SU‐FF‐T‐250

Impact of Pulse Forming Network (PFN) and Injection Current (IC) Parameters On Output and Energy Variations of Helical TomoTherapy

C. Shi, A. Gutiérrez, Y. Liu, Y. Zhai, Nikos Papanikolaou

Research output: Contribution to journalArticle

Abstract

Purpose: To quantity evaluate the impact of pulse forming network (PFN) and injection current (IC) parameters on the output and energy variations of a helical TomoTherapy (HT) unit. Method and Materials: Tomotherapy quality assurance (TQA™) platform, especially the step wedge phantom and step wedge static module, was used for the whole measurement. PFN and IC voltage values were coarsely sampled from 3.0 to 5.0 V in 0.2 V increments, and finely sampled ([formula omitted] and [formula omitted]) in 0.02 V increments. Results: Five working zones were found for different combination of PFN and IC voltage values: low dose rate zone, normal dose rate zone, dose rate failure during treatment zone, high dose rate zone, inoperable dose rate zone. It was noted that a 1.0% increase in VIC yields an average 1.4% increase in the average dose rate. Additionally, a 0.02 V increase in VPFN yields an average 1.0% increase in the average dose rate. A 1.0% increase in the VIC value yielded an average 0.3% decrease in the energy ratio. Furthermore, changes in the energy ratio were more dependent on VIC than VPFN based on the fact that only a 0.5% variation in energy was noted when varying the VPFN from 4.00 to 4.10 V while a 2.0% change was noted when varying the VIC from 3.5 to 3.7 V. Conclusions: In this study, several working zones based on the VPFN and VIC parameter setting were found to exist for a HT unit. Inside the normal dose rate zone, the output and energy vary linearly with VIC and VPFN parameter values. The results of this study may provide a quick guide for physicists to adjust their HT unit VPFN and VIC values in order to reset the radiation beam output and energy back to within the tolerance of the commissioned baseline.

Original languageEnglish (US)
Pages (from-to)2578
Number of pages1
JournalMedical Physics
Volume36
Issue number6
DOIs
StatePublished - 2009

Fingerprint

Intensity-Modulated Radiotherapy
Injections
Treatment Failure
Radiation

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

Cite this

SU‐FF‐T‐250 : Impact of Pulse Forming Network (PFN) and Injection Current (IC) Parameters On Output and Energy Variations of Helical TomoTherapy. / Shi, C.; Gutiérrez, A.; Liu, Y.; Zhai, Y.; Papanikolaou, Nikos.

In: Medical Physics, Vol. 36, No. 6, 2009, p. 2578.

Research output: Contribution to journalArticle

@article{f44d8100ec254b49a134a7cb3a26d52a,
title = "SU‐FF‐T‐250: Impact of Pulse Forming Network (PFN) and Injection Current (IC) Parameters On Output and Energy Variations of Helical TomoTherapy",
abstract = "Purpose: To quantity evaluate the impact of pulse forming network (PFN) and injection current (IC) parameters on the output and energy variations of a helical TomoTherapy (HT) unit. Method and Materials: Tomotherapy quality assurance (TQA™) platform, especially the step wedge phantom and step wedge static module, was used for the whole measurement. PFN and IC voltage values were coarsely sampled from 3.0 to 5.0 V in 0.2 V increments, and finely sampled ([formula omitted] and [formula omitted]) in 0.02 V increments. Results: Five working zones were found for different combination of PFN and IC voltage values: low dose rate zone, normal dose rate zone, dose rate failure during treatment zone, high dose rate zone, inoperable dose rate zone. It was noted that a 1.0{\%} increase in VIC yields an average 1.4{\%} increase in the average dose rate. Additionally, a 0.02 V increase in VPFN yields an average 1.0{\%} increase in the average dose rate. A 1.0{\%} increase in the VIC value yielded an average 0.3{\%} decrease in the energy ratio. Furthermore, changes in the energy ratio were more dependent on VIC than VPFN based on the fact that only a 0.5{\%} variation in energy was noted when varying the VPFN from 4.00 to 4.10 V while a 2.0{\%} change was noted when varying the VIC from 3.5 to 3.7 V. Conclusions: In this study, several working zones based on the VPFN and VIC parameter setting were found to exist for a HT unit. Inside the normal dose rate zone, the output and energy vary linearly with VIC and VPFN parameter values. The results of this study may provide a quick guide for physicists to adjust their HT unit VPFN and VIC values in order to reset the radiation beam output and energy back to within the tolerance of the commissioned baseline.",
author = "C. Shi and A. Guti{\'e}rrez and Y. Liu and Y. Zhai and Nikos Papanikolaou",
year = "2009",
doi = "10.1118/1.3181726",
language = "English (US)",
volume = "36",
pages = "2578",
journal = "Medical Physics",
issn = "0094-2405",
publisher = "AAPM - American Association of Physicists in Medicine",
number = "6",

}

TY - JOUR

T1 - SU‐FF‐T‐250

T2 - Impact of Pulse Forming Network (PFN) and Injection Current (IC) Parameters On Output and Energy Variations of Helical TomoTherapy

AU - Shi, C.

AU - Gutiérrez, A.

AU - Liu, Y.

AU - Zhai, Y.

AU - Papanikolaou, Nikos

PY - 2009

Y1 - 2009

N2 - Purpose: To quantity evaluate the impact of pulse forming network (PFN) and injection current (IC) parameters on the output and energy variations of a helical TomoTherapy (HT) unit. Method and Materials: Tomotherapy quality assurance (TQA™) platform, especially the step wedge phantom and step wedge static module, was used for the whole measurement. PFN and IC voltage values were coarsely sampled from 3.0 to 5.0 V in 0.2 V increments, and finely sampled ([formula omitted] and [formula omitted]) in 0.02 V increments. Results: Five working zones were found for different combination of PFN and IC voltage values: low dose rate zone, normal dose rate zone, dose rate failure during treatment zone, high dose rate zone, inoperable dose rate zone. It was noted that a 1.0% increase in VIC yields an average 1.4% increase in the average dose rate. Additionally, a 0.02 V increase in VPFN yields an average 1.0% increase in the average dose rate. A 1.0% increase in the VIC value yielded an average 0.3% decrease in the energy ratio. Furthermore, changes in the energy ratio were more dependent on VIC than VPFN based on the fact that only a 0.5% variation in energy was noted when varying the VPFN from 4.00 to 4.10 V while a 2.0% change was noted when varying the VIC from 3.5 to 3.7 V. Conclusions: In this study, several working zones based on the VPFN and VIC parameter setting were found to exist for a HT unit. Inside the normal dose rate zone, the output and energy vary linearly with VIC and VPFN parameter values. The results of this study may provide a quick guide for physicists to adjust their HT unit VPFN and VIC values in order to reset the radiation beam output and energy back to within the tolerance of the commissioned baseline.

AB - Purpose: To quantity evaluate the impact of pulse forming network (PFN) and injection current (IC) parameters on the output and energy variations of a helical TomoTherapy (HT) unit. Method and Materials: Tomotherapy quality assurance (TQA™) platform, especially the step wedge phantom and step wedge static module, was used for the whole measurement. PFN and IC voltage values were coarsely sampled from 3.0 to 5.0 V in 0.2 V increments, and finely sampled ([formula omitted] and [formula omitted]) in 0.02 V increments. Results: Five working zones were found for different combination of PFN and IC voltage values: low dose rate zone, normal dose rate zone, dose rate failure during treatment zone, high dose rate zone, inoperable dose rate zone. It was noted that a 1.0% increase in VIC yields an average 1.4% increase in the average dose rate. Additionally, a 0.02 V increase in VPFN yields an average 1.0% increase in the average dose rate. A 1.0% increase in the VIC value yielded an average 0.3% decrease in the energy ratio. Furthermore, changes in the energy ratio were more dependent on VIC than VPFN based on the fact that only a 0.5% variation in energy was noted when varying the VPFN from 4.00 to 4.10 V while a 2.0% change was noted when varying the VIC from 3.5 to 3.7 V. Conclusions: In this study, several working zones based on the VPFN and VIC parameter setting were found to exist for a HT unit. Inside the normal dose rate zone, the output and energy vary linearly with VIC and VPFN parameter values. The results of this study may provide a quick guide for physicists to adjust their HT unit VPFN and VIC values in order to reset the radiation beam output and energy back to within the tolerance of the commissioned baseline.

UR - http://www.scopus.com/inward/record.url?scp=85024816324&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85024816324&partnerID=8YFLogxK

U2 - 10.1118/1.3181726

DO - 10.1118/1.3181726

M3 - Article

VL - 36

SP - 2578

JO - Medical Physics

JF - Medical Physics

SN - 0094-2405

IS - 6

ER -