Feasibility study of glass dosimeter for in vivo measurement: dosimetric characterization and clinical application in proton beams.
OBJECTIVE
To evaluate the suitability of the GD-301 glass dosimeter for in vivo dose verification in proton therapy.


METHODS
The glass dosimeter was analyzed for its dosimetrics characteristic in proton beam. Dosimeters were calibrated in a water phantom using a stairlike holder specially designed for this study. To determine the accuracy of the glass dosimeter in proton dose measurements, we compared the glass dosimeter and thermoluminescent dosimeter (TLD) dose measurements using a cylindrical phantom. We investigated the feasibility of the glass dosimeter for the measurement of dose distributions near the superficial region for proton therapy plans with a varying separation between the target volume and the surface of 6 patients.


CONCLUSIONS
Uniformity was within 1.5%. The dose-response has good linearity. Dose-rate, fading, and energy dependence were found to be within 3%. The beam profile measured using the glass dosimeter was in good agreement with the profile obtained from the ionization chamber. Depth-dose distributions in nonmodulated and modulated proton beams obtained with the glass dosimeter were estimated to be within 3%, which was lower than those with the ionization chamber. In the phantom study, the difference of isocenter dose between the delivery dose calculated by the treatment planning system and that measured by the glass dosimeter was within 5%. With in vivo dosimetry, the calculated surface doses overestimated measurements by 4%-16% using glass dosimeter and TLD.


CONCLUSIONS
It is recommended that bolus be added for these clinical cases. We also believe that the glass dosimeter has considerable potential for use with in vivo patient proton dosimetry.
Department of Radiation Oncology, Myongji Hospital, Kwandong University College of Medicine, Goyang, Korea.
Jeong-Eun
JE
Rah
Do Hoon
DH
Oh
Jong Won
JW
Kim
Dae-Hyun
DH
Kim
Tae-Suk
TS
Suh
Young Hoon
YH
Ji
Dongho
D
Shin
Se Byeong
SB
Lee
Dae Yong
DY
Kim
Sung Yong
SY
Park
D000328:Adult; D000368:Aged; D002138:Calibration; D005240:Feasibility Studies; D005260:Female; D005898:Glass; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000532:radiotherapy; D019047:Phantoms, Imaging; D061766:Proton Therapy; D011879:Radiotherapy Dosage; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation* / Q000379:methods; D035501:Uncertainty; D011522:Protons
D011522:Protons