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Objective To investigate the effect of couch rotation angle on non-coplanar static intensity-modulated radiotherapy (IMRT) plan for gastric cancer and to provide a reference for clinical planning. Methods A retrospective analysis was conducted on patients who recently underwent postoperative IMRT for gastric cancer. Twenty patients who received radiotherapy in the centre of Radiation Oncology of Huanggang Central Hospital from August 2022 to January 2023 were selected. That were selected to receive a seven-field coplanar static IMRT plan based on a couch rotation angle of 0° as the control group. Then, based on the coplanar IMRT plan, only the couch rotation angle of gantry angles 30° and 330° was changed to 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, respectively, and nine different non-coplanar plans were established. The homogeneity index (HI), conformity index (CI) of the target volume, and monitor unit (MU), as well as Dmean, V20, and V30 of the left and right kidneys, Dmax, Dmean, V10, V20, and V30 of the spinal cord, and Dmax, Dmean, V10, V20, V30, and V40 of the small intestine and liver were compared among the 10 plans. The MU and the dosimetric parameters of the target volumes and When the couch rotation angle was 60°, the minimum HI and maximum CI of the target volume were 0.0714±0.0089 and 0.9271±0.0108, respectively, and the minimum MU was 438±26, with the best homogeneity and conformity in the target volume and the shortest machine treatment time (P＜0.05). When the couch rotation angle was 10°, the Dmax of the small intestine was lowest, being (4620.73±99.27) cGy. When the couch rotation angle was 60°, the Dmean of the left and right kidneys was lowest, being (1246.30±130.35) cGy and (1001.52±103.33) cGy, respectively; the V20 of the left and right kidneys was lowest, being 22.87±6.29 and 19.69±1.84, respectively; the V10 and V30 of the spinal cord were lowest, being 40.08±4.92 and 1.68±0.34, respectively (P＜0.05). Conclusion The couch rotation angle has some influence on the postoperative treatment planning for patients with gastric cancer. In the design of non-coplanar plan for gastric cancer, the couch rotation angle of 60° contributes to establishing a better radiotherapy plan.
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Objective:To evaluate the accuracy and stability of stereotactic radiosurgery (SRS) algorithm in optical surface imaging (OSI) system in non-coplanar radiotherapy.Methods:Three OSI imaging systems were used to measure the phantom repeatedly at different couch rotation angles to analyze the accuracy and stability of OSI system. Seven patients with multiple brain metastases who underwent single-center non-coplanar radiotherapy were randomly selected, and the accuracy and stability of OSI for patient imaging were analyzed. Stability is defined as the difference between the two OSI measurements when the couch is turned from 0° to a non 0° angle, and then back to 0°, using the 0° cone beam CT (CBCT) as the "gold standard". Accuracy is defined as the difference between OSI and CBCT (at 0° couch angle) measurement data. The measurement data with normal distribution were described as Mean ± SD. The data with non-normal distribution were expressed as M (Q). The difference of the former data was compared by one-way ANOVA, and the difference of the latter data was assessed by Kruskal-Wallis H nonparametric test. Results:For non-coplanarity, the translation accuracy of the phantom and the patient was ≤ 1.30 mm and ≤ 1.00 mm, and the rotation accuracy was ≤ 0.50° and ≤ 0.60°, respectively. The translation errors mainly occurred in the left-right and head-foot directions. In terms of stability, the maximum standard deviation of phantom coplanar translation and rotation was 0.06 mm and 0.06°. The maximum standard deviation of patient translation and rotation was 0.17 mm and 0.19°.Conclusions:Although the new SRS algorithm improves the non-coplanar accuracy, it still cannot meet the precise requirements of non-coplanar single isocenter radiotherapy for multiple brain metastases, especially in the left-right and head-foot directions. When the couch rotation angle is large, OSI is not recommended for image-guided radiotherapy. However, its high stability can be used to monitor the intrafractional motion of patients.
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Objective:To compare three fixed-field intensity-modulated radiotherapy (IMRT) plans for nasal cavity and paranasal sinus tumors, including the coplanar IMRT (C-IMRT) plan and the non-coplanar IMRT(NC-IMRT) plan which were based on a conventional C-arm LINAC (Trilogy), and the coplanar IMRT (H-IMRT) plan based on an O-ring LINAC (Halcyon).Methods:Based on the data of 10 patients in the Ningbo First Hospital from December 2018 to December 2021 with nasal cavity and paranasal sinus tumors who underwent postoperative radiotherapy, this study redesigned three IMRT plans with the same prescribed doses and optimization objectives. Then, this study compared the doses of target volumes and organ at risks(OARs), the validation pass rates, and the execution time of these plans. Friedman test was employed in this study, and multiple comparisons were further made in cases of different results.Results:The differences in the conformal index (CI) of PTV and PTV boost of the three plans were statistically significant ( χ2 = 7.51, 9.69, P < 0.05). The multiple comparisons showed that the median CI of the H-IMRT plan was higher than that of the NC-IMRT plan ( Z = 2.53, 2.68, P < 0.05). The differences in other parameters of target volumes were not statistically significant. Compared with the C-IMRT plan, the H-IMRT plan reduced the Dmax of bilateral lenses, bilateral corneas, ipsilateral optic nerve, and ipsilateral eyeball ( Z = 2.80, 2.80, 2.80, 2.80, 2.81, 2.09, P < 0.05). Compared with the C-IMRT plan, the NC-IMRT reduced the Dmax of bilateral lenses, corneas, and eyeballs and contralateral optic nerve ( Z = 2.80, 2.66, 2.80, 2.70, 2.29, 2.29, 2.65, P < 0.05) and reduced the Dmean of bilateral eyeballs ( Z = 2.80, 2.80, P < 0.05). Compared with the NC-IMRT plan, the H-IMRT plan reduced the Dmax of the ipsilateral lens and cornea ( Z = 2.50, 2.08, P < 0.05), but increased the Dmax of the contralateral optic nerve and the Dmean of bilateral eyeballs ( Z = 2.80, 2.80, 2.80, P < 0.05). The validation pass rate of the three plans met the institutional standards, and the differences were not statistically significant. Moreover, the H-IMRT plan had the shortest median execution time (172.00 s), followed by the C-IMRT plan (337.50 s), and the NC-IMRT plan (388.00 s). Conclusions:The verification pass rate of the three plans can achieve the requirements of treatment implementation. The three plans had similar dosimetric differences in target volumes. However, the H-IMRT and NC-IMRT plans can protect the normal tissues (especially optical organs) more effectively than the C-IMRT plan, which is conducive to reducing the toxicity after radiotherapy and provides space for local dose increase or the radiotherapy for the treatment of tumor recurrence. The execution efficiency of the three plans is in the order of H-IMRT > C-IMRT > NC-IMRT. It is necessary to select appropriate radiotherapy equipment and technology according to actual situations.
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Non-coplanar radiotherapy is a kind of radiotherapy technology which employs multiple non-coplanar fixed fields or non-coplanar arcs. The non-coplanar field can be defined that the central axis of each field is not on the same plane, while the non-coplanar arc can be described that the trajectory formed by each arc is not on the same plane. Compared with coplanar radiotherapy, non-coplanar radiotherapy can achieve multi-angle or multi-radian irradiation, which effectively improves the focusing level of ray and is beneficial to enlarge the radiation dose of the target area between the surrounding normal tissues. Its dosimetric advantages have been proven in multiple types of tumors, such as intracranial tumors, liver cancer and lung cancer, etc. Multiple approaches can be employed to realize non-coplanar radiotherapy, which can be divided into the non-coplanar conic radiotherapy, non-coplanar conformal radiotherapy, non-coplanar intensity-modulated radiotherapy and non-coplanar volumetric modulated arc therapy according to the established sequence. In this review, the development process and principal characteristics of these implementations were summarized.
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Objective To compare the dosimetric characteristics of non-coplanar and coplanar field technology in static intensity-modulated radiotherapy of gastric cancer patients, so as to provide a reference for clinical radiotherapy plan selection. Methods Thirty-six patients with gastric cancer were selected to receive intensity-modulated radiotherapy in Huanggang Central Hospital, which was designed plan A and B. Group A used 7-field coplanar technology, while Group B used 7-field non-coplanar technology. We compared the differences of the optimized monitor unit, the dosimetry of organs at risk and target areas between group A and group B. Results Both group A and B could meet the requirements of doctors. The homogeneity index (0.14 ± 0.02), the conformity index (0.98 ± 0.01), Dmin (4315.21 ± 16.74) cGy、Dmean (4679.28 ± 28.39) cGy and Dmax(4952.30 ± 33.26) cGy of target areas in group B were better than those of group A. Moreover, the monitor unit of group B was much lower than that of group A, and the difference was statistically significant (P < 0.05). The Dmax, Dmean, V15, V20 and V30 of the left and right kidneys in group B were lower than those of group A. The Dmax (3408.57 ± 46.03) cGy, Dmean (1250.32 ± 14.27) cGy and V20 (44.91% ± 6.67%) of spinal cord and the Dmax (3408.57 ± 46.03) cGy, Dmean (1720.55 ± 17.42) cGy, V20 (25.31% ± 7.78%) and V30 (18.52% ± 1.56%) of small intestine were also lower than those of group A. The differences were statistically significant (P < 0.05). Conclusion The non-coplanar field radiation plan has more advantages in terms of target dose distribution and protection of organs so that it can be more considerably used in the process of planning and design.
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Objective To compare the preoperative and postoperative dosimetric parameters in the treatment of spinal metastasis,and to verify the accuracy of 3D-printing non-coplanar template (3D-PNCT)combined with CT-guided 125I seed implantation for the treatment of spinal metastasis.Methods The treatment plans of 7 patients with spinal metastasis (9 lesions) from 2016 to 2018 receiving 3D-PNCT in combination with CT-guided 125I seed implantation were retrospectively analyzed.The dosimetric parameters including homogeneity index (HI),conformal index (CI),external index (EI),dose of 90％ target volume (Dg0),mPD,volume percent of 100％,150％,and 200％ prescribed dose V100、V150、V200 and D2cm3 of spinal cord were compared before and after operation.The british columbia cancer ageny particle implantation quality evaluation standard was applied to evaluate the quality of implantation.Results The HI,EI and CI,Dg0,mPD,V100,V150,V200 and D2cm3 of spinal cord did not significantly differ before and after the plan (all P＞0.05).Five were evaluated as excellent and 4 were assessed as good.Conclusion The postoperative dosimetric parameters of 3D-PNCT combined with CT guided 125I seed implantation of spinal metastasis are basically consistent with preoperative dosimetric parameters.The postoperative plans are evaluated as excellent or good,suggesting that the technology has a good therapeutic accuracy in the treatment of spinal metastasis.
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Objective To compare the dosimetric data between preoperative plans and postoperative verification in computed tomography (CT)-guided and 3D-printing non-coplanar template-assisted 125I seed implantation for head and neck tumor,aiming to explore the safety,feasibility and accuracy of the individualized template design method.Methods A total of 42 patients with recurrent/metastatic malignant head and neck tumor admitted to Peking University Third Hospital from January to December 2016 were recruited in this study.A prescribed dose of l10-160Gy was adopted.3D-printing non-coplanar templates were designed for 42 cases.The dosimetric parameters including D90,minimum peripheral dose (mPD),V100,V150,V200,conformal index (CI),external index (EI) and homogeneity index (HI) were statistically compared before and after surgery.Results All templates were properly implanted intraoperatively.Compared with preoperative planning,postoperative D90,V100,CI,EI and HI did not significantly differ (P=0.490,0.407,0.893,0.143 and 0.079),whereas mPD,V150 and V200 significantly differed (P=0.036,0.007 and 0.000).Conclusion After postoperative verification,the main dosimetric parameters have high therapeutic accuracy and properly match with preoperative planning,which can meet clinical requirements.
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Objective@#To compare the preoperative and postoperative dosimetric parameters in the treatment of spinal metastasis, and to verify the accuracy of 3D-printing non-coplanar template (3D-PNCT) combined with CT-guided 125I seed implantation for the treatment of spinal metastasis.@*Methods@#The treatment plans of 7 patients with spinal metastasis (9 lesions) from 2016 to 2018 receiving 3D-PNCT in combination with CT-guided 125I seed implantation were retrospectively analyzed. The dosimetric parameters including homogeneity index (HI), conformal index (CI), external index (EI), dose of 90% target volume(D90), mPD, volume percent of 100%, 150%, and 200% prescribed dose V100、V150、V200 and D2cm3 of spinal cord were compared before and after operation. The british columbia cancer ageny particle implantation quality evaluation standard was applied to evaluate the quality of implantation.@*Results@#The HI, EI and CI, D90, mPD, V100, V150, V200 and D2cm3 of spinal cord did not significantly differ before and after the plan (all P>0.05). Five were evaluated as excellent and 4 were assessed as good.@*Conclusion@#The postoperative dosimetric parameters of 3D-PNCT combined with CT guided 125I seed implantation of spinal metastasis are basically consistent with preoperative dosimetric parameters. The postoperative plans are evaluated as excellent or good, suggesting that the technology has a good therapeutic accuracy in the treatment of spinal metastasis.
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Objective@#To compare the dosimetric data between preoperative plans and postoperative verification in computed tomography (CT)-guided and 3D-printing non-coplanar template-assisted 125I seed implantation for head and neck tumor, aiming to explore the safety, feasibility and accuracy of the individualized template design method.@*Methods@#A total of 42 patients with recurrent/metastatic malignant head and neck tumor admitted to Peking University Third Hospital from January to December 2016 were recruited in this study. A prescribed dose of 110-160Gy was adopted.3D-printing non-coplanar templates were designed for 42 cases. The dosimetric parameters including D90, minimum peripheral dose (mPD), V100, V150, V200, conformal index (CI), external index (EI) and homogeneity index (HI) were statistically compared before and after surgery.@*Results@#All templates were properly implanted intraoperatively. Compared with preoperative planning, postoperative D90, V100, CI, EI and HI did not significantly differ (P=0.490, 0.407, 0.893, 0.143 and 0.079), whereas mPD, V150 and V200 significantly differed (P=0.036, 0.007 and 0.000).@*Conclusion@#After postoperative verification, the main dosimetric parameters have high therapeutic accuracy and properly match with preoperative planning, which can meet clinical requirements.
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Objective The objective of this study was to study the dosimetric characteristics and advantages of Non-coplanar IMRT techniques stereotactic body radiation therapy(SBRT)in the early stage of NSCLC.Methods Ten patients were selected with early stage of NSCLC.Treatment planning designed 9 fields coplanar IMRT and 9 fields Non-coplanar IMRT,respectively.Non-coplanar plans include five coplanar fields and four non-coplanar fields.Two group patients' plans compared V2.5,V5,V20,V25 of the whole lung,the average exposure doses of the whole lung,and the average exposure doses of the contralateral lung.The comparison of the other OARs include:spinal cord Dmax,heart Dmax,esophagus Dmax,trachea Dmax,chest wall Dmax and V30 of chest wall.At the meantime,we compared the conformal index of PTV(CI)and the homogenization index of PTV(HI).Results Non-coplanar plans reduced V20 of the whole lung(P=0.001),the average exposure dose of the contralateral lung(P=0.001),but V5 of the whole lung non-coplanar plans were increased than that in coplanar plans(P=0.002).Non-coplanar technology reduce max dose of spinal cord,esophagus,trachea,chest wall and V30 of chest wall(P=0.026,0.001,0.026,0.008,0.016).Heart Dmax of the non-coplanar plans was high in coplanar plans with no statistical significance difference(P=0.296).The conformal index of PTV of the non-coplanar plans was better(P=0.036),there was no difference in the homogenization index of PTV(P=0.254).Conclusion The stereotactic body radiation therapy of the early stage of NSCLC,the non-coplanar technology can effectively reduce exposure doses of the lung tissue and the other most OARs,also improve the conformal index of the PTV.The non-coplanar technology have possibility in reducing complications when compared with the coplanar technology and therefore has certain dosimetry advantage.
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Objective To compare the dosimetric data between preoperative plans and postoperative verification in computed tomography (CT)-guided and 3D-printing non-coplanar templateassisted 125I seed implantation for pelvic tumor,and to explore the feasibility and accuracy of the personalized template designmethod.Methods A total of 51 patients registered from Dec 2015 to Dec 2016 who were applied with 3D-printing guided template assisted radioactive seed implantations in the hospital were included in this study.A prescribed dose of 110-160 Gy was adopted.3D-printing templates were designed and produced for 51 cases.The dosimetric parameters:Dg0,minimum peripheral dose (mPD),V100,V150,V200,conformal index (CI),external index (EI),and homogeneity index (HI) were compared between pre-and post-plans.Results 51 cases' templates were in place well during the operations.Compared with the preoperative planning,the postoperative D90,V100,V150,V200,CI,EI and HI differences had no statistical difference (P ＞ 0.05);mPD is larger than before (t =-2.96,P ＜ 0.05).Conclusions The main dosimetric parameters of postoperative verification were consistent well with the preoperative planning and have good accuracy,which could meet the clinical requirements.
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Objective To investigate the accuracy of 3D-printing non-coplanar template (3D-PNCT) assisted 125I seed implantation with CT guidance in the pelvic recurrent cervical between the preplan and post-plan dosimetric parameters.Methods Nine patients with pelvic recurrent cervical cancer received 125I seed implantation under CT guidance assisted with 3D-PNCT.A pre-plan based brachytherapy treatment planning system (B-TPS) assisted with 3D-PNCT for seed needle depth,direction and angle was designed.The dosimetry parameters including homogeneity index (HI),dose of 90％ target volume (Dg0),mPD,volume percent of 100％,150％ and 200％ prescribed dose V100,V150 and V200 and organ at risk between the pre-plan and post-plan were compared.Results Total seeds number was 675 (median 44,25-114) according to pre-plan,and 669 (median 47,25-113) seeds were implanted actually.138 needles need implant according to preplan,and 132 needles was implanted actually.The median angle deviation was 1.99 ° ± 2.94°(0 °-13 °).There was no significant difference of HI,EI and CI between perand post-plan.The differences of D90,MPD,V100,V150 and V200 between pre-and post-plan were not significant.Conclusions The confidence of pre-plan and post-plan for 3D-PNCT assisted 125I seed implantation in the pelvic recurrent cervical cancer could be accurately performed under CT guidance.
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Objective To investigate the acute side effect of 3D printing individual non-coplanar template for 125I seed implantation in head and neck recurrent/ metastatic carcinoma.Methods Between January 2016 and December 2016,42 patients of local recurrent malignant tumor of head and neck received 3D printing guide plate assist radioactive seeds implantations,and included in the study.The tumor volume ranged from 2.4 to 102.8 cm3 (median 28.6 cm3).The prescribed dose is 110-160 Gy,and the seeds activity were 0.34 to 0.70 mCi (1 Ci =3.7 × 1010 Bq).All patients carried out preoperative planning design,individual guide plate production,seed implantation,postoperative dose assessment,and followup.The side effects of skin,mucous membrane,blood and spinal cord were statistically analyzed.Results All patients were operated successfully.The follow-up time was 4-14 months (median 8.5 months).There were no adverse reactions at grade three or above.Three patients had grade one skin reaction.One patient experienced grade one mucosal reaction,two experienced grade two mucosal reactions.The skin response was correlated with the dose of the skin (x2 =7.067,P =0.032).No hematologic toxicity or radiation myelopathy was observed and no seed displacement was found.Conclusions 3D-printing guide plate can provide good accuracy for positioning and direction.For local recurrent malignant tumor of head and neck,there were no obvious adverse reactions and the operation was simple and the dosage was accurate.
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Objective To study the dosimetry and safety of the non-coplanar IMRT plan for advanced lung cancer.Methods The two groups IMRT plans were designed with coplanar (5,7F) and non-coplanar field (5,7F-n) for patients.To compare the dosimetry of two groups and perform 4 patients F7-n IMRT plan.Results With the increase of the fields in each group PTV's CI were improved (all P =0.000),especially the 7F-n plan PTV's Dmean,Dmax,V95％ and HI also were improved (P=0.001,0.001,0.009,0.000) ; in the coplanar group each lung' s V5 increased (P =0.000,0.002,0.000) and whole lung's Dmean increased (P =0.000),but non-coplanar group whole lung's and contralateral lung's V5 reduce (P =0.001,0.005).Between the groups,7F-n plan PTV's indicators were all improved to compared with 5F plan (all P =0.000),and each lung's V20 reduced (all P =0.000),and whole lung's Dmean,V30,contralateral lung' s V5 reduced (P =0.000,0.001,0.000),and spinal cord' s Dmax also reduced (P =0.033),but ipsilateral lung's V5 and heart's Dmean increased (P =0.000,0.003);with compared to 7F plan,the 7F-n's ipsilateral lung's V5 and heart's Dmean also increased (P =0.000,0.048),but whole lung' s and contralateral lung's V5 decreased (all P =0.000).Four patients were performed successfully non-coplanar IMRT treatment,no collision occurred.Conclusions 7 fields non-coplanar IMRT plan not only improve the dose distribution of PTV,but also effectively control the volume of low dose lung increase,lung V20 and Dmean reduce too.Thus recommended to use this design in patients with advanced lung cancer for radiotherapy
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Objective To investigate the dosimetric characteristics and their clinical applications of volumetric modulated Arc therapy (RapidArc) with fixed-fields intensity modulated radiotherapy for early stage nasal NK/T-cell lymphoma.Methods Ten patients with stage Ⅰ E and Ⅱ E nasal NK/T-cell lymphoma were enrolled in the study.Five field coplanar plan (5F),nine field coplanar plan (9F),five field non-coplanar plan (5F-N) and RapidArc plans were designed for each patient,in which 5F plan was set as the control group.Conformity index (CI) and homogeneity index (HI) as well as the maximum dose of organs at risks were compared.Results The target CI of 5F,9F,5F-N and RapidArc plan was 0.419±0.159,0.478 ±0.181,0.465 ±0.121 and 0.518 ±0.111,respectively.Compared with 5F (0.136±0.038),the target HI of 9F and RapidArc plan was 0.111 ±0.027 and 0.112 ±0.031 (t =3.11,3.04,P ＜ 0.05).9F plan significantly increased the Dmax of lens in the contralateral side(t =2.82,P ＜ 0.05) and in ipsilateral side (t =3.25,P ＜ 0.05),while 5F-N plan decreased the Dmax of optical nerves by up to 9％.RapidArc plan effectively reduced the radiation to organs at risk in lens (t =3.25,P ＜0.05),eyes (t =3.25,P ＜0.05),optical nerve (t =2.57,P ＜0.05) and optical chaism(t =7.62,P ＜0.05).The delivery efficiency of four plans ranked as RapidArc ＞ 5F ＞ 5F-N ＞ 9F.Conclusions RapidArc produced statistically significant improvement in the dose distributions of targets,and also reduced the Dmax of organs at risk,which would be the better choice of radiotherapy for nasal NK/T-cell lymphoma.