Displaying publications 1 - 20 of 79 in total

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  1. Wahabi JM, Ung NM, Mahdiraji GA, Wong JHD
    Radiat Prot Dosimetry, 2024 Mar 02;200(3):264-273.
    PMID: 38123475 DOI: 10.1093/rpd/ncad303
    The radioluminescent (RL) dosemeter is excellent for real-time radiation measurement and can be used in various applications. A plastic scintillator is often the choice sensor because of its size and tissue equivalency. This study aims to characterise a novel plastic scintillator irradiated with high-energy photon beams. An RL dosimetry system was developed using the plastic scintillator. The RL dosimetry system was irradiated using a linear accelerator to characterise the dose linearity, dose rate, energy dependency and depth dose. The developed system showed a linear response toward the dose and dose rate. An energy dependency factor of 1.06 was observed. Depth dose measurement showed a mean deviation of 1.21% from the treatment planning system. The response and characteristics of the plastic scintillator show that it may be used as an alternative in an RL dosimetry system.
    Matched MeSH terms: Radiometry*
  2. Abdul Hadi MFR, Abdullah AN, Hashikin NAA, Ying CK, Yeong CH, Yoon TL, et al.
    Med Phys, 2022 Dec;49(12):7742-7753.
    PMID: 36098271 DOI: 10.1002/mp.15980
    PURPOSE: Monte Carlo (MC) simulation is an important technique that can help design advanced and challenging experimental setups. GATE (Geant4 application for tomographic emission) is a useful simulation toolkit for applications in nuclear medicine. Transarterial radioembolization is a treatment for liver cancer, where microspheres embedded with yttrium-90 (90 Y) are administered intra-arterially to the tumor. Personalized dosimetry for this treatment may provide higher dosimetry accuracy compared to the conventional partition model (PM) calculation. However, incorporation of three-dimensional tomographic input data into MC simulation is an intricate process. In this article, 3D Slicer, free and open-source software, was utilized for the incorporation of patient tomographic images into GATE to demonstrate the feasibility of personalized dosimetry in hepatic radioembolization with 90 Y.

    METHODS: In this article, the steps involved in importing, segmenting, and registering tomographic images using 3D Slicer were thoroughly described, before importing them into GATE for MC simulation. The absorbed doses estimated using GATE were then compared with that of PM. SlicerRT, a 3D Slicer extension, was then used to visualize the isodose from the MC simulation.

    RESULTS: A workflow diagram consisting of all the steps taken in the utilization of 3D Slicer for personalized dosimetry in 90 Y radioembolization has been presented in this article. In comparison to the MC simulation, the absorbed doses to the tumor and normal liver were overestimated by PM by 105.55% and 20.23%, respectively, whereas for lungs, the absorbed dose estimated by PM was underestimated by 25.32%. These values were supported by the isodose distribution obtained via SlicerRT, suggesting the presence of beta particles outside the volumes of interest. These findings demonstrate the importance of personalized dosimetry for a more accurate absorbed dose estimation compared to PM.

    CONCLUSION: The methodology provided in this study can assist users (especially students or researchers who are new to MC simulation) in navigating intricate steps required in the importation of tomographic data for MC simulation. These steps can also be utilized for other radiation therapy related applications, not necessarily limited to internal dosimetry.

    Matched MeSH terms: Radiometry/methods
  3. Bradley DA, Chong CS
    Int J Rad Appl Instrum A, 1991;42(8):767-70.
    PMID: 1666633
    New, detailed measurements have been made of the photon spectrum of the radionuclide 241Am. Observations, recorded for a 95% confidence level over local background, provide affirmation of a number of lines previously considered to be of equivocal existence. A number of hitherto unreported emissions are similarly observed. Peak areas, expressed as a percentage of that for the 59.54 keV emission, have been ascribed to all lines of the detailed spectrum. This leads to an estimated increase in the value of exposure calculated from the measured fluence spectrum, relative to that from the 59.54 keV line, of (3.1 +/- 0.8)%, taking into account all emissions beyond the predominating 59.54 keV gamma-ray emission.
    Matched MeSH terms: Radiometry
  4. Ismail Sulaiman, Khairuddin Mohamad Kontol, Faizal Azrin Abdul Razalim, Azman Jaafar
    MyJurnal
    The objective of this study was to measure indoor radon concentrations in the expected high risk area around Ipoh in Kinta Valley, Perak. The area was chosen based on its own special characteristics. The measurements were carried out by means of long term exposure (3 months) using CR-39 solid state nuclear track detector. The mean indoor radon concentration in Ipoh was 45 Bq/m3 which is equivalent to effective dose of 1.1 mSv/y. This value was higher compared to low or normal area in Bangi, Selangor but comparable to the world average value reported by UNSCEAR. The maximum value of indoor radon concentration measured was 87 Bq/m3.
    Matched MeSH terms: Radiometry
  5. Lee KH, Kandaiya S
    Appl Radiat Isot, 1996 Mar;47(3):361-3.
    PMID: 8935969
    Matched MeSH terms: Radiometry/instrumentation*; Radiometry/methods*
  6. Banjade DP, Tajuddin AA, Shukri A
    Appl Radiat Isot, 2001 Sep;55(3):297-302.
    PMID: 11515650
    Previous scattering and depth-dose investigations involving use of the Malaysian hardwood Rhizophora spp have shown this medium to produce good agreement with measurements made in water. Present study extends the comparison, now including measurements of percentage depth-dose made for photons at 6MV and 5 and 12MeV electron beams. For the 6 MV photon and 5 MeV electron beams, discrepancies between percentage depth-dose for Rhizophora spp and water, at all depths, are found to be within 2.6 and 2.4% respectively. At 12 MeV electron energies, measured percentage depth-doses in Rhizophora spp beyond 3.5cm depth are found to be in significant discord with those for water. The absorbed dose in water measured in Rhizophora spp at d(max) for all three beams produces discrepancies of no more than 1.1% when compared with measurements made in water.
    Matched MeSH terms: Radiometry/methods*
  7. Wahib NB, Abdul Sani SF, Ramli A, Ismail SS, Abdul Jabar MH, Khandaker MU, et al.
    Radiat Environ Biophys, 2020 08;59(3):523-537.
    PMID: 32462382 DOI: 10.1007/s00411-020-00846-x
    Accidents resulting in widespread dispersal of radioactive materials have given rise to a need for materials that are convenient in allowing individual dose assessment. The present study examines natural Dead Sea salt adopted as a model thermoluminescence dosimetry system. Samples were prepared in two different forms, loose-raw and loose-ground, subsequently exposed to 60Co gamma-rays, delivering doses in the range 2-10 Gy. Key thermoluminescence (TL) properties were examined, including glow curves, dose response, sensitivity, reproducibility and fading. Glow curves shapes were found to be independent of given dose, prominent TL peaks for the raw and ground samples appearing in the temperature ranges 361-385 ºC and 366-401 ºC, respectively. The deconvolution of glow curves has been undertaken using GlowFit, resulting in ten overlapping first-order kinetic glow peaks. For both sample forms, the integrated TL yield displays linearity of response with dose, the loose-raw salt showing some 2.5 × the sensitivity of the ground salt. The samples showed similar degrees of fading, with respective residual signals 28 days post-irradiation of 66% and 62% for the ground and raw forms respectively; conversely, confronted by light-induced fading the respective signal losses were 62% and 80%. The effective atomic number of the Dead Sea salt of 16.3 is comparable to that of TLD-200 (Zeff 16.3), suitable as an environmental radiation monitor in accident situations but requiring careful calibration in the reconstruction of soft tissue dose (soft tissue Zeff 7.2). Sample luminescence studies were carried out via Raman and Photoluminescence spectroscopy as well as X-ray diffraction, ionizing radiation dependent variation in lattice structure being found to influence TL response.
    Matched MeSH terms: Radiometry/methods*
  8. Wahib NB, Khandaker MU, Aqilah Binti Mohamad Ramli N, Sani SFA, Bradley DA
    Appl Radiat Isot, 2019 Jun;148:218-224.
    PMID: 31003071 DOI: 10.1016/j.apradiso.2019.04.001
    Study has been made of the thermoluminescence (TL) yield of various glass-based commercial kitchenware (Reko-China, Skoja-France, Godis-China, Glass Tum-Malaysia, Lodrat-France). Interest focuses on their potential for retrospective dosimetry. Use was made of a60Co gamma-ray irradiator, delivering doses in the range 2-10 Gy. Results for the various media show all the glassware brands to yield linearity of response against dose, with a lower limit of detection of ∼0.06 and ∼0.08 Gy for loose and compact powdered samples. Among all of the brands under study, the Lodrat glassware provides the greatest sensitivity, at 6.0 E+02 nC g-1 Gy-1 and 1.5E+03 nC g-1 Gy-1 for compact- and loose-powdered forms respectively. This is sufficiently sensitive to allow its use as a TL material for accident dosimetry (2 Gy being the threshold dose for the onset of a number of deterministic biological effects, including skin erythema and sterility). Energy Dispersive X-ray (EDX) analyses have been conducted, showing the presence of a number of impurities (including C, O, Na, Mg, Al, Si, Ca and Br). Fading of the irradiated glasses show the amount of better than 3% and 5% of the stored energy for both loose and compact powdered samples within 9 days post irradiation. As such, commercial kitchenware glass has the potential to act as relatively good TL material for gamma radiation dosimetry at accident levels. This is the first endeavour reporting the TL properties of low cost commercial kitchenware glasses for gamma-ray doses in the few Gy range, literature existing for doses from 8 Gy to 200 Gy.
    Matched MeSH terms: Radiometry/methods*
  9. Hashim AK, Hatif AR, Ahmed NM, Wadi IA, Al Qaaod AA
    Appl Radiat Isot, 2021 Jan;167:109410.
    PMID: 33065401 DOI: 10.1016/j.apradiso.2020.109410
    Radon and progeny concentration measurements in various drink samples are intrinsically important for assessing the health risks resulting from daily consumption of these drinks. In this study the comparison between two Solid State Nuclear Track Detectors (SSNTDs), the CR-39 and the CN-85 has been conducted for the purpose of evaluating the radon concentration, annual effective dose, the rate of exhalation of radon and the effective radium content in thirty-two different samples of soft drink, water, and milk available in the local Iraq markets. The results showed that there are significant differences in the measurement results for the two detectors. The annual effective dose of the investigated samples is still below the limit of International Commission on Radiological Protection (ICRP) recommendation in the measurements of both detectors.
    Matched MeSH terms: Radiometry/methods
  10. Samson DO, Aziz MZA, Shukri A, Mat Jafri MZ, Hashim R, Zuber SH, et al.
    Health Phys, 2023 Aug 01;125(2):77-91.
    PMID: 36826380 DOI: 10.1097/HP.0000000000001688
    The current study was undertaken to investigate the radiological and dosimetric parameters of natural product-based composite (SPI/NaOH/IA-PAE/ Rhizophora spp .) phantoms. The radiological properties of the phantoms were measured at different gamma energies from Compton scatter of photons through angles of 0, 30, 45, 60, 75, and 90 degrees. Ionization chamber (IC) and Gafchromic EBT3 film dosimeters were employed to evaluate the dosimetric characteristics for photons (6-10 MV) and electrons (6-15 MeV). Radiological property results of the composite phantoms were consistent with good quality compared to those of solid water phantoms and theoretical values of water. Photon beam quality index of the SPI15 phantom with p-values of 0.071 and 0.073 exhibited insignificant changes. In addition, good agreement was found between PDD curves measured with IC and Gafchromic EBT3 film for both photons and electrons. The computed therapeutic and half-value depth ranges matched within the limits and are similar to those of water and solid water phantoms. Therefore, the radiological and dosimetric parameters of the studied composite phantom permit its use in the selection of convenient tissue- and water-equivalent phantom material for medical applications.
    Matched MeSH terms: Radiometry/methods
  11. Banjade DP, Tajuddin AA, Shukri A
    Appl Radiat Isot, 2001 Aug;55(2):235-43.
    PMID: 11393765
    Protocols developed for high-energy dosimetry IAEA (Technical Reports Series No. 277, 1997), AAPM (Med. Phys. 10 (1983) 741: Med. Phys. 18 (1991) 73: Med. Phys. 21 (1994) 1251), IPEMB (Phys. Med. Biol. 41 (1996) 2557), and HPA (Phys. Med. Biol. 28 (1983) 1097) have continued to enhance precision in dose measurements and the optimization of radiotherapy procedures. While recent dosimetry protocols, including those due to the IAEA and IPEMB, have made a number of improvements compared with previous protocols, it is further desirable to develop absolute dosimetry methods of dose measurements. Measurements based on careful implementation of procedures contained within the various protocols have been carried out in an effort to determine the extent to which discrepancies exist among the protocols. Dose in water at dmax was measured using cylindrical and parallel-plate ionization chambers for 6 MV photon beams and 5 and 12 MeV electron beams. Results obtained from the use of the AAPM and HPA protocols for 6 MV photon beams were found to be 0.9% larger and 0.1% smaller, respectively, than those measured following the IAEA protocol. Calibration dose measurements for 5 and 12 MeV electron beams in water phantoms were found to agree to within 1%, this being well within recommendations from the ICRU and other sources regarding the accuracy of dose delivery.
    Matched MeSH terms: Radiometry/instrumentation; Radiometry/methods*; Radiometry/standards
  12. Reduan Abdullah, Ahmad Zakaria, Nur Iziana Mohsin, Nik Ruzman Nik Idris, Ahmad Lutfi Yusof, Mazurawati Mohamed
    MyJurnal
    The fi rst part of this study was about measurement of dosimetric parameters for small photon beams to be used as input
    data for treatment planning computer system (TPS) and to verify the dose calculated by TPS in Stereotactic Radiosurgery
    (SRS) procedure. The beam data required were percentage depth dose (PDD), off-axis ratio (OAR) and scattering factor.
    Small beams of 5 mm to 45 mm diameter from a circular cone collimator in SRS were used for beam data measurements.
    Measurements were made using pinpoint ionisation chamber (0.016cc). In the second part of this study, we reported
    the important of carrying out quality assurance (QA) procedures before SRS treatment which were found to infl uence the
    accuracy of dose delivery. These QA procedures consisted of measurements on the accuracy in target localization and
    treatment room laser alignment. The calculated TPS dose for treatment was verifi ed using pinpoint ionisation chamber
    and thermoluminescent detector (TLD) 100H. The deviation mean between measured and calculated dose was -3.28%.
    The measured dose obtained from pinpoint ionisation chamber is in good agreement with the calculated dose from TPS
    with deviation mean of 2.17%. In conclusion, pinpoint ionisation chamber gives a better accuracy in dose calculation
    compared to TLD 100H. The results are acceptable as recommended by International Commission on Radiation Units
    and Measurements (ICRU) Report No. 50 (1994) that dose delivered to the target volume must be within ± 5% error.
    Matched MeSH terms: Radiometry
  13. Mohd Fauzi Haris, Saaidi Ismail, Mohamad Safuan Sulaiman, Mohd Dzul Aiman Aslan, Siti Nurbahyah Hamdan, Maslina Mohd Ibrahim, et al.
    MyJurnal
    The remote measurements of radiation level at an identified location, are not only important for
    collecting data or monitoring radiation level per se, but also crucial for workers who deal with
    radiation sources. A device for checking an on-site radiation level has been developed quite a
    long time ago under the name of Geiger Muller and widely known as a Geiger counter. The
    reading of the output can be seen on the device on-site and on real-time basis. Nowadays, with
    the fast evolution of computer and networking technology, those reading not only can be read
    real-time but also from a remote location that makes workers able to enter the risky area more
    safely. The collected data reading also can be analyzed for predicting the future trending
    pattern. The data is transferred from the monitoring devices to a server through a network. This
    paper discusses about several critical issues on the design, implementation and deployment that
    relates to the devices, interface programs, hardware and software that allow all parameters such
    as radiation levels reading and the timestamp of the data-logging can be collected and stored in
    a central storage for further processes. The compatibility issue with regards to technology
    change from the previous system will also be discussed. The system has many advantages
    compared to previous system and conventional method of doing the area monitoring in term of
    sustainability and availability.
    Matched MeSH terms: Radiometry
  14. Radzi, Z., Abu Kasim, N.H., Yahya, N.A., Abu Osman, N.A., Kassim, N.L.
    Ann Dent, 2008;15(1):33-39.
    MyJurnal
    The purpose of this study was to investigate the light intensity of selected light curing units with varying distance and angulation of the light curing tip and lightmeter. Materials and method: Four types of light units; Spectrum 800 (Dentsply), Coltulux 3 (Coltene), Elipar FreeLight 2 (3M Espe) and Starlight Pro (Mectron) were evaluated for light intensity at various distances between the light curing tip and the radiometer Cure Rite Denstply (0,1,3,5,10 and 15 mm). The light curing units were tested at right angles to the aperture of the light meter and at the angles of 45°, 60° to it at a standardized 5 mm distance. Results: The highest light intensity was obtained when the tip of light curing unit was in contact with the lightmeter aperture. The light intensity decreased significantly when the light tip was placed 5mm, 10mm and 15mm away from the lightmeter aperture. However, no significant differences (p> .05) were detected between Omm, Imm and 3mm. There was a decrease in light intensity when light~·tip was angulated at 45° and 60° except for Coltolux 3. Conclusions: The intensity of the curing light was affected by the distance between the light curing tip and the lightmeter. However, the decrease in light intensity of the light curing unit was found not to obey the inverse square law for the distances 0 to 15 mm. The study found that there was no significant difference between 45° and 60° angulation between the light curing tip and the lightmeter. However, the decrease in light intensity was significant when compared to the light tip placed perpendicular (90°) to the aperture of the light meter.
    Matched MeSH terms: Radiometry
  15. Mohd Fahmi Mohd Yusof, Nur Amirah Nabila Ramli, Mohd Fahrizuan Md Yusop, Reduan Abdullah
    MyJurnal
    This study evaluates the ImageJ software as dosimetric tools for analyzing the film dosimeter in high energy photons and electrons. The percentage depth dose of photons of 6 and 10 MV and electrons of 6 and 9 MeV were measured using the Gafchromic EBT2 film dosimeter. The films were scanned and analyzed using the Verisoft software and ImageJ. The beam profiles at nominal photon and electron beam parameters were also evaluated using the two methods. The PDD measured in ImageJ at high energy photons were in good agreement within 1% percentage of discrepancy at all depths in comparison to the Verisoft software. The PDD measured in ImageJ at high energy electrons also showed good agreement to Verisoft software within 8% percentage of discrepancy at all depths. The measured flatness of beam profiles at Dmax, R50, R80 and R90 in ImageJ were also in good agreement to Verisoft software with flatness value between 4 and 8%. The results indicated the suitability of ImageJ software as dosimetric tool for analyzing EBT2 film dosimeter at high energy photon and electrons.
    Matched MeSH terms: Radiometry
  16. Ullah MH, Islam MT, Faruque MRI
    Materials (Basel), 2013 Nov 06;6(11):5058-5068.
    PMID: 28788376 DOI: 10.3390/ma6115058
    A new meta-surface structure (MSS) with a near-zero refractive index (NZRI) is proposed to enhance the performance of a square loop antenna array. The main challenge to improve the antenna performance is increment of the overall antenna volume that is mitigated by assimilating the planar NZRI MSS at the back of the antenna structure. The proposed NZRI MSS-loaded CPW-fed (Co-Planar Waveguide) four-element array antenna is designed on ceramic-bioplastic-ceramic sandwich substrate using high-frequency structure simulator (HFSS), a finite-element-method-based simulation tool. The gain and directivity of the antenna are significantly enhanced by incorporating the NZRI MSS with a 7 × 6 set of elements at the back of the antenna structure. Measurement results show that the maximum gains of the antenna increased from 6.21 dBi to 8.25 dBi, from 6.52 dBi to 9.05 dBi and from 10.54 dBi to 12.15 dBi in the first, second and third bands, respectively. The effect of the slot configuration in the ground plane on the reflection coefficient of the antenna was analyzed and optimized. The overall performance makes the proposed antenna appropriate for UHFFM (Ultra High Frequency Frequency Modulation) telemetry-based space applications as well as mobile satellite, microwave radiometry and radio astronomy applications.
    Matched MeSH terms: Radiometry
  17. Moradi F, Jalili M, Saraee KRE, Abdi MR, Rashid HAA
    Biomed Phys Eng Express, 2024 Feb 14;10(2).
    PMID: 38320327 DOI: 10.1088/2057-1976/ad26d5
    The inherent biological hazards associated with ionizing radiation necessitate the implementation of effective shielding measures, particularly in medical applications. Interventional radiology, in particular, poses a unique challenge as it often exposes medical personnel to prolonged periods of high x-ray doses. Historically, lead and lead-based compounds have been the primary materials employed for shielding against photons. However, the drawbacks of lead, including its substantial weight causing personnel's inflexibility and its toxicity, have raised concerns regarding its long-term impact on both human health and the environment. Barium tantalate has emerged as a promising alternative, due to its unique attenuation properties against low-energy x-rays, specifically targeting the weak absorption area of lead. In the present study, we employ the Geant4 Monte Carlo simulation tool to investigate various formulations of barium tantalate doped with rare earth elements. The aim is to identify the optimal composition for shielding x-rays in the context of interventional radiology. To achieve this, we employ a reference x-ray spectrum typical of interventional radiology procedures, with energies extending up to 90 keV, within a carefully designed simulation setup. Our primary performance indicator is the reduction in air kerma transmission. Furthermore, we assess the absorbed doses to critical organs at risk within a standard human body phantom protected by the shield. Our results demonstrate that specific concentrations of the examined rare earth impurities can enhance the shielding performance of barium tantalate. To mitigate x-ray exposure in interventional radiology, our analysis reveals that the most effective shielding performance is achieved when using barium tantalate compositions containing 15% Erbium or 10% Samarium by weight. These findings suggest the possibility of developing lead-free shielding solutions or apron for interventional radiology personnel, offering a remarkable reduction in weight (exceeding 30%) while maintaining shielding performance at levels comparable to traditional lead-based materials.
    Matched MeSH terms: Radiometry
  18. Alashrah S, Kandaiya S, Lum LS, Cheng SK
    Z Med Phys, 2013 Dec;23(4):270-8.
    PMID: 24113373 DOI: 10.1016/j.zemedi.2013.09.001
    One of the factors which influence the spatial resolution of a 2D detector array is the size of the single detector, another the transport of the secondary electrons from the walls into the measuring volume. In this study, the single ion chamber dose response function of an I'mRT MatriXX array was determined by comparison between slit beam dose profiles measured with the array and with EBT2 radiochromic film in a solid water-equivalent phantom at a shallow depth of 0.5cm and at a depth of 5cm beyond the depth dose maximum for a 6 MV photon beam. The dose response functions were obtained using two methods, the best fit method and the deconvolution method. At the shallow depth, a Lorentz function and at 5cm depth a Gaussian function, both with the same FWHM of 7.4mm within limits of uncertainty, were identified as the best suited dose response functions of the 4.5mm diameter single array chamber. These dose response functions were then tested on various dose profiles whose true shape had been determined with EBT2 film and with the IC03 ionization chamber. By convolving these with the Lorentz kernel (at shallow depth) and the Gaussian kernel (at 5cm depth) the signal profiles measured with the I'mRT MatriXX array were closely approximated. Thus, the convolution of TPS-calculated dose profiles with these dose response functions can minimize the differences between calculation and measurement which occur due to the limited spatial resolution of the I'mRT MatriXX detector.
    Matched MeSH terms: Radiometry/instrumentation*
  19. Shakhreet BZ, Bauk S, Tajuddin AA, Shukri A
    Radiat Prot Dosimetry, 2009 Jul;135(1):47-53.
    PMID: 19482883 DOI: 10.1093/rpd/ncp096
    The mass attenuation coefficients (mu/rho) of Rhizophora spp. were determined for photons in the energy range of 15.77-25.27 keV. This was carried out by studying the attenuation of X-ray fluorescent photons from zirconium, molybdenum, palladium, silver, indium and tin targets. The results were compared with theoretical values for average breast tissues in young-age, middle-age and old-age groups calculated using photon cross section database (XCOM), the well-known code for calculating attenuation coefficients and interaction cross-sections. The measured mass attenuation coefficients were found to be very close to the calculated XCOM values in breasts of young-age group.
    Matched MeSH terms: Radiometry/methods*
  20. Yusof FH, Ung NM, Wong JH, Jong WL, Ath V, Phua VC, et al.
    PLoS One, 2015;10(6):e0128544.
    PMID: 26052690 DOI: 10.1371/journal.pone.0128544
    This study was carried out to investigate the suitability of using the optically stimulated luminescence dosimeter (OSLD) in measuring surface dose during radiotherapy. The water equivalent depth (WED) of the OSLD was first determined by comparing the surface dose measured using the OSLD with the percentage depth dose at the buildup region measured using a Markus ionization chamber. Surface doses were measured on a solid water phantom using the OSLD and compared against the Markus ionization chamber and Gafchromic EBT3 film measurements. The effect of incident beam angles on surface dose was also studied. The OSLD was subsequently used to measure surface dose during tangential breast radiotherapy treatments in a phantom study and in the clinical measurement of 10 patients. Surface dose to the treated breast or chest wall, and on the contralateral breast were measured. The WED of the OSLD was found to be at 0.4 mm. For surface dose measurement on a solid water phantom, the Markus ionization chamber measured 15.95% for 6 MV photon beam and 12.64% for 10 MV photon beam followed by EBT3 film (23.79% and 17.14%) and OSLD (37.77% and 25.38%). Surface dose increased with the increase of the incident beam angle. For phantom and patient breast surface dose measurement, the response of the OSLD was higher than EBT3 film. The in-vivo measurements were also compared with the treatment planning system predicted dose. The OSLD measured higher dose values compared to dose at the surface (Hp(0.0)) by a factor of 2.37 for 6 MV and 2.01 for 10 MV photon beams, respectively. The measurement of absorbed dose at the skin depth of 0.4 mm by the OSLD can still be a useful tool to assess radiation effects on the skin dermis layer. This knowledge can be used to prevent and manage potential acute skin reaction and late skin toxicity from radiotherapy treatments.
    Matched MeSH terms: Radiometry/instrumentation*
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