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Showing 5 results for Skin Dose
B.aghahadi, Z. Zhang, S. Zareh, S. Sarkar, P.s.tayebi,
Volume 3, Issue 4 (3-2006)
Abstract
ABSTRACT Background: The X-ray machines used for radiodiagnosis should meet certain quality assurance (QA) programmes . These are necessary to have good quality radiographs at reasonably low exposure to patients. Materials and Methods: Dose reduction methods in abdomen X-ray examination were carried out in 10 hospitals in Tehran. This paper presents the work, which was implemented on 200 patients and evaluated using the entrance skin dose (ESD) in the Anterior-Posterior (AP) abdomen projection measured directly at the center of the X-ray field. In addition, the machine room, and dark room parameters, as well as work practices and repeat rates were studied . Results: The quality control (QC) parameters and the ESD were evaluated utilizing an anthropologic phantom to define the optimal exposure condition at all hospitals before and after QC. Results show that after using the QC parameters and optimization of the exposure condition s , the mean of mAs and ESD can be decrease d by 62% and 65% respectively. Conclusion: The quality of the radiograph s generally increased. The reported method is easily implemented in any clinical situation where optimization of abdomen radiography is necessary.
Dr. M.b. Tavakoli, S. Monsef, M. Hashemi, H. Emami,
Volume 8, Issue 3 (12-2010)
Abstract
Background: Practice of interventional cardiology
procedures such as Coronary angiography (CA) and
percutaneous transluminal coronary angioplasty
(PTCA) has largely increased in recent years and is
now changing to a matter of routine in many
hospitals. The purpose of this study was to measure
skin and organ doses in patients undergoing CA and
PTCA and to find a probable relation with cardiologist's
work experience. Materials and Methods: A
group of 57 patients who were admitted to Nour and
Chamran hospitals, Isfahan, Iran, either for CA (n=37)
or PTCA (n=20) was checked for skin, eyes and
thyroid gland radiation dose. Skin dose measurement
was carried out with thermoluminescent dosimeters
(TLD-100) placed at three different positions on the
patients' bodies. Also the thyroid and eye doses were
measured using the same procedure. Results: Mean
median, standard deviation and maximum doses for
these results are presented. Maximum values found
for skin in CA, PTCA, thyroid gland and eyes were
41.00, 73.90, 3.10 and 1.43 cGy, respectively.
Average exposure time for CA and PTCA was 4.2±2.6
and 10.8±8.2 minutes, respectively. Radiation dose
to the critical areas in each procedure in addition to
its relation to the type of procedure was studied.
Correlation between maximum skin dose and
cardiologists' work experience was also investigated.
Conclusion: 85% of the cases in CA and 78% of cases
in PTCA received maximum skin dose of lower than
25cGy well below the threshold of 2 Gy suggestions
for transient erythema. Iran. J. Radiat. Res., 2010
8 (3): 155-160
F. Arianfard, Dr. M.a. Mosleh-Shirazi, S. Karbasi, S. Mousavi,
Volume 16, Issue 3 (7-2018)
Abstract
Background: To study attenuation and increased skin dose for the iBEAM Standard couchtop, and attenuation of the BreastSTEP board, for an Elekta Compact 6 MV accelerator. Materials and Methods: Couchtop attenuation were measured for the range of gantry angles 125°-180° and field sizes 5×5-20×8 cm2. H&N extension and the BreastSTEP attenuations measured in an 8×8 cm2 field. The couchtop effect on percentage depth-dose (PDD) measured by an EFD diode for field sizes 5×5-20×20 cm2 and compared with that produced by a Co-60 beam passing through a ‘tennis-racket’ couch insert. A Monte Carlo (MC) model of the couchtop produced to provide more superficial PDDs. (PDDs that are more superficial) Results: Maximum couchtop attenuation (7.6%) measured for the 135° gantry and 5×5 cm2 field. Couch extension attenuation was 1.5% lower. Adding BreastSTEP increased attenuation by 2.4%. MC attenuation results agreed with measurements to within 0.2%. The couchtop removed the dose buildup effect almost completely and increased the PDD at 0.4 mm depth by 60.6%-74.6%. MC-calculated PDDs at the depth range of skin basal cell layer (0.1-0.4 mm) increased by 55.3%-63.2%. The couch insert in the Co-60 beam increased the dose at 0.4 mm depth by 18.1%. For the same dose prescription at 10 cm depth, the insert in the Co-60 beam produced a skin dose 49.7% lower than the couchtop at 6 MV. Conclusion: These results provide useful practical data on attenuation and skin dose increase applicable to many centres. The accelerator-couchtop combination creates a greater skin dose increase than a tennis-racket insert on a Co-60 unit.
M.t. Bahreyni Toossi, Ph.d., H. Zare, S. Bayani, M. Hashemi, N. Mohamadian, Z. Eslami, S. Seyedi,
Volume 18, Issue 2 (4-2020)
Abstract
Background: Endoscopic retrograde cholangiopancreatography (ERCP) is now widely used in the diagnosis and treatment of gastrointestinal tract disorders. A large number of X-ray fluoroscopy and digital radiographs make ERCP as an interventional radiological procedure. In this study, patients' and examiner's entrance skin doses (ESDs) were measured during diagnosis and treatment procedures and patients' effective dose (ED) were calculated. Materials and Methods: Thermoluminescent dosimeters (TLDs) and dose area product meter (DAP) were used to measure ESDs of 30 patients and examiner and calculate patients' ED. Besides, to assess the effectiveness of an extra lead shield in decreasing examiner's ESDs, a lead cover was wrapped around the X-ray tube. The data were analyzed with IBM SPSS Statistics version 16 software. Results: The mean DAP and fluoroscopy time (FT) of the diagnostic procedure were 4.09 Gy.cm2 and 32.4 s while those of the therapeutic procedure were 7.60 Gy.cm2 and 76.2 s. The strong linear correlation between DAP and FT was observed for the therapeutic procedures but the diagnostic ones. The patients' mean EDs of diagnostic procedure (1.21±0.52 mSv) and therapeutic one (2.25±1.72 mSv) were calculated. Moreover, the shielding cover around the X-ray tube decreased ESDs of the organs of interest except gonads. Conclusions: The results reveal that therapeutic ERCP procedure imposes a greater radiation dose compared to diagnostic ERCP one. However, the doses of the patient and the examiner depend highly on examiner's experience, technical skills and knowledge in radiation protection. The results suggest that attempts to reduce radiation doses should be made.
P. Saadatmand, Ph.d., S.r. Mahdavi, A. Nikoofar, G. Esmaili, M. Jalilifar, S. Khazaie, S. Vejdani,
Volume 23, Issue 1 (1-2025)
Abstract
Background: Estimating the accuracy of Treatment Planning Systems (TPS) in skin dose calculation is essential to achieving the intended therapeutic outcomes in breast cancer radiotherapy. This study aims to validate tomotherapy TPS accuracy in skin dose estimation. Materials and Methods: The ability of Accuray Precision TPS to provide precise skin dose calculations was examined by utilizing the Gafchromic EBT3 film, which was placed on the surface of the cylinder Delta4 phantom. The target volume received a 2Gy dose following setup validation. The accuracy of TPS was assessed using distinct spatial resolutions for dose calculation in helical and direct Tomotherapy plans. Using the RIT software, gamma analysis was employed to evaluate the precision of TPS skin dose distribution relative to the EBT3 film. Results: Comparison of skin dose distribution between the TPS and EBT3 films demonstrated acceptable gamma passing rates for helical (up to 98.51%) and direct plan (up to 90.41%) using gamma index criteria of 5 mm/5%. However, the gamma index of helical and direct tomotherapy plans with passing criteria of 3 mm/3% was 84.15% and 79.12%, respectively. Our findings indicate satisfactory consistency (3-5%) between measured and calculated skin doses using the EBT3 film and TPS, employing "high" spatial resolution dose calculation in helical and direct Tomotherapy plans. Conclusion: The reliability of the tomotherapy TPS in skin dose calculation is maintained by utilizing high spatial resolution for dose computation. The accuracy of TPS validated against the Gafchoromic EBT3 film was within an acceptable gamma-passing rate.
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