[en] The technique of fusing different imaging modalities is currently being investigated in radiotherapy treatment planning, especially in accurate radiotherapy. It has a significant impact in the modern era of accurate radiotherapy. It makes a clear distinction of tumor and modifies the false positive or false negative lesions found by single imaging modality and minimizes the variation of the target volumes contoured by different oncologists

[en] Objective: To evaluate the effect of late-course hypofractionated stereotactic radiotherapy (LCHSRT) on locally advanced non-small cell lung cancer. Methods: From October 1997 to June 1999, 106 patients with locally advanced non-small cell lung cancer were randomized into conventional radiotherapy group (CRT) and LCHSRT group. Ninety-one patients with complete data were analyzed including 43 patients in CRT group and 48 patients in LCHSRT group. In CRT group, 18 patients were staged IIIa and 25 IIIb; whereas 19 patients were staged IIIa and 29 IIIb in LCHSRT group. The initial median dose of 43.5 Gy was given in CRT group to the primary tumor, ipsilateral hilum and mediastinum using AP-PA fields with 1.8-2.0 Gy per fraction, then 21.7 Gy was boosted to the residual primary and metastatic regional lymph nodes to the median total dose of 65.2 Gy. In LCHSRT group, after the first 44.4 Gy to the primary tumor, ipsilateral hilar region and mediastinum by AP-PA fields with a dose fraction of 1.8-2.0 Gy, noncoplanar arc hypofractionated stereotactic radiotherapy was delivered to the residual primary and metastatic lymph nodes to the total dose of (22.8 ± 5.5) Gy with 4-7 Gy per fraction treated every other day. Results: The radiation pneumonitis rates were 11.6% and 14.6% in CRT group and LCHSRT group, respectively. The radiation pulmonary fibrosis rates diagnosed by CT scan 6 months after radiotherapy were 48.8% and 66.7% in CRT group and LCHSRT group, respectively. The complete regression (CR) rates evaluated by CT scan 3 months after treatment in CRT and LCHSRT group were 30.2% and 63.5%, respectively (P<0.01). The 1-year local tumor control rates and the 1-year survival rates in CRT and LCHSRT group were 62%, 86.5% (P=0.054) and 55.8%, 79.2% (P<0.05), respectively. However, there was no statistical difference in 2-year survival between the two groups. Conclusions: Late-course hypofractionated stereotactic radiotherapy is a way to escalate the radiation dose to locally advanced non-small cell lung cancer. (and others)

[en] Objective: To investigate the impact of PET/CT on clinical staging of non-small cell lung cancer (NSCLC), delineation of target volume, and prediction to alleviate radiation pneumonitis (RP) from 3-dimentional conformal radiotherapy (3D-CRT) planning. Methods: From October 2002 to June 2004, 34 patients diagnosed cytologically or pathologically with NSCLC, who were candidates for radical radiotherapy or surgery, received PET/CT scanning. Both images were transmitted into treatment planning system (TPS) workstations respectively and were fused and reconstructed. All patients were staged according to the 1997 World Health Organization (WHO) staging system. The impact of PET/CT on the clinical staging of all the patients was determined. The gross tumor volume (GTV) was delineated on the CT imaging and PET/CTfused imaging respectively. Based on the two images, 3D- CRT planning was made respectively at the TPS workstation with Topslane software, the planning target volumes (PTV) being defined with a 15 mm margin around GTV of primary lumps (PTV₁) and 7 mm for involved lymph nodes (PTV₂). Evaluating indexes including V_PTV (volume of PTV, V_PTV = V_PTV1 + V_PTV2), V₂₀ (percentage of the total lung volume receiving more than 20 Gy), MLD (mean lung dose) , TCP (tumor control probability) , NTCP (normal tissue complication probability) , and Ds (dose to spinal cord) were selected to be paralleled to compare the quality of the two plans and the impact of PET/CT on RP was further analyzed. Results: In 13 of 34 (38.2%) cases, PET/CT information changed the clinical staging, 8 of which were upstaged and 5 downstaged. For 10 of 34 (29.4%) cases, PET/CT results modified their management decisions. Among 16 patients performed by surgery, 14 had consistent PET/CT staging with pathologic staging. The sensitivity of PET/CT was 93.3% and accuracy 87.5%. Difference of indexes including V_PTV, V₂₀ and MLD between the two radiation planning was statistically significant, but Ds, TCP and NTCP were not statistically different. Conclusion: PET/CT has notable impact on clinical staging, target volume delineation and hence on its 3D-CRT planning of NSCLC. In contouring the target volume, compared with CT imaging, PET/CT can decrease V_PTV, V₂₀ and MLD significantly in patients with atelectasis and obstructive pneunonitis, so can reduce the rate and severity of RP effectively and can better protect normal lung tissues. (authors)

[en] ¹⁸F-FDG PET-CT is recommended for the diagnosis and treatment of non-small cell lung cancer (NSCLC), and guiding the optimization of radiotherapy planning. The target area determined by biological information carried by functional images is defined as biological target volume (BTV). However, BTV significantly differs from the gross tumor volume (GTV) and internal target volume (ITV) defined by the International Commission on Radiation Units and Measurements (ICRU) report. It is still a challenging task to directly apply BTV to radiotherapy planning. The limitation of PET image, the accuracy of fusion with auxiliary anatomic images and the influence of respiratory movement cause the uncertainty of BTV definition in NSCLC patients. Referring to different anatomical images, multiple approaches can be employed to achieve BTV motion information compensation. Application of PET-CT in predicting the prognosis of NSCLC patients after radiotherapy and distinguishing the recurrence risk of biological sub-target contribute to achieving the dose planning for radiotherapy planning. (authors)

[en] This study was performed to explore and compare the dosimetric variance caused by respiratory movement in the breast during forward-planned intensity-modulated radiotherapy (IMRT) after breast-conserving surgery. A total of 17 enrolled patients underwent the three-dimensional computed tomography (3DCT) simulation scans followed by four-dimensional computed tomography (4DCT) simulation scans during free breathing. The treatment planning constructed using the 3DCT images was copied and applied to the end expiration (EE) and end inspiration (EI) scans and the dose distributions were calculated separately. CTV volume variance amplitude was very small (11.93±28.64 cm³), and the percentage change of CTV volumes receiving 50 Gy and 55 Gy between different scans were all less than 0.8%. There was no statistically significant difference between EI and EE scans (Z=-0.26, P=0.795). However, significant differences were found when comparing the D_mean at 3DCT planning with the EI and EE planning (P=0.010 and 0.019, respectively). The homogeneity index at EI, EE and 3D plannings were 0.139, 0.141 and 0.127, respectively, and significant differences existed between 3D and EI, and between 3D and EE (P=0.001 and 0.006, respectively). The conformal index (CI) increased significantly in 3D treatment planning (0.74±0.07) compared with the EI and EE phase plannings (P=0.005 and 0.005, respectively). The V₃₀, V₄₀, V₅₀ and D_mean of the ipsilateral lung for EE phase planning were significantly lower than for EI (P=0.001-0.042). There were no significant differences in all the dose-volume histogram (DVH) parameters for the heart among these plannings (P=0.128-0.866). The breast deformation during respiration can be disregarded in whole breast IMRT. 3D treatment planning is sufficient for whole breast forward-planned IMRT on the basis of our DVH analysis, but 4D treatment planning, breath-hold, or respiratory gate may ensure precise delivery of radiation dose. (author)

[en] Objective: To observe the radiosensitization and side-effects of irrisquinone in combination with radiotherapy in treatment of esophageal cancer. Methods: From January 1996 to August 1997, 60 cases of esophageal cancer were randomly divided into two groups--the trial group (irrisquinone plus irradiation, 30 cases) and the control group (radiotherapy alone, 30 cases). In the trial group, irrisquinone provided by Shangdong Xinhua Pharmaceutical Factory was administered at 220 mg/m²/day (110 mg/m², twice daily), in combination with radiotherapy throughout the course of treatment. Irradiation was administered with 1.25 MeV ⁶⁰Co γ-rays and/or 6MV or 15 MV X-rays, 2 Gy per day and 5 times per week. Total dose was about 60-70 Gy over 6-7 weeks, and the median doses to the trial group and the control group were 66.1 Gy and 68.6 Gy, respectively. Results: At the end of treatment course, complete remission rate (CR) in the trial group was 53.33% whereas that in the control group was 26.67% (P < 0.05), and three months later, the Cr were 73.33% and 46.67%, respectively. Sensitization ratios of irrisquinone were 1.68 and 1.27 by the partial remission at doses of 40 Gy and 60 Gy. The acute toxicity of irrisquinone were diarrhea, nausea and vomiting. The diarrhea rate was 56.6% in the trial group which was higher than that in the control group, but it was generally not severe and the patients were adapted to it soon without interruption of its administration. Conclusion: irrisquinone in combination with radiotherapy in treatment of esophageal cancer can increase the complete remission rate at the end of treatment course

[en] This paper proposes an incentive simultaneous wireless information and power transfer (SWIPT) scheme for cognitive radio networks, wherein the secondary user (SU) provides wireless power transfer for the primary user (PU) in the exchange for partial bandwidth of the latter. To enable the proposed scheme, both the secondary transmitter (ST) and the primary receiver (PR) are equipped with multiple antennas. Specifically, SU helps to charge PU via adjusting its beamforming vector and PR harvests energy with a subset of its antennas; as a reward, PU allocates part of its bandwidth to SU. Our goal is to jointly optimize the beamforming vector of SU, the bandwidth allocation and covariance matrix of PU, such that the transmission rate of SU is maximized and meanwhile PU’s requirements in transmission rate and energy are satisfied. This optimization problem is non-convex. To handle this non-convex problem, we decompose it into two independent subproblems. One is to optimize the covariance matrix, the other is to optimize the beamforming vector of SU as well as the bandwidth allocation of PU, which is divided into a two-layer optimization problem. In the inner subproblem, we obtain the optimal beamforming vector for any given fixed bandwidth allocation, while in the outer subproblem we propose a gradient based algorithm and obtain the optimum bandwidth allocation. Numerical results are given to show the achievable system performance with varying parameters and also the convergence of the proposed algorithm. (paper)

[en] Objective: To measure the displacement of solitary pulmonary lesion (SPL) using four-dimensional CT (4DCT), and to compare the planning target volume using 4D maximum intensity projection (MIPMIP) (PTV4D_MIP) with the empirical PTV3D. Methods: Data were acquired from 24 consecutive patients with SPL. For each patient, respiration-synchronized 4DCT images and standard axial CT scans were obtained during free breathing. In lung window setting, the 4D technique was used to measure the displacement of SPL in three dimensions. We compared an PTV created using the MIP (PTV4D_MIP) to the PTV created from the gross tumor volume (GTV) enlarged isotropically for each spatial direction by 1.0 cm and 1. 5 cm in the PTV3D_1.0cm and PTV3D_1.5cm. Results: The SPL located in the lower lobe showed significant difference with the upper and middle lobe in y axis (0. 44 cm, 0.92 cm, t =2.87, P =0.000),but there was no difference in both x and z axis (0.27 cm, 0.39 cm, t =1.44, P =0.116 and 0.29 cm, 0.40 cm, t =1.51, P =0.227). SPL showed significantly greater displacement in y axis than in both x and z axis [0.60 cm and 0.31 cm (t =4.23, P=0.000), 0.60 cm and 0.32 cm (t =4.65, P=0. 000)], but there was no significant difference between x and z axis (0.31 cm, 0.32 cm, t =0.33, P =0.741). There was no statistically difference between the peripheral lung cancer and the pulmonary metastasis tumor in three directions (x axis : 0.37 cm, 0.32 cm, t =0.52, P =0.223; y axis : 0.54 cm, 0.95 cm, t =- 1.38, P =0.061; z axis: 0.42 cm, 0.37 cm, t=0.29, P=0.859). Both PTV3D_1.0cm and PTV3D_1.5cm showed significantly greater volume than PTV4D_MIP (46.73 cm³, 86.52 cm³ and 30.02 cm³, t =-11.35, -12.09, P =0.000, 0.000). Conclusions: The displacement of SPL in y axis is much greater than x and z axis. The empirical PTV3D is much bigger than PTV4D_MIP, which suggests that 4D_MIP provide adequate coverage of the moving target and minimize dose to normal tissues. (authors)

[en] Aimed at the rate of flow in the drawing and injection well is not stable, the problem perplex the normal operation at mining area, so, drawing and injection fluid alarm system is set up in one in-situ leaching uranium well site in Xinjiang. The original electromagnetic flowmeters, audible and visual alarms, PLC controllers, data acquisition module and Industrial Personal Computer are employed in the application of the alarm system in actual production process. Abnormal situations in production process can be monitored in the control room by on duty staff. If faults are happened, alarms are made in time. Therefore, environmental pollution events are eliminated, the safety of normal operation is ensured, labor intensity and workers are reduced, automation management is realized at the mining area. (authors)

[en] Objective: To investigate the correlations between the displacements of surgical clips, skin markers and the gross tumor volume (GTV) delineated by surgical clip and seroma based on four-dimensional computed tomography (4DCT) during normal breathing. Methods: On each of the 10 respiratory phases of 4DCT with 15 patients of breast cancer, the surgical cavity, which was defined as GTV and formed by both surgical clips and seroma, all surgical clips in the cavity, and skin markers on the skin were delineated by the same radiation oncologist. The center displacements of GTV, selected boundary surgical clips and skin markers in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions were recorded and analyzed by Pearson method. Results: In the AP direction, there was a positive correlation between the displacements of the GTV and the inner clip (r = 0.643, P = 0.013). In the SI direction, the displacement of GTV was positively correlated with those of the lower clip and the skin marker at anterior body midline (r = 0.857 and 0.643, P = 0.002 and 0.013). In the LR and AP directions, there was a positive correlation between the displacements of the outer clip and the ipsilateral skin marker (r = 0.757 and 0.697, P = 0.001 and 0.025), but they were negatively correlated with each other in the SI direction (r = -0.647, P = 0.043). In the AP direction, there was a positive correlation between the displacements of the inner clip and the skin marker at the anterior body midline (r = 0.738, P = 0.015). Conclusions: The correlations between the displacement of GTV delineated by surgical clips and seroma and the displacements of surgical slips and skin markers vary under different conditions, and so does the correlation between the displacements of surgical clips and skin markers. (authors)