Accelerated hypofractionated radiotherapy for chest wall and nodal irradiation using hybrid techniques

2021 ◽  
pp. 1-7
Author(s):  
Karunakaran Balaji ◽  
Velayudham Ramasubramanian
Keyword(s):  
Chest Wall ◽  
Treatment Time ◽  
Organs At Risk ◽  
High Dose ◽  
Breast Cancer Patients ◽  
Treatment Delivery ◽  
Efficient Treatment ◽  
Hybrid Techniques ◽  
Target Volumes ◽  
Internal Mammary

Abstract Aim: This study compares three different hybrid plans, for left-sided chest wall (CW) and nodal stations irradiation using a hypofractionated dose regimen. Materials and methods: Planning target volumes (PTVs) of 25 breast cancer patients that included CW, supraclavicular (SCL) and internal mammary node (IMN) were planned with 3 different hybrid techniques: 3DCRT+IMRT, 3DCRT+VMAT and IMRT+VMAT. All hybrid plans were generated with a hypofractionated dose prescription of 40·5 Gy in 15 fractions. Seventy per cent of the dose was planned with the base-dose component and remaining 30% of the dose was planned with the hybrid component. All plans were evaluated based on the PTVs and organs at risk (OARs) dosimetric parameters. Results: The results for PTVs parameters have shown that the 3DCRT+IMRT and 3DCRT+VMAT plans were superior in uniformity index to the IMRT+VMAT plan. The OARs dose parameters were comparable between hybrid plans. The IMRT+VMAT plan provided a larger low dose volume spread to the heart and ipsilateral lung (p < 0·001). The 3DCRT+VMAT plan required less monitor units and treatment time (p = 0·005) than other plans. Conclusion: The 3DCRT+VMAT hybrid plan showed superior results with efficient treatment delivery and provide clinical benefit by reducing both low and high dose levels.

scholarly journals Treatment planning for MLC based robotic radiosurgery for brain metastases: plan comparison with circular fields and suggestions for planning strategies

2017 ◽  
Vol 3 (2) ◽  
pp. 151-154
Author(s):  
Daniela Schmitt ◽  
Rami El Shafie ◽  
Sebastian Klüter ◽  
Nathalie Arians ◽  
Kai Schubert ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Low Dose ◽  
Treatment Time ◽  
Conformity Index ◽  
High Dose ◽  
Gradient Index ◽  
Plan Comparison ◽  
Robotic Radiosurgery ◽  
Target Volumes ◽  
Beam Transmission

AbstractTo evaluate the possible range of application of the new InCise2 MLC for the CyberKnife M6 system in brain radiosurgery, a plan comparison was made for 10 brain metastases sized between 1.5 and 9cm3 in 10 patients treated in a single fraction each. The target volumes consist of a PTV derived by expanding the GTV by 1mm and were chosen to have diversity in the cohort regarding regularity of shape, location and the structures needed to be blocked for beam transmission in the vicinity. For each case, two treatment plans were optimized: one using the MLC and one using the IRIS-collimator providing variable circular fields. Plan re-quirements were: dose prescription to the 70% isodose line (18 or 20Gy), 100% GTV coverage, ≥98% PTV coverage, undisturbed central high dose region (95% of maximum dose) and a conformity index as low as possible. Plan com-parison parameters were: conformity index (CI), high-dose gradient index (GIH), low-dose gradient index (GIL), total number of monitor units (MU) and expected treatment time (TT). For all cases, clinically acceptable plans could be gen-erated with the following results (mean±SD) for CI, GIH, GIL, MU and TT, respectively for the MLC plans: 1.09±0.03, 2.77±0.26, 2.61±0.08, 4514±830MU and 27±5min and for the IRIS plans: 1.05±0.01, 3.00±0.35, 2.46±0.08, 8557±1335MU and 42±7min. In summary, the MLC plans were on average less conformal and had a shallower dose gradient in the low dose region, but a steeper dose gradient in the high dose region. This is accompanied by a smaller vol-ume receiving 10Gy. A plan by plan comparison shows that usage of the MLC can spare about one half of the MUs and one third of treatment time. From these experiences and results suggestions for MLC planning strategy can be de-duced.

scholarly journals The Dosimetric and Temporal Effects of Respiratory-Gated, High-Dose-Rate Radiation Therapy in Patients With Lung Cancer

2018 ◽  
Vol 18 ◽  
pp. 153303381881607 ◽  
Author(s):  
Ouided Rouabhi ◽  
Brandie Gross ◽  
John Bayouth ◽  
Junyi Xia
Keyword(s):  
Lung Cancer ◽  
Radiation Therapy ◽  
Dose Rate ◽  
Treatment Time ◽  
High Dose Rate ◽  
High Dose ◽  
Lung Dose ◽  
Treatment Delivery ◽  
Treatment Plans ◽  
Mean Lung Dose

Purpose: To evaluate the dosimetric and temporal effects of high-dose-rate respiratory-gated radiation therapy in patients with lung cancer. Methods: Treatment plans from 5 patients with lung cancer (3 nongated and 2 gated at 80EX-80IN) were retrospectively evaluated. Prescription dose for these patients varied from 8 to 18 Gy/fraction with 3 to 5 treatment fractions. Using the same treatment planning criteria, 4 new treatment plans, corresponding to 4 gating windows (20EX-20IN, 40EX-40IN, 60EX-60IN, and 80EX-80IN), were generated for each patient. Mean tumor dose, mean lung dose, and lung V20 were used to assess the dosimetric effects. A MATLAB algorithm was developed to compute treatment time. Results: Mean lung dose and lung V20 were on average reduced between −16.1% to −6.0% and −20.0% to −7.2%, respectively, for gated plans when compared to the corresponding nongated plans, and between −5.8% to −4.2% and −7.0% to −5.4%, respectively, for plans with smaller gating windows when compared to the corresponding plans gated at 80EX-80IN. Treatment delivery times of gated plans using high-dose rate were reduced on average between −19.7% (−0.10 min/100 MU) and −27.2% (−0.13 min/100 MU) for original nongated plans and −15.6% (−0.15 min/100 MU) and −20.3% (−0.19 min/100 MU) for original 80EX-80IN-gated plans. Conclusion: Respiratory-gated radiation therapy in patients with lung cancer can reduce lung dose while maintaining tumor dose. Because treatment delivery during gated therapy is discontinuous, total treatment time may be prolonged. However, this increase in treatment time can be offset by increasing the dose delivery rate. Estimation of treatment time may be helpful in selecting patients for respiratory gating and choosing appropriate gating windows.

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

2021 ◽  
pp. 1-8
Author(s):  
Sin Ting Chiu ◽  
Po Man Wu ◽  
Ka Fai Cheng ◽  
Pui Hei Fok ◽  
George Chiu
Keyword(s):  
Breast Cancer ◽  
Treatment Time ◽  
Organs At Risk ◽  
Statistical Significance ◽  
Left Lung ◽  
Delivery Time ◽  
Plan Quality ◽  
Nodal Involvement ◽  
Treatment Delivery ◽  
Supraclavicular Fossa

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.

3D conformal, IMRT and VMAT for the treatment of head and neck cancer: a brief literature review

2020 ◽  
pp. 1-4
Author(s):  
Kazi T. Afrin ◽  
Salahuddin Ahmad
Keyword(s):  
Radiation Therapy ◽  
Head And Neck Cancer ◽  
Literature Review ◽  
Head And Neck ◽  
Neck Cancer ◽  
Treatment Time ◽  
Organs At Risk ◽  
Patient Comfort ◽  
High Dose ◽  
3D Crt

Abstract Aim: The objective of this study has been to identify monitor unit (MU) and treatment time variations, volume coverage dissimilarity among 3D conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) treatment plans for head and neck cancer (HNC) based on literature review. Methods: A number of HNC cases were studied with the investigation of conformity and homogeneity index. Results: When high-dose modulation was required around small organs at risk (OARs), a clinically acceptable IMRT plan was achieved as VMAT usually required longer dose optimisation time. The greatest benefit of VMAT has been rapid treatment delivery allowing improved patient comfort, reduced intra-fraction motion and increased patient throughput. In some papers, 3D-CRT was shown not to meet well the requirements on parotid glands. One paper showed that cerebellum dose was lower for 3D-CRT than IMRT. However, it was found in other papers that OAR sparing with 3D-CRT was reasonable but in complex cases not enough. Conclusions: IMRT usually consists of several treatment fields with different directions, hundreds of beam lets with modulated intensity, an advantage over 3D-CRT, whereas VMAT has advantage over IMRT due to rotating beam utilisation. VMAT has lower total MU and treatment times than IMRT and 3D-CRT, while maintaining similar dosimetric endpoints.

scholarly journals Dosimetric comparison and TCP-NTCP modelling for lung, heart, left anterior descending and right coronary artery in left sided breast cancer conventional and hypofractionated radiotherapy

2021 ◽  
Author(s):  
Hossein Taheri ◽  
Ali Akhavan ◽  
Mohammadbagher Tavakoli ◽  
Reza Moghareabed ◽  
Mahsa Kianinia
Keyword(s):  
Breast Cancer ◽  
Treatment Time ◽  
Good Alternative ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Breast Cancer Patients ◽  
Ipsilateral Lung ◽  
Internal Mammary ◽  
Ct Simulation ◽  
3D Crt

Abstract BackgroundThe aim of this study was to evaluate the dose distribution, and also tumor control probability (TCP) and normal tissue complications probability (NTCP) models of left sided breast cancer females for 3D-CRT, 6 and 9 fields IMRT and hypofractionated tangential plans.MethodsSixty left sided breast cancer females were included in this study. CT simulation images of the patients were imported on the treatment planning software (TiGRT, LinaTech, China), and the tangential treatment plans of the mentioned methods were done for each patient. The dosimetric evaluation, and TCP-NTCP models of stated modalities were done using Poisson Linear-Quadatric (PLQ) and Lyman-Kutcher-Burman (LKB) models on the MATLAB and R softwares.ResultsThe mean (± SD) dose to ipsilateral lung, heart, LAD and RCA with/without internal mammary fields for 6FIMRT was lower compared to other modalities. Furthermore, V20Gy for Ipsilateral lung and V25Gy for heart, LAD and RCA of 6FIMRT was lower than other methods. In addition, the PTV dose coverage was higher for 9FIMRT and hypofractionated RT, while it may be lower for 3D-CRT among the studied methods. Although TCP values of 9 and 6fieds and hypofractionated was not significantly different, the TCPs of them were higher compared to 3D-CRT. However, the NTCP for ipsilateral lung, heart, LAD and RCA of 6FIMRT was lower than others.Conclusion6FIMRT is suitable choice for RT of breast cancer patients compared to other mentioned modalities, as a result of providing adequate PTV dose coverage and TCP, and also lower imposed dose and NTCP for OARs. Hypofractionated RT is a good alternative to reduce treatment time for the breast cancer patients.Trial registrationThis study was approved by the ethical board of Isfahan University of Medical Sciences, Isfahan, Iran (IR.MUI.MED.REC.1399.677).

scholarly journals Impact of CBCT frequency on target coverage and dose to the organs at risk in adjuvant breast cancer radiotherapy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kai J. Borm ◽  
Yannis Junker ◽  
Mathias Düsberg ◽  
Michal Devečka ◽  
Stefan Münch ◽  
...  
Keyword(s):  
Breast Cancer ◽  
At Risk ◽  
Dose Distribution ◽  
Organs At Risk ◽  
Breast Cancer Patients ◽  
Cancer Radiotherapy ◽  
Breast Cancer Radiotherapy ◽  
Target Volumes ◽  
Adjuvant Breast Cancer ◽  
Delivered Dose

AbstractThe current study aims to assess the effect of cone beam computed tomography (CBCT) frequency during adjuvant breast cancer radiotherapy with simultaneous integrated boost (SIB) on target volume coverage and dose to the organs at risk (OAR). 50 breast cancer patients receiving either non-hypofractionated or hypofractionated radiotherapy after lumpectomy including a SIB to the tumor bed were selected for this study. All patients were treated in volumetric modulated arc therapy (VMAT) technique and underwent daily CBCT imaging. In order to estimate the delivered dose during the treatment, the applied fraction doses were recalculated on daily CBCT scans and accumulated using deformable image registration. Based on a total of 2440 dose recalculations, dose coverage in the clinical target volumes (CTV) and OAR was compared depending on the CBCT frequency. The estimated delivered dose (V95%) for breast-CTV and SIB-CTV was significantly lower than the planned dose distribution, irrespective of the CBCT-frequency. Between daily CBCT and CBCT on alternate days, no significant dose differences were found regarding V95% for both, breast-CTV and SIB-CTV. Dose distribution in the OAR was similar for both imaging protocols. Weekly CBCT though led to a significant decrease in dose coverage compared to daily CBCT and a small but significant dose increase in most OAR. Daily CBCT imaging might not be necessary to ensure adequate dose coverage in the target volumes while efficiently sparing the OAR during adjuvant breast cancer radiotherapy with SIB.

scholarly journals Cervical cancer brachytherapy amid the COVID-19 pandemic: A single institutional case series

2021 ◽  
Author(s):  
Zahra Siavashpour ◽  
Mahdi Aghili ◽  
Ramin Jaberi ◽  
Anya Jafari ◽  
Fatemeh Jafari
Keyword(s):  
Cervical Cancer ◽  
Treatment Time ◽  
Organs At Risk ◽  
Locally Advanced ◽  
Case Series ◽  
Target Volume ◽  
High Dose Rate ◽  
High Dose ◽  
Overall Treatment Time ◽  
Dose Constraints

Dose escalation to target volume during High Dose Rate brachytherapy was effectively employed to treat locally advanced cervical cancer patients who experienced prolongation of overall treatment time (OTT) due to the COVID-19 pandemic. It was tried to achieve acceptable oncological outcomesو while respecting the dose constraints of organs at risk.

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