Intensity-modulated proton therapy(IMPT)is becoming essential for proton therapy and is under rapid development.However,for IMPT,the lateral penumbra of the spot-scanning proton beam is still an urgent issue to be sol...Intensity-modulated proton therapy(IMPT)is becoming essential for proton therapy and is under rapid development.However,for IMPT,the lateral penumbra of the spot-scanning proton beam is still an urgent issue to be solved.Patient-specific block collimators(PSBCs),which can block unnecessary doses,play a crucial role in passive scattering delivery technology but are rarely used in spot scanning.One objective of this study is to investigate the lateral penumbra variations of intensity-modulated spot scanning with and without a PSBC.For fields with varying degrees of sharpness and at varying depths in a water phantom,the lateral penumbral widths were calculated using a Monte Carlo-based dose engine from RayStation 6.The results suggest that the lateral penumbral widths can be reduced by more than 30%for uniform target volumes,regardless of whether a range-shifter is used,and that the maximum dose beyond the field edges can be reduced significantly.The results of patient cases show that the doses in organs-at-risk near the edge of the target volume decrease if a PSBC is implemented.This study demonstrates that intensity-modulated spot scanning with a PSBC can effectively reduce the lateral penumbra and block unnecessary doses and is therefore promising for clinical applications in spot-scanning proton therapy.展开更多
The purpose of this study was to grasp current potential problems of dose error in intensity-modulated proton therapy (IMPT) plans. We were interested in dose differences of the Varian Eclipse treatment planning syste...The purpose of this study was to grasp current potential problems of dose error in intensity-modulated proton therapy (IMPT) plans. We were interested in dose differences of the Varian Eclipse treatment planning system (TPS) and the fast dose calculation method (FDC) for single-field optimization (SFO) and multi-field optimization (MFO) IMPT plans. In addition, because some authors have reported dosimetric benefit of a proton arc therapy with ultimate multi-fields in recent years, we wanted to evaluate how the number of fields and beam angles affect the differences for IMPT plans. Therefore, for one brain cancer patient with a large heterogeneity, SFO and MFO IMPT plans with various multi-angle beams were planned by the TPS. Dose distributions for each IMPT plan were calculated by both the TPS’s conventional pencil beam algorithm and the FDC. The dosimetric parameters were compared between the two algorithms. The TPS overestimated 400 - 500 cGy (RBE) for minimum dose to the CTV relative to the dose calculated by the FDC. These differences indicate clinically relevant effect on clinical results. In addition, we observed that the maximum difference in dose calculated between the TPS and the FDC was about 900 cGy (RBE) for the right optic nerve, and this quantity also has a possibility to have a clinical effect. The major difference was not seen in calculations for SFO IMPT planning and those for MFO IMPT planning. Differences between the TPS and the FDC in SFO and MFO IMPT plans depend strongly on beam arrangement and the presence of a heterogeneous body. We advocate use of a Monte Carlo method in proton treatment planning to deliver the most precise proton dose in IMPT.展开更多
Background:Salvage treatment for locally recurrent nasopharyngeal carcinoma(NPC) is complicated and relatively limited.Radiotherapy,combined with effective concomitant chemotherapy,may improve clinical treatment outco...Background:Salvage treatment for locally recurrent nasopharyngeal carcinoma(NPC) is complicated and relatively limited.Radiotherapy,combined with effective concomitant chemotherapy,may improve clinical treatment outcomes.We conducted a phase Ⅱ randomized controlled trial to evaluate the efficacy of intensity-modulated radiotherapy with concomitant weekly cisplatin on locally recurrent NPC.Methods:Between April 2002 and January 2008,69 patients diagnosed with non-metastatic locally recurrent NPC were randomly assigned to either concomitant chemoradiotherapy group(n = 34) or radiotherapy alone group(n = 35).All patients received intensity-modulated radiotherapy.The radiotherapy dose for both groups was 60 Gy in 27 fractions for 37 days(range 23-53 days).The concomitant chemotherapy schedule was cisplatin 30 mg/m^2 by intravenous infusion weekly during radiotherapy.Results:The median follow-up period of all patients was 35 months(range 2-112 months).Between concomitant chemoradiotherapy and radiotherapy groups,there was only significant difference in the 3-year and 5-year overall survival(OS) rates(68.7%vs.42.2%,P = 0.016 and 41.8%vs.27.5%,P = 0.049,respectively).Subgroup analysis showed that concomitant chemoradiotherapy significantly improved the 5-year OS rate especially for patients in stage rT3-4(33.0%vs.13.2%,P = 0.009),stages Ⅲ-Ⅳ(34.3%vs.13.2%,P = 0.006),recurrence interval >30 months(49.0%vs.20.6%,P = 0.017),and tumor volume >26 cm^3(37.6%vs.0%,P = 0.006).Conclusion:Compared with radiotherapy alone,concomitant chemoradiotherapy can improve OS of the patients with locally recurrent NPC,especially those with advanced T category(rT3-4) and stage(lll-IV) diseases,recurrence intervals >30 months,and tumor volume >26 cm^3.展开更多
AIM： To evaluate the dosimetry, efficacy and toxicity of intensity-modulated radiation therapy （IMRT） and concurrent chemotherapy for patients with locally advanced cervical and upper thoracic esophageal cancer. ME...AIM： To evaluate the dosimetry, efficacy and toxicity of intensity-modulated radiation therapy （IMRT） and concurrent chemotherapy for patients with locally advanced cervical and upper thoracic esophageal cancer. METHODS： A retrospective study was performed on 7 patients who were definitively treated with IMRT and concurrent chemotherapy. Patients who did not receive IMRT radiation and concurrent chemotherapy were not included in this analysis. IMRT plans were evaluated to assess the tumor coverage and normal tissue avoidance. Treatment response was evaluated and toxicities were assessed. RESULTS： Five- to nine-beam IMRT were used to deliver a total dose of 59.4-66 Gy （median： 64.8 Gy） to the primary tumor with 6-MV photons. The minimum dose received by the planning tumor volume （PTV） of the gross tumor volume boost was 91.2%-98.2% of the prescription dose （standard deviation [SD]： 3.7%-5.7%）. The minimum dose received by the PTV Of the clinical tumor volume was 93.8%-104.8% （SD： 4.3%-11.1%） of the prescribed dose. With a median follow-up of 15 rno （range： 3-21 too）, all 6 evaluable patients achieved complete response. Of them, 2 developed local recurrences and 2 had distant metastases, 3 survived with no evidence of disease. After treatment, 2 patients developed esophageal stricture requiring frequent dilation and 1 patient developed tracheal-esophageal fistula. CONCLUSION： Concurrent IMRT and chemotherapy resulted in an excellent early response in patients with locally advanced cervical and upper thoracic esophageal cancer. However, local and distant recurrence and toxicity remain to be a problem. Innovative approaches are needed to improve the outcome.展开更多
AIM: To prospectively compare volumetric intensitymodulated arc therapy(VMAT) and conventional intensity-modulated radiation therapy(IMRT) in coverage of planning target volumes and avoidance of multiple organs at ris...AIM: To prospectively compare volumetric intensitymodulated arc therapy(VMAT) and conventional intensity-modulated radiation therapy(IMRT) in coverage of planning target volumes and avoidance of multiple organs at risk(OARs) in patients undergoing definitive chemoradiotherapy for advanced(stage Ⅲ or Ⅳ)squamous cell cancer of the head and neck. METHODS: Computed tomography scans of 20 patients with advanced tumors of the larynx, naso-, oroand hypopharynx were prospectively planned using IMRT(7 field) and VMAT using two arcs. Calculated doses to planning target volume(PTV) and OAR were compared between IMRT and VMAT plans. Dose-volume histograms(DVH) were utilized to obtain calculated doses to PTV and OAR, including parotids, cochlea,spinal cord, brainstem, anterior tongue, pituitary and brachial plexus. DVH's for all structures were compared between IMRT and VMAT plans. In addition the planswere compared for dose conformity and homogeneity. The final treatment plan was chosen by the treating radiation oncologist. RESULTS: VMAT was chosen as the ultimate plan in 18 of 20 patients(90%) because the plans were thought to be otherwise clinically equivalent. The IMRT plan was chosen in 2 of 20 patients because the VMAT plan produced concentric irradiation of the cord which was not overcome even with an avoidance structure. For all patients, VMAT plans had a lower number of average monitor units on average(MU = 542.85) than IMRT plans(MU = 1612.58)(P < 0.001). Using the conformity index(CI), defined as the 95% isodose volume divided by the PTV, the IMRT plan was more conformal with a lower conformity index(CI = 1.61) than the VMAT plan(CI = 2.00)(P = 0.003). Dose homogeneity, as measured by average standard deviation of dose distribution over the PTV, was not different with VMAT(1.45 Gy) or IMRT(1.73 Gy)(P = 0.069). There were no differences in sparing organs at risk.CONCLUSION: In this prospective study, VMAT plans were chosen over IMRT 90% of the time. Compared to IMRT, VMAT plans used only one third of the MUs, had shorter treatment times, and similar sparing of OAR. Overall, VMAT provided similar dose homogeneity but less conformity in PTV irradiation compared to IMRT. This difference in conformity was not clinically significant.展开更多
Objective This study aimed to compare and analyze the clinical efficacy and safety of late-course and simultaneous integrated dose-increasing intensity-modulated radiation therapy(IMRT) for cervical cancer complicated...Objective This study aimed to compare and analyze the clinical efficacy and safety of late-course and simultaneous integrated dose-increasing intensity-modulated radiation therapy(IMRT) for cervical cancer complicated with pelvic lymph node metastasis. Methods Sixty patients with cervical cancer complicated with pelvic lymph node metastasis who were admitted to our hospital from January 2013 to January 2015 were enrolled. The patients were randomly divided into the late-course dose-increasing IMRT group and the simultaneous integrated dose-increasing IMRT group, with 30 cases included in each group, respectively. All patients were concurrently treated with cisplatin. After treatment, the clinical outcomes of the two groups were compared. Results The remission rate of symptoms in the simultaneous integrated dose-increasing IMRT group was significantly higher than that in the late-course dose-increasing IMRT group(P < 0.05). The follow-up results showed that the overall survival time, progression-free survival time, and distant metastasis time of patients in the simultaneous integrated dose-increasing IMRT group were significantly longer than those in the late-course dose-increasing IMRT group(P < 0.05). The recurrent rate of lymph nodes in the radiation field in the simultaneous integrated dose-increasing IMRT group was significantly lower(P < 0.05) than in the late-course dose-increasing IMRT group. There was no significant difference in the incidence of cervical and vaginal recurrence and distant metastasis between the two groups(P > 0.05). The radiation doses of Dmax in the small intestine, D1 cc(the minimum dose to the 1 cc receiving the highest dose) in the bladder, and Dmax in the rectum in the simultaneous integrated dose-increasing IMRT group were significantly lower(P < 0.05) than in the late-course dose-increasing IMRT group. There was no significant difference in intestinal D2 cc(the minimum dose to the 2 cc receiving the highest dose) between the two groups(P > 0.05). The incidence of bone marrow suppression in the simultaneous integrated dose-increasing IMRT group was significantly lower(P < 0.05) than in the late-course dose-increasing IMRT group.Conclusion The application of simultaneous integrated dose-increasing IMRT in the treatment of cervical cancer patients complicated with pelvic lymph node metastasis can significantly control tumor progression, improve the long-term survival time, and postpone distant metastasis time with high safety.展开更多
Esophageal cancer is one of the most difficult cancers to treat since it is often at an advanced stage at the time of symptom presentation.For locally advanced esophageal cancer,treatment options include multidiscipli...Esophageal cancer is one of the most difficult cancers to treat since it is often at an advanced stage at the time of symptom presentation.For locally advanced esophageal cancer,treatment options include multidisciplinary treatment such as surgery or definitive chemoradiotherapy.Surgery has a high local control rate because it involves excision of the cancer along with the surrounding organs;however,it is still highly invasive,although advances in surgery have reduced the burden on patients.On the other hand,chemoradiotherapy may also be applicable in cases in which surgery is inoperable owing to complications or distant lymph node metastasis.However,chemoradiotherapy using X-ray irradiation can cause late toxicities,including those to the heart.Proton beam therapy is widely used to treat esophageal cancer because of its characteristics,and some comparisons between proton beam therapy and X-ray therapy or surgery have recently been reported.This review discusses the role of proton beam therapy in esophageal cancer in comparison to X-ray therapy and surgery.展开更多
Objective To evaluate the long-term outcome and prognostic factors of patients with nasopharyngeal carcinoma(NPC)from low-endemic regions of China who received definitive intensity-modulated radiation therapy(IMRT).Me...Objective To evaluate the long-term outcome and prognostic factors of patients with nasopharyngeal carcinoma(NPC)from low-endemic regions of China who received definitive intensity-modulated radiation therapy(IMRT).Methods The clinical data from 608 patients with newly-diagnosed non-metastatic NPC who have received initial treatment at our cancer center from January,2008 to December,2013 were retrospectively reviewed.All patients received definitive IMRT,and 87.7%received platinum-based chemotherapy.Results The median follow-up duration was 51 months(follow-up rate,98.5%;range,10–106 months)for the entire cohort.The 5-year overall survival rate was 79.7%.The 5-year local relapse-free survival rate,regional relapse-free survival rate,distant metastasis-free survival rate and progression-free survival rate were 92.4%,93.3%,79.2%and 74.3%,respectively.A total of 153 patients had experienced treatment failure,with distant metastasis as the primary cause in 77.1%(118/153).Patients with T4 or N3 diseases had a significantly poorer prognosis than other subcategories.Stage T4 and N3 were closely associated with distant metastasis,with the metastatic rate of 29.3%and 45.5%,respectively.Conclusion IMRT provides patients with non-metastatic NPC with satisfactory long-term survival.Both T stage and N stage are important prognostic factors for NPC patients.Patients with T4 or N3 diseases have significantly increased distant metastatic rates and poor survival time.展开更多
Surgical excision and postoperative radiotherapy are widely accepted therapeutic modalities for sinonasal teratocarcinosarcoma （SNTCS）. Previous studies have shown that intensity-modulated radiation therapy （IMRT）...Surgical excision and postoperative radiotherapy are widely accepted therapeutic modalities for sinonasal teratocarcinosarcoma （SNTCS）. Previous studies have shown that intensity-modulated radiation therapy （IMRT） is safe and effective for the treatment of some sinonasal malignancies. We hypothesize that use of IMRT for SNTCS may result in clinical benefits. We report here two cases of SNTCS that were treated by IMRT. One patient was given extensive IMRT involving elective neck irradiation. Follow-up examinations revealed no recurrence and metastasis 3.5 years after IMRT. Another patient simultaneously suffered from multiple systematical diseases and was administered involved-field radiotherapy. He was found to have a marginal recurrence during the follow up and eventually died 8 months after disease diagnosis. It was suggested in this study that appropriate use of IMRT for the treatment of SNTCS may achieve excellent local control.展开更多
Objective: The objective of this work was to establish adequate tolerance limits based on a certain defined institutional indices and generate published data presenting our results to the radiotherapy community. Metho...Objective: The objective of this work was to establish adequate tolerance limits based on a certain defined institutional indices and generate published data presenting our results to the radiotherapy community. Methods: One hundred paediatric patients were treated using 6-MV X-ray beams produced by Siemens ONCOR Expression linear accelerator. The clinical step-and-shoot intensity-modulated radiation therapy (IMRT) treatment plans were designed using KonRad release 2.2.23. For two treatment sites (abdomen, head and neck), the fluence maps generated by the treatment planning system were all delivered for the quality assurance (QA) which included absolute dose verification for all treatment fields, relative dose verification for each treatment field. Results: The 724 fluence maps were analyzed at three different criteria using the gamma index tool. The 3% dose difference of local prescribed dose /3 mm was considered adequate. The passing rate for all fields of all plans always exceeded 70%. The dose differences between the measured and calculated doses ranged from -2.2% to +4% [mean and standard deviation (s): 1.4 ± 1.5] for the abdominal case, and from -3.3% to +5.6% (1.3 ± 1.6) for head and neck case with total confidence limit 0.046 (4.6%). The 14/100 (14%) of the absolute point dose measurements were out of ±3% from the dose predicted by the treatment planning system. Only two cases were below -3%, while 12 cases over +3%. Conclusion: At 3% dose difference of local prescribed dose /3 mm criteria, a 75% passing a gamma criterion and 3% for absolute point dose can be achieved for abdomen and head and neck treatments site. We considered the tolerance limits based on these indices for IMRT QA adequate.展开更多
Objective The aim of the study was to propose a hypothesis that local definitive intensity-modulated radiation therapy(IMRT) should be recommended for initially diagnosed metastatic nasopharyngeal carcinoma(NPC) and d...Objective The aim of the study was to propose a hypothesis that local definitive intensity-modulated radiation therapy(IMRT) should be recommended for initially diagnosed metastatic nasopharyngeal carcinoma(NPC) and demonstrate its feasibility.Methods Recently published papers on local definitive radiotherapy for initially diagnosed metastatic NPC were reviewed to propose a hypothesis.Results Several studies revealed the survival benefits of adding local definitive radiotherapy to the systemic chemotherapy in patients initially diagnosed with metastatic NPC.Conclusion We suggested that local definitive IMRT should be recommended in patients initially diagnosed with NPC with distant metastasis after an effective systemic chemotherapy, which may possibly prolong their survival time and potentially treat the disease.展开更多
BACKGROUND Liver cancer treatment is characterized by multidisciplinary participation and coexistence of multiple treatment methods.Hypofractionated and intensity-modulated radiotherapy is a new precise radiotherapy t...BACKGROUND Liver cancer treatment is characterized by multidisciplinary participation and coexistence of multiple treatment methods.Hypofractionated and intensity-modulated radiotherapy is a new precise radiotherapy technique applied to the treatment of systemic malignant tumors.There is a lack of understanding of hypofractionated and intensity-modulated radiotherapy combined with systemic therapy in metastatic hepatocellular carcinoma(HCC).CASE SUMMARY We report a case of metastatic HCC treated with hypofractionated and intensity-modulated radiotherapy combined with systemic therapy.A 41-year-old man was diagnosed with metastatic HCC(T3N1M1 stage IVB).Because it was found to be in the late stage of cancer and had already metastasized,it was impossible to undergo surgical treatment.In addition to aggressive comprehensive treatment for the primary lesion,local treatment for metastatic cancer can improve the patient's survival potential.Hypofractionated and intensity-modulated radiotherapy can provide a larger single treatment dose within a shorter overall treatment time,and improve the local control rate of the tumor.Follow-up examination demonstrated that the tumor and metastatic lesions had shrunk after therapy.The treatment has showed good efficacy.The patient survived for 18 months without disease progression and stable disease persisted for>38 months.CONCLUSION Targeted therapy and immunotherapy followed by hypofractionated and intensity-modulated radiotherapy are also effective for advanced metastatic HCC.展开更多
Objective We aimed to determine the ef ects of low- and high-energy intensity-modulated radiation therapy （IMRT） photon beams on the target volume planning and on the critical organs in the case of prostate can-cer....Objective We aimed to determine the ef ects of low- and high-energy intensity-modulated radiation therapy （IMRT） photon beams on the target volume planning and on the critical organs in the case of prostate can-cer. Methods Thirty plans were generated by using either 6 MV or 15 MV beams separately, and a combination of both 6 and 15 MV beams. Al plans were generated by using suitable planning objectives and dose con-straints, which were identical across the plans, except the beam energy. The plans were analyzed in terms of their target coverage, conformity, and homogeneity, regardless of the beam energy. Results The mean percentage values of V70 Gy for the rectal wal for the plans with 6 MV, 15 MV, and mixed-energy beams were 16.9%, 17.8%, and 16.4%, respectively, while the mean percentage values of V40 Gy were 53.6%, 52.3%, and 50.4%. The mean dose values to the femoral heads for the 6 MV, 15 MV, and mixed-en-ergy plans were 30.1 Gy, 25.5 Gy, and 25.4 Gy, respectively. The mean integral dose for the 6 MV plans was 10% larger than those for the 15 MV and mixed-energy plans.Conclusion These preliminary results suggest that mixed-energy IMRT plans may be advantageous with respect to the dosimetric characteristics of low- and high-energy beams. Although the reduction of dose to the organs at risk may not be clinical y relevant, in this study, IMRT plans using mixed-energy beams exhibited better OAR sparing and overal higher plan quality for deep-seated tumors.展开更多
Intensity-modulated radiation therapy (IMRT) has become the mainstay of treatment for localized prostate cancer. In IMRT, minimizing differences between the conditions used during planning CT and daily treatment is im...Intensity-modulated radiation therapy (IMRT) has become the mainstay of treatment for localized prostate cancer. In IMRT, minimizing differences between the conditions used during planning CT and daily treatment is important to prevent adverse events in normal tissues. In the present study, we evaluated the impact of variation in bladder volume on the doses to various organs. A total of 35 patients underwent definitive radiotherapy at Saitama Medical Center. A Light Speed RT16 (GE Healthcare) was used for planning and to obtain examination CT images. Such images were acquired after 4 - 6 days of planning CT image acquisition. The IMRT plans were optimized using the planning CT data to satisfy the dose constraints set by our in-house protocols for the PTV and the OARs. The dose distributions were then re-calculated using the same IMRT beams, and checked on examination CT images. It was clear that bladder volume affected the doses to certain organs. We focused on the prostate, bladder, rectum, small bowel, and large bowel. Regression coefficients were calculated for variables that correlated strongly with bladder volume (p < 0.05). We found that variation in bladder volume [cm<sup>3</sup>] predicted deviations in the bladder V<sub>70Gy</sub>, V<sub>50Gy</sub>, and V<sub>30Gy</sub> [%];the maximum dose to the small bowel [cGy];and the maximum dose to the large bowel [cGy]. The regression coefficients were -0.065, -0.125, -0.180, -10.22, and -9.831, respectively. We evaluated the impacts of such variation on organ doses. These may be helpful when checking a patient’s bladder volume before daily IMRT for localized prostate cancer.展开更多
Objective:To study the effect of Tegafur Gimeracil Oteracil Potassium Capsule + Kangai injection + intensity-modulated radiation therapy on the cellular malignant biological processes in advanced cervical cancer lesio...Objective:To study the effect of Tegafur Gimeracil Oteracil Potassium Capsule + Kangai injection + intensity-modulated radiation therapy on the cellular malignant biological processes in advanced cervical cancer lesion.Methods: Patients who were diagnosed with advanced cervical cancer in the Second People Hospital of Banan District Chongqing between April 2015 and March 2017 were selected and divided into two groups, group A received Tegafur Gimeracil Oteracil Potassium Capsule + Kangai injection + intensity-modulated radiation therapy, and group B received cisplatin + intensity-modulated radiation therapy. Serum contents of tumor markers, tumor invasion molecules and tumor proliferation molecules of two groups of patients were detected before treatment as well as 2 weeks and 4 weeks after treatment.Results: Serum E-cad, STMN1, Fas and p53 levels of both groups of patients 2 weeks and 4 weeks after treatment were significantly higher than those before treatment while TSGF, TK1, SCC-Ag, CA125, OPN, MMP9, NGAL, CyclinE, CyclinD1 and PCNA levels were significantly lower than those before treatment, and serum E-cad, STMN1, Fas and p53 levels of group A 2 weeks and 4 weeks after treatment were significantly higher than those of group B while TSGF, TK1, SCC-Ag, CA125, OPN, MMP9, NGAL, CyclinE, CyclinD1 and PCNA levels were significantly lower than those of group B.Conclusion: Tegafur Gimeracil Oteracil Potassium Capsule + Kangai injection + intensity-modulated radiation therapy for advanced cervical cancer can induce cancer cell apoptosis and inhibit cancer cell proliferation and invasion.展开更多
Objective:To carry out dosimetric comparison between volumetric modulated arc therapy(VMAT)and intensity-modulated radiation therapy(IMRT)in cervical cancer.Methods:50 postoperative cervical cancer patients were inclu...Objective:To carry out dosimetric comparison between volumetric modulated arc therapy(VMAT)and intensity-modulated radiation therapy(IMRT)in cervical cancer.Methods:50 postoperative cervical cancer patients were included in this study.The patients were admitted for treatment from January 2021 to January 2022.VMAT and IMRT plans were designed for each patient to analyze the dose distribution in the target area of the two treatment techniques.Results:Comparing the monitor unit for single treatment(638.21±116.21 MU)and time of single treatment(143.21±23.14 s)in the observation group and the monitor unit for single treatment(932.14±74.11 MU)and time of single treatment(223.14±17.26 s)in the control group,there was significant difference(P<0.05);there was also significant difference(P<0.05)between the normal tissue(bladder and rectum)of the observation group and that(bladder and rectum)of the control group.Conclusion:VMAT is more effective in cervical cancer,and it has a certain protective effect on normal tissues in patients and can reduce the radiation dose.展开更多
Hepatocellular carcinoma(HCC) is the second leading cause of cancer-related death, as few patients can be treated with currently available curative local modalities. In patients with HCC where curative modalities are ...Hepatocellular carcinoma(HCC) is the second leading cause of cancer-related death, as few patients can be treated with currently available curative local modalities. In patients with HCC where curative modalities are not feasible, radiation therapy(RT) has emerged as an alternative or combination therapy. With the development of various technologies, RT has been increasingly used for the management of HCC. Among these advances, proton beam therapy(PBT) has several unique physical properties that give it a finite range in a distal direction, and thus no exit dose along the beam path. Therefore, PBT has dosimetric advantages compared with X-ray therapy for the treatment of HCC. Indeed, various reports in the literature have described the favorable clinical outcomes and improved safety of PBT for HCC patients compared with X-ray therapy. However, there are some technical issues regarding the use of PBT in HCC, including uncertainty of organ motion and inaccuracy during calculation of tissue density and beam range, all of which may reduce the robustness of a PBT treatment plan. In this review, we discuss the physical properties, current clinical data, technical issues, and future perspectives on PBT for the treatment of HCC.展开更多
The collection efficiency of monitor parallel plate ionization chambers is the main uncertainty in the beam control of pencil beam scanning systems.Existing calculation methods for collection efficiency in photon or p...The collection efficiency of monitor parallel plate ionization chambers is the main uncertainty in the beam control of pencil beam scanning systems.Existing calculation methods for collection efficiency in photon or passive scattering proton systems have not considered the characteristics of non-uniform charge density in pencil beam scanning systems.In this study,Boag’s theory was applied to a proton pencil beam scanning system.The transverse distribution of charge density in the ionization chamber was considered to be a Gaussian function and an analytical solution was derived to calculate collection efficiency in the beam spot area.This calculation method is called the integral method and it was used to investigate the effects of beam parameters on collection efficiency.It was determined that collection efficiency is positively correlated with applied voltage,beam size,and beam energy,but negatively correlated with beam current intensity.Additionally,it was confirmed that collection efficiency is improved when the air filling the monitor parallel plate ionization chamber is replaced with nitrogen.展开更多
A synchrotron-based proton therapy(PT)facility that conforms with the requirement of future development trend in compact PT can be operated without an energy selection system.This article demonstrates a novel radiatio...A synchrotron-based proton therapy(PT)facility that conforms with the requirement of future development trend in compact PT can be operated without an energy selection system.This article demonstrates a novel radiation shielding design for this purpose.Various FLUKAbased Monte Carlo simulations have been performed to validate its feasibility.In this design,two different shielding scenarios(3-m-thick concrete and 2-m-thick iron–concrete)are proved able to reduce the public annual dose to the limit of 0.1 mSv/year.The calculation result shows that the non-primary radiation from a PT system without an inner shielding wall complies with the IEC 60601-2-64 international standard,making a single room a reality.Moreover,the H/D value of this design decreases from 2.14 to 0.32 mSv/Gy when the distance ranges from 50 to 150 cm from the isocenter,which is consistent with the previous result from another study.By establishing a typical time schedule and procedures in a treatment day for a single room in the simulation,a non-urgent machine maintenance time of 10 min after treatment is recommended,and the residual radiation level in most areas can be reduced to 2.5 lSv/h.The annual dose for radiation therapists coming from the residual radiation is 1 mSv,which is 20%of the target design.In general,this shielding design ensures a low cost and compact facility compared with the cyclotron-based PT system.展开更多
Radiation for targeting liver tumors can be challenging because of the damage that it can cause to sensitive organs such as heart and kidney.To calculate the dose received by noninvolved organs,a modeling of the pati...Radiation for targeting liver tumors can be challenging because of the damage that it can cause to sensitive organs such as heart and kidney.To calculate the dose received by noninvolved organs,a modeling of the patient’s entire body is necessary.Therefore,in this study,a human Oak Ridge National Laboratory-Medical Internal Radiation Dose phantom was used for liver proton therapy simulation.The results show that the optimum proton energy interval covering the whole tumor was in the range of 90-120 MeV.A spread-out Bragg peak was built by adding Bragg peaks to cover the liver tumor volume,and beam parameters recommended by the International Commission on Radiation Units and Measurements(ICRU) were evaluated.The flux of secondary particles was calculated on the surface of the tumor,and two-dimensional dose distributions for protons,neutrons and photons were shown.Finally,the total doses of protons,photons and neutrons in tumor and 14 noninvolved organs were calculated.The results indicated that the ratio of received dose to the normal tissue of the liver concerning the spherical tumor of 2 cm in radius was approximately0.01.This ratio for organs such as gall bladder,heart and kidney was approximately 8.4×10-5,5.1×10-5 and2.34×10-5.Secondary particles such as neutrons andphotons deposit their energies to organs located far from the treatment volume,thus increasing the risk of secondary cancers.The research results indicated that the secondary particles dose was quite small in liver proton therapy.All the calculations were performed using Monte Carlo N-Particle Transport Code (MCNP).展开更多
基金supported by the Key Program of the 13th Five-Year Plan,the Hefei Institutes of Physical Science of the Chinese Academy of Sciences(No.KP-2017-24)
文摘Intensity-modulated proton therapy(IMPT)is becoming essential for proton therapy and is under rapid development.However,for IMPT,the lateral penumbra of the spot-scanning proton beam is still an urgent issue to be solved.Patient-specific block collimators(PSBCs),which can block unnecessary doses,play a crucial role in passive scattering delivery technology but are rarely used in spot scanning.One objective of this study is to investigate the lateral penumbra variations of intensity-modulated spot scanning with and without a PSBC.For fields with varying degrees of sharpness and at varying depths in a water phantom,the lateral penumbral widths were calculated using a Monte Carlo-based dose engine from RayStation 6.The results suggest that the lateral penumbral widths can be reduced by more than 30%for uniform target volumes,regardless of whether a range-shifter is used,and that the maximum dose beyond the field edges can be reduced significantly.The results of patient cases show that the doses in organs-at-risk near the edge of the target volume decrease if a PSBC is implemented.This study demonstrates that intensity-modulated spot scanning with a PSBC can effectively reduce the lateral penumbra and block unnecessary doses and is therefore promising for clinical applications in spot-scanning proton therapy.
文摘The purpose of this study was to grasp current potential problems of dose error in intensity-modulated proton therapy (IMPT) plans. We were interested in dose differences of the Varian Eclipse treatment planning system (TPS) and the fast dose calculation method (FDC) for single-field optimization (SFO) and multi-field optimization (MFO) IMPT plans. In addition, because some authors have reported dosimetric benefit of a proton arc therapy with ultimate multi-fields in recent years, we wanted to evaluate how the number of fields and beam angles affect the differences for IMPT plans. Therefore, for one brain cancer patient with a large heterogeneity, SFO and MFO IMPT plans with various multi-angle beams were planned by the TPS. Dose distributions for each IMPT plan were calculated by both the TPS’s conventional pencil beam algorithm and the FDC. The dosimetric parameters were compared between the two algorithms. The TPS overestimated 400 - 500 cGy (RBE) for minimum dose to the CTV relative to the dose calculated by the FDC. These differences indicate clinically relevant effect on clinical results. In addition, we observed that the maximum difference in dose calculated between the TPS and the FDC was about 900 cGy (RBE) for the right optic nerve, and this quantity also has a possibility to have a clinical effect. The major difference was not seen in calculations for SFO IMPT planning and those for MFO IMPT planning. Differences between the TPS and the FDC in SFO and MFO IMPT plans depend strongly on beam arrangement and the presence of a heterogeneous body. We advocate use of a Monte Carlo method in proton treatment planning to deliver the most precise proton dose in IMPT.
文摘Background:Salvage treatment for locally recurrent nasopharyngeal carcinoma(NPC) is complicated and relatively limited.Radiotherapy,combined with effective concomitant chemotherapy,may improve clinical treatment outcomes.We conducted a phase Ⅱ randomized controlled trial to evaluate the efficacy of intensity-modulated radiotherapy with concomitant weekly cisplatin on locally recurrent NPC.Methods:Between April 2002 and January 2008,69 patients diagnosed with non-metastatic locally recurrent NPC were randomly assigned to either concomitant chemoradiotherapy group(n = 34) or radiotherapy alone group(n = 35).All patients received intensity-modulated radiotherapy.The radiotherapy dose for both groups was 60 Gy in 27 fractions for 37 days(range 23-53 days).The concomitant chemotherapy schedule was cisplatin 30 mg/m^2 by intravenous infusion weekly during radiotherapy.Results:The median follow-up period of all patients was 35 months(range 2-112 months).Between concomitant chemoradiotherapy and radiotherapy groups,there was only significant difference in the 3-year and 5-year overall survival(OS) rates(68.7%vs.42.2%,P = 0.016 and 41.8%vs.27.5%,P = 0.049,respectively).Subgroup analysis showed that concomitant chemoradiotherapy significantly improved the 5-year OS rate especially for patients in stage rT3-4(33.0%vs.13.2%,P = 0.009),stages Ⅲ-Ⅳ(34.3%vs.13.2%,P = 0.006),recurrence interval >30 months(49.0%vs.20.6%,P = 0.017),and tumor volume >26 cm^3(37.6%vs.0%,P = 0.006).Conclusion:Compared with radiotherapy alone,concomitant chemoradiotherapy can improve OS of the patients with locally recurrent NPC,especially those with advanced T category(rT3-4) and stage(lll-IV) diseases,recurrence intervals >30 months,and tumor volume >26 cm^3.
基金Supported by Radiology Society of Northern America Researh and Education Program, Grant to "Teach the Teachers" from Emerging Nations
文摘AIM： To evaluate the dosimetry, efficacy and toxicity of intensity-modulated radiation therapy （IMRT） and concurrent chemotherapy for patients with locally advanced cervical and upper thoracic esophageal cancer. METHODS： A retrospective study was performed on 7 patients who were definitively treated with IMRT and concurrent chemotherapy. Patients who did not receive IMRT radiation and concurrent chemotherapy were not included in this analysis. IMRT plans were evaluated to assess the tumor coverage and normal tissue avoidance. Treatment response was evaluated and toxicities were assessed. RESULTS： Five- to nine-beam IMRT were used to deliver a total dose of 59.4-66 Gy （median： 64.8 Gy） to the primary tumor with 6-MV photons. The minimum dose received by the planning tumor volume （PTV） of the gross tumor volume boost was 91.2%-98.2% of the prescription dose （standard deviation [SD]： 3.7%-5.7%）. The minimum dose received by the PTV Of the clinical tumor volume was 93.8%-104.8% （SD： 4.3%-11.1%） of the prescribed dose. With a median follow-up of 15 rno （range： 3-21 too）, all 6 evaluable patients achieved complete response. Of them, 2 developed local recurrences and 2 had distant metastases, 3 survived with no evidence of disease. After treatment, 2 patients developed esophageal stricture requiring frequent dilation and 1 patient developed tracheal-esophageal fistula. CONCLUSION： Concurrent IMRT and chemotherapy resulted in an excellent early response in patients with locally advanced cervical and upper thoracic esophageal cancer. However, local and distant recurrence and toxicity remain to be a problem. Innovative approaches are needed to improve the outcome.
文摘AIM: To prospectively compare volumetric intensitymodulated arc therapy(VMAT) and conventional intensity-modulated radiation therapy(IMRT) in coverage of planning target volumes and avoidance of multiple organs at risk(OARs) in patients undergoing definitive chemoradiotherapy for advanced(stage Ⅲ or Ⅳ)squamous cell cancer of the head and neck. METHODS: Computed tomography scans of 20 patients with advanced tumors of the larynx, naso-, oroand hypopharynx were prospectively planned using IMRT(7 field) and VMAT using two arcs. Calculated doses to planning target volume(PTV) and OAR were compared between IMRT and VMAT plans. Dose-volume histograms(DVH) were utilized to obtain calculated doses to PTV and OAR, including parotids, cochlea,spinal cord, brainstem, anterior tongue, pituitary and brachial plexus. DVH's for all structures were compared between IMRT and VMAT plans. In addition the planswere compared for dose conformity and homogeneity. The final treatment plan was chosen by the treating radiation oncologist. RESULTS: VMAT was chosen as the ultimate plan in 18 of 20 patients(90%) because the plans were thought to be otherwise clinically equivalent. The IMRT plan was chosen in 2 of 20 patients because the VMAT plan produced concentric irradiation of the cord which was not overcome even with an avoidance structure. For all patients, VMAT plans had a lower number of average monitor units on average(MU = 542.85) than IMRT plans(MU = 1612.58)(P < 0.001). Using the conformity index(CI), defined as the 95% isodose volume divided by the PTV, the IMRT plan was more conformal with a lower conformity index(CI = 1.61) than the VMAT plan(CI = 2.00)(P = 0.003). Dose homogeneity, as measured by average standard deviation of dose distribution over the PTV, was not different with VMAT(1.45 Gy) or IMRT(1.73 Gy)(P = 0.069). There were no differences in sparing organs at risk.CONCLUSION: In this prospective study, VMAT plans were chosen over IMRT 90% of the time. Compared to IMRT, VMAT plans used only one third of the MUs, had shorter treatment times, and similar sparing of OAR. Overall, VMAT provided similar dose homogeneity but less conformity in PTV irradiation compared to IMRT. This difference in conformity was not clinically significant.
文摘Objective This study aimed to compare and analyze the clinical efficacy and safety of late-course and simultaneous integrated dose-increasing intensity-modulated radiation therapy(IMRT) for cervical cancer complicated with pelvic lymph node metastasis. Methods Sixty patients with cervical cancer complicated with pelvic lymph node metastasis who were admitted to our hospital from January 2013 to January 2015 were enrolled. The patients were randomly divided into the late-course dose-increasing IMRT group and the simultaneous integrated dose-increasing IMRT group, with 30 cases included in each group, respectively. All patients were concurrently treated with cisplatin. After treatment, the clinical outcomes of the two groups were compared. Results The remission rate of symptoms in the simultaneous integrated dose-increasing IMRT group was significantly higher than that in the late-course dose-increasing IMRT group(P < 0.05). The follow-up results showed that the overall survival time, progression-free survival time, and distant metastasis time of patients in the simultaneous integrated dose-increasing IMRT group were significantly longer than those in the late-course dose-increasing IMRT group(P < 0.05). The recurrent rate of lymph nodes in the radiation field in the simultaneous integrated dose-increasing IMRT group was significantly lower(P < 0.05) than in the late-course dose-increasing IMRT group. There was no significant difference in the incidence of cervical and vaginal recurrence and distant metastasis between the two groups(P > 0.05). The radiation doses of Dmax in the small intestine, D1 cc(the minimum dose to the 1 cc receiving the highest dose) in the bladder, and Dmax in the rectum in the simultaneous integrated dose-increasing IMRT group were significantly lower(P < 0.05) than in the late-course dose-increasing IMRT group. There was no significant difference in intestinal D2 cc(the minimum dose to the 2 cc receiving the highest dose) between the two groups(P > 0.05). The incidence of bone marrow suppression in the simultaneous integrated dose-increasing IMRT group was significantly lower(P < 0.05) than in the late-course dose-increasing IMRT group.Conclusion The application of simultaneous integrated dose-increasing IMRT in the treatment of cervical cancer patients complicated with pelvic lymph node metastasis can significantly control tumor progression, improve the long-term survival time, and postpone distant metastasis time with high safety.
文摘Esophageal cancer is one of the most difficult cancers to treat since it is often at an advanced stage at the time of symptom presentation.For locally advanced esophageal cancer,treatment options include multidisciplinary treatment such as surgery or definitive chemoradiotherapy.Surgery has a high local control rate because it involves excision of the cancer along with the surrounding organs;however,it is still highly invasive,although advances in surgery have reduced the burden on patients.On the other hand,chemoradiotherapy may also be applicable in cases in which surgery is inoperable owing to complications or distant lymph node metastasis.However,chemoradiotherapy using X-ray irradiation can cause late toxicities,including those to the heart.Proton beam therapy is widely used to treat esophageal cancer because of its characteristics,and some comparisons between proton beam therapy and X-ray therapy or surgery have recently been reported.This review discusses the role of proton beam therapy in esophageal cancer in comparison to X-ray therapy and surgery.
文摘Objective To evaluate the long-term outcome and prognostic factors of patients with nasopharyngeal carcinoma(NPC)from low-endemic regions of China who received definitive intensity-modulated radiation therapy(IMRT).Methods The clinical data from 608 patients with newly-diagnosed non-metastatic NPC who have received initial treatment at our cancer center from January,2008 to December,2013 were retrospectively reviewed.All patients received definitive IMRT,and 87.7%received platinum-based chemotherapy.Results The median follow-up duration was 51 months(follow-up rate,98.5%;range,10–106 months)for the entire cohort.The 5-year overall survival rate was 79.7%.The 5-year local relapse-free survival rate,regional relapse-free survival rate,distant metastasis-free survival rate and progression-free survival rate were 92.4%,93.3%,79.2%and 74.3%,respectively.A total of 153 patients had experienced treatment failure,with distant metastasis as the primary cause in 77.1%(118/153).Patients with T4 or N3 diseases had a significantly poorer prognosis than other subcategories.Stage T4 and N3 were closely associated with distant metastasis,with the metastatic rate of 29.3%and 45.5%,respectively.Conclusion IMRT provides patients with non-metastatic NPC with satisfactory long-term survival.Both T stage and N stage are important prognostic factors for NPC patients.Patients with T4 or N3 diseases have significantly increased distant metastatic rates and poor survival time.
文摘Surgical excision and postoperative radiotherapy are widely accepted therapeutic modalities for sinonasal teratocarcinosarcoma （SNTCS）. Previous studies have shown that intensity-modulated radiation therapy （IMRT） is safe and effective for the treatment of some sinonasal malignancies. We hypothesize that use of IMRT for SNTCS may result in clinical benefits. We report here two cases of SNTCS that were treated by IMRT. One patient was given extensive IMRT involving elective neck irradiation. Follow-up examinations revealed no recurrence and metastasis 3.5 years after IMRT. Another patient simultaneously suffered from multiple systematical diseases and was administered involved-field radiotherapy. He was found to have a marginal recurrence during the follow up and eventually died 8 months after disease diagnosis. It was suggested in this study that appropriate use of IMRT for the treatment of SNTCS may achieve excellent local control.
文摘Objective: The objective of this work was to establish adequate tolerance limits based on a certain defined institutional indices and generate published data presenting our results to the radiotherapy community. Methods: One hundred paediatric patients were treated using 6-MV X-ray beams produced by Siemens ONCOR Expression linear accelerator. The clinical step-and-shoot intensity-modulated radiation therapy (IMRT) treatment plans were designed using KonRad release 2.2.23. For two treatment sites (abdomen, head and neck), the fluence maps generated by the treatment planning system were all delivered for the quality assurance (QA) which included absolute dose verification for all treatment fields, relative dose verification for each treatment field. Results: The 724 fluence maps were analyzed at three different criteria using the gamma index tool. The 3% dose difference of local prescribed dose /3 mm was considered adequate. The passing rate for all fields of all plans always exceeded 70%. The dose differences between the measured and calculated doses ranged from -2.2% to +4% [mean and standard deviation (s): 1.4 ± 1.5] for the abdominal case, and from -3.3% to +5.6% (1.3 ± 1.6) for head and neck case with total confidence limit 0.046 (4.6%). The 14/100 (14%) of the absolute point dose measurements were out of ±3% from the dose predicted by the treatment planning system. Only two cases were below -3%, while 12 cases over +3%. Conclusion: At 3% dose difference of local prescribed dose /3 mm criteria, a 75% passing a gamma criterion and 3% for absolute point dose can be achieved for abdomen and head and neck treatments site. We considered the tolerance limits based on these indices for IMRT QA adequate.
基金Supported by grants from Beijing Xisike Clinical Oncology Research Foundation(No.Y-Q201801-059)CSCO-Merck Serono Oncology Research Fund(No.Y-MT2015-007)
文摘Objective The aim of the study was to propose a hypothesis that local definitive intensity-modulated radiation therapy(IMRT) should be recommended for initially diagnosed metastatic nasopharyngeal carcinoma(NPC) and demonstrate its feasibility.Methods Recently published papers on local definitive radiotherapy for initially diagnosed metastatic NPC were reviewed to propose a hypothesis.Results Several studies revealed the survival benefits of adding local definitive radiotherapy to the systemic chemotherapy in patients initially diagnosed with metastatic NPC.Conclusion We suggested that local definitive IMRT should be recommended in patients initially diagnosed with NPC with distant metastasis after an effective systemic chemotherapy, which may possibly prolong their survival time and potentially treat the disease.
基金Supported by Guangxi Guilin Science and Technology Fund,No.20220139-9-8.
文摘BACKGROUND Liver cancer treatment is characterized by multidisciplinary participation and coexistence of multiple treatment methods.Hypofractionated and intensity-modulated radiotherapy is a new precise radiotherapy technique applied to the treatment of systemic malignant tumors.There is a lack of understanding of hypofractionated and intensity-modulated radiotherapy combined with systemic therapy in metastatic hepatocellular carcinoma(HCC).CASE SUMMARY We report a case of metastatic HCC treated with hypofractionated and intensity-modulated radiotherapy combined with systemic therapy.A 41-year-old man was diagnosed with metastatic HCC(T3N1M1 stage IVB).Because it was found to be in the late stage of cancer and had already metastasized,it was impossible to undergo surgical treatment.In addition to aggressive comprehensive treatment for the primary lesion,local treatment for metastatic cancer can improve the patient's survival potential.Hypofractionated and intensity-modulated radiotherapy can provide a larger single treatment dose within a shorter overall treatment time,and improve the local control rate of the tumor.Follow-up examination demonstrated that the tumor and metastatic lesions had shrunk after therapy.The treatment has showed good efficacy.The patient survived for 18 months without disease progression and stable disease persisted for>38 months.CONCLUSION Targeted therapy and immunotherapy followed by hypofractionated and intensity-modulated radiotherapy are also effective for advanced metastatic HCC.
文摘Objective We aimed to determine the ef ects of low- and high-energy intensity-modulated radiation therapy （IMRT） photon beams on the target volume planning and on the critical organs in the case of prostate can-cer. Methods Thirty plans were generated by using either 6 MV or 15 MV beams separately, and a combination of both 6 and 15 MV beams. Al plans were generated by using suitable planning objectives and dose con-straints, which were identical across the plans, except the beam energy. The plans were analyzed in terms of their target coverage, conformity, and homogeneity, regardless of the beam energy. Results The mean percentage values of V70 Gy for the rectal wal for the plans with 6 MV, 15 MV, and mixed-energy beams were 16.9%, 17.8%, and 16.4%, respectively, while the mean percentage values of V40 Gy were 53.6%, 52.3%, and 50.4%. The mean dose values to the femoral heads for the 6 MV, 15 MV, and mixed-en-ergy plans were 30.1 Gy, 25.5 Gy, and 25.4 Gy, respectively. The mean integral dose for the 6 MV plans was 10% larger than those for the 15 MV and mixed-energy plans.Conclusion These preliminary results suggest that mixed-energy IMRT plans may be advantageous with respect to the dosimetric characteristics of low- and high-energy beams. Although the reduction of dose to the organs at risk may not be clinical y relevant, in this study, IMRT plans using mixed-energy beams exhibited better OAR sparing and overal higher plan quality for deep-seated tumors.
文摘Intensity-modulated radiation therapy (IMRT) has become the mainstay of treatment for localized prostate cancer. In IMRT, minimizing differences between the conditions used during planning CT and daily treatment is important to prevent adverse events in normal tissues. In the present study, we evaluated the impact of variation in bladder volume on the doses to various organs. A total of 35 patients underwent definitive radiotherapy at Saitama Medical Center. A Light Speed RT16 (GE Healthcare) was used for planning and to obtain examination CT images. Such images were acquired after 4 - 6 days of planning CT image acquisition. The IMRT plans were optimized using the planning CT data to satisfy the dose constraints set by our in-house protocols for the PTV and the OARs. The dose distributions were then re-calculated using the same IMRT beams, and checked on examination CT images. It was clear that bladder volume affected the doses to certain organs. We focused on the prostate, bladder, rectum, small bowel, and large bowel. Regression coefficients were calculated for variables that correlated strongly with bladder volume (p < 0.05). We found that variation in bladder volume [cm<sup>3</sup>] predicted deviations in the bladder V<sub>70Gy</sub>, V<sub>50Gy</sub>, and V<sub>30Gy</sub> [%];the maximum dose to the small bowel [cGy];and the maximum dose to the large bowel [cGy]. The regression coefficients were -0.065, -0.125, -0.180, -10.22, and -9.831, respectively. We evaluated the impacts of such variation on organ doses. These may be helpful when checking a patient’s bladder volume before daily IMRT for localized prostate cancer.
文摘Objective:To study the effect of Tegafur Gimeracil Oteracil Potassium Capsule + Kangai injection + intensity-modulated radiation therapy on the cellular malignant biological processes in advanced cervical cancer lesion.Methods: Patients who were diagnosed with advanced cervical cancer in the Second People Hospital of Banan District Chongqing between April 2015 and March 2017 were selected and divided into two groups, group A received Tegafur Gimeracil Oteracil Potassium Capsule + Kangai injection + intensity-modulated radiation therapy, and group B received cisplatin + intensity-modulated radiation therapy. Serum contents of tumor markers, tumor invasion molecules and tumor proliferation molecules of two groups of patients were detected before treatment as well as 2 weeks and 4 weeks after treatment.Results: Serum E-cad, STMN1, Fas and p53 levels of both groups of patients 2 weeks and 4 weeks after treatment were significantly higher than those before treatment while TSGF, TK1, SCC-Ag, CA125, OPN, MMP9, NGAL, CyclinE, CyclinD1 and PCNA levels were significantly lower than those before treatment, and serum E-cad, STMN1, Fas and p53 levels of group A 2 weeks and 4 weeks after treatment were significantly higher than those of group B while TSGF, TK1, SCC-Ag, CA125, OPN, MMP9, NGAL, CyclinE, CyclinD1 and PCNA levels were significantly lower than those of group B.Conclusion: Tegafur Gimeracil Oteracil Potassium Capsule + Kangai injection + intensity-modulated radiation therapy for advanced cervical cancer can induce cancer cell apoptosis and inhibit cancer cell proliferation and invasion.
文摘Objective:To carry out dosimetric comparison between volumetric modulated arc therapy(VMAT)and intensity-modulated radiation therapy(IMRT)in cervical cancer.Methods:50 postoperative cervical cancer patients were included in this study.The patients were admitted for treatment from January 2021 to January 2022.VMAT and IMRT plans were designed for each patient to analyze the dose distribution in the target area of the two treatment techniques.Results:Comparing the monitor unit for single treatment(638.21±116.21 MU)and time of single treatment(143.21±23.14 s)in the observation group and the monitor unit for single treatment(932.14±74.11 MU)and time of single treatment(223.14±17.26 s)in the control group,there was significant difference(P<0.05);there was also significant difference(P<0.05)between the normal tissue(bladder and rectum)of the observation group and that(bladder and rectum)of the control group.Conclusion:VMAT is more effective in cervical cancer,and it has a certain protective effect on normal tissues in patients and can reduce the radiation dose.
基金Supported by a Grant from the Marine Biotechnology Program funded by the Ministry of Oceans and Fisheries,South Korea,No.20150220
文摘Hepatocellular carcinoma(HCC) is the second leading cause of cancer-related death, as few patients can be treated with currently available curative local modalities. In patients with HCC where curative modalities are not feasible, radiation therapy(RT) has emerged as an alternative or combination therapy. With the development of various technologies, RT has been increasingly used for the management of HCC. Among these advances, proton beam therapy(PBT) has several unique physical properties that give it a finite range in a distal direction, and thus no exit dose along the beam path. Therefore, PBT has dosimetric advantages compared with X-ray therapy for the treatment of HCC. Indeed, various reports in the literature have described the favorable clinical outcomes and improved safety of PBT for HCC patients compared with X-ray therapy. However, there are some technical issues regarding the use of PBT in HCC, including uncertainty of organ motion and inaccuracy during calculation of tissue density and beam range, all of which may reduce the robustness of a PBT treatment plan. In this review, we discuss the physical properties, current clinical data, technical issues, and future perspectives on PBT for the treatment of HCC.
文摘The collection efficiency of monitor parallel plate ionization chambers is the main uncertainty in the beam control of pencil beam scanning systems.Existing calculation methods for collection efficiency in photon or passive scattering proton systems have not considered the characteristics of non-uniform charge density in pencil beam scanning systems.In this study,Boag’s theory was applied to a proton pencil beam scanning system.The transverse distribution of charge density in the ionization chamber was considered to be a Gaussian function and an analytical solution was derived to calculate collection efficiency in the beam spot area.This calculation method is called the integral method and it was used to investigate the effects of beam parameters on collection efficiency.It was determined that collection efficiency is positively correlated with applied voltage,beam size,and beam energy,but negatively correlated with beam current intensity.Additionally,it was confirmed that collection efficiency is improved when the air filling the monitor parallel plate ionization chamber is replaced with nitrogen.
基金partially supported by the China Postdoctoral Science Foundation(No.2019M650611)
文摘A synchrotron-based proton therapy(PT)facility that conforms with the requirement of future development trend in compact PT can be operated without an energy selection system.This article demonstrates a novel radiation shielding design for this purpose.Various FLUKAbased Monte Carlo simulations have been performed to validate its feasibility.In this design,two different shielding scenarios(3-m-thick concrete and 2-m-thick iron–concrete)are proved able to reduce the public annual dose to the limit of 0.1 mSv/year.The calculation result shows that the non-primary radiation from a PT system without an inner shielding wall complies with the IEC 60601-2-64 international standard,making a single room a reality.Moreover,the H/D value of this design decreases from 2.14 to 0.32 mSv/Gy when the distance ranges from 50 to 150 cm from the isocenter,which is consistent with the previous result from another study.By establishing a typical time schedule and procedures in a treatment day for a single room in the simulation,a non-urgent machine maintenance time of 10 min after treatment is recommended,and the residual radiation level in most areas can be reduced to 2.5 lSv/h.The annual dose for radiation therapists coming from the residual radiation is 1 mSv,which is 20%of the target design.In general,this shielding design ensures a low cost and compact facility compared with the cyclotron-based PT system.
文摘Radiation for targeting liver tumors can be challenging because of the damage that it can cause to sensitive organs such as heart and kidney.To calculate the dose received by noninvolved organs,a modeling of the patient’s entire body is necessary.Therefore,in this study,a human Oak Ridge National Laboratory-Medical Internal Radiation Dose phantom was used for liver proton therapy simulation.The results show that the optimum proton energy interval covering the whole tumor was in the range of 90-120 MeV.A spread-out Bragg peak was built by adding Bragg peaks to cover the liver tumor volume,and beam parameters recommended by the International Commission on Radiation Units and Measurements(ICRU) were evaluated.The flux of secondary particles was calculated on the surface of the tumor,and two-dimensional dose distributions for protons,neutrons and photons were shown.Finally,the total doses of protons,photons and neutrons in tumor and 14 noninvolved organs were calculated.The results indicated that the ratio of received dose to the normal tissue of the liver concerning the spherical tumor of 2 cm in radius was approximately0.01.This ratio for organs such as gall bladder,heart and kidney was approximately 8.4×10-5,5.1×10-5 and2.34×10-5.Secondary particles such as neutrons andphotons deposit their energies to organs located far from the treatment volume,thus increasing the risk of secondary cancers.The research results indicated that the secondary particles dose was quite small in liver proton therapy.All the calculations were performed using Monte Carlo N-Particle Transport Code (MCNP).
