CalcNTCP: A simple tool for computation of normal tissue complication probability (NTCP) associated with cancer radiotherapy

Purpose: This study was aimed to develop a simple and user-friendly software for fast and accurate computation of normal tissue complication probability (NTCP) in accordance with the Lyman model.

Materials and methods: The software CalcNTCP has been developed in Visual Basic and is equipped with two functional modes. Mode 1 is based on pre-stored values of various parameters for 27 different organ systems and the user has only to input the values of volume fraction (v) and radiation dose (D), whereas Mode 2 is designed for the customized entries.

Results: The results of software validation have demonstrated that CalcNTCP is more efficient and time-saving as compared to manual or semi-manual procedures. The shapes and locations of representative survival curves generated by CalcNTCP-based computations for various radiation doses (10 – 100 Gy) and reference volumes (0.33 – 1.00) absolutely matched with optimal curves.

Conclusion: CalcNTCP is a simple, fast and accurate tool for the computation of NTCP with a direct implication in the evaluation or optimization of radiotherapy treatment plans.     

Treatment of pancreatic cancer tumors with intensity-modulated radiation therapy (IMRT) using the volume at risk approach (VARA): employing dose-volume histogram (DVH) and normal tissue complication probability (NTCP) to evaluate small bowel toxicity.

The emergent use of a combined modality approach (chemotherapy and radiation) in pancreatic cancer is associated with increased gastrointestinal toxicity. Intensity-modulated radiation therapy (IMRT) has the potential to deliver adequate dose to the tumor volume while decreasing the dose to critical structures such as the small bowel. We evaluated the influence of IMRT with inverse treatment planning on the dose-volume histograms (DVHs) of normal tissue compared to standard 3-dimensional conformal radiation treatment (3D-CRT) in patients with pancreatic cancer. Between July 1999 and May 2001, 10 randomly selected patients with adenocarcinoma of the pancreatic head were planned simultaneously with 3D-CRT and inverse-planned IMRT using the volume at risk approach (VaRA) and compared for various dosimetric parameters. DVH and normal tissue complication probability (NTCP) were calculated using IMRT and 3D-CRT plans. The aim of the treatment plan was to deliver 61.2 Gy to the gross tumor volume (GTV) and 45 Gy to the clinical treatment volume (CTV) while maintaining critical normal tissues to below specified tolerances. IMRT plans were more conformal than 3D-CRT plans. The average dose delivered to one third of the small bowel was lower with the IMRT plan compared to 3D-CRT. The IMRT plan resulted in one third of the small bowel receiving 30.2+/-12.9 Gy vs. 38.5+/-14.2 Gy with 3D-CRT (p = 0.006). The median volume of small bowel that received greater than either 50 or 60 Gy was reduced with IMRT. The median volume of small bowel exceeding 50 Gy was 19.2+/-11.2% (range 3% to 45%) compared to 31.4+/-21.3 (range 7% to 70%) for 3D-CRT (p = 0.048). The median volume of small bowel that received greater than 60 Gy was 12.5+/-4.8% for IMRT compared to 19.8+/-18.6% for 3D-CRT (p = 0.034). The VaRA approach employing IMRT techniques resulted in a lower dose per volume of small bowel that exceeded 60 Gy. We used the Lyman-Kutcher models to compare the probability of small bowel injury employing IMRT compared to 3D-CRT. The BIOPLAN model predicted a small bowel complication probability of 9.3+/-6% with IMRT compared to 24.4+/-18.9% with 3D-CRT delivery of dose (p = 0.021). IMRT with an inverse treatment plan has the potential to significantly improve radiation therapy of pancreatic cancers by reducing normal tissue dose, and simultaneously allow escalation of dose to further enhance locoregional control.     

Assessment and quantification of patient set-up errors in nasopharyngeal cancer patients and their biological and dosimetric impact in terms of generalized equivalent uniform dose (gEUD), tumour control probability (TCP) and normal tissue complication probability (NTCP)

Objective:

The aim of this study is to assess and quantify patients'' set-up errors using an electronic portal imaging device and to evaluate their dosimetric and biological impact in terms of generalized equivalent uniform dose (gEUD) on predictive models, such as the tumour control probability (TCP) and the normal tissue complication probability (NTCP).

Methods:

20 patients treated for nasopharyngeal cancer were enrolled in the radiotherapy–oncology department of HCA. Systematic and random errors were quantified. The dosimetric and biological impact of these set-up errors on the target volume and the organ at risk (OARs) coverage were assessed using calculation of dose–volume histogram, gEUD, TCP and NTCP. For this purpose, an in-house software was developed and used.

Results:

The standard deviations (1SDs) of the systematic set-up and random set-up errors were calculated for the lateral and subclavicular fields and gave the following results: ∑ = 0.63 ± (0.42) mm and σ = 3.75 ± (0.79) mm, respectively. Thus a planning organ at risk volume (PRV) margin of 3 mm was defined around the OARs, and a 5-mm margin used around the clinical target volume. The gEUD, TCP and NTCP calculations obtained with and without set-up errors have shown increased values for tumour, where ΔgEUD (tumour) = 1.94% Gy (p = 0.00721) and ΔTCP = 2.03%. The toxicity of OARs was quantified using gEUD and NTCP. The values of ΔgEUD (OARs) vary from 0.78% to 5.95% in the case of the brainstem and the optic chiasm, respectively. The corresponding ΔNTCP varies from 0.15% to 0.53%, respectively.

Conclusion:

The quantification of set-up errors has a dosimetric and biological impact on the tumour and on the OARs. The developed in-house software using the concept of gEUD, TCP and NTCP biological models has been successfully used in this study. It can be used also to optimize the treatment plan established for our patients.

Advances in knowledge:

The gEUD, TCP and NTCP may be more suitable tools to assess the treatment plans before treating the patients.The main goal of radiation therapy planning is to maximize dose to the target while minimizing dose to the nearby healthy organs, in order to improve the control of tumour growth and to reduce side effects. Nasopharyngeal cancer is common in North Africa, especially in Algeria. It is the highest cause of death among head and neck cancer patients according to “Registre du cancer”.¹ Recently, a three-dimensional conformal radiotherapy (3D-CRT) technique has been implemented in the radiotherapy–oncology department of the Mohamed Seghir Nekkache hospital (HCA) in Algiers.In order to evaluate and to achieve the most optimized treatment plans, predictive models that describe the relationship between dose distributions in organs at risk (OARs) and the probability of radiation-induced complications are needed,² especially those resulting from patient set-up errors. Of course, it is an increasingly important part of the clinical radiotherapy process, for which set-up errors consist of both a systematic component and a random component. The former happens when we have the same deviation in the same direction for each fraction throughout the whole course of treatment, while random errors vary from day-to-day.³ One way to diminish systematic as well as random set-up deviations is to use electronic portal imaging devices (EPIDs). Effectively, the EPIDs have become available in a large number of institutions for the sake of determining the set-up errors over previous years.^4–6In our study, both types of systematic and random errors were investigated for 20 nasopharynx radiotherapy patients by applying EPIDs. Patient set-up error evaluation in head and neck cancers constitute a challenge partly because the planning target volume (PTV) and the planning organ-at-risk volume (PRV) margins must be specified.⁷Unfortunately, when set-up errors occur and a PTV is surrounding the OARs, the dose distributions are not always uniform. In this case, tools are needed to evaluate treatment plans in 3D-CRT.⁸ One way this can be used consists of converting dose–volume histograms (DVHs) to an equivalent uniform dose (EUD),⁹ and then estimating the tumour control probability (TCP) and the normal tissue complication probability (NTCP).^10,11The concept of EUD, introduced by Niemierko,¹² was originally defined as the absorbed dose, that is, if given uniformly, would lead to the same cell death as the actual non-uniform absorbed-dose distribution. The current definition of EUD is the generalized mean absorbed dose. According to Niemierko who generalized its application to normal structures and tumours, the concept of EUD has been used as one of the several metrics to determine the impact of absorbed-dose heterogeneity on normal tissues and tumours. EUD is also well suited for obtaining the biological effect for the heterogeneous irradiation of a volume of interest,¹³ whereas TCP and NTCP are predictive models that will be affected by set-up errors and organ motion.¹⁴     

Multivariate normal tissue complication probability modeling of vaginal late toxicity after brachytherapy for cervical cancer

PurposeTo explore the best variables combination for a predictive model of vaginal toxicity in cervical cancer patients undergoing brachytherapy (BT).Methods and MaterialsClinical and 3-dimensional dosimetric parameters were retrospectively extracted from an institutional database of consecutive patients undergoing intracavitary BT after external beam radiation therapy from 2006 to 2013 for a cervical cancer. A least absolute shrinkage and selection operator selection procedure in Cox's proportional hazards regression model was performed to select a set of relevant predictors for a multivariate normal tissue complication probability model of Grade ≥2 vaginal late toxicity. Outcomes reliability was internally assessed by bootstrap resampling method.ResultsOne hundred sixty-nine women were included in the present study with a median followup time of 3.8 years (interquartile range [IQR], 1.9–5.6 years). The 2 years and 5 years cumulative incidence rates of Grade ≥2 late vaginal toxicity were 19.9% and 27.5%, respectively. Among 31 metrics and six clinical factors extracted, the optimal model included two dosimetric variables: V70_Gy and D5_% (the percentage volume that received a dose greater or equal to 70 Gy and the minimum dose given to the hottest 5% volume, respectively). Area under the ROC curve at 2 and 5 years of followup were 0.85 and 0.91, respectively. Regarding internal validation, median area under the ROC curve of bootstrap predictions was 0.83 (IQR, 0.78–0.88) and 0.89 (IQR, 0.85–0.93) at 2 and 5 years of followup, respectively.ConclusionsA multivariate normal tissue complication probability model for severe vaginal toxicity based on two dosimetric variables (V70_Gy and D5_%) provides reliable discrimination capability in a cohort of cervical cancer treated with external beam radiation therapy and BT.     

肺癌放疗后放射性肺损伤CT分级与正常组织并发症概率的关系

目的 探讨非小细胞肺癌 (NSCLC)三维适形放疗(3DCRT)后放射性肺损伤的CT分级与正常组织并发症概率(NTCP)的关系。方法 将3DCRT治疗后CT随访6个月以上的169例Ⅰ～Ⅲ期NSCLC患者按随访CT放射性肺损伤的表现分级并分为CT阳性组(2～4级)和CT阴性组(0、1级),复习全部病例的治疗计划,按全肺NTCP和患侧肺的NTCP分布各分为5组,对比分析放射性肺损伤CT分级与NTCP的关系。结果 不同CT分级的全肺和患侧肺NTCP值差异有统计学意义(全肺P=0.004,患侧肺P=0.000);全肺NTCP分组和患侧肺NTCP分组研究均显示患侧肺CT分级阳性率组间差异有统计学意义(全肺P=0.003,患侧肺P=0.000)。结论 NSCLC行3DCRT后放射性肺损伤的CT分级与NTCP密切相关。     

Exploring the effect of marked normal structure volume on normal tissue complication probability

Radiation therapy dosimetry software now frequently incorporates biological predictions of the probability of normal tissue complications. This study investigates whether the length of normal structure outlined affects a normal tissue complication probability (NTCP) for that structure. It also researches the effect of any change in the dose parameter used to produce a 50% probability of a complication (the TD⁵⁰) on the calculated NTCP, as this is related to the clinical observations. An NTCP was calculated for rectum and bladder on a sample of prostate cases receiving external beam radiation therapy. The length of the organs at risk was varied and the NTCP recalculated for each different length using the same treatment plan. Large variations of up to 80% in NTCP for different delineated lengths of organ for a given TD⁵⁰ were observed. Changing the TD⁵⁰ dose altered the calculated NTCP and the relative size of the variation in the values. This parameter will need further investigation; a standardized delineated length of 2 cm beyond the beam edge for normal structures is recommended. Interpatient and interinstitution plan comparison using dose volume histograms and/or normal tissue complication probabilities will be compromised until such standardization occurs.     

Osteoporotic vertebral compression fractures: a rare complication of radiotherapy in a patient with lung cancer

The development of bone fractures after radiotherapy is a rare event which mainly concerns the pelvis or the long bones. This complication is unusual in the vertebrae. We describe the case of a 66-year-old male patient with lung cancer who was treated with combined radio-chemotherapy and developed dorsal pain secondary to vertebral compression 4 months after the end of radiotherapy. Investigations led to a diagnosis of post-radiotherapy vertebral osteonecrosis. It is important to differentiate metastatic lesions from radiological complications. It is not possible to differentiate a metastasis from a recent osteoporotic compression fracture by imaging. A bone biopsy may therefore be necessary. Metastatic bone involvement is common in patients with lung cancer. When images are not typical of secondary progression, however, and there is no change in the general state of the patient, evidence of thoracic progression of the tumour or distal progression other than bone, vertebral osteoporotic complications should be considered. It is important that a wrong diagnosis is not made without histological proof of metastasis which has a poor prognosis.     

放射治疗IE期非结膜眼附属器黏膜相关淋巴组织型淋巴瘤的剂量效应和预后

目的 评价放射治疗IE期非结膜原发眼附属器黏膜相关淋巴组织型淋巴瘤的剂量效应和预后.方法 回顾性分析2003-11至2012-03收治的影像资料完整可测量33例(42只眼)IE期非结膜原发眼附属器黏膜相关淋巴组织型淋巴瘤患者资料. 结果 照射剂量18 Gy时与27 Gy时,依据WHO标准评价疗效,缓解率分别为31％和42.9％(P=0.258);依据RECIST标准评价疗效,缓解率分别为28.6和38.1％ (P =0.355).全组患者局部控制率100％.全组患者的5年、10年总生存(OS)率分别为96.8％和84.7％;5、10年无进展生存(PFS)率分别为89.6％和89.6％.接受≥30.6Gy组与27Gy组,5、10年总生存(OS)率分别为100％、80％和95.7％、95.7％ (P =0.8578);5、10年无进展生存(PFS)生存率分别为83.3％、83.3％和91.1％、91.1％ (P =0.6497). 结论 非结膜原发眼附属器黏膜相关淋巴组织型淋巴瘤对放射治疗敏感.从局部控制和长期生存的观察结果显示,27 Gy的照射剂量是足够的.探索最佳的照射剂量需要开展前瞻性大样本的剂量效应观察研究.     

The robustness of VMAT radiotherapy for breast cancer with tissue deformations

To investigate the near-surface doses and target coverage in modulated arc radiotherapy (RT) of the breast or chest wall in two treatment planning systems (TPS) in the presence of soft tissue deformations. This retrospective study consisted of 10 breast cancer patients with axillary lymph node inclusion. For each case, five RT plans were created: (1) tangential 3D conformal field-in-field (FinF) technique; (2) 200° to 240° arcs with optimization bolus (OB) in Eclipse (EB); (3) 243° to 250° arcs with an 8-mm OB in Monaco (MB); (4) 243° to 250° arcs with automatic skin flash tool (ASF) in Monaco TPS (MA); (5) 243° to 250° arcs with both ASF and OB in Monaco (MAB). Soft tissue deformation was simulated by editing CT-images with 4-, 8-, and 12-mm swelling and recalculating the dose. The increasing swelling from 0 to 12 mm caused the coverage (V95%) in clinical target volume to decrease from 96% ± 2% to 90% ± 6% for the FinF plans. For volumetric-modulated arc therapy (VMAT), the coverage decreased from 99% ± 1% to 92% ± 4% in the EB plans, and from 97% ± 1% to 68% ± 8%, 85% ± 6%, and 86% ± 5% for MA, MB, and MAB, respectively. The mean dose in the surface extending from 0 to 3 mm from the skin decreased on average 5%, 17%, 20%, 15%, and 8% in FinF, EB, MA, MB, and MAB, respectively. In the Monaco plans, the use of an OB(+ASF) provided better target coverage and lower dose maxima despite of tissue swelling than the ASF alone. With modulated arc therapy, we recommend the use of an OB instead of or in addition to the ASF. The use of 8 mm OB with VMAT plans is robust to account deformations extending outside up to 8mm. If soft tissue deformation is larger than 8 mm, the need for replanning should be evaluated.     

食管癌放射治疗中对正常组织的防护

放射治疗在食管癌的治疗中占有相当重要的地位。随着科学技术的发展与进步,人们在关心肿瘤杀伤情况的同时,越来越关注机体健康组织的辐射损伤程度。现从辐射防护的角度出发,简述在食管癌的放射治疗中运用重离子束、三维适形放射治疗和影像学指导的放射治疗等技术对食管周围正常组织的防护所做出的贡献。     

Colobronchial fistula: a late complication of childhood radiotherapy

We present the case of a colobronchial fistula in a 41-year-old man who underwent radiotherapy for nephroblastoma as an infant. He attended for barium enema, which demonstrated a fistula between colon and bronchial tree. Following right hemicolectomy and pathological examination of the resected bowel, no active disease process was identified to explain the development of this rare fistula. Radiotherapy was deemed the most probable aetiology. We are unaware of this having been previously described.     

The effect of 6 and 15 MV on intensity-modulated radiation therapy prostate cancer treatment: plan evaluation, tumour control probability and normal tissue complication probability analysis, and the theoretical risk of secondary induced malignancies

Objective

The aim of this study was to investigate the effect of 6 and 15-MV photon energies on intensity-modulated radiation therapy (IMRT) prostate cancer treatment plan outcome and to compare the theoretical risks of secondary induced malignancies.

Methods

Separate prostate cancer IMRT plans were prepared for 6 and 15-MV beams. Organ-equivalent doses were obtained through thermoluminescent dosemeter measurements in an anthropomorphic Aldersen radiation therapy human phantom. The neutron dose contribution at 15 MV was measured using polyallyl-diglycol-carbonate neutron track etch detectors. Risk coefficients from the International Commission on Radiological Protection Report 103 were used to compare the risk of fatal secondary induced malignancies in out-of-field organs and tissues for 6 and 15 MV. For the bladder and the rectum, a comparative evaluation of the risk using three separate models was carried out. Dose–volume parameters for the rectum, bladder and prostate planning target volume were evaluated, as well as normal tissue complication probability (NTCP) and tumour control probability calculations.

Results

There is a small increased theoretical risk of developing a fatal cancer from 6 MV compared with 15 MV, taking into account all the organs. Dose–volume parameters for the rectum and bladder show that 15 MV results in better volume sparing in the regions below 70 Gy, but the volume exposed increases slightly beyond this in comparison with 6 MV, resulting in a higher NTCP for the rectum of 3.6% vs 3.0% (p=0.166).

Conclusion

The choice to treat using IMRT at 15 MV should not be excluded, but should be based on risk vs benefit while considering the age and life expectancy of the patient together with the relative risk of radiation-induced cancer and NTCPs.Three-dimensional conformal radiation therapy (3D-CRT) is most commonly delivered with high-energy photons, typically in the range of 6–18 MV. Intensity-modulated radiation therapy (IMRT) is known to improve target coverage and provide better organ-at-risk (OAR) sparing in comparison with 3D-CRT [1]. However, IMRT is associated with an increase in the number of monitor units (MUs) relative to 3D-CRT, which has led to concerns about a potential increased risk of radiation-induced malignancies [2]. This risk becomes more relevant at higher photon energies (>10 MV), where there is a possibility of greater leakage radiation, treatment head scatter, patient scatter and photoneutron contribution [3]. Subsequently, the majority of IMRT treatments being delivered in the UK today use 6-MV photons. The use of higher energies for deep-seated tumours, such as those in the prostate, have been favoured by some as providing better dose coverage to the tumour target, while also improving normal tissue sparing [4].It has been reported in the literature that IMRT may double the risk of fatal second cancers compared with 3D-CRT [5-9]. The risk of fatal cancer has been reported for 6-MV 3D-CRT and IMRT prostate treatments to vary by 0.6–1.5% and 1–3.0%, respectively [7,8,10]. For 15-MV photons, the risk has been reported to be 3.4% [10]. These values have been computed using data from the National Council on Radiation Protection and Measurements (NCRP) Report 116, assuming a linear lifetime risk value of 0.05 per Sievert for all fatal radiation-induced cancers for the general population [11].There are as yet no epidemiological data for radiation-induced malignancy in patients with prostate cancer who received treatment with IMRT. A modest increase in second malignancies of 1 in 70 patients undergoing radiation and surviving for more than 10 years was reported for 3D-CRT, with the most common sites for secondary cancers being the bladder and rectum [12].Currently, at our centre (St Luke''s Cancer Centre, SLCC), 3D-CRT to the prostate is delivered mostly with 15-MV photons, whereas IMRT is delivered with 6-MV photons. During the initial set-up of prostate IMRT at SLCC, all energy beams (6, 10 and 15 MV) were in clinical use. After 10 patients had been treated, it was decided by the clinical team to use only 6-MV photons until the use of higher energy beams was further evaluated, given that the potential advantages related to their use could be offset by a potential increase in the risk of second malignancy.This study has investigated whether high-energy IMRT offers better target coverage and normal tissue sparing for prostate cancer. This work has investigated the organ equivalent doses through thermoluminescent dosemeter (TLD) measurements in an anthropomorphic Alderson radiation therapy (ART) human phantom (RANDO; The Phantom Laboratory, Salem, NY) in order to assess the theoretical risk of secondary malignancies in organs and tissues distant from the tumour target. For the bladder and rectum, a comparative evaluation of calculating the risk using the linear non-threshold model [13-15], linear-plateau model [16] and initiation–inactivation model [17] was performed. The neutron dose contribution at 15 MV was estimated using polyallyl-diglycol-carbonate (PADC) neutron track etch detectors. Dosimetric plan evaluations were carried out for the planning target volume (PTV) and OARs, as well as an assessment of the total number of MUs for plans generated with different energies.     

Estimation of lifetime attributable risks (LARs) of cancer associated with abdominopelvic radiotherapy treatment planning computed tomography (CT) simulations

Purpose: The present study attempts to calculate organ-absorbed and effective doses for cancer patients to estimate the possible cancer induction and cancer mortality risks resulting from 64-slice abdominopelvic computed tomography (CT) simulations for radiotherapy treatment planning (RTTP).

Material and methods: A group of 70 patients, who underwent 64-slice abdominopelvic CT scan for RTTP, voluntarily participated in the present study. To calculate organ and effective doses in a standard phantom of 70?kg, the collected dosimetric parameters were used with the ImPACT CT Patient Dosimetry Calculator. Patient-specific organ dose and effective dose were calculated by applying related correction factors. For the estimation of lifetime attributable risks (LARs) of cancer incidence and cancer-related mortality, doses in radiosensitive organs were converted to risks based on the data published in Biological Effects of Ionizing Radiation VII (BEIR VII).

Results: The mean?±?standard deviation (SD) of the effective dose for males and females were 13.87?±?2.37 mSv (range: 9.25–18.82 mSv) and 13.04?±?3.42 mSv (range: 6.99–18.37 mSv), respectively. The mean?±?SD of LAR of cancer incidence was 35.34?±?13.82 cases in males and 34.49?±?9.63 cases in females per 100,000 persons. The LAR of cancer mortality had the mean?±?SD value of 15.38?±?4.25 and 16.72?±?3.87 cases per 100,000 persons in males and females respectively.

Conclusion: Increase in the LAR of cancer occurrence and mortality due to abdominopelvic treatment planning CT simulation is noticeable and should be considered.     

覆膜内支架治疗食管癌放疗后狭窄及食管气管瘘临床分析

目的评价覆膜食管内支架治疗食管癌放疗后狭窄及食管气管瘘的临床效果。方法本组89例食管癌放疗后狭窄及食管气管瘘的患者,其中并发食管气管瘘28例。食管内覆膜支架置入均在数字减影血管造影机(DSA)监视下进行。结果 89例患者均成功置入覆膜内支架,27例中上段食管气管瘘完全被封闭,进水呛咳症状消失。18例术后再狭窄,再次置入支架。结论食管覆膜内支架治疗食管癌放疗后狭窄及食管气管瘘安全有效,能提高患者生活质量,延长生存期。     

Single-arc volumetric-modulated arc therapy (sVMAT) as adjuvant treatment for gastric cancer: Dosimetric comparisons with three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT)

To compare the dosimetric differences between the single-arc volumetric-modulated arc therapy (sVMAT), 3-dimensional conformal radiotherapy (3D-CRT), and intensity-modulated radiotherapy (IMRT) techniques in treatment planning for gastric cancer as adjuvant radiotherapy. Twelve patients were retrospectively analyzed. In each patient's case, the parameters were compared based on the dose-volume histogram (DVH) of the sVMAT, 3D-CRT, and IMRT plans, respectively. Three techniques showed similar target dose coverage. The maximum and mean doses of the target were significantly higher in the sVMAT plans than that in 3D-CRT plans and in the 3D-CRT/IMRT plans, respectively, but these differences were clinically acceptable. The IMRT and sVMAT plans successfully achieved better target dose conformity, reduced the V_20/30, and mean dose of the left kidney, as well as the V_20/30 of the liver, compared with the 3D-CRT plans. And the sVMAT technique reduced the V₂₀ of the liver much significantly. Although the maximum dose of the spinal cord were much higher in the IMRT and sVMAT plans, respectively (mean 36.4 vs 39.5 and 40.6 Gy), these data were still under the constraints. Not much difference was found in the analysis of the parameters of the right kidney, intestine, and heart. The IMRT and sVMAT plans achieved similar dose distribution to the target, but superior to the 3D-CRT plans, in adjuvant radiotherapy for gastric cancer. The sVMAT technique improved the dose sparings of the left kidney and liver, compared with the 3D-CRT technique, but showed few dosimetric advantages over the IMRT technique. Studies are warranted to evaluate the clinical benefits of the VMAT treatment for patients with gastric cancer after surgery in the future.     

The UKNG database: a simple audit tool for interventional neuroradiology

Introduction The UK Neurointerventional Group (UKNG) has developed a unified database for the purposes of recording, analysis and clinical audit of neuroangiography and neurointerventional procedures. It has been in use since January 2002. Methods The database utilizes an Access platform (Microsoft) comprising separate but linked programs for data collection and analysis. The program that analyses aneurysm therapy has been designed to mirror the criteria used in the International Subarachnoid Aneurysm Trial (ISAT). Results Data entered into the main database immediately update the analysis program producing clinical outcome scores in the form of a report. Our local database (Wessex) now contains records on more than 1,750 patients including nearly 350 aneurysm coilings and a total of approximately 500 neurointerventional, vascular procedures. Every time a new piece of information is added to the main database the reporting database is automatically updated which allows ‘real-time’ audit and analysis of one’s clinical practice. The clinical outcome scores for aneurysm treatment are presented in such a way that we can directly compare our results with the ‘Clinical Standard’ set by ISAT. Conclusion This database provides a unique opportunity to monitor and review practice at national level. The UKNG wishes to share this database with the wider neurointerventional community and a copy of the software can be obtained free of charge from the authors.     

Early clinical evaluation of a novel three-dimensional structure delineation software tool (SCULPTER) for radiotherapy treatment planning

Modern radiotherapy treatment planning (RTP) necessitates increased delineation of target volumes and organs at risk. Conventional manual delineation is a laborious, time-consuming and subjective process. It is prone to inconsistency and variability, but has the potential to be improved using automated segmentation algorithms. We carried out a pilot clinical evaluation of SCULPTER (Structure Creation Using Limited Point Topology Evidence in Radiotherapy) - a novel prototype software tool designed to improve structure delineation for RTP. Anonymized MR and CT image datasets from patients who underwent radiotherapy for bladder or prostate cancer were studied. An experienced radiation oncologist used manual and SCULPTER-assisted methods to create clinically acceptable organ delineations. SCULPTER was also tested by four other RTP professionals. Resulting contours were compared by qualitative inspection and quantitatively by using the volumes of the structures delineated and the time taken for completion. The SCULPTER tool was easy to apply to both MR and CT images and diverse anatomical sites. SCULPTER delineations closely reproduced manual contours with no significant volume differences detected, but SCULPTER delineations were significantly quicker (p<0.05) in most cases. In conclusion, clinical application of SCULPTER resulted in rapid and simple organ delineations with equivalent accuracy to manual methods, demonstrating proof-of-principle of the SCULPTER system and supporting its potential utility in RTP.     

Palliative treatment with high-dose-rate endobronchial interventional radiotherapy (Brachytherapy) for lung cancer patients

PURPOSE: to report on the use of high-dose-rate (HDR) endobronchial interventional radiotherapy (brachytherapy, EBIRT) for palliation of symptoms in patients with lung cancer.PATIENTS AND METHODS: retrospective review of lung cancer patients treated with HDR-EBIRT at our institution (1995–2017). Treatment results and treatment related toxicity were recorded. Clinical response was subjectively evaluated within 3 months after treatment. Overall survival (OS) was analyzed.RESULTS: 347 patients were identified. The median age was 69 years and the median follow-up time was 13.4 months. Most patients received external beam radiation therapy during the primary treatment. Within 3 months, 87.7% of the patients had complete or major response of their presenting symptoms. OS was 55.2% at 1 year, 18.3% at 2 years. Patients who had complete or major response had a longer median survival than other patients (13 versus 7 months, p = 0.03). Chronic bronchitis was found in 26.8%, while 7.8% of the patients died due to uncontrollable hemoptysis.CONCLUSION: HDR-EBIRT is a safe and effective treatment option for the palliative treatment of lung cancer patients. HDR-EBIRT is most suitable as a re-irradiation technique. Further clinical studies are needed to validate its role.