External audit of photon beams by mailed film dosimetry: feasibility study

Novotny, J.; Gomola, Igor; Iżewska, J.; Huyskens, D.; Dutreix, A.

doi:10.1088/0031-9155/42/7/004

Cited by 15 publications

(8 citation statements)

References 22 publications

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“…1͑a͒ and Table II show that there is a large variation in sensitometric curves between the Kodak films indicated by TAA, PAA, and AAA, which must be ascribed to differences in composition of the various batches of film originating from the three institutions. These differences are markedly larger than the values mentioned by some groups, 8,21 but in agreement with the strong dependence of shape of sensitivity curves on the production batch, as reported by others. 12,22 This difference in observation with II.…”

Section: A Batch Compositionsupporting

confidence: 91%

“…This somewhat smaller intra-versus interinstitutional batch variability might be fortuitous and due to the time and amount of film batches bought by a specific institution. The differences are, however, larger than the 1.6% ͑one standard deviation͒ mentioned by Novotny et al 21 The sensitometric curves of the CEA films were obtained from two batches, as indicated in Fig. 5, and demonstrate a large variation for both batches each over a period of about a year.…”

Section: Long-term Variation Of Sensitometric Curvesmentioning

confidence: 59%

“…OD difference at 50 cGy respect to the work of Novotny and co-workers 21 might, however, be related to their use of relative sensitometric curves rather than absolute OD values. There is a negligible difference between the sensitometric curves of the CEA films indicated by PAA and AAA.…”

Section: Effect Figure Comparisonmentioning

confidence: 80%

“…10 Furthermore, before a series of films was processed, two ''dummy'' films were processed in order to remove dust that may have accumulated on the transport system of the processor during idle time. Novotny et al 21 have shown that mailing of ͑Kodak͒ films does not alter the properties of these films and did not produce unwanted artifacts. Furthermore, if films would be irradiated during transport, its effect will be eliminated by fog correction, as described in a previous paragraph.…”

Section: Methodsmentioning

confidence: 99%

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Interinstitutional variations of sensitometric curves of radiographic dosimetric films

Bos¹,

Danciu²,

Cheng³

et al. 2002

Medical Physics

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Depth and field size dependence of the sensitometric curves of radiographic films have been studied by various groups. Limited information is, however, available on the magnitude of the variations in sensitometric curves applied in clinical practice in different institutions. In this study we assessed in a systematic way the effect of the various parameters influencing the shape of the sensitometric curve: batch composition, irradiation conditions, film processing, and film scanning. Two types of film, Kodak X-Omat V and CEA TVS, were irradiated, processed, and analyzed in three different institutions. The interinstitutional variation of the sensitometric curves, expressed as the OD variation at 50 cGy, can be up to 32% and is mainly caused by differences in film processing and to a lesser degree to differences in batch composition, film scanning, and irradiation conditions. For the Kodak films, the average OD difference at 50 cGy between the three institutions is 17% as a result of differences in batch composition and 25% due to differences in processing conditions. For the CEA films these data are 6% and 24%, respectively. The long-term variation of the sensitometric curves of KODAK films in one institution was smaller than the differences in batch composition between the three institutions. The sensitometric curves of CEA films showed in one institution a large variation with time; the shape gradually varied from sigmoidal to quasilinear. By using relative OD values rather than absolute OD values, variations in sensitometric curves of KODAK films can be reduced to 2%. Consequently, one sensitometric curve is sufficient to derive relative dose values. If processing conditions are well controlled, it might therefore be advantageous to determine the absolute OD only at one or two dose values, in combination with a "universal" relative sensitometric curve.

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Section: A Batch Compositionsupporting

confidence: 91%

Section: Long-term Variation Of Sensitometric Curvesmentioning

confidence: 59%

Section: Effect Figure Comparisonmentioning

confidence: 80%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Interinstitutional variations of sensitometric curves of radiographic dosimetric films

Bos¹,

Danciu²,

Cheng³

et al. 2002

Medical Physics

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“…Novotny et al 15 have shown that a decrease in optical density of about 3% ͑for a dose of 0.45 Gy͒ and 1.8% ͑for a dose of 1.5 Gy͒ was observed per month of delay between film irradiation and film processing. It was therefore assumed that the errors in our procedure induced by time fading were less than 1%.…”

Section: E Processing Conditions and Measuring Instrumentsmentioning

confidence: 99%

Variation of sensitometric curves of radiographic films in high energy photon beams

et al. 2001

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Film dosimetry is an important tool for the verification of irradiation techniques. The shape of the sensitometric curve depends on the type of film as well as on the irradiation and processing conditions. Existing data concerning the influence of irradiation geometry on the sensitometric curve are conflicting. In particular the variation of optical density, OD, with field size and depth in a phantom shows large differences in magnitude between various authors. This variation, as well as the effect of beam energy and film plane orientation on OD, was therefore investigated for two types of film, Kodak X-Omat V and Agfa Structurix D2. Films were positioned in a solid phantom, either perpendicular or (almost) parallel to the beam axis, and irradiated to different dose levels using various photon beams (Co-60, 6 MV, 15 MV, 18 MV, 45 MV). It was found that the sensitometric curves of the Kodak film derived at different depths are almost identical for the four x-ray beams. For the Kodak film the differences in OD with depth are less than 2%, except for the Co-60 beam, where the difference is about 4% at 10 cm depth for a 15 cm x 15 cm field. The slope of the sensitometric curve of the Agfa film is somewhat more dependent on photon beam energy, depth and field size. The sensitometric curves of both types of film are almost independent of the film plane orientation, except for shallow depths. For Co-60 and for the same dose, the Kodak and Agfa films gave at dose maximum an OD lower by 4% and 6%, respectively, for the parallel compared to the perpendicular geometry. Good dosimetric results can be obtained if films from the same batch are irradiated with small to moderate field sizes (up to about 15 cm x 15 cm), at moderate depths (up to about 15 cm), using a single calibration curve, e.g., for a 10 cm x 10 cm field.

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An inter-centre quality assurance network for IMRT verification: Results of the ESTRO QUASIMODO project

Gillis

Wagter

Bohsung

et al. 2005

Radiotherapy and Oncology

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External audit of photon beams by mailed film dosimetry: feasibility study

Cited by 15 publications

References 22 publications

Interinstitutional variations of sensitometric curves of radiographic dosimetric films

Interinstitutional variations of sensitometric curves of radiographic dosimetric films

Variation of sensitometric curves of radiographic films in high energy photon beams

An inter-centre quality assurance network for IMRT verification: Results of the ESTRO QUASIMODO project

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