Verification of Dosimetric and Positional Accuracy of Dynamic Tumor Tracking Intensity Modulated Radiation Therapy

Purpose: We performed both, dosimetric and positional accuracy verification of dynamic tumor tracking (DTT) intensity modulated radiation therapy (IMRT), with the Vero4DRT system using a moving phantom (QUASAR respiratory motion platform;QUASAR phantom) and system log files. Methods: The QUASAR phantom was placed on a treatment couch. Measurement of the point dose and dose distribution was performed for conventional IMRT, with the QUASAR phantom static and moving;for DTT IMRT, this was performed with the phantom moving for pyramid shaped, prostate, paranasal sinus, and pancreas targets. The QUASAR phantom was driven by a sinusoidal signal in the superior-inferior direction. Furthermore, predicted positional errors induced by the Vero4DRT system and mechanical positional errors of the gimbal head, were calculated using the system log files. Results and Conclusion: For DTT IMRT, the dose at the evaluation point was within 3% compared with the verification plan, and the dose distribution in the passing rates of γ was 97.9%, with the criteria of 3% dose and 3 mm distance to agreement. The position error calculated from the log files was within 2 mm, suggesting the feasibility of employing DTT IMRT with high accuracy using the Vero4DRT system.

Clinical study on concurrent and sequential therapy of intensity modulated radiation therapy (IMRT) combined with NP regimen chemotherapy in the treatment of middle and advanced non-small cell lung cancer

Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty patients with middle and advanced stage NSCLC were randomized into two groups. Forty patients were underwent sequential therapy and other 40 patients were underwent concurrent therapy. IMRT was used in radiotherapy and NP regimen of vinorelbine+cispatin (NP) was used in chemotherapy. Results: (1) The overall response (CR+PR) rate was 75% in concurrent group and 45% in sequential group (P<0.05); (2) The treatment courses were 84 days and 140 days for concurrent group and sequential group respectively (P<0.05); (3) One-year survival rate in concurrent group was 72.4% and 52.3% in sequential group respectively; (4) The toxic effects can be tolerable by all of patients. Conclusion: The concurrent chemo-radiotherapy has better overall re- sponse, one-year survival rate and shorter treatment course than the sequential chemo-radiotherapy, so it is a better method for the treatment of middle and advanced stage NSCLC, but the long term survival rate will be studied.

Unraveling the efficacy network: A network meta-analysis of adjuvant external beam radiation therapy methods after hepatectomy

BACKGROUND Primary liver cancer is a malignant tumor with a high recurrence rate that significantly affects patient prognosis.Postoperative adjuvant external radiation therapy(RT)has been shown to effectively prevent recurrence after liver cancer resection.However,there are multiple RT techniques available,and the differ-ential effects of these techniques in preventing postoperative liver cancer re-currence require further investigation.AIM To assess the advantages and disadvantages of various adjuvant external RT methods after liver resection based on overall survival(OS)and disease-free survival(DFS)and to determine the optimal strategy.METHODS This study involved network meta-analyses and followed the PRISMA guidelines.The data of qualified studies published before July 10,2023,were collected from PubMed,Embase,the Web of Science,and the Cochrane Library.We included relevant studies on postoperative external beam RT after liver resection that had OS and DFS as the primary endpoints.The magnitudes of the effects were determined using risk ratios with 95%confidential intervals.The results were analyzed using R software and STATA software.RESULTS A total of 12 studies,including 1265 patients with hepatocellular carcinoma(HCC)after liver resection,were included in this study.There was no significant heterogeneity in the direct paired comparisons,and there were no significant differences in the inclusion or exclusion criteria,intervention measures,or outcome indicators,meeting the assumptions of heterogeneity and transitivity.OS analysis revealed that patients who underwent stereotactic body radiotherapy(SBRT)after resection had longer OS than those who underwent intensity modulated radiotherapy(IMRT)or 3-dimensional conformal RT(3D-CRT).DFS analysis revealed that patients who underwent 3D-CRT after resection had the longest DFS.Patients who underwent IMRT after resection had longer OS than those who underwent 3D-CRT and longer DFS than those who underwent SBRT.CONCLUSION HCC patients who undergo liver cancer resection must consider distinct advantages and disadvantages when choosing between SBRT and 3D-CRT.IMRT,a RT technique that is associated with longer OS than 3D-CRT and longer DFS than SBRT,may be a preferred option.

Treatment outcomes for different subgroups of nasopharyngeal carcinoma patients treated with intensity-modulated radiation therapy

Although many studies have investigated intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC),sample sizes in the reported studies are usually small and different in outcomes in different T and N subgroups are seldom analyzed.Herein,we evaluated the outcomes of NPC patients treated with IMRT and further explored treatment strategy to improve such outcome.We collected clinical data of 865 NPC patients treated with IMRT alone or in combination with chemotherapy,and classified all cases into the following prognostic categories according to different TNM stages:early stage group (T1-2N0-1M0),advanced local disease group (T3-4N0-1M0),advanced nodal disease group (T1-2N2-3M0),and advanced locoregional disease group (T3-4N2-3M0).The 5-year overall survival (OS),local relapse-free survival (LRFS),and distant metastases-free survival (DMFS) were 83.0%,90.4%,and 84.0%,respectively.The early disease group had the lowest treatment failure rate,with a 5-year OS of 95.6%.The advanced local disease group and advanced nodal disease group had similar failure pattern and treatment outcomes as well as similar hazard ratios for death (4.230 and 4.625,respectively).The advanced locoregional disease group had the highest incidence of relapse and death,with a 5-year DMFS and OS of 62.3% and 62.2%,respectively,and a hazard ratio for death of 10.402.Comparing with IMRT alone,IMRT in combination with chemotherapy provided no significant benefit to locoregionally advanced NPC.Our results suggest that the decision of treatment strategy for NPC patients should consider combinations of T and N stages,and that IMRT alone for early stage NPC patients can produce satisfactory results.However,for advanced local,nodal,and locoregional disease groups,a combination of chemotherapy and radiotherapy is recommended.

Intensity modulated radiation therapy with simultaneous integrated boost based dose escalation on neoadjuvant chemoradiation therapy for locally advanced distal esophageal adenocarcinoma

AIM:To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost(IMRT-SIB).METHODS:We retrospectively reviewed the patients who underwent four-dimensional-based IMRT-SIBbased neoadjuvant chemoradiation protocol.During the concurrent chemoradiation therapy,radiation therapy was through IMRT-SIB delivered in 28 consecutive daily fractions with total radiation doses of 56 Gy to tumor and 5040 Gy dose-painted to clinical tumor volume,with a regimen at the discretion of the treating medical oncologist.This was followed by surgical tumor resection.We analyzed pathological completion response(p CR) rates its relationship with overall survival and event-freesurvival.RESULTS:Seventeen patients underwent dose escalation with the IMRT-SIB protocol between 2007 and 2014 and their records were available for analysis.Among the IMRT-SIB-treated patients,the toxicity appeared mild,the most common side effects were grade 1-3 esophagitis(46%) and pneumonitis(11.7%).There were no cardiac events.The Ro resection rate was 94%(n = 16),the p CR rate was 47%(n = 8),and the postoperative morbidity was zero.There was one mediastinal failure found,one patient had local failure at the anastomosis site,and the majority of failures were distant in the lung or bone.The 3-year diseasefree survival and overall survival rates were 41%(n = 7) and 53%(n = 9),respectively.CONCLUSION:The dose escalation through IMRT-SIB in the chemoradiation regimen seems responsible for down-staging the distal esophageal with well-tolerated complications.

Leakage-Penumbra effect in intensity modulated radiation therapy step-and-shoot dose delivery

AIM: To study the leakage-penumbra(LP) effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS: Leakage-penumbra dose profiles from 10 randomly selected prostate IMRT plans were studied. The IMRT plans were delivered by a Varian 21 EX linear accelerator equipped with a 120-leaf multileaf collimator(MLC). For each treatment plan created by the Pinnacle3 treatment planning system,a 3-dimensional LP dose distribution generated by 5 coplanar photon beams,starting from 0o with equal separation of 72 o,was investigated. For each photon beam used in the stepand-shoot IMRT plans,the first beam segment was set to have the largest area in the MLC leaf-sequencing,and was equal to the planning target volume(PTV). The overshoot effect(OSE) and the segment positional errors were measured using a solid water phantom with Kodak(TL and X-OMAT V) radiographic films. Film dosimetric analysis and calibration were carried out using a film scanner(Vidar VXR-16). The LP dose profiles were determined by eliminating the OSE and segment positional errors with specific individual irradiations. RESULTS: A non-uniformly distributed leaf LP dose ranging from 3% to 5% of the beam dose was measured in clinical IMRT beams. An overdose at the gap between neighboring segments,represented as dose peaks of up to 10% of the total BP,was measured. The LP effect increased the dose to the PTV and surrounding critical tissues. In addition,the effectdepends on the number of beams and segments for each beam. Segment positional error was less than the maximum tolerance of 1 mm under a dose rate of 600 monitor units per minute in the treatment plans. The OSE varying with the dose rate was observed in all photon beams,and the effect increased from 1 to 1.3 Gy per treatment of the rectal intersection. As the dosimetric impacts from the LP effect and OSE may increase the rectal post-radiation effects,a correction of LP was proposed and demonstrated for the central beam profile for one of the planned beams. CONCLUSION: We concluded that the measured dosimetric impact of the LP dose inaccuracy from photon beam segment in step-and-shoot IMRT can be corrected.

Dosimetric Improvements Utilising Intensity Modulated Radiation Therapy for Patients with Glioblastoma Multiforme

Aims: The EORTC-NCI study investigating the addition of temozolomide trial to standard radiation therapy has demonstrated improved duration of survival in patients with Glioblastoma multiforme (GBM). With longer survival duration, there is the potential for latent RT morbidity, not previously seen in historical patients. This study evaluates the potential dosimetric advantages of utilising IMRT over 3D-conformal RT in such patients. Methods: 10 consecutive patients with GBM formally screened for a clinical study over a two-month period were planned and treated with IMRT utilising daily on-board imaging (OBI). The EORTC protocol dosimetric criteria and constraints were used in target delineation and planning. For each patient, a 3DCRT plan was also produced. Endpoints for dosimetric evaluation analysed related to tumour dose: mean PTV60 dose (mPTV60Dose), Conformity Index (CI);and normal tissue dose: mean normal brain dose (mBrainDose) and V40 Brain (Brainv40). IGRT endpoints were the median isocentre shifts required in 3 axes measured in one direction. The variation between the IMRT and 3DCRT dosimetric endpoints was examined using Wilcoxon analysis. Results: The 10 patients had tumours located in temporal (3), parietal (3), occipital (2) and callosal (2) regions. The median PTV and normal brain volumes were 308.1 cm3 and 1077.5 cm3 respectively. The IMRT dosimetry was significantly improved in all endpoints specifically CI (p = 0.002), mPTV60Dose (p = 0.004), mBrainDose (p = 0.002) and Brainv40 (p = 0.019). OBI directed isocentre measurements in the patient group were available for 230 treatments. The median shifts (and 95% C.I.s) were 0.1 cm vertical (0.1 - 0.2), 0.1 cm longitudinal (0.1 - 0.2) and 0.2 cm lateral (0.2 - 0.2). At a minimum follow-up of 2 years’ post diagnosis, the median survival of the group is 18.0 months (95% CI: 13.4 - 22.6 months). Conclusion: IMRT for GBM produces significant dosimetric advantages in relation to planning target volume and normal tissue dose compared with 3D conformal plans. The data also confirm the accuracy of IMRT technique for CNS with IGRT delivery utilising OBI demonstrating minimal deviation from planned to treated isocentre.

A prospective trial of volumetric intensity-modulated arc therapy vs conventional intensity modulated radiation therapy in advanced head and neck cancer

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.

Comparison of efficacy and safety between late-course and simultaneous integrated dose-increasing intensity-modulated radiation therapy for cervical cancer complicated with pelvic lymph node metastasis

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.

Effect of intensity modulated radiation therapy combined with paclitaxel+ endostar chemotherapy on serum malignant molecule levels in patients with locally advanced non-small cell lung cancer

Objective: To discuss the effect of intensity modulated radiation therapy combined with paclitaxel + endostar chemotherapy on serum malignant molecule levels in patients with locally advanced non-small cell lung cancer. Methods: Patients with locally advanced NSCLC who were treated in the hospital between February 2015 and January 2017 were collected and divided into control group (n=59) and research group (n=59) by random number table. Control group received the routine paclitaxel + endostar chemotherapy after the operation, and research group underwent intensity modulated radiation therapy combined with paclitaxel +endostar chemotherapy after the operation. The differences in serum levels of NSCLC-related tumor markers and angiogenesis indexes were compared between the two groups before and after treatment. Results: Before treatment, the differences in serum levels of NSCLC-related tumor markers and angiogenesis indexes were not statistically significant between the two groups. After treatment, serum TK1, CYFRA21-1, Pro-GRP, CEA, CA125 and SCC-Ag levels of research group were lower than those of control group;serum EGFR, COX-2, VEGF, HIF-1 and MMP-2 levels of research group were lower than those of control group. Conclusion:Postoperative intensity modulated radiation therapy combined with paclitaxel + endostar chemotherapy can effectively reduce the serum malignant molecule levels and optimize the illness in patients with local advanced NSCLC.

Bilateral diffuse grade 5 radiation pneumonitis after intensity modulated radiation therapy for localized lung cancer

We are reporting a case of fatal radiation pneumonitis that developed six months following chemoradiation for limited stage small cell lung cancer.The patient was a 67-year-old man with a past medical history of Hashimoto's thyroiditis and remote suspicion for CREST,neither of which were active in the years leading up to treatment.He received 6600 cG y delivered in 200 cG y daily fractions via intensity modulated radiation therapy with concurrent cisplatin/etoposide followed by additional chemotherapy with dosereduced cisplatin/etoposide and carboplatin/etoposide and then received prophylactic cranial irradiation.The subsequent months were notable for progressively worsening episodes of respiratory compromise despite administration of prolonged steroids and he ultimately expired.Imaging demonstrated bilateral interstitial and airspace opacities.Autopsy findings were consistent with pneumonitis secondary to chemoradiation as well as lymphangitic spread of small cell carcinoma.The process was diffuse bilaterally although his radiation was delivered focally to the right lung and mediastinum.

Prostate specific antigen bounce after intensity-modulated radiation therapy in an Asian population

Objective:Serum prostate specific antigen(PSA)is commonly used to evaluate treatment response after definitive radiation therapy(RT).However,PSA levels can temporarily rise without a clear reason,termed“PSA bounce”,and often engender great anxiety for both patients and physicians.The present study aimed to determine the prevalence and factors that predict“PSA bounce”after intensity-modulated radiation therapy(IMRT),and the relevance to biochemical failure and cancer recurrence in an Asian population.Methods:We retrospectively reviewed 206 patients who received IMRT for prostate cancer from 2004 to 2012 in the National Cancer Centre Singapore.These patients were followed up with regular PSA monitoring.We defined“PSA bounce”as a rise of 0.1 ng/mL,followed by two consecutive falls.Patients with biochemical failure(PSA nadir t 2 ng/mL)were further evaluated for cancer recurrence.Results:Sixty-one patients(29.6%)experienced“PSA bounce”,at a median time of 16 months and lasted for 12 months.Age remained the most consistent predictor of the incidence,duration and extent of“PSA bounce”.Other contributory factors included baseline PSA,Gleason score and PSA nadir.Hormonal therapy and prostate volume did not affect this phenomenon.Sixteen patients(7.8%)developed biochemical recurrence,at median time of 32 months,of which 11 were confirmed to have metastatic disease.The median follow-up time was 71 months.

Local definitive intensity-modulated radiation therapy recommended for patients initially diagnosed with nasopharyngeal carcinoma with distant metastasis after an effective systemic chemotherapy

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.

Effects of intensity modulated radiation therapy + local hyperthermia on the cancer cell apoptosis and invasion in liver cancer lesion

Objective: To investigate the effects of intensity modulated radiation therapy + local hyperthermia on the cancer cell apoptosis and invasion in liver cancer lesion. Methods:A total of 94 patients with middle-advanced primary liver cancer who were diagnosed and treated in this hospital between November 2015 and February 2017 were divided into control group (n=47) and experimental group (n=47) by random number table method. Control group received intensity modulated radiation therapy and experimental group received intensity modulated radiation therapy + local hyperthermia. Both groups accepted peritoneal lesion biopsy before and after treatment, and the expression of apoptosis and invasion genes in specimen tissue were detected by fluorescence quantitative PCR. Results: There was no statistically significant difference in apoptosis and invasion gene expression between the two groups of patients before treatment. After treatment, apoptosis genes Fas, caspase-3, Bax and p53 mRNA expression in lesion tissue of experimental group were higher than those of control group whereas FasL and Bcl-2 mRNA expression were lower than those of control group;invasion genes Cofilin-1, Bmi-1, STAT3 and SOX18 mRNA expression in lesion tissue of experimental group were lower than those of control group whereas Tip30 and TP53IP1 mRNA expression were higher than those of control group. Conclusion: intensity modulated radiation therapy + local hyperthermia can effectively promote cancer cell apoptosis and inhibit its invasion activity in patients with middle and advanced primary liver cancer.

The Impact of Variation in Bladder Volume on the Doses of Target and Organ-at-Risk in Intensity-Modulated Radiation Therapy for Localized Prostate Cancer

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 [cm3] predicted deviations in the bladder V70Gy, V50Gy, and V30Gy [%];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.

Long-term outcomes of a phase Ⅱ randomized controlled trial comparing intensity-modulated radiotherapy with or without weekly cisplatin for the treatment of locally recurrent nasopharyngeal carcinoma

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.

宫颈癌卵巢移位术后IMRT与VMAT放疗对卵巢功能保护的剂量学评估

目的评估宫颈癌患者在接受卵巢移位术后,固定野调强放疗(IMRT)与容积旋转调强放疗(VMAT)在保护卵巢功能方面的剂量学优势。方法选取2016年1月—2022年1月淮安市第二人民医院收治的44例宫颈鳞癌卵巢移位术后需行辅助放疗的患者。根据放疗方式不同分为IMRT组和VMAT组,每组22例。IMRT组采用9野均分共面照射,VMAT组采用双全弧共面照射。比较2种放疗方式的剂量学差异及对卵巢功能的影响,分析移位卵巢位置与卵巢剂量之间的关系。结果IMRT在保留双侧卵巢时计划靶体积(PTV)的D2%、D98%、CI、HI各项参数均优于VMAT计划。在保护卵巢方面,IMRT卵巢Dmean(5.01±1.14)Gy、Dmax(8.08±2.65)、V5(50.63±30.23)、V7(16.11±22.68)均低于VMAT计划(P<0.05)。对危及器官的保护,IMRT组患者治疗前后雌二醇的差值高于VMAT组患者(P<0.05),LH和FSH的差值均低于VMAT组患者(P<0.05);两组治疗前后左右股骨头Dmean和直肠D2%的差值比较,差异均无统计学意义(P>0.05)。单因素分析发现,IMRT治疗组与VMAT治疗组卵巢中心层面距同侧PTV的横向距离与卵巢平均剂量比较,差异均有统计学意义(P<0.05),IMRT治疗组卵巢平均剂量与卵巢中心层面距髂嵴平面纵向距离呈正相关(r=0.667,P<0.05),与卵巢中心层面距PTV最近距离、卵巢中心层面距同侧PTV横向距离均呈负相关(r=-0.824和-0.907,均P<0.05),同时与卵巢体积呈负相关(r=-0.370,P<0.05)。VMAT治疗组卵巢平均剂量与卵巢中心层面距髂嵴平面纵向距离呈正相关(r=0.624,P<0.05),与卵巢中心层面距PTV最近距离、卵巢中心层面距同侧PTV横向距离均呈负相关(r=-0.804和-0.885,均P<0.05),同时与卵巢体积呈负相关(r=-0.340,P<0.05)。结论通过剂量学比较,IMRT放疗在宫颈癌卵巢移位术后保护卵巢功能方面更具优势。通过测量卵巢中心层面距同侧PTV的横向距离可以预测卵巢剂量。

The impact of intensity modulated radiotherapy on the skin dose for deep seated tumors

Objective: The purpose of this study was to investigate the impact of intensity modulated radiotherapy (IMRT) on surface doses for brain, abdomen and pelvis deep located tumors treated with 6 MV photon and to evaluate the skin dose calculation accuracy of the XIO 4.04 treatment planning system. Methods: More investigations for the influences of IMRT on skin doses would increase its applications for many treatment sites. Measuring skin doses in real treatment situations would reduce the uncertainty of skin dose prediction. In this work a pediatric human phantom was covered by a layer of 1 mm bolus at three treatment sites and thermoluminescent dosimeter (TLD) chips were inserted into the bolus at each treatment site before CT scan. Two different treatment plans [three-dimensional conformal radiation therapy (3DCRT) and IMRT] for each treatment sites were performed on XIO 4.04 treatment planning system using superposition algorism. Results: The results showed that the surface doses for 3DCRT were higher than the surface doses in IMRT by 1.6%, 2.5% and 3.2% for brain, abdomen and pelvis sites respectively. There was good agreement between measured and calculated surface doses, where the calculated surface dose was 15.5% for brain tumor calculated with 3DCRT whereas the measured surface dose was 12.1%. For abdomen site the calculated surface dose for IMRT treatment plan was 16.5% whereas the measured surface dose was 12.6%. Conclusion: The skin dose in IMRT for deep seated tumors is lower than that in 3DCRT which is another advantage for the IMRT. The TLD readings showed that the difference between the calculated and measured point dose is negligible. The superposition calculation algorism of the XIO 4.04 treatment planning system modeled the superficial dose well.

BMS-IMRT与三维适形放疗在宫颈癌术后放疗中的剂量学优势及对危及器官的影响

目的 比较骨髓单独限量调强适形放疗(BM S-IM RT)与三维适形放疗(3D-CRT)在宫颈癌术后全盆腔放疗中的剂量学差异,并探讨对危及器官(OARs)的影响。方法 回顾性分析2018年8月至2020年8月本院收治的40例宫颈癌术后行全盆腔放疗患者的临床病例资料,根据术后放疗方式不同分为BMS-I MRT组(n=16)与3D-CRT组(n=24),BMS-IMRT组接受BMS-IMRT计划,3D-CRT组接受3D-CRT计划。比较2组靶区剂量分布,OARs的剂量学差异以及骨髓抑制情况。结果 BMS-IMRT组和3D-CRT组的D_(95)[(44.78±0.42) vs (44.61±0.57)]、V_(95)[(99.40±2.73) Vs(99.07±5.26)]比较,均无统计学差异(P>0.05);BMS-IMRT组的均匀指数(HI)[(1.07±0.04) vs (1.11±0.02)]/适形指数(CI)[(0.67±0.10) vs (048±0.07)]均优于3D-CRT组,差异有统计学意义(P<0.06);3D-CRT组直肠、膀胱、小肠的V_(40),小肠V_(35),骨髓V_(20)和骨髓V_(10)均明显高于BMS-IMRT组(P<0.05);BMS-IMRT组Ⅱ级及以上骨髓抑制的比例明显低于3D-CRT组[66.67%vs 31.25%](P<0.05)。结论 宫颈癌术后全盆腔放疗中,BMS-IMRT计划在保证靶区剂量前提下,更有助于保护危及器官,改善骨髓抑制情况。

Intensity-modulated Radiotherapy for Sinonasal Teratocarcinosarcoma

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.