scholarly journals The new SRS/FSRT technique HyperArc for benign brain lesions: a dosimetric analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hsiu-Wen Ho ◽  
Ching-Chieh Yang ◽  
Hsiu-Man Lin ◽  
Hsiao-Yun Chen ◽  
Chun-Chiao Huang ◽  
...  
Keyword(s):  
Organs At Risk ◽  
Treatment Plan ◽  
Brain Lesion ◽  
Brain Lesions ◽  
Conformity Index ◽  
Treatment Plans ◽  
The Mean ◽  
Dosimetric Analysis ◽  
Almost All ◽  
The Brain

AbstractTo evaluate the potential benefit of HyperArc (HA) fractionated stereotactic radiotherapy (FSRT) for the benign brain lesion. Sixteen patients with a single deep-seated, centrally located benign brain lesion treated by CyberKnife (CK, G4 cone-based model) were enrolled. Treatment plans for HA with two different optimization algorithms (SRS NTO and ALDO) and coplanar RapidArc (RA) were generated for each patient to meet the corresponding treatment plan criteria. These four FSRT treatment plans were divided into two groups—the homogeneous delivery group (HA-SRS NTO and coplanar RA) and the inhomogeneous delivery group (HA-ALDO and cone-based CK)—to compare for dosimetric outcomes. For homogeneous delivery, the brain V5, V12, and V24 and the mean brainstem dose were significantly lower with the HA-SRS NTO plans than with the coplanar RA plans. The conformity index, high and intermediate dose spillage, and gradient radius were significantly better with the HA-SRS NTO plans than with the coplanar RA plans. For inhomogeneous delivery, the HA-ALDO exhibited superior PTV coverage levels to the cone-based CK plans. Almost all the doses delivered to organs at risk and dose distribution metrics were significantly better with the HA-ALDO plans than with the cone-based CK plans. Good dosimetric distribution makes HA an attractive FSRT technique for the treatment of benign brain lesions.

scholarly journals Differential Dose Distribution in Transition from 3-D CRT to IMRT Treatment Plans for Glioblastoma Multiforme' at Stage III or IV: A Clinical Study of a Brain Tumor

2018 ◽  
Vol 19 (1) ◽  
pp. 64
Author(s):  
Sadiq R Malik ◽  
Shohel Reza ◽  
MM Shakhawat Hossain
Keyword(s):  
Radiation Therapy ◽  
Dose Distribution ◽  
Selection Process ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Target Volume ◽  
Conformity Index ◽  
Tumor Control ◽  
Treatment Plans

<p><span>Advancement in Cancer Therapy Technology (CTT) due to Software, Hardware and precise delivery of radiation dose has enhanced the quality of life of cancer patients. This report aims at the application of 3-D CRT (Three Dimensional Conformal Radiation Therapy) and IMRT (Intensity Modulated Radiation Therapy) for a quality of treatment. Other anatomical sites viz. Prostate, Lung, etc. may also be treated provided a better tool is applied for target delineation for which FUSION of CT and MRI images are used to ascertain differences in tissue density. This Fusion image of 3 mm slices offer accurate contouring of the tumor. The oncologist and/or physicist perform delineation of (I) GTV (Gross Tumor Volume), (II) CTV (Clinical Target Volume), (III) PTV (Planning Target Volume), (IV) TV (Treated Volume) and (V) OARs (Organs at Risk). This is done to secure conformal dose distribution and justify the clinical objectives of Tumor Control Probability (TCP) by reducing the normal tissue complication probability (NTCP). <span> </span><span> </span>The implication of this study outlines the fundamental goal of effective treatment procedures by comparing treatment plans of 3-D CRT and IMRT. Tolerance levels of dose to different organs are optimized by the analysis of random and systemic geometrical deviations, margin on target volumes, conformity index (CI), patient selection process and, of course, the shape and stage of target. The comparative parameters of treatment plans are segmented and tabulated to implicate the application of necessary tools to decide on a treatment plan for similar patients.</span></p><p><span>Bangladesh J. Nuclear Med. 19(1): 64-67, January 2016</span></p>

scholarly journals Patient-related QA for helical TomoTherapy with Delta4: analysis of the results

2017 ◽  
Vol 3 (2) ◽  
pp. 635-638 ◽  
Author(s):  
Henning Salz ◽  
Simon Howitz ◽  
Tim Brachwitz ◽  
Tilo Wiezorek
Keyword(s):  
Standard Deviation ◽  
Helical Tomotherapy ◽  
Treatment Plan ◽  
Measurement Procedure ◽  
Separate Analysis ◽  
Gamma Analysis ◽  
Treatment Plans ◽  
Cross Calibration ◽  
Almost All ◽  
Chamber Measurements

AbstractThe biplanar diode arrays Delta4PT and Delta4+ has been used in our hospital since the introduction of the TomoTherapy in 2013 to ensure a good agreement between the calculated and the measured dose distributions in patient-related QA with helical TomoTherapy. The aim of this presentation is to evaluate the quality of the measurement procedure with the Delta4 phantoms Delta4PT and (since January 2016) Delta4+. This includes the influence of a cross calibration with a treatment plan with low modulation.Two analyses were performed: (i) All treatment plans in a period of three months (n=86) were not only calculated and measured with Delta4PT or Delta4+ but also with an ionization chamber (Exradin A1SL) in the homogeneous “cheese phantom”. (ii) All data measured from January 2016 to April 2017 (Delta4+, n=132) were analyzed regarding median dose deviation, Gamma analysis and others.The comparison with chamber measurements shows that all measurements with Delta4 and almost all with the ionization chambers (79 of 86) yield a deviation of measured vs. planned dose in the PTV of less than 2.5%, but with a lower variation of the Delta4 measurements. However, a strong correlation between both was not observed.The separate analysis of the measurements with the newer Delta4+ (since January 2016) shows a mean dose deviation in the PTVs of only 0.14% with a standard deviation (S.D.) of 0.69%. Before every measurement a cross calibration has been performed. Without this cross calibration, the deviation would be 0.96% with an increased standard deviation of 0.93%.It is concluded that the Delta4 systems are well suited for patient-related QA for helical TomoTherapy treatment plans. The comparison with chamber measurements shows a plausible accordance between both systems whereas the variation of single measurements is quite different.With the help of a daily cross calibration the variability of the Delta4 results is further decreased and the results show higher accuracy and reliability. According to our experience, a daily cross calibration is mandatory for a reliable patient-related QA.

Dosimetric evaluation of whole-pelvis radiation therapy of prostate cancers: clinical experience

2020 ◽  
pp. 1-15
Author(s):  
Ernest Osei ◽  
Hafsa Mansoor ◽  
Johnson Darko ◽  
Beverley Osei ◽  
Katrina Fleming ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Radiation Therapy ◽  
High Risk ◽  
Cancer Patients ◽  
Seminal Vesicles ◽  
Conformity Index ◽  
Prostate Bed ◽  
Risk Patients ◽  
Treatment Plans ◽  
The Mean

Abstract Background: The standard treatment modalities for prostate cancer include surgery, chemotherapy, hormonal therapy and radiation therapy or any combination depending on the stage of the tumour. Radiation therapy is a common and effective treatment modality for low-intermediate-risk patients with localised prostate cancer, to treat the intact prostate and seminal vesicles or prostate bed post prostatectomy. However, for high-risk patients with lymph node involvement, treatment with radiation will usually include treatment of the whole pelvis to cover the prostate and seminal vesicles or prostate bed and the pelvic lymph nodes followed by a boost delivery dose to the prostate and seminal vesicles or prostate bed. Materials and Methods: We retrospectively analysed the treatment plans for 179 prostate cancer patients treated at the cancer centre with the volumetric-modulated arc therapy (VMAT) technique via RapidArc using 6 MV photon beam. Patients were either treated with a total prescription dose of 78 Gy in 39 fractions for patients with intact prostate or 66 Gy in 33 fractions for post prostatectomy patients. Results: There were 114 (64%) patients treated with 78 Gy/39 and 65 (36%) treated with 66 Gy/34. The mean homogeneity index (HI), conformity index (CI) and uniformity index (UI) for the PTV-primary of patients treated with 78 Gy are 0.06 ± 0.01, 1.04 ± 0.01 and 0.99 ± 0.01, respectively, and the corresponding mean values for patients treated with 66 Gy are 0.06 ± 0.02, 1.05 ± 0.01 and 0.99 ± 0.01, respectively. The mean PTV-primary V95%, V100% and V105% are 99.5 ± 0.5%, 78.8 ± 12.2% and 0.1 ± 0.5%, respectively, for patients treated with 78 Gy and 99.3 ± 0.9%, 78.1 ± 10.6% and 0.1 ± 0.4%, respectively, for patients treated with 66 Gy. The rectal V50Gy, V65Gy, V66.6Gy, V70Gy, V75Gy and V80Gy are 26.8 ± 9.1%, 14.2 ± 5.3%, 13.1 ± 5.0%, 10.8 ± 4.3%, 6.9 ± 3.1% and 0.1 ± 0.1%, respectively, for patients treated with 78 Gy and 33.7 ± 8.4%, 14.1 ± 4.5%, 6.7 ± 4.5%, 0.0 ± 0.2%, 0.0% and 0.0%, respectively, for patients treated with 66 Gy. Conclusion: The use of VMAT technique for radiation therapy of high-risk prostate cancer patients is an efficient and reliable method for achieving superior dose conformity, uniformity and homogeneity to the PTV and minimal doses to the organs at risk. Results from this study provide the basis for the development and implementation of consistent treatment criteria in radiotherapy programs, have the potential to establish an evaluation process to define a consistent, standardised and transparent treatment path for all patients that reduces significant variations in the acceptability of treatment plans and potentially improve patient standard of care.

scholarly journals Dosimetric and radiobiological comparison of treatment plan between CyberKnife and EDGE in stereotactic body radiotherapy for pancreatic cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhi-tao Dai ◽  
Li Ma ◽  
Ting-ting Cao ◽  
Lian Zhu ◽  
Man Zhao ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Spinal Cord ◽  
Stereotactic Body Radiotherapy ◽  
Dose Distribution ◽  
Normal Tissue ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Locally Advanced ◽  
Conformity Index ◽  
Homogeneous Dose

AbstractTo perform a comparison of the different stereotactic body radiotherapy (SBRT) plans between the Varian EDGE and CyberKnife (CK) systems for locally advanced unresectable pancreatic cancer. Fifteen patients with pancreatic cancer were selected in this study. The median planning target volume (PTV) was 28.688 cm3 (5.736–49.246 cm3). The SBRT plans for the EDGE and CK were generated in the Eclipse and Multiplan systems respectively with the same contouring and dose constrains for PTV and organs at risk (OARs). Dose distributions in PTV were evaluated in terms of coverage, conformity index (CI), new conformity index (nCI), homogeneity index (HI), and gradient index (GI). OARs, including spinal cord, bowel, stomach, duodenum and kidneys were statistically evaluated by different dose-volume metrics and equivalent uniform dose (EUD). The volume covered by the different isodose lines (ISDL) ranging from 10 to 100% for normal tissue were also analyzed. All SBRT plans for EDGE and CK met the dose constraints for PTV and OARs. For the PTV, the dosimetric metrics in EDGE plans were lower than that in CK, except that D99 and GI were slightly higher. The EDGE plans with lower CI, nCI and HI were superior to generate more conformal and homogeneous dose distribution for PTV. For the normal tissue, the CK plans were better at OARs sparing. The radiobiological indices EUD of spinal cord, duodenum, stomach, and kidneys were lower for CK plans, except that liver were higher. The volumes of normal tissue covered by medium ISDLs (with range of 20–70%) were lower for CK plans while that covered by high and low ISDLs were lower for EDGE plans. This study indicated that both EDGE and CK generated equivalent plan quality, and both systems can be considered as beneficial techniques for SBRT of pancreatic cancer. EDGE plans offered more conformal and homogeneous dose distribution for PTV, while the CK plans could minimize the exposure of OARs.

scholarly journals Fast oscillation dynamics during hypsarrhythmia as a localization biomarker

2018 ◽  
Vol 119 (2) ◽  
pp. 679-687 ◽  
Author(s):  
Min-Jee Kim ◽  
Mi-Sun Yum ◽  
Hye-Ryun Yeh ◽  
Tae-Sung Ko
Keyword(s):  
Brain Lesions ◽  
West Syndrome ◽  
Fast Oscillation ◽  
Pathologic Lesions ◽  
The Mean ◽  
Oscillation Dynamics ◽  
Fast Oscillations ◽  
Spectral Perturbation ◽  
The Brain ◽  
Eeg Pattern

Hypsarrhythmia in West syndrome, although hard to define, is characterized by chaotic and disorganized electrical activity of the brain and is often regarded as a generalized EEG pattern without any localization value. Using event-related spectral perturbation (ERSP), we tried to determine the brain dynamics during hypsarrhythmia. Routine 1-h scalp EEGs were retrieved from 31 patients with infantile spasms and 20 age-matched controls. Using the EEGLAB toolbox of MATLAB 2015b, the ERSPs of fast oscillations (FOs; 20–100 Hz) of selected channels were analyzed and compared among groups according to their MRI lesions. FO-ERSP cutoff values for predicting the pathologic foci were estimated. The mean FO-ERSPs across all analyzed electrodes of patients with spasms were significantly higher than those of controls. When the patients were categorized into nonlesional, focal/multifocal, or diffuse lesional groups, the FO-ERSP of patients in the focal/multifocal lesional group was significantly lower than that of those in the nonfocal or diffuse lesional groups. In the focal/multifocal lesional group, seven patients (7/9, 77.8%) showed that the locations of channels with high FO-ERSPs were matched to the pathologic MRI lesions. Thus, the localization of high FO-ERSPs is closely associated with the location of pathologic brain lesions. Further research is required to prove the value of the FO-ERSP as an important quantitative localizing biomarker of West syndrome. NEW & NOTEWORTHY The locations of high fast oscillation-event-related spectral perturbations (FO-ERSPs) are closely associated with brain pathologic lesions, and high FO-ERSPs can be used as a localization biomarker of pathologic brain lesions in patients with hypsarrhythmia. With further validation, FO-ERSP might be useful as a biomarker for the localization of hidden pathologies in conditions with generalized epileptiform activities such as West syndrome.

scholarly journals Aino Virus Antigen in Brain Lesions of a Naturally Aborted Bovine Fetus

1998 ◽  
Vol 35 (5) ◽  
pp. 409-411 ◽  
Author(s):  
Y. Noda ◽  
Y. Uchinuno ◽  
H. Shirakawa ◽  
S. Nagasue ◽  
N. Nagano ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Cerebrospinal Fluid ◽  
Nervous System ◽  
Brain Lesion ◽  
Neutralizing Antibody ◽  
Virus Antigen ◽  
Brain Lesions ◽  
Significant Feature ◽  
The Central Nervous System ◽  
The Brain

A bovine fetus aborted at 187 days of gestation was serologically and immunohistopathologically examined. Serum and cerebrospinal fluid samples had high titers of virus-neutralizing antibody for Aino virus. A severe necrotizing encephalopathy was noted. Aino virus antigen was demonstrated in neuroglial cells within the brain lesion. The destruction of developing neuronal cells appeared to be a significant feature of the pathogenesis of lesions due to Aino virus infection in the central nervous system.

scholarly journals Dosimetric Comparison of Upfront Boosting With Stereotactic Radiosurgery Versus Intraoperative Radiotherapy for Glioblastoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Gustavo R. Sarria ◽  
Zuzanna Smalec ◽  
Thomas Muedder ◽  
Jasmin A. Holz ◽  
Davide Scafa ◽  
...  
Keyword(s):  
Stereotactic Radiosurgery ◽  
Organs At Risk ◽  
External Beam Radiotherapy ◽  
Intraoperative Radiotherapy ◽  
Target Volume ◽  
Maximum Diameter ◽  
Target Definition ◽  
Treatment Plans ◽  
Previously Treated Patients ◽  
The Mean

PurposeTo simulate and analyze the dosimetric differences of intraoperative radiotherapy (IORT) or pre-operative single-fraction stereotactic radiosurgery (SRS) in addition to post-operative external beam radiotherapy (EBRT) in Glioblastoma (GB).MethodsImaging series of previously treated patients with adjuvant radiochemotherapy were analyzed. For SRS target definition, pre-operative MRIs were co-registered to planning CT scans and a pre-operative T1-weighted gross target volume (GTV) plus a 2-mm planning target volume (PTV) were created. For IORT, a modified (m)GTV was expanded from the pre-operative volume, in order to mimic a round cavity as during IORT. Dose prescription was 20 Gy, homogeneously planned for SRS and calculated at the surface for IORT, to cover 99% and 90% of the volumes, respectively. For tumors &gt; 2cm in maximum diameter, a 15 Gy dose was prescribed. Plan assessment was performed after calculating the 2-Gy equivalent doses (EQD2) for both boost modalities and including them into the EBRT plan. Main points of interest encompass differences in target coverage, brain volume receiving 12 Gy or more (V12), and doses to various organs-at-risk (OARs).ResultsSeventeen pre-delivered treatment plans were included in the study. The mean GTV was 21.72 cm3 (SD ± 19.36) and mGTV 29.64 cm3 (SD ± 25.64). The mean EBRT and SRS PTV were 254.09 (SD ± 80.0) and 36.20 cm3 (SD ± 31.48), respectively. Eight SRS plans were calculated to 15 Gy according to larger tumor sizes, while all IORT plans to 20 Gy. The mean EBRT D95 was 97.13% (SD ± 3.48) the SRS D99 99.91% (SD ± 0.35) and IORT D90 83.59% (SD ± 3.55). Accounting for only-boost approaches, the brain V12 was 49.68 cm3 (SD ± 26.70) and 16.94 cm3 (SD ± 13.33) (p&lt;0.001) for SRS and IORT, respectively. After adding EBRT results respectively to SRS and IORT doses, significant lower doses were found in the latter for mean Dmax of chiasma (p=0.01), left optic nerve (p=0.023), right (p=0.008) and left retina (p&lt;0.001). No significant differences were obtained for brainstem and cochleae.ConclusionDose escalation for Glioblastoma using IORT results in lower OAR exposure as conventional SRS.

scholarly journals Clinical Validation and Treatment Plan Evaluation Based on Auto-Delineation of the Clinical Target Volume for Prostate Cancer Radiotherapy

2022 ◽  
Author(s):  
Jing Shen ◽  
Yinjie TAO ◽  
Hui GUAN ◽  
Hongnan ZHEN ◽  
Lei HE ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Statistical Significance ◽  
Locally Advanced ◽  
Target Volume ◽  
Ct Scans ◽  
Dice Similarity Coefficient ◽  
Treatment Plans

Abstract Purpose Clinical target volumes (CTV) and organs at risk (OAR) could be auto-contoured to save workload. The goal of this study was to assess a convolutional neural network (CNN) for totally automatic and accurate CTV and OAR in prostate cancer, while also comparing anticipated treatment plans based on auto-contouring CTV to clinical plans. Methods From January 2013 to January 2019, 217 computed tomography (CT) scans of patients with locally advanced prostate cancer treated at our hospital were collected and analyzed. CTV and OAR were delineated with a deep learning based method, which named CUNet. The performance of this strategy was evaluated using the mean Dice similarity coefficient (DSC), 95th percentile Hausdorff distance (95HD), and subjective evaluation. Treatment plans were graded using predetermined evaluation criteria, and % errors for clinical doses to the planned target volume (PTV) and organs at risk(OARs) were calculated. Results The defined CTVs had mean DSC and 95HD values of 0.84 and 5.04 mm, respectively. For one patient's CT scans, the average delineation time was less than 15 seconds. When CTV outlines from CUNetwere blindly chosen and compared to GT, the overall positive rate in clinicians A and B was 53.15% vs 46.85%, and 54.05% vs 45.95%, respectively (P>0.05), demonstrating that our deep machine learning model performed as good as or better than human demarcation Furthermore, 8 testing patients were chosen at random to design the predicted plan based on the auto-courtoring CTV and OAR, demonstrating acceptable agreement with the clinical plan: average absolute dose differences of D2, D50, D98, Dmean for PTV are within 0.74%, and average absolute volume differences of V45, V50 for OARs are within 3.4%. Without statistical significance (p>0.05), the projected findings are comparable to clinical truth. Conclusion The experimental results show that the CTV and OARs defined by CUNet for prostate cancer were quite close to the ground reality.CUNet has the potential to cut radiation oncologists' contouring time in half. When compared to clinical plans, the differences between estimated doses to CTV and OAR based on auto-courtoring were small, with no statistical significance, indicating that treatment planning for prostate cancer based on auto-courtoring has potential.

O114 TUMOR VOLUME REGRESSION DURING NEOADJUVANT CHEMORADIOTHERAPY FOR ESOPHAGEAL CANCER: A PROSPECTIVE STUDY WITH WEEKLY MRI

2019 ◽  
Vol 32 (Supplement_2) ◽  
Author(s):  
Ingmar L Defize ◽  
Mick R Boekhoff ◽  
Alicia S Borggreve ◽  
Noriyoshi Takahashi ◽  
Jelle P Ruurda ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Tumor Volume ◽  
Tumor Regression ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Neoadjuvant Chemoradiotherapy ◽  
Linear Process ◽  
Relative Volume ◽  
Mri Scans ◽  
The Mean

Abstract Aim To assess changes in tumor volume during neoadjuvant chemoradiotherapy (nCRT) for esophageal cancer with weekly MRI. Background & Methods Neoadjuvant chemoradiotherapy (nCRT) for esophageal cancer can cause tumor regression, however data on the magnitude of the volumetric changes during nCRT are scarce. Tumor regression can induce changes in the thoracic anatomy, with smaller target volumes and displacement of organs at risk (OARs) in close proximity to the tumor target as a result. Adaptation of the radiotherapy treatment plan according to volumetric changes during treatment might reduce dose to the OARs while maintaining adequate target coverage. In the current study patients with histologically proven esophageal cancer undergoing nCRT for esophageal cancer underwent 6 MRI scans: 1 scan prior to nCRT and 5 weekly scans during treatment. Tumors were delineated on T2 weighted images by two gastrointestinal radiation oncologists and volumetric changes were assessed. Results A total of 164 MRI scans of 28 patients were included. The mean tumor volume at baseline was 45ml (SD ± 23ml). Tumor volume regression started after the first week of nCRT and appeared to be a linear process with significant declines in tumor volume every subsequent week (p-values <0.05). The mean relative volume regression was 25% (SD ±15) between baseline and the fifth week of treatment (Figure 1.) Conclusion This study shows a significant linear decrease in tumor volume after the first week of nCRT for esophageal cancer on weekly MRI. These findings suggest the possible benefit of radiotherapy plan adaptations during nCRT.

Dosimetric evaluation of 3 and/or 4 field radiation therapy of breast cancers: clinical experience

2020 ◽  
pp. 1-15
Author(s):  
Ernest Osei ◽  
Susan Dang ◽  
Johnson Darko ◽  
Katrina Fleming ◽  
Ramana Rachakonda
Keyword(s):  
Breast Cancer ◽  
Radiation Therapy ◽  
High Risk ◽  
Chest Wall ◽  
Treatment Plan ◽  
Breath Hold ◽  
Adjuvant Radiation ◽  
Node Positive ◽  
Treatment Plans ◽  
The Mean

Abstract Background: Breast cancer is the most commonly diagnosed cancer among women and the second leading cause of cancer-related death in Canadian women. Surgery is often the first line of treatment for low-risk early stage patients, followed by adjuvant radiation therapy to reduce the risk of local recurrence and prevent metastasis after lumpectomy or mastectomy. For high-risk patients with node positive disease or are at greater risk of nodal metastasis, radiation therapy will involve treatment of the intact breast or chest-wall as well as the regional lymph nodes. Materials and methods: We retrospectively evaluated the treatment plans of 354 patients with breast cancer with nodes positive or were at high risk of nodal involvement treated at our cancer centre. All patients were treated with a prescription dose of 50 Gy in 25 fractions to the intact breast or chest-wall and 50 Gy in 25 fractions to the supraclavicular region and, based on patient suitability and tolerance, were treated either using the deep inspiration breath hold (DIBH) or free-breathing (FB) techniques. Results: Based on patient suitability and tolerance, 130 (36·7%) patients were treated with DIBH and 224 (63·3%) with FB techniques. There were 169 (47·7%) patients treated with intact breast, whereas 185 (52·3%) were treated for post-mastectomy chest-wall. The mean PTV_eval V92%, V95%, V100% and V105% for all patients are 99·4 ± 0·7, 97·6 ± 1·6, 74·8 ± 7·9 and 1·5 ± 3·2%, respectively. The mean ipsilateral lung V10Gy, V20Gy and V30Gy are 30·0 ± 5·3, 22·4 ± 4·7 and 18·4 ± 4·3% for intact breast and 30·9 ± 5·8, 23·5 ± 5·4 and 19·4 ± 5·0% for post-mastectomy patients with FB, respectively. The corresponding values for patients treated using DIBH are 26·3 ± 5·9, 18·9 ± 5·0 and 15·6 ± 4·7% for intact breast and 27·5 ± 6·5, 20·6 ± 5·7 and 17·1 ± 5·2% for post-mastectomy patients, respectively. The mean heart V10Gy, V20Gy, is 1·8 ± 1·7, 0·9 ± 1·0 for intact breast and 3·1 ± 2·2, 1·7 ± 1·6 for post-mastectomy patients with FB, respectively. The corresponding values with the DIBH are 0·5 ± 0·7, 0·1 ± 0·4 for intact breast and 1·1 ± 1·4, 0·4 ± 0·7 for post-mastectomy patients, respectively. Conclusion: The use of 3 and/or 4 field hybrid intensity-modulated radiation therapy technique for radiation therapy of high-risk node positive breast cancer patients provides an efficient and reliable method for achieving superior dose uniformity, conformity and homogeneity in the breast or post-mastectomy chest-wall volume with minimal doses to the organs at risk. The development and implementation of a consistent treatment plan acceptability criteria in radiotherapy programmes would establish an evaluation process to define a consistent, standardised and transparent treatment path for all patients that would reduce significant variations in the acceptability of treatment plans.

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