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Abstract Objective: To measure the potential radiation dose emitted by patients who have recently undergone diagnostic nuclear medicine procedures, in order to establish optimal radiation safety measures for such procedures. Materials and Methods: We evaluated the radiation doses emitted by 175 adult patients in whom technetium-99m, iodine-131, and fluorine-18 radionuclides were administered for bone, kidney, heart, brain, and whole-body scans, as measured with a radiation detector. Those values served as the basis for evaluating whole-body radiopharmaceutical clearance, as well as the risk for the exposure of others to radiation, depending on the time elapsed since administration of the radiopharmaceutical. Results: The mean time to clearance of the radiopharmaceuticals administered, expressed as the effective half-life, ranged from 1.18 ± 0.30 h to 11.41 ± 0.02 h, and the mean maximum cumulative radiation dose at 1.0 m from the patients was 149.74 ± 56.72 µSv. Even at a distance of 0.5 m, the cumulative dose was found to be only half and one tenth of the limits established for exposure of the general public and family members/caregivers (1.0 mSv and 5.0 mSv per episode, respectively). Conclusion: Cumulative radiation doses emitted by patients immediately after diagnostic nuclear medicine procedures are considerably lower than the limits established by the International Commission on Radiological Protection and the International Atomic Energy Agency, and precautionary measures to avoid radiation exposure are therefore not required after such procedures.
Resumo Objetivo: O objetivo deste trabalho foi levantar o potencial de dose de radiação emitida por pacientes em procedimentos diagnósticos, visando a estabelecer cuidados de radioproteção mais otimizados. Materiais e Métodos: Taxas de dose de radiação emitidas por 175 pacientes administrados com os radionuclídeos 99mTc, 131I e 18F para cintilografias óssea, renal, cardíaca, cerebral e corpo inteiro, foram mensuradas com um detector de radiação, servindo para avaliar o clareamento do radiofármaco no organismo e risco de exposição após administração dos radiofármacos. Resultados: O clareamento, representado pela meia-vida efetiva, variou de 1,18 ± 0,30 h até 11,41 ± 0,02 h e a dose de radiação máxima acumulada oferecida pelos pacientes a 1,0 m foi de 149,74 ± 56,72 µSv. Mesmo para distâncias de 0,5 m, as doses estimadas foram, respectivamente, duas e dez vezes inferiores ao nível de restrição para o público geral (1,0 mSv) e exposição médica (5,0 mSv/episódio). Conclusão: Doses de radiação oferecidas por pacientes em procedimentos diagnósticos são inferiores aos níveis de restrição recomendados pela International Commission on Radiological Protection e International Atomic Energy Agency, e assim, cuidados de radioproteção são geralmente desnecessários.
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At present, hepatic resection (HR) and radiofrequency ablation of (RFA) are the main radical treatment methods for small hepatocellular carcinoma (sHCC), while stereotactic body radiotherapy (SBRT) is developing rapidly and there is an increasing number of reports on the effective treatment of sHCC with SBRT. This article introduces the technical advantages, therapeutic dose, and fractionation scheme of SBRT in the treatment of sHCC, as well as the limit of normal liver tissue and the protection of surrounding organs at risk. This article also compares the efficacy of SBRT versus HR and RFA in the treatment of sHCC and briefly describes the adverse reactions of SBRT in the treatment of sHCC. Previous studies have shown that for some sHCC cases, SBRT has an equal or even better clinical effect than HR and RFA, with controllable toxicity. Therefore, SBRT is expected to become another radical treatment method for sHCC.
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Objective:To compare the dosimetric difference between volumetric modulated arc therapy (VMAT) plans with flattening filter (FF) and flattening filter-free (FFF) for whole-breast radiation therapy after breast conserving surgery for left breast cancer.Methods:Twenty patients with left breast cancer who underwent breast conserving surgery in Xuzhou Central Hospital from August 2017 to August 2018 were selected by random number table method, and the CT data were obtained. Both FF-VMAT plan and FFF-VMAT plan were designed with ECLIPSE 10.0.4 treatment planning system (TPS) of American Varian company. The prescription dose of the planned target volume (PTV) was 50 Gy (2 Gy/time), and the local tumor bed was irradiated with 10 Gy/5 times. The dosimetric parameters of the two plans were compared.Results:The two plans of all patients met the prescription dose requirements. Compared with FF-VMAT plan, FFF-VMAT plan had better conformity (conformal index: 0.87±0.04 vs. 0.77±0.05) and homogeneity (homogeneity index: 7.36±0.88 vs. 10.89±3.00) (both P < 0.01); FFF-VMAT plan had lower average dose of heart [(7.73±1.44) Gy vs. (9.16±4.24) Gy] and contralateral lung [(3.61±0.74) Gy vs. (8.42±0.45) Gy] (both P < 0.01), FFF-VMAT plan had higher average dose of contralateral breast [(3.92±1.08) Gy vs. (2.02±1.42) Gy] ( P < 0.01), and V 2 Gy in the heart [(79.27±1.18)% vs. (58.94±21.25)%] and V 5 Gy in the ipsilateral lung [(44.89±2.17)% vs.(37.86±8.33)%] (all P < 0.01). The monitor unit of the FF-VMAT plan was (973±89) MU, which was lower than that of the FFF-VMAT plan [(1 356±201) MU] ( P < 0.01). Conclusion:FFF-VMAT plan can effectively reduce the cardiac dose after breast conserving surgery for left breast cancer, but it increases the risk of organ damage at low dose area.
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Objective@#To investigate the feasibility and dosimetric characteristics of using dual-arc volumetric modulated arc therapy and multiple partial-arc VMAT for T3 lung cancer.@*Methods@#From June 2016 to May 2018, thirteen lung cancer patients with large planning target volume were replanned with dual full arcs VMAT(F-VMAT) and six partial-arc s VMAT(P-VMAT)on RayStation v4.5 RayArc function.PTV volume median was 550.9cm3(ranged 402.2-834.8cm3) and to a prescribed dose of 60 Gy in 30 fractions.Equivalent target coverage was required for all plans, and clinical goals were evaluated using various dose-volume metrics.These included PTV dose conformity, mean lung/heart dose, lung V5, V10, V20, V30, heart V30 and V40, and Dmax of spinal canal.The total monitor units (MUs) were also examined.@*Results@#All VMAT plans satisfied the treatment criteria.F-VMAT achieved better homogeneity index(HI) and MUs than P-VMRT(t=-3.904, P=0.002), and the conformal number(CN) of tumor volumes was likely clinically indistinguishable.However, F-VMAT significantly reduced lung V5, V10 and mean lung dose[V5: (51.31±5.36)% vs.(43.44±5.28)%, t=6.908, P=0.00; V10: (38.34±3.26)% vs.(34.05±3.74)%, t=4.632, P=0.001; Dmean: (1 449±117.19)cGy vs.(1 375.38±148.98)cGy, t=4.93, P=0.00], and heart dosimetric parameters were also observed in favor of P-VMRT[V30: (20.6±10.4)% vs.(16.4±8.9)%, t=3.822, P=0.02; V40: (14.6±7.5)% vs.(11.88±7.1)%, t=3.096, P=0.009; Dmean: (1 442.9±651.2)cGy vs.(1 263.5±605.6)cGy, t=3.986, P=0.02], and there were no statistically significant differences in lung V20, V30 and spinal cord Dmax between the two groups(all P>0.05).@*Conclusion@#VMAT is an effective treatment for stage T3 lung cancer patients.The primary advantage of P-VMAT was the reduction in low dose area and decreased risk of symptomatic radioactive lung injury.It may be a priority for pulmonary malignancy patients with the large planning target volume.
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Objective@#To investigate clinical application of self-designed organ traction bag in male genital immobilization during radiotherapy.@*Methods@#The male patients in the Department of Radiation Oncology, Suzhou Municipal Hospital from August 2018 to June 2019 were immobilized by using organ traction bag. Clinical effect was evaluated by subjective and objective ways which were the location relationship between contents and reference field under visual observation and fluoroscopy, and setup errors by CBCT images.@*Results@#A total of 11 patients were selected, including 3 seminoma, 2 low rectal carcinoma, 2 prostatic carcinoma, 4 pelvic lymph nodes and bone metastases, with mean age 57.18 years old. Patients received 273 times of treatment and 55 times of CBCT verifications in all. Analysis results that the setup errors of the whole group in upper and lower (Vrt), head and foot (Lng), left and right (Lat) directions are less than 0.5 cm, within acceptable clinical threshold. The contents under visual observation and fluoroscopy were not in reference field and were fixed well.@*Conclusions@#Organ traction bag provides stable effect on male genital immobilization while taking patients’ privacy and clinical operability into account. It has high clinical application value in radiotherapy involving male genital protection.
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Objective@#To compare the ablation efficacy and therapy response with 1.1 GBq and 3.7 GBq 131I in postoperative patients with low- and intermediate-risk differentiated thyroid carcinoma(DTC).@*Methods@#A total of 190 patients (43 males, 147 females, age: (45.8±11.1)years) were enrolled from July 2016 to July 2017. Among them, 96 patients received 1.1 GBq 131I and 94 were given 3.7 GBq 131I. Diagnostic whole-body scan was performed 6 months after 131I ablation for treatment response evaluation, and the successful rate of 131I ablation was calculated. χ2 test or Fisher′s exact test was used for data analysis. The cut-off value of 99Tcm-pertechnetate uptake for predicting the successful rate of remnant thyroid ablation in 1.1 GBq group was determined by receiver operating characteristic (ROC) curve analysis.@*Results@#The successful ablation rates in 1.1 GBq and 3.7 GBq groups were 79.2%(76/96) and 81.9%(77/94), respectively (χ2=0.229, P>0.05). There was no significant difference in the therapy response between the two groups (χ2=1.371, P>0.05). The successful ablation rate in 3.7 GBq group was higher than that in 1.1 GBq group for patients with stage Ⅲ (5/6 vs 1/7, P=0.029). Moreover, for patients with 5 μg/L<preablative-stimulated thyroglobulin (ps-Tg)≤10 μg/L, the ablation rate in 1.1 GBq group was lower than that in 3.7 GBq group (3/11 vs 10/13, P=0.038). ROC curve analysis showed the cut-off value of 99Tcm-pertechnetate uptake for prediction of the successful ablation rate in 1.1 GBq group was 0.061 5.@*Conclusion@#The low- and intermediate-risk DTC patients with stage Ⅲ disease, 5 μg/L<ps-Tg≤10 μg/L or higher 99Tcm-pertechnetate uptake of remnant thyroid should be given 3.7 GBq other than 1.1 GBq 131I to obtain a better ablation efficacy.
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Objective To compare the ablation efficacy and therapy response with 1. 1 GBq and 3. 7 GBq 131I in postoperative patients with low- and intermediate-risk differentiated thyroid carcinoma (DTC). Methods A total of 190 patients (43 males, 147 females, age:(45.8±11.1)years) were enrolled from July 2016 to July 2017. Among them, 96 patients received 1.1 GBq 131I and 94 were given 3.7 GBq 131I. Diagnostic whole-body scan was performed 6 months after 131 I ablation for treatment response evaluation, and the successful rate of 131I ablation was calculated. χ2 test or Fisher's exact test was used for data analysis. The cut-off value of 99 Tcm-pertechnetate uptake for predicting the successful rate of remnant thyroid ablation in 1.1 GBq group was determined by receiver operating characteristic ( ROC) curve analysis. Results The successful ablation rates in 1.1 GBq and 3.7 GBq groups were 79.2％(76/96) and 81.9％(77/94), respec-tively (χ2=0.229, P>0.05). There was no significant difference in the therapy response between the two groups (χ2=1.371, P>0.05) . The successful ablation rate in 3.7 GBq group was higher than that in 1.1 GBq group for patients with stageⅢ(5/6 vs 1/7, P=0.029). Moreover, for patients with 5μg/L<preablative-stimula-ted thyroglobulin (ps-Tg)≤10μg/L, the ablation rate in 1.1 GBq group was lower than that in 3. 7 GBq group ( 3/11 vs 10/13, P=0.038) . ROC curve analysis showed the cut-off value of 99 Tcm-pertechnetate uptake for prediction of the successful ablation rate in 1.1 GBq group was 0. 0615. Conclusion The low- and inter-mediate-risk DTC patients with stageⅢdisease, 5μg/L<ps-Tg≤10μg/L or higher 99 Tcm-pertechnetate up-take of remnant thyroid should be given 3.7 GBq other than 1.1 GBq 131I to obtain a better ablation efficacy.
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Objective To investigate the feasibility and dosimetric characteristics of using dual - arc volumetric modulated arc therapy and multiple partial-arc VMAT for T3 lung cancer.Methods From June 2016 to May 2018,thirteen lung cancer patients with large planning target volume were replanned with dual full arcs VMAT (F-VMAT) and six partial-arc s VMAT( P-VMAT) on RayStation v4.5 RayArc function.PTV volume median was 550.9cm3(ranged 402.2-834.8cm3 ) and to a prescribed dose of 60 Gy in 30 fractions.Equivalent target coverage was required for all plans,and clinical goals were evaluated using various dose-volume metrics.These included PTV dose conformity,mean lung/heart dose,lung V5 ,V10 ,V20 ,V30 ,heart V30 and V40 ,and Dmax of spinal canal.The total monitor units ( MUs) were also examined. Results All VMAT plans satisfied the treatment criteria. F - VMAT achieved better homogeneity index ( HI) and MUs than P -VMRT( t = -3.904,P =0.002),and the conformal number(CN) of tumor volumes was likely clinically indistinguishable.However,F-VMAT significantly reduced lung V5 ,V10 and mean lung dose[V5:(51.31 ± 5.36)% vs.(43.44 ± 5.28)%,t=6.908,P=0.00;V10:(38.34 ± 3.26)% vs.(34.05 ± 3.74)%,t=4.632,P=0.001;Dmean:(1 449 ± 117.19)cGy vs.(1 375.38 ± 148.98)cGy, t=4.93, P =0.00 ], and heart dosimetric parameters were also observed in favor of P - VMRT [ V30 : (20.6 ± 10.4)% vs.(16.4 ± 8.9)%,t =3.822,P =0.02;V40:(14.6 ± 7.5)% vs.(11.88 ± 7.1)%,t =3.096,P =0.009;Dmean:(1 442.9 ± 651.2)cGy vs.(1 263.5 ± 605.6)cGy,t=3.986,P=0.02],and there were no statisti-cally significant differences in lung V20,V30 and spinal cord Dmax between the two groups(all P>0.05).Conclusion VMAT is an effective treatment for stage T3 lung cancer patients. The primary advantage of P - VMAT was the reduction in low dose area and decreased risk of symptomatic radioactive lung injury.It may be a priority for pulmonary malignancy patients with the large planning target volume.
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For resectable elderly esophageal cancer,neoadjuvant chemoradiotherapy combined with surgery is still the preferred treatment under the condition of fully measuring the patient's physical function.Definitive chemoradiation is the first choice for patients with inoperable esophageal cancer,and may be a good alternative for elderly operable patients with good response to tumor regression.For older patients (＞80 years old),radiotherapy alone may be mild and conservative enough to be the preferred option.At the same time,compared with conventional radiation dose (50.4 Gy),selective regional lymph node irradiation,standard PF regimen (cisplatin + 5-fluorouracil),radiotherapy of high dose (≥60 Gy),involving field irradiation combined with single-drug chemotherapy (such as tegio) can bring better prognosis.
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PURPOSE: The effectiveness of thoracic radiation therapy (TRT) in extensive-stage small cell lung cancer (ES-SCLC) patients is increasingly reported, but there is no definite consensus on its application. The aim of this study was to identify factors associated with better outcomes of TRT among patients with ES-SCLC, focusing on whether a higher TRT dose could improve treatment outcome. MATERIALS AND METHODS: The medical records of 85 patients with ES-SCLC who received TRT between January 2008 and June 2017 were retrospectively reviewed. Eligibility criteria were a biological effective dose with α/β = 10 (BED) higher than 30 Gy₁₀ and completion of planned radiotherapy. RESULTS: During a median follow-up of 5.3 months, 68 patients (80.0%) experienced disease progression. In univariate analysis, a BED >50 Gy₁₀ was a significant prognostic factor for overall survival (OS; 40.8% vs. 12.5%, p = 0.006), progression-free survival (PFS; 15.9% vs. 9.6%, p = 0.004), and intrathoracic PFS (IT-PFS; 39.3% vs. 20.5%, p = 0.004) at 1 year. In multivariate analysis, a BED >50 Gy₁₀ remained a significant prognostic factor for OS (hazard ratio [HR] = 0.502; 95% confidence interval [CI], 0.287–0.876; p = 0.015), PFS (HR = 0.453; 95% CI, 0.265–0.773; p = 0.004), and IT-PFS (HR = 0.331; 95% CI, 0.171–0.641; p = 0.001). Response to the last chemotherapy was also associated with better OS in both univariate and multivariate analysis. CONCLUSION: A TRT dose of BED >50 Gy₁₀ may be beneficial for patients with ES-SCLC. Further studies are needed to select patients who will most benefit from high-dose TRT.
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Humans , Consensus , Disease Progression , Disease-Free Survival , Drug Therapy , Follow-Up Studies , Medical Records , Multivariate Analysis , Radiotherapy , Radiotherapy Dosage , Retrospective Studies , Small Cell Lung Carcinoma , Treatment OutcomeABSTRACT
PURPOSE: To evaluate clinical outcomes according to radiation dose in patients with limited-stage small-cell lung cancer (LS-SCLC) treated with concurrent chemoradiotherapy (CCRT). MATERIALS AND METHODS: From January 2006 to December 2015, 38 patients with LS-SCLC were treated with CCRT with etoposide and cisplatin. Total radiation doses ranged from 45 Gy to 66 Gy (1.8–2 Gy/fraction) and were classified into three groups: 45–54 Gy, 60–63 Gy, and 66 Gy. The impact of radiation dose on survival outcomes were evaluated. Toxicities were evaluated according to the Common Terminology Criteria for Adverse Events version 4.03. RESULTS: The median follow-up period was 21 months. The 2-year overall survival (OS) and local failure-free survival (LFFS) rates were 45.8% and 67.5%, respectively. The 2-year LFFS rates were 33.3% for 45–54 Gy group, 68.6% for 60–63 Gy group, and 87.1% for 66 Gy group (p = 0.014). In multivariate analysis, radiation dose was a significant factor for LFFS (p = 0.015). Although radiation dose was not a significant factor for OS and disease-free survival (DFS) in multivariate analysis, both OS and DFS of 66 Gy group tended to be better than that of 45–63 Gy group in univariate analysis. However, there were no differences in severe toxicities among three groups. CONCLUSION: Higher radiation dose achieved better local control in patients with LS-SCLC treated with CCRT. In addition, a total dose of 66 Gy tended to improve OS and DFS.
Subject(s)
Humans , Chemoradiotherapy , Cisplatin , Disease-Free Survival , Etoposide , Follow-Up Studies , Lung Neoplasms , Lung , Multivariate Analysis , Radiotherapy Dosage , Small Cell Lung CarcinomaABSTRACT
Objective To analyze the correlation between treatment time and radiotherapy plan of deep inspiration breath-hold (DIBH) technique for the whole breast irradiation (WBI) in the left breast cancer after breast-conserving surgery,verify the inter-fractional reproducibility of radiotherapy,observe the heart location and dosimetric changes and calculate the effect of DIBH upon the WBI setup error after the surgery.Methods We prospectively enrolled 15 patients with left breast cancer undergoing WBI after breast-conserving surgery,who met the requirement of D1BH.Treatment time was recorded,its correlation with the number of field and monitor unit was analyzed.Inter-fractional setup errors and PTV delineation were calculated using cone beam CT (CBCT).The accuracy of the position and dose of the heart during radiotherapy was verified by the imaging fusion of CBCT and CT images.The variables among groups were analyzed by non-parametric Firedman test.Results The average treatment time of DIBH radiotherapy was 4.6 minutes.The treatment time was correlated with the maximal and total number of sub-fields and total monitor units.During DIBH treatment,the mean cardiac displacement volume was 19.1 cm3(3.8％).The mean cardiac dose difference between CBCT and planning CT was 5.1 cGy,and there was no significant difference in the heart V5-V30.The mean inter-fractional system setup error (∑) and random setup error (σ) in the left-right (x),superior-inferior (y) and anterior-posterior (z) direction were ∑x 1.9 mm,∑y 2.1 mm,∑z 2.0 mm,σx 1.3 mm,σy 1.3 mm,σz 1.4 mm,respectively.The corresponding minimal margins for setup error were 5.7 mm,6.2 mm and 6.0 mm,respectively.Conclusion DIBH for WBI after breast-conserving surgery does not significantly prolong the treatment time.Treatment time is related to treatment plan.DIBH yields high inter-fractional reproducibility and protects the heart.
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Objective To investigate the occurrence and degree of radiation-induced injury in vagina after radical radiotherapy of cervical cancer.Methods A total of 282 cases of patients with cervical cancer were collected from November 2016 to September 2017.All of the above patients underwent radical radiotherapy from 2008 to 2017 in the First Affiliated Hospital of Xi′an Jiaotong University.The patients′International Federation of Gynecology and Obstetrics(FIGO)staging(2009),brachytherapy dose,whether receive synchronous chemotherapy or not,age and body mass index(BMI)for the occurrence and severity of vaginal radiation injury at different time periods were analyzed by cross-sectional survey method.The single factor would be analyzed by the method of Chi-square test and the multiple factors would be analyzed by logistic regression method to checkout. Results Of the 282 patients, the incidence of radiation-injury in vaginal was 84.4%(238/282), with the incidence rate of degree Ⅰ,Ⅱ and Ⅲradiation injury were respectively 50.7%(143/282),29.8%(84/282)and 3.9%(11/282;χ2=153.375,P<0.05),and there was no degree Ⅳ. Until the end of the follow-up time, the incidence of radiation-induced injury in vaginal after completing the treatment within 1 year,1-2 years,>2-<5 years and≥5 years were respectively 80.0%(24/30), 87.2%(102/117), 88.2%(60/68)and 77.6%(52/67; χ2=4.231, P=0.238). There were 30 cases be followed within 1 year after treatment,the incidence rate of degreeⅠ,ⅡandⅢof radiation injury in vagina was 60.0%(18/30), 20.0%(6/30)and 0, respectively (χ2=28.636, P<0.05). There were 117 cases be followed between 1- 2 years after treatment, the incidence rate of degree Ⅰ, Ⅱ and Ⅲ vaginal radiation-induced injury were 54.7%(64/117),29.9%(35/117)and 2.6%(3/117),respectively(χ2=77.198, P<0.05).There were 68 cases be followed between>2-<5 years after treatment,the incidence rate of degreeⅠ,Ⅱ and Ⅲ vaginal radiation-induced injury were 51.5%(35/68),33.8%(23/68)and 2.9%(2/68), respectively(χ2=39.525,P<0.05).There were 67 cases be followed≥5 years after treatment,the incidence rate of degreeⅠ,ⅡandⅢvaginal radiation injury were 38.8%(26/67),29.9%(20/67)and 9.0%(6/67), respectively(χ2=16.395, P<0.05). The single-factor analysis result indicated that the brachytherapy dose had an obvious effect on vaginal radiation-induced injury(χ2=5.344,P=0.021);however,other factors,such as age, BMI, FIGO stages and synchronous chemotherapy, had no obvious effect on vaginal radiation-induced injury(all P>0.05). The multifactor analysis indicated that the brachytherapy dose was an independent factor affecting the occurrence of vaginal radiation-induced injury(P=0.043). Conclusion After the radical radiotherapy of cervical cancer, the vaginal radiation-induced injury is associated with the dose of brachytherapy.
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Objective@#To compare the dosimetric differences in forward intensity-modulated radiotherapy using field-in-field (FIF-F-IMRT) and inverse intensity-modulated radiotherapy (I-IMRT) for the left-sided breast cancer.@*Methods@#A total of 18 patients with left-sided breast cancer undergoing breast-conserving surgery in Shanxi Provincial People's Hospital from January to July 2015 were enrolled. For each patient, two treatment plans were designed. The plans were compared by means of target dose distribution and dose for organ at risk.@*Results@#The two methods met the requirements of the prescribed doses. There were no differences for maximal dose (Dmax), mean dose (Dmean), and 100%, 105%, 110% prescription dose percent volume (V100, V105, V110) of the target (all P > 0.05). The percentage volume of heart receiving 5 Gy (V5), 20 Gy (V20), 30 Gy (V30), Dmean of heart of FIF-F-IMRT [(11±4)%, (7±4)%, (8±3)%, (15±3) Gy] were lower than those of I-IMRT [(42±8)%, (14±10)%, (14±4)%, (18±7) Gy] (t values were 29.457, 5.542, 5.064, 4.165, all P = 0.000). V5 of left-sided lung of FIF-F-IMRT [(26±6)%] was lower than that of I-IMRT [(47±12)%] (t = 6.708, P = 0.000), but there was no significant difference between the two groups in V20, V30, V40, Dmean of left-sided lung (all P≥0.05). V5 of right-sided lung and right-sided breast, Dmean of right-sided lung of FIF-F-IMRT [(7±4)%, (26±5)%, (60±19) Gy] were lower than those of I-IMRT [(31±9)%, (48±11)%, (489±67) Gy] (t values were 12.304, 6.708, 42.489, all P = 0.000). The number of the monitor units and spending time of FIF-F-IMRT were lower than those of I-IMRT (t values were 12.214 and 29.899, both P = 0.000).@*Conclusion@#FIF-F-IMRT has a good dose distribution in the target volume, and could reduce the dose for organ at risk, especially reduce the unnecessary low dose irradiation, and consume less planning time and equipment consumption.
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Objective: To explore the importance of distinguishing α/β values for different lung cancer cells based on driver genes and its significance in the precise radiotherapy. At the same time, to study the influence of serine/threonine kinase inhibitor MK1775 on the α/β values for different kinds of cells, and to investigate the radiation sensitization or synergistic effect of MK1775. Methods: Lung cancer PC9 cells with epidermal growth factor receptor (EGFR) gene mutant, A549 cells with V-Ki-ras2-Kirsten rat sarcoma viral oncogene homolog (K-RAS) gene mutant, and H1299 cells with p53 gene mutant were respectively cultured and assigned into three groups: the control group, radiation alone group, and MK1775 inhibitor combined with radiation group. 6 MV X-ray with a dose rate of 3 Gy/min was employed in all the radiation groups, in which the administered dosages were 0, 0.25, 0.5, 1, 2, 3, 4, 5 and 6 Gy, respectively. Finally, the dose-effect relationship was analyzed by employing clone counting method, and the radiosensitization and synergistic effects of MK1775 on the three kinds of gene mutant cells were analyzed. Results: The different gene mutation types corresponded to different hyper-radiosensitivity doses. The numbers of PC9, A549 and H1299 cell clones were decreased to 56.4%, 54.5% and 73.2% respectively after adding MK1775 inhibitor, which indicated that the synergy effect exists indeed between MK1775 and radiation. The α/β values were negative in PC9 and H1299 cells (except of A549 cells) before MK1775 treatment, and all the α/β values in PC9, H1299 and A549 cells in MK1775 combined with radiation group were positive. So it was indicated that the radiosensitizing effect of MK1775 inhibitor only worked when α/β value was negative. Additionally, there was significant difference between the radiation alone group and MK1775 combined with radiation group (P < 0.05). Conclusion: The different driver genes correspond to different α and β values, thus correspond to different equivalent biological doses. Simultaneously, MK1775 maybe have the different radiosensitization or radiosynergistic effect for lung cancer cells with different driver genotypes.
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Objective To compare the effect between the supine and prone patient positions upon target dose coverage during intensity-modulated radiotherapy (IMRT) for rectal cancer, aiming to provide clinical reference for the selection of position for rectal cancer patients. Methods Twenty-four patients diagnosed with rectal cancer receiving postoperative adjuvant radiotherapy were selected and divided into the supine (n=12) and prone position groups(n=12). Before and during the IMRT(1-4 weeks),all patients received CT scans, which were defined as:Plan,1W,2W,3W and 4W,respectively. The organs at risk were delineated based on CT scan images. Plan,1W, 2W, 3W and 4W CT scan images were fused. The CTV and PTV from Plan CT scan were copied to the 1-4W CT scan images,and the therapeutic plans from Plan CT scan were copied as well. The target dose coverage was assessed and the failure rate of target dose coverage was calculated. The couch-position data for each patient during each cycle of IMRT were recorded by using the MOSAIQ network and the overall deviation (S) of couch position was calculated. Results The failure rates of CTV and PTV target dose coverage in the prone position group were higher than those in the supine position group (18.60% VS 0%, 69.76% VS 53.65%).The S value was significantly correlated with the target dose coverage (r=-0.683,P=0.000). The S value in the prone position group was(1.23±0.76) cm,significantly greater than(0.28±0.18) cm in the supine position (P=0.001),and the most significant deviation was noted in the y (head and foot) and z (frontal and dorsal) directions (P=0.003 and 0.003). Compared with the supine group,the V5and V10 of the small intestine were significantly less (P=0.003 and 0.004) and the chronic toxicity (NTCPC) was considerably reduced(P=0.041) in the prone position group. Conclusions A better target dose coverage can be maintained during IMRT with a supine position during rectal cancer IMRT, whereas the positioning repeatability is worsened with a prone position due to use of the belly board, thereby affecting the target dose coverage. Although the prone position combined with belly board can reduce the tolerated dosage of the small intestine,effective measures should be taken to guarantee the patient positioning repeatability.
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Objective To analyze the radiation doses to the head, body, and tail of the hippocampus in intensity-modulated radiotherapy(IMRT)for nasopharyngeal carcinoma(NPC). Methods Ten NPC patients treated with IMRT were selected,and the head, body, and tail of both hippocampi were delineated on T1-weighted images. The doses to the hippocampus were then analyzed. WAIS-CR speech test results were tested by paired sample t-test. Results The mean doses to left and right hippocampi were 1 147±976 cGy and 1 011±602 cGy, respectively. The mean doses to the head, body, and tail of the left hippocampus were 1 739± 1 317 cGy, 890± 982 cGy, and 547± 688 cGy, respectively(P=0.042);the mean doses to the head,body,and tail of the right hippocampus were 1 691±942 cGy,744±483 cGy,and 531±603 cGy,respectively(P=0.002).The dose to the hippocampus decreased from the head to the tail, and the irradiated volume also decreased as the dose varied. Conclusions The dose to hippocampus decreases from the head to the tail in NPC patients treated with IMRT,which is worthy of attention.
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Objective: To compare the dosimetric data between the preoperative plans and postoperative verification in personalized 3D printed template-assisted and computed tomography (CT) image-guided 125-iodine seed implantation for supraclavicular metastatic tumor, and to evaluate the accuracy and feasibility at the dosimetry level.Methods: A total of 14 patients with supraclavicular metastatic tumor (including 15 lesions) who received 3D printed template assisted and CT image-guided 125-iodine seed implantation in Department of Radiation Oncology of Peking University Third Hospital from January to September 2016 were enrolled.There were 8 males and 6 females, aged from 46 to 79 years (mean age: 59.9 years).The Karnofsky performance score (KPS) was from 60 to 90 (median of 80).There were one patient who had not received radiotherapy before, and one patient had received radiotherapy, but the dose was unknown.The remaining 12 patients had received radiotherapy, with the median of 60 Gy (20-70 Gy), and one of them with the dose unknown.All the patients underwent preoperative enhanced CT scan, preoperative planning design, 3D printing template, puncture and particle implantation, the prescription dose from 110 Gy to 150 Gy.Comparisons of the dosimetric parameters between the postoperative verification and preoperative plans were made by paired t-test.The dose parameters inclu-ded D90, V100, V150, V200, matched peripheral dose (mPD), conformal index (CI), and external index (EI).The agreement was evaluated between the preoperative planning and postoperative actual dose parameters using Bland-Altman analysis.Bland-Altman plot showed the difference against the average of preoperative planning and postoperative actual dose parameters with limits of agreement (LoA) (broken lines).Results: The difference of all the data between pre-and postoperation, included D90, V100, V150, V200, mPD, and CI, which was not statistically significant (P>0.05).EI was statistically significant (P<0.05).There was poor consistency of D90, V100, V150, V200, and mPD, but better consistency of CI and EI.Conclusion: Personalized 3D printed template-assisted and CT image-guided 125-iodine seed implantation for supraclavicular metastatic tumor is accurate and feasible.
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Objective To study the biological effect of different dose of satereotactic body radiation therapy (SBRT) on hepatoma Hep G2 Cells.Methods Hep G2 hepatumor cells vitality of 0,2,4,6,8,and 10 Gy doses of SBRT were determined by methyl thiazolyl tetrazolium (MTT) method.The cell colony formation rate and the cell survival fraction were detected.The cell apoptosis was detected by flow cytometry.The expressions of cyclin D1,Bax,Bcl-2,and caspase-3 protein were detected by Western blot.Results Hep G2 cells vitality was obvious inhibitory effect in different doses of SBRT,increasing with the SBRT dose,the cell vitality inhibition [2 Gy group (4.29 ± 0.63) ％,4 Gy group (19.37 ± 4.54) ％,6 Gy group (41.35 ±4.51)％,8 Gy group (86.34 ±5.68)％,10 Gy group (97.24 ±5.41)％] was increased,compared to 0 Gy group [(2.94 ± 0.52) ％],the difference was statistically significant (all P ＜ 0.01 or P ＜0.05).The cell colony formation rate and survival score in different doses of SBRT were statistically lower than the control group,increasing with the SBRT dose,the cell colony formation rate [4 Gy group (83.15 ± 4.71),6 Gy group (65.23 ± 5.47),8 Gy group (41.28 ± 5.36),10 Gy group (8.14 ± 5.22)] and survival score [2 Gy group (95.49 ±3.21),4 Gy group (84.23 ±3.45),6 Gy group (66.08 ± 3.71),8 Gy group (41.82 ± 3.82),10 Gy group (8.25 ± 3.56)] were decreased,compared to 0 Gy group [(98.72 ± 1.23),(100.00 ±0.00)],the differences were statistically significant (all P ＜0.01 or P ＜ 0.05).The cell apoptosis in different doses of SBRT was increased,increasing with the SBRT dose,the Hep G2 cells apoptosis [4 Gy group (13.67 ±4.62),6 Gy group (28.71 ±5.13),8 Gy group (54.16 ±5.24),10 Gy group (76.31 ± 5.17)] were significantly increased,compared to 0 Gy group (1.35 ±0.46),the difference was statistically significant (all P ＜ 0.01).The expressions of cyclinD1,Bax,Bcl-2,and caspase-3 protein in different doses of SBRT were decreased,increasing with the SBRT dose,the cyclin D1 [6 Gy group (1.94 ± 0.57),8 Gy group (1.38 ± 0.41),10 Gy group (0.52 ± 0.34)],Bax[6 Gy group (2.67 ±0.59),8 Gy group (1.73 ±0.45),10 Gy group (0.63 ±0.37)],Bcl-2 [4 Gy group (1.78 ±0.41),6 Gy group (1.03 ±0.35),8 Gy group (0.76 ±0.28),10 Gy group (0.38 ± 0.21)],Caspase-3 [6 Gy group (0.76 ± 0.31),8 Gy group (0.42 ± 0.24),and 10 Gy group (0.24 ± 0.21)] were obviously decreased,compared to 0 Gy group [(3.41 ± 0.75),(4.36 ± 0.87),(2.57 ± 0.46),(1.67 ± 0.55)],the difference was statistically significant (all P ＜ 0.05).Conclusions Different dose of SBRT can reduce Hep G2 cell vitality,enhance radiation sensitivity,have a dose dependent,maybe related to promote cell apoptosis and inhibit the proliferation of protein expression.
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Objective To study the biological effects of dose radiotherapy for primary liver cancer patients with stereotactic body portion.Methods 80 patients with primary liver cancer were selected.According to a random number table method, all patients were divided into observation group and control group,40 patients in each group.All patients were treated with stereotactic body radiotherapy treatment, the observation group was treated with high dose, while the control group received low-dose.The radiotherapy effects of different doses were analyzed and compared.Results After treatment, the effective rate of the observation group was 77.5%,which of the control group was 55.0%, ,the difference between the two groups was statistically significant (x2=4.528,P=0.033).After treatment for 6 months,1 year and 2 years, the survival rates of the observation group were 77.5%,75.0%,72.5%, which were significantly higher than 55.5%,52.5%,50.0% of the control group (P<0.05).The incidence rate of adverse reactions of the observation group was 42.5%, which was significantly lower than 72.5% of the control group (x2=7.365,P=0.006).Conclusion Stereotactic body radiotherapy treatment with different therapeutic dose has different treatment efficacy, high-dose SBRT treatment has significantly higher efficacy, survival rate and lower adverse reactions, which is worthy of clinical application.