Radiation-induced biological changes of neural structures in the base of the skull tumours

2017 ◽  
Vol 16 (2) ◽  
pp. 183-198
Author(s):  
C. Gh. Buzea ◽  
C. Mirestean ◽  
Irina Butuc ◽  
A. Zara ◽  
D. T. Iancu
Keyword(s):  
Normal Tissue ◽  
Volumetric Modulated Arc Therapy ◽  
Nasopharyngeal Cancer ◽  
Conformal Radiotherapy ◽  
Planning System ◽  
Conformity Index ◽  
Delivery Times ◽  
Brain Radionecrosis ◽  
The Mean ◽  
3D Crt

AbstractBackground and purposeThe aim of this paper is to compare neural induced changes in three-dimensional conformal radiotherapy (3D-CRT) versus intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for nasopharyngeal cancers.Materials and methodsRadiotherapy plans for 10 patients with nasopharyngeal cancer stages III and IV were prospectively developed for 3D-CRT, IMRT and VMAT using Varian Eclipse planning system. The same radiation therapist carried out all planning and the same clinical dosimetric constraints were used. Normal tissue complication probabilities were calculated.ResultsThe mean planning target volume’s (PTVs) conformity index (CI) for 3D-CRT was 1·424, for IMRT 1·1, and for VMAT 1·081. The PTV homogeneity (HI) index was 0·204 for 3D-CRT, 0·124 for IMRT and 0·153 for VMAT. Normal tissue complication probabilities gave complex results for 3D-CRT, IMRT and VMAT and are analysed in detail in this paper. The mean monitor units were 95 (range 9–180) for 3D-CRT; 165 (range 52–277) for IMRT; and 331 (range 167–494) for VMAT (p<0·05).ConclusionsVMAT is associated with similar dosimetric advantages as IMRT over 3D-CRT for nasopharyngeal cancer. VMAT is associated with faster delivery times and greater number of mean monitor units than IMRT. Brain radionecrosis severity and risk, in the past, have been underestimated. By improving the life expectancy of patients with nasopharyngeal cancer to ensure maintenance of the neural structures, recommended dose limits should be considered as a first degree priority (as the spinal cord, brainstem, etc.) when IMRT and VMAT plans are implemented.

Dosimetric comparison of 3-dimensional conformal radiotherapy (3D-CRT) and volumetric-modulated arc therapy (VMAT) in locally advanced cancer cervix

2020 ◽  
pp. 1-8
Author(s):  
Animesh Agrawal ◽  
Rahat Hadi ◽  
Satyajeet Rath ◽  
Avinav Bharati ◽  
Madhup Rastogi ◽  
...  
Keyword(s):  
De Novo ◽  
Abdominal Cavity ◽  
Locally Advanced ◽  
Volumetric Modulated Arc Therapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Conformity Index ◽  
Dosimetric Comparison ◽  
Arc Therapy ◽  
3D Crt

Abstract Introduction: Dosimetric advantages of volumetric-modulated arc therapy (VMAT) over three-dimensional conformal radiotherapy (3D-CRT) are not established in a head-on comparison of a uniform group of locally advanced carcinoma of the cervix (LACC). Therefore, we conducted a dosimetric comparison of these two techniques in LACC patients. Materials and methods: Computed tomography (CT) data of histologically proven de novo LACC, including Stage IIB–IIIB and earlier stages deemed inoperable, were included in this prospective observational dosimetric study. Planning was initially done by 3D-CRT technique (dose of 45–50·4 Gy @ 1·8–2 Gy/# was used in the actual treatment), followed by VMAT planning and appropriate dosimetric comparisons were done in 39 cases. Results: For planning target volume coverage, D95, D98 and D100 (p < 0·0001 for all parameters) and V95 and V100 (p = 0·002 and <0·0001, respectively) were significantly improved with VMAT. The conformity index (CI) was significantly better with VMAT (p = 0·03), while 3D-CRT had a significantly better homogeneity index (HI)(p = 0·003). Dose to the urinary bladder was significantly reduced with VMAT compared to 3D-CRT for V20–V50, except V10. The doses to the rectum and abdominal cavity were significantly reduced with VMAT compared to 3D-CRT plans for all parameters (V10–V50). The number of organs at risks (OARs) for which constraints were met was higher with VMAT plans than with 3D-CRT plans, with at least four out of the five OARs protected in 46·1 versus 5·1% and all constraints achieved in 15·4% versus none. Conclusion: We conclude that in dosimetric terms, VMAT is superior to 3D-CRT for LACC.

DOSIMETRIC COMPARISON OF VMAT AND 3D CONFORMAL RADIOTHERAPY IN PREOPERATIVE RECTAL CANCER

2021 ◽  
Author(s):  
Tatjana Miladinović ◽  
◽  
Aleksandar Miladinović ◽  
Nina Pavlović ◽  
Dragoslav Nikezić ◽  
...  
Keyword(s):  
Femoral Head ◽  
Treatment Planning ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Conformity Index ◽  
Rectum Cancer ◽  
Clockwise Direction ◽  
3D Crt

The standard procedure in treating rectum cancer is surgical intervention, but presurgical chemotherapy and radiotherapy lead to a lower rate of localized recidives. Our study compared the results obtained by two techniques of radiation treatment planning (RTP) in radiotherapy, which patients received in the preoperative course of rectum cancer treatment, Volumetric Modulated Arc Therapy (VMAT) and field-in-field three-dimensional conformal radiotherapy (FIF 3D-CRT). We analyzed better coverage of the planning target volume (PTV) and better protection of organs from risk (OAR): bladder, bowel, left femoral head, and right femoral head results and monitor unit (MU). Also, we analyzed the target volume coverage indicators included homogeneity index (HI), and conformity index (CI). Selected five patients were treated in University Clinical Center Kragujevac during 2020. The two types of techniques for making radiotherapy plans, mentioned above, were designed for each patient using the same CT scans. All plans were done on the treatment planning system ECLIPSE- Version 15.6 (Varian). The prescribed dose for all patients was 50 Gy in 25 fractions. The first arc was planned in the clockwise direction and the second in the counter clockwise direction. FIF 3D-CRT plans were obtained by using fields from four different directions with the same isocenter. It was obtained that VMAT plans, compared to the FIF 3D-CRT, achieved better coverage of the PTV (D95%), better heterogeneity, and conformity. Protection for OAR such as the bladder, femoral heads, and small bowel is much better than that given by FIF 3D-CRT plans. However, the number of MU calculated by FIF 3D-CRT is almost twice lower compared to VMAT.

scholarly journals A Dosimetric Analysis of Reduction Cardiac Dose with Lead Shielding in Breast Cancer Radiotherapy

2021 ◽  
Vol 11 (20) ◽  
pp. 9686
Author(s):  
Hsiao-Wen Chiu ◽  
Lu-Han Lai ◽  
Chien-Yi Ting
Keyword(s):  
Heart Diseases ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Conformal Radiotherapy ◽  
Left Breast ◽  
Conformity Index ◽  
Target Area ◽  
Heart Dose ◽  
Breast Cancer Radiotherapy ◽  
3D Crt

Adjuvant radiotherapy is an important treatment modality after breast-conserving surgery. Due to its proximity, radiation therapy for the left breast can often lead to an escalated heart dose that can result in heart diseases. The purpose of this study was to evaluate the heart dose reduction by using lead shields surrounding the left breast. The doses of a 3D conformal radiotherapy (3D-CRT) plan, an intensity-modulated radiotherapy (IMRT) plan, and volumetric-modulated arc therapy (VMAT) to the left breast tumor in a CIRS ATOM anthropomorphic female adult phantom were measured by optically stimulated luminescence dosimeters (OSLDs). To protect critical organs, the skin around the target area was covered by lead shields of two different thicknesses (0.125 mm and 0.25 mm). The results showed that compared to IMRT and 3D-CRT, VMAT provided better planning target volume (PTV) coverage, a better conformity index (CI), and homogeneity index (HI). With the use of lead shields, the thyroid dose was reduced by 5.12–27.5% and 20.51–30%, respectively; the heart dose was reduced by 49.41–50.12% and 56.38–57.42%, respectively; and the lung dose was reduced by 1.23–45.22% and 0.98–57.83%, respectively. Although the clinical application of lead shields was rare, this study verified that it could effectively decrease the heart dose from 4.31 ± 0.09 Gy to 1.88–2.18 Gy, thereby potentially reducing the risk of associated heart diseases by 14.8%. Further works to implement this method into clinical practice are needed.

scholarly journals A COMPARATIVE DOSIMETRIC STUDY OF LEFT SIDED BREAST CANCER AFTER BREAST CONSERVING SURGERY WITH 3D-CRT AND VMAT

2020 ◽  
Vol 8 (11) ◽  
pp. 1088-1093
Author(s):  
F. Kouhen ◽  
◽  
H.El Gouache ◽  
M. Bensediq ◽  
K. Saadi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Volumetric Modulated Arc Therapy ◽  
Three Dimensional ◽  
Conformal Radiotherapy ◽  
Breast Conserving Surgery ◽  
Left Breast ◽  
Conformity Index ◽  
Clinical Value ◽  
Three Dimensional Conformal Radiotherapy ◽  
3D Crt

Purpose: This paper aims to compare dosimetric differences based between three-dimensional conformal radiotherapy (3D-CRT), and volumetric modulated arc therapy(VMAT) techniques of radiotherapy plans for postoperative left breast cancer after breast conserving surgery. Materials and Methods: Nineteen patients with left breast cancer who had received breast conserving surgery without nodal involvement. Two separate treatment plans with an identical isocenter were created to each patient: 3D radiotherapy plan with 2 tangent isocentric beams with field-in-field technique andVMAT plan with Two duplicate sets of partial arcs. Results: The VMAT plan showed superior to PTV dose conformity index (CI), homogeneity index (HI), protection of the ipsilateral lung, and heart compared with 3D plan. However, it increases significantly dose to the contralateral breast with D mean which were 0.1±0.003 Gy and 5.31±1.04 Gy, respectively. Conclusion: VMAT greatly decreases the radiation doses delivered to the OAR with maintained therapeutic efficacy.However, further studies evaluating the clinical outcome of treatments are needed to proof the clinical value of this radiation technique.

scholarly journals Treatment planning comparison of volumetric modulated arc therapy with Trilogy and Halcyon for bilateral breast cancer

2021 ◽  
Author(s):  
Tao Sun ◽  
Xiutong Lin ◽  
Guifang Zhang ◽  
Qingtao Qiu ◽  
Chengqiang Li ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Treatment Planning ◽  
Volumetric Modulated Arc Therapy ◽  
Bilateral Breast Cancer ◽  
Planning System ◽  
Skin Dose ◽  
Delivery Time ◽  
Dose Volume ◽  
Arc Therapy ◽  
The Mean

Abstract Background: The Halcyon is a new machine from the Varian company. The purpose of this study was to evaluate the dosimetry of the Halcyon in treatment of bilateral breast cancer with volumetric modulated arc therapy. Methods: On CT images of 10 patients with bilateral breast cancer, four Halcyon plans with different setup fields were generated, and dosimetric comparisons using Bonferroni’s multiple comparisons test were conducted among the four plans. Whole and partial arc plans on the Trilogy and the Halcyon, referred to as T-4arc, T-8arc, H-4arc and H-8arc, were designed. The prescription dose was 50 Gy in 2-Gy fractions. All plans were designed with the Eclipse version 15.5 treatment planning system. The dosimetric differences between whole and partial arc plans in the same accelerator were compared using the Mann-Whitney U test. The better Halcyon plan was selected for the further dosimetric comparison of the plan quality and delivery efficiency between the Trilogy and the Halcyon. Results:Halcyon plans with high‐quality megavoltage cone beam CT setup fields increased the Dmean, D2 and V107 of the planning target volume (PTV) and the V5 and Dmean of the heart, left ventricle (LV) and lungs compared with other Halcyon setup plans. The mean dose and low dose volume of the heart, lungs and liver were significantly decreased in T-8arc plans compared to T-4arc plans. In terms of the V5, V20, V30, V40 and Dmean of the heart, the V20, V30, V40 and Dmean of the LV, the V30, V40, Dmax and Dmean of the left anterior descending artery (LAD), and the V5 and V40 of lungs, H-8arc was significantly higher than H-4arc (p<0.05). Compared with the Trilogy’s plans, the Halcyon’s plans reduced the high-dose volume of the heart and LV but increased the mean dose of the heart. For the dose of the LAD and the V20 and V30 of lungs, there was no significant difference between the two accelerators. Compared with the Trilogy, plans on the Halcyon significantly increased the skin dose but also significantly reduced the delivery time. Conclusion: For the Halcyon, the whole-arc plans have more dosimetric advantages than partial-arc plans in bilateral breast cancer radiotherapy. Although the mean dose of the heart and the skin dose are increased, the doses of the cardiac substructure and other OARs are comparable to the Trilogy, and the delivery time is significantly reduced.

scholarly journals Treatment planning comparison of volumetric modulated arc therapy with the trilogy and the Halcyon for bilateral breast cancer

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Tao Sun ◽  
Xiutong Lin ◽  
Guifang Zhang ◽  
Qingtao Qiu ◽  
Chengqiang Li ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Treatment Planning ◽  
Volumetric Modulated Arc Therapy ◽  
Bilateral Breast Cancer ◽  
Planning System ◽  
Skin Dose ◽  
Delivery Time ◽  
Dose Volume ◽  
Arc Therapy ◽  
The Mean

Abstract Background The Halcyon is a new machine from the Varian company. The purpose of this study was to evaluate the dosimetry of the Halcyon in treatment of bilateral breast cancer with volumetric modulated arc therapy. Methods On CT images of 10 patients with bilateral breast cancer, four Halcyon plans with different setup fields were generated, and dosimetric comparisons using Bonferroni’s multiple comparisons test were conducted among the four plans. Whole and partial arc plans on the Trilogy and the Halcyon, referred to as T-4arc, T-8arc, H-4arc and H-8arc, were designed. The prescription dose was 50 Gy in 2-Gy fractions. All plans were designed with the Eclipse version 15.5 treatment planning system. The dosimetric differences between whole and partial arc plans in the same accelerator were compared using the Mann–Whitney U test. The better Halcyon plan was selected for the further dosimetric comparison of the plan quality and delivery efficiency between the Trilogy and the Halcyon. Results Halcyon plans with high‐quality megavoltage cone beam CT setup fields increased the Dmean, D2 and V107 of the planning target volume (PTV) and the V5 and Dmean of the heart, left ventricle (LV) and lungs compared with other Halcyon setup plans. The mean dose and low dose volume of the heart, lungs and liver were significantly decreased in T-8arc plans compared to T-4arc plans. In terms of the V5, V20, V30, V40 and Dmean of the heart, the V20, V30, V40 and Dmean of the LV, the V30, V40, Dmax and Dmean of the left anterior descending artery (LAD), and the V5 and V40 of lungs, H-8arc was significantly higher than H-4arc (p < 0.05). Compared with the Trilogy’s plans, the Halcyon’s plans reduced the high-dose volume of the heart and LV but increased the mean dose of the heart. For the dose of the LAD and the V20 and V30 of lungs, there was no significant difference between the two accelerators. Compared with the Trilogy, plans on the Halcyon significantly increased the skin dose but also significantly reduced the delivery time. Conclusion For the Halcyon, the whole-arc plans have more dosimetric advantages than partial-arc plans in bilateral breast cancer radiotherapy. Although the mean dose of the heart and the skin dose are increased, the doses of the cardiac substructure and other OARs are comparable to the Trilogy, and the delivery time is significantly reduced.

scholarly journals Non-coplanar volumetric modulated arc therapy for locoregional radiotherapy of left-sided breast cancer including internal mammary nodes

2021 ◽  
Vol 55 (4) ◽  
pp. 499-507
Author(s):  
Yuan Xu ◽  
Pan Ma ◽  
Zhihui Hu ◽  
Yuan Tian ◽  
Kuo Men ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Coronary Artery ◽  
Volumetric Modulated Arc Therapy ◽  
Left Lung ◽  
Target Volume ◽  
Conformity Index ◽  
Internal Mammary Nodes ◽  
Arc Therapy ◽  
Internal Mammary ◽  
The Mean

Abstract Background Non-coplanar volumetric modulated arc therapy (ncVMAT) is proposed to reduce toxicity in heart and lungs for locoregional radiotherapy of left-sided breast cancer, including internal mammary nodes (IMN). Patients and methods This retrospective study included 10 patients with left-sided breast cancer who underwent locoregional radiotherapy after breast-conserving surgery. For each patient, the ncVMAT plan was designed with four partial arcs comprising two coplanar arcs and two non-coplanar arcs, with a couch rotating to 90°. The prescribed dose was normalized to cover 95% of planning target volume (PTV), with 50 Gy delivered in 25 fractions. For each ncVMAT plan, dosimetric parameters were compared with the coplanar volumetric modulated arc therapy (coV-MAT) plan. Results T here were improvements in conformity index, homogeneity index and V55 of total target volume (PTVall) comparing ncVMAT to coVMAT (p < 0.001). Among the organs at risk, the average V30, V20, V10, V5, and mean dose (Dmean) of the heart decreased significantly (p < 0.001). Furthermore, ncVMAT significantly reduced the mean V20, V10, V5, and Dmean of left lung and the mean V10 and V5 and Dmean of contralateral lung (p < 0.001). An improved sparing of the left anterior descending coronary artery and right breast were also observed with ncVMAT (p < 0.001). Conclusions Compared to coVMAT, ncVMAT provides improved conformity and homogeneity of whole P TV, better dose sparing of the heart, bilateral lungs, left anterior descending coronary artery (LAD), and right breast for locoregional radiotherapy of left-sided breast cancer with IMN, potentially reducing the risk of normal tissue damage.

A Novel Conformal Arc Technique for Postoperative Whole Pelvic Radiotherapy for Endometrial Cancer

2009 ◽  
Vol 19 (9) ◽  
pp. 1574-1579 ◽  
Author(s):  
Ruijie Yang ◽  
Weijuan Jiang ◽  
Junjie Wang
Keyword(s):  
Endometrial Cancer ◽  
Intensity Modulated Radiation Therapy ◽  
Dose Intensity ◽  
Conformal Radiotherapy ◽  
Pelvic Bone ◽  
Pelvic Radiotherapy ◽  
3 Dimensional ◽  
Dose Uniformity ◽  
The Mean ◽  
3D Crt

Introduction:Conventional whole pelvic radiotherapy (WPRT) with 3-dimensional conformal radiotherapy (3D-CRT) exposes most of the contents of the true pelvis to the prescribed dose. Intensity-modulated radiation therapy (IMRT) provides more conformal dose distribution and better sparing of critical structures for WPRT. However, IMRT is more complicated in planning and delivery, requiring more expensive equipment and time-consuming quality assurance. We explore and evaluate a novel conformal arc radiotherapeutic technique for postoperative WPRT for endometrial cancer in this study.Methods:This technique involves 2-axis conformal arc therapy (2A-CAT) with 180-degree rotation around 2 isocenters each in 2 separate dose-shaping structures. Dosimetric comparison with 3D-CRT and IMRT for 10 endometrial cancer patients undergoing postoperative WPRT was performed to evaluate this new 2A-CAT technique.Results:The mean conformity indices were 0.83, 0.61, and 0.88 for 2A-CAT, 3D-CRT, and IMRT, respectively. The mean homogeneity indices were 1.15, 1.08, and 1.10. The mean doses to bowel, rectum, bladder, and pelvic bone marrow were, respectively, 1.19, 3.39, 4.65, and 1.64 Gy lower with 2A-CAT than with 3D-CRT (P < 0.05), whereas a little higher than with IMRT. The mean dose to normal tissue was 1.87 Gy higher with 2A-CAT than with IMRT (P = 0.00).Conclusions:In postoperative WPRT for endometrial cancer, 2A-CAT significantly improves the dose conformity and sparing of bowel, rectum, and bladder compared with 3D-CRT. Despite dose uniformity and conformity being still inferior to those of IMRT, its simplicity and extensive availability combined with further improvement warrant it as a potential shortcut alternative to IMRT.

Sign in / Sign up

Export Citation Format

Share Document