Evaluation on dosimetric plan quality and treatment delivery time of dynamic jaw mode in TomoTherapy® for left-side breast cancer patients

Author(s):  
Sin Ting Chiu ◽  
Po Man Wu ◽  
Ka Fai Cheng ◽  
Pui Hei Fok ◽  
George Chiu

Abstract Background: Few studies claimed that dynamic jaw (DJ) mode in Helical TomoTherapy® (HT) could improve the cranio-caudal dose distribution without prolonging the treatment time in treating different types of cancer. Also, studies suggested that DJ with a wider 5 cm field width (FW) could replace fixed jaws (FJ) with 2.5 cm FW to reduce the delivery time with the sustainable plan quality. Yet, the study on breast cancer with supraclavicular fossa (SCF) nodal involvement using DJ mode in HT is limited. This study aims to evaluate the DJ mode retrospectively by comparing their dosimetric quality with normal tissue complication probability (NTCP) of organs at risk and treatment delivery time with FJ mode on treating left-side breast with SCF nodal involvement. Materials and methods: All post-mastectomy patients, who had been irradiated for left-side breast with SCF nodal involvement were selected retrospectively in this study. With the same dose constraint and prescription as the treated DJ2.5 plan, two extra plans using DJ mode with 5 cm FW(DJ5.0) and FJ mode with 2.5 cm FW (FJ2.5) were computed for plan comparison. Results: No statistical significance was found in all the parameters of PTV and OARs, except for V20 of whole lung. DJ5.0 received V20 in ipsilateral left lung than FJ2.5 and DJ2.5. However, the average delivery time of DJ5.0 was significantly lower than that of DJ2.5 and FJ2.5 by almost 40%. Conclusions: No statistical significance was found in those dosimetric and radiobiological parameters among three modes while the delivery time has greatly reduced by using DJ5.0. A shorter treatment time can minimise intra-fractional error and better the patient’s experience during treatment.

2021 ◽  
Author(s):  
Yun Zhang ◽  
Yuling Huang ◽  
Shenggou Ding ◽  
Xingxing Yuan ◽  
Yuxian Shu ◽  
...  

Abstract Background: To compare the dosimetric normal tissue complication probability (NTCP), secondary cancer complication probabilities (SCCP), and excess absolute risk (EAR) differences of volumetric modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) for left-sided breast cancer after mastectomy. Methods and materials: Thirty patients with left-sided breast cancer treated with post-mastectomy radiation therapy (PMRT) were randomly enrolled in this study. Both IMRT and VMAT treatment plans were created for each patient. Planning target volume (PTV) doses for the chest wall and internal mammary nodes, PTV1, and PTV of the supraclavicular nodes, PTV2, of 50 Gy were prescribed in 25 fractions. The plans were evaluated based on PTV1 and PTV2 coverage, homogeneity index (HI), conformity index, conformity number (CN), dose to organs at risk, NTCP, SCCP, EAR, number of monitors units, and beam delivery time. Results: VMAT resulted in more homogeneous chest wall coverage than did IMRT. The percent volume of PTV1 that received the prescribed dose of VMRT and IMRT was 95.9 ± 1.2% and 94.5 ± 1.6%, respectively (p < 0.001). The HI was 0.11 ± 0.01 for VMAT and 0.12 ± 0.02 for IMRT, respectively (p = 0.001). The VMAT plan had better conformity (CN: 0.84 ± 0.02 vs. 0.78 ± 0.04, p < 0.001) in PTV compared with IMRT. As opposed to IMRT plans, VMAT delivered a lower mean dose to the ipsilateral lung (11.5 Gy vs 12.6 Gy) and heart (5.2 Gy vs 6.0 Gy) and significantly reduced the V5, V10, V20, V30, and V40 of the ipsilateral lung and heart; only the differences in V5 of the ipsilateral lung did not reach statistical significance (p = 0.409). Although the volume of the ipsilateral lung and heart encompassed by the 2.5 Gy isodose line (V2.5) was increased by 6.7% and 7.7% (p < 0.001, p = 0.002), the NTCP was decreased by 0.8% and 0.6%, and SCCP and EAR were decreased by 1.9% and 0.1% for the ipsilateral lung. No significant differences were observed in the contralateral lung/breast V2.5, V5, V10, V20, mean dose, SCCP, and EAR. Finally, VMAT reduced the number of monitor units by 31.5% and the treatment time by 71.4%, as compared with IMRT. Conclusions: Compared with IMRT, VMAT is the optimal technique for PMRT patients with left-sided breast cancer due to better target coverage, a lower dose delivered, NTCP, SCCP, and EAR to the ipsilateral lung and heart, similar doses delivered to the contralateral lung and breast, fewer monitor units and a shorter delivery time.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Zhang ◽  
Yuling Huang ◽  
Shenggou Ding ◽  
Xingxing Yuan ◽  
Yuxian Shu ◽  
...  

Abstract Background To compare the dosimetric, normal tissue complication probability (NTCP), secondary cancer complication probabilities (SCCP), and excess absolute risk (EAR) differences of volumetric modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) for left-sided breast cancer after mastectomy. Methods and materials Thirty patients with left-sided breast cancer treated with post-mastectomy radiation therapy (PMRT) were randomly enrolled in this study. Both IMRT and VMAT treatment plans were created for each patient. Planning target volume (PTV) doses for the chest wall and internal mammary nodes, PTV1, and PTV of the supraclavicular nodes, PTV2, of 50 Gy were prescribed in 25 fractions. The plans were evaluated based on PTV1 and PTV2 coverage, homogeneity index (HI), conformity index, conformity number (CN), dose to organs at risk, NTCP, SCCP, EAR, number of monitors units, and beam delivery time. Results VMAT resulted in more homogeneous chest wall coverage than did IMRT. The percent volume of PTV1 that received the prescribed dose of VMRT and IMRT was 95.9 ± 1.2% and 94.5 ± 1.6%, respectively (p < 0.001). The HI was 0.11 ± 0.01 for VMAT and 0.12 ± 0.02 for IMRT, respectively (p = 0.001). The VMAT plan had better conformity (CN: 0.84 ± 0.02 vs. 0.78 ± 0.04, p < 0.001) in PTV compared with IMRT. As opposed to IMRT plans, VMAT delivered a lower mean dose to the ipsilateral lung (11.5 Gy vs 12.6 Gy) and heart (5.2 Gy vs 6.0 Gy) and significantly reduced the V5, V10, V20, V30, and V40 of the ipsilateral lung and heart; only the differences in V5 of the ipsilateral lung did not reach statistical significance (p = 0.409). Although the volume of the ipsilateral lung and heart encompassed by the 2.5 Gy isodose line (V2.5) was increased by 6.7% and 7.7% (p < 0.001, p = 0.002), the NTCP was decreased by 0.8% and 0.6%, and SCCP and EAR were decreased by 1.9% and 0.1% for the ipsilateral lung. No significant differences were observed in the contralateral lung/breast V2.5, V5, V10, V20, mean dose, SCCP, and EAR. Finally, VMAT reduced the number of monitor units by 31.5% and the treatment time by 71.4%, as compared with IMRT. Conclusions Compared with IMRT, VMAT is the optimal technique for PMRT patients with left-sided breast cancer due to better target coverage, a lower dose delivered, NTCP, SCCP, and EAR to the ipsilateral lung and heart, similar doses delivered to the contralateral lung and breast, fewer monitor units and a shorter delivery time.


Author(s):  
Madalyne Chamberlain ◽  
Jerome Krayenbuehl ◽  
Janita E. van Timmeren ◽  
Lotte Wilke ◽  
Nicolaus Andratschke ◽  
...  

Abstract Purpose Purpose of this study is to evaluate plan quality on the MRIdian (Viewray Inc., Oakwood Village, OH, USA) system for head and neck cancer (HNC) through comparison of planning approaches of several centers. Methods A total of 14 planners using the MRIdian planning system participated in this treatment challenge, centrally organized by ViewRay, for one contoured case of oropharyngeal carcinoma with standard constraints for organs at risk (OAR). Homogeneity, conformity, sparing of OARs, and other parameters were evaluated according to The International Commission on Radiation Units and Measurements (ICRU) recommendations anonymously, and then compared between centers. Differences amongst centers were assessed by means of Wilcoxon test. Each plan had to fulfil hard constraints based on dose–volume histogram (DVH) parameters and delivery time. A plan quality metric (PQM) was evaluated. The PQM was defined as the sum of 16 submetrics characterizing different DVH goals. Results For most dose parameters the median score of all centers was higher than the threshold that results in an ideal score. Six participants achieved the maximum number of points for the OAR dose parameters, and none had an unacceptable performance on any of the metrics. Each planner was able to achieve all the requirements except for one which exceeded delivery time. The number of segments correlated to improved PQM and inversely correlated to brainstem D0.1cc and to Planning Target Volume1 (PTV) D0.1cc. Total planning experience inversely correlated to spinal canal dose. Conclusion Magnetic Resonance Image (MRI) linac-based planning for HNC is already feasible with good quality. Generally, an increased number of segments and increasing planning experience are able to provide better results regarding planning quality without significantly prolonging overall treatment time.


2021 ◽  
Vol 100 (4) ◽  

Introduction: The purpose of this study was to compare the radiation dose to organs at risk for deep-inspiration breath hold (DIBH) and free-breathing (FB) radiotherapy in patients with lef-sided breast cancer undergoing adjuvant radiotherapy after partial mastectomy. Methods: One hundred patients with left-sided breast cancer underwent DIBH and FB planning computed tomography scans, and the 2 techniques were compared. Dose-volume histograms were analyzed for heart, left anterior descending coronary artery (LAD), and left lung. Results: Radiation dose to heart, LAD, and left lung was significantly lower for DIBH than for free breathing plans. The median mean heart dose for DIBH technique in comparison with FB was 1.21 Gy, and 3.22 Gy respectively; for LAD, 4.67 versus 24.71 Gy; and for left lung 8.32 Gy versus 9.99 Gy. Conclusion: DIBH is an effective technique to reduce cardiac and lung radiation exposure.


1993 ◽  
Vol 8 (2) ◽  
pp. 113-123 ◽  
Author(s):  
R. Molina ◽  
J. Jo ◽  
X. Filella ◽  
G. Zanon ◽  
J.J. Grau ◽  
...  

Mucin-like Carcinoma-associated Antigen (MCA) has been associated with many breast cancers. The aim of this study was to evaluate MCA in tumor tissue and serum as a potential tumor marker for prognosis and disease monitoring. MCA levels were determined in the tissue of 196 patients with primary breast cancer, 25 with metastatic disease and 25 patients with benign diseases, in pellet and/or cytosol. MCA levels were also determined in the serum of 50 patients with benign diseases, 148 with primary breast cancer (Mo), 150 with metastatic breast cancer (MT), and 200 with no clinical evidence of disease (NED). MCA tissue concentrations in pellet and cytosol were similar: 66.7 + 251 U/mg and 41.1 + 53 U/mg, respectively. No relationship between MCA levels and tumor size or nodal involvement was found. Higher MCA levels were observed in patients with ER + or PgR + tumors than in those with ER- or PgR- tumors (p < 0.01). Patients with MCA pellet concentrations lower than 10 U/mg of protein had shorter disease - free intervals (DFI) than those with higher values (p < 0.05). Abnormally high serum levels of MCA were found in 8% of patients with benign diseases, 4% of NED patients, 22% of Mo patients, and in 76% of MT cases. In primary breast cancer MCA values were related to tumor size and nodal involvement. A trend toward a lower DFI in patients with elevated presurgical MCA levels was observed but was of no statistical significance. These differences became statistically significant when patients were subdivided according to nodal status, with shorter DFI in those without nodal invasion (p < 0.05). In metastatic patients, changes in serum MCA were related to the tumor's response to treatment in 82% of cases. The highest MCA values were found in patients with liver or bone metastasis and the lowest values were found in those with locoregional recurrence. In conclusion, although MCA is not a specific tumor marker, it can be useful as a prognostic factor (tissue and serum) and in monitoring metastatic patients.


Neurosurgery ◽  
2014 ◽  
Vol 75 (4) ◽  
pp. 409-418 ◽  
Author(s):  
Evan M. Thomas ◽  
Richard A. Popple ◽  
Xingen Wu ◽  
Grant M. Clark ◽  
James M. Markert ◽  
...  

Abstract BACKGROUND: Volumetric modulated arc therapy (VMAT) has been shown to be feasible for radiosurgical treatment of multiple cranial lesions with a single isocenter. OBJECTIVE: To investigate whether equivalent radiosurgical plan quality and reduced delivery time could be achieved in VMAT for patients with multiple intracranial targets previously treated with Gamma Knife (GK) radiosurgery. METHODS: We identified 28 GK treatments of multiple metastases. These were replanned for multiarc and single-arc, single-isocenter VMAT (RapidArc) in Eclipse. The prescription for all targets was standardized to 18 Gy. Each plan was normalized for 100% prescription dose to 99% to 100% of target volume. Plan quality was analyzed by target conformity (Radiation Therapy Oncology Group and Paddick conformity indices [CIs]), dose falloff (area under the dose-volume histogram curve), as well as the V4.5, V9, V12, and V18 isodose volumes. Other end points included beam-on and treatment time. RESULTS: Compared with GK, multiarc VMAT improved median plan conformity (CIVMAT = 1.14, CIGK = 1.65; P &lt; .001) with no significant difference in median dose falloff (P = .269), 12 Gy isodose volume (P = .500), or low isodose spill (P = .49). Multiarc VMAT plans were associated with markedly reduced treatment time. A predictive model of the 12 Gy isodose volume as a function of tumor number and volume was also developed. CONCLUSION: For multiple target stereotactic radiosurgery, 4-arc VMAT produced clinically equivalent conformity, dose falloff, 12 Gy isodose volume, and low isodose spill, and reduced treatment time compared with GK. Because of its similar plan quality and increased delivery efficiency, single-isocenter VMAT radiosurgery may constitute an attractive alternative to multi-isocenter radiosurgery for some patients.


2021 ◽  
Vol 9 (3) ◽  
pp. 167-171
Author(s):  
Dr. Aparajeeta Aparajeeta ◽  
◽  
Dr. Ankita Mehta ◽  
Mr. N.S. Silambarasan ◽  
Dr. Piyush Kumar ◽  
...  

Background: The increasing patient load in radiotherapy centres demands selection of thetechnique that provides plans with optimal dosimetry in terms of target volume coverage, organs atrisk (OAR) sparing and a lesser treatment time. This study was designed to compare the two widelypractised conformal techniques, IMRT and VMAT in head and neck cancer patients in terms ofplanning target volume (PTV) coverage, OAR sparing and treatment delivery parameters. Materialsand methods: For ten postoperative head and neck cancer patients who had been treated by IMRTtechnique virtual VMAT plans were generated for study purposes. The dose prescribed to PTV was 60Gy in 30 fractions. The dose-volume parameters of PTV and OARs and the treatment deliveryparameters were compared amongst both the techniques. Statistical significance was calculatedusing paired ‘t’ test. Results: Both the plans were comparable in terms of dosimetry. The onlysignificant difference being better conformity in the IMRT plans. The dose to OARs was alsocomparable in both the techniques except for a significant reduction in the point dose to brainstemwith the IMRT technique. Given the treatment delivery parameters, there was a significant reductionin the treatment delivery time and monitor units with the VMAT technique compared to the IMRTtechnique. Conclusion: VMAT technique gave comparable plans to that of the IMRT technique interms of dosimetry but reduced the treatment time. It seems feasible in radiotherapy centres withincreased patient load.


2020 ◽  
Author(s):  
Nadia Pasinetti ◽  
Lilia Bardoscia ◽  
Luigi Spiazzi ◽  
Barbara Ghedi ◽  
Sara Pedretti ◽  
...  

Abstract Background: Radiotherapy (RT) improves local control and survival in breast cancer (BC) patients. However, risk of heart and lung side effects after post-operative left breast RT for breast cancer remain despite technological and technical RT advances. In a retrospective cohort we investigated if Active Breathing Coordinator (ABC) device can reduce risk of cardiopulmonary morbidity.Methods: we performed two different dosimetric analyses by Normal Tissue Complication Probability (NTCP) and Bio-Dose-Volume Histograms (Bio-DVH) in order to determine whether left breast RT using moderating deep inspiration breath-hold (mDIBH) with the Active Breathing Coordinator (ABC) device, may significantly reduce heart, left anterior descending coronary artery (LADCA) and lung radiation exposure during left breast RT performed with 3d-CRT technique.Results: Several dosimetric parameters were used in the present study to compare the treatment plans generated by FB and mDIBH images of sixty-nine consecutive patients treated between May 2012 and April 2016 at the Istituto del Radio Radiation Oncology Dept. All data derived by Bio-DVH and the heart NTCP calculation showed that ABC led to significant sparing of organs at risk compared with FB, expecially for the heart and LADCA. We also showed that the mDIBH technique significantly reduced left lung dose: in fact, through inflation, only low density lung tissue remains within the tangential field, thus avoiding its deterioration.Conclusions: Use of mDIBH gives a real advantage on breast cancer RT by reducing the radiation to the organs at risk (OARs) and consequently, the risk of cardiac and pulmonary late side effects.


2021 ◽  
Vol 2 ◽  
Author(s):  
Budhi Singh Yadav ◽  
Deepak Kumar Das ◽  
Narendra Kumar ◽  
Manphool Singhal ◽  
Ngangom Robert

Abstract Introduction In this study we compared radiation dose received by organs at risk (OARs) after breast conservation surgery(BCS) and mastectomy in patients with left breast cancer. Materials and methods Total 30 patients, 15 each of BCS and mastectomy were included in this study. Planning Computerised Tomography (CT) was done for each patient. Chest wall, whole breast, heart, lungs, LAD, proximal and distal LAD, and contra lateral breast was contoured for each patient. Radiotherapy plans were made by standard tangent field. Dose prescribed was 40Gy/16#/3 weeks. Mean heart dose, LAD, proximal and distal LAD, mean and V5 of right lung, and mean, V5, V10 and V20 of left lung, mean dose and V2 of contra lateral breast were calculated for each patient and compared between BCS and mastectomy patients using student’s T test. Results Mean doses to the heart, LAD, proximal LAD and distal LAD were 3.364Gy, 16.06Gy, 2.7Gy, 27.5Gy; and 4.219Gy, 14.653Gy, 4.306Gy, 24.6Gy, respectively for mastectomy and BCS patients. Left lung mean dose, V5, V10 and V20 were 5.96Gy, 16%, 14%, 12.4%; and 7.69Gy, 21%, 18% and 16% in mastectomy and BCS patients, respectively. There was no statistical significant difference in the doses to the heart and left lung between mastectomy and BCS. Mean dose to the right lung was significantly less in mastectomy as compared to BCS, 0.29Gy vs. 0.51Gy, respectively (p = 0.007). Mean dose to the opposite breast was significantly lower in patients with mastectomy than BCS (0.54Gy Vs 0.37Gy, p = 0.007). The dose to the distal LAD was significantly higher than proximal LAD both in BCS (24.6Gy Vs 4.3Gy, p = <0.0001) and mastectomy (27.5Gy Vs 2.7Gy, p = <0.0001) patients. Conclusion There was no difference in doses received by heart and left lung between BCS and mastectomy patients. Mean doses to the right lung and breast were significantly less in mastectomy patients.


2021 ◽  
Author(s):  
Liuwei Tang ◽  
Yojiro Ishikawa ◽  
Kengo Ito ◽  
Takaya Yamamoto ◽  
Rei Umezawa ◽  
...  

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


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