CT based automatic clinical target volume delineation using a dense-fully connected convolution network for cervical Cancer radiation therapy.

Background: It is very important to accurately delineate the CTV on the patient's three-dimensional CT image in the radiotherapy process. Limited to the scarcity of clinical samples and the difficulty of automatic delineation, the research of automatic delineation of cervical cancer CTV based on CT images for new patients is slow. This study aimed to assess the value of Dense-Fully Connected Convolution Network (Dense V-Net) in predicting Clinical Target Volume (CTV) pre-delineation in cervical cancer patients for radiotherapy.

[Automated Pre-delineation of CTV in Patients with Cervical Cancer Using Dense V-Net].

We use a dense and fully connected convolutional network with good feature learning in small samples, to automatically pre-deline CTV of cervical cancer patients based on CT images and evaluate the effect. The CT data of stage IB and IIA postoperative cervical cancer with similar delineation scope were selected to be used to evaluate the pre-sketching accuracy from three aspects:sketching similarity, sketching offset and sketching volume difference. It has been proved that the 8 most representative parameters are superior to those with single network and reported internationally before.

GSTP1 Ile105Val polymorphism might be associated with the risk of radiation pneumonitis among lung cancer patients in Chinese population: A prospective study.

Growing data suggest that DNA damage repair and detoxification pathways play crucial roles in radiation-induced toxicities. To determine whether common functional single-nucleotide polymorphisms (SNPs) in candidate genes from these pathways can be used as predictors of radiation pneumonitis (RP), we conducted a prospective study to evaluate the associations between functional SNPs and risk of RP. We recruited a total of 149 lung cancer patients who had received intensity modulated radiation therapy (IMRT).

Association of DNA repair gene polymorphisms with the risk of radiation pneumonitis in lung cancer patients.

A total of 149 lung cancer patients were recruited to receive intensity modulated radiation therapy (IMRT). The association of developing radiation pneumonitis (RP) with genetic polymorphism was evaluated. The risks of four polymorphic sites in three DNA repair related genes (ERCC1, rs116615:T354C and rs3212986:C1516A; ERCC2, rs13181:A2251C; XRCC1, rs25487:A1196G) for developing grade ≥ 2 RP were assessed respectively.

[Accuracy of Dose Calculation with CBCT Images under Different Scanning Conditions].

The treatment plans were designed based on planning CT of Catphan phantom's homogenic and heterogenetical module, respectively. With the OBI system, Catphan phantom was scanned under different scanning conditions. The dose was recalculated by applying treatment plans based on planning CT to the CBCT images with its individual hounsfield unit-electron density calibration curve.

[Results of Five-year Quality Control Program and the Change of QA Mode for Helical Tomotherapy Machine].

Helical tomotherapy (HT), as a new IMRT technology, utilizes a fan beam of radiation for treatment. It combines the main characteristics of a modern CT scanner and a linear accelerator to achieve the function of helical tomotherapy. Due to the complexity of the system with a highly integrated and automated features, monitoring its operation, continuing to improve the stability and reliability, and simplifying its quality control procedures has become an important part of quality assurance (QA) for HT.

[RapidArc Delivery Performance Using EDR2 Film and EPID Measurement].

This study describes the development and implementation of EDR2 film and electronic portal imaging device (EPID) during RapidArc QA. The tests were designed to evaluate RapidArc performance using EDR2 film and EPID tools. The accuracy of MLC position during gantry rotation, the ability to vary and control the dose-rate and gantry speed, the synchronization of variable MLC speed and dose-rate were examined.

[Evaluation of the EDOSE for IMRT Delivery Quality Assurance].

Objective: Evaluation of intensity-modulated radiation therapy(IMRT) delivery quality assurance(DQA) using EDOSE software based on accelerator electronic portal imaging device (EPID).

Methods: Analysed the dose response uniformity correction of EPID imaging plate in different fields and the gamma pass rates about the fields; And compared the calculated parameters of the EDOSE and the Pinnacle planning station.

Results: The uniformities on the homogeneous region of thefi elds are good after who corrected by EDOSE.

[Evaluation of Cone Beam CT Image Quality and Analysis of Its Long-term Stability on HU Values under Different Conditions].

Objective: To evaluate the cone beam CT (CBCT) image quality and its long-term stability for HUs under different scanning conditions.

Methods: With the OBI system, Catphan 504 phantom using the different modes was scanned through one year. Analysis of variance (ANOVA) was used to evaluate the CBCT images.

Dose Evaluation of Fractionated Schema and Distance From Tumor to Spinal Cord for Spinal SBRT with Simultaneous Integrated Boost: A Preliminary Study.

BACKGROUND This study investigated and quantified the dosimetric impact of the distance from the tumor to the spinal cord and fractionation schemes for patients who received stereotactic body radiation therapy (SBRT) and hypofractionated simultaneous integrated boost (HF-SIB). MATERIAL AND METHODS Six modified planning target volumes (PTVs) for 5 patients with spinal metastases were created by artificial uniform extension in the region of PTV adjacent spinal cord with a specified minimum tumor to cord distance (0-5 mm). The prescription dose (biologic equivalent dose, BED) was 70 Gy in different fractionation schemes (1, 3, 5, and 10 fractions).

Dosimetric evaluation of 4 different treatment modalities for curative-intent stereotactic body radiation therapy for isolated thoracic spinal metastases.

To investigate the dosimetric characteristics of 4 SBRT-capable dose delivery systems, CyberKnife (CK), Helical TomoTherapy (HT), Volumetric Modulated Arc Therapy (VMAT) by Varian RapidArc (RA), and segmental step-and-shoot intensity-modulated radiation therapy (IMRT) by Elekta, on isolated thoracic spinal lesions. CK, HT, RA, and IMRT planning were performed simultaneously for 10 randomly selected patients with 6 body types and 6 body + pedicle types with isolated thoracic lesions. The prescription was set with curative intent and dose of either 33Gy in 3 fractions (3F) or 40Gy in 5F to cover at least 90% of the planning target volume (PTV), correspondingly.

[The Dose Effect of Isocenter Selection during IMRT Dose Verification with the 2D Chamber Array].

To investigate the dose effect of isocenter difference during IMRT dose verification with the 2D chamber array. The samples collected from 10 patients were respectively designed for IMRT plans, the isocenter of which was independently defined as P(o), P(x) and P(y). P(o) was fixed on the target center and the other points shifted 8cm from the target center in the orientation of x/y.

[Patient-specific dose verification method using ArcCHECK for total marrow irradiation with intensity modulated arc therapy].

To investigate the patient-specific dose verification method using ArcCHECK for total marrow irradiation (TMI) with Volumetric Modulated Arc Therapy (VMAT) and Helical Tomotherapy (HT). The kVCT images collected from 8 patients were respectively designed for RapidArc and Tomotherapy plans in total marrow irradiation. ArcCHECK was used for dose verification for the head-neck, chest-abdomen and pelvic.