, 0.81, 0.88, and 0.86, and AUC values of 0.81, 0.77, 0.85, and 0.83, respectively. XGBoost model showed the highest sensitivity, specificity, F1 score, and AUC value, outperforming the other three models. Conclusions:To build a GPR classification prediction model using a radiomics-based machine learning approach is feasible for plans using different intensity-modulated radiotherapy techniques for pelvic tumors, providing a basis for future multi-institutional collaborative research on GPR prediction.

The efficacy analysis of moderately hypofractionated IMRT combined with androgen deprivation therapy for locally advanced prostate cancer / 中华放射医学与防护杂志

Objective:To investigate the efficacy and adverse reactions of moderately hypofractionated intensity modulated radiation therapy (IMRT) combined with androgen deprivation therapy (ADT) for locally advanced prostate cancer (LAPC).Methods:This study retrospectively analyzed the medical records of 40 LAPC patients who were admitted in The Second Hospital of Dalian Medical University during 2014-2020. The planning gross target volume (PGTV) dose for prostate gland and seminal vesicle gland was 64.8-70.0 Gy/25-28 f, 2.4-2.8 Gy/f and the dose of PGTVnd in 20 cases with positive pelvic lymph nodes was 60.0-64.4 Gy/25-28 f, 2.3-2.4 Gy/f. The dose of planning target volume (PTV) for the drainage area of pelvic lymph nodes was 45.0-50.4 Gy/25-28 f. The enrolled patients were treated with long-term ADT, including neoadjuvant, simultaneous, and adjuvant therapies. The efficacy and adverse reactions were evaluated. The prognostic factors affecting the biochemical failure-free survival (BFFS) were analyzed.Results:The median follow-up time was 31 months. The 2- and 3-year overall survival (OS) rates were 100% and 96.9%, respectively. The 1-, 2-, and 3-year BFFS rates were 90%, 76.8% and 72%, respectively. The 1-, 2-, and 3-year distant metastasis-free survival (DMFS) rates were 92.2%, 82.8% and 75.1%, respectively. Gleason (GS) score ( χ2=10.00, P < 0.05) and adjacent tissue invasion ( χ2=8.85, P<0.05) were prognostic factors related to BFFS for LAPC. Adjacent tissue invasion and GS 9-10 were independent poor prognostic factors. The incidence of acute urinary adverse reaction and rectal injury (grade≥2) was 7.5% and 20%, respectively. The incidence of late urinary adverse reaction and rectal injury (grade≥2) was 12.5% and 17.5%, respectively. Adverse reactions at grade 3-4 did not occur. Conclusions:The moderately hypofractionated IMRT combined with ADT is feasible for LAPC treatment, achieving satisfactory survival effects. 70 Gy/25-28 f, 2.5-2.8 Gy/f is a safe and effective moderate hypofraction scheme. Adjacent tissue invasion and GS score are prognostic factors related to BFFS for LAPC.

Effects of Onodera′s prognostic nutritional index on the prognosis of locally advanced oropharyngeal squamous cell carcinoma after induction chemotherapy followed by sequential chemoradiotherapy / 中华放射医学与防护杂志

Objective:To explore the effects of Onodera′s prognostic nutritional index (PNI) on the prognosis of locally advanced oropharyngeal squamous cell carcinoma (LA-OPSCC) after induction chemotherapy followed by sequential chemoradiotherapy.Methods:A retrospective analysis was conducted on the clinical data of 52 LA-OPSCC patients receiving induction chemotherapy followed by sequential chemoradiotherapy in The Affiliated Cancer Hospital of Guizhou Medical University during 2014-2018. The PNI values of all the patients at different treatment phases were statistically analyzed, and the ROC curve was employed to determine the optimal critical value of PNI. The patients in this study were divided into a well-nourished group ( n = 27) and a poorly-nourished group ( n = 25). The Kaplan-Meier method was used for survival analysis. The Cox proportional hazards model was utilized to analyze the relationships between different nutritional status and prognosis. Clinical features and adverse reactions were compared between the two groups. Results:The PNI values decreased significantly after radiotherapy, with an optimal critical value of 42.4. The 5-year overall survival (OS) and progression-free survival (PFS) of the well-nourished group (PNI ≥ 42.4) were 62.6% and 60.9%, respectively, which were significantly higher than those (30.1% and 29.7%) of the poorly-nourished group (PNI < 42.4, χ2 = 11.12, 5.74, P < 0.05). The multivariate analysis showed that PNI was an independent prognostic factor for the OS after radiotherapy ( HR = 2.752, 95% CI: 1.095-6.917, P = 0.031). The LA-OPSCC patients aged over 60 years or those who did not respond to induction chemotherapy accounted for a higher proportion of malnutrition after chemoradiotherapy ( χ2 = 4.89, 5.05, P < 0.05). Conclusions:PNI after radiotherapy can be used as a prognostic factor in the evaluation of LA-OPSCC patients receiving induction chemotherapy followed by sequential chemoradiotherapy. The LA-OPSCC patients aged over 60 years or those who do not respond to induction chemotherapy should receive more nutritional support during the chemoradiotherapy.

Prediction of radiomics-based machine learning in dose verification of intensity-modulated pelvic radiotherapy / 中华放射医学与防护杂志

Objective:Based on radiomics characteristics, different machine learning classification models are constructed to predict the gamma pass rate of dose verification in intensity-modulated radiotherapy for pelvic tumors, and to explore the best prediction model.Methods:The results of three-dimensional dose verification based on phantom measurement were retrospectively analyzed in 196 patients with pelvic tumor intensity-modulated radiotherapy plans. The gamma pass rate standard was 3%/2 mm and 10% dose threshold. Prediction models were constructed by extracting radiomic features based on dose documentation. Four machine learning algorithms, random forest, support vector machine, adaptive boosting, and gradient boosting decision tree were used to calculate the AUC value, sensitivity, and specificity respectively. The classification performance of the four prediction models was evaluated.Results:The sensitivity and specificity of the random forest, support vector machine, adaptive boosting, and gradient boosting decision tree models were 0.93, 0.85, 0.93, 0.96, 0.38, 0.69, 0.46, and 0.46, respectively. The AUC values were 0.81 and 0.82 for the random forest and adaptive boosting models, respectively, and 0.87 for the support vector machine and gradient boosting decision tree models.Conclusions:Machine learning method based on radiomics can be used to construct a prediction model of gamma pass rate for specific dosimetric verification of pelvic intensity-modulated radiotherapy. The classification performance of the support vector machine model and gradient boosting decision tree model is better than that of the random forest model and adaptive boosting model.

Efficacy of intensity modulated radiotherapy with sequential chemotherapy in the treatment of high-grade glioma and analysis of influential factors / 中国基层医药

Objective:To investigate the efficacy of intensity-modulated radiotherapy with sequential chemotherapy in the treatment of high-grade glioma and analyze the influential factors.Methods:A total of 56 patients with high-grade glioma who received treatment in Yantai Municipal Laiyang Central Hospital from January 2014 to January 2016 were retrospectively analyzed. All patients underwent three-dimensional conformal radiotherapy or enhanced radiotherapy. The use of bevacizumab, pathological grade, and preoperative and postoperative Karnofsky Performance Status scores in all patients were recorded. Cox and other proportional risk regression models were used to analyze the predictors of patient mortality and receiver operating characteristic (ROC) curve analysis was performed.Results:All patients were followed up to April 2022. Follow-up results showed that the median survival time of patients receiving concurrent chemotherapy with temozolomide and adjuvant chemotherapy with temozolomide was 11.6 months. Univariate analysis showed that pathological grade, Karnofsky Performance Status scores, and the degree of tumor resection were correlated with the prognosis of patients ( P = 0.022, 0.049, 0.022). Multivariate analysis showed that the degree of tumor resection and pathological grade were the independent influential factors of prognosis ( P = 0.010, 0.010). Survival curve analysis revealed that the median survival time of patients subjected to total tumor resection was 12.6 months and that of patients subjected to partial tumor resection was 4.8 months. The median survival time of patients subjected to total tumor resection was longer than that of patients subjected to partial tumor resection. The median survival time of patients with WHO grade Ⅲ tumors was 25.2 months, and it was 6.3 months for patients with WHO grade Ⅳ tumors. The median survival time of patients with WHO grade Ⅲ tumors was longer than that of patients with WHO grade Ⅳ tumors. The receiver operating characteristic curve analysis results showed that the area under the receiver operating characteristic curve plotted for using WHO classification of tumors in the neurological system and surgical methods to predict the death of patients with high-grade glioma was 0.783 and 0.814, respectively. WHO tumor grade and surgical methods for prediction of prognosis of high-grade glioma had high accuracy. Conclusion:Low pathological grade and total resection are independent protective factors for the prognosis of patients with high-grade glioma.

Adaptive extended‑field intensity-modulated radiation therapy with simultaneously integrated boost for locally advanced cervical cancer with lymph node metastases / Philippine Journal of Obstetrics and Gynecology

@#Performing external beam radiotherapy alone without chemotherapy or brachytherapy for locally advanced cervical cancer with multiple lymph node metastases is challenging. The purpose of this case report is to present the efficacy of high‑dose adaptive extended‑field intensity‑modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) in treating locally advanced cervical cancer with multiple lymph node metastases. A 67‑year‑old woman with locally advanced squamous cell carcinoma of the uterine cervix was treated by external beam radiotherapy alone due to the refusal of chemotherapy and intracavitary brachytherapy. In order to maximize the efficacy of treatment, extended‑field radiotherapy that includes the paraaortic lymph nodes as well as an adaptive IMRT‑SIB plan, was applied. The treatment was successful, resulting in complete tumor disappearance without severe adverse events. In conclusion, high‑dose adaptive IMRT‑SIB may be an alternative treatment option for locally advanced cervical cancer with multiple lymph node metastases.

Analysis of dosimetric differences between active control and passive tracking of jaws / 中国辐射卫生

Objective To analyze the effect of the fixed-jaw technique on dosimetric parameters during dynamic intensity-modulated radiotherapy (DIMRT) planning. Methods Ten patients each with nasopharyngeal carcinoma, postoperative cervical cancer, and right breast cancer after radical surgery were selected for this study; all patients underwent DIMRT in our hospital in 2020. After administration at the prescribed dose, two methods were used to design the radiotherapy plan for each patient: split-field technique (SFT) and fixed-jaw technique (FJT). The two plans were compared for the differences in the dosimetric parameters and plan verification pass rate. Results Compared with SFT, FJT showed significant decreases (P <0.05) in the following parameters for patients with nasopharyngeal carcinoma, postoperative cervical cancer, and right breast cancer after radical surgery: number of radiation fields (down by 41.5%, 47.3%, and 34.9%, respectively, t = 7.954, 24.2, and 4.949, respectively), total number of monitor units (MUs) (down by 5.6%, 5.3%, and 13.5%, respectively, t = 3.211, 2.423, and 5.481, respectively), and actual beam-on time (down by 25.3%, 23.8%, and 13.6%, respectively, t = 5.814, 9.208, and 5.655, respectively). There were significant differences in some of the dosimetric parameters for all three types of cancer patients between the two plans (P <0.05). There were no significant differences in the plan verification pass rate (P >0.05). Conclusion FJT can reduce the total number of MUs and actual beam-on time while meeting the requirements for clinically prescribed doses in DIMRT planning.

Effect of couch rotation angle on non-coplanar static intensity-modulated radiotherapy plan for gastric cancer / 中国辐射卫生

Objective To investigate the effect of couch rotation angle on non-coplanar static intensity-modulated radiotherapy (IMRT) plan for gastric cancer and to provide a reference for clinical planning. Methods A retrospective analysis was conducted on patients who recently underwent postoperative IMRT for gastric cancer. Twenty patients who received radiotherapy in the centre of Radiation Oncology of Huanggang Central Hospital from August 2022 to January 2023 were selected. That were selected to receive a seven-field coplanar static IMRT plan based on a couch rotation angle of 0° as the control group. Then, based on the coplanar IMRT plan, only the couch rotation angle of gantry angles 30° and 330° was changed to 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, respectively, and nine different non-coplanar plans were established. The homogeneity index (HI), conformity index (CI) of the target volume, and monitor unit (MU), as well as Dmean, V20, and V30 of the left and right kidneys, Dmax, Dmean, V10, V20, and V30 of the spinal cord, and Dmax, Dmean, V10, V20, V30, and V40 of the small intestine and liver were compared among the 10 plans. The MU and the dosimetric parameters of the target volumes and When the couch rotation angle was 60°, the minimum HI and maximum CI of the target volume were 0.0714±0.0089 and 0.9271±0.0108, respectively, and the minimum MU was 438±26, with the best homogeneity and conformity in the target volume and the shortest machine treatment time (P＜0.05). When the couch rotation angle was 10°, the Dmax of the small intestine was lowest, being (4620.73±99.27) cGy. When the couch rotation angle was 60°, the Dmean of the left and right kidneys was lowest, being (1246.30±130.35) cGy and (1001.52±103.33) cGy, respectively; the V20 of the left and right kidneys was lowest, being 22.87±6.29 and 19.69±1.84, respectively; the V10 and V30 of the spinal cord were lowest, being 40.08±4.92 and 1.68±0.34, respectively (P＜0.05). Conclusion The couch rotation angle has some influence on the postoperative treatment planning for patients with gastric cancer. In the design of non-coplanar plan for gastric cancer, the couch rotation angle of 60° contributes to establishing a better radiotherapy plan.

Dosimetric comparison of intensity-modulated photon radiotherapy and intensity-modulated proton radiotherapy for non-small cell lung cancer / 肿瘤研究与临床

Objective:To investigate the difference of dose distribution between intensity-modulated photon radiotherapy (IMRT) and intensity-modulated proton radiotherapy (IMPT) in patients with non-small cell lung cancer.Methods:The clinical data of 8 patients with stage Ⅱ-Ⅲ non-small cell lung cancer who received radiotherapy in Ion Medical center of the First Affiliated Hospital of University of Science and Technology of China from November 2020 to April 2022 were retrospectively analyzed. IMRT and IMPT radiotherapy plans were created for each patient separately, the main evaluation indicators were targeted area dose distribution parameters [homogeneity index (HI), conformity index (CI) and the percent volume of volume wrapped by 95% and 100% of prescription dose profile in the targeted area (V 95% and V 100%)], and the average dose (D mean) to the organ at risk and the percent volume of a certain relative biological effect (RBE) dose exposure [D mean, V 5 Gy(RBE) and V 20 Gy(RBE) of ipsilateral lung, D mean, V 5 Gy(RBE) and V 20 Gy(RBE) of bilateral lung, D mean, V 30 Gy(RBE) and V 40 Gy(RBE) of heart, maximum dose (D max) of spinal cord, and D mean of esophageal]. Results:In comparison with IMRT, IMPT reduced the levels of dose parameters in bilateral lung, ipsilateral lung, spinal cord, esophagus, and heart with statistically significant differences (all P < 0.05), especially in D mean of bilateral lung [(4.1±1.8) Gy (RBE) vs. (6.9±1.9) Gy (RBE)], V 5 Gy(RBE) [(15.9±7.1) % vs. (28.5±8.6)%], V 20 Gy(RBE) [(7.4±3.5)% vs. (10.1±3.5)%], and D mean of ipsilateral lung [(9.1±4.5) Gy (RBE) vs. (11.9±3.3) Gy (RBE)], all decreased significantly (all P < 0.001), but the differences in the levels of targeted area dose distribution parameters between them were not statistically significant (all P > 0.05). Conclusions:For patients with non-small cell lung cancer, IMPT is superior to IMRT in the protection of bilateral lung, ipsilateral lung, spinal cord, esophagus and heart.

Efficacy and safety of image-guided hypofractionated intensity-modulated radiotherapy combined with contralateral esophageal protection in treatment of unresectable stage Ⅲ non-small cell lung cancer / 肿瘤研究与临床

Objective:To explore the efficacy and adverse reactions of image-guided hypofractionated intensity-modulated radiotherapy (Ig-HypoRT) conbined with contralateral esophageal protection in treatment of patients with unresectable stage Ⅲ non-small cell lung cancer (NSCLC).Methods:The clinical data of 45 patients with unresectable stage Ⅲ NSCLC who were admitted to Xuzhou Cancer Hospital from January 2016 to January 2019 were retrospectively analyzed. Patients received induction chemotherapy with a platinum-based dual-drug combination regimen, followed by Ig-HypoRT with a total dose of tumor of 60-63 Gy/12- 18 times at 3.5-5.0 Gy/time. Contralateral esophagus was delineated as an organ at risk during radiotherapy, limiting V 45 Gy≤1.8 cc and V 55 Gy ≤0.4 cc. Patients' efficacy, survival and the occurrence of adverse reactions were observed. Results:Among 45 patients, there were 9 cases of complete remission, 31 cases of partial remission, 4 cases of stable disease and 1 case of disease progression, and the effective rate was 88.8% (40/45). The median follow-up time was 34 months, 45 patients had a median overall survival (OS) time of 25.0 months (95% CI 21.7-28.8 months), with 1-, 2-, and 3-year OS rates of 78.9%, 56.8% and 47.7%, respectively; the median progression-free survival (PFS) time was 18.5 months (95% CI 15.0-22.0 months), with 1-, 2- and 3-year PFS rates of 59.8%, 32.6% and 18.6%, respectively. The 3-year local recurrence rate was 9% (4/45). The incidence of grade 1-2 radioactive esophagitis was 80% (36/45); the incidence of grade 1-2 chest pain was 20% (9/45). The incidence of grade 3-4 adverse reactions were 13% (6/45), including 7% (3/45) of grade 3 pulmonary atelectasis, 4% (2/45) of grade 3 radioactive pneumonia, and 2% (1/45) of grade 4 hemoptysis. Conclusions:Ig-HypoRT combined with contralateral esophageal protection for unresectable stage Ⅲ NSCLC can improve survival rate and reduce esophageal adverse reactions of patients.

The effects of intensity modulated radiation and the risk factors of radiation pneumonia in elderly patients with esophageal cancer / 中国医师进修杂志

Objective:To investigate the effects of intensity modulated radiation therapy (imRT) and risk factors of radiation pneumonia caused by imRT in elderly patients with esophageal cancer.Methods:The clinical data of 80 elderly patients diagnosed with esophageal cancer and performed imRT in Traditional Chinese Medicine Hospital of Kunshan from February 2018 to February 2020 were analyzed, and the therapeutic effect and the incidence of adverse reactions were counted.Results:In the 80 patients, 13 patients occurred radiation pneumonia.The results of univariate analysis showed that the gender, smoking history, pathological stage and age had no correlation with radiation pneumonia ( P> 0.05), while tumor location, diabetes, concurrent chemotherapy, reradiotherapy and chronic obstructive pulmonary disease had correlation with the occurrence of radioactive pneumonia ( P<0.05). The levels of V30, V35, V40 between radioactive pneumonia patients and non-radioactive pneumonia patients had no significant differences ( P>0.05), but the levels of V5, V10, V15, V20 and mean lung dose(MLD) between radioactive pneumonia patients and non-radioactive pneumonia patients had significant differences ( P<0.05). The effect of imRT was no remission in 9 cases (11.25%), partial remission in 59 cases (73.75%) and complete remission in 12 cases (15.00%), and the clinical effective rate was 88.75%(71/80). By comparing the adverse reactions caused by imRT, it was found that the incidence of radiation esophagitis, leukopenia, and acute radiation pneumonia were 93.75%(75/80), 12.50%(10/80) and 22.50%(18/80), respectively, with grade 1 and grade 2 adverse reactions. Conclusions:Risk factors for radiation pneumonia in elderly patients with esophageal cancer after imRT include tumor location, diabetes, V5, V10, V15, V20, MLD, concurrent chemotherapy, reradiotherapy and chronic obstructive pulmonary disease.

Construction of a comprehensive nutritional index and relationship with quality of life and survival in patients with nasopharyngeal carcinoma undergoing intensity-modulated radiation therapy / 中国实用护理杂志

Objective:To construct a comprehensive nutritional index after treatment of nasopharyngeal carcinoma patients with intensity-modulated radiation therapy (IMRT), and to analyze its relationship with quality of life and 3-year survival period, and aimed to provide some reference for the management of nasopharyngeal carcinoma patients.Methods:This was a prospective cohort study. The clinical data of 431 nasopharyngeal carcinoma patients who admitted to Beijing Tongren Hospital Affiliated to Capital Medical University from January 2017 to December 2021 were collected using convenience sampling method. To evaluate the nutritional status of the patients, the BMI, change in body weight, hemoglobin, lymphocyte count, and albumin level and other clinical data of the patients were collected before and after intensity-modulated radiation therapy. The comprehensive nutrition index after IMRT was constructed by principal component analysis. The Chinese version of European Organization for Reasearch and Treatment of Cancer quality of life questionnare-Core 30 (EORTC QLQ-C30) and Quality of life questionnaire head and neck cancer module(QLQ-H&N35) were used to evaluate the patients′ quality of life. The best diagnostic cutoff point for predicting patient death within 3 years using ROC, and based on the determined optimal diagnostic cutoff point, all patients were divided into a low comprehensive nutritional index group and a high comprehensive nutritional index group. And analyzed the Pearson correlation between comprehensive nutritional index and quality of life.Differences in 3-year survival between the two groups were compared using the Kaplan-Meier method and Log-rank test.Results:Using the diagnostic threshold of receiver operating characteristic, all patients were divided into low comprehensive nutrition index group ( n=280) and high comprehensive nutrition index group ( n=151).The BMI, percentage of weight change, albumin, hemoglobin, and lymphocyte count of nasopharyngeal carcinoma patients before intensity-modulated radiation therapy were (23.14 ± 2.87) kg/m 2, (1.08 ± 0.14)%, (44.02 ± 4.52) g/L, (147.28 ± 15.57)g/L, (1.76 ± 0.56)×10 9/L, and higher than after intensity-modulated radiation therapy (21.14 ± 4.07) kg/m 2, (0.97 ± 0.16)%, ( 38.99 ± 5.12) g/L, (113.87 ± 18.24)g/L, (0.50 ± 0.18)×10 9/L, respectively, the difference were statistically significant ( t values were 8.34 to 44.47, all P<0.05).The comprehensive nutritional index constructed using principal component analysis was correlated with multiple dimensions of EORTC QLQ-C30) and QLQ-H&N35, with statistically significant differences ( r values were -0.169 - 0.245, all P<0.05). Kaplan-Meier curves indicated that the 3-year survival rate of the high comprehensive nutritional index group was higher than that of the low comprehensive nutritional index group, with 87.42% and 79.29% respectively, and the difference was statistically significant ( χ2=4.53, P<0.05). Conclusions:The constructed comprehensive nutritional index could reflect the comprehensive nutritional status of nasopharyngeal carcinoma patients. Nasopharyngeal carcinoma patients with a low comprehensive nutritional index score had a worse quality of life and shorter 3-year survival. Active intervention and improvement of malnutrition in nasopharyngeal carcinoma patients should be undertaken to improve patient quality of life and improve survival.

Dosimetric Impact of Titanium Alloy Implant in Spinal IMRT Plan / 中国医疗器械杂志

The purpose of this study is to establish and apply a correction method for titanium alloy implant in spinal IMRT plan, a corrected CT-density table was revised from normal CT-density table to include the density of titanium alloy implant. Dose distribution after and before correction were calculated and compared to evaluate the dose deviation. Plans were also copied to a spinal cancer simulation phantom. A titanium alloy fixation system for spine was implanted in this phantom. Plans were recalculated and compared with the measurement result. The result of this study shows that the max dose of spinal cord showed significant difference after correction, and the deviation between calculation results and measurement results was reduced after correction. The method for expanding the range CT-density table, which means that the density of titanium alloy was included, can reduce the error in calculation.

Dosimetric comparison of heart dose with 3DCRT vs IMRT in post-mastectomy left sided chest wall irradiation

Purpose: Data regarding the efficacy of various radiotherapy techniques for post mastectomy chest-wall radiotherapy (PMRT) using hypofractionation is scarce and cardiac toxicity remains a concern. This study aims to compare effect of IMRT (Intensity Modulated Radiation Therapy) and 3D-CRT (3-Dimensional Conformal Radiation Therapy) techniques on cardiac dose. Materials and Methods: In this retrospective study, we compared IMRT and 3DCRT plans of 20 patients who received PMRT to a dose of 42.56Gy/16# and the dosimetric parameters in terms of planning target volume (PTV) coverage and dose to organ at risk (OARs) including heart and ipsilateral lung were recorded and analyzed. Result: PTV coverage were comparable with both techniques. IMRT planning provided a better conformity index as compared with 3DCRT (0.95 vs 0.91, p<0.001). The mean dose to the heart significantly reduced with IMRT (4.36Gy vs 8.2Gy, p<0.00001). Conclusion: IMRT offers a significant reduction in mean heart dose than 3DCRT in patients treated with hypofractionated post-mastectomy irradiation.