scholarly journals Practical guidance in the use of image-guided radiotherapy systems

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
A. Pastorino ◽  
L. Todisco ◽  
E. Cazzulo ◽  
L. Berretta ◽  
A. Orecchia ◽  
...  
Keyword(s):  
Electronic System ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
Pre Treatment ◽  
Portal Images ◽  
Set Up ◽  
Geographic Miss ◽  
Technical Solutions ◽  
Modern Image ◽  
Delivered Dose

From mega-voltage portal images acquired on an electronic system (EPID), technological research has developed 3D and recently 4D volumetric verification modalities, allowing a direct visualization of the target, a direct comparison with the planning-TC and an optimization of the treatment (reduction of set-up errors, verification of the need for re-planning), leading to the very modern Image Guided RadioTherapy (IGRT). IGRT allows different technical solutions through direct or indirect visualization of the tumor and the acquisition of pre-treatment verification images, allowing to identify, quantify and correct errors related to set-up and organ-tumor motion, obtaining a greater compliance of the delivered dose, decreasing the risk of "geographic miss" and toxicity to healthy tissues and reducing the margins from CTV to PTV for the implementation of "dose escalation" protocols.

Prognostic value of copy-number alterations of the Cohesin complex in intermediate-risk prostate cancer recurrence.

2016 ◽  
Vol 34 (2_suppl) ◽  
pp. 49-49
Author(s):  
Jonathan So ◽  
Melvin Chua ◽  
Emilie Lalonde ◽  
Osman Mahamud ◽  
Alejandro Berlin ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Copy Number ◽  
Intermediate Risk ◽  
Cohesin Complex ◽  
Biochemical Relapse ◽  
Copy Number Alterations ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
Risk Prostate Cancer ◽  
Pre Treatment

49 Background: The Cohesin complex plays a critical role in mitotic progression and post-replicative DNA damage repair. It serves to bring together sister chromatids both in metaphase and in homologous recombination repair following ionizing radiation. The complex has also been shown to be phosphorylated in the ATM/BRCA1 pathway. The expression of various proteins in the complex are dysregulated in many cancers: breast, prostate, etc. Interestingly, in breast cancer cell lines, Cohesin is required for MYC activation in response to estrogen. Our study sought to correlate copy number alterations in this pivotal complex with biochemical relapse in prostate cancer patients. Methods: Our cohort consists of 284 patients with D’ Amico-classified intermediate-risk prostate cancer, treated with image-guided radiotherapy (IGRT, N = 143) or radical prostatectomy (RadP, N = 141). Pre-treatment biopsies and prostatectomy samples were analyzed using the Affymetrix Oncoscan array. The Phoenix and AUA criteria was used to define biochemical relapse for RadP and IGRT patients respectively. Results: Copy number alterations of RAD21, SMC1B, and STAG1 were observed in 18% (n = 52), 6.3% (n = 18), and 12% (n = 35) of the cohort respectively. They were predominantly losses in SMC1B, but gains in RAD21 and STAG1. All three genes in the Cohesin complex were associated with increased risk of biochemical relapse: RAD21 on chromosome 8 (HR = 1.93, 95% CI 1.23, 3.02, Wald’s p = 0.004), SMC1B on chromosome 22 (HR = 3.37, 95% CI 1.91, 5.94, Wald’s p < 10-4), and STAG1 on chromosome 3 (HR = 1.74, 95% CI 1.04, 2.89, Wald’s p < 0.05). However, when controlled for percent genome alteration and pre-treatment serum PSA levels, only copy number loss of SMC1B was a significant predictor of biochemical relapse (HR = 2.95, 95% CI 1.62, 5.38, Wald’s p < 10-3). Conclusions: We identified a novel association of copy-number alterations in members of the Cohesin complex with biochemical recurrence following radical prostatectomy or image-guided radiotherapy. This points to the central role of Cohesin in cell-cycle and DNA damage pathways promoting prostate cancer progression.

scholarly journals A multicentre observational study evaluating image-guided radiotherapy for more accurate partial-breast intensity-modulated radiotherapy: comparison with standard imaging technique

2014 ◽  
Vol 1 (3) ◽  
pp. 1-74 ◽  
Author(s):  
Emma J Harris ◽  
Mukesh Mukesh ◽  
Rajesh Jena ◽  
Angela Baker ◽  
Harry Bartelink ◽  
...  
Keyword(s):  
Normal Tissue ◽  
Breast Tissue ◽  
Imaging Technique ◽  
Probability Model ◽  
Breast Radiotherapy ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
Safety Margins ◽  
Integrated Boost ◽  
Set Up

BackgroundWhole-breast radiotherapy (WBRT) is the standard treatment for breast cancer following breast-conserving surgery. Evidence shows that tumour recurrences occur near the original cancer: the tumour bed. New treatment developments include increasing dose to the tumour bed during WBRT (synchronous integrated boost) and irradiating only the region around the tumour bed, for patients at high and low risk of tumour recurrence, respectively. Currently, standard imaging uses bony anatomy to ensure accurate delivery of WBRT. It is debatable whether or not more targeted treatments such as synchronous integrated boost and partial-breast radiotherapy require image-guided radiotherapy (IGRT) focusing on implanted tumour bed clips (clip-based IGRT).ObjectivesPrimary – to compare accuracy of patient set-up using standard imaging compared with clip-based IGRT. Secondary – comparison of imaging techniques using (1) tumour bed radiotherapy safety margins, (2) volume of breast tissue irradiated around tumour bed, (3) estimated breast toxicity following development of a normal tissue control probability model and (4) time taken.DesignMulticentre observational study embedded within a national randomised trial: IMPORT-HIGH (Intensity Modulated and Partial Organ Radiotherapy – HIGHer-risk patient group) testing synchronous integrated boost and using clip-based IGRT.SettingFive radiotherapy departments, participating in IMPORT-HIGH.ParticipantsTwo-hundred and eighteen patients receiving breast radiotherapy within IMPORT-HIGH.InterventionsThere was no direct intervention in patients’ treatment. Experimental and control intervention were clip-based IGRT and standard imaging, respectively. IMPORT-HIGH patients received clip-based IGRT as routine; standard imaging data were obtained from clip-based IGRT images.Main outcome measuresDifference in (1) set-up errors, (2) safety margins, (3) volume of breast tissue irradiated, (4) breast toxicity and (5) time, between clip-based IGRT and standard imaging.ResultsThe primary outcome of overall mean difference in clip-based IGRT and standard imaging using daily set-up errors was 2–2.6 mm (p < 0.001). Heterogeneity testing between centres found a statistically significant difference in set-up errors at one centre. For four centres (179 patients), clip-based IGRT gave a mean decrease in the systematic set-up error of between 1 mm and 2 mm compared with standard imaging. Secondary outcomes were as follows: clip-based IGRT and standard imaging safety margins were less than 5 mm and 8 mm, respectively. Using clip-based IGRT, the median volume of tissue receiving 95% of prescribed boost dose decreased by 29 cm3(range 11–193 cm3) compared with standard imaging. Difference in median time required to perform clip-based IGRT compared with standard imaging was X-ray imaging technique dependent (range 8–76 seconds). It was not possible to estimate differences in breast toxicity, the normal tissue control probability model indicated that for breast fibrosis maximum radiotherapy dose is more important than volume of tissue irradiated.Conclusions and implications for clinical practiceMargins of less than 8 mm cannot be used safely without clip-based IGRT for patients receiving concomitant tumour bed boost, as there is a risk of geographical miss of the tumour bed being treated. In principle, smaller but accurately placed margins may influence local control and toxicity rates, but this needs to be evaluated from mature clinical trial data in the future.FundingThe National Institute for Health Research Efficacy and Mechanism Evaluation programme.

scholarly journals Set-up Errors and Determination of Planning Target Volume Margins Protocol for Different Anatomical Sites in a Newly Established Tertiary Radiotherapy Centre in India

2020 ◽  
Vol 6 (02) ◽  
pp. 81-87
Author(s):  
Avik Mandal ◽  
Pritanjali Singh ◽  
Soumen Bera ◽  
Avajeet Kumar ◽  
Dharmendra Singh ◽  
...  
Keyword(s):  
Head And Neck ◽  
Planning Target Volume ◽  
Random Error ◽  
Target Volume ◽  
Curative Intent ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
Number Of Patients ◽  
Set Up ◽  
The Brain

Abstract Objective Our study aimed to assess the set-up errors for image-guided radiotherapy at a newly established tertiary radiation center in India and to establish the departmental protocol of clinical target volume–planning target volume (CTV–PTV) margins for different anatomical sites. Materials and Methods This study enrolled the first 200 patients who were treated with curative intent at All India Institute of Medical Sciences, Patna, from February 2019 to September 2019. Number of patients were 53, 26, 53, 11, 6, 47, and 4 for head and neck, brain, breast, thorax, abdomen, pelvis, and craniospinal irradiation (CSI), respectively. The translational vectors for total 1,463 kV cone-beam computed tomography (CBCT) images were collected from the treatment record. Results For the systematic error, the largest value is found for the thoracic subset on the X and Y directions, and for breast patients on Z axis, whereas the smallest values were found for CSI. For random error, the largest value was found for pelvic in the X, Y direction, and for breast subset on Z axis, whereas the smallest values on X and Z axes were found in the brain and for head and neck on the Y axis. Largest value for systemic error is smaller than 5 mm in all directions and for all anatomical subsets. The highest random error value is 5.07 mm in Y axis for pelvic subset. The largest values for CTV–PTV margin are found for thoracic subset and the smallest for CSI followed by the brain. Significant reduction of set-up error observed for the last hundred patients as compared to the first half of the patient population. Conclusion Use of thermoplastic cast along with breast board and respiratory motion management should be recommended to reduce set-up error for breast and thoracic subset. Six degrees of freedom robotic couch system can also further rectify the set-up error in image-guided radiotherapy.

scholarly journals EP-1661: Six degree set up errors of spine tumors assessed by image guided radiotherapy

2015 ◽  
Vol 115 ◽  
pp. S910
Author(s):  
P. Jiang ◽  
S. Zhou ◽  
J.J. Wang ◽  
R.J. Yang ◽  
Z.Y. Liu ◽  
...  
Keyword(s):  
Image Guided Radiotherapy ◽  
Image Guided ◽  
Spine Tumors ◽  
Degree Set ◽  
Set Up

Image-guided radiation therapy for carcinoma of gallbladder: implication on margin for set-up errors

2013 ◽  
Vol 12 (3) ◽  
pp. 263-271 ◽  
Author(s):  
Gagan Saini ◽  
Vineeta Goel ◽  
Anil K Anand ◽  
Kamlesh Kumar Gupta
Keyword(s):  
Radiation Therapy ◽  
Gall Bladder ◽  
Target Volume ◽  
Image Guided Radiotherapy ◽  
Image Guided Radiation Therapy ◽  
Image Guided ◽  
Thermoplastic Mask ◽  
The Mean ◽  
Set Up ◽  
Upper Abdominal

AbstractPurposeA retrospective study was undertaken to analyse set-up variations in patients being treated with post-operative radiation therapy for carcinoma of gall bladder by image-guided radiotherapy (IGRT) using cone-beam computed tomography (CBCT) scans and paired kilovoltage beam portals (kVps).Materials and methodsThree consecutive patients receiving post-operative radiation therapy for carcinoma of gall bladder were studied. A total of 32 imaging studies were performed. The immobilisation system was an all-in-one system along with a thermoplastic mask, with knees either resting on the knee rest or in a vacuum cushion. The CBCT scans and kVps were reviewed in an off-line mode. The surrogate markers used for matching during co-registration were 12th rib, coeliac trunk, vertebral bodies and canal. Individual readings were used to calculate mean shifts (m); the mean of these means (M) was calculated to arrive at the systematic error in each direction and its standard deviation (Σ) was calculated. The margins for set-up error (SM) were then calculated.ResultsThere were a total of 32 readings of which 21 were CBCTs and 11 were kVps. The mean shifts in each direction for each patient were 0·06, 0·25 and 0·15 cm in vertical, longitudinal and lateral directions, respectively. The resultant planning target volume margins calculated were 0·24, 0·9 and 0·47 cm in vertical, longitudinal and lateral directions.ConclusionsIGRT for upper abdominal malignancies using CBCT and kVps is a useful method to keep the margins for set-up error low. The use of surrogates for matching should be relevant to the target volume. Good immobilisation system helps in keeping the margins low.

Residual rotational set-up errors after daily cone-beam CT image guided radiotherapy of locally advanced cervical cancer

2012 ◽  
Vol 105 (2) ◽  
pp. 220-225 ◽  
Author(s):  
Louise Vagner Laursen ◽  
Ulrik Vindelev Elstrøm ◽  
Anne Vestergaard ◽  
Ludvig P. Muren ◽  
Jørgen Baltzer Petersen ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Cone Beam Ct ◽  
Locally Advanced ◽  
Cone Beam ◽  
Ct Image ◽  
Advanced Cervical Cancer ◽  
Image Guided Radiotherapy ◽  
Locally Advanced Cervical Cancer ◽  
Image Guided ◽  
Set Up
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