SRIM-based analysis of distribution features of Bragg peak of carbon ion radiotherapy / 中国辐射卫生

@#<b>Objective</b> To analyze the distribution features of the Bragg peak of carbon ion beams in materials using SRIM software, and to explore the use of computed tomography (CT) number to calculate the incident energy of carbon ion beams. <b>Methods</b> SRIM software was used to study the travel of carbon ion beams (100 to 300 MeV/u) in different equivalent materials, and analyze the effects of the incident energy of carbon ion beams and the type and thickness of equivalent materials on the depth of the Bragg peak of carbon ion beams. Origin 2017 was used to analyze the functional relationship between CT number and water-equivalent Bragg peak depth ratio (<i>Di</i>) through data fitting. <b>Results</b> The ratios of the Bragg peak depths in equivalent materials to that in water almost stayed constant with the increase in the incident energy of carbon ion beams. Through the functional relation between CT number and <i>D</i>_<i>i</i>, the Bragg peak depth of a carbon ion beam of a given energy in an equivalent material could be converted to the equivalent Bragg peak depth in water. <b>Conclusion</b> With the water-equivalent Bragg peak depth ratio <i>D</i>_<i>i</i> and CT number of different volume units of human tissues, the equivalent Bragg peak depth in water required for the Bragg peak to fall in the tumor can be accurately calculated, which can be used to reversely infer the needed incident energy of carbon ion beams.

Advances on the technique of three-dimensional intracavitary brachytherapy for cervical cancer / 中国辐射卫生

Cervical cancer is a common female reproductive system malignant in developing countries. Radiotherapy plays a very important role in the treatment of cervical cancer, and brachytherapy is an essential part of cervical cancer radiotherapy. With the rapid development of CT and MRI imaging technology, brachytherapy cervical cancer has gradually developed from the traditional two-dimensional image-guided technology to three-dimensional image-guided technology. There are more and more treatment methods, including intracavitary brachytherapy, interstitial brachytherapy and intracavitary/interstitial brachytherapy. This paper reviews several common techniques of three-dimensional brachytherapy for cervical cancer, and discusses the dosimetric feasibility of internal and external integration irradiation.

Application of inverse planning simulated annealing in the treatment of cervical cancer with combined intracavitary and interstitial three-dimensional brachytherapy / 中华放射医学与防护杂志

Objective To evaluate the effect of an inverse planning simulated annealing (IPSA) in the treatment of cervical cancer with combined intracavitary and interstitial three-dimensional brachytherapy.Methods A total of 60 patients with locally advanced cervical cancer who received both external beam radiotherapy and combined intracavitary and interstitial brachytherapy in our hospital from October 2016 to July 2018 were enrolled.Patients were divided into four groups with 15 patients each according to the number of needles applied (1,2,3,and 4 needles,respectively).Dosimetric distributions were optimized with both Graphical optimization (GRO) and IPSA.Paired t-test was applied to compare the dosimetric differences between plans optimized with GRO and IPSA.Results The Dg0 and V100 of IPSA plans were higher than those of GRO (t=-4.742,-4.823,P＜0.05),while the conformity index (CI) and conformal index (COIN) were slightly lower than those of GRO plans (t=9.642,8.783,P＜0.05).No significant difference in the V150,V200,V300 between IPSA and GRO (P＞0.05) was observed.There was also no significant difference in the D2cm3 of bladder and rectum between IPSA and GRO (P＞0.05).The difference of Dg0 between IPSA and GRO was increased as the number of implanted needles increased,which increased from 4 cGy to 14 cGy as the number of needle increased from 1 to 4.The difference of V100 between GRO and IPSA was also increased as the number of needle increased.Conclusions In the treatment of cervical cancer with combined intracavitary and interstitial threedimensional brachytherapy,IPSA plan could improve the target coverage(D90,V100)without increasing the dose to the OARs and high dose region in the target compared with GRO.With the numbers of needles increased,the advantage of IPSA increased in terms of target coverage.

Introduction of relevant criteria for quality assurance and quality control of tumor radiotherapy at home and abroad / 中华放射肿瘤学杂志

Multiple institutions at home and abroad have established and issued the standards,guidelines,criteria or reports of the quality assurance (QA) and quality control (QC) of radiotherapy.At present,no institutions in China have implemented systematic classification of QA-and QC-related criteria of radiotherapy.Complete standard system of QA and QC of radiotherapy should consist of clinical and physical technologies.Physical technology includes equipment,technological flow and radiation protection.The QA and QC of physical technology play a pivotal role in tumor radiotherapy.This paper introduces relevant criteria of QA and QC of radiotherapy at home and abroad.

Effect of independent breath-holding technology on target geometry in radiotherapy for liver cancer / 中华放射肿瘤学杂志

Objective To use the fusion image of the end-inhalation holding (EIH) phase and endexhalation holding (EEH) phase to define the target volume of individual patient with liver cancer,and to evaluate the target geometry,feasibility,and clinical significance of the technology.Methods Eighteen patients with liver caucer who were treated in our hospital from 2012 to 2013 were enrolled as subjects.With the same posture and scan range,all patients underwent contrast-enhanced three-dimensional computed tomography (3DCT) scans in the phases of free breathing (FB),EIH,and EEH.Gross tumor volume (GTV),clinical target volume (CTV),and organ of risk (OAR) were delineated on the above images.CTVFB was defined as GTV on the FB phase image (GTVFB) plus a margin of 10 mm,while planning target volume (PTVFB) was defined as CTVFB plus a margin of 10 mm in the right-left and anterior-posterior directions and a margin of 20 mm in the superior-inferior direction.GTVEI and GTVEE were defined as GTV on the EIH and EEH images,respectively.Based on the EEH images,the registered EEH and EIH images were fused to form GTVEI+EI.CTVEI+EE was defined as GTVEI+EI plus a margin of 10 mm,while PTVEI+EE was defined as CTVEI+EE plus a margin of 5 mm in the right-left and anterior-posterior directions and a margin of 10 mm in the superior-inferior direction.The Pinnacle3 v8.0m treatment planning system was used to design two 3D conformal radiotherapy plans for each patient.The volume,degree of inclusion (DI),matching index (MI),and central displacement of CTVFB and CTVEI+EE,as well as PTVFB and PTVEI+EE,were compared between the two plans.Results In the 18 patients,the mean CTVFB was significantly smaller than the mean CTVEI+EE(149.00±87.54 cm3 vs.188.17± 125.72 cm3,P=0.014);there was no significant difference between the mean PTVFB and PTVEI+EE (276.68± 146.41 cm3 vs.253.66± 117.35 cm3,P=0.080).DI of CTVFB to CTVEI+EF,PTVFB to PTVEI+EE,CTVEI+EE to CTVFB,and PTVEI+EE to PTVFB were (99.83±0.09)％,(84.55±8.45) ％,(80.83± 12.31) ％,and (99.78±0.08) ％,respectively.MI of CTVEI+EE to CTVFB and PTVEI+EE to PTVFB were 0.83± 0.07 and 0.87± 0.03,respectively.The central displacements of CTVEI+EE from CTVFB in x,y,and z axes were 0.55± 1.07 cm,0.76±3.02 cm,and-0.26± 1.98 cm,respectively (P =0.432,0.971,0.587).Conclusions In the treatment of liver cancer,the target volume delineation and image fusion using 3DCT images in EIH and EEH phases may avoid target omission due to respiratory movement,making it possible to increase radiation dose to target volume and improve the efficacy of radiotherapy.

Investigation on development status of radiotherapy in Guangxi Zhuang autonomous region / 中华放射医学与防护杂志

Objective To investigate the development status of tumor radiotherapy in Guangxi Zhuang autonomous region in order to provide reference for the decision-making of the competent administrative departments for public health.Methods A questionnaire survey was conducted by the aid of on-site inspection and telephone or Email investigation among the medical institutions in Guangxi to know the current status of radiotherapy units and settings,human resources,allocation of radiotherapy facilities,and standardization of medical practices.Results Up to the end of August 2014,radiotherapy was carried out in 39 hospitals,with other 5 hospitals under preparation for construction.Among these 40 hospitals were three-dimensional conformal radiotherapy in 38,intensity modulated radiation therapy (IMRT) in 23,and image guided radiation therapy (IGRT) in 5.There were 48 linear accelerators,15 afterloading therapy apparatus,and 4 γ-knife or X-knife in Guangxi.There were 647 professional personnel (except nurses),including 322 radiation oncologists,100 radiotherapy physicists,213 radiotherapy technologists and 12 professional engineers.There were 2 000 to 2 500 hospital beds and 20 000 cancer patients had received radiotherapy in 2013.1 600 to 2 000 people received treatment on average every day.Conclusions The present radiotherapy resources in Guangxi are insufficient and the input to radiotherapy equipment is deficient,with low proportion of cancer patients treated with radiotherapy.Because of the uneven radiotherapy quality among different hospitals,the reasonable planned development and unified diagnostic and treatment practices are required to improve radiotherapy level in Guangxi.For shortage of medical staff and high-quality physical and technical personnel,the improvements are needed by fostering and introduction of personnel.Compared with developed regions in China,the introduction of new technology is largely needed.

The effect of carbon fiber couch on dose distribution of conformal intensity modulated plan / 中华放射肿瘤学杂志

Objective To evaluate the effect of carbon fiber couch on dose distribution of radiotherapy planning and verification pass rate.Methods Establishing the carbon fiber treatment couch model in Pinnacle8.0m Treatment Planning system (TPS),and then this model was used to correct dose calculations of oblique fields in the treatment plans of 10 cases of nasopharyngeal carcinoma,10 cases of breast cancer and 10 cases of lung cancer and evaluate the effect of carbon fiber couch on the whole dose distribution of the plans.Then these plans were measured by three-dimensional dose verification equipment Delta4 to confirm the improvement extent of Gamma pass rate after considering the carbon fiber treatment couch.Results For the majority of plans,when the carbon fiber couch was taken into consideration,the target doses was significantly reduced (4772 cGy-7266 cGy vs.4859 cGy-7347 cGy,P=0.000-0.002) and the relative deviation of D95 was 1％ to 3％.Measurement results of Delta4 showed that Gamma pass rate (3 mm/3％ criteria) increased in all plans (96.4％-98.8％ vs.93.4％-97.3％,P =0.000),some of that were up to 5 percentage when the couch model was applied.Conclusions Target doses will be overestimated if the treatment couch is ignored in TPS measurement.,However it should arouse enough attention when the disease with smaller doses corresponding gradient.

Potential of adaptive radiotherapy to escalate the radiation dose for non-small cell lung cancer / 中国肿瘤临床

Objective: To evaluate the potential dose influence to organs at risk (OARs) and targets of adaptive radiotherapy (ART) for non-small cell lung cancer (NSCLC). Methods:Twice positional CT images of 12 patients with locally advanced NSCLC were captured during radio-(n=3) or radio-chemotherapy (n=9) for ART simulation. The twice positional scanningplan was fused using MIM software. The variation of irradiation doses for the lung, heart, and spinal cord was evaluated, and the prescription doses for the targets were escalated. Results:Adaptive radiation enabled dose reduction by an average of 3.53%for lung V20 and by 2.55%for V30. The mean dose for the lung decreased by 2.11 Gy. The dose was reduced by an average of 4.17%for heart V30 and by 3.37%for V40. Meanwhile, the maximum dose for the spinal cord was reduced by 3.52 Gy on average. Lung sparing with ART enabled an iso-mean lung dose escalation of the Planning gross tumor target volume dose, which improved by an average of 1.25 Gy. Conclusion:The adap-tation of radiotherapy for continuous tumor shrinkage during the treatment course for NSCLC reduces doses to OARs, enables signifi-cant dose escalation, and has the potential to increase local control.

CT-MR image fusion in the delineation of gross target volume for nasopharyngeal carcinoma / 中华放射肿瘤学杂志

Objective To compare the accuracy and feasibility among CT, MR, and CT-MR image fusion technology in the delineation of gross target volume (GTV) for nasopharyngeal carcinoma (NPC). Methods Thirty-six consecutive patients with newly diagnosed or recurrent NPC were enrolled. Each pa-tient underwent both CT and MR scanning in the same treatment position. Several lead marks were made at the exactly same locations of the body surface before CT and MR scanning. The two sets of images were then transferred to the Tomcon workstation for image fusion. CT-MR image registration was performed using Land-Mark methods. GTV of each patient was contoured on CT (GTV_(CT)), MR (GTV_(MR)) and CT-MR (GTV_(CT-MR)) images. Results The mean GTV_(CT), GTV_(MR) and GTV_(CT-MR) were 27.60 cm~3, 30.99 cm~3 and 31.71 cm~3, respectively (F = 7.48, P = 0.001). Significant difference was found between GTV_(CT) and GTV_(MR) (q =2.54,P=0.016), GTV_(CT) and GTV_(CT-MR) (q =3.10,P =0.004), but not GTV_(MR) and GTV_(CT-MR) (q = 1.31 ,P = 0. 199). Significant difference among GTV_(CT), GTV_(MR) and GTV_(CT-MR) was found in patients with skull base invasion (35.65, 42.70 and 44.22 cm~3 ; F = 14. 13, P = 0. 000), but not in those without skull base invasion (20.79 cm~3, 20.46 cm~3 and 21.18 cm~3 ; F = 0.18, P = 0.832). Significant difference between GTV_(CT) and GTV_(CT-MR) was found in patients with T_3 and T_4 tumor (t = -2.17,P =0. 036), but not in those with T_1 and T_2 (t = -0.66 ,P = 0.514). Conclusions CT-MR image fusion is helpful in GTV de-lineation for NPC, particularly for patients with skull base invasion.

Therapeutic efficacy of tumor-derived heat shock protein 70 immunotherapy combining interleukin-2 on tumor-bearing mice / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the therapeutic efficacy of compound immunotherapy of tumor-derived heat shock protein 70 (HSP70) and interleukin-2 (IL-2) on tumor-bearing mice, and to provide reference for translating this strategy to human cancer.</p><p><b>METHODS</b>Cell culture, techniques for protein extraction and purification, SDS-PAGE, Western blot and capillary electrophoresis for HSP70 detection and purity analysis, and animal experiments were used. Mice were treated with HSP70 5 or 10 microg and IL-2 50 kU, 100 kU or 2 kU (maintaining dosage) at previously designated intervals.</p><p><b>RESULTS</b>Both the mono-administration of either HSP70 or IL-2 and the compound immunotherapy of HSP70 and IL-2 obviously inhibited the growth of the implanted tumor and prolonged the life span of the mice to different extents. However, long periods of tumor-free survival (over 90 days) were demonstrated only in HSP70 10 micro g group, HSP70 10 microg-IL-2 50 kU group, and HSP70 10 microg-IL-2 100 kU group (40%, 40%, 60% respectively). On the other hand, none of the mice in the rest groups achieved long-term survival. Statistical significance was apparent in comparison with the groups without long period survival (P < 0.025 - 0.05).</p><p><b>CONCLUSION</b>Our research revealed that tumor-derived HSP70 immunotherapy was much more effective than IL-2 alone. And in compound immunotherapy, HSP70 was the main factor in delaying or eradicating the tumors. The proper combination of HSP70 and IL-2 (10 microg HSP70 and 100 kU IL-2 in this experimental mouse model) clearly enhanced the immunotherapy efficacy which indicated that the specific immunotherapy as a main part of tumor immunotherapy assisted by cytokine immunotherapy would be a promising strategy in cancer treatment.</p>

Study on the anti-tumor efficacy induced by heat shock protein 70-peptide complexes derived from tumor cells / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To study the efficacy and explore the mechanism of the anti-tumor immunity elicited by heat shock protein 70-peptide complexes (HSP70-PC) derived from tumor cells.</p><p><b>METHODS</b>Cells culture, flow cytometric analysis, affinity chromatography for protein purification, SDS-PAGE, Western-blotting and animal experiment were used.</p><p><b>RESULTS</b>HSP70-PC immunization rendered protective effect to both naive tumorl-bearing mice. All of the naive mice obtained complete resistance to Hcaf cell attack; 40% of the tumor-bearing mice survived for over 90 days, whereas the mice of control group died within 2 weeks (P < 0.01). CD8+ subset of T lymphocytes in the peripheral blood of immunized mice increased by 12%.</p><p><b>CONCLUSION</b>HSP70-PC induces anti-tumor immunity via activation of cytotoxic T lymphocytes (CTLs), and it possesses strong tumor vaccine effect. Our research adds more evidence to support the clinical use of HSP70-PC to fight human cancers.</p>

The Influence of Tumor-Derived Heat Shock Protein 70 on the Expression of Thl Type Cytokines of Tumor-Bearing Mice / 中国肿瘤生物治疗杂志

Objective: To investigate the successive fluctuation of some Thl type cytokines in the peripheral blood of tumor-bearing mice treated with tumor-derived heat shock protein 70 ( HSP70) , explore the mechanism of HSP 70 in breaking through the tumor-immunity tolerance of the organism with tumor-burden and in inducing effective anti-tumor immune response, and provide valuable reference for tumor-derived HSP70 administration in treating human cancer. Methods : Cell culture, techniques for protein extraction and purification, SDS-PAGE, Western-blot, capillary electrophoresis, ELISA technique and animal experiment were applied. Results: HSP70 could result in apparent tumor-inhibitory effect and upregulate some Thl type cytokines(IL-2, TNF-?, and IFN-?) in the peripheral blood of the treated mice gradually to the frequency of HSP70 administration, and showed no reduction trend in two weeks after the final treatment. Statistically significant difference was observed contrasted with those of the control group (P

Study on the anti-tumor immune efficacy of tumor-derived heat shock protein70 / 中国免疫学杂志

90 days),obvious difference( P