scholarly journals Organ motion in linac-based SBRT for glottic cancer

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Annarita Perillo ◽  
Valeria Landoni ◽  
Alessia Farneti ◽  
Giuseppe Sanguineti
Keyword(s):  
Early Stage ◽  
Displacement Vector ◽  
Thyroid Cartilage ◽  
Three Dimensional ◽  
Target Volume ◽  
Glottic Cancer ◽  
Organ Motion ◽  
Delivery Times ◽  
Significant Difference ◽  
Pre Treatment

Abstract Purpose The purpose of this study is to evaluate inter- and intra-fraction organ motion as well as to quantify clinical target volume (CTV) to planning target volume (PTV) margins to be adopted in the stereotactic treatment of early stage glottic cancer. Methods and materials Stereotactic body radiotherapy (SBRT) to 36 Gy in 3 fractions was administered to 23 patients with early glottic cancer T1N0M0. Patients were irradiated with a volumetric intensity modulated arc technique delivered with 6 MV FFF energy. Each patient underwent a pre-treatment cone beam computed tomography (CBCT) to correct the setup based on the thyroid cartilage position. Imaging was repeated if displacement exceeded 2 mm in any direction. CBCT imaging was also performed after each treatment arc as well as at the end of the delivery. Swallowing was allowed only during the beam-off time between arcs. CBCT images were reviewed to evaluate inter- and intra-fraction organ motion. The relationships between selected treatment characteristics, both beam-on and delivery times as well as organ motion were investigated. Results For the population systematic (Ʃ) and random (σ) inter-fraction errors were 0.9, 1.3 and 0.6 mm and 1.1, 1.3 and 0.7 mm in the left-right (X), cranio-caudal (Y) and antero-posterior (Z) directions, respectively. From the analysis of CBCT images acquired after treatment, systematic (Ʃ) and random (σ) intra-fraction errors resulted 0.7, 1.6 and 0.7 mm and 1.0, 1.5 and 0.6 mm in the X, Y and Z directions, respectively. Margins calculated from the intra-fraction errors were 2.4, 5.1 and 2.2 mm in the X, Y and Z directions respectively. A statistically significant difference was found for the displacement in the Z direction between patients irradiated with > 2 arcs versus ≤ 2 arcs, (MW test, p = 0.038). When analyzing mean data from CBCT images for the whole treatment, a significant correlation was found between the time of delivery and the three dimensional displacement vector (r = 0.489, p = 0.055), the displacement in the Y direction (r = 0.553, p = 0.026) and the subsequent margins to be adopted (r = 0.626, p = 0.009). Finally, displacements and the subsequent margins to be adopted in Y direction were significantly greater for treatments with more than 2 arcs (MW test p = 0.037 and p = 0.019, respectively). Conclusions In the setting of controlled swallowing during treatment delivery, intra-fraction motion still needs to be taken into account when planning with estimated CTV to PTV margins of 3, 5 and 3 mm in the X, Y and Z directions, respectively. Selected treatments may require additional margins.

scholarly journals Dose-Volume Comparison of IMRT and PSPT Treatment Plans for Early-Stage Glottic Cancer

2020 ◽  
Vol 7 (2) ◽  
pp. 42-50
Author(s):  
Takahiro Kato ◽  
Nobukazu Fuwa ◽  
Masao Murakami
Keyword(s):  
Spinal Cord ◽  
Dose Distribution ◽  
Early Stage ◽  
Organs At Risk ◽  
Cricoid Cartilage ◽  
Thyroid Cartilage ◽  
Target Volume ◽  
Glottic Cancer ◽  
Volume Comparison ◽  
Prescription Dose

Abstract Purpose To clarify the dose distribution characteristics for early-stage glottic cancer by comparing the dose distribution between intensity-modulated radiation therapy (IMRT) and passive scattering proton therapy (PSPT) and to examine the usefulness of PSPT for early-stage glottic cancer. Materials and Methods Computed tomography datasets of 8 patients with T1-2 glottic cancer who had been treated by PSPT were used to create an IMRT plan in Eclipse with 7 fields and a PSPT plan in XiO-M with 2 fields. Organs at risk (OARs) included the carotid arteries, arytenoids, inferior constrictor muscles, strap muscles, thyroid cartilage, cricoid cartilage, and spinal cord. The prescription dose was 66 GyRBE in 33 fractions to the planning target volume (PTV). All plans were optimized such that 95% of the PTV received 90% of the prescription dose considering that the skin was slightly spared. Results The superiority of the PSPT was confirmed in all OARs. In the PSPT, the dose to the contralateral carotid artery and the spinal cord, which is slightly distant from the PTV, was dramatically reduced while maintaining the dose distribution uniformity of the PTV by comparison with IMRT. Conclusion PSPT for early-stage glottic cancer resulted in good target dose homogeneity and significantly spared the OARs as compared with the IMRT. PSPT is expected to be effective in reducing late effects and particularly useful for young people.

scholarly journals The influence of bracket torque on external apical root resorption in bimaxillary protrusion patients: a retrospective study

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Xiaojuan Zhang ◽  
Hong Zhou ◽  
Xiangling Liao ◽  
Yi Liu
Keyword(s):  
Root Resorption ◽  
Three Dimensional ◽  
Post Treatment ◽  
Maxillary Central Incisor ◽  
Paired Samples ◽  
Anterior Teeth ◽  
Significant Difference ◽  
High Torque ◽  
Pre Treatment ◽  
Bimaxillary Protrusion

Abstract Background To evaluate the difference in root resorption between standard torque self-ligating brackets and high torque self-ligating brackets in bimaxillary protrusion patients after orthodontic treatment. Methods Pre-treatment and post-treatment Cone beam computed tomography (CBCT) of 32 patients (16 treated with the high torque DamonQ 0.022″ bracket and 16 with the 0.022″ standard torque self-ligating bracket) were selected. The first premolars were extracted from all patients before treatment. After mini-screw implants were inserted into the buccal region between the second premolar and first molar, 150 g of force was applied to retract the upper and lower anterior teeth to close the extraction space on each side. CBCT images of all patients were taken before and after treatment. Three-dimensional reconstruction of the maxillary central incisor, lateral incisor and canine was conducted with Mimics 20.0 software. The volumes of the roots were calculated using Gomagics Studio 12.0 software. The differences between the pre-treatment and post-treatment root volumes were statistically evaluated with a paired-samples t-test. Results There was no statistically significant difference in root resorption degree between the two kinds of torque brackets. The patient’s degree of root resorption in the high torque self-ligating group was greater than that in the standard torque group. Conclusions There was no significant difference in root external apical resorption between the high torque self-ligating brackets and the standard torque self-ligating brackets in bimaxillary protrusion patients.

Stereotactic robotic radiosurgery for localized prostate cancer: Initial evaluation of acute toxicities

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e16006-e16006
Author(s):  
L. E. Ponsky ◽  
C. Lillibridge ◽  
J. Brindle ◽  
Y. Zhang ◽  
B. Wessels ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Early Stage ◽  
Transrectal Ultrasound ◽  
Target Volume ◽  
Post Treatment ◽  
Intermediate Risk ◽  
Rectal Pain ◽  
Robotic Radiosurgery ◽  
Risk Prostate Cancer ◽  
Pre Treatment

e16006 Background: We evaluated the initial acute toxicities experienced by patients treated with cyberknife fractionated radiosurgery for low and low-intermediate risk prostate cancer. Methods: Twenty-two patients with low or low-intermediate risk prostate cancer (T2a, GG 3+3=6 or 3+4=7, PSA <10) were enrolled prospectively on an IRB approved protocol and treated the planning target volume (PTV)(prostate+5mm margin) with cyberknife fractionated radiosurgery to a dose of 36.25 Gy in 5 fractions (7.25Gy/fraction). The target volume included the prostate and seminal vesicles. PSA values, AUA symptom scores (AUA SS), and NCI CTC acute toxicities were analyzed prior to radiosurgery and at 1 month (N=16), 3 months (N=12) and 6 months (N=5)post-treatment. Results: Patients treated on study included 12 with GG 3+3=6 cancer and 10 with GG 3+4=7 cancer. Mean patient age was 66 years old (range 49–79). Mean pre-treatment PSA was 5.29 (range 0.64–9.36) declining to 3.44 (range 0.00–10.43) at 1 month post treatment, 1.99 (range 0.31–3.99) at 3 months post-treatment and 2.08 (1.05–3.13) at 6 months post-treatment. Mean pre-treatment AUA SS was 7 (range 0.–18) increasing to 12 (range 2–29) at 1 month post treatment, decreasing to 8 (range 2–17) at 3 months post-treatment and 11 (3–17). There were 5 grade 1 acute toxicities including (diarrhea, fatigue, mild urinary frequency, hemorrhoid and a rash) and 7 grade 2 toxicities including (bladder spasms, painful urinary, bowel irregularity, rectal pain, urethritis and numbness in the upper thigh), all grade 1 and 2 toxicities resolved within three months of treatment. The one patient with grade 2 thigh numbness was not thought to be study related toxicity. Two patients developed grade 3 toxicity. One developed bacteremia after the transrectal ultrasound guided placement of the fiducials, the infection completely resolved after treatment with antibiotics. One patient on Coumadin developed hematuria which resolved with conservative management. Conclusions: Cyberknife fractionated radiosurgery for patients with early stage prostate cancer appears to be safe on our early initial assessment.Continued evaluation and longer follow-up ongoing. [Table: see text]

The impact of image-guided radiotherapy (IGRT) for prostate cancer (PC) on radiotherapy (RT)-related acute toxicities and prostate-specific antigen (PSA) kinetics.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e15110-e15110 ◽  
Author(s):  
Darren M. C. Poon ◽  
CM Leung ◽  
CM Chu ◽  
WY Lee ◽  
Louis Lee ◽  
...  
Keyword(s):  
Image Guidance ◽  
Prostate Gland ◽  
Specific Antigen ◽  
Three Dimensional ◽  
Intensity Modulated Radiotherapy ◽  
Image Guided Radiotherapy ◽  
Psa Kinetics ◽  
Significant Difference ◽  
Pre Treatment ◽  
The Impact

e15110 Background: IGRT for PC could potentially improve the therapeutic ratio by enhancing accuracy of delivery of radiation to the prostate gland. Our aim is to compare the treatment outcomes in terms of RT-related acute toxicities and PSA kinetics of PC patients (pts) undergoing radical intensity-modulated radiotherapy (IMRT) with or without image-guidance. Methods: A cohort of 21 consecutive pts treated by IGRT (I) from January 2010, when the IGRT system was introduced in our institution, was compared with an immediately precedent cohort of 21 pts receiving IMRT without image-guidance (Non-I). The prescription dose (76Gy in 38 fractions) and the treatment margins were the same between the 2 groups (gps). In the I gp, daily online verification and correction of treatment position was performed with reference to image registration of the daily pre-treatment on-board imaging with the corresponding digitally reconstructed radiographs, based on three-dimensional matching of three intra-prostatic fiducial markers. Androgen deprivation therapy was not used in both gps. Acute toxicities were scored weekly during the course of RT according to the Common Terminology Criteria for Adverse Events Version 4.02. The pre- and the post-RT PSA within 6 months after completion of RT were obtained. The PSA halving time (PSAHT) was calculated by first order kinetics. Results: There was no statistically significant difference regarding the baseline clinical characteristics (age, PSA at diagnosis, Gleason score, T staging) between the gps. No grade 3 or 4 acute genitourinary (GU) or gastrointestinal (GI) toxicities was encountered in either gps. Acute grade 1 or 2 GI toxicities were significantly less frequent in the I gp (23.8% vs 81.0%, p=0.001), and their median duration of such toxicity were also significantly shorter (0.33 week vs 1.38 week, p=0.004).The frequencies of acute grade 1 or 2 GU toxicities were comparable between both gps (66.6% vs 81.0%, p=0.45).The I gp had a shorter median PSAHT than the non-I gp (3.36 week vs 5.49 week, p=0.09). Conclusions: IGRT is effective in reducing acute GI toxicities in treatment of PC, and may have more favorable PSA kinetics.

Early stage ovarian cancer: a randomized clinical trial comparing whole abdominal radiotherapy, melphalan, and intraperitoneal chromic phosphate: a National Cancer Institute of Canada Clinical Trials Group report.

1988 ◽  
Vol 6 (8) ◽  
pp. 1254-1263 ◽  
Author(s):  
D Klaassen ◽  
W Shelley ◽  
A Starreveld ◽  
M Kirk ◽  
D Boyes ◽  
...  
Keyword(s):  
Proportional Hazards ◽  
Residual Disease ◽  
Early Stage ◽  
Performance Status ◽  
Survival Rates ◽  
Disease Free Survival ◽  
Target Volume ◽  
Significant Difference ◽  
Abdominal Radiotherapy ◽  
Multifactor Analysis

Two hundred fifty-seven eligible patients with stage I, IIA "high risk" ovarian carcinoma and IIB, IIIO (disease confined to pelvis), were randomized to either total abdominal radiotherapy (arm A) 2,250 rad in 20 fractions (107 patients), melphalan (arm B) 8 mg/m2/d X 4 every 4 weeks X 18 courses (106 patients), or intraperitoneal chromic phosphate (arm C) 10 to 20 mCi (44 patients). All patients were initially treated with pelvic radiotherapy; arm A, 2,250 rad in ten fractions; and arms B and C, 4,500 rad in 20 fractions. Entry to arm C was discontinued early because of toxicity. In a multifactor analysis using proportional hazards models, no significant difference in survival was observed although there was a marginally significant difference in disease-free survival (P = .015) with arm B being superior to arm A. Stage (P less than .0001), grade (P less than .0001), and histology (P less than .008) were predictors of survival in the multifactor analysis. Performance status, age, and residual disease were significant predictors in the single factor analysis but were not predictive when correction was made for the effects of stage, grade, and histology. Five-year survival rates are 62% for arm A, 61% for arm B, and 66% for arm C. Median duration of follow-up is 8 years. Long-term complications of radiotherapy were seen in 19 patients on arm A, 11 on arm B, and 11 on arm C. Four patients who had received melphalan developed either a myelodysplastic syndrome or acute leukemia. Violations in covering the whole abdominal target volume were correlated with survival.

An investigation of rotational issues for rectal carcinoma treated with radiotherapy

2013 ◽  
Vol 13 (2) ◽  
pp. 195-202
Author(s):  
Dominique A. Taylor ◽  
Thomas ffrench ◽  
Charlotte A. Sale ◽  
Paul Foulstone
Keyword(s):  
Rectal Carcinoma ◽  
Three Dimensional ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Dose Volume Histograms ◽  
Action Threshold ◽  
Prescription Dose ◽  
Pre Treatment ◽  
Clinically Significant ◽  
Three Dimensional Conformal Radiotherapy

AbstractPurposeTo quantify the amount of inter-fractional pitch for rectal carcinoma patients, to investigate the dosimetric impact of pitch on the target volume and critical structures and to determine a tolerance where no pitch correction is required.Materials and methodsDaily pre-treatment images of rectal carcinoma patients were analysed to determine the residual pitch compared with the computed tomography (CT) planning scan. The dosimetric impact of pelvic rotation was modelled. The dose coverage of the clinical target volume (CTV) and small bowel were evaluated using dose–volume histograms.ResultsPre-treatment images had a mean of 0·27° and standard deviation was 2·23°. The volume of CTV receiving 95% of the prescription dose altered by 0·1% when up to ±10° of pitch was simulated.ConclusionsNo clinically significant change in CTV coverage was found (when ±10° of pitch was simulated). A tolerance of ±10° of pitch has been implemented for rectal carcinoma patients treated with three-dimensional conformal radiotherapy in our institution, when daily pre-treatment imaging with a zero action threshold for translational shifts is used.

Surgical Treatment for Early Stage Glottic Carcinoma with Involvement of the Anterior Commissure

2017 ◽  
Vol 158 (2) ◽  
pp. 295-302 ◽  
Author(s):  
Philipp Wolber ◽  
David Schwarz ◽  
Thoralf Stange ◽  
Magdalene Ortmann ◽  
Matthias Balk ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Local Recurrence ◽  
Cell Carcinoma ◽  
Recurrence Rate ◽  
Squamous Cell ◽  
Early Stage ◽  
Anterior Commissure ◽  
Glottic Cancer ◽  
Recurrence Rates ◽  
Significant Difference

Objective Assessment of the value of transoral laser microsurgery (TLM) compared with open surgery (OS) for early stage squamous cell carcinoma of the glottic larynx with special regard to involvement of the anterior commissure (AC). Study Design Case series with chart review. Setting Tertiary care otolaryngology clinic. Subjects and Methods Review of clinicopathological data of all patients with previously untreated T1a, T1b, and T2 glottic squamous cell carcinoma of the larynx who were consecutively enrolled over a 10-year period (January 1, 1992, to December 31, 2002). Results Local recurrence rate was 20.4% (10 of 49) for TLM and 10.7% (3 of 28) for OS. Comparison of the TLM and OS groups regarding local recurrence rates revealed a significant difference only for tumors invading the AC ( P = .046). Within the TLM group, tumors with involvement of the AC showed a significantly higher recurrence rate (38.1%; 8 of 21) compared with tumors without involvement of the AC (7.1%; 2 of 28; P = .008). In the OS group, involvement of the AC revealed no significant difference ( P = .45). The overall survival in both groups was comparable in both groups (TLM, 93.9%; OS, 89.3%; P = .47). Conclusion TLM and OS are equally effective surgical treatments for early stage glottic cancer without involvement of the AC, with selection of treatment based on pretreatment endoscopy. However, TLM is associated with less morbidity. In case of invasion of the AC, OS yields lower recurrence rates.

scholarly journals Comparison of the Gross Target Volumes Based on Diagnostic PET/CT for Primary Esophageal Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Jingzhen Shi ◽  
Jianbin Li ◽  
Fengxiang Li ◽  
Yingjie Zhang ◽  
Yanluan Guo ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Three Dimensional ◽  
Target Volume ◽  
Conformity Index ◽  
Ct Image ◽  
Thoracic Esophageal Cancer ◽  
Imaging Results ◽  
Pet Ct ◽  
Significant Difference ◽  
Target Volumes

BackgroundClinically, many esophageal cancer patients who planned for radiation therapy have already undergone diagnostic Positron-emission tomography/computed tomography (PET/CT) imaging, but it remains unclear whether these imaging results can be used to delineate the gross target volume (GTV) of the primary tumor for thoracic esophageal cancer (EC).MethodsSeventy-two patients diagnosed with thoracic EC had undergone prior PET/CT for diagnosis and three-dimensional CT (3DCT) for simulation. The GTV3D was contoured on the 3DCT image without referencing the PET/CT image. The GTVPET-ref was contoured on the 3DCT image referencing the PET/CT image. The GTVPET-reg was contoured on the deformed registration image derived from 3DCT and PET/CT. Differences in the position, volume, length, conformity index (CI), and degree of inclusion (DI) among the target volumes were determined.ResultsThe centroid distance in the three directions between two different GTVs showed no significant difference (P &gt; 0.05). No significant difference was found among the groups in the tumor volume (P &gt; 0.05). The median DI values of the GTVPET-reg and GTVPET-ref in the GTV3D were 0.82 and 0.86, respectively (P = 0.006). The median CI values of the GTV3D in the GTVPET-reg and GTVPET-ref were 0.68 and 0.72, respectively (P = 0.006).ConclusionsPET/CT can be used to optimize the definition of the target volume in EC. However, no significant difference was found between the GTVs delineated based on visual referencing or deformable registration whether using the volume or position. So, in the absence of planning PET–CT images, it is also feasible to delineate the GTV of primary thoracic EC with reference to the diagnostic PET–CT image.

scholarly journals The Influence of Bracket Torque on External Apical Root Resorption in Bimaxillary Protrusion Patients: A Retrospective Study

2021 ◽  
Author(s):  
Zhang Xiaojuan ◽  
Zhou Hong ◽  
Liao Xiangling ◽  
Sang Jinhua
Keyword(s):  
Root Resorption ◽  
Three Dimensional ◽  
Clinical Work ◽  
Post Treatment ◽  
Maxillary Central Incisor ◽  
Anterior Teeth ◽  
Significant Difference ◽  
High Torque ◽  
Pre Treatment ◽  
Bimaxillary Protrusion

Abstract Objectives: To evaluate the difference in root resorption between standard torque self-ligating brackets and high torque self-ligating brackets in bimaxillary protrusion patients after orthodontic treatment.Materials and Methods: Pre-treatment and post-treatment CBCT of 32 patients (16 treated with the high torque DamonQ 0.022” bracket and 16 with the 0.022” standard torque self-ligating bracket) were selected. The first premolars were extracted from all patients before treatment. After mini-screw implants were inserted into the buccal region between the second premolar and first molar, 150 g of force was applied to retract the upper and lower anterior teeth to close the extraction space on each side. CBCT images of all patients were taken before and after treatment. Three-dimensional reconstruction of the maxillary central incisor, lateral incisor and canine was conducted with Mimics 20.0 software. The volumes of the roots were calculated using Gomagics Studio 12.0 software. The differences between the pre-treatment and post-treatment root volumes were statistically evaluated with a paired-samples t-test.Results: There was no statistically significant difference in root resorption degree between the two kinds of torque brackets. The patient’s degree of root resorption in the high torque self-ligating group was greater than that in the standard torque group.Conclusions: There was no significant difference in root external apical resorption between the high torque self-ligating brackets and the standard torque self-ligating brackets in bimaxillary protrusion patients.Clinical Relevance: A comparison of the effects of different torque brackets on root resorption can provide some guidance for bracket selection in clinical work.

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