Mixed radiation dosimetry with LiF (TLD-100)

Busuoli, G.; Cavallini, A.; Fassó, A.; Rimondi, O.

doi:10.1088/0031-9155/15/4/007

Cited by 24 publications

(7 citation statements)

References 7 publications

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“…In photon radiotherapy with energies higher than 10 MV, and proton radiotherapy, the secondary dose to the patient from neutrons produced by photon interactions with high Z materials is of concern because of their higher relative biological effectiveness. By using the two-peak analysis in the LiF TLD glow curve developed in radiation protection, [135][136][137] the high (neutron) and low (photon and proton) LET dose components can be determined. These dose measurements may provide useful biological information.…”

Section: Future Needs and Evolving Technology For Ivdmentioning

confidence: 99%

In vivo dosimetry in external beam radiotherapy

et al. 2013

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In vivo dosimetry (IVD) is in use in external beam radiotherapy (EBRT) to detect major errors, to assess clinically relevant differences between planned and delivered dose, to record dose received by individual patients, and to fulfill legal requirements. After discussing briefly the main characteristics of the most commonly applied IVD systems, the clinical experience of IVD during EBRT will be summarized. Advancement of the traditional aspects of in vivo dosimetry as well as the development of currently available and newly emerging noninterventional technologies are required for large-scale implementation of IVD in EBRT. These new technologies include the development of electronic portal imaging devices for 2D and 3D patient dosimetry during advanced treatment techniques, such as IMRT and VMAT, and the use of IVD in proton and ion radiotherapy by measuring the decay of radiation-induced radionuclides. In the final analysis, we will show in this Vision 20∕20 paper that in addition to regulatory compliance and reimbursement issues, the rationale for in vivo measurements is to provide an accurate and independent verification of the overall treatment procedure. It will enable the identification of potential errors in dose calculation, data transfer, dose delivery, patient setup, and changes in patient anatomy. It is the authors' opinion that all treatments with curative intent should be verified through in vivo dose measurements in combination with pretreatment checks.

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Section: Future Needs and Evolving Technology For Ivdmentioning

confidence: 99%

In vivo dosimetry in external beam radiotherapy

et al. 2013

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“…Any TLD measurements at high X‐ray energies will therefore include a response to the neutron fluence generated by the accelerator. Although the neutron dose can be resolved from a TLD‐100 signal, the procedure is not simple, and the resulting measurements have high uncertainty (4) . It is desirable for a TLD to be able to measure solely the photon component of the dose.…”

Section: Introductionmentioning

confidence: 99%

The use of LiF (TLD‐100) as an out‐of‐field dosimeter

Kry

Price

Followill

et al. 2007

J Applied Clin Med Phys

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The commonly used thermoluminescent dosimeter TLD‐100 (Harshaw Chemical Company, Solon, OH) responds not only to photons and electrons, but also to neutrons that are produced during high‐energy therapies. As a result, TLD‐100 measurements outside of the treatment field are suspect when high‐energy radiation is used. Although alternatives such as TLD‐700 do not respond to neutrons, specialty dosimeters of this kind are expensive and are not routinely used in most clinics. In the current study, we examined the accuracy of TLD‐100 in measuring the out‐of‐field photon dose as a function of treatment energy.To determine the accuracy of TLD‐100 as compared with TLD‐700, TLD‐100 was irradiated outside of the treatment field by medical accelerators operated at 6, 10, 15, and 18 MV. In an effort to eliminate the response of TLD‐100 to neutrons, TLD capsules were encased in varying thicknesses of cadmium foil (0.25 – 0.75 mm) before being irradiated at 18 MV. The out‐of‐field TLD‐100 was found to be accurate at 6 MV and 10 MV, but to be substantially over‐responsive at 15 MV and 18 MV (by up to 1063% relative to TLD‐700). By wrapping the TLD‐100 in up to 0.75 mm of cadmium, it was possible to drastically reduce (down to 39% on average) the over‐response of the TLD‐100; however, total removal of the over‐responsiveness was not possible. Although TLD‐100 is well suited for measuring out‐of‐field dose at energies as high as 10 MV, at higher energies (15 MV or greater), this dosimeter over‐responds substantially and should not be used. Although encasing the TLD in cadmium minimized over‐response to a degree, the reduction was not sufficient to make TLD‐100 viable for measuring out‐of‐field dose at high treatment energies.PACS numbers: 87.52.‐g, 87.53.‐j, 87.53.‐Dq

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“…(nêutron e fótons) também é bem documentado [Busuoli et al, 1970;Nash e Johnson, 1977;Budd et al, 1979;Youssian et al, 1998e Kry et al, 2007. O TLD-100 e, principalmente, a variação TLD-600 apresentam alta sensibilidade a nêutrons enquanto o TLD-700, por possuir grande enriquecimento do isótopo 7 do lítio, cuja seção de choque é muito pequena para interações com esse tipo de radiação, é praticamente insensível.…”

Section: Tratamento Térmicounclassified

“…Na análise das curvas de emissão apresentada na seção 4.7.1, a única alteração de curva de emissão encontrada (e que já era esperada e documentada na literatura [Busuoli et al, 1970e Youssian, 1998 Resultados da irradiação com feixe misto proveniente da fonte de .................................................................................. 22 Figura 3-2: Curva de emissão do CaF 2 obtida 24 horas após irradiação com 60 Co e dose de 10 mGy. A leitura foi feita com aquecimento de 5 °C/s até 380 °C.…”

Section: Influência Da Contaminação Por Nêutrons Na Resposta Tlunclassified

Avaliação de dosímetros termoluminescentes para uso em radioterapia com fótons de alta energia

Batista¹

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Aos meus pais e irmãos, que mesmo sem saber o que eu fazia me apoiavam. À Lu, pelo companheirismo, incentivo e diversas ajudas ao longo desse trabalho. Ao Fábio Júnior, que várias vezes trabalhou no meu lugar para que eu pudesse fazer essa dissertação, pelos incentivos, discussões e ajudas que sempre ofereceu. Ao Leandro e André, físicos médicos que não se importam de gastar o tempo "produzindo ciência", pela ajuda nas irradiações com o Cobalto e pelas sugestões. Ao físico Anselmo, pela disponibilidade em ajudar nas medidas. Ao Marcos, que transformou em realidade as ponteiras que a gente imaginou. À Nancy e Chico, por tomarem conta do laboratório e por ajudar a resolver os problemas que eu encontrava. Às professoras Emico e Ana Regina, pelos sorrisos, conversas e incentivos. À professora Nora, pela disposição em ajudar sempre que necessário. Ao Marcelo e a Cris por dividirem o lar comigo na fase inicial desse trabalho e ao Daniel e Paula pela hospedagem durante a fase final. Aos amigos Marcelo, Helvécio, Renan e Flávio por servirem de exemplo e por dividirem as suas experiências acadêmicas comigo. Aos serviços de radioterapia que permitiram a realização das medidas.

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Mixed radiation dosimetry with LiF (TLD-100)

Cited by 24 publications

References 7 publications

In vivo dosimetry in external beam radiotherapy

In vivo dosimetry in external beam radiotherapy

The use of LiF (TLD‐100) as an out‐of‐field dosimeter

Avaliação de dosímetros termoluminescentes para uso em radioterapia com fótons de alta energia

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