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Total body irradiation with step translation and dynamic field matching.

Chen HH, Wu J, Chuang KS, Lin JF, Lee JC, Lin JC - Biomed Res Int (2013)

Bottom Line: The dose distribution in the overlapped region ranged from 98.5% to 102.8%.Lateral dose profiles at abdomen and head revealed 109.8% and 111.7% high doses, respectively, at the body edges.The results confirmed that the technique is capable of delivering a uniform dose distribution to the midline of the body in a small treatment room while keeping the lung dose within the tolerance level.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, Taichung Veterans General Hospital, 1650 Taiwan Boulevard Sect. 4, Taichung 40705, Taiwan.

ABSTRACT
The purpose of this study is to develop a total body irradiation technique that does not require additional devices or sophisticated processes to overcome the space limitation of a small treatment room. The technique aims to deliver a uniform dose to the entire body while keeping the lung dose within the tolerance level. The technique treats the patient lying on the floor anteriorly and posteriorly. For each AP/PA treatment, two complementary fields with dynamic field edges are matched over an overlapped region defined by the marks on the body surface. A compensator, a spoiler, and lung shielding blocks were used during the treatment. Moreover, electron beams were used to further boost the chest wall around the lungs. The technique was validated in a RANDO phantom using GAFCHROMIC films. Dose ratios at different body sites along the midline ranged from 0.945 to 1.076. The dose variation in the AP direction ranged from 96.0% to 104.6%. The dose distribution in the overlapped region ranged from 98.5% to 102.8%. Lateral dose profiles at abdomen and head revealed 109.8% and 111.7% high doses, respectively, at the body edges. The results confirmed that the technique is capable of delivering a uniform dose distribution to the midline of the body in a small treatment room while keeping the lung dose within the tolerance level.

Show MeSH
The dynamic field-edge matching technique generates a match zone by overlapping two fields along their border. Two complementary inclined fields smear the dose variations over a wide region. The field intensity profiles are shown with the fields (a) overlapping or (b) separated by a gap.
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fig2: The dynamic field-edge matching technique generates a match zone by overlapping two fields along their border. Two complementary inclined fields smear the dose variations over a wide region. The field intensity profiles are shown with the fields (a) overlapping or (b) separated by a gap.

Mentions: To deal with dose heterogeneity, a dynamic field-edge matching technique [26–28] that smears dose inhomogeneity over the field matching zone by two complementary inclined fields was used (Figure 2). In order to keep homogeneous junction dose at all depths, the matching field edges must be parallel to each other. Hence, the gantry was rotated according to the beam divergent angle to make the matching field edges aligned.


Total body irradiation with step translation and dynamic field matching.

Chen HH, Wu J, Chuang KS, Lin JF, Lee JC, Lin JC - Biomed Res Int (2013)

The dynamic field-edge matching technique generates a match zone by overlapping two fields along their border. Two complementary inclined fields smear the dose variations over a wide region. The field intensity profiles are shown with the fields (a) overlapping or (b) separated by a gap.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3713376&req=5

fig2: The dynamic field-edge matching technique generates a match zone by overlapping two fields along their border. Two complementary inclined fields smear the dose variations over a wide region. The field intensity profiles are shown with the fields (a) overlapping or (b) separated by a gap.
Mentions: To deal with dose heterogeneity, a dynamic field-edge matching technique [26–28] that smears dose inhomogeneity over the field matching zone by two complementary inclined fields was used (Figure 2). In order to keep homogeneous junction dose at all depths, the matching field edges must be parallel to each other. Hence, the gantry was rotated according to the beam divergent angle to make the matching field edges aligned.

Bottom Line: The dose distribution in the overlapped region ranged from 98.5% to 102.8%.Lateral dose profiles at abdomen and head revealed 109.8% and 111.7% high doses, respectively, at the body edges.The results confirmed that the technique is capable of delivering a uniform dose distribution to the midline of the body in a small treatment room while keeping the lung dose within the tolerance level.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, Taichung Veterans General Hospital, 1650 Taiwan Boulevard Sect. 4, Taichung 40705, Taiwan.

ABSTRACT
The purpose of this study is to develop a total body irradiation technique that does not require additional devices or sophisticated processes to overcome the space limitation of a small treatment room. The technique aims to deliver a uniform dose to the entire body while keeping the lung dose within the tolerance level. The technique treats the patient lying on the floor anteriorly and posteriorly. For each AP/PA treatment, two complementary fields with dynamic field edges are matched over an overlapped region defined by the marks on the body surface. A compensator, a spoiler, and lung shielding blocks were used during the treatment. Moreover, electron beams were used to further boost the chest wall around the lungs. The technique was validated in a RANDO phantom using GAFCHROMIC films. Dose ratios at different body sites along the midline ranged from 0.945 to 1.076. The dose variation in the AP direction ranged from 96.0% to 104.6%. The dose distribution in the overlapped region ranged from 98.5% to 102.8%. Lateral dose profiles at abdomen and head revealed 109.8% and 111.7% high doses, respectively, at the body edges. The results confirmed that the technique is capable of delivering a uniform dose distribution to the midline of the body in a small treatment room while keeping the lung dose within the tolerance level.

Show MeSH