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Abstract Background This study aimed to establish a consensus on the delineation of target volumes for neoadjuvant radiation therapy (nRT) in esophageal squamous cell carcinoma (ESCC) within China. Methods From February 2020 to June 2021, nine ESCC patients who received nRT were retrospectively selected from Sun Yat-sen University Cancer Center and Shandong Cancer Hospital. A panel from eight cancer radiotherapy centers performed two rounds of nRT target volume delineation for these patients: the first round for cases 1–6 and the second for cases 7–9. Online meetings were held after each delineation round to discuss findings. The consistency of delineations across centers was compared using mean undirected Hausdorff distances (Hmean), dice similarity coefficients (DSC), and total volumes, analyzed with the Mann-Whitney U test. Results The second round of delineations showed improved consistency across centers (total clinical target volume (CTVtotal): mean DSC = 0.76–0.81; mean Hmean = 2.11–3.14 cm) compared to the first round (CTVtotal: mean DSC = 0.63–0.64; mean Hmean = 5.66–7.34 cm; DSC and Hmean: P

Introduction: 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) is recommended for staging and defining target volume in limited-stage SCLC, though the impact on outcomes compared with CT staging and elective nodal irradiation (ENI) is not well documented. We analyzed patients receiving 45 Gy/30 fractions in two randomized trials of thoracic radiotherapy (TRT) in limited-stage SCLC (HAST and THORA trials) to evaluate whether PET-CT for staging and radiotherapy planning reduces radiotoxicity and improves survival. Methods: Patients in HAST were staged with CT of the thorax and upper abdomen and brain magnetic resonance imaging of the brain. Patients in THORA were staged with PET-CT in addition. All patients were to receive four courses of platinum/etoposide chemotherapy and concurrent TRT starting three to four weeks after the first chemotherapy course. In HAST, target volumes included pathological lesions on CT plus ENI of lymph node stations 4–7 (bilateral). In THORA, target volumes were limited to PET-CT-positive lesions (selective nodal irradiation [SNI]). Results: A total of 149 patients were included (PET-CT/SNI: n = 76, CT/ENI: n=73); the median age was 64 years, 56% were women, 85% had PS 0 to 1, and 81% had stage III disease. The PET-CT/SNI group experienced less grade 3-4 esophagitis (18% versus 33%, p = 0.043), less grade >=1 pneumonitis (5% versus 16%, p = 0.028), and less dysphagia after TRT (mean scores on European Organisation for Research and Treatment of Cancer 13-item lung cancer module: 45 versus 72). There was no difference in median overall survival (24 versus 25 mo, p = 0.59) or progression-free survival (11 versus 11 mo, p = 0.23). Conclusions: Using PET-CT for staging and target volume definition of TRT reduces acute radiotoxicity but does not improve overall or progression-free survival in limited-stage SCLC.

Abstract Nasopharyngeal carcinoma(NPC) occurs frequently in Southern China, and radiotherapy is the main treatment method. At present, intensity‐modulated radiotherapy is widely used, which has improved efficacy in patients with NPC and reduced toxicity and side effects. Recently, helical tomography radiotherapy, proton radiotherapy, carbon particle radiotherapy, and other radiotherapy techniques have been used for the clinical treatment of NPC. Individualized nasopharyngeal cancer targets have also been explored. This paper reviews the research progress in radiotherapy techniques and target volume for NPC

Abstract Background Supraclavicular nodal (SCL) irradiation is commonly used for patients with high-risk breast cancer after breast surgery. The Radiation Therapy Oncology Group (RTOG) and European Society for Radiotherapy and Oncology (ESTRO) breast contouring atlases delineate the medial part of the SCL region, while excluding the posterolateral part. However, recent studies have found that a substantial proportion of SCL failures are located in the posterolateral SCL region, outside of the RTOG/ESTRO-defined SCL target volumes. Consequently, many radiation oncologists advocate for enlarging the SCL irradiation target volume to include both the medial and posterolateral SCL regions. Nevertheless, it remains uncertain whether adding the posterolateral SCL irradiation improves survival outcomes for high-risk breast cancer patients. Methods The SUCLANODE trial is an open-label, multicenter, randomized, phase 3 trial comparing the efficacy and adverse events of medial SCL irradiation (M-SCLI group) and medial plus posterolateral SCL irradiation (entire SCL irradiation, E-SCLI group) in high-risk breast cancer patients who underwent breast conserving-surgery or mastectomy. Patients with pathological N2-3b disease following initial surgery, or clinical stage III or pathological N1-3b if receiving neoadjuvant systemic therapy, are eligible and randomly assigned (1:1) to M-SCLI group and E-SCLI group. Stratification is by chemotherapy sequence (neoadjuvant vs. adjuvant), T stage (T3-4 vs. T1-2), N stage (N1-2 vs. N3), and ER status (positive vs. negative). Other radiation volumes are identical in the two arms, including breast/chest wall, undissected axillary lymph node, and internal mammary node. Advanced intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT), or tomotherapy techniques are recommended. Both hypofractionated and conventional fractionation schedules are permitted. The primary end point is invasive disease-free survival, and secondary end points included overall survival, SCL recurrence, local-regional recurrence, distance recurrence, safety outcome, and patient-reported outcomes. The target sample size is 1650 participants. Discussion The results of the SUCLANODE trial will provide high-level evidence regarding whether adding posterolateral SCL irradiation to medial SCL target volume provides survival benefit in patients with high-risk breast cancer. Trial registration ClinicalTrials.gov Identifier: NCT05059379. Registered 28 September 2021, https://www.clinicaltrials.gov/ct2/show/NCT05059379 .

Abstract Purpose Radiotherapy is, with surgery, one of the main therapeutic treatment strategies for meningiomas. No prospective study has defined a consensus for the delineation of target volumes for meningioma radiotherapy. Therefore, target volume definition is mainly based on information from retrospective studies that include heterogeneous patient populations. The aim is to describe delineation guidelines for meningioma radiotherapy as an adjuvant or definitive treatment with intensity-modulated radiation therapy and stereotactic radiation therapy techniques. This guideline is based on a consensus endorsed by a multidisciplinary group of brain tumor experts, members of the Association of French-speaking Neuro-oncologists (ANOCEF). Materials and methods A 3-step procedure was used. First, the steering group carried out a comprehensive review to identify divergent issues on meningiomas target volume delineation. Second, an 84-item web-questionnaire has been developed to precisely define meningioma target volume delineation in the most common clinical situations. Third, experts members of the ANOCEF were requested to answer. The first two rounds were completed online. A third round was carried out by videoconference to allow experts to debate and discuss the remaining uncertain questions. All questions remained in a consensus. Results Limits of the target volume were defined using visible landmarks on computed tomography and magnetic resonance imaging, considering the pathways of tumor extension. The purpose was to develop clear and precise recommendations on meningiomas target volumes. Conclusion New recommendations for meningiomas delineation based on simple anatomic boundaries are proposed by the ANOCEF. Improvement in uniformity in target volume definition is expected.

Background and purpose: The standard treatment for patients with locally advanced esophageal cancer is neoadjuvant chemoradiotherapy (NCRT) plus radical resection. However, the technical aspects for implementing this comprehensive treatment strategy differ, especially in the controversial definition of the radiotherapy target area in NCRT. This study aimed to analyze the feasibility of involving field irradiation (IFI) in NCRT for locally advanced esophageal cancer. Methods: Retrospective analysis of locally advanced esophageal squamous cell carcinoma patients receiving NCRT in Shanghai Chest Hospital, Shanghai Jiao Tong University School of Medicine from July 2016 to May 2017 showed that the radiotherapy target of all patients was our recommended IFI. The radiotherapy plan was redesigned for the enrolled patients according to the two traditional target delineation of elective node irradiation (ENI) and primary subclinical lesion irradiation (SLI). The dosimetric parameters of the three groups and the dose differences of organ at risk (OAR), such as lungs, heart and spinal cord, were compared, and the relationship between IFI Recurrence pattern and radiation target volumes was analyzed. Results: A total of 26 patients were enrolled. The average target volume of IFI was (277±77) cm3, which was significantly lower compared with ENI and SLI (P

Incidence of carcinoma esophagus accounts for approximately 6% of all gastrointestinal malignancies. According to GLOBOCAN 2020 data, 604,100 cases of carcinoma esophagus were detected (3.1% of total cases), and it was the 8th most common cancer in the world. The first choice of treatment for resectable esophageal cancer is surgery. Neoadjuvant radio-chemotherapy improved the overall survival (OS) of patients with advanced carcinomas of the esophagus by about 10% in 5 years, as shown by different studies. In unresectable cases, carcinoma esophagus definitive chemoradiation is the treatment of choice. Determination of the target volume of the esophagus has changed with time due to the advancement of technology. Determining the target volumes accurately is essential to achieve precise dose delivery to the targets. Controversies still exist between different regions and societies regarding target volume determination. However, the choice of the treatment volumes, techniques, and dose for optimal use must be individualized. Patients' disease status, preference, and comorbidities should also be considered while making decisions. This article will review the different target volumes, techniques, and doses used in various large trials used in definitive, neoadjuvant, and adjuvant studies.

Abstract Background Gallbladder cancer (GBC) is an uncommon malignancy with high recurrent rate and poor prognosis. This study investigates the recurrent patterns of postoperative GBC, with the aim to guide the adjuvant treatments, including the radiotherapy. Methods Retrospectively analyzed the 109 GBC patients who underwent surgery in our institution from January 2013 to 2018. Clinical follow-up revealed 54 recurrent cases, of which 40 had detailed locations of recurrence. The sites of recurrence were recorded and divided into the tumor bed, corresponding lymphatic drainage area, intrahepatic recurrence, and the other distant metastasis. Results The median follow-up time is 34 months (IQR: 11–64). The median disease-free survival (DFS) and overall survival (OS) were 48.8 months and 53.7 months, respectively. Through univariate analysis, risk factors for DFS and OS include tumor markers (CA199 and CEA), hepatic invasion, perineural invasion, lymphovascular invasion, TNM staging and tumor differentiation. Through multivariate analysis, risk factors for DFS include hepatic invasion and TNM staging, and for OS is TNM staging only. Of the 40 cases with specific recurrent sites, 29 patients (29/40, 72.5%) had recurrence in the potential target volume of postoperative radiotherapy (PORT), which include tumor bed and corresponding lymphatic drainage area. The common recurrent lymph node groups included abdominal para-aortic lymph node (No.16, 15/29), hepatoduodenal ligament lymph node (No.12, 8/29), retro-pancreatic head lymph node (No.13, 7/29) and celiac axis lymph node (No.9, 4/29). Twenty cases with recurrences inside the potential PORT target volume were accompanied by distant metastasis. Another 11 cases had distant metastasis alone, so totally 31 cases developed distant metastasis (31/40, 77.5%), including 18 cases with hepatic metastasis. Conclusion The recurrence and metastasis rates are high in GBC and adjuvant therapy is needed. Up to 75% of the recurrent cases occurred in the potential target volume of postoperative radiotherapy, suggesting that postoperative radiotherapy has the possible value of improving local-regional control. The potential target volume of radiotherapy should include the tumor bed, No.8, No.9, No.11, No.12, No.13, No.14, No. 16a2, No. 16b1 lymph node groups.

Introduction: High Dose Rate (HDR) brachytherapy plays an important role in the treatment of lung carcinoma. The treatment of lung carcinoma with Endobronchial Brachytherapy Treatment (EBBT) is delivered with three fractions and the effect of EBBT on the Target Volume (TV) after delivering the three fractions in the lung carcinoma needs to be assessed. The TV is covered with the prescribed dose and Organs At Risk (OARs) doses are evaluated. Aim: To assess the doses to OAR nearby the tumour and analyse the effect of the TV, tumour location, and site on the doses to OARs in EBBT in lung carcinoma. Materials and Methods: A cross-sectional study was conducted in the Department of Radiation Oncology, Cancer Research Institute, Himalayan Institute of Medical Sciences, Swami Rama Himalayan University Dehradun, Uttarakhand, India, from January 2018 to December 2020. Thirty patients with lung carcinoma were included in dosimetric and volumetric assessments. A flexible lumencare catheter was inserted into the bronchial lesion. Computed Tomography (CT) scan was acquired and exported to Treatment Planning System (TPS) through Digital Imaging and Communications in Medicine (DICOM) networking system. An optimised treatment plan was generated. The TV and OARs were delineated on the CT scan of the patient. A total of three EBBT sessions were given with a 7 Gy dose per fraction and prescribed the dose at 1.0 cm from the center of the catheter. Doses to OARs and the effects of TV on doses to OARs were evaluated with the help of “Dose Volume Histogram (DVH) tool” in the TPS. Thirty patients, with varying TV and site, were grouped as left lung and right lung tumour lesions and also grouped as TV 22 cc for the analysis purpose in this study. The data was entered in Microsoft Office Excel 2007 and analysed in Statistical Package for the Social Sciences (SPSS) version 22.0 statistical analysis software (IBM Corp., Armonk, N.Y., USA) tool. Results: The mean doses to OARs in 1st, 2nd and 3rd EBBT sessions were within their tolerance limit. The mean dose difference between left and right lung tumour site were analysed and found mainly the mean dose to oesophagus and maximum dose to oesophagus, contralateral lung, left coronary artery and descending aorta were significantly higher in left lung compared to right lung with p-value 0.015, 0.027, 0.001, 0.007 and 0.001, respectively. The maximum dose to the contralateral lung and spinal cord were significantly higher in middle-lower bronchial lesion with p-value 0.024 and 0.023, respectively. The mean dose difference between left and right lung tumour volume for TV 22 cc was analysed and found mainly for the group TV>22 cc the mean dose to oesophagus and maximum dose to oesophagus, Heart, contralateral lung, left coronary artery and descending aorta were significantly higher in the left lung compared to right lung with p-value 0.002, 0.008, 0.027, 0.003, 0.006 and 0.001, respectively whereas in the TV

The aim of this study is to examine the precision of semi-automatic, conventional and automatic volumetry tools for pulmonary nodules in chest CT with phantom N1 LUNGMAN. The phantom is a life-size anatomical chest model with pulmonary nodules representing solid and subsolid metastases. Gross tumor volumes (GTVis) were contoured using various approaches: manually (0); as a means of semi-automated, conventional contouring with (I) adaptive-brush function; (II) flood-fill function; and (III) image-thresholding function. Furthermore, a deep-learning algorithm for automatic contouring was applied (IV). An intermodality comparison of the above-mentioned strategies for contouring GTVis was performed. For the mean GTVref (standard deviation (SD)), the interquartile range (IQR)) was 0.68 mL (0.33; 0.34–1.1). GTV segmentation was distributed as follows: (I) 0.61 mL (0.27; 0.36–0.92); (II) 0.41 mL (0.28; 0.23–0.63); (III) 0.65 mL (0.35; 0.32–0.90); and (IV) 0.61 mL (0.29; 0.33–0.95). GTVref was found to be significantly correlated with GTVis (I) p < 0.001, r = 0.989 (III) p = 0.001, r = 0.916, and (IV) p < 0.001, r = 0.986, but not with (II) p = 0.091, r = 0.595. The Sørensen–Dice indices for the semi-automatic tools were 0.74 (I), 0.57 (II) and 0.71 (III). For the semi-automatic, conventional segmentation tools evaluated, the adaptive-brush function (I) performed closest to the reference standard (0). The automatic deep learning tool (IV) showed high performance for auto-segmentation and was close to the reference standard. For high precision radiation therapy, visual control, and, where necessary, manual correction, are mandatory for all evaluated tools.

To analyze the dosimetric effects of shoulder position shift on target volumes and organs at risk (OARs) during radiotherapy for head and neck cancer, 14 patients with different types of head and neck cancer were selected. Based on original positioning CTs (o-CTs), the shoulder position was moved toward the superior inferior (SI) direction, anterior posterior (AP) direction, and the left right (LR) direction by 3 mm, 6 mm, and 15 mm, then 252 new CTs (n-CTs) were produced. After setting the movement, the new adipose tissue density was set to 1 g/cm3, and the movement of the bone tissue was also considered. The original plan (o-plan) on the o-CT was copied to the n-CTs and recalculated to obtain 252 new plans (n-plans). The differences between the o-plan and n-plan target volumes and OARs in field-fixed intensity modulated radiotherapy and the volumetric modulated arc intensity (VMAT) were studied, and the dose changes of the target volume D95% and spinal cord Dmax were compared with the movement of the shoulder position. It was proved that the effects of the shoulder position shift on the target volume and OARs for head and neck cancers are substantial, especially a 15 mm shift toward the superior direction had the greatest influence, reaching 4.16% (VMAT). The closer the target area is to the shoulder, the more serious the impact. The spinal cord dose increased greatly, reaching a maximum of 72.8 cGy, 100 cGy and 212 cGy (VMAT), respectively, for shift of 3 mm, 6 mm, and 15 mm towards the inferior direction. The o-plan and p-plan were analyzed using a 3D γ passing rate (3%/3 mm), that was more than 95% except for the 15 mm shift towards the superior direction. Radiotherapy technicians should pay attention to ensure that the shoulder is lightly touching the thermoplastic mold during radiotherapy positioning for head and neck tumors to prevent patients from shrugging their shoulders. The OAR dose limit should be considered in the planning design, and a sufficient margin should be left to prevent the excessive dose caused by the positioning.

Abstract Purpose To determine which imaging method used during radioembolization (RE) work-up: contrast-enhanced computed tomography (CECT), 99mTc-MAA-SPECT/CT or cone beam-CT (CBCT), more accurately predicts the final target volume (TgV) as well as the influence that each modality has in the dosimetric calculation. Methods TgVs from 99mTc-MAA-SPECT/CT, CECT and CBCT were consecutively obtained in 24 patients treated with RE and compared with 90Y PET/CT TgV. Using the TgVs estimated by each imaging modality and a fictitious activity of 1 GBq, the corresponding absorbed doses by tumor and non-tumoral parenchyma were calculated for each patient. The absorbed doses for each modality were compared with the ones obtained using 90Y PET/CT TgV. Results 99mTc-MAA-SPECT/CT predicted 90Y PET/CT TgV better than CBCT or CECT, even for selective or superselective administrations. Likewise, 99mTc-MAA-SPECT/CT showed dosimetric values more similar to those obtained with 90Y PET/CT. Nevertheless, CBCT provided essential information for RE planning, such as ensuring the total coverage of the tumor and, in cases with more than one feeding artery, splitting the activity according to the volume of tumor perfused by each artery. Conclusion The joint use of 99mTc-MAA-SPECT/CT and CBCT optimizes dosimetric planning for RE procedures, enabling a more accurate personalized approach.

Advances in radiation technology, such as intensity-modulated radiation therapy (IMRT), have largely enabled a biological dose escalation of the target volume (TV) and reduce the dose to adjacent tissues or organs at risk (OARs). However, the risk of radiation-induced injury increases as more radiation dose utilized during radiation therapy (RT), which predominantly limits further increases in TV dose distribution and reduces the local control rate. Thus, the accurate target delineation is crucial. Recently, technological improvements for precise target delineation have obtained more attention in the field of RT. The addition of functional imaging to RT can provide a more accurate anatomy of the tumor and normal tissues (such as location and size), along with biological information that aids to optimize the therapeutic index (TI) of RT. In this review, we discuss the application of some common MRI-based functional imaging techniques in clinical practice. In addition, we summarize the main challenges and prospects of these imaging technologies, expecting more inspiring developments and more productive research paths in the near future.

Abstract Background To explore the patterns of failures and areas at highest risk of recurrence for postoperative intrahepatic cholangiocarcinoma (IHCC), with the aim to guide IHCC adjuvant radiotherapy. Methods Patients with IHCC who had undergone radical surgery at our institution from July 2010 to August 2017 were retrospectively analyzed. The survival and prognostic factors were analyzed by univariate and multivariate analysis. All sites of recurrence were found out and classified as the surgical margin, regional lymph nodes, liver remnant and distant metastasis. According to the recurring area at highest risk, the target volume of adjuvant radiotherapy was proposed. Results The median follow-up time was 23.5 months (2–85 months). The median recurrence free survival (RFS) and overall survival (OS) were 12.1 months and 24.8 months, respectively. Seventy-three (73/127, 57.5%) IHCC patients developed tumor recurrence. Initial recurrences occurred in the potential postoperative radiotherapy (PORT) volume, remnant liver and distant sits were 46 (46/73, 63.0%), 36 (36/73, 49.3%) and 22 (22/73, 30.1%) cases, respectively. Of the 46 patients whose initial recurrence inside the potential PORT volume, 29 (29/73, 39.7%) developed recurrence only inside the potential PORT volume, including 13 tumor bed recurrences, 7 lymph node metastases, and 9 with both tumor bed recurrences and lymph node metastases. The most common lymph node metastases sites were nodes around the abdominal aorta, followed by lymph nodes along the celiac artery, the common hepatic artery, and in the hepatoduodenal ligament. Conclusions High proportion of the recurrences occurred only inside the potential PORT volume, implying adjuvant radiotherapy might improve the local-regional control. Surgical margins and lymph node stations No.16a2, 9, 8, 12, 13, and 14 are suggested to be included in the radiation volume.

Abstract Background There are different contouring guidelines for the clinical target volume (CTV) in anal cancer (AC) which vary concerning recommendations for radiation margins in different anatomical regions, especially on inguinal site. PET imaging has become more important in primary staging of AC as a very sensitive method to detect lymph node (LN) metastases. Using PET imaging, we evaluated patterns of LN spread, and examined the differences of the respective contouring guidelines on the basis of our results. Methods We carried out a retrospective study of thirty-seven AC patients treated with chemoradiation (CRT) who underwent FDG-PET imaging for primary staging in our department between 2011 and 2018. Patients showing PET positive LN were included in this analysis. Using a color code, LN metastases of all patients were delineated on a template with “standard anatomy” and were divided indicating whether their location was in- or out-field of the standard CTV as recommended by the Radiation Therapy Oncology Group (RTOG), the Australasian Gastrointestinal Trials Group (AGITG) or the British National Guidance (BNG). Furthermore, a detailed analysis of the location of LN of the inguinal region was performed. Results Twenty-two out of thirty-seven AC patients with pre-treatment PET imaging had PET positive LN metastases, accumulating to a total of 154 LN. The most commonly affected anatomical region was inguinal (49 LN, 32%). All para-rectal, external/internal iliac, and pre-sacral LN were covered by the recommended CTVs of the three different guidelines. Of forty-nine involved inguinal LN, fourteen (29%), seven (14%) and five (10%) were situated outside of the recommended CTVs by RTOG, AGITG and BNG. Inguinal LN could be located up to 5.7 cm inferiorly to the femoral saphenous junction and 2.8 cm medial or laterally to the big femoral vessels. Conclusion Pelvis-related, various recommendations are largely consistent, and all LN are covered by the recommended CTVs. LN “misses” appear generally cranially (common iliac or para-aortic) or caudally (inguinal) to the recommended CTVs. The established guidelines differ significantly, particular regarding the inguinal region. Based on our results, we presented our suggestions for CTV definition of the inguinal region. LN involvement of a larger number of patients should be investigated to enable final recommendations.

Background: Radiotherapy plays an important role in the management of cancer. Although the improved technologies increase therapeutic index, different delivery techniques deliver different dose pattern to the healthy tissue within and outside treatment volume. Objective: The objective of this study was to evaluate the low, intermediate, and high dose to healthy tissue within and outside the treatment volume and to find the relation between tumor volume and various doses received healthy tissue volume. Materials and Methods: A total of 150 patients were included. For all patients, planning computed tomography images were acquired. Tumors, critical structures, and healthy tissue volumes at different regions were delineated. Two sets of plans, one with volumetric-modulated arc therapy and another with intensity-modulated radiation therapy (IMRT) were created, optimized for 6 MV photons and dose was calculated. Dosimetry results for tumor, organs at risks (OARs), and healthy tissue from both the techniques were evaluated and compared. Results: Tumor coverage and dose to OARs was significantly better with volumetric-modulated arc therapy (VMAT). Volume of healthy tissue received high-dose within the treatment volume as well as volume of healthy tissue received low and intermediate-dose out of treatment volume were significantly (P < 0.002) lesser with VMAT. Besides, the results showed that as the tumor volume increased, the various dose received healthy tissue volume also increased. Conclusions: VMAT plan can reduce the risk of secondary malignancy while treating different sites of cancer. VMAT is the most appropriate technique than IMRT, especially in the treatment of large tumor volume. Special attention has to be given, especially while treating women and children.

Abstract Background Definitive chemoradiotherapy is standard of care in locally advanced cervical cancer (LACC). Both toxicity and local relapse remain major concerns in this treatment. We hypothesize that a magnetic resonance imaging (MRI) based redefining of the radiotherapeutic target volume will lead to a reduction of acute and late toxicity. In our center, chemoradiotherapy followed by hysterectomy was implemented successfully in the past. This enables us to assess the safety of reducing the target volume but also to explore the biological effects of chemoradiation on the resected hysterectomy specimen. Methods The EXIT-trial is a phase II, single arm study aimed at LACC patients. This study evaluates whether a MRI-based exclusion of the non-tumor-bearing parts of the uterus out of the target volume results in absence of tumor in the non-high doses irradiated part of the uterus in the hysterectomy specimen. Secondary endpoints include a dosimetric comparison of dose on normal tissue when comparing study treatment plans compared to treatment of the whole uterus at high doses; acute and chronic toxicity, overall survival, local relapse- and progression-free survival. In the translational part of the study, we will evaluate the hypothesis that the baseline apparent diffusion coefficient (ADC) values of diffusion weighted MRI and its evolution 2 weeks after start of CRT, for the whole tumor as well as for intra-tumoral regions, is prognostic for residual tumor on the hysterectomy specimen. Discussion Although MRI is already used to guide target delineation in brachytherapy, the EXIT-trial is the first to use this information to guide target delineation in external beam radiotherapy. Early therapy resistance prediction using DW-MRI opens a window for early treatment adaptation or further dose-escalation on tumors/intratumoral regions at risk for treatment failure. Trial registration Belgian Registration: B670201526181 (prospectively registered, 26/11/2015); ClinicalTrials.gov Identifier: NCT03542942 (retrospectively registered, 17/5/2018).

Introduction/Objective. The aim of this study was to dosimetric comparison of two-dimensional (2D) with three-dimensional (3D) planning for high-dose-rate intracavitary brachytherapy (HDR-BT) in locally advanced cervical cancer by dose evaluation in given International Commission on Radiation Units and Measurements (ICRU) reference points, as well as in target volume and organs at risk (OAR). Methods. 66 sessions of HDR-BT were performed in 22 patients, with 3D planning, but also virtual 2D plan for dosimetric comparison was made. 2D planning was performed on radiography obtained by C-arm in ICRU points, while 3D planning in volumes delineated on computer tomography. Results. The comparative analysis has indicated a significant mean dose difference of point “A” left (p=0.00014) and right (p=0.003), through higher doses in 2D and lower doses in 3D reconstructed points "A". According to the dose volume histograms 56.88% and 61.41% mean target volume received 100% and 90% of prescribed dose, respectively. 2D bladder analysis showed a mean dose of 3.487 Gy in ICRU point, while in 3D analysis a maximum mean dose of 8.804 Gy and mean dose of 4.716 Gy in 2ccm volume. 2D analysis showed rectal mean dose of 2.892 Gy in ICRU points, while 3D analysis maximum mean dose of 6.411 Gy and 3.947 Gy mean dose in 2ccm volume. Conclusion. 2D planning showed unreal higher doses in the ICRU points for the target and lower doses for the OAR.

Abstract Background The aim was to evaluate the geometric and corresponding dosimetric differences between two delineation strategies for head and neck tumors neighboring air cavities. Methods Primary gross and clinical tumor volumes (GTV and CTV) of 14 patients with oropharynx or larynx tumors were contoured using a soft tissue window (S). In a second strategy, the same volumes were contoured with an extension to include the parts which became visible on lung window (L). For the calculation of Hausdorff-distances (HD) between contoured volumes of the two strategies, triangular meshes were exported. Two radiotherapy plans with identical goals and optimization parameters were generated for each case. Plan_S were optimized on CTV_S, and Plan_L on CTV_L. The dose coverages of CTV_L and CTV_Δ (CTV_L minus CTV_S) were evaluated in Plan_S. OAR doses were compared among Plan_S and Plan_L. Results Median three-dimensional HD for GTVs and CTVs were 5.7 (±2.6) and 9.3 (±2.8) mm, respectively. The median volume differences between structures contoured using L and S windows were 9% (±5%) and 9% (±4%) for GTV and CTV, respectively. In 13 out of 14 cases, Plan_S met the plan acceptance criteria for CTV_L. In 8 cases CTV_Δ was covered insufficiently in Plan_S. Mean and median differences in OAR dose-volume histogram parameters between Plan_S and Plan_L were within 3%. Conclusion For the current practice in radiotherapy planning for head and neck cancer, the delineation of L-based volumes seems unnecessary. However, in special settings, where smaller or no PTV margins are used, this approach may play an important role for local control.

Abstract Background To evaluate the dosimetric performance of multi-channel vaginal cylinder (MCVC) against interstitial brachytherapy (ISBT) for the treatment of vaginal tumors. Methods Vaginal tumors with extension of > 0.5 cm and ≤ 2 cm from the lateral vaginal wall and/or ≤ 1 cm in height above the vaginal vault were retrospectively selected from a ISBT registry trial database. The selected patients were treated with ISBT and targets included the intermediate (IRCTV) or high-risk (HRCTV) clinical target volumes. For technique comparison, a 35 mm MCVC was registered with the interstitial intra-vaginal cylinder. Bladder and rectum contours were transferred from the ISBT to the MCVC-BT plans. Vaginal mucosa was achieved by 3 mm uniform expansion from cylinder surface. Both the ISBT and MCVC-BT plans were optimized using the Inverse Planning Simulated Annealing optimization algorithm. After normalizing target D90 to 700 cGy, dose to organs at risk were measured and compared between ISBT and MCVC plans. Results Six interstitial patient plans met the inclusion criteria for this study. Four patients had vaginal primaries and two recurrent cancers in the vagina. Lower doses to bladder and rectum were seen with ISBT plans. In half of the MCVC plans, the rectal dose met the recommended constraints. For plans in which the rectal constraint was not met, the target volumes were abutting the rectum and had a cranial-caudal length ≥ 5 cm. Dose to vaginal mucosa was lower in ISBT plans directed to the HRCTVs, although no difference was seen in circumferential IRCTVs. Conclusions Overall, ISBT results in decreased dose to OARs as compared to MCVC. However, MCVC BT results in acceptable doses to OARs with possible improvement in vaginal doses for circumferential targets. Careful consideration to tumor geometry and location may help guide optimal techniques in vaginal tumor brachytherapy.

Modern radiotherapy techniques enable delivery of high doses to the target volume without escalating dose to organs at risk, offering the possibility of better local control while preserving good quality of life. Uncertainties in target volume delineation have been demonstrated for most tumour sites, and various studies indicate that inconsistencies in target volume delineation may be larger than errors in all other steps of the treatment planning and delivery process. The aim of this paper is to summarize the degree of delineation uncertainties for different tumour sites reported in the literature and review the effect of strategies to minimize them.

BackgroundRadiotherapy is one of the main treatment methods for nasopharyngeal carcinoma (NPC). It requires exact delineation of the nasopharynx gross tumor volume (GTVnx), the metastatic lymph node gross tumor volume (GTVnd), the clinical target volume (CTV), and organs at risk in the planning computed tomography images. However, this task is time-consuming and operator dependent. In the present study, we developed an end-to-end deep deconvolutional neural network (DDNN) for segmentation of these targets.MethodsThe proposed DDNN is an end-to-end architecture enabling fast training and testing. It consists of two important components: an encoder network and a decoder network. The encoder network was used to extract the visual features of a medical image and the decoder network was used to recover the original resolution by deploying deconvolution. A total of 230 patients diagnosed with NPC stage I or stage II were included in this study. Data from 184 patients were chosen randomly as a training set to adjust the parameters of DDNN, and the remaining 46 patients were the test set to assess the performance of the model. The Dice similarity coefficient (DSC) was used to quantify the segmentation results of the GTVnx, GTVnd, and CTV. In addition, the performance of DDNN was compared with the VGG-16 model.ResultsThe proposed DDNN method outperformed the VGG-16 in all the segmentation. The mean DSC values of DDNN were 80.9% for GTVnx, 62.3% for the GTVnd, and 82.6% for CTV, whereas VGG-16 obtained 72.3, 33.7, and 73.7% for the DSC values, respectively.ConclusionDDNN can be used to segment the GTVnx and CTV accurately. The accuracy for the GTVnd segmentation was relatively low due to the considerable differences in its shape, volume, and location among patients. The accuracy is expected to increase with more training data and combination of MR images. In conclusion, DDNN has the potential to improve the consistency of contouring and streamline radiotherapy workflows, but careful human review and a considerable amount of editing will be required.