The impact of breast size on mean lung dose for patients receiving tangential radiotherapy to the whole breast

2016 ◽  
Vol 15 (2) ◽  
pp. 181-188
Author(s):  
Ashley Schembri ◽  
Susan Mercieca ◽  
Nick Courtier ◽  
Francis Zarb
Keyword(s):  
Significant Variation ◽  
Target Volume ◽  
Breast Size ◽  
Lung Dose ◽  
Breast Radiotherapy ◽  
Large Breast ◽  
Significant Difference ◽  
Mean Lung Dose ◽  
The Impact ◽  
Radiotherapy Treatment

AbstractPurposeTo explore the impact of breast size on mean lung dose (MLD) for patients receiving breast radiotherapy.MethodologyChest wall separation (CWS), volume of tissue receiving 95% isodose and MLD were measured on 80 radiotherapy treatment plans of patients receiving tangential radiotherapy treatment to the whole breast. Breast size was categorised as small (CWS<25 cm and planned target volume (PTV)<1,500 cm3) and large (CWS>25 cm and PTV>1500 cm3). Pearson’s correlation and independent sample t-test were used to analyse data.ResultsMLD was not affected by CWS (r=−0·13, p=0·24) nor volume of tissue receiving 95% isodose (r=−0·08, p=0·49). Significant variation between small and large breasts was noted for CWS (t=8·24, p=0·00) and volume of tissue receiving 95% isodose (t=5·68, p=0·00). No significant variation was noted between small and large breast for MLD (t=−0·26, p=0·80) and between left and right breasts for CWS (t=1·42, p=0·16) and volume of tissue receiving 95% isodose (t=−1·08, p=0·28). Significant difference between left (18–808 cGy) and right breast (325–365 cGy) was demonstrated for MLD (t=3·03, p=0·00).ConclusionThis study demonstrated lack of correlation between breast size and MLD. Further research is recommended for justification of alternative techniques for this subgroup of patients to provide optimised radiotherapy delivery.

PO-1142 Hypofractionated whole breast radiotherapy in large breast size: is it really a solved issue?

2021 ◽  
Vol 161 ◽  
pp. S950-S951
Author(s):  
R.R. Colcago ◽  
A. Cavallo ◽  
M.C. Magri ◽  
E. La Rocca ◽  
A. Vitullo ◽  
...  
Keyword(s):  
Breast Size ◽  
Breast Radiotherapy ◽  
Large Breast ◽  
Whole Breast Radiotherapy

Hypofractionated whole-breast radiotherapy in large breast size patients: is it really a resolved issue?

2021 ◽  
Vol 38 (9) ◽  
Author(s):  
Riccardo Ray Colciago ◽  
Anna Cavallo ◽  
Maria Chiara Magri ◽  
Angelo Vitullo ◽  
Eliana La Rocca ◽  
...  
Keyword(s):  
Breast Size ◽  
Breast Radiotherapy ◽  
Large Breast ◽  
Whole Breast Radiotherapy

Improving the accuracy of localisation in the radiotherapy treatment of head and neck, and brain cancer: some initial findings

2000 ◽  
Vol 2 (3) ◽  
pp. 125-132 ◽  
Author(s):  
M. J. McJury ◽  
R. Nakielny ◽  
D. Levy ◽  
J. Lilley ◽  
J. Conway ◽  
...  
Keyword(s):  
Head And Neck ◽  
Planning Process ◽  
Radiotherapy Planning ◽  
Ct Scans ◽  
Additional Patient ◽  
Post Contrast ◽  
Significant Difference ◽  
Mean Differences ◽  
The Impact ◽  
Radiotherapy Treatment

Aims: To investigate the impact on localisation of utilising contrast enhanced computed tomography (CT) scans and the formal input of a radiologist in the radiotherapy planning process.Method: Ten head and neck / brain patients had pre- and post-contrast CT scans in the treatment position. Over several months, their unenhanced and enhanced scans were re-contoured by the original oncologist, and a radiologist. These new contours were compared to the original unenhanced contours and differences in contour volume, geographical position and tolerance doses on the associated PTVs were evaluated.Results: The use of contrast lead to significant differences in the size of GTVs. Mean differences in GTVs of 32.8 % were significant at p=0.01. No significant impact on the position of the contour centre was noted. The impact of the radiologist lead to large differences in GTV (mean 20.5 %), but large SDs meant this result was not statistically significant. The contouring precision of the oncologist showed no significant difference for GTVs and PTVs.Conclusions: The use of contrast when planning the radiotherapy treatment for head and neck / brain patients was found to lead to significant differences in GTV size, a lesser effect on PTV definition and little impact on the position of the contour centre. It may have important implications for multi-phase treatments where the GTV (rather than the PTV) is targeted for boost doses. Differences due to the input of a radiologist appear to be considerable and require further investigation when additional patient numbers have been acquired to improve precision.

Quality Of Restored Steel Gas Pipes For Re-Application In Construction

2020 ◽  
pp. 31-41
Keyword(s):  
Impact Toughness ◽  
Significant Variation ◽  
Corrosion Damage ◽  
Mechanical Tests ◽  
Noticeable Effect ◽  
Significant Difference ◽  
Impact Bending ◽  
Thermal Influence ◽  
The Impact

The structure and mechanical properties of eight steel gas pipeline single-seam and double-seam pipes that were in operation were studied. It is shown that the degree of corrosion damage to pipe surfaces depends on the chemical composition of the steels. In the studied steels, a significant variation in the hydrogen content between neighboring volumes and the studied pipes was revealed. According to electron-fractographic analysis , there is no significant difference in the degree of embrittlement of the base metal, the weld and the zone of thermal influence. A noticeable effect of hydrogen absorption of steels on the coefficient of anisotropy of the impact toughness has been established, which causes a decrease in the impact toughness on transverse samples to a greater extent than on longitudinal ones. According to the results of mechanical tests for tensile and impact bending, it was found that the restored welded pipes are suitable for use in structures from the first to the fourth groups for the construction, repair and reconstruction of industrial and civil facilities. Naturally, this implies the need for their restoration repair.

scholarly journals CBCT image guidance in head and neck irradiation: the impact of daily and weekly imaging protocols

2015 ◽  
Vol 14 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Innocencia Nyarambi ◽  
Crispen Chamunyonga ◽  
Andrew Pearce
Keyword(s):  
Head And Neck ◽  
Target Volume ◽  
Setup Error ◽  
Imaging Data ◽  
Imaging Protocol ◽  
Setup Errors ◽  
Image Guided Radiotherapy ◽  
Significant Difference ◽  
The Mean ◽  
The Impact

AbstractPurposeThis study evaluated the impact of a daily and weekly image-guided radiotherapy protocols in reducing setup errors and setting of appropriate margins in head and neck cancer patients.Materials and methodsInterfraction and systematic shifts for the hypothetical day 1–3 plus weekly imaging were extrapolated from daily imaging data from 31 patients (964 cone beam computed tomography (CBCT) scans). In addition, residual setup errors were calculated by taking the average shifts in each direction for each patient based on the first three shifts and were presumed to represent systematic setup error. The clinical target volume (CTV) to planning target volume (PTV) margins were calculated using van Herk formula and analysed for each protocol.ResultsThe mean interfraction shifts for daily imaging were 0·8, 0·3 and 0·5 mm in the S-I (superior-inferior), L-R (left-right) and A-P (anterior-posterior) direction, respectively. On the other hand the mean shifts for day 1–3 plus weekly imaging were 0·9, 1·8 and 0·5 mm in the S-I, L-R and A-P direction, respectively. The mean day 1–3 residual shifts were 1·5, 2·1 and 0·7 mm in the S-I, L-R and A-P direction, respectively. No significant difference was found in the mean setup error for the daily and hypothetical day 1–3 plus weekly protocol. However, the calculated CTV to PTV margins for the daily interfraction imaging data were 1·6, 3·8 and 1·4 mm in the S-I, L-R and A-P directions, respectively. Hypothetical day 1–3 plus weekly resulted in CTV–PTV margins of 5, 4·2 and 5 mm in the S-I, L-R and A-P direction.ConclusionsThe results of this study show that a daily CBCT protocol reduces setup errors and allows setup margin reduction in head and neck radiotherapy compared to a weekly imaging protocol.

scholarly journals Impact of fiducial markers placements on the delineation of target volumes in radiation therapy for oesophageal cancer: final results of the FIDUCOR study

2020 ◽  
Author(s):  
Laurence Moureau-Zabotto ◽  
F. Caillol ◽  
A. Autret ◽  
M. Gilabert ◽  
J. Guiramand ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Ct Scan ◽  
Positive Impact ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Target Volume ◽  
Fiducial Markers ◽  
Distant Lymph Node Metastasis ◽  
Significant Difference ◽  
The Impact

Abstract Purpose This prospective monocentric phase II study (FIDUCOR-study) aimed at the assessment of the impact of fiducial markers (FMs) implantation on conformal chemo-radiation therapy (CRT) planning in esophageal carcinoma (EC) patients. Methods/materials Fifteen EC patients were enrolled in the study. Each patient underwent two simulation CT-scans before (CT1) and after (CT2) FMs implantation, in the same position. FMs (3 mm length gold markers, preloaded in a 22G needle) were implanted after sedation, under EUS and X-Ray guidance, and were placed at the tumor’s extremities, and in the visible lymph nodes. Target delineation and treatment plan were both performed first on CT1 with the assistance of, diagnosis-CT, gastroscopy- and EUS-details, and second on CT2 using FMs and CT-data. The value of FMs implantation was assessed by the difference of growth-tumor-volume (GTV) and clinical-target-volume (CTV) between CT1-based and CT2-based delineation. A significant difference was defined as a ≥5 mm-difference on axial(x) or coronal(y) slices, a ≥10mm-difference on sagittal slices, or a ≥20%-difference in GTV. The impact on dose distribution in organs at risk (OAR) (lung, heart, liver) was also studied. Results Between 09/2014 and 12/2015, 15 patients could achieve fiducial procedures, without any complication. One FM migration occurred. We observed a significant modification of the GTV-dimension in 100% of the cases (15/15, 95%CI: [78.2;100.0]), mainly due to a difference in sagittal dimension with a mean variation of 11.2 mm and a difference> 10 mm for 8/15 patients (53.3%). One patient had a significant isocenter displacement as high as 20 mm. The esophagus tumor was not seen on the CT-scan in one patient due to its small size. One patient had a distant lymph node metastasis not visible on CT-scan. We observed no significant impact on OAR distribution. Conclusion In our study, FMs-implantation appeared to have positive impact on accurate volume definition in EC-patients. Registration trial number NCT02526134 since the 06-18-2013 ; URL https://clinicaltrials.gov/ct2/show/NCT02526134

scholarly journals Comparative study between Acuros XB algorithm and Anisotropic Analytical Algorithm in the case of heterogeneity for the treatment of lung cancer

2018 ◽  
Vol 24 (3) ◽  
pp. 115-119
Author(s):  
Mohammed El Adnani Krabch ◽  
Abdelouahed Chetaine ◽  
Abdelati Nourreddine ◽  
Fatim Zohra Er-Radi ◽  
Laila Baddouh
Keyword(s):  
Lung Cancer ◽  
At Risk ◽  
Heterogeneous Media ◽  
Maximum Dose ◽  
Organs At Risk ◽  
Target Volume ◽  
Conformity Index ◽  
Acuros Xb ◽  
Significant Difference ◽  
The Impact

Abstract The aim of this study was to investigate the impact of heterogeneity on the dose calculation for two algorithms implemented in the TPS “Analytical Anisotropic Algorithm (AAA) and Acuros XB” and validated the use of Acuros XB algorithm in clinical routine. First, we compare the dose calculated by these algorithms and the dose measured at the given point P, which is found after heterogeneity insert. Second, we extend our work on clinical cases that present a complex heterogeneity. By evaluating the impact of the choice of the algorithm on the dose coverage of the tumor, and the dose received by the organs at risk for 20 patients affected by lung cancer. The result of our phantom study showed a good agreement with several studies that showed the superiority of the Acuros XB over the AAA in predicting dose when it concerns heterogeneous media. The treatment plans for 20 lung cancers were calculated by two algorithms AAA and Acuros XB, the results show a statistical significant difference between algorithms for Homogeneity Index and the maximum dose of planning target volume (HI: 0.11±0.01 vs 0.05±0.01 p = 0.04; Dmax: 69.30±3.12 vs 68.51±2.64 p = 0.02). Instead, no statistically significant difference was observed for conformity index CI and mean dose (CI: 0.98±0.18 vs 0.99±0.14 p = 0.33; Dmean: 66.3±0.65 vs 66.10 ±0.61 p = 0.54). For organs at risk, the maximum dose for spinal cord, mean dose and D37 % of lung minus GTV (dose receiving 37% of lung volume) were found to be lower for AAA plans than Acuros XB and the differences were statistically significant (p<0.05). For the heart D33% and D67% were found to be higher for AAA plans than Acuros XB and the differences were statistically significant (p<0.05), but No difference was observed for D100% of the heart. The use of the AXB algorithm is suitable in the case of presence of heterogeneity, because it allows to have a better accuracy close to the Monte Carlo calculation.

Trends and Correlates of Mean Lung Dose in Patients Receiving Breast Radiotherapy in a Single Institution from 2014 to 2018

2020 ◽  
Vol 32 (10) ◽  
pp. 647-655
Author(s):  
E. McKenzie ◽  
Y. Razvi ◽  
M. Wronski ◽  
L. Zhang ◽  
S. Bosnic ◽  
...  
Keyword(s):  
Lung Dose ◽  
Single Institution ◽  
Breast Radiotherapy ◽  
Mean Lung Dose

Tumour bed localisation after oncoplastic breast conservative surgery: a comparative contouring study

2018 ◽  
Vol 18 (1) ◽  
pp. 63-69
Author(s):  
Radwa Fawzy ◽  
Shaimaa Lasheen ◽  
Maha Kamaleldin ◽  
Rasha Wessam ◽  
Emad Khallaf ◽  
...  
Keyword(s):  
Normal Tissue ◽  
Conservative Surgery ◽  
Target Volume ◽  
Oncoplastic Breast Surgery ◽  
Surgical Clips ◽  
Breast Conservative Surgery ◽  
Boost Irradiation ◽  
Volume Delineation ◽  
Significant Difference ◽  
The Impact

AbstractPurposeTo investigate the modalities of tumour bed (TB) localisation of target volume delineation [clinically computed tomography (CT), ultrasound (US) compared with surgical clips-guided] and the impact of their differences in delineated TB volumes.Material and methodsIn total, 27 patients who underwent oncoplastic breast conservative surgery with surgical clips insertion (at least three) were included. CT and US imaging for TB localisation were done 3–4 weeks post-operatively in the same treatment position. TB was delineated four times, guided by surgical clips, clinical data, CT (seroma) and US. A plan was done for each TB delineated. The four delineated volumes were compared regarding the volumetric differences, the geographical miss index (GMI) and the overlap index.ResultsComparing the four modalities, median TB volume was for clinical (60.7), CT (60.8) and US (49.3) cm3, in comparison with 59.7 cm3 for clips, p=0.05. Median of GMI (represented the tissue at risk of recurrence and not had been treated) was for clinical (61.8), CT (45) and US (62.4)%, with significant difference of p=0.02. Median of normal tissue index (normal tissue has been included unnecessarily) was for clinical (59.5), CT (49.6) and US (62.3)%, p=0.17. Overlap index with clips-guided was for clinical (0.36), CT (0.42) and US (0.35) with significance of p=0.04. Median superior/inferior direction was 0.72, −0.03 and −0.2 cm for clinical, CT and US, respectively, with significant value of p=0.02, whereas the anterior–posterior was −0.07, −0.15 and −0.09 cm, p-value=0.45 and the medio–lateral was 0.4, −0.13 and 0.09 cm, p=0.60.ConclusionSignificant differences in shifts and indices were detected between each of modalities compared with surgical clips. Thus, in the setting of oncoplastic breast surgery, surgical clips should be routinely used for TB localisation. In view of the larger volumes of breast tissue excised and the extensive remodelling that are inherent to oncoplastic procedures, the concept of TB boost irradiation should be re-challenged.

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