Optimized Conformal Total Body Irradiation Among Recipients of TCRαβ/CD19-Depleted Grafts in Pediatric Patients With Hematologic Malignancies: Single-Center Experience

Total body irradiation (TBI) in combination with chemotherapy is widely used as a conditioning regimen in pediatric and adult hematopoietic stem cell transplantation (HSCT). The combination of TBI with chemotherapy has demonstrated superior survival outcomes in patients with acute lymphoblastic and myeloid leukemia when compared with conditioning regimens based only on chemotherapy. The clinical application of intensity-modulated radiation therapy (IMRT)-based methods (volumetric modulated arc therapy (VMAT) and TomoTherapy) seems to be promising and has been actively used worldwide. The optimized conformal total body irradiation (OC-TBI) method described in this study provides selected dose reduction for organs at risk with respect to the most significant toxicity (lungs, kidneys, lenses). This study included 220 pediatric patients who received OC-TBI with subsequent chemotherapy and allogenic HSCT with TCRαβ/CD19 depletion. A group of 151 patients received OC-TBI using TomoTherapy, and 40 patients received OC-TBI using the Elekta Synergy™ linac with an Agility-MLC (Elekta, Crawley, UK) using volumetric modulated arc therapy (VMAT). Twenty-nine patients received OC-TBI with supplemental simultaneous boost to bone marrow—(SIB to BM) up to 15 Gy: 28 patients (pts)—TomoTherapy; one patient—VMAT. The follow-up duration ranged from 0.3 to 6.4 years (median follow-up, 2.8 years). Overall survival (OS) for all the patients was 63% (95% CI: 56–70), and event-free survival (EFS) was 58% (95% CI: 51–65). The cumulative incidence of transplant-related mortality (TRM) was 10.7% (95% CI: 2.2–16) for all patients. The incidence of early TRM (<100 days) was 5.0% (95% CI: 1.5–8.9), and that of late TRM (>100 days) was 5.7 (95% CI: 1.7–10.2). The main causes of death for all the patients were relapse and infection. The concept of OC-TBI using IMRT VMAT and helical treatment delivery on a TomoTherapy treatment unit provides maximum control of the dose distribution in extended targets with simultaneous dose reduction for organs at risk. This method demonstrated a low incidence of severe side effects after radiation therapy and predictable treatment effectiveness. Our initial experience demonstrates that OC-TBI appears to be a promising technique for the treatment of pediatric patients.

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Feasibility study of volumetric modulated arc therapy with Halcyon™ linac for total body irradiation

Radiation Oncology ◽

10.1186/s13014-021-01959-3 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Takuya Uehara ◽

Hajime Monzen ◽

Mikoto Tamura ◽

Masahiro Inada ◽

Masakazu Otsuka ◽

...

Keyword(s):

Total Body Irradiation ◽

Organs At Risk ◽

Volumetric Modulated Arc Therapy ◽

Dose Calculation ◽

Target Volume ◽

The Body ◽

Whole Body ◽

Data Set ◽

Arc Therapy ◽

Total Body

Abstract Background The use of total body irradiation (TBI) with linac-based volumetric modulated arc therapy (VMAT) has been steadily increasing. Helical tomotherapy has been applied in TBI and total marrow irradiation to reduce the dose to critical organs, especially the lungs. However, the methodology of TBI with Halcyon™ linac remains unclear. This study aimed to evaluate whether VMAT with Halcyon™ linac can be clinically used for TBI. Methods VMAT planning with Halcyon™ linac was conducted using a whole-body computed tomography data set. The planning target volume (PTV) included the body cropped 3 mm from the source. A dose of 12 Gy in six fractions was prescribed for 50% of the PTV. The organs at risk (OARs) included the lens, lungs, kidneys, and testes. Results The PTV D98%, D95%, D50%, and D2% were 8.9 (74.2%), 10.1 (84.2%), 12.6 (105%), and 14.2 Gy (118%), respectively. The homogeneity index was 0.42. For OARs, the Dmean of the lungs, kidneys, lens, and testes were 9.6, 8.5, 8.9, and 4.4 Gy, respectively. The V12Gy of the lungs and kidneys were 4.5% and 0%, respectively. The Dmax of the testes was 5.8 Gy. Contouring took 1–2 h. Dose calculation and optimization was performed for 3–4 h. Quality assurance (QA) took 2–3 h. The treatment duration was 23 min. Conclusions A planning study of TBI with Halcyon™ to set up VMAT-TBI, dosimetric evaluation, and pretreatment QA, was established.

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Volumetric Modulated Arc Therapy (VMAT) for Whole-Brain Radiation Therapy: Not Only for Hippocampal Sparing, but for Reduction of Dose to Other Organs at Risk

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2015.07.1791 ◽

2015 ◽

Vol 93 (3) ◽

pp. E487

Author(s):

S.S. Sood ◽

D. Pokhrel ◽

C.E. Lominska ◽

P. Kumar ◽

R.K. Badkul ◽

...

Keyword(s):

At Risk ◽

Radiation Therapy ◽

Organs At Risk ◽

Volumetric Modulated Arc Therapy ◽

Whole Brain Radiation Therapy ◽

Whole Brain ◽

Whole Brain Radiation ◽

Arc Therapy ◽

Hippocampal Sparing ◽

Brain Radiation

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Dosimetric comparison of organs at risk with three-dimensional conformal radiation, intensity-modulated radiation and volumetric-modulated arc therapy in cervical cancer: a cross sectional study

International Journal of Advances in Medicine ◽

10.18203/2349-3933.ijam20210978 ◽

2021 ◽

Author(s):

Febin Antony ◽

Mathew Varghese K. ◽

Jomon Raphael C. ◽

Paul Gopu G. ◽

S. Sivakumar

Keyword(s):

Cervical Cancer ◽

At Risk ◽

Bone Marrow ◽

Radiation Therapy ◽

Radiation Exposure ◽

Organs At Risk ◽

Volumetric Modulated Arc Therapy ◽

Three Dimensional ◽

Intensity Modulated ◽

Arc Therapy

Three-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) are the three main radiotherapy treatment techniques for cervical cancer. Whether either technique significantly reduces the radiation exposure to organs at risk remains unclear. We dosimetrically compared the irradiated volumes of bone marrow, bladder and rectum in cervical cancer patients using 3DCRT, IMRT and VMAT techniques in those patients with FIGO stage IIIB cervical cancer, receiving chemo irradiation at our institute. A total of 10 patients were dosimetrically compared. Significant reduction in V10, V20, V30, V40, V50 Gy of bone marrow was observed with IMRT and VMAT when compared to 3DCRT. Similar results were seen with V20, V30, V40, V50 Gy of bladder, and V40, V50 Gy of rectum. While comparing IMRT and VMAT, statistically significant dose reduction was noted in V20 Gy of bone marrow and V20 and V30 Gy of bladder with VMAT. When compared with 3DCRT the use of IMRT and/or VMAT reduced the radiation exposure to bone marrow, bladder, and rectum volumes at various radiation dose levels. VMAT can further reduce the radiation exposure to bone marrow and bladder when compared with IMRT. Thus, we propose the use of VMAT in cervical cancer to reduce the OAR toxicities.

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Evaluation of volumetric modulated arc therapy (VMAT) — based total body irradiation (TBI) in pediatric patients

Reports of Practical Oncology & Radiotherapy ◽

10.5603/rpor.a2021.0061 ◽

2021 ◽

Author(s):

Kadir Yaray ◽

Edrine Damulira

Keyword(s):

Total Body Irradiation ◽

Pediatric Patients ◽

Volumetric Modulated Arc Therapy ◽

Arc Therapy ◽

Total Body

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A Collimator Setting Optimization Algorithm for Dual-Arc Volumetric Modulated Arc Therapy in Pancreas Stereotactic Body Radiation Therapy

Technology in Cancer Research & Treatment ◽

10.1177/1533033819870767 ◽

2019 ◽

Vol 18 ◽

pp. 153303381987076 ◽

Cited By ~ 2

Author(s):

Xinyi Li ◽

Jackie Wu ◽

Manisha Palta ◽

You Zhang ◽

Yang Sheng ◽

...

Keyword(s):

At Risk ◽

Radiation Therapy ◽

Optimization Algorithm ◽

Stereotactic Body Radiation Therapy ◽

Organs At Risk ◽

Volumetric Modulated Arc Therapy ◽

Target Dose ◽

Stereotactic Body Radiation ◽

Complexity Score ◽

Arc Therapy

Purpose: To optimize collimator setting to improve dosimetric quality of pancreas volumetric modulated arc therapy plan for stereotactic body radiation therapy. Materials and Methods: Fifty-five volumetric modulated arc therapy cases in stereotactic body radiation therapy of pancreas were retrospectively included in this study with internal review board approval. Different from the routine practice of initializing collimator settings with a template, the proposed algorithm simultaneously optimizes the collimator angles and jaw positions that are customized to the patient geometry. Specifically, this algorithm includes 2 key steps: (1) an iterative optimization algorithm via simulated annealing that generates a set of potential collimator settings from 39 cases with pancreas stereotactic body radiation therapy, and (2) a multi-leaf collimator modulation scoring system that makes the final decision of the optimal collimator settings (collimator angles and jaw positions) based on organs at risk sparing criteria. For validation, the other 16 cases with pancreas stereotactic body radiation therapy were analyzed. Two plans were generated for each validation case, with one plan optimized using the proposed algorithm ( Planopt) and the other plan with the template setting ( Planconv). Each plan was optimized with 2 full arcs and the same set of constraints for the same case. Dosimetric results were analyzed and compared, including target dose coverage, conformity, organs at risk maximum dose, and modulation complexity score. All results were tested by Wilcoxon signed rank tests, and the statistical significance level was set to .05. Results: Both plan groups had comparable target dose coverage and mean doses of all organs at risk. However, organs at risk (stomach, duodenum, large/small bowel) maximum dose sparing ( D0.1 cc and D0.03 cc) was improved in Planopt compared to Planconv. Planopt also showed lower modulation complexity score, which suggests better capability of handling complex shape and sparing organs at risk . Conclusions: The proposed collimator settings optimization algorithm successfully improved dosimetric performance for dual-arc pancreas volumetric modulated arc therapy plans in stereotactic body radiation therapy of pancreas. This algorithm has the capability of immediate clinical application.

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Effective Organs-at-Risk Dose Sparing in Volumetric Modulated Arc Therapy Using a Half-Beam Technique in Whole Pelvic Irradiation

Frontiers in Oncology ◽

10.3389/fonc.2021.611469 ◽

2021 ◽

Vol 11 ◽

Author(s):

Hyunsoo Jang ◽

Jiyeon Park ◽

Mark Artz ◽

Yawei Zhang ◽

Jacob C. Ricci ◽

...

Keyword(s):

At Risk ◽

Small Intestine ◽

Dose Reduction ◽

Organs At Risk ◽

Volumetric Modulated Arc Therapy ◽

Dose Volume Histograms ◽

Dose Volume ◽

Arc Therapy ◽

Dose Sparing ◽

Beam Technique

BackgroundAlthough there are some controversies regarding whole pelvic radiation therapy (WPRT) due to its gastrointestinal and hematologic toxicities, it is considered for patients with gynecological, rectal, and prostate cancer. To effectively spare organs-at-risk (OAR) doses using multi-leaf collimator (MLC)’s optimal segments, potential dosimetric benefits in volumetric modulated arc therapy (VMAT) using a half-beam technique (HF) were investigated for WPRT.MethodsWhile the size of a fully opened field (FF) was decided to entirely include a planning target volume in all beam’s eye view across arc angles, the HF was designed to use half the FF from the isocenter for dose optimization. The left or the right half of the FF was alternatively opened in VMAT-HF using a pair of arcs rotating clockwise and counterclockwise. Dosimetric benefits of VMAT-HF, presented with dose conformity, homogeneity, and dose–volume parameters in terms of modulation complex score, were compared to VMAT optimized using the FF (VMAT-FF). Consequent normal tissue complication probability (NTCP) by reducing the irradiated volumes was evaluated as well as dose–volume parameters with statistical analysis for OAR. Moreover, beam-on time and MLC position precision were analyzed with log files to assess plan deliverability and clinical applicability of VMAT-HF as compared to VMAT-FF.ResultsWhile VMAT-HF used 60%–70% less intensity modulation complexity than VMAT-FF, it showed superior dose conformity. The small intestine and colon in VMAT-HF showed a noticeable reduction in the irradiated volumes of up to 35% and 15%, respectively, at an intermediate dose of 20–45 Gy. The small intestine showed statistically significant dose sparing at the volumes that received a dose from 15 to 45 Gy. Such a dose reduction for the small intestine and colon in VMAT-HF presented a significant NTCP reduction from that in VMAT-FF. Without sacrificing the beam delivery efficiency, VMAT-HF achieved effective OAR dose reduction in dose–volume histograms.ConclusionsVMAT-HF led to deliver conformal doses with effective gastrointestinal-OAR dose sparing despite using less modulation complexity. The dose of VMAT-HF was delivered with the same beam-on time with VMAT-FF but precise MLC leaf motions. The VMAT-HF potentially can play a valuable role in reducing OAR toxicities associated with WPRT.

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Hybrid volumetric-modulated arc therapy for postoperative breast cancer including regional lymph nodes: the advantage of dosimetric data and safety of toxicities

Journal of Radiation Research ◽

10.1093/jrr/rraa057 ◽

2020 ◽

Vol 61 (5) ◽

pp. 747-754

Author(s):

Yoshiko Doi ◽

Minoru Nakao ◽

Hideharu Miura ◽

Shuichi Ozawa ◽

Masahiro Kenjo ◽

...

Keyword(s):

Breast Cancer ◽

Lymph Nodes ◽

Irradiation Dose ◽

Organs At Risk ◽

Volumetric Modulated Arc Therapy ◽

Conformity Index ◽

Regional Lymph Nodes ◽

Dosimetric Data ◽

Arc Therapy

ABSTRACT To improve the homogeneity and conformity of the irradiation dose for postoperative breast cancer including regional lymph nodes, we planned Hybrid volumetric-modulated arc therapy (VMAT), which combines conventional tangential field mainly for the chest area and VMAT mainly for the supraclavicular area and marginal zone. In this study, we compared the dosimetric impact between traditional 3D conformal radiotherapy (3DCRT) and Hybrid VMAT and observed toxicities following Hybrid VMAT. A total of 70 patients indicated between October 2016 and December 2017 were included. The prescribed dose was 50 Gy/25 fractions. For the dosimetric impact, 3DCRT and Hybrid VMAT plans were compared in each patient with respect to the dosimetric parameters. Toxicities were followed using the Common Terminology Criteria for Adverse Events version 4.0. The median follow-up duration was 319 days. For the dosimetric impact, the homogeneity index (HI) and conformity index (CI) of PTV were significantly improved in the Hybrid VMAT plan compared with that in the 3DCRT plan (HI, 0.15 ± 0.07 in Hybrid VMAT vs 0.41 ± 0.19 in 3DCRT, P < 0.001; CI, 1.61 ± 0.44 in Hybrid VMAT vs 2.10 ± 0.56 in 3DCRT, P < 0.001). The mean irradiated ipsilateral lung dose was not significantly different in both plans (12.0 ± 2.4 Gy in Hybrid VMAT vs 11.8 ± 2.8 Gy in 3DCRT, P < 0.533). Regarding toxicity, there were no patients who developed ≥grade 3 acute toxicity and ≥grade 2 pneumonitis during the follow-up. Hybrid VMAT for postoperative breast cancer including regional lymph nodes was a reasonable technique that improved the homogeneity and conformity of the irradiation dose to the planning target volume while keeping the irradiation dose to organs at risk to a minimum.

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