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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: 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%.

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.

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The summed dose profile at isocenter of two dynamic matching field edges with a 3 cm leaf motion and a 5.5 cm overlap at treatment distance. Field 1 was measured at depth of 10 cm and field 2 was the inverse of field 1 in position.
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fig7: The summed dose profile at isocenter of two dynamic matching field edges with a 3 cm leaf motion and a 5.5 cm overlap at treatment distance. Field 1 was measured at depth of 10 cm and field 2 was the inverse of field 1 in position.

Mentions: Figure 7 shows the combined dose profile of two matched dynamic field edges with a 5.5 cm overlap. Field 1 was measured at a depth of 10 cm with 3 cm of leaf motion, and field 2 was the reverse of the field 1 in terms of position. The dose variation in the overlapped region ranged from 102.2% to 106.1% with the dose normalized to detector No. 40.


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 summed dose profile at isocenter of two dynamic matching field edges with a 3 cm leaf motion and a 5.5 cm overlap at treatment distance. Field 1 was measured at depth of 10 cm and field 2 was the inverse of field 1 in position.
© Copyright Policy
Related In: Results  -  Collection

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

fig7: The summed dose profile at isocenter of two dynamic matching field edges with a 3 cm leaf motion and a 5.5 cm overlap at treatment distance. Field 1 was measured at depth of 10 cm and field 2 was the inverse of field 1 in position.
Mentions: Figure 7 shows the combined dose profile of two matched dynamic field edges with a 5.5 cm overlap. Field 1 was measured at a depth of 10 cm with 3 cm of leaf motion, and field 2 was the reverse of the field 1 in terms of position. The dose variation in the overlapped region ranged from 102.2% to 106.1% with the dose normalized to detector No. 40.

Bottom Line: 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%.

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