Showing papers in "Iranian Journal of Radiation Research in 2014"

Oral zinc sulphate and prevention of radiation-induced oropharyngealmucositis in patients with head and neck cancers: A double blind, randomized controlled clinical trial

Abstract: Background: This research was conducted to evaluate the poten al benefits of zinc sulphate in the preven on of radia on induced mucosi s in pa ents who are being treated for head and neck cancers. Materials and Methods: Forty pa ents with proven cancers of head and neck were randomly divided into 2 equal groups that either received zinc sulphate or placebo (control group). Pa ents who received cura ve radiotherapy or chemoradiotherapy were instructed to take zinc sulphate capsules (30 mg) daily at 8 hours interval. They were to begin 10 days before the start of treatment and con nued un l 2 weeks a er comple ng the schedule. Mucosi s was evaluated weekly according to the Oral Mucosi s Assessment Scale (OMAS). Results: In both groups (zinc and control) mucosi s was evident during the first week but its prevalence was 40% and 70.5% in the zinc and placebo groups respec vely at the end of this period. This difference was significant (p<0.0001). The mean severity of oropharyngeal mucosi s increased a er commencement of radiotherapy and reached to maximum intensity in the 4th week. Control group showed higher severity (p<0.0001). In comparison with the placebo group, the mucosi s score of OMAS in the zinc group was lower un l at 2 weeks a er end of the treatment (p=0.0001). Conclusion: The present study shows that Zinc sulfate is effec ve in reducing the severity of radia on induced oropharyngeal mucosi s. In addi on, it delays the development of mucosi s and may be used at a lower dose (30 mg 3 mes daily) with the same benefit but fewer side effects.

Effective dose from natural background radiation in Keffi and Akwanga towns, central Nigeria

Abstract: Background: Human is exposed to radiaƟ on in their environment with or without their consent; and the exposure to natural background radiaƟ on is an unpreventable event on earth. Materials and Methods: An in situ assessment of the indoor and outdoor background radiaƟ on in Akwanga and Keffi towns of Nasarawa state Nigeria was carried out using a halogen-quenched Geiger Muller (GM) detector (Inspector alert Nuclear radiaƟ on monitor SN: 3544). Each of these towns was divided into at least 20 sampling areas where at least ten readings were taken in order to have a reliable data. Results: The mean indoor and outdoor annual effecƟ ve dose of Akwanga were 1.29± 0.13mSv/yr and 0.31±0.04 mSv/yr respecƟ vely; and that of Keffi were 1.08± 0.15mSv/yr and 0.25±0.04 mSv/yr respecƟ vely. The radiaƟ on levels in both highly populated towns were found to be within the safe limit for areas of normal background set by UNSCEAR (2.4 mSv/yr). Conclusion: These results would serve as a baseline upon which other exposures would be assessed and in the future, serve as reference for dosimetry and decontaminaƟ on in situaƟ ons of radiaƟ on poisoning of these towns.

The basic radiation properties of the N-isopropylacrylamide based polymer gel dosimeter

Abstract: Background: In this study the basic radia on proper es of N‐isopropylacrylamaide polymer gel dosimeter were determined together with verifica on of its so ssue equivalency. Materials and Methods: The NIPAM gel was prepared and irradiated approximately 2 h a er manufacturing. The magne c resonance (MR) images were made 24 h a er irradia on. The nuclear magne c resonance (NMR) response (R2) of the dosimeters was analyzed for condi ons of varying dose, batch, dose rate, me post‐irradia on and energy. In order to verify ssue equivalence of NIPAM dosimeter, several parameters such as physical density, effec ve atomic number, rela ve electron density, CT (Computed Tomography) number and also elemental composi on were determined and compared with those for so ssue. Results: The response of the gel was found to be stable 24 hours a er irradia on. The results showed that the dose response of the NIPAM polymer gel is reproducible in same and different batches of chemical and the gel response was linear up to 26 Gy with r=0.995. In the measured range, the dose response of the NIPAM gel is independent of beam energy within less than ±0.02 and the dose rate had no effect on the gel response. This polymer gel has been found to be ssue equivalent. Conclusion: NIPAM gel dosimeter appears to be a promising dosimeter in all aspects of dosimetric proper es which were assessed in this study, in addi on to the advantage of reduced toxicity which it has over other polymer gels.

Production of a novel high strength heavy concrete using tourmaline and galena for neutron and photon radiation shielding

Abstract: Background: High density concrete is extensively used for efficient radia on a enua on in radiotherapy rooms and nuclear reactors. Over the past eight years, some efficient galena‐based concrete samples for shielding X or gamma rays was produced. The goal of this study was to produce a novel high density concrete against neutron and photon radia ons using tourmaline and galena. Materials and Methods: A enua on of gamma photons was measured using a Farmer type ioniza on chamber with a standard Co buildup cap on a Theratron Co therapy unit. Neutron shielding characteris cs were measured by using an Am‐Be source. The MCNP4C radia on transport computer code was used to inves gate the effects of various shield thicknesses on the a enua on of gamma‐ray photons and neutrons. Results: The concrete samples had a density of 4.0‐ 4.2 g/cm. The compressive strength was 326 ‐ 560 kg/cm. The calculated value for Half Value Layer (HVL) of the tourmaline ‐galena concrete samples for Co gamma rays was 2.72 cm, which is much less than that of ordinary concrete (6.0 cm). The MC‐derived HVL for photons with the same energy was 2.77 cm, which is in a good agreement with the experimental data. Moreover, ToGa concrete had up to 10 mes greater neutron a enua on compared to that of the reference concrete. Conclusion: Tourmalin‐Galena Concrete opens a new horizon in economic and efficient gamma/neutron shielding in high‐energy radiotherapy bunkers, nuclear power plants, and shielding of radioac ve sources.

Protective effect of ferulic acid on ionizing radiation induced damage in bovine serum albumin

Abstract: Background: Ionizing radiaƟ on causes deleterious effects on living system mainly due to oxidaƟ ve damages of macromolecules and protein is the major target due to its abundance. The aim of this study was to invesƟ gate the effects of ionizing radiaƟ on induced changes in the molecular properƟ es of bovine serum albumin (BSA); its secondary and terƟ ary structures, degradaƟ on, cross linking and radioprotecƟ ve role of ferulic acid, a natural anƟ oxidant on these radiaƟ on induced changes. Materials and Methods: This study was carried out to invesƟ gate the gamma radiaƟ on induced oxidaƟ ve, structural damage of BSA and radioprotecƟ ve efficacy of ferulic acid through SDS-PAGE, DTNB assay, DNPH assay, FOX assay methods. Hydroxyl radical scavenging capacity of ferulic acid was esƟ mated using 2-deoxy ribose assay. Further, radiaƟ on induced changes in the anisotropy and excitaƟ on state lifeƟ mes of BSA were examined. Results: SDS -PAGE data suggested that the loss of protein was linearly dependent on the radiaƟ on dose. Gamma-irradiaƟ on of BSA caused the formaƟ on of protein carbonyls, hydroperoxides and loss of thiols . Ferulic acid protected the radiaƟ on induced loss of protein as well as reduced various oxidaƟ ve damages. Ferulic acid protected the protein from radiaƟ on induced damages in a concentraƟ on dependent manner. Conclusion: The results provide insight into radiaƟ on induced molecular changes in the protein. Ferulic acid protected the BSA from oxidaƟ ve modificaƟ on caused by radiaƟ on suggesƟ ng that ferulic acid possesses strong anƟ radical properƟ es. Ferulic acid is known to protect DNA, the prime target of radiaƟ on and further its ability to protect protein suggesƟ ng its ability to protect different biomolecules and therefore can be a good candidate for development radioprotector.

An investigation into the potential applicability of gel dosimeters for dosimetry in boron neutron capture therapy

Abstract: Background: The aim of this work was to establish how well gel dosimeters performed, as subsƟ tutes for brain Ɵ ssue compared with standard phantom materials such as water, polymethyl-methacrylate (or PMMA), A150 plasƟ c and TE- liquid phantom material for dosimetry of neutron beams in boron neutron capture therapy. Materials and Methods: Thermal neutron fluence, photon dose and epithermal neutron dose distribuƟ ons were computed for the epithermal neutron beam of the opƟ mized linac based BNCT. Results: Amongst all invesƟ gated phantom materials, TE-liquid was shown to be a beƩ er subsƟ tute for brain Ɵ ssue than other phantom materials. The differences between TE- liquid and brain at the depth of 6.1 cm for thermal neutron fluence, gamma dose and epithermal neutron dose distribuƟ ons was calculated 2.80%, 2.40% and -13.87% , respecƟ vely. In comparison with the other gel dosimeters, LMD2 provided a beƩ er simulaƟ on of radiaƟ on transport in the brain. It's results differed from the real brain, at the depth of 6.1 cm, for thermal neutron fluence, gamma dose and epithermal neutron dose distribuƟ ons, by -1.27%, 4.20% and 21.05% respecƟ vely. Conclusion: Even though, in gamma dose distribuƟ on the LMD2 has large deviaƟ on from brain Ɵ ssue distribuƟ on, the deviaƟ on is approximately independent of depth, so the results can be mulƟ plied by a constant coefficient to be more consistent with reality. Even though, TE- liquid showed saƟ sfactory results for brain Ɵ ssue subsƟ tuƟ on in BNCT, but some properƟ es of gel dosimeters such as three dimensionality, make LMD2 a potenƟ ally good dosimeter for dosimetric verificaƟ on in BNCT.

Human 3-D tissue models in radiation biology: current status and future perspectives

Abstract: In this review, we discuss the use of a variety of 3-D models (parƟ cularly 3-D skin, lung, breast and endothelial) in radiobiological research and highlight the differences in responses compared to 2-D culturing condiƟ ons (monolayers). We review the characterisƟ cs of exisƟ ng 3-D models and aim to point out the substanƟ al advantages 3-D cultures provide for modern radiobiology. In parƟ cular, they may facilitate the shiŌ from the classical DNA damage and repair studies mainly carried out in monolayer cultures to the invesƟ gaƟ on of more generalized responses through pathway analysis and a system biology approach. 3-D models are expected to be very informaƟ ve for invesƟ gaƟ ons on radiotherapy responses in addressing the low dose risk. However, the 3-D model systems are not as easy to propagate and standardize as monolayer cultures. Therefore, we discuss the problems and limitaƟ ons of 3-D models and propose ways to overcome some of the problems.

Monte Carlo study on beam hardening effect of physical wedges

Abstract: Background: Physical wedges are sƟ ll widely used as beam modifiers in external beam radiotherapy However the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems The aim of this study is to invesƟ gate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value layer, mean energy and Ɵ ssue- phantom raƟ o Materials and Methods: The effect of physical wedges on the photon beam quality of a 6-18MV Varian 2100C/D accelerator was studied with the BEAMnrc Monte Carlo code Good agreements were obtained between measured and calculated depth doses and beam profiles for open and wedged photon beams at both energies Results: It was noƟ ced that for 6 MV photon beams, physical wedges have more significant effects on beam quality than for 18 MV Also it was obtained that at 18 MV photon beam as the wedge angle increased, the effect of wedge on beam quality becomes reversed and beam soŌ ening occurred Conclusion: According to these results, it is recommended that beam hardening and soŌ ening of physical wedges should be considered in treatment planning systems in order to increase the accuracy in dose delivery

Estimation of radiation dose to the lens of eyes of patients undergoing cranial computed tomography in a teaching Hospital in Osun state, Nigeria

Abstract: Background: One of the means of assessing dose to paƟ ents from Computed tomography (CT) procedure is through the determinaƟ on of the skin entrance dose (ESD) with the appreciaƟ on of the concern that ocular exposure effects from CT scan includes possible inducƟ on of cancer and cataract. Due to the relaƟ vely more recent introducƟ on of CT scans, liƩ le work has been done in this area in the country including exposure dose on the lens of the eyes of paƟ ents undergoing Cranial Computed Tomography (C-CT). Materials and Methods: The Entrance Surface Dose (ESD) to the lens of eyes of 26 paƟ ents who had cranial CT procedures at a University Teaching Hospital in Ile-Ife, Nigeria has been determined in order to assess the level of radiaƟ on protecƟ on compliance and opƟ mizaƟ on of radiaƟ on safety at the hospital. Results: Results indicate that the doses to the paƟ ents ranged between 17.13 mGy and 51.98 mGy within the period under study. The average doses obtained for the pediatric paƟ ents (1.5-18 yrs), young adults (19-49 yrs) and adults (≥50 yrs) were 31.14 ±11.02 mGy, 41.81±12.60 mGy and 31.97 ± 11.31 mGy respecƟ vely. The mean dose obtained in this study was lower than threshold for lens damage, therefore the dose recorded in this study is clinically safe. Conclusion: This study represents a requisite pedestal on the need for a naƟ on-wide evaluaƟ on and invesƟ gaƟ on of opƟ mizaƟ on of procedures in radiological examinaƟ ons with a view to establishing a naƟ onal dosimetry protocol and reference dose level or guidance level in the country.

Cesium-137 activity concentrations in soil and brick samples of Mirpur, Azad Kashmir Pakistan

Abstract: Background: The aim of this study was to measure 137 Cs levels in soil and brick samples to set the baseline data and an indicator of fallout radioacƟvity for this part of the world This study will help to probe, if there is any health threat posed by 137 Cs exposure to the residents of the area Materials and Methods: Twenty five samples of soil and 6 samples of bricks were collected from different locaƟons of Mirpur of Azad Kashmir A P‐type HPGe detector was used to measure gamma spectra of samples Results: Results showed that for soil samples acƟvity concentraƟon range from 0076±0071 to 294±017 BqKg ‐1 with average value of 139±017 BqKg ‐1 Similarly acƟvity concentraƟon of 137 Cs in Brick samples range from 022±009 BqKg ‐1 to

Assessment of dose due to natural radio-nuclides in vegetables of high background radiation area in south-eastern part of Bangladesh

Abstract: K in vegetables of a recently found high background radiaƟ on area of south-eastern part of Bangladesh and to detect the radiological risks to human from intake of these vegetables. Materials and Method: 10 plant samples were collected randomly from different locaƟ ons of the study area. The radio-nuclides in papaya were measured by direct γ-ray spectrometry using HPGe detector. Results: The average acƟ vity concentraƟ ons of 226 Ra,

A quality assurance program for an amorphous silicon electronic portal imaging device using in-house developed phantoms: a method development for dosimetry purposes

Abstract: Background: Electronic portal imaging devices (EPIDs) play an important role in radiaƟ on therapy portal imaging, geometric and dosimetric verificaƟ ons. A successful uƟ lizaƟ on of EPIDs for imaging and dosimetric purposes requires a reliable quality control process rouƟ ne to be carried out regularly. In this study, two in-house phantoms were developed and analyzed for implementaƟ on in a quality assurance program for dosimetry purposes. Materials and Methods: An amorphous silicon (a-Si) imager (OpƟ Vue500) was used. A low contrast resoluƟ on phantom and an image quality phantom were constructed and implemented. Low contrast resoluƟ on of the EPID was evaluated by counƟ ng the number of holes detectable in the image of phantom using human observers and a soŌ ware. The image quality phantom was used for modulaƟ on transfer funcƟ on, contrast to noise raƟ o and noise level evaluaƟ ons. This phantom contains five sets of high-contrast rectangular bar paƩ erns of variable spaƟ al frequencies and six uniform regions. Results: Although the manual low contrast resoluƟ on method was observer- dependent and insensiƟ ve to arƟ facts, the automaƟ c method was robust and fully objecƟ ve but sensiƟ ve to arƟ facts. The criƟ cal frequency values for 6 and 18 MV were 0.3558±0.006 lp/mm and 0.2707±0.006 lp/mm respecƟ vely. The contrast-to-noise raƟ o was found to be ~ 240% higher for 6 MV compared to 18 MV. Conclusion: The developed phantoms provide a convenient process for periodic performance of an EPID. These phantoms are independent of the EPID system and provide robust tools for conƟ nuous monitoring of image quality parameters as well as dosimetric parameters.

γ-H2AX as a protein biomarker for radiation exposure response in ductal carcinoma breast tumors: Experimental evidence and literature review

Abstract: Background: H2AX is a histone variant that is systemaƟ cally found and ubiquitously distributed throughout the genome. DNA double-strand breaks (DSBs) induce phosphorylaƟ on of H2AX at serine 139 (γH2AX), an immunocytochemical assay with anƟ bodies recognizing γH2AX has become the gold standard for the detecƟ on of DSBs. The importance of this assay to invesƟ gate different individual responses to gamma irradiaƟ on was reviewed and an example of different radiaƟ on responses of ductal carcinoma tumors with different expression levels of ATM and HER-2 was discussed. Materials and Methods: The ductal carcinoma breast Ɵ ssues were exposed to 4 Gy gamma rays and aŌ er 24 hours incubaƟ on in modified RPMI 1640 medium in 37 °C with CO2, the frequency of residual induced DSB was assessed using γH2AX assay compared to pair normal adjacent and control breast Ɵ ssues. Results: Results showed that the frequency of DSB dramaƟ cally increased in both tumor and normal irradiated Ɵ ssues, compared to sham non-irradiated controls. Tumors with HER-2 over expression showed significantly lower residual DSB frequencies aŌ er 24 hours post irradiaƟ on incubaƟ on Ɵ me, whereas this frequency dramaƟ cally increased in ATM under expressed Ɵ ssues. Conclusion: Our data showed that different Ɵ ssues may have different radio-sensiƟ vity and ATM under- and HER-2 over-expression may lead to higher and lower sensiƟ vity to ionizing radiaƟ on, respecƟ vely. This may be due to the role of ATM in DSB repair and HER-2 in EGFR downstream signaling pathway that with the use of cell survival mechanisms ends to resistance against radiaƟ on effects and acƟ vaƟ on of PI3K/ACT that leads to DSB repair. ABSTRACT�

Three-dimensional gel dosimetry for dose volume histogram verification in compensator-based IMRT

Abstract: Background: Some Ɵ ssues in human body are radiobiologically different from water and these inhomogeneity must be considered in dose calculaƟ on in order to achieve an accurate dose delivery. Dose verificaƟ on in complex radiaƟ on therapy techniques, such as intensity-modulated radiaƟ on therapy (IMRT) calls for volumetric, Ɵ ssue equivalent and energy independent dosimeter. The purpose of this study is to verify a compensator-based IMRT plan in anthropomorphic inhomogeneous phantom by Dose Volume Histograms (DVH) using polymer gel dosimetry. Materials and Methods: An anthropomorphic pelvic phantom was constructed with places for gel inserts. Two aƩ ached cubic inserts for prostate and bladder and a cylindrical insert for rectum. A prostate treatment case was simulated in the phantom and the treatment was delivered by a five field compensator-based IMRT. Gel dosimeters were scanned by a 1.5 Tesla magneƟ c resonance imaging (MRI). Results were analyzed by DVH and difference of differenƟ al DVH. Results: Results showed for 3D compensator-based IMRT treatment plan for prostate cancer, there was overall good agreement between calculated dose distribuƟ ons and the corresponding gel measured especially in planning target volume (PTV) region. Conclusion: Our measurements showed that the used treatment plan configuraƟ on has had clinically acceptable accuracy and gel dosimetry can be considered as a useful tool for measuring DVH. It may also be used for quality assurance and compensator-based IMRT treatment verificaƟ on.

Natural ventilation considerations for radon prone areas of Ramsar

Abstract: Background: In Iran, architectures are o
Len unaware of the risk of radon inhala
Ÿon and how to reduce radon levels. Furthermore, radon considera
Ÿons are not implemented in construc
Ÿon methods, construc
Ÿon materials and building u
Ÿliza
Ÿon by regulatory authori
Ÿes. Materials and Methods: In this study a
Ler reviewing the meteorological changes of Ramsar over the past 50 years (1955‐2005), a novel design for construc
Ÿng dwellings in radon prone areas is introduced. Out of building interven
Ÿons such as plan
Ÿng wind‐tunnel‐making trees will be discussed in another paper. Ramsar soil samples with 4 levels of specific ac
Ÿvi
Ÿes (extremely hot, severely hot, very hot, and hot) were placed in a model house. Radon level monitoring was performed by using a PRASSI portable radon gas survey meter. Results: For extremely hot soil samples, the radon levels inside the model house when windows were closed for 24 hours were 1615 ±516 Bq/m 3 . When windows which were in the wind direc
Ÿon or opposite the wind direc
Ÿon were opened for 24 h, the radon level decreased to 89 ±286 and 139 ±314 Bq/m

Alterations of PSA, CA15.3, CA125, Cyfra21-1, CEA, CA19.9, AFP and Tag72 tumor markers in human blood serum due to long term exposure to high levels of natural background radiation in Ramsar, Iran

Abstract: Background : Ramsar (Mazandran province) is known for its extremely high levels of natural background radia
Ÿon. Although no excess cancer rate is reported in these areas by epidemiological studies, the study of tumor markers in the inhabitants of these areas may shed some light on the impact of high levels of background radia
Ÿon on cancer induc
Ÿon. Materials and Methods : The level of background gamma radia
Ÿon as well as indoor radon was determined using RDS‐110 and CR‐39 dosimeters. Thirty five individuals from a high background radia
Ÿon area (HBRA) and 53 individuals from a normal background radia
Ÿon area (NBRA) were randomly selected to par
Ÿcipate in the study. Commercial ELISA kits (sandwich type ELISA tests) were used to measure the serum levels of PSA, CA15.3, CA125, Cyfra21‐1, CEA, CA19.9, AFP and Tag72 tumor markers. Results : Among the eight biomarkers inves
Ÿgated, the means of PSA, CA15.3, CA125, CA19.9 and AFP concentra
Ÿons between the HBRAs and NBRAs were not significantly different. However, Cyfra21, CEA and Tag72 in HBRA group revealed sta
Ÿs
Ÿcally significant increases compared to those of NBRA group (P<0.05). Furthermore, a sta
Ÿs
Ÿcally significant correla
Ÿon between the external gamma dose as well as indoor radon level and the concentra
Ÿon of CEA (P<0.001), Cyfra‐21(P<0.001) and TAG 72 (P<0.001 and 0.01 respec
Ÿvely) biomarkers were observed.

Lessons learnt from errors in radiotherapy centers

Abstract: Background: The purpose of this work is to discover and analyze errors and incidents in some radiotherapy centers, and to introduce methods that could reduce their occurrences, especially those which had happened due to the use of improper and inadequate equipment. This work is a first step toward clarifying the role of educaƟon in a risk-conscious culture, and changing the aƫtude of radiotherapy staff when they are working under encouraging condiƟons that remove barriers for reporƟng errors. Materials and Methods: For the present study clinical invesƟgaƟon, the data of 6000 paƟents were checked. They were treated at a few radiotherapy centers during one year. PaƟents were treated by linear accelerator or cobalt machine, photon or electron beams. A purposely designed check list was used for error data collecƟon. Incidents were discovered by manual check at different steps of treatment. By highlighƟng frequency of occurrence, further invesƟgaƟon for prevenƟng error repeƟƟ on can be possible. Eighty five incidents were reported by Technologists, fiŌy four were reported by Physicists, and twenty six events were pointed out by RadiaƟon Oncologists. Results: About fiŌy percent of total 165 detected events were classified as treatment field errors. Geometrical misses in treatment field have the highest probability for both photon and electron beams. Conclusion: Incident prevenƟon considering likelihood of individual event can be possible when using faciliƟes like record- and-verificaƟon (R&V) system and electronic-portal-image-device (EPID), taking seriously QA, defining and implemenƟng layers of defense in depth, and making an organized system for reporƟng and analyzing errors.

Optimum reckoning of contra lateral breast dose using physical wedge and enhanced dynamic wedge in radiotherapy treatment planning system

Abstract: Background: It was intended to invesƟgate the effect of physical wedge (PW) and enhanced dynamic wedges (EDW) on contralateral breast dose during primary breast irradiaƟon in radiotherapy treatment, using high energy photon beams. Materials and Methods: The Varian's Clinac dual mode linear accelerator model 2100 C/D and Siemen's Primus accelerators were used for radiaƟon doses with 6 MV and 15 MV. Doses were delivered using TangenƟal field techniques and asymmetric collimator jaws. Eclipse three-dimensional Treatment Planning System (3DTPS) was used to measure contralateral breast dose for all fiend seƫngs. Sixty five paƟents (with cancerous breast as well as chest wall) were taken and their contralateral breast doses were measured at a point 5 cm across, at 2 cm depth from the end of the medial field. Results: The contralateral breast dose mean difference was 0.25 cGy and 0.24 cGy during the comparison of PW and EDW on Varian's Clinac and 0.19 cGy and 0.18 cGy were found for medial EDW and without medial EDW for the same machine in breast cases and chest wall cases respecƟvely as per total prescribed dose. The mean difference for PW (Clinac) and PW (Primus) was found 0.08 cGy and 0.31 cGy and during the comparison of medial PW and without medial PW on primus machine this mean difference was 0.25 cGy and 0.51 cGy in breast cases and chest wall cases respecƟvely as per total prescribed dose. Conclusion: The invesƟgaƟon demonstrates the significance that the EDW produces less scaƩered dose, which can cause second breast malignancy, compared to PW. Furthermore, the medial wedge, too, can cause second breast malignancy and should be avoided in planning.

Design of homogeneous and heterogeneous human equivalent thorax phantom for tissue inhomogeneity dose correction using TLD and TPS measurements

Abstract: Background: The purpose of this study is to fabricate inexpensive in-house low cost homogeneous and heterogeneous human equivalent thorax phantom and assess the dose accuracy of the Treatment Planning Systems (TPS) calculated values for different lung treatment dosimetery. It is compared with Thermoluminescent Dosimeter (TLD) measurement. Materials and Methods: Homogeneous and heterogeneous thorax human equivalent phantoms were fabricated using bee's wax (density=0.99 g/cm 3 ) as a Ɵ ssue simulaƟ ng material, with inserts of cork (density=0.2 g/cm 3 ) and Teflon (density=2 g/cm 3 ) as lung and spine simulaƟ ng material respecƟ vely. Lithium fluoride (LiF) TLD capsules were irradiated for different thoracic tumor treatment techniques using the locally fabricated homogeneous and heterogeneous phantoms. The 3D TPS calculated values of homogeneous and heterogeneous phantoms were compared with TLD measured values. Results: Experiments were carried out for different thoracic tumour treatment techniques for small and larger field sizes and also with and without wedge for Cobalt - 60 photon beams. Plato TPS were used to calculate the inhomogeneity for the homogeneous and heterogeneous phantoms. TLD and 3D TPS calculated values were found to have deviaƟ on of ± 5%. Conclusion: Both the homogeneous and heterogeneous phantoms has proved to be a valuable tools in the development and implementaƟ on of external beam radiotherapy (EBRT) in the clinical thorax region and in the verificaƟ on of absolute dose and dose distribuƟ ons in the regions of clinical and dosimetric interest.

HVL evaluation of orthovoltage X-ray machine using EGSnrc code of simulation

Abstract: Background: Making use of the orthovoltage machines in Radiotherapy, is one of the rouƟ ne methods for the treatment of the superficial lesions. In this study, an important determinant of X-ray quality, the HVL (Half Value Layer), has been evaluated. Materials and Methods: The HVLs of a orthovoltage X- ray machine in 120 and 180 kVp are measured, using an empirical method, in which the HVLs are derived from the absorpƟ on curves. The measured HVLs are compared with calculated (Monte Carlo simulaƟ on) HVLs. Using the BEAMDP code of simulaƟ on, the output spectra are obtained and employed for the measurement of the HVLs. Results: Comparing the calculated and measured HVL values, the results show that the highest and lowest differences between the two are 4.96% and 2.27%, respecƟ vely, which are, in fairly good agreement with those obtained in the former studies. Conclusion: This study shows that the EGSnrc simulaƟ on code is capable of being used for the extracƟ on of the quality indices for the superficial X-ray radiotherapy machines. It seems that, the menƟ oned code, with the menƟ oned experimental method, can be employed as a rouƟ ne clinical test tool for every superficial radiotherapy department.

Dose measurement outside of radiotherapy treatment field (Peripheral dose) using thermoluminesent dosimeters

Abstract: Background: In radiaƟ on therapy, peripheral dose or the dose outside the radiotherapy field, is important when anatomic al structures with very low dose tolerances are involved. One of these criƟ cal organs in pelvic irradiaƟ on is tesƟ s. The amount of radiaƟ on delivered to the testes in radiotherapy must be kept as small as possible, consistent with the limit dose of this organ. The threshold doses for temporary and permanent sterility are 0.15 Gy and 6-8 Gy, respecƟ vely. Therefore, in pelvic irradiaƟ on, protecƟ ng tesƟ s from these doses and also scaƩ ered radiaƟ on which could escalate tesƟ s dose should be considered. Materials and Methods: In order to determine the possibility of using tesƟ cular shield for high and low energies, TLD dosimetry was done on phantom and 27 paƟ ents involved with bladder, rectum and prostate cancers. Results: Dosimetric results showed that the ability of tesƟ cular shield in reducing testes absorbed dose is approximately the same (about 7 cGy) for low and high energy photon beams. Conclusion: a tesƟ cular shield with a fixed thickness of 1.27cm can be used as tesƟ s protecƟ on for either high and low energies. *Correspondingauthor:� Dr.�HassanAliNedaie,� Fax:�+98�21�66948673� E-mail:�

Prostate IMRT: Two-dimensional model of rectal NTCP employing the variability of rectal motion and rectum wall thickness

Abstract: Background: In order to improve the evaluaƟon of possible rectal toxicity based on the rectal normal Ɵ ssue complicaƟon probability (NTCP), we consider the fracƟonal dependence of the NTCP on the wall thickness (tW) and rectal displacement (RM). Materials and Methods: The two-dimensional NTCP model (NTCP2D) was developed using radiotherapy plans of ten randomly selected paƟents with prostate cancer. The clinical rectal structures were subsƟtuted with rectal walls of cylindrical shape. To simulate full, parƟally-full and empty state of the rectum, three tW were generated under the condiƟons of same length of the rectum and same volume of the rectal wall. A threshold iso-line, NTCPTR, was used to split the NTCP2D field into areas: a lower risk area and a higher risk area for rectal toxicity. Two factors are introduced to help with the esƟmaƟon of NTCP: a volume factor k1 which is the raƟo between the volumes of the rectal wall and the intersecƟon of the rectal wall with the planning target volume; and a probability factor k2, which is the raƟo between the area of low risk to the enƟre area of the NTCP2D. Results: A correlaƟon > 0.9 between factors k1 and k2 was found. Conclusion: The NTCP2D field and the raƟos k1 and k2 can be used as a paƟent-specific parameters to evaluate the probability of rectal toxicity.

Impact of range straggling and multiple scattering on proton therapy of brain, using a slab head phantom

Abstract: Background: The advantages of proton beam in radiaƟ on therapy- like small lateral scaƩ ering as well as absence of exit dose tail in the organs which are aŌ er the tumor- make it capable of delivering more treatment doses to the target and much lesser to the criƟ cal Ɵ ssues near it. Materials and Methods: In this study, the Monte Carlo MCNPX code has been used to simulate a slab head phantom irradiated by proton pencil beams. The simplified slab has Ɵ ssue composiƟ ons of the ICRU 46, and the necessary data have been taken from adult male phantom of MIRD-ORNL family series. Results: Suitable energy range of incident proton beams has been esƟ mated in order to have the Bragg peaks inside the brain Ɵ ssue. Energy straggling or, rather, range straggling, and mulƟ ple scaƩ ering which affect the lateral broadening of incident beams, have been invesƟ gated. Conclusion: The results show that the FWHM (Full Wide in Half Maximum) increases more than six Ɵ mes from 1.73 mm to 10.78 mm for the energy range of 50 - 135 MeV. The FWHM values of lateral dose profiles change from 1 mm in 50 MeV to 7.5 mm in 135 MeV, and it has been shown that when a pencil beam is used to irradiate a Ɵ ssue, the absorbed dose in depth along the central axis does not show a Bragg peak paƩ ern.

Assessment of molybdenum breakthrough levels in molybdenum-99/technetium-99m generators: one year experience at nimra jamshoro pakistan

Abstract: Background: TechneƟ um-99m radioisotope is the backbone of any nuclear medicine insƟ tute. This radioisotope is acquired by the eluƟ on of Molybdenum-99/TechneƟ um-99m generator which emits 141 keV gamma ray and having 6.04 hour half-life. Occasionally the contents of Molybdenum- 99 may mix up with elute, which may affect image quality and paƟ ents may receive higher doses than recommended. This study was iniƟ ated to check and evaluate the contaminaƟ on of Molybdenum-99 in Molybdenum-99/ TechneƟ um-99m generators used at Nuclear InsƟ tute of Medicine and Radiotherapy (NIMRA) Jamshoro Pakistan before its administraƟ on to paƟ ents for diagnosƟ c procedures. Materials and Methods: The Molybdenum-99 impurity in TechneƟ um-99m elute for 50 generators was studied during the year 2012. The measurements were made using dose calibrator and a standard canister at the Ɵ me of first eluƟ on of the generators. The dose calibrator displays result aŌ er execuƟ ng various steps in a sequence. Due to some producƟ on process error or any mechanical fault high acƟ vity of Molybdenum-99 was recorded and removed with decrease in TechneƟ um-99m yield. Results: The most of eluted generators (90%) contained 10% of molybdenum breakthrough of the permissible limit (P < 0.05). The high acƟ vity of Molybdenum-99 was recorded in only 6% of the generator and removed by using standard methods with some reduced TechneƟ um-99m acƟ vity. Conclusion: The molybdenum breakthrough was according to recommended standards in most of the generators. The removal of high contents of Molybdenum-99 enabled the insƟ tute to conƟ nue rouƟ ne imaging services by improved image quality and reducƟ on in radiaƟ on dose to the paƟ ents.

Calibration and optimization of a low cost diffusion chamber for passive separated measurements of radon and thoron in soil by Lexan PC SSNTD

Abstract: Background: Separate radon and thoron measurements in soil are very important in assessment of internal exposure due to inhalaƟon of such radioacƟve gases. Materials and Methods: In this study, a low cost, small size, passive diffusion chamber has been developed for simple measurement of Radon-222 and Radon-220(Thoron) gases separately in soil. The diffusion chamber consists of two films and two fiber glass filters. Lexan polycarbonate films were used as Solid State Nuclear Track Detectors (SSNTDs) and opƟmized film to filter distance was obtained. Results: CalibraƟon factors for the designed diffusion chamber were measured using flow through method which was 16.85(track.cm -2 (kBq.

Determination of 226Ra concentration in bottled mineral water and assessment of effective doses, a survey in Turkey

Abstract: Background: There is a rapid increase worldwide in the consump on of mineral waters which may contain different level of radioac ve elements, especially Ra, in addi on to varying amounts of beneficial salts. Therefore, a comprehensive study was planned and carried out in order to determine concentra on of Ra natural radionuclide in bo led mineral waters that commercially available in Marmara Region of Turkey. Materials and Methods: The method used for Ra concentra on analysis bases on the measurement of Radon (Rn) coming from Ra dissolved in the water. The measurements were performed using RAD 7, a solid state α detector, with RAD H2O accessory manufactured by DURRIDGE COMPANY Inc. Results: The Ra concentra on in mineral waters was found to vary from <0.074 to 0.625 Bql with an average value of 0.267 Bql.The commi ed effec ve doses due to inges on of Ra from the one year consump on of these waters were es mated to range from 10.8 to 90 μSvy, from 9 to 75 μSvy and from 3.15 to 26.25 μSvy, for infants, children and adults, respec vely. Conclusion: The results obtained in this study indicate that the commi ed effec ve doses are below the WHO (World Health Organiza on) recommended reference level of 100 μSvy.

Radioprotective efficacy of prunus avium fruit in mice brain with reference to in-vitro and in-vivo studies

Abstract: Background: RadioprotecƟ ve efficacy of Prunus avium fruit extract (PAE) rich in vitamin A, C, E and anthocyanin was studied against radiaƟ on induced biochemical alteraƟ ons in mice brain. Materials and Methods: In-vitro assays were performed with PAE for its anƟ oxidant studies; thereaŌ er for in-vivo study, Swiss albino mice were divided into five groups. Group 1 (control) normal mice. Group 2 (PAE treated) PAE supplemented (450 mg/kg. b.wt/day) for 15 days. Group 3 (Irradiated) 5 Gy gamma-radiaƟ on treated. Group 4 (PAE + Irradiated) was administered PAE once daily for 15 consecuƟ ve days, thereaŌ er exposed to 5 Gy gamma-radiaƟ on. Group 5 (Irradiated + PAE) was exposed to 5 Gy gamma-radiaƟ on than PAE was administered for 15 consecuƟ ve days. Brains were removed at various post treatment intervals for biochemical esƟ maƟ ons. Results: The IC50 values of PAE for 2,2-diphenyl-1 -picrylhydrazyl (DPPH ·) scavenging assays, superoxide radical scavenging assays, inhibiƟ on of in vitro lipid peroxidaƟ on assays and protein carbonyl formaƟ on assay were 413 µg/ml, 7.63 µg/ml, 136.18 µg/ml and 16.94 µg/ml respecƟ vely. Furthermore the total phenolic content in PAE was equivalent to 8.38 mg/ml of gallic acid. The rate of · OH radical scavenging acƟ vity of PAE was 0.57 Ɵ mes slower than SCN - derived from nanosecond pulse radiolysis studies. In-vivo study also showed that radiaƟ on (5 Gy) induced augmentaƟ on in the levels of lipid peroxidaƟ on and depleƟ on in glutathione and protein level in mice brain were significantly ameliorated by PAE pre/post treatment. Conclusion: Results suggest that the radioprotecƟ ve efficacy of PAE may be due its anƟ oxidant property.

Production of yttrium aluminum silicate microspheres by gelation of an aqueous solution containing yttrium and aluminum ions in silicone oil

Abstract: Background: RadioacƟ ve yƩ rium glass microspheres are used for liver cancer treatment. These yƩ rium aluminum silicate microspheres are synthesized from yƩ rium, aluminum and silicone oxides by melƟ ng. There are two known processes used to transform irregular shaped glass parƟ cles into microspheres, these 'spheroidizaƟ on by flame' and 'spheroidizaƟ on by gravitaƟ onal fall in a tubular furnace'. Materials and Methods: YƩ rium aluminum silicate microspheres with the approximate size of 20-50 µm were obtained when an aqueous soluƟ on of YCl3 and AlCl3 was added to tetraethyl orthosilicate (TEOS) and pumped in to silicone oil and sƟ rred constantly the temperature of 80˚C. The resulƟ ng spherical shapes were then invesƟ gated for crystallizaƟ on, chemical bonds, composiƟ on and distribuƟ on of elements by scanning electron microscopy (SEM), X-ray diffracƟ on (XRD), Fourier transform infrared spectroscopy (FTIR), carbon/sulfur analysis, X-ray photoelectron spectroscopy (XPS) and SEM/EDS analysis. Results: The parƟ cles produced by the above-menƟ oned method were regular and nearly spherical in shape. The results of topographical analysis of a cross-secƟ on showed that form of the microspheres had formed a 'boiled egg' structure. This method has an advantage over other methods in that the process does not require high temperatures. Conclusion: This paper reports on a novel method to produce yƩ rium glass microspheres. The resulƟ ng microspheres were formed with a silicon crust so the proposed method is expected to be suitable for applicaƟ on in the producƟ on of radioacƟ ve seed sources for implantaƟ on in tumors and cancer Ɵ ssue.

Effect of uniform magnetic field on dose distribution in the breast radiotherapy

Abstract: Background: To reduce the dose to normal Ɵ ssues surrounding the treated breast, a uniform magneƟ c field was used within a humanoid phantom in breast radiotherapy. Materials and Methods: Monte Carlo simulaƟ ons were performed with GEANT4, irradiaƟ ng humanoid phantoms in a magneƟ c field. To reconstruct phantoms, computed tomography (CT) data slices of four paƟ ents were used for the Monte Carlo simulaƟ ons. All of them had leŌ breast cancer either or not mastectomy. In the simulaƟ ons, the planning and methods of chest wall irradiaƟ on were similar to the actual clinical planning. Results: UƟ lizing magneƟ c field will help to produce uniform dose distribuƟ on to the breast with a sharp dose-volume histogram (DVH) curve for the planning target volume (PTV), however, for the ipsilateral lung and chest wall skin the mean dose was reduced by a mean of 16% and 12% at 1.5 T, and 9% and 7% at 3 T, respecƟ vely. The magneƟ c field was shown to restrict the lateral spread of secondary electrons to the contralateral organs, resulƟ ng in significient dose reducƟ ons to the contralateral breast (CB) and contralateral chest wall skin (CCWS) by a mean (range) of 28% (21-37%) and 58% (44-75%) at 1.5 T, and 48% (32-81) and 66% (54-73%) at 3 T, respecƟ vely. Conclusion: The simulaƟ ons established that the magneƟ c field can reduce the dose to the internal and contralateral Ɵ ssues and increase it to the PTV with sharper edge DVH curve.

Successful treatment of inflammatory myofibroblastic tumor by surgical resection and radiotherapy: A case report

Abstract: Background: Inflammatory myofibroblasƟ c tumor (IMT) is a tumor composed of myofibroblasts and a mixed inflammatory infiltrate that rarely undergoes malignant transformaƟ on. The most common sites of involvement include the lung, liver and orbit, but it has been reported to occur in nearly every site of the body, including oral cavity and soŌ Ɵ ssue. Although common in other sites, such a tumor in rarer locaƟ on including inguinal region is likely to be missed/misdiagnosed and hence need to be reported. Case Report: We present an unusual case of a 50 year old male with bilateral inguinal swelling aƩ ended our insƟ tute few days back with history of local excision twice, but sƟ ll showing recurrence. He was treated by wide local excision with bilateral orchiectomy this Ɵ me. Histopathological report revealed inflammatory myofibroblasƟ c tumor with malignant transformaƟ on. Adjuvant radiotherapy was also given and paƟ ent taken in followup. At one year of serial follow-ups, the paƟ ent is disease-free both clinically and on invesƟ gaƟ ons, indicaƟ ng successful combined surgery and radiotherapy in the treatment of malignant IMT. Conclusion: IMT of the inguinal region is very rare. Its clinical presentaƟ on may resemble malignant tumor, so IMT should be kept as differenƟ al diagnosis. The recommended treatment is complete surgical resecƟ on with adjuvant corƟ costeroid. Adjuvant radiotherapy may be considered depending upon the locaƟ on of the tumor.