Tumour Dose Estimation using Automated TLD Techniques

Ferguson, Helen M.; Lambert, G.; Gustard, Deborah; Harrison, R. M.

doi:10.1080/028418698430449

Cited by 5 publications

(4 citation statements)

References 19 publications

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“…[ 22 ] Patients with pelvis had 91.3% (21/23) below recommended dose tolerance limit which is also in good agreement with Ferguson et al . [ 23 ] and Meijer et al . [ 24 ] values.…”

Section: Discussionmentioning

confidence: 99%

Verification of entrance dose measurements with thermoluminescent dosimeters in conventional radiotherapy procedures delivered with Co-60 teletherapy machine

Evwierhurhoma¹,

Ibitoye²,

Ojieh³

et al. 2015

Ann Med Health Sci Res

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Background:The use of in vivo dosimetry with thermolumiscent dosimeters (TLDs) as a veritable means of quality control in conventional radiotherapy procedures was determined in this work.Aim:The objective of this study was to determine the role of in vivo dosimetry with thermoluminescent dosimeters (TLDs) as part of quality control and audit in conventional radiotherapy procedures delivered with Co-60 teletherapy machine.Subjects and Methods:Fifty-seven patients with cancers of the breast, pelvis, head and neck were admitted for this study. TLD system at the Radiation Monitoring and Protection Centre, Lagos State University, Ojo, Lagos-Nigeria was used for the in vivo entrance dose readings. All patients were treated with Co-60 (T780c) teletherapy machine at 80 cm source to surface distance located at Eko Hospitals, Lagos. Two TLDs were placed on the patient surface within 1 cm from the center of the field of treatment. Build-up material made of paraffin wax with a density of 0.939 g/cm3 and a thickness 0.5 cm was placed on top of the TLDs. A RADOS RE 200 TLD reader was used to read out the TLDs over 12 s and at a temperature of 300°C.Results:The results showed that there was no significant difference between the expected dose and measured dose of breast (P = 0.11), H and N (P = 0.52), and pelvis (P = 0.31) patients. Furthermore, percentage difference between expected dose and measured dose of the three treatment sites were not significantly different (P = 0.11). More so, 88.9% (16/18) treated breast, 91.3% (21/23) pelvis, and 86.7% (13/15) H and N patients had percentage deviation difference less than 5%. In general, 89.3% (50/56) patients admitted for this study had their percentage deviation difference below 5% recommended standard limit.Conclusion:The values obtained establish that there are no major differences from similar studies reported in literature. This study was also part of quality control and audit of the radiotherapy procedures in the center as expected by national and international regulatory bodies.

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“…[ 22 ] Patients with pelvis had 91.3% (21/23) below recommended dose tolerance limit which is also in good agreement with Ferguson et al . [ 23 ] and Meijer et al . [ 24 ] values.…”

Section: Discussionmentioning

confidence: 99%

Verification of entrance dose measurements with thermoluminescent dosimeters in conventional radiotherapy procedures delivered with Co-60 teletherapy machine

Evwierhurhoma¹,

Ibitoye²,

Ojieh³

et al. 2015

Ann Med Health Sci Res

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“…Studies have been carried out with TLD's and diodes, giving typical mean discrepancies and standard deviations for different treatments 3,[5][6][7][8][9][10][11][12][13][14][15][16] .…”

Section: Introductionmentioning

confidence: 99%

Clinical results of entrance dose in vivo dosimetry for high energy photons in external beam radiotherapy using MOSFETs

Morton

Bhat

Williams³

et al. 2007

Australas. Phys. Eng. Sci. Med.

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Thomson and Nielsen TN-502 RD MOSFETs were used for entrance dose in vivo dosimetry for 6 and 10 MV photons. A total of 24 patients were tested, 10 breast, 8 prostate, 5 lung and 1 head and neck. For prostates three fields were checked. For all other plans all fields were checked. An action threshold of 8% was set for any one field and 5% for all fields combined. The total number of fields tested was 56, with a mean discrepancy of 1.4% and S.D. of 2.6%. Breasts had a mean discrepancy of 1.8% and S.D. of 2.8%. Prostates had a mean discrepancy of 1.3% and S.D. of 2.9%. For 3 fields combined, prostates had a mean of 1.3% and S.D. of 1.8%. These results are similar to results obtained with diodes and TLDs for the same techniques.

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“…[2–921] Although application of appropriate sets of calibration function and ECCs would increase the TLDs’ precision, one should see it in the context of acceptable range of variation for TL measurements, which is considered to be less than 10%. [122122] Radiotherapy has the potential for accidental exposures. As described in ICRP Report-86,[23] errors in device operation, source calibration, and treatment calculation may lead to serious accidents, which in most cases can be prevented by implementing adequate in vivo dosimetry.…”

Section: Resultsmentioning

confidence: 99%

“…In spite of intrinsic uncertainty, TLDs have been used widely for this purpose to find about weak points in treatment chain. [712152122]…”

Section: Resultsmentioning

confidence: 99%

Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy

Moghaddam¹,

Vahabi-Moghaddam²,

Sadremomtaz³

2013

J Med Phys

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In vivo dosimetry was carried out for 152 patients receiving external beam radiotherapy and the treatment sites were divided into two main groups: Thorax, Abdomen, and Pelvic (120 fields) and Head and Neck (52 fields). Combined entrance and exit dose measurements were performed using LiF: Mg, Cu, P thermoluminescent dosimeters (TLDs). Water-equivalent (effective) thicknesses and target dose were evaluated using dose transmission data. The ratio of measured to expected value for each quantity was considered as an indicator for the accuracy of the parameter. The average ratio of the entrance dose was evaluated as 1.01 ± 0.07. In the diameter measurement, the mean ratio of effective depth divided by the contour depth is 1.00 ± 0.13 that shows a wide distribution which reflects the influence of contour inaccuracies as well as tissue inhomogeneities. At the target level, the mean ratio of measured to the prescribed dose is 1.00 ± 0.07. According to our findings, the difference between effective depth and patient depth has a direct relation to target dose discrepancies. There are some inevitable sources which may cause the difference. Evaluation and application of effective diameter in treatment calculations would lead to a more reliable target dose, especially for fields which involve Thorax, Abdomen, and Pelvic.

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Tumour Dose Estimation using Automated TLD Techniques

Cited by 5 publications

References 19 publications

Verification of entrance dose measurements with thermoluminescent dosimeters in conventional radiotherapy procedures delivered with Co-60 teletherapy machine

Verification of entrance dose measurements with thermoluminescent dosimeters in conventional radiotherapy procedures delivered with Co-60 teletherapy machine

Clinical results of entrance dose in vivo dosimetry for high energy photons in external beam radiotherapy using MOSFETs

Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy

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