Correlation between temperature and dose rate dependence of semiconductor response; influence of accumulated dose

Dam, J. Van; Leunens, G.; Dutreix, A.

doi:10.1016/0167-8140(90)90035-u

Cited by 54 publications

(43 citation statements)

References 6 publications

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“…The ion chamber was placed at maximum depth in the plastic water phantom and the diodes at surface. Diode sensitivity increases with temperature 10,15 and the use of correction factors to account for this effect is recommended. The temperature correction factor is defined as:…”

Section: Diode Calibrationmentioning

confidence: 99%

Implementation of in vivo Dosimetry with Isorad™ Semiconductor Diodes in Radiotherapy Treatments of the Pelvis

Rodríguez¹,

Abrego²,

Pineda³

2008

Medical Dosimetry

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Section: Diode Calibrationmentioning

confidence: 99%

Implementation of in vivo Dosimetry with Isorad™ Semiconductor Diodes in Radiotherapy Treatments of the Pelvis

Rodríguez¹,

Abrego²,

Pineda³

2008

Medical Dosimetry

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“…This effect depends on accumulated dose, especially from high-energy photon beams containing neutron contamination. 3,4 Dose rate dependence has previously been reported to be a problem for n-type Si detectors, 1 but not for preirradiated p-type detectors. 5,6 Diodes for radiation detection are normally supplied by the manufacturer preirradiated, to minimize variations in sensitivity and dose rate dependence with further accumulated dose.…”

mentioning

confidence: 98%

The effect of dose rate dependence ofp-type silicon detectors on linac relative dosimetry

Wilkins

Cygler

et al. 1997

Med. Phys.

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Cumulative radiation damage to silicon semiconductor diode detectors can induce dose rate dependent sensitivity, a concern in the pulsed beam of a linac. Two p-Si diode photon detectors were used in this study, diodes A and B. Both were preirradiated by the supplier to 5 kGy, with diode A receiving an estimated 8 kGy from measurements, and diode B, 25 kGy. At 6 MV, the PDD measured with diode B was lower (by 4.4% at a depth of 25 cm) than diode A. Using SSD to vary the dose per pulse from 0.02 to 0.64 mGy/pulse, diode A was dose rate independent (within 2%), while the sensitivity of diode B changed by 13%. Silicon diode detectors should be checked regularly against ionization chambers in the pulsed beam of a linac, especially older high-resistivity diodes that have accumulated dose from high-energy photon beams.

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“…, 20 , 21 Grusell and Rikner found increased sensitivity for p ‐type detectors with increasing temperature, especially after an accumulated dose 20 . Van Dam, Leunens, and Detreix later confirmed this temperature effect, but decided clinically not to correct for the temperature effect, except for long irradiation such as TBI at low dose rate 21 . They argued that the time between taping of the detector and start of the patient irradiation was very short (about 10 s) and that the treatment times were on the order of 1 min.…”

Section: Discussionmentioning

confidence: 99%

“…They suggested that further investigation of the temperature properties of all diodes was required to explain the three different temperature responses. Based on these studies, 6 , 20 , 21 we have not included the temperature effect for typical clinical situations in our program.…”

Section: Discussionmentioning

confidence: 99%

Entrance dose measurements for in‐vivo diode dosimetry: Comparison of correction factors for two types of commercial silicon diode detectors

Zhu

2000

J Applied Clin Med Phys

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Silicon diode dosimeters have been used routinely for in‐vivo dosimetry. Despite their popularity, an appropriate implementation of an in‐vivo dosimetry program using diode detectors remains a challenge for clinical physicists. One common approach is to relate the diode readout to the entrance dose, that is, dose to the reference depth of maximum dose such as dmax for the 10×10 cm2 field. Various correction factors are needed in order to properly infer the entrance dose from the diode readout, depending on field sizes, target‐to‐surface distances (TSD), and accessories (such as wedges and compensate filters). In some clinical practices, however, no correction factor is used. In this case, a diode‐dosimeter‐based in‐vivo dosimetry program may not serve the purpose effectively; that is, to provide an overall check of the dosimetry procedure. In this paper, we provide a formula to relate the diode readout to the entrance dose. Correction factors for TSD, field size, and wedges used in this formula are also clearly defined. Two types of commercial diode detectors, ISORAD (n‐type) and the newly available QED (p‐type) (Sun Nuclear Corporation), are studied. We compared correction factors for TSDs, field sizes, and wedges. Our results are consistent with the theory of radiation damage of silicon diodes. Radiation damage has been shown to be more serious for n‐type than for p‐type detectors. In general, both types of diode dosimeters require correction factors depending on beam energy, TSD, field size, and wedge. The magnitudes of corrections for QED (p‐type) diodes are smaller than ISORAD detectors.PACS number(s): 87.66.–a, 87.52.–g

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Correlation between temperature and dose rate dependence of semiconductor response; influence of accumulated dose

Cited by 54 publications

References 6 publications

Implementation of in vivo Dosimetry with Isorad™ Semiconductor Diodes in Radiotherapy Treatments of the Pelvis

Implementation of in vivo Dosimetry with Isorad™ Semiconductor Diodes in Radiotherapy Treatments of the Pelvis

The effect of dose rate dependence ofp-type silicon detectors on linac relative dosimetry

Entrance dose measurements for in‐vivo diode dosimetry: Comparison of correction factors for two types of commercial silicon diode detectors

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