scholarly journals Helical tomotherapy with a complete-directional-complete block technique effectively reduces cardiac and lung dose for left-sided breast cancer

2020 ◽  
Vol 93 (1108) ◽  
pp. 20190792 ◽  
Author(s):  
Hsin-Pei Yeh ◽  
Yu-Chuen Huang ◽  
Li-Ying Wang ◽  
Pei-Wei Shueng ◽  
Hui-Ju Tien ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Helical Tomotherapy ◽  
Organs At Risk ◽  
Intensity Modulated Radiation Therapy ◽  
Target Volume ◽  
Conformity Index ◽  
Breast Cancer Patients ◽  
Lung Dose ◽  
The Mean

Objectives: To evaluate the feasibility and optimal restricted angle of the complete-directional-complete block (CDCB) technique in helical tomotherapy (HT) by including regional nodal irradiation (RNI) with the internal mammary node (IMN) in left-sided breast cancer. Methods: Ten left-sided breast cancer patients treated with 50 Gy in 25 fractions were compared with five-field intensity-modulated radiation therapy (5F-IMRT) and six types of HT plans. In the HT plans, complete block (CB), organ-based directional block (OBDB) and CDCB with different restricted angles were used. Results: The conformity index (CI) between the CDCB0,10,15,20 and 5F-IMRT groups was similar. Compared to CB, OBDB and 5F-IMRT, CDCB20 resulted in a decreased ipsilateral mean lung dose. The low-dose region (V5) of the ipsilateral lung in OBDB (84.0%) was the highest among all techniques (p < 0.001). The mean dose of the heart in CB was significantly reduced (by 11.5–22.4%) compared with other techniques. The V30 of the heart in CDCB20 (1.9%) was significantly lower than that of CB, OBDB and 5F-IMRT. Compared to the mean dose of the left anterior descending (LAD) artery of 5F-IMRT (27.0 Gy), CDCB0, CDCB10, CDCB15, CDCB20 and OBDB reduced the mean dose effectively by 31.7%, 38.3%, 39.6%, 42.0 and 56.2%, respectively. Considering the parameters of the organs-at-risk (OARs), CDCB10,15,20 had higher expectative values than the other techniques (p = 0.01). Conclusions: HT with the CDCB technique is feasible for treating left-sided breast cancer patients. The CDCB10-20 techniques not only achieved similar planning target volume coverage, homogeneity and dose conformity but also allowed better sparing of the heart and bilateral lungs. Advances in knowledge: For left-sided breast cancer patients whose RNI field includes the IMN, heart avoidance is an important issue. The CDCB technique achieved good PTV coverage, homogeneity and dose conformity and allowed better sparing of the mean dose of the lung, the LAD artery, and the heart and reduced the V30 of the heart.

scholarly journals Dosimetric Comparison of Three Radiotherapy Techniques in Irradiation of Left-Sided Breast Cancer Patients after Radical Mastectomy

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jian Hu ◽  
Guang Han ◽  
Yu Lei ◽  
Ximing Xu ◽  
Wei Ge ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Radical Mastectomy ◽  
Target Volume ◽  
Conformity Index ◽  
Breast Cancer Patients ◽  
Ipsilateral Lung ◽  
Significant Difference

Introduction. This study is aimed at evaluating the dosimetric differences among target segmented planning (TSP), conventional 9-field intensity modulated radiation therapy (9FIMRT) planning, and volumetric modulated arc therapy (VMAT) planning for postmastectomy radiotherapy of left-sided breast cancer patients. Material and Methods. Fifteen left-sided breast cancer patients who underwent radical mastectomy were enrolled. In TSP, the planning target volume (PTV) was divided into four regions (supra/infraclavicular, chest wall, external mammary region, and internal mammary region), and each individual PTV region was treated with respective fixed fields. Results. The VMAT plans showed superior to PTV dose conformity index (CI), homogeneity index (HI), protection of the ipsilateral lung, monitor units (MUs), and maximum dose (Dmax) to the contralateral breast compared with TSP and 9FIMRT plans. The TSP provided better protection for Dmean of the heart and left ventricle (p<0.05). A dose for left anterior descending artery from the three techniques had no significant difference. Compared with the 9FIMRT plans, the V5Gy (%) and V10Gy (%) for the ipsilateral lung were significantly reduced with TSP and VMAT (p<0.05). The V5Gy (%) and V10Gy (%) for the ipsilateral lung turned out to be similar between VMAT and TSP techniques. Conclusions. Our study indicates that VMAT should be a better choice of radiotherapy for left-sided breast cancer patients after radical mastectomy. If VMAT is unavailable, 9FIMRT can achieve better CI and HI values and be more MU-efficient compared with TSP; however, TSP can effectively reduce the low dose volume of the ipsilateral lungs and heart.

A Dosimetrical Analysis of the Magnitude of Isocenter Shifts Using CT-on-Rails Guided Online Adaptive Planning for Left Breast Cancer Patients Treated by Intensity Modulated Radiation Therapy

2020 ◽  
Vol 106 (1_suppl) ◽  
pp. 32-32
Author(s):  
K Mashhour ◽  
S Eliteo ◽  
W Hashem
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Organs At Risk ◽  
Intensity Modulated Radiation Therapy ◽  
Target Coverage ◽  
Breast Cancer Patients ◽  
Adaptive Planning ◽  
Intensity Modulated ◽  
The Mean ◽  
3D Crt

Introduction: This study was conducted to check the accuracy and validity of an automated adaptive planning (AAP) method which combines automated re-contouring and re-planning to check for inter-fractional anatomical changes in breast cancer patients receiving intensity modulated radiation therapy (IMRT) based on a weekly computed tomography (CT)-on rails images dosimetrically viewing the magnitude of difference in isocenter shifts and the degree of dose deviations regarding target coverage and dose received by organs at risk. Methods and Materials: Twenty left sided conservative breast cancer patients were selected for IMRT treatment. Automatic generation of the contours on each repeat CT image was performed by mapping the contours from the planning CT image using deformable image registration. 3D- CRT and IMRT plans were automatically recalculated for each patient. The magnitude of isocenter shifts in postero-anterior (PA), cranio-caudal (CC) and right-left (RL) directions was calculated and the degree of dose deviations regarding target coverage and dose received by organs at risk. Results: In the PA,CC and RL directions, 9.2%, 11.4% and 6.4% of the 100 CT scans didn’t require any position adjustments. The mean isocenter shifts and standard deviation (SD) were 0.5 & 0.6 +/- 1.1mm, 0.3 &0.4 +/- 0.5mm and 0.2 & 0.4+/- 0.6mm for the IMRT and 3D-CRT plans in the PA,CC and RL directions, respectively. 74.1%, 65.1%, and 55.8% required a shift of 1 - 3 mm; 10.5%, 23.9%, and 33.2% required a shift of 3 - 5mm; and 1.5%, 3.3%, and 5.4% required a shift of more than 5 mm, respectively. With respect to target coverage, the D90[Gy] for the breast CTV was 46.2 Gy and 45.6 for the IMRT and 3D-CRT plans. The mean doses to the heart and left lung were reduced by 5.5 %, 3.7 Gy and 4.1%, 2.6 Gy using the AAP method. Conclusions: The fully automated AAP method using CT on rails for online re-planning was effective in reducing the magnitude of isocenter shifts and compensating for target volume coverage underdosing and higher doses perceived by risk organs caused by anatomical inter-fractional changes in breast cancer patients.

scholarly journals Prospective superficial EPR in-vivo dosimetry study during hypofractionated radiotherapy of breast cancer patients treated with helical tomotherapy

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Sebastian Höfel ◽  
Matteo Gandalini ◽  
Michael K. Fix ◽  
Malte Drescher ◽  
Felix Zwicker
Keyword(s):  
Breast Cancer ◽  
Total Dose ◽  
Cancer Patients ◽  
Helical Tomotherapy ◽  
Planning System ◽  
In Vivo Dosimetry ◽  
Breast Cancer Patients ◽  
Displacement Vectors ◽  
The Mean

Abstract Background In-vivo dosimetry (IVD) is a patient specific measure of quality control and safety during radiotherapy. With regard to current reporting thresholds for significant occurrences in radiotherapy defined by German regulatory authorities, the present study examines the clinical feasibility of superficial electron paramagnetic resonance (EPR) IVD of cumulative total doses applied to breast cancer patients treated with helical intensity-modulated radiotherapy (tomotherapy). Methods In total, 10 female patients with left- or right-sided breast cancer were enrolled in this prospective IVD study. Each patient received a hypofractionated whole breast irradiation. A total median dose of 42.4 Gy in 16 fractions (5 fractions per week) was prescribed to the planning target volume. The treatments were completely delivered using helical tomotherapy and daily image guidance via megavoltage CT (MVCT). For each patient, three EPR dosimeters were prepared and placed at distinct locations on the patient’s skin during the delivery of all fractions. Two dosimeters were placed next to the ipsilateral and contralateral mammilla and one dosimeter was placed ventrally to the thyroid (out-of-primary-beam). The total doses delivered to the dosimeters were readout after all fractions had been administered. The measured total dose values were compared to the planned dose values derived from the treatment planning system (TPS). Daily positional variations (displacement vectors) of the ipsilateral mammilla and of the respective dosimeter were analyzed with respect to the planned positions using the daily registered MVCT image. Results Averaged over all patients, the mean absolute dose differences between measured and planned total dose values (± standard deviation (SD)) were: 0.49 ± 0.85 Gy for the ipsilateral dosimeter, 0.17 ± 0.49 Gy for the contralateral dosimeter and -0.12 ± 0.30 Gy for the thyroid dosimeter. The mean lengths of the ipsilateral displacement vectors (± SD) averaged over all patients and fractions were: 10 ± 7 mm for the dosimeter and 8 ± 4 mm for the mammilla. Conclusion Superficial EPR IVD is suitable as additional safeguard for dose delivery during helical tomotherapy of breast cancer. Despite positional uncertainties in clinical routine, the observed dose deviations at the ipsilateral breast were on average small compared to national reporting thresholds for total dose deviations (i.e. 10%/4 Gy). EPR IVD may allow for the detection of critical dose errors during whole breast irradiations.

scholarly journals Evaluation of DIBH and VMAT in Hypofractionated Radiotherapy for Left-sided Breast Cancers After Breast-conserving Surgery: a Planning Study

2021 ◽  
Author(s):  
Liuwei Tang ◽  
Yojiro Ishikawa ◽  
Kengo Ito ◽  
Takaya Yamamoto ◽  
Rei Umezawa ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Organs At Risk ◽  
Left Lung ◽  
Breast Conserving Surgery ◽  
Left Breast ◽  
Breath Hold ◽  
Breast Cancer Patients ◽  
Lung Dose ◽  
Dose Reductions

Abstract Background This paper aims to compare dosimetric parameters of the organs at risk (OARs) among three different radiotherapy (RT) modalities in left breast cancer patients after breast-conserving surgery (BCS). Methods Eleven patients with left breast cancer after BCS were enrolled and underwent CT simulation in the free breathing (FB) and deep inspiration breath hold (DIBH) position. Three-dimensional radiotherapy (3DCRT) and volumetric modulated arc therapy (VMAT) plans were generated for each patient in the DIBH position. A 3DCRT plan was also created in the FB position. Dose-volume histogram (DVH) was used to analyze each evaluation index of OARs. The principal outcome was heart dose, left anterior descending coronary artery (LADCA) dose and left lung dose.Results For the 3D-CRT plans, significant dose reductions were demonstrated in all evaluation parameters to heart, LADCA and left lung dose in the DIBH position compared with the FB position (p < 0.05). In DIBH position, significant dose reductions were founded in heart and LADCA in VMAT plan compared to 3DCRT plan (p < 0.05). There were no significant differences between 3DCRT and VMAT plan for the left lung dose in DIBH position.Conclusion DIBH and VMAT could reduce dosimetric parameters of the OARs in left breast cancer patients after BCS. RT plans for left breast cancer after BCS can be optimized by DIBH and VMAT techniques to minimize radiation-induced toxicity

scholarly journals MRI reduces variation of contouring for boost clinical target volume in breast cancer patients without surgical clips in the tumour bed

2017 ◽  
Vol 51 (2) ◽  
pp. 160-168 ◽  
Author(s):  
Noora Al-Hammadi ◽  
Palmira Caparrotti ◽  
Saju Divakar ◽  
Mohamed Riyas ◽  
Suparna Halsnad Chandramouli ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Clinical Target Volume ◽  
Breast Conserving Surgery ◽  
Target Volume ◽  
Observer Variation ◽  
Breast Cancer Surgery ◽  
Conformity Index ◽  
Breast Cancer Patients ◽  
Ct And Mri

Abstract Background Omitting the placement of clips inside tumour bed during breast cancer surgery poses a challenge for delineation of lumpectomy cavity clinical target volume (CTVLC). We aimed to quantify inter-observer variation and accuracy for CT- and MRI-based segmentation of CTVLC in patients without clips. Patients and methods CT- and MRI-simulator images of 12 breast cancer patients, treated by breast conserving surgery and radiotherapy, were included in this study. Five radiation oncologists recorded the cavity visualization score (CVS) and delineated CTVLC on both modalities. Expert-consensus (EC) contours were delineated by a senior radiation oncologist, respecting opinions of all observers. Inter-observer volumetric variation and generalized conformity index (CIgen) were calculated. Deviations from EC contour were quantified by the accuracy index (AI) and inter-delineation distances (IDD). Results Mean CVS was 3.88 +/− 0.99 and 3.05 +/− 1.07 for MRI and CT, respectively (p = 0.001). Mean volumes of CTVLC were similar: 154 +/− 26 cm3 on CT and 152 +/− 19 cm3 on MRI. Mean CIgen and AI were superior for MRI when compared with CT (CIgen: 0.74 +/− 0.07 vs. 0.67 +/− 0.12, p = 0.007; AI: 0.81 +/− 0.04 vs. 0.76 +/− 0.07; p = 0.004). CIgen and AI increased with increasing CVS. Mean IDD was 3 mm +/− 1.5 mm and 3.6 mm +/− 2.3 mm for MRI and CT, respectively (p = 0.017). Conclusions When compared with CT, MRI improved visualization of post-lumpectomy changes, reduced interobserver variation and improved the accuracy of CTVLC contouring in patients without clips in the tumour bed. Further studies with bigger sample sizes are needed to confirm our findings.

Non-coplanar VMAT improves plan quality for locoregional radiotherapy of left-sided breast cancer with internal mammary nodes

2020 ◽  
Author(s):  
Yuan Xu ◽  
Pan Ma ◽  
Zhihu Hu ◽  
Yuan Tian ◽  
Kuo Men ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Organs At Risk ◽  
Left Lung ◽  
Breast Conserving Surgery ◽  
Target Volume ◽  
Conformity Index ◽  
Internal Mammary Nodes ◽  
Significant Difference ◽  
Internal Mammary ◽  
The Mean

Abstract Purpose A planning study was performed to evaluate the feasibility of non-coplanar volume modulated arc therapy (ncVMAT) for locoregional radiotherapy of left-sided breast cancer with internal mammary nodes. Methods and materials Ten patients with left-sided breast cancer after breast conserving surgery were retrospectively studied. The planning target volumes (PTV) were contoured encompassing the whole breast/chestwall, internal mammary nodes (IMN) and supraclavicular nodal (SCN) region. For each patient, ncVMAT plan with 4 partial arcs composing of two coplanar arcs and two non-coplanar arcs with couch rotating to 90˚ was generated. The prescription dose was normalized to cover 95% of PTV with 50 Gy delivering in 25 fractions. For each ncVMAT plan, dosimetric parameters were compared with coplanar VMAT (coVMAT) plan optimizing with identical coplanar beam angle arrangement. Results With ncVMAT, the mean conformity index of the whole PTV increased from 0.82±0.02 to 0.86±0.01 (p=0.005), and there was no significant difference for the homogeneity index. The mean coverage of internal mammary target volume (PTVimn) with ncVMAT increased from 88.77±3.07% to 91.67±3.84% comparing with coVMAT (p=0.005). Meanwhile, the V55 in PTVscn and PTVimn decreased significantly from 5.76±6.03%, 13.73±7.77% to 2.94±3.93%, 3.75±3.36%, separately (p<0.01). For organs at risk, the average V30, V20, V10, V5 and Dmean of heart decreased from 5.13±3.22%, 12.18±7.29%, 33.98±15.73%, 72.03±16.79% and 10.47±2.97 Gy to 4.86±2.54%, 9.35±5.43%, 25.16±12.42%, 62.27±13.18% and 9.08±2.34 Gy, separately (p<0.01). Furthermore, ncVMAT significantly reduced the mean V20, V10, V5, Dmean of left lung, and V10, V5, Dmean of contralateral lung (p<0.01). A better sparing of LAD descending coronary artery and right breast were also shown with ncVMAT (p<0.01). Conclusions Compared to coVMAT, ncVMAT provides better conformity, lower V55 in PTVscn and PTVimn, better coverage of PTVimn, better dose sparing in heart, bilateral lung, LAD and right breast for locoregional radiotherapy of left-sided breast cancer with internal mammary nodes, which potentially increase the local control in IMN and reduce the risk of deleterious effects.

Dosimetric comparison of radiotherapy plans for left-sided breast cancer patients in rolled versus supine body position.

2011 ◽  
Vol 29 (27_suppl) ◽  
pp. 124-124
Author(s):  
M. L. Tao ◽  
N. Mikolajczyk ◽  
B. Martyn ◽  
L. E. Botnick
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Body Position ◽  
Organs At Risk ◽  
Left Lung ◽  
Breast Cancer Patients ◽  
Dose Volume Histograms ◽  
Increased Risk ◽  
The Mean ◽  
The Right

124 Background: Left-sided breast cancer patients receiving whole breast radiation therapy (WBRT) are potentially at increased risk for cardiac morbidity. We evaluated heart sparing of left-sided breast cancer patients when placed in the rolled vs. the standard supine body position for WBRT. Methods: Ten patients with left-sided breast cancer underwent planning CT scans in 2 different positions: supine and rolled to the right to allow for the heart to drop away from the chest wall. Patients were immobilized using vacuum cradles. The left lung, opposite breast, stomach, heart, left ventricle (LV), and left anterior descending coronary artery (LAD) were defined as organs at risk (OARs). Comparison 3D conformal tangential field plans were generated for each patient. Dose-volume histograms (DVHs) of the planning target volume (PTV) and OARs were examined. Results: All plans met PTV dose coverage and homogeneity criteria of V95 > 95% and maximal dose < 108. Median V105 for PTV was 12.75% (range, 2.5-16%). None of these parameters differed either statistically or clinically between plans done with the patient supine or rolled. The maximal doses to the opposite breast and stomach were also not significantly different between the 2 positions. The right lung V20 was similar for the 2 positions, 11.1% and 12%. Although there were no significant differences in the mean and max doses to the heart or LV, the mean heart dose decreased by 18-70% in 6 patients in the rolled vs. supine position and increased by 2.7-31.5% in 4 patients. The mean dose to the LAD and the LAD V10 and V15 were significantly decreased when the patient was rolled: 17.1 vs. 29.5 Gy, 41.1% vs. 62.6% and 40% vs. 66.7% (p < .05), respectively. Six patients had superior plans when in the rolled position with substantial differences in the mean and/or max doses and/or DVHs for the heart, LV and LAD. The remaining 4 patients had no overall improvement or worsening of the plan when the patient was rolled vs. supine. Conclusions: For patients with left-sided breast cancer receiving WBRT, the rolled position potentially reduces dose to the heart and its substructures without compromising the coverage and homogeneity of the PTV, hence limiting the need for IMRT.

Comparison between different boost dose delivery techniques to the tumor bed of right sided breast cancer patients.

2017 ◽  
Vol 13 (1) ◽  
pp. 4605-4617
Author(s):  
Aly Mahmoud El-Hdidy
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Target Location ◽  
Breast Cancer Patients ◽  
Photon Beams ◽  
Lung Dose ◽  
Dose Volume Histograms ◽  
Tumor Bed ◽  
Boost Dose ◽  
Treatment Plans

Comparisons between three different techniques by which the boost dose was delivered to the tumor bed were carried out , aiming to present the best technique of treatment for right breast cancer patients.In this study, ten right sided breast cancer computed tomography (CT) scans were selected for ten early right breast cancer patients. We made three different treatment plans for each patient CT using three different irradiation techniques to deliver a prescribed boost dose of 10 Gy in 5 fractions to the boost PTV. In the first technique, two tangential photon beams were used, in the second technique we, two oblique photon beams were used and in the third technique, a single electron beam was used. The comparative analyses between the three techniques were performed by comparing the boost PTV- dose volume histograms (DVHs), the ipsilateral breast (right breast) DVHs, the ipsilateral lung (right lung) DVHs and the heart DVHs of the three techniques for each patient. Furthermore the dose that covering 100% , 95% of the volume (D100% , D95%) and the volume covered by 95% of the dose (V95%)of  the boost PTV of all techniques, were calculated for each patient to investigate the dose coverage of the target.Results showed that there were variations of the dose received by tumor bed, right breast and OARs depending on the technique used and the target location and size. A decrease of D100% than 90% of the prescribed dose was observed with the 3rd technique for patients 8, 9 and 10, and was observed with the 2nd technique for patient 5. A reduction of right breast dose was observed when the 3rd technique was use in comparison with the 1st and the 2nd techniques for patients 1, 2, 3, 4, 6 and 8.  Also reduction of right breast was observed when the 2nd technique used in comparison with 1st technique. An increase of lung dose was observed with the 3rd technique for patients 1, 2, 5 and 6, also was observed with 2nd technique in patient 3, 5 and 7. A decrease of lung dose was observed with the 1st technique for patients 2, 4, 5, 6, 7, 8 and 9An individualized treatment, several plans using different irradiation techniques should be developed for each patient individually to reach the best boost PTV dose coverage with minimal OARs’ dose. 

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