This study compared dosimetric parameters of step-and-shoot IMRT (SaS-IMRT) versus helical tomotherapy (HT) for whole-pelvis irradiation in cervical cancer patients. Treatment plans were generated for 20 patients using each technique. All PTV dosimetric parameters were significantly better with HT than SaS-IMRT. HT also provided more accurate CTV coverage and more homogeneous PTV dose distribution. Organ-at-risk sparing was significantly better with HT for the bladder, rectum and left femur. Beam-on time was significantly shorter with HT. HT provided superior target coverage and organ-at-risk sparing compared to SaS-IMRT.
IORT uses a high single-fraction radiation dose (10-30 Gy) is delivered during surgery to a surgically-exposed tumour bed, immediately after a chunk of the tumour has been surgically excised. This slide includes topics like APBI, IOERT, IOHDR.
IORT uses a high single-fraction radiation dose (10-30 Gy) is delivered during surgery to a surgically-exposed tumour bed, immediately after a chunk of the tumour has been surgically excised. This slide includes topics like APBI, IOERT, IOHDR.
Conformal Radiotherapy in Head and neck cancers is essential in terms of improving quality of life and local control in this era. This presentation aimed at giving an overview of conformal radiotherapy and its role in HNC to a 'general audience'.
Sharing about “A typical day in the life as Radiation Therapy Technologist (RTT)” includes their roles, responsibilities, duties, working protocols, management, working stress, daily challenges in this modern radiotherapy era. As well as a bit information about how to become a RTT in India.
A primer of oncology basics for nursing students. Includes basic oncology, understanding cancer and understanding radiation therapy in an easy to comprehend manner.
Here you can know about the teletherapy techniques which is used in radiation therapy. It can also help you to prepare notes on them. You can download it in your PC or laptop to see the gif, it will clear the concept better.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Conformal Radiotherapy in Head and neck cancers is essential in terms of improving quality of life and local control in this era. This presentation aimed at giving an overview of conformal radiotherapy and its role in HNC to a 'general audience'.
Sharing about “A typical day in the life as Radiation Therapy Technologist (RTT)” includes their roles, responsibilities, duties, working protocols, management, working stress, daily challenges in this modern radiotherapy era. As well as a bit information about how to become a RTT in India.
A primer of oncology basics for nursing students. Includes basic oncology, understanding cancer and understanding radiation therapy in an easy to comprehend manner.
Here you can know about the teletherapy techniques which is used in radiation therapy. It can also help you to prepare notes on them. You can download it in your PC or laptop to see the gif, it will clear the concept better.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Abstract—Colorectal cancer is leading cancer-related public health problem. This study was conducted to determine the effect of High-Dose-Rate intraluminal brachytherapy (HDR-BT) with or without interstitial brachytherapy during neoadjuvant chemoradiation for locally advanced rectal cancer. This randomized contrial was conducted on 28 patients attended with locally advanced rectal cancer (T3, T4 or N+) treated initially with concurrent capecitabine (800 mg/m2 twice daily for 5 days per week) and pelvic external beam radiation therapy (45Gy in 25 Fractions) after one week MRI for all patients; received intraluminal HDR-BT with 4Gy x 2 Fractions with one week interval for those had gross residual disease within 1cm of rectal wall and receiveed intraluminal and interstitial brachytherapy with 4Gy x 2 Fractions with one week interval for those had gross residual disease far from 1cm of rectal wall. All patients underwent surgery within 4-8 week after completion of neoadjuvant therapy. In the control group which were not randomized, twenty-eight patients underwent neoadjuvant chemoradiation (45Gy in 25 Fraction with concurrent capecitabine 800mg/m2 twice daily for 5 days per week) followed by surgery. It was found that in HDR-BT group pathologic complete response (pCR), pathologic partial response (pPR) and pathologic response rates (pCR+pPR) based on AJCC TNM staging for colorectal cancer were %35.7, %35.7, and %71.4 respectively. The pCR, pPR, and pRR were %25, %17, and %42 in the control group respectively. pCR, pPR, and pRR were improved with HDR-BT. However, only response rate improvement was statistically significant (p=0.031). There was no a statistically significant difference in the complications between the two groups (p > 0.05). So it can be concluded that HDR intraluminal with or without interstitial brachytherapy may be an effective method of dose escalation technique in neoadjuvant chemoradiation therapy of locally advanced rectal cancer with higher response rate and manageable side effects.
Dosimetric Consequences of Intrafraction Variation of Tumor Motion in Lung St...semualkaira
The purpose of this study was to investigate the target dose discrepancy caused by intrafraction variation during Stereotactic Body Radiotherapy (SBRT) for lung cancer. Intensity-Modulated Radiation Therapy (IMRT) plans were designed based on Average Computed Tomography (AVG CT) utilizing the Planning Target Volume (PTV) surrounding the 65% and 85% prescription isodoses in both phantom and patient cases
Dosimetric Consequences of Intrafraction Variation of Tumor Motion in Lung St...semualkaira
The purpose of this study was to investigate the target dose discrepancy caused by intrafraction variation during Stereotactic Body Radiotherapy (SBRT) for lung cancer. Intensity-Modulated Radiation Therapy (IMRT) plans were designed based on Average Computed Tomography (AVG CT) utilizing the Planning Target Volume (PTV) surrounding the 65% and 85% prescription isodoses in both phantom and patient cases. Intrafraction variation was simulated by shifting the nominal plan isocenter along six directions from 0.5 mm to 4.5 mm with a 1-mm step size to produce a series of perturbed plans. The dose discrepancy between the initial plan and the perturbed plans was calculated as the percentage of the initial plan
Dosimetric Consequences of Intrafraction Variation of Tumor Motion in Lung St...semualkaira
The purpose of this study was to investigate the target dose discrepancy caused by intrafraction variation during Stereotactic Body Radiotherapy (SBRT) for lung cancer. Intensity-Modulated Radiation Therapy (IMRT) plans were designed based on Average Computed Tomography (AVG CT) utilizing the Planning Target Volume (PTV) surrounding the 65% and 85% prescription isodoses in both phantom and patient cases. Intrafraction variation was simulated by shifting the nominal plan isocenter along six directions from 0.5 mm to 4.5 mm with a 1-mm step size to produce a series of perturbed plans. The dose discrepancy between the initial plan and the perturbed plans was calculated as the percentage of the initial plan. Dose indices, including D99 and D95 for Internal Target Volume (ITV) and Gross Tumor Volume (GTV), were adopted as endpoint samples. The mean dose discrepancy was calculated under the 3-dimensional space distribution. In this study, we found that intrafraction motion can lead to serious dose degradation of the target and ITV in lung SBRT, especially during SBRT with PTV surrounding the lower isodose line. This phenomenon was compromised when 3-dimensional space distribution was considered. This result may provide a prospective reference for target dose degradation due to intrafraction motion during lung SBRT treatment.
Upper Rectal Cancer: Benefit After Preoperative Chemoradiation Versus Upfront...daranisaha
Upper rectal cancer management is controversial. The present series reports the outcomes of treatment comparing neoadjuvant chemoradiation (NCRT) versus upfront surgery.
Upper Rectal Cancer: Benefit After Preoperative Chemoradiation Versus Upfront...JohnJulie1
Upper rectal cancer management is controversial. The present series reports the outcomes of treatment comparing neoadjuvant chemoradiation (NCRT) versus upfront surgery.
Upper Rectal Cancer: Benefit After Preoperative Chemoradiation Versus Upfront...eshaasini
Upper rectal cancer management is controversial. The present series reports the outcomes of treatment comparing neoadjuvant chemoradiation (NCRT) versus upfront surgery.
Upper Rectal Cancer: Benefit After Preoperative Chemoradiation Versus Upfront...semualkaira
Upper rectal cancer management is controversial. The present series reports the outcomes of treatment comparing neoadjuvant chemoradiation (NCRT) versus upfront surgery.
Upper Rectal Cancer: Benefit After Preoperative Chemoradiation Versus Upfront...NainaAnon
Upper rectal cancer management is controversial. The present series reports the outcomes of treatment comparing neoadjuvant chemoradiation (NCRT) versus upfront surgery.
Clinics of Oncology | Oncology Journals | Open Access JournalEditorSara
Clinics of OncologyTM (ISSN 2640-1037) - Impact Factor 1.920* is a medical specialty that focuses on the use of operative techniques to investigate and resolve certain medical conditions caused by disease or traumatic injury.
Upper Rectal Cancer: Benefit After Preoperative Chemoradiation Versus Upfront...semualkaira
In this retrospective study we enrolled patients with upper rectal or sigmoid junction locally advanced tumors (stages II-III). At the first Institution patients received NCRT followed by surgery (study group); at the second Institution patients were referred to upfront surgery (control group). Overall survival was the main endpoint of the analysis. Local relapse and other clinical variables were also analyzed.
Breast conserving surgery followed by adjuvant radiotherapy is adopted in the early detected cases and mastectomy followed by radiotherapy or chemotherapy in the advanced cases are the general practices.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
2. target coverage, IMRT is superior to conventional techniques in
normal tissue sparing for the treatment of cervical cancer, with lower
gastrointestinal, genitourinary, and bone marrow toxicity [7–11].
Whole-pelvic step-and-shoot (SaS) IMRT for cervical cancer patients
has been used in our center since 2007. A newer technique for deli-
vering IMRT, helical tomotherapy™ (HT) (using a continuously
rotating beam), can provide highly conformal dose distributions and
simultaneous critical organ-sparing ability [12, 13]. It is being studied
for use in gynecologic malignancies and thus far has provided promis-
ing results with respect to reliable set-up accuracy and a reduction in
planning margin [14]. In our center, SaS-IMRT started in the year
2007, and HT (TomoTherapy Hi-Art with treatment planning
system (TPS) Hi- Art version 4.2.1) commenced in 2012. We use
both techniques in our practice. This is the first dosimetric compari-
son study of the two techniques in WPRT for locally advanced cer-
vical cancer in our country.
MATERIALS AND METHODS
A total of 20 cervical cancer patients who received whole-pelvis irradi-
ation with the SaS-IMRT technique at the Division of Therapeutic
Radiology and Oncology, Chiang Mai University, between January
2011 and January 2014 were retrospectively identified.
For IMRT planning, a computed tomography (CT) simulation
was performed. Vac-Loc was used to immobilize patients in position.
To prepare the bladder, patients were advised to urinate 20 min
before scanning and to drink 200 ml of water after voiding. Patients
were then set up in CT. For rectal preparation, a laxative was adminis-
tered in case of rectal dilatation. This protocol was used during irradi-
ation to maintain bladder and rectal volume. With the patients in
supine treatment position and legs relaxed on the table, the pelvic
region from the L1–L2 interspace and covering the whole vagina was
scanned without intravenous contrast to obtain appropriate images.
The CT slice thickness was 5 mm (no interslice gap). In our center,
we have only one 12-year-old CT-simulator unit, which has a single
slice thickness for IMRT planning (Toshiba: Asteion). To preserve
the machine, a 5-mm slice thickness was selected (for a large volume
site such as for pelvic irradiation).
After imaging was completed, image data was sent for contouring
(Oncentra Masterplan®, Nucletron, an Elekta company, Elekta AB,
Stockholm, Sweden) and planning (KonRad treatment planning soft-
ware®, Siemens, Concord, CA, USA).
The RTOG/JCOG recommendations were used in combination
as a guide for contouring the clinical target volume (CTV) [15–18].
The CTV was composed of the cervix, uterus, adnexae, upper half of
the vagina, and pelvic lymph nodes (common iliac lymph nodes
(LNs), external iliac LNs, internal iliac LNs, obturator LNs and presa-
cral LNs). The PTV was defined as the CTV plus a 0.7-cm margin
(for the pelvic lymph nodes) and a 1–1.5-cm margin (for the
primary cervical tumor). The bladder, rectum, sigmoid colon, small
bowel and heads of femurs were contoured as organs at risk (OARs).
For the PTV, the dose of 1.8–2 Gy per fraction at five fractions per
week was prescribed (i.e. a total dose of 45–46 Gy). The D95 (dose
to 95% of the volume) of the PTV was calculated. Additional to the
doses to 5% of the bladder, rectum and small bowel, the maximal
doses to the heads of the femurs were also evaluated. As described
earlier, patients were advised to prepare the bladder and rectum for
treatment as for the CT simulation. An electronic portal imaging
device (EPID) was used weekly to evaluate and make corrections to
positioning.
An SaS-IMRT plan was generated for each patient using KonRad,
Siemens TPS, with seven coplanar step-and-shoot beams at fixed
gantry angles G1 to G7. The G1 to G7 for most cases were 0, 40, 80,
125, 235, 280 and 320 degrees, respectively. For only six of the
patients, G4 and G5 were 5-degrees modified to 120 and 240
degrees, respectively. All patients received SaS-IMRT whole-pelvis
irradiation with our Siemens Primus.
A HT plan was then created using the Tomotherapy treatment-
planning system (HiArt, Tomotherapy, Tomotherapy Inc., Madison,
WI) for every patient (by the same medical physicist who planned
the SaS-IMRT). The optimization parameters of dose constraint and
overlap priority were given the same consideration in both the SaS-
IMRT plan and the HT plan.
We used the same contouring as for SaS-IMRT for plan gener-
ation. Both plans were required to use identical planning objectives
with respect to optimal PTV coverage and OAR sparing. Plans were
designed using a field width of 5 cm, a pitch of 0.287 and modulation
factor of 2.2 to 2.8. The mean setting and actual modulation factor
were 2.235 and 2.032, respectively.
Table 1. Patient characteristics
No. Age Stage Dose prescription
1 51 IIB 45 Gy/25 Fx
2 51 IIB 45 Gy/25 Fx
3 62 IIB 45 Gy/25 Fx
4 63 IIB 45 Gy/25 Fx
5 53 IIB 45 Gy/25 Fx
6 46 IIIB 45 Gy/25 Fx
7 52 IIB 45 Gy/25 Fx
8 57 IIB 45 Gy/25 Fx
9 52 IIB 45 Gy/25 Fx
10 54 IIB 45 Gy/25 Fx
11 52 IIB 45 Gy/25 Fx
12 53 IIIB 45 Gy/25 Fx
13 61 IIB 45 Gy/25 Fx
14 57 IIB 45 Gy/25 Fx
15 63 IIB 45 Gy/25 Fx
16 73 IIB 46 Gy/23 Fx
17 70 IIB 46 Gy /23 Fx
18 67 IIIB 46 Gy /23 Fx
19 53 IIB 46 Gy /23 Fx
20 72 IIB 46 Gy /23 Fx
540 • I. Chitapanarux et al.
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3. Dosimetric parameters were analyzed for each technique. D50%,
D95% and D5% of the PTV were selected. The priorities were pre-
scribed as follows: PTV, bladder, rectum, sigmoid colon, small bowel,
and head of femur. For organs-at-risk, D50% and D2% to the small
bowel, rectum and bladder were considered. The Dmax of the bilat-
eral heads of the femurs were also analyzed. To assess the uniformity
of dose distribution in the PTV, we calculated a uniformity index
(UI) from the formula UI = D5/D95, where D5 and D95 were the
minimum doses delivered to 5% and 95% of the PTVs. The ideal
value is 1, and it increases as the plan becomes less homogeneous.
We also calculated the quality of coverage, with a conformity index
(CI) that was defined as the ratio between the target volume and the
target volume that was covered by the reference isodose. A CI = 1 cor-
responds to ideal conformation. A CI > 1 indicates that the irradiated
volume is greater than the target volume. A CI < 1 indicates that the
target volume is only partially irradiated.
A direct comparison of the dosimetric parameters between SaS-
IMRT and HT was also performed (using the Wilcoxon’s matched
pairs test) to determine if there was a significant difference for any of
the parameters examined. Differences were considered statistically sig-
nificant at P < 0.05. Additionally, beam-on timtes (BOTs) (defined as
the time from first beam on until the last beam was turned off) of the
two delivery systems were also evaluated and compared. The study
was approved by our Institutional Review Board. All analyses were
performed using SPSS version 17.
RESULTS
Patient characteristics
A total of 20 women were included, with a median age of 55.5 years
(IQR, 52–63 years). All patients belonged to FIGO Stage IIB and
IIIB and received concurrent chemoradiotherapy with weekly cis-
platin at 40 mg/m2
. All of the patients were treated with WP SaS-
IMRT followed by brachytherapy or external beam radiotherapy
according to the tumor status after WPRT. Baseline patient character-
istics were shown in Table 1. The dosimetric data for SaS-IMRT and
HT are shown in Tables 2 and 3, respectively.
Table 2. The data for SaS-IMRT
No. Bladder Rectum Head of femur Bowel CTV PTV
D50
(Gy)
D2
(Gy)
D50
(Gy)
D2
(Gy)
Dmax
Lt (Gy)
Dmax
Rt (Gy)
D50
(Gy)
D2
(Gy)
Dmean
(Gy)
D98
(Gy)
CI UI D5
(Gy)
D50
(Gy)
D95
(Gy)
CI UI
1 41.2 48.5 37.2 49.2 46.9 45.1 28.5 46.2 48.0 45.2 0.981 1.103 50.1 47.5 43.4 0.925 1.155
2 44.9 47.5 41.3 47.5 45.2 45.4 30.5 44.8 47.8 45.4 0.986 1.084 49.6 47.7 44.3 0.941 1.119
3 41.4 48.2 38.3 49.0 47.4 43.6 21.9 37.6 47.8 45.1 0.981 1.107 50.1 47.5 43.9 0.938 1.141
4 42.9 48.9 37.0 48.8 44.8 41.9 28.9 41.5 48.5 45.9 0.989 1.093 50.3 48.1 44.8 0.944 1.124
5 40.5 48.0 36.6 48.6 38.3 39.0 26.3 40.0 48.1 45.8 0.986 1.094 50.1 47.7 44.5 0.942 1.128
6 41.1 48.8 43.5 50.3 42.3 40.9 31.2 46.5 48.7 46.2 0.994 1.084 50.5 48.3 44.3 0.941 1.139
7 41.3 50.3 35.9 52.0 47.4 47.7 28.6 41.8 49.8 47.0 0.999 1.095 51.9 49.6 44.9 0.949 1.156
8 40.2 51.0 40.6 50.8 48.0 48.0 24.9 41.8 49.5 46.2 0.998 1.108 51.8 49.1 45.0 0.951 1.152
9 48.0 50.8 34.6 52.0 45.9 45.3 27.4 41.0 49.7 47.2 0.999 1.096 51.8 49.1 44.9 0.950 1.153
10 40.5 49.5 37.9 48.8 47.3 47.1 25.2 39.6 49.2 46.7 0.996 1.091 51.2 48.7 45.1 0.952 1.136
11 37.5 49.9 40.4 50.0 48.8 46.5 28.2 41.8 49.7 46.8 0.994 1.101 51.9 49.4 44.9 0.949 1.155
12 38.1 48.9 36.2 46.4 45.5 43.7 26.2 40.8 49.9 47.0 0.998 1.100 52.0 49.4 45.0 0.950 1.156
13 40.4 50.8 36.7 50.9 44.2 41.1 29.7 40.5 49.3 46.2 0.992 1.113 51.6 48.7 44.6 0.942 1.157
14 37.1 49.7 40.2 49.8 44.3 43.8 28.0 39.2 49.3 46.5 0.996 1.092 51.2 48.8 45.0 0.952 1.137
15 38.5 50.4 35.9 50.8 46.1 43.9 23.5 38.9 49.9 47.0 1.000 1.095 52.0 49.6 45.4 0.960 1.146
16 41.9 52.8 41.1 50.7 44.4 43.0 29.6 49.0 50.7 48.0 0.994 1.100 52.6 50.1 45.7 0.945 1.152
17 42.4 51.1 44.2 52.2 42.0 41.8 31.1 49.2 49.0 46.3 0.982 1.111 51.4 48.7 45.0 0.944 1.142
18 39.7 50.1 42.0 49.2 38.8 41.0 22.1 47.5 48.9 45.8 0.976 1.099 50.9 48.6 45.0 0.942 1.131
19 44.4 49.9 41.3 48.8 42.3 42.6 22.9 48.6 49.0 45.2 0.967 1.113 51.3 48.7 44.9 0.938 1.144
20 42.2 50.3 37.9 48.8 44.1 42.0 29.4 49.2 48.9 46.5 0.982 1.093 50.9 58.5 45.6 0.947 1.117
SaS-IMRT vs tomotherapy in cervical cancer • 541
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4. Target coverage
The dosimetric parameters for the HT and IMRT plans were ana-
lyzed (Table 4). Dose distribution in all SaS-IMRT and HT plans
for all 20 patients satisfied clinical requirements. The dose distribu-
tions for SaS-IMRT and HT planned for one patient are shown in
Fig 1. HT planning demonstrated a Dmean and D98% closer to the
prescription dose than SaS-IMRT planning, with a P-value of
< 0.001 and 0.008, respectively. All the PTV dosimetric parameters
(D5%, D50% and D95%) of the HT plan were of significantly better
quality than for the IMRT plan. The dose conformity and the CI did
not differ between the plans, but the target dose UI of the HT plan
was significantly better than that of the SaS-IMRT plan.
OARs
HT showed better OAR dose sparing than SaS-IMRT. For the radi-
ation dose to the bladder and rectum, the D50% and D2% of HT
planning were both significantly less than for the SaS-IMRT plan
(P-value < 0.001). Regarding the dose to the small bowel, D50%
for the HT plan was also statistically less than for the SaS-IMRT plan
(P-value < 0.001). However, we did not find a statistically significant
difference in D2% for the small bowel when comparing the two tech-
niques. The Dmax of the head of the left femur was (statistically sig-
nificantly) lower in the HT plan, whereas there was no difference for
the head of the right femur between the two techniques. The dose
statistics of the OARs are also listed in Table 4.
Beam-on time
The median BOT was significantly shorter in HT delivery (230.6 s)
than in SaS-IMRT delivery (900.0 s), with a P-value of < 0.001.
DISCUSSION
For the treatment of cervical cancer, WPRT has been used for more
than five decades. The conventional two- or four-field box techniques
were applied to the target, which was composed of the primary site
and the pelvic LNs. Although this simple technique yielded good
treatment results and acceptable toxicity, the OARs still received
Table 3. The data for HT
No. Bladder Rectum Head of femur Bowel CTV PTV
D50
(Gy)
D2
(Gy)
D50
(Gy)
D2
(Gy)
Dmax
Lt (Gy)
Dmax
Rt (Gy)
D50
(Gy)
D2
(Gy)
Dmean
(Gy)
D98
(Gy)
CI UI D5
(Gy)
D50
(Gy)
D95
(Gy)
CI UI
1 34.3 45.3 33.9 46.5 41.1 41.5 24.1 45.1 46.1 45.3 0.995 1.028 46.7 46.0 44.8 0.942 1.042
2 43.9 46.0 39.6 46.7 44.7 45.8 27.2 45.3 46.3 45.4 0.992 1.028 46.8 46.2 44.9 0.949 1.042
3 36.6 46.8 39.2 46.7 44.3 43.5 21.0 40.4 46.6 45.4 0.987 1.029 47.3 46.5 44.8 0.942 1.056
4 38.7 47.1 32.7 46.1 43.0 42.8 26.6 42.3 46.5 45.5 0.990 1.029 47.0 46.4 44.9 0.950 1.047
5 38.2 46.8 34.0 45.7 43.8 42.0 25.9 41.4 47.2 46.0 0.994 1.034 47.8 47.1 45.0 0.950 1.062
6 38.8 46.2 41.4 47.3 43.7 43.4 23.7 45.4 46.4 45.3 0.989 1.032 47.0 46.3 44.6 0.940 1.054
7 41.3 46.8 33.8 46.7 45.1 44.4 26.3 41.1 46.4 45.7 0.999 1.026 47.0 46.3 45.1 0.956 1.042
8 37.1 46.4 38.2 46.4 44.7 44.7 24.1 40.3 46.2 45.2 0.992 1.028 46.8 46.1 45.0 0.950 1.040
9 44.8 46.6 33.7 46.9 44.7 43.9 26.0 40.6 46.4 45.6 0.992 1.027 47.0 46.3 45.1 0.951 1.042
10 36.7 46.5 31.5 46.6 43.7 43.5 22.7 41.8 46.4 45.6 0.999 1.025 46.9 46.2 44.9 0.946 1.045
11 38.3 47.0 38.6 47.6 44.3 44.2 26.6 40.9 46.7 45.9 0.997 1.027 47.2 46.6 44.9 0.946 1.051
12 36.1 46.6 35.9 46.2 42.0 42.6 23.7 44.3 46.3 45.4 0.994 1.027 46.8 46.1 44.9 0.950 1.042
13 38.7 46.8 35.3 46.3 44.0 43.1 27.2 41.9 46.5 45.7 0.999 1.026 47.0 46.3 44.8 0.947 1.049
14 38.4 46.3 36.2 46.6 43.6 42.8 26.0 41.1 46.3 45.4 0.996 1.027 46.9 46.2 44.9 0.949 1.045
15 38.1 46.6 34.1 46.2 43.0 43.3 21.0 40.7 46.0 45.2 0.995 1.025 46.6 46.0 44.9 0.944 1.038
16 35.5 47.7 38.8 49 42.0 44.1 28.6 47.5 47.0 46.3 0.991 1.035 48.0 47.2 45.8 0.948 1.048
17 30.1 47.9 40.6 48.1 39.9 40.2 30.1 47.5 47.4 46.7 1.000 1.024 48.1 47.5 46.0 0.951 1.046
18 33.3 47.1 35.4 47.5 42.0 40.8 18.6 46.1 47.0 46.4 0.997 1.025 47.8 46.9 45.7 0.942 1.046
19 42.7 47.8 37.2 47.8 41.0 41.7 20.3 46.7 46.9 46.0 0.985 1.032 47.8 46.9 45.9 0.949 1.041
20 31.7 47.4 30.8 45.4 44.7 43.6 24.3 47.3 47.0 46.2 1.000 1.027 47.6 46.9 45.9 0.946 1.037
542 • I. Chitapanarux et al.
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5. significant dosages, even with good blocking. With new techniques of
imaging (CT or MRI) and planning, the possibility of keeping the
target dose high and reducing the dose to the OARs has become a
reality. After the first publication concerning the use of IMRT in
gynecological cancers by Portelance et al. [7], the use of high-tech-
nology radiation therapy soon became more prevalent. Most studies
have reported the benefits of IMRT in reducing the dose to OARs in
radical and postoperative settings. [6, 7, 19–22].
Moreover, the supported study from Cancer Care Ontario
reported comparative clinical outcomes for three dimension con-
formal radiotherapy (3DCRT) and IMRT. This report supported the
use of IMRT in the treatment of gynecologic cancers in order to
reduce the toxicity of the treatment. However, this group warned that
clinicians should be aware of the uncertainties involved and be judi-
cious in the use of gynecologic IMRT with the primary goal of redu-
cing toxicity [23]. The development of intensity-modulated arc
therapy (IMAT) was the next area of advancement in technique. The
new variation of dynamic-IMRT allowed 360° treatment. HT, volu-
metric-modulated arc therapy (VMAT™) and RAPID arc™ are all
IMAT technologies that were developed to improve treatment quality
compared with conventional IMRT. Indeed, a promising trend has
been observed, demonstrating IMAT provides better dose distribu-
tions and CIs with shorter BOTs when compared with conventional
IMRT [24–26].
Table 4. Wilcoxon matched pairs test between the two treatment plans
Structure DVH criteria Tomotherapy median (IQR) SaS-IMRT median (IQR) P-value
Age 55.50 (52.00–63.00)
Bladder D50 38.15 (35.80–38.75) 41.15 (39.95–42.30) <0.001
D2 46.80 (46.45–47.10) 49.90 (48.85–50.60) <0.001
Rectum D50 35.65 (33.85–38.70) 38.10 (36.65–41.20) <0.001
D2 46.65 (46.25–47.40) 49.50 (48.80–50.80) <0.001
Small bowel D50 25.10 (23.20–26.60) 28.10 (25.05–29.50) <0.001
D2 42.10 (41.00–45.75) 41.80 (40.25–47.00) 0.823
Head of femur Dmax Left 43.70 (42.00–44.60) 45.00 (42.75–47.20) 0.021
Dmax Right 43.35 (42.15–44.05) 43.65 (41.82–45.38) 0.225
CTV Dmean 46.45 (46.30–46.95) 49.10 (48.60–49.70) <0.001
D98 45.60 (45.40–46.00) 46.25 (45.80–46.90) 0.008
CI 0.99 (0.99–1.00) 0.99 (0.98–1.00) 0.057
UI 1.03 (1.03–1.03) 1.10 (1.09–1.10) <0.001
PTV D5 47.0 (46.8–47.75) 51.25 (50.35–51.88) <0.001
D50 46.30 (46.20–46.90) 48.70 (48.15–49.40) <0.001
D95 44.90 (44.90–45.55) 44.90 (44.53–45.00) <0.001
CI 0.95 (9.94–0.95) 0.94 (0.94–9.95) 0.093
UI 1.05 (1.04–1.05) 1.14 (1.13–1.15) <0.001
Beam-on time 230.6 (217.4–240.1) 900.0 (840.0–904.0 <0.001
Fig. 1. Dose distribution for SAS-IMRT (left) and HT (right) plan.
SaS-IMRT vs tomotherapy in cervical cancer • 543
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6. This study provides a dosimetric analysis of SaS-IMRT and HT to
assess optimal treatment planning for pelvic irradiation in locally
advanced cervical cancer. We performed the comparative planning
studies by independently optimizing planning in the same patient.
Our results indicate that HT had better conformal CTV and PTV
coverage and sparing of OARs than did SaS-IMRT, as shown in
Table 4. HT demonstrated a 3 Gy lower median dose at D2% of the
bladder and rectum with statistically significant differences. HT did
demonstrate a 1 Gy higher dose Dmean of the small bowel, which
was concerning, although it was not significant statistically. HT was of
clear benefit in lowering the cumulative bladder and rectal dose when
compared with brachytherapy. All the PTV dosimetric parameters
(D5%, D50% and D95%) for the HT plan were of significantly better
quality than for the IMRT plan. Although the D98 of the CTV had a
1-Gy difference (45.6 versus 46.27; P = 0.008), the UI of HT was
significantly closer to 1 than SaS-IMRT (P < 0.001) with the same
CI (0.99). This demonstrates a lower overdose region for treatment
by HT. After much discussion between radiation oncologists and
medical physicists in our center, we have just this year changed the
plan evaluation from D95 to D50 of the PTV, as per ICRU 83. So,
D95 of the PTV was the main evaluation for the target, but we evalu-
ated additional parameters as per ICRU 83 [27] recommendations.
Although the median dose at D95 of the PTV had statistical signifi-
cance, all plans achieved the target dose to D95 of the PTV, and HT
planning showed better UI and less data deviation than SaS-IMRT.
Moreover, our findings suggest that using HT will have a favorable
impact on BOT.
Another limitation in using pelvic SaS-IMRT for cervical cancer is
organ motion, which is not evaluated prior to treatment delivery.
This would be another advantage of using HT: using megavoltage
CT before each treatment session, thus allowing the plan to have
smaller margins as well as lower radiation exposure to nearby OARs
because of improved set-up accuracy and reproducibility.
CONCLUSION
When treating cervical cancer with IMRT, HT provided a distinct
advantage compared with SaS-IMRT with respect to target coverage
and OARs. Moreover, it had shorter delivery treatment time.
ACKNOWLEDGEMENTS
The authors offer many thanks to the staff of the NRU–CMU in the
Gynecologic Oncology Cluster and the Division of Therapeutic Radi-
ology and Oncology, Faculty of Medicine, Chiang Mai University, for
supporting this study.
CONFLICT OF INTEREST
The authors have declared that there are no conflicts of interest.
FUNDING
Funding by Faculty of Medicine, Chiang Mai University. Funding to
pay the Open Access publication charges for this article was provided
by Faculty of Medicine, Chiang Mai University.
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