Analysis of modulation factor to shorten the delivery time in helical tomotherapy

Helical tomotherapy (HT) can be used for the delivery of cranio-spinal axis irradiation (CSAI) without the need for beam matching of conventional linac-based external beam irradiation. The aim of this study is to retrospectively evaluate HT plans used for treatment in nine patients treated with CSAI. Helical tomotherapy cranio-spinal axis irradiation (HT-CSAI) plans were created for each patient. Average length along the cranio-spinal axis of the PTV was 65.6 cm with a range between 53 and 74 cm. Treatment planning optimization and plan evaluation parameters were obtained from the HT planning station for each of the nine patients. PTV coverage by the 95% isodose surface ranged between 98.0 to 100.0% for all nine patients. The clinically acceptable dose variation within the PTV or tolerance range was between 0.7 and 2.5% for all nine patients. Doses to the organs at risk were clinically acceptable. An increasing length along the longitudinal axis of the PTV did not consistently increase the beam-on time indicating that using a larger jaw width had a greater impact on treatment time. With a larger jaw width it is possible to substantially reduce the normalized beam-on treatment time without compromising plan quality and sparing of organs at risk. By using a larger jaw width or lower modulation factor or both, normalized beam-on times were decreased by up to 61% as compared to the other evaluated treatment plans. From the nine cases reported in this study the minimum beam-on time was achieved with a jaw width of 5.0 cm, pitch of 0.287 and a modulation factor of 2.0. Large and long cylindrical volumes can be effectively treated with helical tomotherapy with both clinically acceptable dose distribution and beam-on time.

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SU-FF-T-421: The Influence of Field Length, Pitch, and Modulation Factor On the Quality of Helical Tomotherapy Plans

Medical Physics ◽

10.1118/1.2241340 ◽

2006 ◽

Vol 33 (6Part13) ◽

pp. 2142-2143

Author(s):

C Bhavin ◽

K Langen ◽

S Meeks ◽

O Zeidan ◽

S Jeswani

Keyword(s):

Helical Tomotherapy ◽

Modulation Factor

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Investigation of Pitch and Jaw Width to Decrease Delivery Time of Helical Tomotherapy Treatments for Head and Neck Cancer

Medical Dosimetry ◽

10.1016/j.meddos.2010.10.001 ◽

2011 ◽

Vol 36 (4) ◽

pp. 397-403 ◽

Cited By ~ 8

Author(s):

Monica Moldovan ◽

Jonas D. Fontenot ◽

John P. Gibbons ◽

Tae Kyu Lee ◽

Isaac I. Rosen ◽

...

Keyword(s):

Head And Neck Cancer ◽

Head And Neck ◽

Neck Cancer ◽

Helical Tomotherapy ◽

Delivery Time

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EP-1407: Quality Assurance on Helical Tomotherapy Treatments with small target and high modulation factor using ArcCHECK

Radiotherapy and Oncology ◽

10.1016/s0167-8140(15)41399-4 ◽

2015 ◽

Vol 115 ◽

pp. S759

Author(s):

C.W. Kong ◽

Y.W. Ho ◽

H. Geng ◽

W.W. Lam ◽

T.L. Chiu ◽

...

Keyword(s):

Quality Assurance ◽

Helical Tomotherapy ◽

Small Target ◽

Modulation Factor ◽

High Modulation

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Helical Tomotherapy for Skull Base Tumors: A Preliminary Report

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0034-1384186 ◽

2014 ◽

Vol 75 (S 02) ◽

Author(s):

Wan-Soo Yoon ◽

D. Chung

Keyword(s):

Skull Base ◽

Preliminary Report ◽

Helical Tomotherapy ◽

Skull Base Tumors

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Penjadwalan Produksi Menggunakan Metode Simulated Annealing pada Unit Produksi Daun Pintu di PT. ML

Talenta Conference Series Energy and Engineering (EE) ◽

10.32734/ee.v2i2.445 ◽

2019 ◽

Vol 2 (2) ◽

Author(s):

Rosnani Ginting ◽

Chairul Rahmadsyah Manik

Keyword(s):

Simulated Annealing ◽

Problem Solving ◽

Production Scheduling ◽

Production Control ◽

Delivery Time ◽

Production Schedule ◽

A Company ◽

Predetermined Time ◽

Factory Floor

Penjadwalan merupakan aspek yang sangat penting karena didalamnya terdapat elemen perencanaan dan pengendalian produksi bagi suatu perusahaan yang dapat mengirim barang sesuai dengan waktu yang telah ditentukan, untuk memperoleh waktu total penyelesaian yang minimum. Masalah utama yang dihadapi oleh PT. ML adalah keterlambatan penyelesaian order yang mempengaruhi delivery time ke tangan costumer karena pelaksanaan penjadwalan produksi dilantai pabrik belum menghasilkan makespan yang sesuai dengan order yang ada. Oleh kaena itu dituntut untuk mencari solusi pemecahan masalah optimal dalam penentuan jadwal produksi untuk meminimisasi total waktu penyelessaian (makespan) semua order. Dalam penelitian ini, penjadwalan menggunakan metode Simulated Annealing (SA) diharapkan dapat menghasilkan waktu total penyelesaian lebih cepat dari penjadwalan yang ada pada perusahaan. Scheduling is a very important aspect because in it there are elements of planning and production control for a company that can send goods in accordance with a predetermined time, to obtain a minimum total time of completion. The main problem faced by PT. ML is the delay in completing orders that affect delivery time to customer because the implementation of production scheduling on the factory floor has not produced the makespan that matches the existing order. Therefore, it is required to find optimal problem solving solutions in determining the production schedule to minimize the total time of elimination (makespan) of all orders. In this study, scheduling using the Simulated Annealing (SA) method is expected to produce a total time of completion faster than the existing scheduling in the company.

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Helical tomotherapy for advanced esophageal cancer improves target conformity and homogeneity: A comparison with fixed-field intensity-modulated radiotherapy

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v11i3.471 ◽

2015 ◽

Vol 11 (3) ◽

pp. 3146-3155

Author(s):

Luhua Wang

Keyword(s):

Esophageal Cancer ◽

Field Intensity ◽

Helical Tomotherapy ◽

Intensity Modulated Radiotherapy ◽

Matched Pair ◽

Conformity Index ◽

Target Coverage ◽

Advanced Esophageal Cancer ◽

Fixed Field ◽

Intensity Modulated

Purpose: To evaluate the usefulness of helical tomotherapy (HT) in the treatment of advanced esophageal cancer (EC) and compare target homogeneity, conformity and normal tissue doses between HT and fixed-field intensity-modulated radiotherapy (ff-IMRT).Methods: In all, 23 patients with cT3-4N0-1M0-1a thoracic EC (upper esophagus, 9 patients; middle esophagus, 6; distal esophagus, 6 and esophagogastric junction, 2) who were treated with ff-IMRT (60 Gy in 30 fractions) were re-planned for HT and ff-IMRT with the same clinical requireÂments. Comparisons were performed using the Wilcoxon matched-pair signed-rank test.Results: Compared with ff-IMRT, HT significantly reduced the homogeneity index for thoracic, upper, middle and distal ECs by 38%, 31%, 36% and 33%, respectively (P < 0.05). The conformity index was increased by HT for thoracic, upper and middle ECs by 9%, 9% and 18%, respectively (P < 0.05). Target coverage was improved by 1% with HT (P < 0.05). The mean lung dose was significantly reduced by HT for thoracic and upper ECs (P < 0.05). The V20 (volume receiving at least 20 Gy) and higher dose volumes of the lungs were decreased by HT in all cases, but the differences were significant for thoracic, upper and distal ECs (P < 0.05), with reductions of 2.1%, 3.1% and 2.2%, respectively. HT resulted in a larger lung V5 for thoracic, upper, middle and distal ECs, with increases of 3.5%, 1.5%, 7.2% and 3.2%, respectively. Heart sparing was significantly better with HT than with ff-IMRT in terms of the V30 and V40 for thoracic, upper, middle and distal ECs (P < 0.05).Conclusions: Compared to ff-IMRT, HT provides superior target coverage, conformity and homogeneity, with reduced the volume of high doses to the lungs and heart for advanced EC. HT may be a treatment option for advanced EC, especially upper EC.

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