scholarly journals Evaluation of interfraction patient setup errors for image-guided prostate and head-and-neck radiotherapy using kilovoltage cone beam and megavoltage fan beam computed tomography

2013 ◽  
Vol 12 (4) ◽  
pp. 334-343 ◽  
Author(s):  
X. Sharon Qi ◽  
Sutan Wu ◽  
Francis Newman ◽  
X. Allen Li ◽  
Angie Y. Hu
Keyword(s):  
Computed Tomography ◽  
Head And Neck ◽  
Target Volume ◽  
Cone Beam ◽  
Setup Errors ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
Significant Difference ◽  
Late Stages ◽  
Head And Neck Radiotherapy

AbstractPurposeTo analyse interfraction setup using two different image guidance modalities for prostate and head-and-neck (H&N) cancer treatment.Materials and methodsSeventy-two prostate and 60 H&N cancer patients, imaged with kilovoltage cone beam computed tomography (KVCBCT) or megavoltage fan beam computed tomography (MVFBCT), were studied retrospectively. The daily displacements in mediolateral (ML), craniocaudal (CC) and anteroposterior (AP) dimensions were investigated. The setup errors were calculated to determine the clinical target volume to planning target volume (CTV-to-PTV) margins.ResultsBased on 1,606 KVCBCT and 2,054 MVFBCT scans, average interfraction shifts in ML, CC and AP direction for H&N cases were 0·5 ± 1·5, −0·3 ± 2·0, 0·3 ± 1·7 mm using KVCBCT, 0·2 ± 1·9, −0·2 ± 2·4 and 0·0 ± 1·7 mm using MVFBCT. For prostate cases, average interfraction displacements were −0·3 ± 3·9, 0·2 ± 2·4, 0·4 ± 3·8 mm for MVFBCT and −0·2 ± 2·7, −0·6 ± 2·9, −0·5 ± 3·4 mm for KVCBCT. The calculated CTV-to-PTV margins, if determined by image-guided radiotherapy (IGRT) data, were 5·6 mm (H&N) and 7·8 mm (prostate) for MVFBCT, compared with 4·8 mm and 7·2 mm for KVCBCT. We observed no statistically significant difference in daily repositioning using KVCBCT and MVFBCT in early, middle and late stages of the treatment course.ConclusionIn the absence of IGRT, the CTV-to-PTV margin determined using IGRT data, may be varied for different imaging modalities for prostate and H&N irradiation.

Novel irradiation techniques in the treatment of solid tumours. Radiotherapy of metastases

2014 ◽  
Vol 155 (8) ◽  
pp. 283-290
Author(s):  
Árpád Mayer ◽  
Zsuzsa Póti
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Clinical Target Volume ◽  
Primary Tumour ◽  
Target Volume ◽  
Solid Tumours ◽  
Cone Beam ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
Technical Developments

Novel developments in percutaneous radiotherapy, such as positron emission tomography/computed tomography, adaptive radiation planning, intensity modulation radiotherapy and intensity modulated arc therapy (RapidArc), as well as the newer generation of image control (cone-beam computed tomography) and image guided radiotherapy ensure increased dosages of planning target volume and clinical target volume of solid tumours without damaging surrounding tissues and providing maximal protection. By raising the dosages of planned target volume and clinical target volume, these novel technical developments have created new indications in the treatment of solid tumours. With the aid of the cone-beam computed tomography and image guided radiotherapy the organ metastasis (lung, liver, spinal cord) and the primary tumour can be treated safety and effectively. Hypofractionation, dose escalation and the use of stereotactic devices can probably decrease radiation damage. The authors review the most common forms of evidence-based fractionation schemes used in irradiation therapy. Orv. Hetil., 2014, 155(8), 283–290.

scholarly journals CBCT image guidance in head and neck irradiation: the impact of daily and weekly imaging protocols

2015 ◽  
Vol 14 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Innocencia Nyarambi ◽  
Crispen Chamunyonga ◽  
Andrew Pearce
Keyword(s):  
Head And Neck ◽  
Target Volume ◽  
Setup Error ◽  
Imaging Data ◽  
Imaging Protocol ◽  
Setup Errors ◽  
Image Guided Radiotherapy ◽  
Significant Difference ◽  
The Mean ◽  
The Impact

AbstractPurposeThis study evaluated the impact of a daily and weekly image-guided radiotherapy protocols in reducing setup errors and setting of appropriate margins in head and neck cancer patients.Materials and methodsInterfraction and systematic shifts for the hypothetical day 1–3 plus weekly imaging were extrapolated from daily imaging data from 31 patients (964 cone beam computed tomography (CBCT) scans). In addition, residual setup errors were calculated by taking the average shifts in each direction for each patient based on the first three shifts and were presumed to represent systematic setup error. The clinical target volume (CTV) to planning target volume (PTV) margins were calculated using van Herk formula and analysed for each protocol.ResultsThe mean interfraction shifts for daily imaging were 0·8, 0·3 and 0·5 mm in the S-I (superior-inferior), L-R (left-right) and A-P (anterior-posterior) direction, respectively. On the other hand the mean shifts for day 1–3 plus weekly imaging were 0·9, 1·8 and 0·5 mm in the S-I, L-R and A-P direction, respectively. The mean day 1–3 residual shifts were 1·5, 2·1 and 0·7 mm in the S-I, L-R and A-P direction, respectively. No significant difference was found in the mean setup error for the daily and hypothetical day 1–3 plus weekly protocol. However, the calculated CTV to PTV margins for the daily interfraction imaging data were 1·6, 3·8 and 1·4 mm in the S-I, L-R and A-P directions, respectively. Hypothetical day 1–3 plus weekly resulted in CTV–PTV margins of 5, 4·2 and 5 mm in the S-I, L-R and A-P direction.ConclusionsThe results of this study show that a daily CBCT protocol reduces setup errors and allows setup margin reduction in head and neck radiotherapy compared to a weekly imaging protocol.

scholarly journals Target coverage of daily cone-beam computed tomography in breath-hold image-guided radiotherapy for gastric lymphoma

BJR|Open ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 20200062
Author(s):  
Shigeo Takahashi ◽  
Takamasa Nishide ◽  
Masato Tsuzuki ◽  
Hiroki Katayama ◽  
Masahide Anada ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Gastric Lymphoma ◽  
Target Volume ◽  
Cone Beam ◽  
Breath Hold ◽  
Target Coverage ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
The Mean

Objectives: We evaluated retrospectively the daily target coverage using cone-beam computed tomography (CBCT) in breath-hold image-guided radiotherapy (BH-IGRT) for gastric lymphoma. Methods: BH-IGRT was performed using a prescribed dose of 30.6 Gy in 17 fractions for the whole stomach. We assessed the target coverage of the whole stomach on daily CBCT images [daily clinical target volume (CTV)], which was delineated individually by two observers. We evaluated V95% (percentage of volume receiving ≥95% of the prescribed dose) of daily CTV. Results: In total, 102 fractions from 6 patients were assessed. The mean V95% of daily CTV was 97.2%, which was over 95%. In two of six patients, the V95% of daily CTV was over 95% for either observer in all fractions. One patient had significant interobserver variation (p = 0.013). In 95 fractions (93%), the V95% of daily CTV was over 95% for either observer. Conclusion: Daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable, even when using CBCT. Advances in knowledge: A previous study ascertained good daily target coverage in BH-IGRT for gastric lymphoma using in-room CT. Even when using CBCT in our study, daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable.

scholarly journals Low-Dose Image-Guided Pediatric CNS Radiation Therapy: Final Analysis From a Prospective Low-Dose Cone-Beam CT Protocol From a Multinational Pediatrics Consortium

2020 ◽  
Vol 19 ◽  
pp. 153303382092065 ◽  
Author(s):  
Sara R. Alcorn ◽  
Xian Chiong Zhou ◽  
Casey Bojechko ◽  
Rodrigo A. Rubo ◽  
Michael J. Chen ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Central Nervous System ◽  
Nervous System ◽  
Cone Beam Computed Tomography ◽  
Target Volume ◽  
Cone Beam ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
Setup Accuracy ◽  
Vector Magnitude

Background: Lower-dose cone-beam computed tomography protocols for image-guided radiotherapy may permit target localization while minimizing radiation exposure. We prospectively evaluated a lower-dose cone-beam protocol for central nervous system image-guided radiotherapy across a multinational pediatrics consortium. Methods: Seven institutions prospectively employed a lower-dose cone-beam computed tomography central nervous system protocol (weighted average dose 0.7 mGy) for patients ≤21 years. Treatment table shifts between setup with surface lasers versus cone-beam computed tomography were used to approximate setup accuracy, and vector magnitudes for these shifts were calculated. Setup group mean, interpatient, interinstitution, and random error were estimated, and clinical factors were compared by mixed linear modeling. Results: Among 96 patients, with 2179 pretreatment cone-beam computed tomography acquisitions, median age was 9 years (1-20). Setup parameters were 3.13, 3.02, 1.64, and 1.48 mm for vector magnitude group mean, interpatient, interinstitution, and random error, respectively. On multivariable analysis, there were no significant differences in mean vector magnitude by age, gender, performance status, target location, extent of resection, chemotherapy, or steroid or anesthesia use. Providers rated >99% of images as adequate or better for target localization. Conclusions: A lower-dose cone-beam computed tomography protocol demonstrated table shift vector magnitude that approximate clinical target volume/planning target volume expansions used in central nervous system radiotherapy. There were no significant clinical predictors of setup accuracy identified, supporting use of this lower-dose cone-beam computed tomography protocol across a diverse pediatric population with brain tumors.

scholarly journals Effect of Surgical Mask on Setup Error in Head and Neck Radiotherapy

2020 ◽  
Vol 19 ◽  
pp. 153303382097402
Author(s):  
Yi Ding ◽  
Pingping Ma ◽  
Wei Li ◽  
Xueyan Wei ◽  
Xiaoping Qiu ◽  
...  
Keyword(s):  
Head And Neck ◽  
Radiation Treatment ◽  
Virus Disease ◽  
T Test ◽  
Setup Error ◽  
Setup Errors ◽  
Significant Difference ◽  
The Mean ◽  
Head And Neck Radiotherapy ◽  
Head Neck

Purpose: With the widespread prevalence of Corona Virus Disease 2019 (COVID-19), cancer patients are suggested to wear a surgical mask during radiation treatment. In this study, cone beam CT (CBCT) was used to investigate the effect of surgical mask on setup errors in head and neck radiotherapy. Methods: A total of 91 patients with head and neck tumors were selected. CBCT was performed to localize target volume after patient set up. The images obtained by CBCT before treatment were automatically registered with CT images and manually fine-tuned. The setup errors of patients in 6 directions of Vrt, Lng, Lat, Pitch, Roll and Rotation were recorded. The patients were divided into groups according to whether they wore the surgical mask, the type of immobilization mask used and the location of the isocenter. The setup errors of patients were calculated. A t-test was performed to detect whether it was statistically significant. Results: In the 4 groups, the standard deviation in the directions of Lng and Pitch of the with surgical mask group were all higher than that in the without surgical mask group. In the head-neck-shoulder mask group, the mean in the Lng direction of the with surgical mask group was larger than that of the without surgical mask group. In the lateral isocenter group, the mean in the Lng and Pitch directions of the with surgical mask group were larger than that of the without surgical mask group. The t-test results showed that there was significant difference in the setup error between the 2 groups ( p = 0.043 and p = 0.013, respectively) only in the Lng and Pitch directions of the head-neck-shoulder mask group. In addition, the setup error of 6 patients with immobilization open masks exhibited no distinguished difference from that of the patients with regular immobilization masks. Conclusion: In the head and neck radiotherapy patients, the setup error was affected by wearing surgical mask. It is recommended that the immobilization open mask should be used when the patient cannot finish the whole treatment with a surgical mask.

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