TY  - JOUR
AU  - Candela-Juan, C.
AU  - Niatsetski, Y.
AU  - van der Laarse, R.
AU  - Granero, D.
AU  - Ballester, F.
AU  - Perez-Calatayud, J.
AU  - Vijande, J.
PY  - 2016
DA  - 2016//
TI  - Design and characterization of a new high-dose-rate brachytherapy Valencia applicator for larger skin lesions
T2  - Med. Phys.
JO  - Medical Physics
SP  - 1639
EP  - 1648
VL  - 43
IS  - 4
PB  - Amer Assoc Physicists Medicine Amer Inst Physics
KW  - skin applicator
KW  - Valencia applicator
KW  - HDR brachytherapy
KW  - dosimetry
KW  - Monte Carlo
AB  - Purpose: The aims of this study were (i) to design a new high-dose-rate (HDR) brachytherapy applicator for treating surface lesions with planning target volumes larger than 3 cm in diameter and up to 5 cm in size, using the microSelectron-HDR or Flexitron afterloader (Elekta Brachytherapy) with a Ir-192 source; (ii) to calculate by means of the Monte Carlo (MC) method the dose distribution for the new applicator when it is placed against a water phantom; and (iii) to validate experimentally the dose distributions in water. Methods: The PENELOPE2008 MC code was used to optimize dwell positions and dwell times. Next, the dose distribution in a water phantom and the leakage dose distribution around the applicator were calculated. Finally, MC data were validated experimentally for a 192Ir mHDR-v2 source by measuring (i) dose distributions with radiochromic EBT3 films (ISP); (ii) percentage depth-dose (PDD) curve with the parallel-plate ionization chamber Advanced Markus (PTW); and (iii) absolute dose rate with EBT3 films and the PinPoint T31016 (PTW) ionization chamber. Results: The new applicator is made of tungsten alloy (Densimet) and consists of a set of interchangeable collimators. Three catheters are used to allocate the source at prefixed dwell positions with preset weights to produce a homogenous dose distribution at the typical prescription depth of 3 mm in water. The same plan is used for all available collimators. PDD, absolute dose rate per unit of air kerma strength, and off-axis profiles in a cylindrical water phantom are reported. These data can be used for treatment planning. Leakage around the applicator was also scored. The dose distributions, PDD, and absolute dose rate calculated agree within experimental uncertainties with the doses measured: differences of MC data with chamber measurements are up to 0.8% and with radiochromic films are up to 3.5%. Conclusions: The new applicator and the dosimetric data provided here will be a valuable tool in clinical practice, making treatment of large skin lesions simpler, faster, and safer. Also the dose to surrounding healthy tissues is minimal.
SN  - 0094-2405
UR  - https://doi.org/10.1118/1.4943381
DO  - 10.1118/1.4943381
LA  - English
N1  - WOS:000373711000007
ID  - Candela-Juan_etal2016
ER  -