Using the computed tomography in comparison to the orthogonal radiography based treatment planning in high dose rate (HDR) brachytherapy in cervical uteri cancer patients; a single institution feasibility study (original) (raw)
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Asian Pacific Journal of Cancer Prevention, 2014
Background: Dosimetric comparison of two dimensional (2D) radiography and three-dimensional computed tomography (3D-CT) based dose distributions with high-dose-rate (HDR) intracavitry radiotherapy (ICRT) for carcinoma cervix, in terms of target coverage and doses to bladder and rectum. Materials and Methods: Sixty four sessions of HDR ICRT were performed in 22 patients. External beam radiotherapy to pelvis at a dose of 50 Gray in 27 fractions followed by HDR ICRT, 21 Grays to point A in 3 sessions, one week apart was planned. All patients underwent 2D-orthogonal and 3D-CT simulation for each session. Treatment plans were generated using 2D-orthogonal images and dose prescription was made at point A. 3D plans were generated using 3D-CT images after delineating target volume and organs at risk. Comparative evaluation of 2D and 3D treatment planning was made for each session in terms of target coverage (dose received by 90%, 95% and 100% of the target volume: D90, D95 and D100 respectively) and doses to bladder and rectum: ICRU-38 bladder and rectum point dose in 2D planning and dose to 0.1cc, 1cc, 2cc, 5cc, and 10cc of bladder and rectum in 3D planning. Results: Mean doses received by 100% and 90% of the target volume were 4.24±0.63 and 4.9±0.56 Gy respectively. Doses received by 0.1cc, 1cc and 2cc volume of bladder were 2.88±0.72, 2.5±0.65 and 2.2±0.57 times more than the ICRU bladder reference point. Similarly, doses received by 0.1cc, 1cc and 2cc of rectum were 1.80±0.5, 1.48±0.41 and 1.35±0.37 times higher than ICRU rectal reference point. Conclusions: Dosimetric comparative evaluation of 2D and 3D CT based treatment planning for the same brachytherapy session demonstrates underestimation of OAR doses and overestimation of target coverage in 2D treatment planning.
2017
CT-imaging based planning in intracavitary brachytherapy allows optimization of the dose distribution by patient basis. In addition to classical used point dose, the dose-volume histogram (DVH) analysis enables further possibilities for prescribing and reporting the correct dose. A group of 18 patients were treated with 38 fractions using different applicators and CT-based treatment planning. Each application was analyzed in detail. The clinical target volumes were contoured and also the organs at risk. The dose administered to bladder and rectum was analyzed according to ICRU Reports 38 and dose-volume parameters (e.g. D2cc represents the minimal dose for the most irradiated 2 cm). The values of the doses were analyzed including the external beam radiotherapy. Total doses were biologically normalized to conventional 2 Gy fractions (α/β = 10 Gy for target and 3 Gy for organs at risk). Individual changes for active dwell positions and dwell weights are guided by a concept of DVH cons...
Asian Pacific Journal of Cancer Care
Background: Present study compares two high-dose-rate intracavitary brachytherapy (ICBT) planning methods using two-dimensional orthogonal radiography and three-dimensional computed tomography (3D-CT) with regard to dose to target volume and organs at risk (OAR) in carcinoma cervix. Methodology: ICBT plans for 22-patients were compared using 2D planning and three-dimensional computed tomography (3D-CT) planning techniques. 2D treatment plans were generated using 2D-orthogonal images and dose was prescribed at Point A while 3D-CT plans were generated using 3D-CT images after contouring target volume and organs at risk. In 2D planning rectal and bladder doses were assessed as per ICRU-38 and in 3D planning, 0.1cc, 0.2cc, 0.5cc and 1cc doses of bladder and rectum were evaluated. Doses to target and organ at risks (rectum and bladder) were compared for each planning method. Results: Mean dose received by D90, D95 and D100 was 8.05±1.59Gy, 7.19±1.43Gy and 4.79±0.93Gy respectively. ICRU b...
Analysis of Volumetric Dosimetry of Target Volumes and Organs at Risk on ICRU Point-Based Dose Planning in CT-Guided HDR Intracavitary Brachytherapy to Carcinoma Cervix, 2019
Introduction Intracavitary brachytherapy (ICBT) has been historically planned based on orthogonal X-rays with point A as prescription point and surrogate rectal and bladder points to determine the approximate dose to organs at risk. This was standardized based on ICRU report 38. However, with the availability of better imaging modalities (CT, MRI), it became obvious that those points were poor surrogates for the tumor or the organ at risk. The current study analyzes the volumetric dose distribution to tumor volume and risk organs, from CT image-guided point-based planning done for intracavitary high-dose-rate brachytherapy using Fletcher-Suit-Delclos applicator in locally advanced carcinoma cervix patients. Materials and Methods Fifty-one patients with locally advanced carcinoma cervix who were treated with ICBT were included. Point A-based dose planning was done based on CT images, on Oncentra TM treatment planning software. The doses to bladder point and rectal point were determined and were used for the purpose of dose prescription and optimization. Relevant target volumes and risk organ volumes were determined over the same plans, and dose measurements are taken. They were then analyzed for correlation and linear regression model using IBM SPSS Statistics version 23. Results The point A-based prescription dose did not adequately cover the target volume. CTV 90 obtained only 53.23% (95% CI 49.21-57.25) of the prescribed dose. The bladder point dose correlated well with all sub-volumes, especially D2cc bladder dose (r = 0.525, p = \ 0.001). It satisfied linear regression model with standardized beta of 0.665. On the contrary, the correlation with rectal point and D2cc rectal dose was not strong (r = 0.284, p = 0.055). The point-based dose underestimates bladder dose by 18.24 ± 7.77% and overestimates rectal dose by 5.46 ± 4.55%, both being statistically significant. Conclusions CT image-guided point A-based dose planning, without any volume-based optimization, has poor target volume coverage. There is disproportionate overestimation of dose to rectum and rectal wall while calculating from rectal point dose. The bladder point dose has good mathematical prediction for dose to bladder. However, volumetrically, it underestimates the actual dose. While point A-based planning on tomographic imaging can be a stepping stone toward image-guided brachytherapy, volume-based planning is necessary for optimizing the dose to primary tumor and managing risk organ dose properly.
Journal of Contemporary Brachytherapy, 2013
Purpose: Distension and shape of urinary bladder may vary during intracavitary brachytherapy (ICBT) for cervical cancer, significantly affecting doses to bladder, rectum , sigmoid colon and small intestine and consequently late radiation toxicities. This study is to evaluate the effects of different fixed volume bladder distention on dosimetry, assessed by three dimensional image based planning, in different organs at risk during the treatment of cervical cancer with ICBT. Material and methods: Forty seven cervical cancer patients (stage IB to IVA) were qualified for ICBT following external beam radiotherapy. Urinary bladder was distended with different volumes of normal saline instilled by a Foley's catheter. Planning CT scans were performed after insertion of applicators and three dimensional treatment planning was done on Brachyvision ® treatment planning system (Varian Medical Systems, Palo Alto, CA). Dose volume histograms were analyzed. Bladder, rectum, sigmoid colon and small intestine doses were collected for individual plans and compared, based on the amount of bladder filling. Results: Mean dose to the bladder significantly decreased with increased bladder filling. However, doses to the small volumes (0.1 cc, 1 cc, 2 cc) which are relevant for brachytherapy, did not change significantly with bladder filling for bladder, rectum or sigmoid colon. Nevertheless, all dose values of small intestine are decreased significantly with bladder filling. Conclusions: Bladder distension has no significant effect on doses received during brachytherapy by relevant volumes of bladder, rectum and sigmoid colon except intestine where values are decreased with bladder distension. A larger study with clinical correlation of late toxicities is essential for proper evaluation of this strategy.
Saudi Journal of Obstetrics and Gynecology, 2009
Aim: To compare the high dose rate (HDR) brachytherapy treatment planning using standard orthogonal radiography and computerized tomography (CT) for carcinoma of the cervix. Methods: Forty applications with orthogonal planning using the Brachy Vision treatment planning system version 7.3.10 were performed. Orthogonal and CT based planning in these applications were compared; the doses to point A, rectum and bladder were defined according to the American Brachytherapy Society (ABS) recommendation. Using CT planning, we calculated the dose volume histogram (DVH) for the CTV, rectum and bladder. Results: Using orthogonal films to prescribe to point A, only 63.5% of CTV received the prescribed dose. The mean dose to the bladder point is 2.9 Gy and 17% of the bladder volume was encompassed by 2.9 Gy isodose line. The mean dose at the rectum point is 3.4 Gy and 21% of the rectum volume was encompassed by 3.4 Gy isodose line. The maximum dose to the rectum and the bladder derived from the CT is 1.7 and 2.6 times higher than the orthogonal reference points. Conclusions: CT based treatment planning for HDR brachytherapy of cancer cervix is reliable and more accurate in definition and calculation of the dose to the target as well as the critical organs. It allows dose calculation based on the actual volume rather than points or bony landmarks.
Asian Pacific journal of cancer prevention : APJCP, 2014
CT based brachytherapy allows 3-dimensional (3D) assessment of organs at risk (OAR) doses with dose volume histograms (DVHs). The purpose of this study was to compare computed tomography (CT) based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the cervix treated with high-dose-rate (HDR) intracavitary brachytherapy (ICBT). Between March 2011 and May 2012, 20 patients were treated with 55 fractions of brachytherapy using tandem and ovoids and underwent post-implant CT scans. The external beam radiotherapy (EBRT) dose was 48.6 Gy in 27 fractions. HDR brachytherapy was delivered to a dose of 21 Gy in three fractions. The ICRU bladder and rectum point doses along with 4 additional rectal points were recorded. The maximum dose (DMax) to rectum was the highest recorded dose at one of these five points. Using the HDR plus 2.6 brachytherapy t...
Brachytherapy, 2020
This study is a comparison between revised Manchester Point A and International Commission on Radiation Units and measurements (ICRU) 89 reporterecommended Point A absorbed-dose reporting in intracavitary brachytherapy for patients with cervical carcinoma. METHODS AND MATERIALS: The retrospective dosimetric study is based on the data of 32 patients with cervical carcinoma treated with high-dose-rate brachytherapy. Patients received 21 Gy in three fractions (7.0 Gy X three fractions) to Point A (A flange , revised Manchester definition). All the patients were replanned with a new Point A (A icru89) defined on CT images as per the American Brachytherapy Society/ICRU-89. The data collected were compared with the data obtained from Point A (A flange). RESULTS: When using the A flange plan normalization method, the mean dose of 0.1 cc, 1 cc, and 2 cc bladder volumes was 820.79