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.
Radiotherapy, Intensity-Modulated/methods* ; Titanium ; Radiotherapy Dosage ; Alloys ; Radiometry/methods* ; Radiotherapy Planning, Computer-Assisted/methods*

In Vivo Dosimetry ; Radiotherapy Dosage ; Radiometry/methods* ; Electronics ; Radiotherapy, Intensity-Modulated/methods* ; Phantoms, Imaging ; Algorithms

Advanced radiotherapy technology enables the dose to more accurately conform to the tumor target area of the patient, providing accurate treatment for the patient, but the gradient of the patient's radiation dose at the tumor edge is getting larger, which putting forward higher requirements for radiotherapy dose verification. The dose verification system software KylinRay-Dose4D can verify the patient's pre-treatment plan and the in vivo/on-line dose during the patient's treatment, providing important reference for the physicist to modify the radiotherapy plan and ensuring that the patient receives accurate treatment. This study introduces the overall design and key technologies of KylinRay-Dose4D, and tests the pre-treatment plan dose checking calculation and 2D/3D dose verification through clinical cases. The test results showed that the 2D/3D gamma pass rate (3 mm/3%) of KylinRay-Dose4D reconstructed dose compared with TPS plan dose and measured dose is larger than 95%, which indicating that the reconstructed dose of KylinRay-Dose4D meets the requirement of clinical application.
Humans ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted/methods* ; Radiotherapy, Intensity-Modulated/methods* ; Software ; Neoplasms ; Phantoms, Imaging ; Radiometry/methods*

OBJECTIVE: To study the feasibility and potential benefits of beam angle optimization (BAO) to automated planning in liver cancer. METHODS: An approach of beam angle sampling is proposed to implement BAO along with the module Auto-planning in treatment planning system (TPS) Pinnacle. An in-house developed plan quality metric (PQM) is taken as the preferred evaluating method during the sampling. The process is driven automatically by in-house made Pinnacle scripts both in sampling and scoring. In addition, dosimetry analysis and physician's opinion are also performed as the supplementary and compared with the result of PQM. RESULTS: It is revealed by the numerical analysis of PQM scores that only 15% patients whose superior trials evaluated by PQM are also the initial trials. Gantry optimization can bring benefit to plan quality along with auto-planning in liver cancer. Similar results are provided by both dose comparison and physician's opinion. CONCLUSIONS It is possible to introduce a full automated approach of beam angle optimization to automated planning process. The advantages of this procedure can be observed both in numerical analysis and physician's opinion.
Humans ; Radiotherapy Planning, Computer-Assisted/methods* ; Feasibility Studies ; Radiometry/methods* ; Liver Neoplasms/radiotherapy* ; Radiotherapy, Intensity-Modulated/methods* ; Radiotherapy Dosage

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.
Humans ; Small Cell Lung Carcinoma/pathology* ; Lung Neoplasms/pathology* ; Radiotherapy, Intensity-Modulated/methods* ; Retrospective Studies ; Lung Injury ; Radiotherapy Dosage ; Radiation Injuries/epidemiology* ; Esophagitis/epidemiology* ; Risk Factors ; Pulmonary Disease, Chronic Obstructive/complications*

This article briefly describes the imaging performance standards of the kilovolt X-ray image guidance system used in radiotherapy, analyzes the main aspects that should be considered in the image quality of X-IGRT system, and focuses on parameters that should be considered in the imaging performance evaluation criteria of the CBCT X-IGRT. The purpose is to sort out the imaging performance evaluation standards of kilovolt X-IGRT system, clarify the image quality requirements of X-IGRT equipment, and reach a consensus when evaluating the imaging performance of X-IGRT system.
Radiotherapy Planning, Computer-Assisted/methods* ; Cone-Beam Computed Tomography/methods* ; Spiral Cone-Beam Computed Tomography ; Radiotherapy, Intensity-Modulated/methods* ; Radiotherapy, Image-Guided/methods*

OBJECTIVE: To investigate the influence of positioning accuracy of the multi-leaf collimators (MLC) on the passing rate of the plan dose verification for volumetric modulation arc therapy (VMAT) of cervical cancer using an Elekta linear accelerator. METHODS: The dose distributions were measured using Sun Nuclear's Mapcheck and Arccheck semiconductors matrix before and after MLC calibration in30 cervical cancer patients undergoing VMAT. Dosimetric comparisons were performed with 2D and 3D gamma passing rates of 3%, 3 mm and 2%, and 2 mm. The 3D gamma distribution was reconstructed with respect to the patient's anatomy using 3DVH software to evaluate the possible influence of MLC positioning accuracy. RESULTS: Before and after MLC calibration, the gamma passing rates of Mapcheck were (88.80±1.81)% and (99.25 ± 0.53)% under 3% and 3 mm standard, respectively, with an average increase of 10.45%. The corresponding gamma passing rates of Arccheck were (87.61±1.98)% and (98.13±0.99)%, respectively, with an average increase of 10.52%. The gamma passing rates of 3DVH were (89.87±2.28)% and (98.3±1.15)%, respectively, with an average increase of 8.43%. CONCLUSION The MLC positioning accuracy is one of the main factors influencing dosimetric accuracy of VMAT for cervical cancer. The application of Autocal software facilitates MLC calibration and improves the accuracy and safety of VMAT delivery for cervical cancer.
Female ; Humans ; Particle Accelerators ; Quality Control ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted/methods* ; Radiotherapy, Intensity-Modulated/methods* ; Uterine Cervical Neoplasms/radiotherapy*

PURPOSE: We aim to examine nasopharyngeal carcinoma (NPC) characteristics and survival outcomes in patients aged 70 years and older in the intensity-modulated radiotherapy (IMRT) era. MATERIALS AND METHODS: From 2006 to 2013, 126 non-metastatic NPC patients aged ≥ 70 years who were treated with IMRT +/‒ chemotherapy were included. Adult Comorbidity Evaluation 27 (ACE-27) was used to measure patient comorbidities. The overall survival (OS) and cancer-specific survival (CSS)were calculatedwith the Kaplan-Meier method, and differenceswere compared using the log-rank test. The Cox proportional hazards model was used to carry out multivariate analyses. RESULTS: For the entire group, only two patients (1.6%) presented stage I disease, and up to 84.1% patients had stage III-IVB disease. All patients had a comorbidity score of 0 in 24 (19.0%), 1 in 45 (35.7%), 2 in 42 (33.3%), and 3 in 15 (11.9%) patients. The main acute grade during radiotherapy was 3-4 adverse events consisting of mucositis (25.4%), bone marrow suppression (16.7%), and dermatitis (8.7%). After treatment, four patients (3.2%) developed temporal lobe injury. Five-year CSS and OS rates were 67.3% (95% confidence interval [CI], 58.6% to 77.4%) and 54.0% (95% CI, 45.6% to 63.9%), respectively. Five-year OS was significantly higher for ACE-27 score 0-1 than ACE-27 score 2-3 (72.9% and 39.9%, respectively; p < 0.001). Multivariate analyses showed ACE-27 score 0-1 was significantly associated with superior OS (hazard ratio [HR], 3.02; 95% CI, 1.64 to 5.55; p < 0.001). In addition, the rate of OS was higher for stage I-III than that of stage IV, with borderline significance (HR, 1.67; 95% CI, 0.99 to 2.82; p=0.053). But no significant advantage was observed in OS when chemotherapy was used (p > 0.05). CONCLUSION: Our findings suggest IMRT +/– chemotherapy has a manageable toxicity and provides an acceptable survival in patients aged ≥ 70 years with NPC. ACE-27 score was significantly associated with survival outcomes in this group population.
Adult ; Bone Marrow ; Comorbidity ; Dermatitis ; Drug Therapy ; Humans ; Methods ; Mucositis ; Multivariate Analysis ; Proportional Hazards Models ; Radiotherapy ; Radiotherapy, Intensity-Modulated* ; Temporal Lobe

With increasing clinical use, radiotherapy (RT) has been considered reliable and effective method for hepatocellular carcinoma (HCC) treatment, depending on extent of disease and patient characteristics. RT for HCC can improve therapeutic outcomes through excellent local control, downstaging, conversion from unresectable to resectable status, and treatments of unresectable HCCs with vessel invasion or multiple intrahepatic metastases. In addition, further development of modern RT technologies, including image-guided radiotherapy (IGRT), intensity-modulated radiotherapy (IMRT), and stereotactic body radiotherapy, has expanded the indication of RT. An essential feature of IGRT is that it allows image guidance therapy through in-room images obtained during radiation delivery. Compared with 3D-conformal RT, distinctions of IMRT are inverse treatment planning process and use of a large number of treatment fields or subfields, which provide high precision and exquisitely conformal dose distribution. These modern RT techniques allow more precise treatment by reducing inter- and intra-fractional errors resulting from daily changes and irradiated dose at surrounding normal tissues. More recently, particle therapy has been actively investigated to improve effectiveness of RT. This review discusses modern RT strategies for HCC, as well as optimal selection of RT in multimodal approach for HCC.
Carcinoma, Hepatocellular* ; Humans ; Methods ; Neoplasm Metastasis ; Radiosurgery ; Radiotherapy* ; Radiotherapy, Image-Guided ; Radiotherapy, Intensity-Modulated

To study the feasibility of ArcCheck verification system in dosimetric verification for stereotactic radiotherapy (SRT) the stereotactic radiotherapy (SRT) with flattening filter free (FFF) model.
 Methods: A total of 76 cases under SRT treatment plans were introduced into ArcCheck phantom and recalculated. Threshold criteria was set as (3%, 3 mm, 10%) or (2%, 2 mm, 10%). The calculated dose distribution and the measured dose distribution of ArcCheck phantom were compared by means of distance to agree (DTA) and Gamma analysis method respectively.
 Results: Based on the threshold criteria (3%, 3 mm, 10%), the relative and absolute mean pass rates of SRT treatment plans by DTA and Gamma analysis were greater than 95%. Based on the threshold criteria (2%, 2 mm, 10%), the relative and absolute mean pass rates of SRT treatment plan by DTA and Gamma analysis were about 90%. The dose pass rate of Gamma analysis method was slightly higher than that of DTA analysis method (P<0.001).
 Conclusion: The ArcCheck verification system is a rapid and accurate method for SRT dose verification, and discrepancies are found in different analysis methods.
Feasibility Studies ; Humans ; Phantoms, Imaging ; Radiosurgery ; methods ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; Radiotherapy, Intensity-Modulated