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.

scholarly journals Preliminary Simulation Study of Carotid Artery and Pharyngeal Constrictor Muscle Sparing-Radiotherapy in Glottic Carcinoma

2020 ◽  
Vol 19 ◽  
pp. 153303382095698
Author(s):  
Yurday Ozdemir ◽  
Ibrahim Acibuci ◽  
Ugur Selek ◽  
Erkan Topkan
Keyword(s):  
Simulation Study ◽  
Intensity Modulated Radiotherapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Glottic Carcinoma ◽  
3 Dimensional ◽  
Constrictor Muscle ◽  
The Mean ◽  
The Right ◽  
3D Crt

Background: This preliminary simulation study aimed to compare the dosimetric outcomes of carotid arteries (CAs) and pharyngeal constrictor muscle (PCM) in patients with T1N0M0 glottic carcinoma undergoing helical tomotherapy-intensity modulated radiotherapy (HT-IMRT) and 3-dimensional conformal radiotherapy (3D-CRT) plans. Methods: In addition to the clinical target volume (CTV) which was defined as the entire larynx, the CAs and PCM of 11 glottic carcinoma patients were delineated. The CTV was uniformly expanded 5 mm to create a planning target volume (PTV) relative to the PCM and at a distance of 2 mm from the CA. The dosimetric characteristics in HT-IMRT and lateral opposed fields-based 3D-CRT plans were analyzed. Results: Median D95%and V100% of PTV were significantly higher in HT-IMRT (p < 0.001) compared to 3D-CRT. The right/left CA dosimetric outcomes, including the mean doses (20.7/21.5 Gy versus 48.7/50.5 Gy), Dmax (53.6/52.0 Gy versus 67.4/67.7 Gy), V30 (25.0/27.1% versus 77.6/80.3%), V40 (8.0/7.9% versus 74.6/71.9%), and V50 (2.0/1.2% versus 70.0/71.6%) were also significantly lower in HT-IMRT (p < 0.05), similar to the mean PCM doses (49.6 Gy versus 62.6 Gy for 3D-CRT;p < 0.001), respectively. Conclusions: Our present results demonstrated the feasibility of simultaneous sparing of the CAs and PCM in HT-IMRT- compared to 3D-CRT plans in glottic carcinoma patients undergoing definitive radiotherapy.

scholarly journals Peripheral blood lymphocyte counts during standard conformal radiotherapy and TomoTherapy/IMRT for prostate cancer

2008 ◽  
Vol 7 (4) ◽  
pp. 223-227 ◽  
Author(s):  
M. Elsworthy ◽  
P.N. Plowman
Keyword(s):  
Peripheral Blood Lymphocyte ◽  
Peripheral Blood ◽  
Blood Lymphocyte ◽  
Small Volume ◽  
Intensity Modulated Radiation Therapy ◽  
Conformal Radiotherapy ◽  
Peripheral Lymphocyte ◽  
Prostate Radiotherapy ◽  
The Mean ◽  
Lymphocyte Populations

AbstractLymphopaenia is the earliest and the most sensitive routinely assessed biological parameter of corporeal radiation exposure in clinical practice; bone marrow, lymph nodes and peripheral blood lymphocyte populations are also at risk. During radical prostate radiotherapy, in 28 patients, the mean peripheral lymphocyte count fell from 1.76 × 109/l (standard deviation (SD) 0.63, 95% confidence interval (conf.) 0.23) to 1.10 × 109/l (SD 0.38, conf. 0.14), (p < 0.05). The question was asked as to whether intensity-modulated radiation therapy (IMRT) by TomoTherapy would cause more lymphopaenia than three-field conformal radiotherapy, bearing in mind the ‘low dose bath’ effect of IMRT and the long ‘beam-on’ times. Thirteen patients receiving three-field conformal radiotherapy experienced a fall in peripheral lymphocyte counts from 2.02 (SD: 0.62. conf. 0.43) to 1.17 × 109/l (SD: 0.47, conf. 0.26) after 34–38 Gy, as compared to a fall from 1.6 × 109/l (SD: 0.6, conf. 0.35) to 1.04 × 109/l (SD: 0.3, conf. 0.15) for 15 TomoTherapy patients—non-significant differences. We conclude that for this (approximately) standard, small-volume pelvic radiotherapy and to the dose under scrutiny, we cannot detect differences between the two radiotherapy techniques in terms of the lymphopaenia accruing. Neutrophil counts were similarly non-significantly different.

Dosimetric study of 3-dimensional conformal radiotherapy, electronic compensator technique, intensity modulated radiation therapy, and volumetric arc therapy in whole-breast irradiation.

2015 ◽  
Vol 33 (28_suppl) ◽  
pp. 44-44
Author(s):  
Chonnipa Nantavithya
Keyword(s):  
Intensity Modulated Radiation Therapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Contralateral Breast ◽  
Breast Irradiation ◽  
Lung Dose ◽  
Volumetric Arc Therapy ◽  
Arc Therapy ◽  
Ct Simulation ◽  
3D Crt

44 Background: Whole breast irradiation is an essential treatment after breast conserving surgery (BCS). Adverse effects are from inhomogeneity of PTV and excessive dose to normal tissues. Aim of this study is to compare dosimetry among standard technique, three-dimensional Conformal Radiotherapy (3D-CRT) and advanced techniques, Electronic Compensator (ECOMP), Intensity Modulated Radiation Therapy (IMRT) and Volumetric Arc Therapy (VMAT). Methods: Images from CT simulation of patients who underwent BCS were replanned. Clinical Target Volume (CTV) was contoured followed RTOG atlas as breast only and breast with chest wall respectively. Planning Target Volume (PTV) was expanded 0.7 cm from CTV. Each patient was replanned with all four techniques. Dose prescription was 50 Gy in 25 fractions. Results: Twenty five patients underwent CT simulation from November 2013 to November 2014 were included. Six patients with node positive were planned for breast with chest wall irradiation and 19 patients with node negative were planned for breast only irradiation. Primary outcome, homogeneity index (HI) of 3D-CRT, ECOMP, IMRT and VMAT were 0.865, 0.889, 0.890 and 0.866 respectively which ECOMP and IMRT were significant higher than 3D-CRT (p values < 0.001). Secondary outcome, conformity index (CI), Mean heart dose (MHD), heart V25, heart V30, mean lung dose (MLD), mean ipsilaterallung dose (MILD), mean contralateral lung dose (MCLD) and mean contralateral breast dose (MCBD) of advanced techniques were significant better than 3D-CRT technique. Conclusions: HI of ECOMP and IMRT were statistically significant higher compared with 3D-CRT technique. Advanced techniques showed statistically significant superior in CI dose to heart, lungs and contralateral breast.

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.

scholarly journals Outcomes after intensity-modulated compared with 3-dimensional conformal radiotherapy with chemotherapy for squamous cell carcinoma of the anal canal

2019 ◽  
Vol 26 (4) ◽  
Author(s):  
M. S. Agarwal ◽  
K. E. Hitchcock ◽  
C. G. Morris ◽  
T. J. George Jr ◽  
W. M. Mendenhall ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Anal Canal ◽  
Cell Carcinoma ◽  
Conformal Radiotherapy ◽  
Concurrent Chemotherapy ◽  
Free Survival ◽  
3 Dimensional ◽  
Intensity Modulated ◽  
Anal Canal Carcinoma ◽  
3D Crt

Purpose   We report our institution’s treatment techniques, disease outcomes, and complication rates after radiotherapy for the management of anal canal carcinoma with intensity-modulated radiotherapy (imrt) and concurrent chemotherapy relative to prior cases managed with 3-dimensional conformal radiotherapy (3D-crt).Methods   In a retrospective review of the medical records of 21 patients diagnosed with biopsy-proven stage i (23%), stage ii (27%), or stage iii (50%) squamous-cell carcinoma of the anal canal treated with curative chemotherapy and imrt between July 2009 and December 2014, patient outcomes were determined. Results for patients treated with 3D-crt by the same group were previously reported. The median initial radiation dose to the pelvic and inguinal nodes at risk was 45 Gy (range: 36–50.4 Gy), and the median total dose, including local anal canal primary tumour boost, was 59.4 Gy (range: 41.4–61.2 Gy). Patients received those doses over a median of 32 fractions (range: 23–34 fractions). Chemotherapy consisted of 2 cycles of concurrent fluorouracil–cisplatin (45%) or fluorouracil–mitomycin C (55%).Results   Median follow-up was 3.1 years (range: 0.38–6.4 years). The mean includes a patient who died of septic shock at 38 days. The 3-year rates of overall survival, metastasis-free survival, locoregional control, and colostomy-freesurvival were 95%, 100%, 100%, and 100% respectively. No patients underwent abdominoperitoneal resection after chemoradiotherapy or required diverting colostomy during or after treatment. Those outcomes compare favourably with the previously published series that used 3D-crt with or without brachytherapy in treating anal canal cancers. Of the 21 patients in the present series, 10 (48%) experienced acute grade 3, 4, or 5 toxicities related to treatment.Conclusions   The recommended use of imrt with concurrent chemotherapy as an improvement over 3D-crt for management of anal canal carcinoma achieves a high probability of local control and colostomy-free survival without excessive risk for acute or late treatment-related toxicities.

Sign in / Sign up

Export Citation Format

Share Document