Use of parallel‐plate ionization chambers in reference dosimetry of NOVAC and LIAC^® mobile electron linear accelerators for intraoperative radiotherapy: a multi‐center survey

Abstract

The present study confirms that parallel-plate ionization chambers can properly and accurately substitute ferrous sulphate detectors in reference dosimetry of LIAC and NOVAC mobile linear accelerators. Therefore, we hope that the most commonly used protocols for reference dosimetry in external-beam radiotherapy will be updated in order to provide guidance in the calibration of electron beams from linear accelerators dedicated to IORT, so that users may benefit from specific, authoritative and up-to-date recommendations.

Electron radiotherapy (IOERT) for applications outside of the breast: Dosimetry and influence of tissue inhomogeneities

“…The reproducibility of the entire measurement setup was found to be ± 1.7, 1.4, 1.4% (2 standard deviations) for 6,9,12 MeV respectively and was considered acceptable. The measurements of applicator factors for all collimators with diode are summarized in Table 4 and the comparison of applicator factors measured with diode, films and TLDs is shown in Fig.…”

“…The Mobetron has the advantage of the dose per pulse around 0.55 cGy, similar to that of a standard LINAC, whereas other machines dedicated for IOERT have a higher dose per pulse, up to 70 cGy [12]. As such, the Mobetron 2000 can be commissioned using standard dosimetry protocols [20,37] such as the AAPM TG-51.…”

“…Machines dedicated for IOERT include the NOVAC 11 and Liac (Sordina, Aprilia, Italy) mobile, [3][4][5][6][7][8][9][10][11][12] MeV electron beams linear accelerators mounted on a robotic arm. They use a hard-docking technique, where a PMMA applicator is rigidly fixed to the linac, and have instantaneous dose rate up to 20 Gy/min and dose per pulse up to 70 mGy which result in substantial dosimetric problems [11,12].…”

Evaluating the performance characteristics of some ion chamber dosimeters in high dose per pulse intraoperative electron beam radiation therapy

“…These machines are mobile and compact ones which can deliver the required radiation dose in a standard operating room [7]. These accelerators can produce the electron beam from 3 MeV to 12 MeV energy with high dose per pulse values up to 70 mGy/pulse [8].…”

Dosimetria gel polimérica usando imagem de ressonância magnética para aplicação em radioterapia

“…A dosimetria nesses aparelhos é muito importante, pois em qualquer tratamento é necessário que a dose planejada seja igual à dose que será entregue ao paciente (ABAZA, 2016). Os dosímetros que são normalmente utilizados em radioterapia são os dosímetros termoluminescentes (TLDs), câmaras de ionização e filmes radiocrômicos (ALQATHAMI et al, 2016;PAUKSTYTE, S.;URBONAVICIUS, 2017;SCALCHI et al, 2017;ALDELAIJA et al, 2018;HAURI, SCHNEIDER, 2018;O'BRIEN et al, 2018;SINGH et al, 2018). Com o uso dos dois primeiros dosímetros é possível obter informações dosimétricas ponto a ponto, enquanto com o uso dos filmes radiocrômicos é possível obter uma informação bidimensional de dose.…”