Prognostic significance of lactate dehydrogenase in salvage intensity-modulated radiotherapy for locally recurrent nasopharyngeal carcinoma before treatment / 中国耳鼻咽喉头颈外科

OBJECTIVE To investigate the prognostic value of pre-treatment serum lactate dehydrogenase(LDH)levels in patients with locally recurrent nasopharyngeal carcinoma(NPC)treated with salvage intensity-modulated radiotherapy(IMRT)and to determine its association with rT staging.METHODS The records of 97 patients with locally relapsed and non-metastatic NPC who received salvage IMRT treatment in our center from January 2018 to April 2022 were collected,including 51 patients who died,18 patients with distant metastases,30 patients with local failure,and 67 patients with prognostic adverse events(death,distant tumors/local metastases).Clinical data,local failure-free survival(LFFS),distant metastasis-free survival(DMFS)and overall survival(OS)were obtained from all patients,and the relationship between LDH and the prognosis of salvage IMRT therapy in NPC patients was analyzed.RESULTS The serum LDH level before salvage IMRT was significantly higher in the death[221.25(178.24,339.13)U/L vs.124.82(79.0,159.50)U/L,Z=-5.122],local failure[230.75(170.89,394.50)U/L vs.157.85(91.78,216.95)U/L,Z=-3.442],distant metastasis[261.62(153.55,465.50)U/L vs.168.98(101.75,237.75)U/L,Z=-2.478]and poor prognosis group[220.05(167.20,506.16)U/L vs.93.45(69.95,154.35)U/L,Z=-6.018],and all P<0.05.Serum LDH levels were divided into dichotomous variables according to median values(≥177.50 U/L vs.<177.50 U/L),the Cox univariate model found that the hazard ratios of LDH affecting LFFS,DMFS,OS and toxic-related death(TRD)were 3.759(1.660-8.558),4.217(1.383-12.861),3.226(1.715-6.069),3.363(1.750-6.463),P<0.05.LDH remained an independent prognostic factor for LFFS,DMFS,OS,and TRD in multivariate regression analysis(P<0.05).Compared with patients with LDH<177.50 U/L,more patients in the LDH≥177.50 U/L group had local progression-related death,and the no LFFS stage,no DMFS stage and OS were shorter in the LDH≥177.50 U/L group(log rank=11.624,7.559,14.758),P<0.05.In predicting overall survival,adding LDH to the rT stage is preferable to the rT stage alone.CONCLUSION LDH is an important factor in predicting LFFS,DMFS,OS,and TRD after saving IMRT in patients with locally relapsed,non-metastatic NPC,and the value of LDH combined with rT staging in predicting overall survival is high.

A dosimetric study of 3D-printed individual phantom in intensity modulated radiation therapy plan for chest / 中国医学装备

Objective:To make an individual phantom that was printed by using three dimension(3D)technique,which could reflect the real situation of patient,and to analyze the computed tomography(CT)value and dose distribution of radiotherapy on each organ of the inside of the 3D-printed individual phantom.Methods:According to the localization of CT image of the patient,the empty shell of 3D structure of each organ were reconstructed and printed by using 3D technique.The CT value was used as basis to select the equivalent material of each organ to perform fill,which could obtain the individual phantom of chest that could appear the structural characteristics of patient.The treatment plan of patients were included in treatment plan group,and the plans which were transplanted to 3D-printed individual phantom from treatment plan of patients were included in phantom plan group.The dosimetric parameters of the plans of two groups were compared.Results:The average CT values of left and right lung,soft tissue,cancellous bone,compact bone and heart of the phantom plan group were respectively-709,-737,14,144,760 and 28 HU.The errors of the all CT values between phantom images and located images of patients were less than 16.7%.The exposure doses of normal tissues of radiotherapy plans on the images of two groups could meet the clinical requirements.The minimum dose(Dmin),mean dose(Dmean),the corresponding doses of 98%,50% and 2% target volumes(D98%,D50% and D2%),conformity index(CI),homogeneity index(HI),monitor unit(MU)of dosimetric parameters of the target region could meet the clinical requirements without statistically significant differences.There was significant differences in the maximum dose(Dmax)of the target region(t=2.678,P＜0.05).Among of these Dmax values,the Dmax value of phantom plan group was larger,which was(56.97±0.32)Gy.Conclusion:The CT value,tissue structure and spatial distribution of the phantom,which is finally designed,can emulate the chest of human body in radiotherapy.It has verified the feasibility that 3D-printed phantom is applied in measuring dose in the quality assurance of radiotherapy.

Research progress on the application of four-dimensional CT combined with four-dimensional cone beam CT in stereotactic radiotherapy for lung cancer / 中国医学装备

High-precision radiotherapy represented by stereotactic body radiation therapy(SBRT)plays an important role in every stage of lung cancer treatment.The development of medical imaging technology,more accurate dose calculation methods,and the application of advanced imaging and dose verification algorithms provide guarantee for the realization of high-precision radiotherapy.Four-dimensional computed tomography(4D CT)can better display the individualized motion of tumors affected by respiration.Four-dimensional cone beam computed tomography(4D-CBCT)is an image-guided technology to delineate and obtain the internal target volume(ITV),which Can provide guarantee for precise treatment.The combination of the two technologies can correct the displacement error,monitor the range of tumor motion,and ensure that the moving target is within the irradiation range,which is the guarantee of stereotactic radiotherapy.From the perspective of image-guided radiation technology in the application of precise radiotherapy for lung cancer,the clinical application value of 4D CT combined with 4D-CBCT in SBRT of tumors was reviewed,aiming to provide reference for clinical radiotherapy of lung cancer.

The changes of volume and dose in adaptive re-planning during radiotherapy for nasopharyngeal carcinoma / 中华放射肿瘤学杂志

Objective:To investigate the necessity of adaptive re-planning during radiotherapy for nasopharyngeal carcinoma (NPC) and its impact on dose improvement.Methods:Clinical data of 89 NPC patients admitted to Sun Yat-sen University Cancer Center from July 2014 to December 2017 were retrospectively analyzed. All patients received 25+7 rounds of adaptive re-planning during radiotherapy. Plan-A was defined as the initial CT scan-based 25-fraction radiotherapy plan, while plan-B was defined as the re-planned 7-fraction radiotherapy plan based on a subsequent CT scan. The changes in the target and parotid gland volumes were compared between plan-A and plan-B. Plan-I was a one-time simulation of plan-A extended to 32 fraction radiotherapy plan, and plan-II was generated through registration and fusion of the plan-A and plan-B for adaptive re-planning. The differences in dose metrics, homogeneity index (HI), conformity index (CI), and dose to organs at risk (OAR) were compared between plan-I and plan-II. Statistical analysis was performed by using paired t-test. Results:Compared with plan-A, the gross tumor volume of massive bleeding lesions (GTV nx) and parotid gland volume of plan-B were decreased by 13.14% and 11.12%, respectively (both P<0.001). While planning clinical target volume of metastatic lymph nodes (PCTV nd) of plan-B was increased by 7.75%( P<0.001). There were significant changes in the lymph nodes of plan-A and plan-B. The D mean, D 5%, D 95% of massive bleeding lesions planning target volume (PTV nx) and D 5% of high risk planning target volume (PTV1) in plan-II were all significantly higher than those in plan-I (all P<0.05). The CI of PTV nx and PTV1 in plan-II was closer to 1 than that in plan-I. In all assessed OAR, the D mean, D 50%, and D max of plan-II were significantly lower than those of plan-I (all P<0.05). Conclusions:During radiotherapy, NPC patients may experience varying degrees of primary tumor shrinkage, parotid gland atrophy, and lymph node changes. It is necessary to deliver re-planning and significantly improve the dose of target areas and OAR.

Application of precision radiotherapy in the treatment of hepatocellular carcinoma / 中华放射肿瘤学杂志

With the development of radiotherapy technology, the role of radiotherapy in the treatment of primary liver cancer has been gradually recognized. In recent years, precision radiotherapy for hepatocellular carcinoma has become a research hotspot. A number of clinical trials have shown that precision radiotherapy can significantly improve clinical prognosis of patients with hepatocellular carcinoma. In this article, the research progress and existing problems of radiotherapy in the treatment of hepatocellular carcinoma were reviewed, aiming to provide literature support for the application of radiotherapy in the treatment of hepatocellular carcinoma.

Value of flattening filter-free mode in deep inspiration breath-hold intensity-modulated radiotherapy after modified radical surgery for left breast cancer / 肿瘤研究与临床

Objective:To investigate the value of flattening filter-free (FFF) mode in postoperative deep inspiration breath-hold (DIBH) intensigy-modulated radiotherapy for left breast cancer.Methods:A retrospective case series study was conducted. Clinical data of 21 patients with left breast cancer who underwent DIBH intensity-modulated radiotherapy after modified radical surgery in Meizhou People's Hospital from January 2021 to December 2022 were retrospectively analyzed. On the DIBH-mode CT of each patient, the 7-field intensity-modulation plan was designed using the plan developed in the 6 MV FFF-mode (FFF group) or the plan developed in the 6 MV flattening filter (FF)-mode (FF group). The target areas and organs at risk, dosimetric and biological parameters, and dose validation results were compared between the two plans.Results:Twenty-one patients were female with the age [ M ( Q1, Q3)] of 47 years old (32 years old, 61 years old). The percentage of target areas receiving 95% of the prescribed dose (V 95%) was (95.9±0.8)% and (95.7±1.9)% in the FF and FFF groups ( t = 2.98, P = 0.089), and the maximum dose was (5 401±251) cGy and (5 424±201) cGy ( t = 2.85, P = 0.181), the fitness indices were 0.88±0.05 and 0.87±0.06 ( t = 0.32, P = 0.562), the homogeneity indices were 1.06±0.01 and 1.07±0.02 ( t = 2.91, P = 0.009), the equivalent uniform doses (EUD) were (51.81±0.21) Gy and (51.97±0.20) Gy ( t = 0.51, P = 0.309), and the tumor control probability (TCP) was (99.68±0.01)% and (99.61±0.02)% ( t = 0.81, P = 0.560). The plans of the FFF group and the FF group were compliant, and the doses of all organs at risk to be irradiated were within the clinically acceptable range, and the radiation doses in the FFF group in the left lung [5 Gy irradiated volume (V 5 Gy), mean dose (D mean), EUD and normal tissue complication rate (NTCP)], right lung (V 5 Gy and D mean), heart (V 10 Gy, D mean, EUD and NTCP), and right breast (V 5 Gy, D mean and EUD) were differently lower than those in the FF group, and the differences were statistically significant (all P < 0.05). The monitor units in the FFF and FF groups were (984±132) MU and (751±145) MU ( t = -1.25, P < 0.001), and the total beam-on time was (1.4±0.3) min and (2.2±0.4) min ( t = 0.68, P < 0.001); individual field beam-on time was (12±7) s and (16±10) s ( t = 2.68, P = 0.001), and the beam-on time for each field in patients of the FFF group was less than 25 s; γ pass rates were (97.1±2.8)% and (97.6±2.1)% ( t = 0.59, P = 0.484). Conclusions:In the intensity-modulated radiotherapy of left breast cancer, the radiation dose of the energy to the critical organs in FFF mode is lower and has higher dose rate and shorter treatment time. FFF combined with DIBH technique has positive clinical significance in the intensity-modulated radiotherapy of breast cancer.

Comparison of radiation dose calculation differences between uRT-TPS and Monaco-TPS for the same linear accelerator in multiple cancers / 中国癌症杂志

Background and purpose:In recent years,domestic radiotherapy equipment and related software have made great progress,and testing the functionality and stability of the equipment and software is an essential step.This paper focused on comparing the differences in intensity-modulated radiation therapy(IMRT)plans dosimetry and organ at risk(OAR)volume calculations for common cancers between uRT-treatment planning system(TPS)and Monaco-TPS,and to evaluate the feasibility of dose calculation for Infinity linac(linear accelerator,Elekta,Sweden)using uRT-TPS.Methods:Twenty cases of rectal cancer,lung cancer,breast cancer and nasopharyngeal carcinoma were selected.The IMRT plans were completed in uRT-TPS and Monaco-TPS.The dose uniformity and conformity,mean dose,maximum dose of planning target volume(PTV)and OAR between two plans under the same prescribed dose of PTV were compared.And the pass rates of two TPS plans validated at the same linear accelerator were compared.Meanwhile,monitor units(MU),source skin distance(SSD)and the volume of OAR in uRT-TPS and Monaco-TPS were compared.Results:Wonderful plans that met the clinical requirements were obtained in uRT-TPS and Monaco-TPS.Comparable uniformity and conformability was received in PTV,and the maximum dose of PTV was reduced by 1.1 Gy for uRT-TPS(P = 0.006).For breast cancer and lung cancer,the dose in lung was lower for Monaco-TPS(P＜0.05).For nasopharyngeal carcinoma,the dose indicators that oral cavity and throat in the uRT-TPS was reduced by 9.2%and 5.1%,respectively.The verification results of absolute point dose(＜3%)and three-dimensional surface dose(＞95%)for both plans met the clinical requirements.The region of interest in uRT-TPS was smaller compared with Monaco-TPS(P＜0.05).Conclusion:A comparable IMRT plan was obtained for common tumors in uRT-TPS and Monaco-TPS.It is feasible to calculate the dose of Infinity linac using uRT-TPS.

Clinical study of intensity-modulated radiation therapy combined with camrelizumab in the treatment of advanced hepatocellular carcinoma / 局解手术学杂志

Objective To investigate the efficacy and safety of intensity-modulated radiation therapy combined with camrelizumab in the treatment of advanced hepatocellular carcinoma(HCC).Methods A total of 84 patients with advanced HCC admitted to our hospital from January to December 2020 were selected as the study objects,and were randomly divided into the observation group and the control group,with 42 cases in each group.Patients in the observation group received intensity-modulated radiation therapy combined with carrelli-zumab,and patients in the control group received intensity-modulated radiation therapy.The short-term efficacy,immune function and long-term survival rate of patietns in the two groups were compared,and the incidence of adverse reactions was recorded.Results The total effec-tive rates of the observation group 1 month and 3 months after treatment were significantly higher than those of the control group(P<0.05).The levels of CD3+,CD4+ and CD4+/CD8+ 1 month and 3 months after treatment were all increased in the two groups,while the levels of CD8+ in both two groups were decreased(P<0.05),and the levels of CD3+,CD4+ and CD4+/CD8+ in the observation group were higher than those in the control group(P<0.05),and the levels of CD8+ in the observation group were lower than those in the control group(P<0.05).The median survival time of patients in the observation group was significantly longer than that of patients in the control group(P<0.05).The incidence of cutaneous capillary hyperplasia in the observation group was higher than that in the control group(P<0.001),and there was no significant difference in the incidence of other adverse reactions between the two groups(P>0.05),and all of adverse reactions were grades 1 to 2.Conclusion Intensity-modulated radiation therapy combined with camrelizumab has a good effect on HCC,it can improve the immune function of the body,and control the development of the disease,with good safety.

Quality re-optimization and assessment of radiotherapy plan for rectal cancer / 中国医学物理学杂志

Objective To evaluate the quality of treatment planning(TP)and re-optimization planning(RP)of radiotherapy for rectal cancer using PlanIQ software,thereby providing methods and tools for the screening and optimization of radiotherapy plans.Methods Twenty patients with rectal cancer who received radiotherapy were selected retrospectively,with 10 cases of intensity-modulated radiotherapy(IMRT)and 10 of volumetric modulated arc therapy(VMAT).(1)TP:IMRT plan involved 5-field irradiation,and VMAT plan involved two 360°arcs.The prescription doses were 50 Gy/25 f for PTV1 and 45 Gy/25 f for PTV2.All plans underwent direct machine parameter optimization and required 95%isodose lines to cover 100%of the target volume.Organs-at-risk(OAR)were limited by reference to tolerated dose standards.After the planning was completed,the plans were reviewed and confirmed by a physician,and the treatment was implemented after dose verification.(2)RP:a physicist with 10 years of experience re-optimized the 20 TP plans,with the irradiation technique and field setting unchanged.The re-optimization involved adjusting planning conditions and parameters based on individual experience until the dose to OAR was minimized while without affecting PTV coverage.The quality of TP plans and RP plans were quantitatively evaluated using PlanIQ software.Non-parametric Wilcoxon signed rank test was performed for dose-volume histogram parameters and plan quality index between two groups.Results The dose-volume histogram parameters in RP plans were superior to those in TP plans,and the differences in the Dmax of PTV1,the V45 Gy and Dmax of small intestine,and the V45 Gy of colon were statistically significant(P<0.05).The quality scores of RP plans for IMRT group,VMAT group and all patients were significantly higher than those of TP plans(P<0.05),with plan quality index of 88.55±3.35 vs 86.61±4.63(P=0.005),89.72±3.15 vs 87.21±3.04(P=0.028),and 89.14±3.22 vs 86.91±3.22(P=0.001),respectively.Conclusion RP can further improve the quality of radiotherapy plan for rectal cancer.PlanIQ software serves as an effective tool for quality control and screening of radiotherapy planning.

Effects of optimizing target volume on oral mucosal reaction and salivary gland function in oropharyngeal cancer patients undergoing intensity-modulated radiotherapy / 中国医学物理学杂志

Objective To analyze the effects of target volume optimization on oral mucosal reaction and salivary gland function in oropharyngeal cancer patients receiving intensity-modulated radiotherapy(IMRT).Methods A total of 120 patients with oropharyngeal cancer admitted to Affiliated Hospital of Jiangsu University from April 2020 to August 2022 were selected and randomly grouped into control group(n=60,conventional IMRT)and treatment group(n=60,cervical region Ⅱ and the oral target region were optimized during IMRT).The therapeutic efficacy,parotid gland dose,incidence of acute oral mucosal reaction,dry mouth and oral pain at 3 months after IMRT were compared between two groups.The resting-state apparent diffusion coefficient(ADC)values of parotid and submandibular glands at different time points(before radiotherapy,the 4th week of radiotherapy,the end of radiotherapy and 3 months after radiotherapy)were recorded.Results The difference in the objective reaction rate between two groups was trivial[80.00％(48/60)vs 75.00％(45/60),P>0.05].The mean dose(Dmean)and V34 of the unaffected parotid gland and the Dmean and V30 of the oral cavity in treatment group were lower than those in control group(P<0.05).The incidences of acute oral mucosal reaction,dry mouth and oral pain at 3 months after radiotherapy in treatment group were 41.67％,50.00％,and 58.33％,lower than those in control group(75.00％,78.33％,and 85.00％)(P<0.05).The resting-state ADC values of parotid and submandibular glands at the 4th week of radiotherapy,the end of radiotherapy,and 3 months after radiotherapy in both two groups were higher than those before radiotherapy(P<0.05).At the 4th week of radiotherapy,the end of radiotherapy,and 3 months after radiotherapy,the resting-state ADC values of parotid and submandibular glands in treatment group were lower than those in control group(P<0.05).Conclusion Optimizing target volume during oropharyngeal IMRT can effectively prevent the occurrence of radiation-induced mucositis,alleviate oral mucosal reaction,oral pain and dry mouth,reduce parotid gland dose,and diminish the effects of IMRT on salivary gland function in patients.

Comparison of interobserver variations in delineation of target volumes and organs-at-risk for intensity-modulated radiotherapy of nasopharyngeal carcinoma among physicians from different levels of cancer centers / 中国医学物理学杂志

Objective To assess inter-observer variations(IOV)in the delineation of target volumes and organs-at-risk(OAR)for intensity-modulated radiotherapy(IMRT)of nasopharyngeal carcinoma(NPC)among physicians from different levels of cancer centers,thereby providing a reference for quality control in multi-center clinical trials.Methods Twelve patients with NPC of different TMN stages were randomly selected.Three physicians from the same municipal cancer center manually delineated the target volume(GTVnx)and OAR for each patient.The manually modified and confirmed target volume(GTVnx)and OAR delineation structures by radiotherapy experts from the regional cancer center were used as the standard delineation.The absolute volume difference ratio(△V_diff),maximum/minimum volume ratio(MMR),coefficient of variation(CV),and Dice similarity coefficient(DSC)were used to compare the differences in organ delineation among physicians from different levels of cancer centers and among the 3 physicians from the same municipal cancer center.Furthermore,the IOV of GTVnx and OAR among physicians from different levels cancer centers were compared across different TMN stages.Results Significant differences in the delineation of GTVnx were observed among physicians from different levels of cancer centers.Among the 3 physicians,the maximum values of △V_diff,MMR,and CV were 97.23%±83.45%,2.19±0.75,and 0.31±0.14,respectively,with an average DSC of less than 0.7.Additionally,there were considerable differences in the delineation of small-volume OAR such as the left and right optic nerves,chiasm,and pituitary,with average MMR>2.8,CV>0.37,and DSC<0.51.However,relatively smaller differences were observed in the delineation of large-volume OAR such as the brainstem,spinal cord,left and right eyeballs,and left and right mandible,with average△V_diff<42%,MMR<1.55,and DSC>0.7.Compared with the differences among physicians from different levels cancer centers,the differences among the 3 physicians from the municipal cancer center were slightly reduced.Furthermore,there were also differences in the delineation of target volumes for NPC among physicians from different levels cancer centers,depending on the staging of the disease.Compared with the delineation of target volumes for earlier stage patients(stages I or II),the differences among physicians in the delineation of target volumes for advanced stage patients(stages III or IV)were smaller,with average △V_diff and DSC of 98.31%±67.36%vs 69.38%±72.61%(P<0.05)and 0.55±0.08 vs 0.72±0.12(P<0.05),respectively.Conclusion There are differences in the delineation of GTVnx and OAR in radiation therapy for NPC among physicians from different levels of cancer centers,especially in the delineation of target volume(GTVnx)and small-volume OAR for early-stage patients.To ensure the accuracy of multicenter clinical trials,it is recommended to provide unified training to physicians from different levels of cancer centers and review their delineation results to reduce the effect of differences on treatment outcomes.

Preliminary study on the distributions of dose differences and their correlations with tumor types in independent verification / 中国医学物理学杂志

Objective To explore the distributions of dose differences and their correlations with tumor types in independent three-dimensional dose verification for intensity-modulated radiotherapy(IMRT)plan,and to establish prediction models.Methods The fixed field IMRT plans of 180 patients with head and neck,chest,and abdominal tumors were collected.Independent sample t-test was used to analyze the consistency between the initial dose calculated in treatment planning system and the verified dose for evaluating the feasibility of independent validation.The distributions of planning target volume(PTV)dose differences among different tumor types were analyzed.The correlations of PTV dose differences with conformity index(CI)and homogeneity index were analyzed using correlation analysis and multiple linear regression method.Results The PTV dose differences for head and neck,chest,and abdominal tumors were within±1.2%,and the average 3%/3 mm gamma passing rate between the initial dose and the verified dose was higher than 99.5%,indicating good consistency in dose distribution between independent validation and treatment planning system.The distributions of PTV dose differences were different in head and neck,chest,and abdominal plans,and were significantly correlated with CI which could be used to preliminarily determine the PTV dose differences in independent validation.The multiple regression equation based on CI and homogeneity index could be used to estimate the dose verification differences of IMRT plan.Conclusion Independent verification can quickly achieve pre-treatment validation for radiotherapy plans,improving the efficiency of quality control of radiotherapy plans.The estimation based on dose differences provides guidance for optimizing radiotherapy plans.

Riesgo de osteorradionecrosis de los maxilares según el tipo de radioterapia / Risk of Osteoradionecrosis of the Jaws according to Type of Radiotherapy

Introducción: El cáncer de cabeza y cuello es el séptimo más común a nivel mundial. Las opciones terapéuticas para su manejo incluyen la radioterapia, la cual debe procurar un equilibrio entre la eliminación del tumor y la preservación del tejido sano porque su aplicación implica el riesgo de desarrollar una osteorradionecrosis de los maxilares. Objetivo: Valorar si el riesgo de que se produzca osteorradionecrosis de los maxilares varía en función del tipo de radioterapia. Métodos: Diseño documental, retrospectivo basado en los principios de las revisiones sistemáticas exploratorias según lo establece la lista de chequeo PRISMA Extension for Scoping Reviews (PRISMA-ScR). Se realizaron búsquedas en inglés y español en PubMed, LILACS, ScienceDirect, Tripdatabase y Epistemonikos. Resultados: En total se incluyeron 12 estudios publicados entre 2016 y 2022 con diversos diseños de investigación; el estudio de cohorte retrospectivo fue el que tuvo mayor representación. Se analizaron distintas opciones de radioterapia y sus protocolos, entre ellos, la radioterapia de intensidad modulada, la terapia de protones de intensidad modulada, la radioterapia corporal estereotáctica y la radioterapia tridimensional. La literatura refiere que los protocolos que implican dosis totales más bajas representan un menor riesgo de osteorradionecrosis. Conclusiones: El riesgo de osteorradionecrosis de los maxilares debe atribuirse, en mayor medida, a la dosis total de radiación recibida por el paciente y a la dosis por fracción que al tipo de radioterapia(AU)

Introduction: Head and neck cancer is the seventh most common cancer worldwide. Therapeutic options for its management include radiotherapy, which should seek a balance between tumor elimination and preservation of healthy tissue because its application implies the risk of developing osteoradionecrosis of the jaws. Objective: To assess whether the risk of developing osteoradionecrosis of the jaws varies according to the type of radiotherapy. Methods : Documentary, retrospective design based on the principles of exploratory systematic reviews as established by the PRISMA Extension for Scoping Reviews (PRISMA-ScR) checklist. PubMed, LILACS, ScienceDirect, Tripdatabase and Epistemonikos were searched in English and Spanish. Results: In total, 12 studies published between 2016 and 2022 with various research designs were included; the retrospective cohort study had the highest representation. Different radiotherapy options and their protocols were analyzed, including intensity-modulated radiotherapy, intensity-modulated proton therapy, stereotactic body radiotherapy, and three-dimensional radiotherapy. The literature refers that protocols involving lower total doses represent a lower risk of osteoradionecrosis. Conclusions: The risk of osteoradionecrosis of the jaws should be attributed, to a greater extent, to the total radiation dose received by the patient and the dose per fraction than to the type of radiotherapy(AU)

Dosimetric comparison of three?dimensional conformal radiation therapy, intensity?modulated radiation therapy, and volumetric?modulated arc therapy for free?breathing whole?breast irradiation: A planning study

Background: Currently, recommended heart dose constraints are difficult to meet in whole?breast irradiation (WBI) for left?sided breast cancer patients, who cannot be treated with the deep inspiration breath hold. We performed a radiotherapy planning study to establish if the use of intensity?modulated radiation therapy (IMRT) or volumetric?modulated arc therapy (VMAT) allows for better sparing of the heart and its subvolumes than the three?dimensional conformal radiation therapy (3D?CRT), and how these attempts affect the dose delivered to the other organs. Methods: A total of 17 left?sided and 10 right?sided consecutive patients treated with free?breathing WBI were retrospectively included. The 3D?CRT, IMRT, and VMAT plans were generated. Several dose杤olume parameters and plan quality indices were compared, separately for the left? and right?sided plans. Results: All the techniques fulfilled the planning objectives. In the left?sided plans, there was no heart or left ventricle dose reduction with IMRT, nor with VMAT; the maximum dose in the left anterior descending coronary artery was reduced with VMAT (P = 0.005); V5 for the contralateral breast, contralateral lung, and total?body increased markedly in VMAT, and for the ipsilateral lung (V5IL) also in IMRT, compared with 3D?CRT (P < 0.001). In the right?sided plans, the V5 values, except for V5IL, did not differ between the three techniques. Conclusions: IMRT and VMAT had a limited heart?sparing benefit in the left?sided free?breathing WBI, at the cost of increased low?dose volumes, measured by V5. The low?dose volumes are not increased by IMRT or VMAT in the right?sided WBI, where heart sparing is not a problem, but the attempts to reduce cardiac doses in the left?sided WBI increase them.

Dosimetric Impact of Titanium Alloy Implant in Spinal IMRT Plan / 中国医疗器械杂志

The purpose of this study is to establish and apply a correction method for titanium alloy implant in spinal IMRT plan, a corrected CT-density table was revised from normal CT-density table to include the density of titanium alloy implant. Dose distribution after and before correction were calculated and compared to evaluate the dose deviation. Plans were also copied to a spinal cancer simulation phantom. A titanium alloy fixation system for spine was implanted in this phantom. Plans were recalculated and compared with the measurement result. The result of this study shows that the max dose of spinal cord showed significant difference after correction, and the deviation between calculation results and measurement results was reduced after correction. The method for expanding the range CT-density table, which means that the density of titanium alloy was included, can reduce the error in calculation.

Effect of couch rotation angle on non-coplanar static intensity-modulated radiotherapy plan for gastric cancer / 中国辐射卫生

Objective To investigate the effect of couch rotation angle on non-coplanar static intensity-modulated radiotherapy (IMRT) plan for gastric cancer and to provide a reference for clinical planning. Methods A retrospective analysis was conducted on patients who recently underwent postoperative IMRT for gastric cancer. Twenty patients who received radiotherapy in the centre of Radiation Oncology of Huanggang Central Hospital from August 2022 to January 2023 were selected. That were selected to receive a seven-field coplanar static IMRT plan based on a couch rotation angle of 0° as the control group. Then, based on the coplanar IMRT plan, only the couch rotation angle of gantry angles 30° and 330° was changed to 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, respectively, and nine different non-coplanar plans were established. The homogeneity index (HI), conformity index (CI) of the target volume, and monitor unit (MU), as well as Dmean, V20, and V30 of the left and right kidneys, Dmax, Dmean, V10, V20, and V30 of the spinal cord, and Dmax, Dmean, V10, V20, V30, and V40 of the small intestine and liver were compared among the 10 plans. The MU and the dosimetric parameters of the target volumes and When the couch rotation angle was 60°, the minimum HI and maximum CI of the target volume were 0.0714±0.0089 and 0.9271±0.0108, respectively, and the minimum MU was 438±26, with the best homogeneity and conformity in the target volume and the shortest machine treatment time (P＜0.05). When the couch rotation angle was 10°, the Dmax of the small intestine was lowest, being (4620.73±99.27) cGy. When the couch rotation angle was 60°, the Dmean of the left and right kidneys was lowest, being (1246.30±130.35) cGy and (1001.52±103.33) cGy, respectively; the V20 of the left and right kidneys was lowest, being 22.87±6.29 and 19.69±1.84, respectively; the V10 and V30 of the spinal cord were lowest, being 40.08±4.92 and 1.68±0.34, respectively (P＜0.05). Conclusion The couch rotation angle has some influence on the postoperative treatment planning for patients with gastric cancer. In the design of non-coplanar plan for gastric cancer, the couch rotation angle of 60° contributes to establishing a better radiotherapy plan.

Analysis of dosimetric differences between active control and passive tracking of jaws / 中国辐射卫生

Objective To analyze the effect of the fixed-jaw technique on dosimetric parameters during dynamic intensity-modulated radiotherapy (DIMRT) planning. Methods Ten patients each with nasopharyngeal carcinoma, postoperative cervical cancer, and right breast cancer after radical surgery were selected for this study; all patients underwent DIMRT in our hospital in 2020. After administration at the prescribed dose, two methods were used to design the radiotherapy plan for each patient: split-field technique (SFT) and fixed-jaw technique (FJT). The two plans were compared for the differences in the dosimetric parameters and plan verification pass rate. Results Compared with SFT, FJT showed significant decreases (P <0.05) in the following parameters for patients with nasopharyngeal carcinoma, postoperative cervical cancer, and right breast cancer after radical surgery: number of radiation fields (down by 41.5%, 47.3%, and 34.9%, respectively, t = 7.954, 24.2, and 4.949, respectively), total number of monitor units (MUs) (down by 5.6%, 5.3%, and 13.5%, respectively, t = 3.211, 2.423, and 5.481, respectively), and actual beam-on time (down by 25.3%, 23.8%, and 13.6%, respectively, t = 5.814, 9.208, and 5.655, respectively). There were significant differences in some of the dosimetric parameters for all three types of cancer patients between the two plans (P <0.05). There were no significant differences in the plan verification pass rate (P >0.05). Conclusion FJT can reduce the total number of MUs and actual beam-on time while meeting the requirements for clinically prescribed doses in DIMRT planning.

Adaptive extended‑field intensity-modulated radiation therapy with simultaneously integrated boost for locally advanced cervical cancer with lymph node metastases / Philippine Journal of Obstetrics and Gynecology

@#Performing external beam radiotherapy alone without chemotherapy or brachytherapy for locally advanced cervical cancer with multiple lymph node metastases is challenging. The purpose of this case report is to present the efficacy of high‑dose adaptive extended‑field intensity‑modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) in treating locally advanced cervical cancer with multiple lymph node metastases. A 67‑year‑old woman with locally advanced squamous cell carcinoma of the uterine cervix was treated by external beam radiotherapy alone due to the refusal of chemotherapy and intracavitary brachytherapy. In order to maximize the efficacy of treatment, extended‑field radiotherapy that includes the paraaortic lymph nodes as well as an adaptive IMRT‑SIB plan, was applied. The treatment was successful, resulting in complete tumor disappearance without severe adverse events. In conclusion, high‑dose adaptive IMRT‑SIB may be an alternative treatment option for locally advanced cervical cancer with multiple lymph node metastases.

Analysis of risk factors of radiation-induced toxicity in limited-stage small cell lung cancer treated with hypofractionated intensity-modulated radiotherapy / 中华肿瘤杂志

Objective: To compare the incidence of radiation-related toxicities between conventional and hypofractionated intensity-modulated radiation therapy (IMRT) for limited-stage small cell lung cancer (SCLC), and to explore the risk factors of hypofractionated radiotherapy-induced toxicities. Methods: Data were retrospectively collected from consecutive limited-stage SCLC patients treated with definitive concurrent chemoradiotherapy in Cancer Hospital of Chinese Academy of Medical Sciences from March 2016 to April 2022. The enrolled patients were divided into two groups according to radiation fractionated regimens. Common Terminology Criteria for Adverse Events (CTCAE, version 5.0) was used to evaluate the grade of radiation esophagus injuries and lung injuries. Logistic regression analyses were used to identify factors associated with radiation-related toxicities in the hypofractionated radiotherapy group. Results: Among 211 enrolled patients, 108 cases underwent conventional IMRT and 103 patients received hypofractionated IMRT. The cumulative incidences of acute esophagitis grade ≥2 [38.9% (42/108) vs 35.0% (36/103), P=0.895] and grade ≥ 3 [1.9% (2/108) vs 5.8% (6/103), P=0.132] were similar between conventional and hypofractionated IMRT group. Late esophagus injuries grade ≥2 occurred in one patient in either group. No differences in the cumulative incidence of acute pneumonitis grade ≥2[12.0% (13/108) vs 5.8% (6/103), P=0.172] and late lung injuries grade ≥2[5.6% (6/108) vs 10.7% (11/103), P=0.277] were observed. There was no grade ≥3 lung injuries occurred in either group. Using multiple regression analysis, mean esophageal dose ≥13 Gy (OR=3.33, 95% CI: 1.23-9.01, P=0.018) and the overlapping volume between planning target volume (PTV) and esophageal ≥8 cm(3)(OR=3.99, 95% CI: 1.24-12.79, P=0.020) were identified as the independent risk factors associated with acute esophagitis grade ≥2 in the hypofractionated radiotherapy group. Acute pneumonitis grade ≥2 was correlated with presence of chronic obstructive pulmonary disease (COPD, P=0.025). Late lung injuries grade ≥2 was correlated with tumor location(P=0.036). Conclusions: Hypofractionated IMRT are tolerated with manageable toxicities for limited-stage SCLC patients treated with IMRT. Mean esophageal dose and the overlapping volume between PTV and esophageal are independently predictive factors of acute esophagitis grade ≥2, and COPD and tumor location are valuable factors of lung injuries for limited-stage SCLC patients receiving hyofractionated radiotherapy. Prospective studies are needed to confirm these results.

Feasibility assessment of Halcyon 3.0 dual-isocenter IMRT plan in postoperative radiotherapy of radical mastectomy for left side of breast cancer / 中国医学装备

Objective:To assess the feasibility of the designed dual-isocenter IMRT plans based on Halcyon 3.0 linear accelerator in postoperative radiotherapy of radical mastectomy for left side of breast cancer.Methods:A total of sixteen patients received the postoperative radiotherapy of radical mastectomy for left side of breast cancer at Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from December 2022 to June 2023 were retrospectively selected.The dual-isocenter plans based respectively on Halcyon 3.0 linear accelerator and Truebeam linear accelerator were designed,and the dosimetric parameters included conformity index(CI)values of target region,homogeneity index(HI)values and doses to organs at risk(OAR)of the two plans were calculated as statistic method.And then,the dosimetric performance of Halcyon 3.0 dual-isocenter plan was compared and analyzed.Utilizing two dose verification tools,ArcCHECK and Portal Dosimetry,to assess the precision of beam delivery of Halcyon 3.0 dual-isocenter plan.Results:The Halcyon dual-isocenter plan and the Truebeam single-isocenter plan had similar plan quality.There were not statistically significant differences(P>0.05)in dosimetric parameters such as CI,HI,exposure dose to 2%of the target volume(D2%)and exposure dose to 98%of the target volume(D98%).Compared to the average monitor unit(MU)of Truebeam single-isocenter plan,the MU values of Halcyon 3.0 dual-isocenter plan increased by 366 MU,while the difference was not statistically significant(P>0.05).The Halcyon 3.0 dual-isocenter plan provided comprehensive protection for OAR,which was better than that of the Truebeam single-isocenter plan.The values of the left side of lung volume(V20)that were covered by 20 Gy dose of the Halcyon 3.0 dual-isocenter plan and the Truebeam single-isocenter plan were respectively 20.41%±1.56%and 24.88%±2.95%,and the difference was statistically significant(t=6.413,P<0.05).There were not significant differences in other OAR dosimetric parameters between the two kinds of plans(P>0.05).The verification pass rates of the Halcyon 3.0 dual-isocenter plans on the ArcCHECK and Portal Dosimetry platforms were respectively 97.6%-98.9%and 98.1%-100%when the ratio of dose tolerance(DT)to distance to agreement(DTA)was set at 2%/2 mm.The verification pass rates of the Halcyon 3.0 dual-isocenter plans on the ArcCHECK and Portal Dosimetry platforms were respectively 99.1%-100%and 99.7%-100%when DT/DTA was set at 3%/3 mm.The beam delivery precision of the Halcyon 3.0 dual-isocenter plan could meet verification standards of clinical treatments.Conclusion:The Halcyon 3.0 dual-isocenter IMRT plan demonstrates a higher feasibility in the postoperative radiotherapy of radical mastectomy for left side of breast cancer.The precision of dose delivery of plan is high,and the dose of target area is sufficient,uniform and favorable conformability.It can effectively limit the OAR exposure dose at the same time.