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Background and Objectives: Intensity-modulated radiation therapy (IMRT) is becoming a more common method of performing whole breast irradiation (WBI) for early breast cancer. This study aimed to examine the incidental dose to the axillary region using tomotherapy, a unique form of IMRT. Patients and Methods: This study included 30 patients with early-stage breast cancer who underwent adjuvant WBI using TomoDirect IMRT. A hypofractionation scheme of 42.4 Gy delivered in 16 fractions was prescribed. The plan comprised of two parallel-opposed beams, along with two additional beams positioned anteriorly at gantry angles of 20° and 40° from the medial beam. The incidental dose received at axillary levels I, II, and III was evaluated using several dose-volume parameters. Results: The study participants had a median age of 51 years, and 60% had left-sided breast cancer. The mean dose of the axilla for levels I, II, and III were 15.5 ± 4.8 Gy, 14.9 ± 4.2 Gy, and 1.5 ± 1.6 Gy, respectively. Adequate coverage of the axilla, defined as V95%[%], was achieved for 4.7 ± 3.9%, 4.8 ± 3.7%, and 0 ± 0% for levels I, II, and III, respectively. The results were compared with those of previously published studies, and the axillary mean dose and V95%[%] of TomoDirect IMRT were low, comparable to other IMRT techniques, and lower than those of traditional tangential therapy. Conclusions: While incidental axillary radiation during WBI has been proposed to assist in regional disease control, the TomoDirect plan was demonstrated to decrease this dose, and a hypofractionation scheme would further lower its biological effectiveness. Future clinical studies should incorporate dosimetrical analysis of incidental axillary dose, in order to facilitate hypofractionated IMRT planning with risk-adjusted axilla coverage in early breast cancer.

The present study aimed to reduce the parotid gland dose in the hippocampus avoidance with whole-brain radiotherapy (HA-WBRT) using the helical tomotherapy (HT). Ten patients who had previously undergone WBRT were randomly selected and enrolled in this study. During the treatment planning, two different techniques to the jaw were applied for each patient, namely, 1.0 cm fixed jaw and 2.5 cm dynamic jaw. To efficiently reduce the dose in the bilateral parotid glands, directional block (DB) mode was set. The DB is a function of a treatment planning system for the dose reduction in organs at risk. The standard HA-WBRT plan which did not reduce the parotid gland dose was also designed to compare the plan quality. Compared with the standard HA-WBRT plan, the parotid gland dose could be reduced by approximately 70% without extending the delivery time by adding the parotid gland on the DB mode to the dose constraint. In addition, the differences in dosimetric parameters observed between the plans employing the 1.0 cm fixed jaw and 2.5 cm dynamic jaw were almost negligible. Moreover, delivery time in the 2.5 cm dynamic jaw could be greatly reduced by 60% compared with that in the 1.0 cm fixed jaw.

Quantitative retrospective analysis of the normal lung irradiation due to the variations of the ITV volume based on the techniques used for upper lobe (UL), mid lobe (ML), and lower lobe (LL) lung tumours when used with 2-view, 1-view, 0-view based LOT technique on Cyberknife, AveIP on Helical Tomotherapy, and DIBH on VMAT systems. In the treatment of lung tumours, patients medically inoperable or those who are unwilling to undergo surgery have the option to be treated using radiation therapy. There are many motion control techniques available for the treatment of the moving target, such as movement encompassment, respiratory gating, breath-hold, motion reduction, and tumour monitoring. ITV generation is dependent on technique and hence the volume of the PTVs will differ based on the technique used. This study aimed to determine the influence of these ITVs on the irradiated normal lung volume for UL, ML, and LL lung tumours for 23 patients. The mean difference in the PTV volumes generated with the 0-view technique was significant with that of 2-view and DIBH techniques (p-value 0.11). In the treatment of lung tumour patients with SBRT, this study has demonstrated 2-view with Cyberknife and DIBH with VMAT treatment techniques have optimal normal lung tissue sparing. There was a significant increase in the average lung volume receiving 5%,10%, 20%, and 30% dose when comparing the 1-view, 0-view, AveIP, and DIBH techniques to the 2-view technique. However, DIBH with VMAT was dosimetrically advantageous for ML and LL tumours, while providing significantly shorter treatment times than any other technique studied.

As the use of hypofractionation has spread in the setting of curative prostate radiotherapy, few data are available in the post-operative scenario. This study reports a mono-institutional experience of moderate post-operative hypofractionated radiotherapy for prostate cancer. In February 2021, we retrospectively assessed the outcomes of 129 patients who received between April 2013 and May 2020 hypofractionated post-operative radiotherapy using Helical Tomotherapy. Toxicity was assessed using CTCAE criteria v4.0. Survival endpoints were calculated with Kaplan–Meier method. Median age and follow-up were, respectively, 67 years and 43 months. Adjuvant and salvage treatment were delivered to 63.5% and 36.4% of patients to a median total dose of 63.8 Gy (61.6–65.25 Gy) in 29 fractions (2.12–2.25 Gy/fraction). Pelvic lymph-nodes irradiation was performed in 67.4% of cases. ADT was added in 50%. Acute toxicity was: G1 and G2 GU events in 36% and 9.3% of cases; G1 and G2 GI events in 29.4% and 13.9%. Late GU toxicity occurred in 12.4% of cases: 3.1% G1, 7.7% G2 and 1.5% G3 events; GI toxicity consisted of 1.5% G1 and 7.7% G2 events. Biochemical relapse occurred in 26.3% of cases, recording no significant differences between adjuvant and salvage (p = 0.67), with 4- and 5-years bRFS rates of 78.7% and 75.6%. Two patients died of progressive disease and eight for non-oncological causes resulting in 3-years overall survival and cancer-specific survival rates of 98% and 98.4%. Our experience supports the use of moderate hypofractionation for prostate bed radiotherapy, with minimal toxicity and promising results in terms of clinical outcomes.

Xin Zhang,* Dingyi Yang,* Yong Jiang, Luo Huang, Can Wang, Dan Tao, Xianfeng Liu, Yongyang Lei, Yongzhong Wu, Wei Zhou Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yongzhong Wu; Wei ZhouChongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, 181 Han Yu Road, Chongqing, 400030, People’s Republic of ChinaTel +86 18323064006Email cqmdwyz@163.com; 1052308491@qq.comPurpose: We sought to compare the symptomatic radiation pneumonitis (RP) in lung cancer patients treated with helical tomotherapy (HT) versus intensity-modulated radiotherapy (IMRT), and examine the predictive value of circulating lymphocyte subsets affecting the occurrence of RP.Patients and Methods: Circulating lymphocyte subsets, clinical characteristics, dosimetric parameters and pulmonary function were collected from 130 lung cancer patients treated with HT (n = 53) or IMRT (n = 77) from 2016 through 2020. Symptomatic RP was compared between groups. Binary logistic regression was used to identify predictors of RP.Results: The IMRT group had larger planning target volume (319.9 vs 240.8 cc, P = 0.041); more ECOG performance status 0– 1 (96.1% vs 79.2%, P = 0.002); more stage III–IV disease (94.8% vs 37.6%, P = 0.028); and more combined systemic therapy (85.7% vs 69.8%, P = 0.022). Grade ≥ 2 RP were comparable between IMRT and HT groups (16.9% vs 15.1%, P = 0.785). For stage III–IV disease, IMRT was associated with lower lung V10 (31.9% vs 35.8%, P = 0.047) and lower incidence of grade 5 RP (0% vs 9.1%, P = 0.018). All lymphocyte subsets reduced after radiotherapy. The decrease degree of total T cell count and CD4+ T cell count were larger after IMRT than HT (P = 0.043, P = 0.021). In univariate analysis, the smoking status, lower baseline FEV1, and higher total T cell count, higher CD8+ T cell count, lower total B cell count, lower CD4+/CD8+ ratio after radiotherapy were associated with the development of grade ≥ 2 RP. The higher CD8+T cell count after radiotherapy was the only risk factor associated with grade ≥ 2 RP in multivariable analysis (OR 1.003; 95% CI: 1.000– 1.005; P = 0.044).Conclusion: IMRT was associated with lower lung V10 and less grade 5 RP than HT for stage III–IV lung cancer. Higher CD8+ T cell count after radiotherapy was associated with an increased risk of RP. HT may better preserve total T cell and CD4+ T cell than IMRT.Keywords: radiation pneumonitis, lung cancer, helical tomotherapy, intensity-modulated radiotherapy, circulating lymphocyte

Purpose Helical tomotherapy (HT) is a form of intensity‐modulated radiation therapy that is employed in total body irradiation (TBI). Because TBI targets the whole body, accurate setup positioning at the edge of the treatment volume is made difficult by the whole‐body rotational posture. The purpose of this study is to clarify the tolerance for rotational setup error (SE) in the vertical direction. In addition, we perform a retrospective analysis of actually irradiated dose distributions using previous patients’ irradiation data. Methods To clarify the effects of rotational SE on the dose distribution, the planned CT images of 10 patients were rotated by 1–5° in the vertical (pitch) direction to create a pseudo‐rotational SE image. Then, the effect of the magnitude of the rotational SE on the dose distribution was simulated. In addition, the irradiated dose to the patients was analyzed by obtaining recalculated dose distributions using megavoltage CT images acquired before treatment. Results The simulation results showed that the average value of the lung volume receiving at least 10 Gy did not exceed the allowable value when the SE value was ≤2°. When the rotational SE was ≤3°, it was possible to maintain the clinical target volume dose heterogeneity within ±10% of the prescribed dose, which is acceptable according to the guidelines. A retrospective analysis of previous patients’ irradiation data showed their daily irradiation dose distribution. The dose to the clinical target volume was reduced by up to 3.4% as a result of the residual rotational SE. Although whole‐course retrospective analyses showed a statistically significant increase in high‐dose areas, the increase was only approximately 1.0%. Conclusions Dose errors induced by rotational SEs of ≤2° were acceptable in this study.

Purpose Total skin electron beam therapy (TSEBT) is useful for primary cutaneous lymphoma. However, helical skin radiation therapy (HSRT) using tomotherapy may avoid the complexity and uncertainty of TSEBT. Methods and Materials All patients with primary cutaneous lymphoma who underwent HSRT at our hospital between June 2015 and July 2019 were investigated, including 7 patients registered in a clinical trial approved by an institutional review board (ID UMIN000022142). HSRT was performed in 3 partitioned skin areas: head and neck, trunk and arms, and legs. Results A total of 24 patients with 53 skin areas (including 8 patients with 24 skin areas who had undergone sequential total skin irradiation), with a median follow-up time of 13 months (range, 2-50), were investigated. Twenty patients (83.3%) had mycosis fungoides (MF). For 41 of 53 (77.4%) cases, a dose of 20 Gy in 10 fractions was used. The overall response rate in the treated fields of each HSRT in patients with MF was 100%, including 38 (80.9%) complete response, 4 (8.5%) good partial response, and 5 (10.6%) partial response. Eight patients with MF who underwent sequential total skin irradiation showed a 100% complete response. For patients with MF, the median survival time after a first round of HSRT was 22 months (95% confidence interval [CI], 13.6-30.4 months), the median response duration of each HSRT was 5 months (95% CI, 3.67-6.32 months), and the median time to in-field reirradiation for each HSRT was 15 months (95% CI, 9.76-20.24 months). Bone marrow suppression (grade ≥3) often occurred (94.1%) with HSRT on trunk and arm skin. An early patient died of HSRT-caused grade 5 leukopenia. Conclusions HSRT targeting trunk and arm skin induced severe bone marrow suppression that led to a temporary palliative effect. TSEBT should still be considered standard treatment for primary cutaneous lymphoma covering the total body surface area.

Total body irradiation (TBI) can be safely delivered on TomoTherapy (Accuray, Sunnyvale, CA, USA) in both pediatric and adult patients with proper imaging and planning despite the length constraint of 135 cm. To overcome this limitation, two CT (Computed Tomography) scans (CT1& CT2) are taken in patients above 135 cm in height. Adequate junction dose coverage is important in TBI. Presently, there is no clinical report with a focus on the quality of dose distribution at the CT junction in view of the guidelines on quality of coverage from the RTOG. Hence, our main objectives were to evaluate the dose distribution and quality of coverage at the junction in 16 patients who received TBI using TomoTherapy. PTV(upper) and PTV(lower) along with a junction were created on CT1 and CT2, respectively. Subsequently, the 10 cm junction in the thigh region was divided into five target volumes of 2 cm thickness with dose prescription ranging from 10 to 90% to deliver a total dose equal to 100% when fused. The D50 was equal to the prescribed dose in most of the cases ranging from 99.5 to 104% for PTV(upper), 100–103% for PTV(lower), and 99.5–108% for junctional PTVs (1PTV, 2PTV, 3PTV, 4PTV, and 5PTV). The average D95 doses from PTV(upper) and PTV(lower) were 97 ± 1.4% and 96.7 ± 1.08%, respectively. The average D95 doses for 1PTV, 2PTV, 3PTV, 4PTV, and 5PTV were 96.1 ± 1.88%, 91.6 ± 1.82%, 87.3 ± 1.5%, 91.6 ± 1.4%, and 96.2 ± 1.5% respectively. QRTOG values ranged between 0.85 and 1.05 and were in concordance with RTOG guidelines. Since junction-based planning was required for most TBI patients, it is essential to evaluate the quality of dose coverage in the junction for better TBI plans.

Objective The aim of the present study was to retrospectively evaluate the toxicity and efficacy of post-operative small pelvic intensity-modulated radiotherapy in early-stage cervical cancer patients with intermediate-risk factors. Methods Between 2012 and 2016, 151 patients who had cervical cancer (International Federation of Gynecology and Obstetrics stage I–IIA) with intermediate-risk factors were treated with post-operative small pelvic intensity-modulated radiotherapy. The median dose of 50.4 Gy in 28 fractions with small pelvic intensity-modulated radiotherapy was prescribed to the planning target volume. The intensity-modulated radiotherapy technique used was conventional fixed-field intensity-modulated radiotherapy or helical tomotherapy. Results The median follow-up was 37 months. The 3-year disease-free survival and overall survival rates were 89 and 96%, respectively. A total of 144 patients (95.3%) were alive at the last follow-up. In total, 6 patients (3.9%) had recurrence: locoregional recurrence in 3 patients (2%), distant metastasis in 2 (1.3%), and both in 1 (0.6%). Diarrhoea was the most common acute toxicity. There were no patients suffering from acute or late grade ≥ 3 toxicity. Only 4 patients (2.6%) had late grade 2 toxicities. Conclusions For early-stage cervical cancer patients with intermediate-risk factors, post-operative small pelvic intensity-modulated radiotherapy was safe and well tolerated. The rates of acute and late toxicities were quite satisfactory.

Purpose To evaluate dosimetric properties of intensity‐modulated proton therapy (IMPT) for simulated treatment planning in patients with atrial fibrillation (AF) targeting left atrial‐pulmonary vein junction (LA‐PVJ), in comparison with volumetric‐modulated arc therapy (VMAT) and helical tomotherapy (TOMO). Methods Ten thoracic 4D‐CT scans with respiratory motion and one with cardiac motion were used for the study. Ten respiratory 4D‐CTs were planned with VMAT, TOMO, and IMPT for simulated AF. Targets at the LA‐PVJ were defined as wide‐area circumferential ablation line. A single fraction of 25 Gy was prescribed to all plans. The interplay effects from cardiac motion were evaluated based on the cardiac 4D‐CT scan. Dose‐volume histograms (DVHs) of the ITV and normal tissues were compared. Statistical analysis was evaluated via one‐way Repeated‐Measures ANOVA and Friedman’s test with Bonferroni’s multiple comparisons test. Results The median volume of ITV was 8.72cc. All plans had adequate target coverage (V23.75Gy ≥ 99%). Compared with VMAT and TOMO, IMPT resulted in significantly lower dose of most normal tissues. For VMAT, TOMO, and IMPT plans, Dmean of the whole heart was 5.52 ± 0.90 Gy, 5.89 ± 0.78 Gy, and 3.01 ± 0.57 Gy (P

Purpose To verify clinical significance of submandibular gland (SMG)-sparing during helical tomotherapy (HT) for nasopharyngeal carcinoma (NPC) from the perspective of imaging by using diffusion weighted imaging (DWI). Materials and methods In this prospective study, 60 NPC patients scheduled for radical SMG-sparing HT were enrolled. All patients underwent DWI examinations prior to HT (pre-HT) and 1, 3, 6, 9, 12 months post HT. Mean apparent diffusion coefficient (ADC) values of bilateral parotid glands (PGs) and submandibular glands (SMGs) were measured. Differences of ADC and changes of ADC pre and pro HT (ΔADC) among SMG-spared, SMG-unspared and PGs were compared and the associations betweenΔADC and variations of patient-rated xerostomia questionnaire summary scores (XQ-sum) were further tested. Results ADCpost-HT and ΔADCpost-HT of SMG-spared were both much lower than of SMG-unspared and a strong dose–response relationship was detected between mean radiation dose and ΔADC of SMGs. Dynamic change trends of PGs, SMG-spared and SMG-unspared were similar, with initial increase at 1 m-post-HT followed by little change at 3 m-post-HT and then gradual decrease over time. But for SMG-unspared, there was no obvious change of ADC from 6 m-post-HT to 12 m-post-HT. The dynamic change trend of XQ-sum was nearly in line with that of ADC on the whole. And a positive correlation between mean ΔADC1m-post-HT of bilateral SMGs and variation of XQ-sum1m-post-HT in patients with bSMG-unspared were found (r = 0.693, P Conclusion SMG-sparing technique could significantly improve subjective xerostomia post HT in NPC patients from the perspective of imaging.

BACKGROUND: This dosimetric study on locally advanced pancreatic cancer (LAPC) and the surrounding gastrointestinal organs at risk (OARs) aimed at exploring the potential of further improving the internal dose and reducing the fractionation number by concurrent hypofractionated simultaneous integrated boost (SIB) radiotherapy using helical tomotherapy (HT). METHODS: We collected computed tomography positioning images from a LAPC study of 17 consecutive patients. Gross tumor volume (GTV)1, GTV2, and GTV3 were defined as the GTV minus a margin of 3, 6, and 9 mm from the external part in all directions, respectively. Under the same physical parameters and limited dose on normal organs, each case had 4 sets of SIB radiotherapy plans. Upon dose escalation, we statistically analyzed the difference of dosimetric parameters received by the OARs between group A [planning target volume (PTV)/GTV=50 Gy/70 Gy] and the other groups. According to the equivalent bioradiotherapy formula, we calculated the hypofractionated standard dose by converting the average tolerated dose of each OAR with the corresponding number of fractions. Then, we compared the dose and volume parameters of the gastrointestinal tract from the less-than-20-fraction modes with the corresponding gastrointestinal hypofractionated standard dose. RESULTS: For dose escalation, although there were a few differences in the parameters of the OAR between group A and group D, all OAR doses of group D (PTV/GTV/GTV1/GTV2/GTV3=50 Gy/70 Gy/80 Gy/90 Gy/100 Gy) were within the limited dose range. In the hypofractionated mode, there was a statistically significant difference between the gastrointestinal dose-volume parameters and the dose-limiting reference standard when the fraction number was less than 14 or 15 for group A or D, respectively. CONCLUSIONS: The dose of the internal target can be increased to 100 Gy with 15 fractions in the hypofractionated SIB radiotherapy for LAPC with HT. The corresponding tolerance dose of OARs may also be acceptable.

Along with surgery, radiation therapy (RT) remains an essential option to cure patients suffering from medulloblastoma. However, its long-term adverse effects, particularly due to craniospinal irradiation (CSI), which is necessary to eradicate microscopic spread, are a limiting factor. The most frequent sequelae involve neurocognitive and endocrine impairment, which occurs in nearly all patients. Recent progress achieved through genetic and molecular biology offers the possibility to better stratify patients according to risk factors such as age, post-resection tumour residue and metastasis. Thus, new therapeutic studies assess the possibility to reduce radiation dose and/or radiation field size for patients with the most favourable prognosis. New radiotherapy techniques are also used such as Intensity-Modulated Radiotherapy (IMRT), tomotherapy and proton therapy, which aim at reducing the dose delivered to normal tissue. Conventional photon-based therapy has a relatively high exit dose in contrast with proton therapy which causes less damage to surrounding healthy tissue. It is noteworthy that each technique requires a long follow-up in order to prove that late effects could be reduced without compromising survival rates. Dosimetric comparison theoretically suggests that proton therapy may be the superior method for CSI in terms of late effects, but further research is needed to firmly establish this. Whatever the technique used, the great complexity of CSI requires discipline and expertise along with an external quality control online before the first RT session.

To evaluate attenuation of the totally implantable vascular access device (TIVAD) and assess its clinical and dosimetric impact on radiotherapy (RT) of lymphoma patients.The first part of the study consisted of an in vitro approach by irradiating the TIVAD with different electron and photon energies. The attenuation data measured were compared with data calculated by our treatment planning system. All patients treated by radiotherapy for Hodgkin's lymphoma with their TIVAD in the target volume were then reviewed to assess the clinical outcome and dosimetric comparison using different plan metrics. All patients were treated by 3D conformal radiotherapy (3DCRT) or intensity-modulated radiotherapy delivered by Helical Tomotherapy (HT).Nineteen patients treated for stage I-III HL were studied. Seven patients were treated exclusively on the side of TIVAD and 12 were treated bilaterally. Median prescription dose was 30Gy. No significant clinical or dosimetric differences were observed between the side of the TIVAD and the contralateral side in patients treated bilaterally. HT resulted in a significantly higher conformity index (P0.0022) and a significantly lower healthy tissue coverage (P=0.0008) than 3DCRT. The observed attenuation was 79% for 6 MeV, 59% for 9 MeV, and 46% for 12 MeV for electrons and 9% for 4 MV, 8% for 6 MV, 5% for 10 MV and 15 MV and 3% for 20 MV for X photons.TIVADs induce significant beam attenuation when using electrons, which can be overcome by using high-energy photons or by creating an exclusion zone in when HT is used.

We aimed to compare prototype treatment plans for a new biology-guided radiotherapy (BgRT) machine in its intensity-modulated radiation therapy (IMRT) mode with those using existing IMRT delivery techniques in treatment of nasopharyngeal carcinoma (NPC). We retrospectively selected ten previous NPC patients treated in 33 fractions according to the NRG-HN001 treatment protocol. Three treatment plans were generated for each patient: a helical tomotherapy (HT) plan with a 2.5-cm jaw, a volumetric modulated arc therapy (VMAT) plan using 2 to 4 6-MV arc fields, and a prototype IMRT plan for a new BgRT system which uses a 6-MV photon beam on a ring gantry that rotates at 60 rotations per minute with a couch that moves in small incremental steps. Treatment plans were compared using dosimetric parameters to planning target volumes (PTVs) and organs at risk (OARs) as specified by the NRG-HN001 protocol. Plans for the three modalities had comparable dose coverage, mean dose, and dose heterogeneity to the primary PTV, while the prototype IMRT plans had greater dose heterogeneity to the non-primary PTVs, with the average homogeneity index ranging from 1.28 to 1.50 in the prototype plans. Six of all the 7 OAR mean dose parameters were lower with statistical significance in the prototype plans compared to the HT and VMAT plans with the other mean dose parameter being comparable, and all the 18 OAR maximum dose parameters were comparable or lower with statistical significance in the prototype plans. The average left and right parotid mean doses in the prototype plans were 10.5 Gy and 10.4 Gy lower than those in the HT plans, respectively, and were 5.1 Gy and 5.2 Gy lower than those in the VMAT plans, respectively. Compared to that with the HT and VMAT plans, the treatment time was longer with statistical significance with the prototype IMRT plans. Based on dosimetric comparison of ten NPC cases, the prototype IMRT plans achieved comparable or better critical organ sparing compared to the HT and VMAT plans for definitive NPC radiotherapy. However, there was higher dose heterogeneity to non-primary targets and longer estimated treatment time with the prototype plans.

Skin toxicity is a common adverse effect of breast radiotherapy. We investigated whether inverse-planned intensity-modulated radiotherapy (IMRT) would reduce the incidence of skin toxicity compared with forward field-in-field breast IMRT (FiF-IMRT) in early stage breast cancer.This phase III randomised controlled trial compared whole-breast irradiation with either FiF-IMRT or helical tomotherapy IMRT (HT-IMRT), with skin toxicity as the primary end point. Patients received 50 Gy in 25 fractions and were assessed to compare skin toxicity between treatment arms.In total, 177 patients were available for assessment and the median follow-up was 73.1 months. Inverse IMRT achieved more homogeneous coverage than FiF-IMRT; erythema and moist desquamation were higher with FiF-IMRT compared with HT-IMRT (61% versus 34%; P 0.001; 33% versus 11%; P 0.001, respectively). Multivariate analysis showed large breast volume, FiF-IMRT and chemotherapy were independent factors associated with worse acute toxicity. There was no difference between treatment arms in the incidence of late toxicities. The 5-year recurrence-free survival was 96.3% for both FiF-IMRT and HT-IMRT and the 5-year overall survival was 96.3% for FiF-IMRT and 97.4% for HT-IMRT.Our study showed significant reduction in acute skin toxicity using HT-IMRT compared with FiF-IMRT, without significant reduction in late skin toxicities. On the basis of these findings, inverse-planned IMRT could be used in routine practice for whole-breast irradiation with careful plan optimisation to achieve the required dose constraints for organs at risk.

Purpose/Aim: Forward planned intensity-modulated radiotherapy (forward IMRT) with breath-hold (BH) technique is considered optimal by most practitioners for treating left-sided breast cancer. Regional nodal irradiation including axilla and supraclavicular fossa (SCF) increases can increase dose-to-organs at risk (OAR) especially lung. This study was done to assess the potential of inverse planned IMRT (inverse IMRT) to achieve significant reduction in dose to OAR. Materials and Methods: Ten patients with left-sided breast cancer treated with Active Breath Co-ordinator BH technique were included in the study. Forward IMRT plans were generated in both BH and free breathing (FB) scans. Inverse IMRT plans were generated in FB scan using Tomotherapy-Direct and Tomotherapy-Helical techniques. Contouring was done as per the ESTRO consensus contouring guidelines. The dose prescribed was 40 Gy in 15 fractions. Statistical significance was tested using one-way ANOVA for parametric data and Kruskall–Wallis test for nonparametric data. Multiple comparison tests were done by using Bonferroni test. P

Craniospinal irradiation (CSI) is a complex radiation therapy technique that is used for patients, often children and teenagers/young adults, with tumors that have a propensity to spread throughout the central nervous system such as medulloblastoma. CSI is associated with important long‐term side effects, the risk of which may be affected by numerous factors including radiation modality and technique. Lack of standardization for a technique that is used even in larger radiation oncology departments only a few times each year may be one such factor and the current ad hoc manner of planning new CSI patients may be greatly improved by implementing a dose–volume histogram registry (DVHR) to use previous patient data to facilitate prospective constraint guidance for organs at risk. In this work, we implemented a DVHR and used it to provide standardized constraints for CSI planning. Mann–Whitney U tests and mean differences at 95% confidence intervals were used to compare two cohorts (pre‐ and post‐DVHR intervention) at specific dosimetric points to determine if observed improvements in standardization were statistically significant. Through this approach, we have shown that the implementation of dosimetric constraints based on DVHR‐derived data helped improve the standardization of pediatric CSI planning at our center. The DVHR also provided guidance for a change in CSI technique, helping to achieve practice standardization across TomoTherapy and IMRT.

Radiation therapy (RT) is used for the treatment of sacral chordoma, in combination with surgery or alone for unresected tumours, to improve local control (LC) and potentially overall survival (OS). The purpose of the present study was to evaluate efficacy and toxicity of proton therapy (PT), and/or intensity modulated radiation therapy (IMRT), particularly Tomotherapy, for sacral chordoma treatment.After a median follow-up of 46 months (range, 0-125 months), eight local relapses were observed, and seven patients developed distant metastasis (particularly bone and lung). The 2- and 5- year local relapse rates were 11.4% CI (0.65-22.2%) and 29% (10.5-47.4%), respectively. Over the follow-up period, ten patients died (24.4%). The estimated 2- and 5-year OS rates were 91.4% CI (82.5-100%) and 74.5% (59.4-93.5%), respectively. Fibrosis,RT remains essential to improve local control in sacral chordoma. The combination of proton and photon seems to improve organ at risk sparing, resulting in a decreased rate of reported late toxicities.

Background The incidence of angioimmunoblastic T-cell lymphoma is rare worldwide, and it has a poor prognosis. There is no proven or standard first-line therapy that works for the majority of patients with angioimmunoblastic T-cell lymphoma because of the rarity of this disease. The treatment and management are challenging for clinicians. Case presentation This report presents the diagnosis and treatment of a 65-year-old Chinese man who presented with cough and lymph node swellings in the left axillary region. The patient was diagnosed with angioimmunoblastic T-cell lymphoma. He underwent eight cycles of chemotherapy with CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin, prednisone) followed by TOMO radiotherapy (helical tomotherapy, a kind of radiotherapy for cancer treatment using spiral computed tomographic scanning). After treatment, the therapeutic effects were evaluated by magnetic resonance imaging and computed tomography about every 3 months. The patient recovered well with no sign of tumor recurrence and no obvious severe treatment-related adverse effects. Conclusion This treatment experience indicates an essential role for the combination of radiation therapy with CHOP, which may have a better prognosis than treatments without radiation therapy. But challenges warrant further validation in prospective studies.

Purpose This study aimed to reduce radiation doses to the tongue, a patient-specific semi-customized tongue immobilization device (SCTID) was developed using a 3D printer for helical tomotherapy (HT) of nasopharyngeal cancer (NPCa). Dosimetric characteristics and setup stability of the SCTID were compared with those of a standard mouthpiece (SMP).Materials and Methods For displacement and robust immobilization of the tongue, the SCTID consists of four parts: upper and lower tooth stoppers, tongue guider, tongue-tip position guide bar, and connectors. With the SCTID and SMP, two sets of planning computed tomography and HT plans were obtained for 10 NPCa patients. Dosimetric and geometric characteristics were compared. Position reproducibility of the tongue with SCTID was evaluated by comparing with planned dose and adaptive accumulated dose of the tongue and base of the tongue based on daily setup mega-voltage computed tomography.Results Using the SCTID, the tongue was effectively displaced from the planning target volume compared to the SMP. The median mucosa of the tongue (M-tongue) dose was significantly reduced (20.7 Gy vs. 27.8 Gy). The volumes of the M-tongue receiving a dose of 15 Gy, 30 Gy, and 45 Gy and the volumes of the mucosa of oral cavity and oropharynx (M-OC/OP) receiving a dose of 45 Gy and 60 Gy were significantly lower than using the SMP. No significant differences was observed between the planned dose and the accumulated adaptive dose in any dosimetric characteristics of the tongue and base of tongue.Conclusion SCTID can not only reduce the dose to the M-tongue and M-OC/OP dramatically, when compared to SMP, but also provide excellent reproducibility and easy visual verification.

Purpose To evaluate the dosimetric impact of four different radiotherapy techniques for a case of left-sided breast cancer with Internal Mammary lymph Nodes (IMN) involvement. Materials and methods To identify the best radiotherapy technique for this patient, four methods were compared: 3D Conformal Radiotherapy (3D-CRT), Volumetric Modulated Arc Therapy (VMAT), Tomotherapy (TOMO) and Intensity Modulated Proton Therapy (IMPT). Patient was treated using deep inspiration breath-hold (DIBH) technique. Prescribed dose was 40.05y in 15 fractions. Plan evaluation was performed on target coverage and dose to the organs-at-risk (OARs) using 3D-CRT as a baseline. Results TOMO has the most ideal Conformity Index (CI) at 1.139, followed by IMPT at 1.158, VMAT at 0.765, and 3D-CRT at 0.685. Using 3D-CRT as a baseline, VMAT, TOMO and IMPT all showed improved dose coverage. IMPT has the best dose coverage. TOMO has the most ideal homogeneity index (HI) and Conformity Number (CN). Mean heart dose (MHD) is lowest for IMPT at 0.55 Gy and highest for VMAT at 4.79 Gy. V20Gy of left lung is the lowest for IMPT at 11.11%, compared to 17.53% for TOMO, 18.19% for VMAT and 33.33% for 3D-CRT. V5Gy for the contralateral breast ranges from 0.01% in IMPT to 72.32% in TOMO. Conclusion 3D-CRT compromising target coverage but achieving good OAR sparing for the contralateral right breast, left lung and right lung. Overall, IMPT performed best in terms of target coverage and OAR-sparing. Protons delivered superior target dose coverage and sparing of normal structures for this patient. As dose value parameters are expected to correlate with acute and chronic toxicities, proton therapy should be given due consideration as the preferred technique for the treatment of left-sided breast cancers with IMN involvement. Further studies with more patients can be done to evaluate the effectiveness of proton therapy on acute and chronic toxicities.

Importance Irradiation treatment for pediatric patients with neuroblastoma represents a major challenge due to the pediatric dose limits for critical structures and the necessity of sufficient dose coverage of the clinical target volume for local control. Objective To investigate dosimetric differences between tomotherapy (TOMO) and volumetric‐modulated arc therapy (VMAT) as retroperitoneal radiotherapy for children with neuroblastoma. Methods Eight patients who received retroperitoneal radiotherapy for neuroblastoma were selected for comparison of TOMO and VMAT treatment plans. The Dmin, Dmax, Dmean, D95, D2, and D98 of planning target volume (PTV), conformity index (CI), heterogeneity index (HI), and organs at risk (OARs) parameters were compared. Delivery machine unit (MU) and image‐guide radiotherapy solution results were also compared. Results All patients received a cumulative dose of 19.5 Gy to the PTV. VMAT showed higher CI (0.93 ± 0.02), compared with TOMO (0.87 ± 0.03, P < 0.001). Notably, the average PTV HI was significantly better using TOMO (1.05 ± 0.01) than VMAT (1.08 ± 0.02, P = 0.003). Compared with VMAT, the Dmin, D95, and D98 all exhibited increases in TOMO; Dmax variation was less than 1% in TOMO. The D0.1cc for the spinal cord and D2cc for the small intestine were better in TOMO in terms of OARs. However, TOMO had more MUs and required a longer delivery time. Interpretation Both planning techniques are capable of producing high‐ quality treatment plans. TOMO is superior for PTV coverage, but inferior for CI. TOMO requires extra treatment time; its cost is greater than the cost of VMAT., Both tomotherapy (TOMO) and volumetric‐modulated arc therapy (VMAT) techniques are capable of producing high‐quality treatment plans for retroperitoneal radiotherapy for pediatric patients with neuroblastoma. In TOMO plan, The PTV HI, Dmin, D95%, D98%, Dmax, D0.1cc for the spinal cord, and D2cc for the small intestine was significantly better than that for VMAT. But the PTV CI, treatment time, medical cost of VMAT was better than that of TOMO.

BACKGROUND (I) Dosimetric comparison between Helical tomotherapy (HT) and intensity-modulated radiation therapy (IMRT) with hypofractionated simultaneously integrated boost (HF-SIB) technique for spine metastasis. (II) Mega-voltage CT (MVCT) imaging can be used to monitor changes and calculate the true spinal cord dose over multiple fractions, and compare it with the planned dose by deformable image registration. METHODS We retrospectively analyzed 57 patients with spine metastasis receiving HT at our institution between March 2016 and March 2019. (I) The dose/fraction to planning gross tumor volume (PGTV) and planning target volume (PTV) were 40 or 50 Gy/10 fractions and 30 or 40 Gy/10 fractions. Plans were compared according to PTV coverage and OARs sparing. (II) The daily MVCT were strictly registered with plan CT according to the rigid structures. Contours of the target and critical organs were then deformed from plan CT to MVCT using MIM deformable registration algorithm. After rigid imaging registration, the planning dose matrix was mapped to the MVCT images. The total doses of 10 fractions to the deformed structures were compared with the planned doses. RESULTS Comparing HT and IMRT plan averaged over all patients, differences were observed for both homogeneity index (HI) (P

Purpose. We assessed the clinical outcomes and toxicities following hypofractionation with helical tomographic intensity-modulated radiotherapy technology (tomotherapy) in patients with stage III non-small cell lung cancer (NSCLC) who were not candidates for surgery or concurrent chemoradiation. Methods. Forty-three patients with stage III NSCLC who were treated between 2011 and 2017 were enrolled. The prescription doses for gross target volume and clinical target volume were 70 Gy and 60 Gy (respectively) delivered in 15–25 fractions over 3–5 weeks. Results. The median overall survival (OS) time was 34.23 (range 11.33–99.33) months. The estimated 1-, 2-, and 3-year OS rates were 97.7%, 74.4%, and 55.9%, respectively; the corresponding progression-free survival (PFS) rates were 79.1%, 53.5%, and 36.1%, respectively. The local disease recurrence, regional disease recurrence, and distant metastasis rates at 3 years were 4.7%, 11.62%, and 55.81%, respectively. On multivariate analysis, dose regimen (p<0.05). Seven patients developed grade 1-2 acute radiation pneumonia (RP), 5 patients developed grade 1-2 late RP, while 3 patients developed grade 3 late RP. None of the patients developed grade 4-5 radiation lung injury. Conclusion. Tomotherapy may be an effective treatment option for patients with stage III NSCLC. It may be a viable alternative to surgery with lower incidence of side effects.

Major advances in external beam radiation therapy in the last decade have provided technologies for planning and delivering highly conformal radiation dose distributions made available by refined beam targeting methods, including intensity-modulated radiation therapy using tomotherapy, volumetric modulated arc therapy and many other auspicious tools for 3D dose painting. The emergence of magnetic resonance imaging (MRI) systems integrated with linear accelerators (linacs), commonly known as an MR-linacs, have realized MR-image guided radiation therapy (MRgRT) systems.

Aim:The purpose of the present study is to compare hybrid [three-dimensional conformal radiation therapy-volumetric-modulated arc therapy (3DCRT-VMAT)] and helical tomotherapy (HT) techniques in terms of both planning target volume (PTV) and organs at risk (OARs) in the plans we made in locally advanced non-small cell lung cancer (NSCLC) patientsMaterial and methods:Radiotherapy was planned for 15 locally advanced NSCLC patients with 2 different techniques. Large tumours with positive mediastinal lymph nodes were preferred. The prescription dose was determined as 60 Gy at 30 fractions.Results:Mean PTV volume was 602·5 cc (range: 265–1461). Mean total lung volume was 4264 cc (range: 1885–6803). Homogeneity index, Dmean, Dmax, D2 and V105 were found to be lower in HT, V100, total monitor units (MU) and total beam on time were found to be lower in the hybrid plan. Total lung Dmean was found to be 17 Gy in both techniques. V10 value was 42·85 in the hybrid plan and 48·67 in HT (p = 0·037). Heart Dmean was 14·5 Gy in the hybrid plan and 18·7 in HT (p < 0·001), and V30 values were 18·1 and 22·9, respectively (p = 0·009).Conclusion:Suitable dose coverage and OAR doses can be provided with both techniques. Especially the opposite lung, heart and oesophagus doses can be kept lower with the hybrid plan, and lower MU and shorter beam on time can be provided.

Metastasis-directed therapy (MDT) is an investigational treatment option in patients with oligorecurrent prostate cancer (PCa). The aim of this retrospective study is to report oncologic outcome and toxicity of elective nodal radiotherapy (ENRT) in PCa patients affected by pelvic nodal oligorecurrence. 41 consecutive patients were treated with salvage radiotherapy. At biochemical recurrence after primary treatment, oligorecurrent disease was detected by positron emission tomography (PET) in 94% of the patients. Image-guided intensity modulated radiation therapy (IMRT) was delivered using tomotherapy. 83% of the patients received androgen deprivation therapy (ADT) in combination with ENRT. Survival analysis was performed with Kaplan–Meier method, log-rank test was used to analyze associations between survival end-points and clinical parameters. Multivariate analysis was performed using Cox proportional hazards regression models. Toxicity was registered according to Common Terminology Criteria for Adverse Events (CTCAE) v4.0. The median at follow-up was 33.6 months. At 3 years, overall survival (OS), cancer-specific survival (CSS), and biochemical progression-free survival (b-PFS) were 89%, 92%, and 53%, respectively. At univariate analysis, all survival end-points were correlated with the number of positive pelvic lymph nodes at oligorecurrence (≤ 3 vs > 3). Biochemical-PFS was correlated with PSA (p = 0.034) and PSA doubling time (p = 0.004) at oligorecurrence. At multivariate analysis, no independent variable was statistically significant. No patient experienced grade ≥ 2 late toxicity after radiotherapy. The number of metastatic lymph nodes and PSA doubling time seems to be important prognostic factors in the pelvic oligorecurrent setting. Salvage radiotherapy combined with short-course ADT might be a valid treatment strategy.

Intensity-modulated radiotherapy with simultaneous integrated boost (IMRT-SIB) reduces overall treatment duration and results in less radiotherapy (RT)-induced dermatitis. However, the use of traditional sequential approach or IMRT-SIB is still under debate since there is not enough evidence of long-term clinical outcomes. The present study investigated 216 patients who underwent breast conserving surgery (BCS) between 2010 and 2013. The median age was 51 years (range, 21–81 years). All patients received IMRT-SIB, 50.4 Gy at 1.8 Gy per fraction to the whole breast and 60.2 Gy at 2.15 Gy per fraction to the tumor bed by integral boost. Among 216 patients, 175 patients received post-operative RT with forward IMRT and 41 patients had Tomotherapy. The median follow-up was 6.4 years. Forty patients (97.6%) in the Tomotherapy arm and 147 patients (84%) in the IMRT arm developed grade 0–1 skin toxicity (P = 0.021). For the entire cohort, the 5-year and 7-year overall survival (OS) rates were 94.4% and 93.1% respectively. The 7-year distant metastasis-free survival rates were 100% vs 89.1% in the Tomotherapy and IMRT arm respectively (P = 0.028). In conclusion, Tomotherapy improved acute skin toxicity compared with forward IMRT-SIB. Chronic skin complication was 1.9%. IMRT-SIB resulted in good long-term survival.

BACKGROUND Extended-field (EF) bone marrow-sparing (BMS) radiotherapy is attracting interest for cervical cancer patients with para-aortic lymphadenopathy. OBJECTIVE To compare dosimetric quality of volumetric-modulated arc therapy (VMAT) vs. helical tomotherapy (HT) during EF BMS radiotherapy. METHODS HT dose-volume histogram parameters including (1) coverage, homogeneity, and conformity of target volumes, (2) sparing of organs-at-risk, (3) monitor units, and (4) estimated treatment time were compared with those of VMAT in 20 cervical cancer patients who underwent EF BMS radiotherapy. The pelvic and para-aortic regions received 45-Gy dose (25 fractions), with simultaneous integrated boost of 55 Gy (25 fractions) for pelvic and para-aortic lymphadenopathy, followed by a parametrial boost of 9 Gy (5 fractions). RESULTS The HT-based and VMAT techniques achieved adequate and similar target volume coverage with good dose homogeneity and conformity, while sparing all organs-at-risk, including the rectum, bladder, bowel, bone marrow, femoral head, kidney, and spinal cord. The HT treatment plan had significantly higher monitor units (p

Background Both plan quality and robustness were investigated through comparing some dosimetric metrics between intensity modulated proton therapy (IMPT) and helical tomotherapy based intensity modulated radiotherapy (IMRT) for cervical cancer. Methods Both a spot-scanning robust (SRO) IMPT plan and a helical tomotherapy robust (TRO) IMRT plan were generated for each of 18 patients. In order to evaluate the quality of nominal plans without dose perturbations, planning scores (PS) on clinical target volume (CTV) and five organs at risk (OARs) based on clinical experience, and normal tissue complication probabilities (NTCP) of rectum and sigmoid were calculated based on Lyman-Kutcher-Burman (LKB) model. Dose volume histogram bands width (DVHBW) were calculated in 28 perturbed scenarios to evaluate plan robustness. Results Compared with TRO, the average scores of SRO nominal plans were higher in target metrics [V46.8Gy, V50Gy, Conformity and Homogeneity](16.5 vs. 15.1), and in OARs metrics (60.9 vs. 53.3), including bladder [V35,V45, Dmean,D2cc], rectum [V40,V45,D2cc,Dmax], bowel [V35,V40,V45, Dmax], sigmoid [V40,Dmax] and femoral heads [V30,Dmax]. Meanwhile, NTCP calculation showed that the toxicities of rectum and sigmoid in SRO were lower than those in TRO (rectum: 2.8% vs. 4.8%, p Conclusion Better CTV coverage and OAR Sparing were obtained in SRO nominal plan. Based on NTCP calculation, SRO was expected to allow a small reduction in rectal toxicity. Furthermore, SRO generated a more robust plan in CTV target coverage.

The dose received by the lungs in radiotherapy (RT) is affected by the patient’s current lung volume. The presence of predictive factors and cut-off points were investigated to achieve acceptable lung doses in esophageal cancer (EC) treatment. Virtual RT volumes of supracarinal EC were delineated. RT plans were designed with standard criteria in the TomoTherapy planning system (TomoTherapy Inc., Madison, WI, USA). The total dose was 50.4 Gy (1.8 Gy/fraction). ROC (Receiver operating characteristic) analysis and Mann–Whitney U tests were performed. There was a total of 65 patient plans included. ROC analysis showed that lung/PTV (Planning target volume) volume ratio (AUC [Area under curve]: 0.91, 95% CI: 0.83–0.99, p = 0.000) and bilateral lung volume (AUC: 0.81, 95% CI: 0.70–0.92, p = 0.000) have diagnostic power to predict the suitability of RT plans according to QUANTEC (Quantitative Analyses of Normal Tissue Effects in the Clinic) for lung dose constraints. The cut-off points of 7 and 3500 cc were selected for lung/PTV ratio and bilateral lung volume, respectively. The effect of the cut-off points on the dose data was assessed with the Mann–Whitney U test. The mean lung and heart doses, lung V5, V15, and V20, as well as heart V5, V20, V30, and V45 values were found to be lower in both groups separated by cut-off points (p

Background/aim This study aimed to evaluate the clinical outcome of intensity-modulated radiation therapy (IMRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) in uterine cervical cancer (UCC). IMRT consisted of whole-pelvic radiation therapy (WPRT) and sequential WPRT with central-shielding (WPRT-CS). Patients and methods Thirty UCC patients treated with IMRT using TomoTherapy, were retrospectively analyzed. Results The median dose of WPRT and WPRT-CS was 36 and 14.4 Gy and the median total dose of these was 50 Gy in 25 fractions (Fr). Median HDR-ICBT dose/Fr to Point A was 25 Gy/5 Fr. Median 2 Gy per fraction-equivalent dose (EQD2) of combined WPRT and HDR-ICBT to Point A (α/β=10) was 71.0 Gy. The 3-year local control, disease-free survival, and overall survival rates were 89.9%, 83.3%, and 86.3%. Conclusion IMRT of WPRT and WPRT-CS given in combination with HDR-ICBT was a feasible therapy resulting in good disease control and tolerance in patients with UCC.

Background: Postoperative irradiation for brain tumor in pregnant women is a matter of concern. Aim: We aimed to assess the safety of radiotherapy for brain tumors in pregnancy. We here report a successful treatment for anaplastic astrocytoma during pregnancy: surgery + postoperative irradiation. We wish to emphasize how we devised irradiation procedure to achieve both therapeutic effectiveness and safety to the fetus/infant. Case Presentation: A 34-year-old pregnant woman suffered with brain anaplastic astrocytoma. Tumor resection under craniotomy was performed with success. We decided to conduct postoperative radiotherapy at 25 weeks of gestation to reduce the risk of recurrence. We used a flattening filter-free volumetric arc therapy (FFF-VMAT) technique, which can achieve lower out-of-field dose than VMAT with a flattening filter or helical tomotherapy. We prescribed 60 Gy over 30 fractions. During actual beam delivery, surface and rectal dose to the patient (mother) were measured. The total fetal dose was estimated at 0.006 - 0.018 Gy, which is under the threshold set by the ICRP. A male healthy infant was born vaginally at the 37th week of pregnancy. The patient (mother) and the infant are healthy at the time of writing. Conclusion: FFF-VMAT is a good choice for brain tumors during pregnancy.

Nasopharyngeal carcinoma (NPC) patients treated with Helical Tomotherapy (HT) are commonly set up in an extended neck (EN) or a flexed neck (FN) position. This study investigated the dosimetric and set-up accuracy differences between these 2 set-up positions. Twenty NPC patients treated with HT from each set-up position were retrospectively recruited. HT plans were computed using the same target prescription and organs at risks (OARs) constraints for both set-up positions. The doses parameters of the target volumes and OARs were assessed. Daily megavoltage CT images were retrieved to obtain the set-up errors at 4th (C4) and 7th (C7) cervical levels. The mean values of these parameters were compared between the 2 set-up positions. The dose to NP target in FN group was more conformal than EN group, while the conformity of the neck targets in FN group were significantly lower. For the OARs, the temporal lobe, cerebellum, and hippocampus in FN group received significantly lower doses than the EN. However, the optic structures, brain stem, spinal cord, and parotid glands received higher doses in FN group. The systematic errors at C4 and C7 levels in FN group were larger in all translational directions except the ML direction at C7 level. With regard to radiotherapy of NPC patient using helical tomotherapy, FN position reduced doses to intracranial structures but increased doses to optic structures and other structures when compared with the EN position. In terms of set-up accuracy at the neck region, EN position was relatively better.

To compare the dosimetric characteristics of helical tomotherapy (HT), volumetric-modulated arc therapy (VMAT), intensity-modulated radiotherapy (IMRT), and tangential field-in-field technique (FIF) for the treatment of synchronous bilateral breast cancer (SBBC).Ten patients with early-stage unilateral breast cancer were selected for simulating the patients with SBBC in this retrospective analysis. Treatment plans with HT, VMAT, IMRT, and FIF were generated for each patient with a total dose of 50.4 Gy in 28 fractions to the target. Plan quality, namely conformity index (CI), homogeneity index (HI), dose-volume statistics of organs at risk (OARs), and beam-on time (BOT), were evaluated.HT plans showed a lower mean heart dose (3.53 ± 0.31Gy) compared with the other plans (VMAT = 5.6 ± 1.36 Gy, IMRT = 3.80 ± 0.76 Gy, and FIF = 4.84 ± 2.13 Gy). Moreover, HT plans showed a significantly lower mean lung dose (p0.01) compared with the other plans: mean right lung doses were 6.81 ± 0.67, 10.32 ± 1.04, 9.07 ± 1.21, and 10.03 ± 1.22 Gy and mean left lung doses were 6.33 ± 0.87, 8.82 ± 0.91, 7.84 ± 1.07, and 8.64 ± 0.99 Gy for HT, VMAT, IMRT, and FIF plans, respectively. The mean dose to the left anterior descending artery was significantly lower in HT plans (p0.01) than in the other plans: HT = 19.41 ± 0.51 Gy, VMAT = 25.77 ± 7.23 Gy, IMRT = 27.87 ± 6.48 Gy, and FIF = 30.95 ± 10.17 Gy. FIF plans showed a worse CI and HI compared with the other plans. VMAT plans showed shorter BOT (average, 3.9 ± 0.2 minutes) than did HT (average, 11.0 ± 3.0 minutes), IMRT (average, 6.1 ± 0.5 minutes), and FIF (average, 4.6 ± 0.7 minutes) plans.In a dosimetric comparison for SBBC, HT provided the most favorable dose sparing of OARs. However, HT with longer BOT may increase patient discomfort and treatment uncertainty. VMAT enabled shorter BOT with acceptable doses to OARs and had a better CI than did FIF and IMRT.

Highlights • An optimal and safe irradiation method for pregnant woman remains controversial. • Flattening-filter free VMAT could reduce the fetal exposure significantly. • As adjuvant CCRT, 66 Gy to the involved nodes was delivered over 33 fractions. • Without any shielding device, the fetal dose of 0.03 Gy in total was estimated. • A vigorous liveborn girl was born vaginally and she had no complications until now., Optimizing irradiation protocols for pregnant women is challenging, because there are few cases and a dearth of fetal dosimetry data. We cared for a 36-year-old pregnant woman with tongue cancer. Prior to treatment, we compared three intensity-modulated radiation therapy (IMRT) techniques, including helical tomotherapy, volumetric arc therapy (VMAT), and flattening-filter free VMAT (FFF-VMAT) using treatment planning software. FFF-VMAT achieved the minimum fetal exposure and was selected as the optimal modality. We prescribed 66 Gy to the involved nodes, 60 Gy to the tumor bed and ipsilateral neck, and 54 Gy to the contralateral neck over 33 fractions. To confirm the out-of-field exposure per fraction, surface doses and the rectal dose were measured during FFF-VMAT delivery. Postoperative chemoradiotherapy was delivered using IMRT and a cisplatin regimen. Without any shielding, the total fetal dose was 0.03 Gy, within the limits established by the ICRP. A healthy girl was born vaginally at 37 weeks’ gestation.

This study presents the experience of one center in the development and implementation of two different methods of totalbody irradiation (ТОТ) based on radiation therapy with intensity modulation, namely, Helical TomoTherapy (HT) and Volumetric Modulated Arc Therapy (VMAT), implemented on the classic linear accelerator Elekta Synergy. The aim of the work is the comparison of two TBI methods, as well as a description of the process of introducing these methods into the routine practice of the radiotherapy department. The study was approved by the Independent Ethics Committee of the Dmitry Rogachev Nationa Medical Research Center of Pediatric Hematology, Oncology and Immunology. Prescribed total doses: PTV – 12.0 Gy with a single fraction of 2.0 Gy twice per a day, at least 95% of PTV should have received a dose of 11.4 Gy, the volume of each lung receiving 8.0 Gy should not exceed 40%, the average dose in each of the kidneys should not exceed 9.0 Gy, the dose in the anterior segment of the eye should be reduced as much as possible while maintaining the dose in surrounding part of PTV. In total, from July 2014 to December 2018, 156 patients received TBI, 128 of which on TomoTherapy and 28 on Elekta. The use of a standardized approach to TBI from July 2015 to December 2018 made it possible to introduce TBI into the routine practice of the radiotherapy department. A standardized approach to TBI was implemented with the irradiation of 17 on Elekta and 91 on TomoTherapy. It allowed us toobtain uniform reproducible results in terms of dosimetric criteria. The volume of lungs receiving a dose of 8.0 Gy did not exceed 40% for TomoTherapy and for Elekta, the average dose in the kidneys did not exceed 8.0 Gy for both modalities. In the standardized versions of TBI, 10.0 Gy cover at least 95% of the ribs volume, in accordance with the prescription. In both cases, the quality of PTV coverage met the prescribed criteria, namely, at least 95 percent of the volume of PTV received at least 95% of the prescribed dose (11.4 Gy). The minimum dose in the lungs was 6.2 ± 0.2 Gy and 5.1 ± 0.4 Gy, for TomoTherapy and Elekta respectively. The presence or absence of the clinical significance of this criterion is to be assessed. The developed TBI methods allow to deliver the prescribed dose to the target while maintaining the specified dose levels in the organs at risk. However, TomoTherapy plans have better target coverage and homogeneity than VMAT-based plans for Elekta. The use of a standardized approach makes it possible to quantify treatment plans for these techniques.

Purpose To investigate the differences in treatment outcomes between two radiation techniques, intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT). Materials and methods We retrospectively analyzed 160 (IMRT = 23, 3DCRT = 137) patients with stage I glottic cancer treated from January 2005 through December 2016. The IMRT was performed with TomoTherapy (16 patients), volumetric-modulated arc therapy (6 patients), and step-and-shoot technique (1 patient), respectively. The 3DCRT was performed with bilateral parallel opposing fields. The median follow-up duration was 30 months (range, 31 to 42 months) in the IMRT group and 65 months (range, 20 to 143 months) in the 3DCRT group. Results The 5-year overall survival and 3-year local control rates of the 160 patients were 95.7% and 91.4%, respectively. There was no significant difference in 3-year local control rates between the IMRT and 3DCRT groups (94.4% vs. 91.0%; p = 0.587). Thirteen of 137 patients in the 3DCRT group had recurrences. In the IMRT group, one patient had a recurrence at the true vocal cord. Patients treated with IMRT had less grade 2 skin reaction than the 3DCRT group, but this had no statistical significance (4.3% vs. 21.2%; p = 0.080). Conclusion IMRT had comparable outcomes with 3DCRT, and a trend of less acute skin reaction in stage I glottic cancer patients.

To evaluate treatment outcomes for patients with localized prostate cancer who were treated with dose-escalated primary image-guided radiation therapy (IGRT). We retrospectively analyzed 88 consecutive patients treated using helical tomotherapy with daily megavoltage CTs (MVCT). Patients were prescribed daily doses of 1.8 Gy to the planning target volume (PTV) and 2 Gy to the clinical target volume (CTV). Low- and favorable intermediate-risk patients received a minimum total dose of 72 Gy to the PTV and up to 80 Gy to the CTV. Unfavorable intermediate-risk and high-risk patients received a minimum total dose of 75.6 Gy to the PTV and up to 84 Gy to the CTV. We assessed freedom from biochemical relapse (FFBF), 5‑year biochemical recurrence-free survival (5-bRFS), distant metastasis-free survival (5-dMFS), and cancer-specific survival (5-CSS) as well as acute and late genitourinary (GU) and gastrointestinal (GI) toxicity. Among our cohort, 11.4% were low-risk, 50% intermediate-risk, and 38.6% high-risk patients according to the D’Amico criteria. Median follow-up was 66 months (range 8–83 months). FFBF was 100%, 97.7%, and 90.7%; 5‑bRFS was 100%, 92.8%, and 70.4%; 5‑dMFS was 100%, 92.7%, and 70.4%; and 5‑CSS was 100%, 97.4%, and 89.8% for low-, intermediate-, and high-risk patients, respectively. Grades 2 and 3 toxicity occurred at the following rates: acute GU toxicity 39.8% and 1.1%, acute GI toxicity 12.5% and 0%, late GU toxicity 19.3% and 4.5%, and late GI toxicity 4.5% and 1.1% of patients, respectively. No toxicity >grade 3 was observed. Risk-adapted dose-escalated IGRT with helical tomotherapy of up to 84 Gy is a feasible and well-tolerable treatment scheme with promising oncological results.