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• Four interventional X-ray systems were tested with up to 8 skin dose mapping products. • SDM software can make considerable error in specific conditions. • No SDM product provided estimates within 40% for all set-ups and systems. • Few SDM products provided estimates within 40% for all set-ups on a specific system. • Establishing a common QC protocol for testing SDM products is currently unachievable. Online and offline software products can estimate the maximum skin dose (MSD) delivered to the patient during interventional cardiology procedures. The capabilities and accuracy of several skin dose mapping (SDM) software products were assessed on X-ray systems from the main manufacturers following a common protocol. Skin dose was measured on four X-ray systems following a protocol composed of nine fundamental irradiation set-ups and three set-ups simulating short, clinical procedures. Dosimeters/multimeters with semiconductor-based detectors, radiochromic films and thermoluminescent dosimeters were used. Results were compared with up to eight of 10 SDM products, depending on their compatibility. The MSD estimates generally agreed with the measurements within ± 40% for fundamental irradiation set-ups and simulated procedures. Only three SDM products provided estimates within ± 40% for all tested configurations on at least one compatible X-ray system. No SDM product provided estimates within ± 40% for all combinations of configurations and compatible systems. The accuracy of the MSD estimate for lateral irradiations was variable and could be poor (up to 66% underestimation). Most SDM products produced maps which qualitatively represented the dimensions, the shape and the relative position of the MSD region. Some products, however, missed the MSD region when situated at the intersection of multiple fields, which is of radiation protection concern. It is very challenging to establish a common protocol for quality control (QC) and acceptance testing because not all information necessary for accurate MSD calculation is available or standardised in the radiation dose structured reports (RDSRs). [ABSTRACT FROM AUTHOR]

• Prone position delivers relatively a lower skin dose than supine treatment technique. • Prone position can lead to lower dose in lumpectomy close to skin. • Skin dose needs to be evaluated in breast patients. • Lower dose to Organs at Risk in prone position compared to the supine position. • Skin dose in breast cancer radiation treatment is critical for the outcomes and cosmesis. To determine how the skin dose varies in patients receiving radiation treatment for breast cancer in the prone and supine positions. Fifty patients were scanned in the prone and supine positions. A radiation treatment plan was created for the left breast using a 6-MV beam for a prescribed dose of 42.66 Gy in 16 fractions. The dose was calculated using 1- and 2.5-mm calculation grid sizes and the surface dose was compared in both techniques. The median gantry angles relative to the skin surface at the central axis were 8 and 52 degrees for treatment in the prone and supine positions, respectively. The mean dose difference between the prone and supine techniques was statistically significant from 3- to 5-mm depth for both grid sizes. For the 1-mm calculation grid size, the doses at 3-, 4-, and 5-mm depths in the prone and supine techniques were 87.80% and 89.10% (P < 0.003), 91.92% and 94.50% (P < 0.00), and 95.30% and 98.20% (P < 0.00), respectively; for the 2.5-mm grid size, the respective doses were 87.10% and 88.59% (P < 0.00), 91.60% and 94.63% (P < 0.00), and 95.10% and 97.80% (P < 0.00), respectively. This study demonstrates that the prone technique facilitates a relatively lower skin dose than the supine technique. This observation is probably due to the beam angle. The beam is more perpendicular to the skin surface in the prone technique, whereas it is more tangential in the supine technique, which may deliver a higher skin dose. Thus, the dose to the skin should be evaluated in the prone technique, and if desired, the skin dose could be carefully augmented via a bolus or beam spoiler. [ABSTRACT FROM AUTHOR]

Objective. This study aimed to develop a new approach to predict radiation dermatitis (RD) by using the skin dose distribution in the actual area of RD occurrence to determine the predictive dose by grade. Approach. Twenty-three patients with head and neck cancer treated with volumetric modulated arc therapy were prospectively and retrospectively enrolled. A framework was developed to segment the RD occurrence area in skin photography by matching the skin surface image obtained using a 3D camera with the skin dose distribution. RD predictive doses were generated using the dose-toxicity surface histogram (DTH) calculated from the skin dose distribution within the segmented RD regions classified by severity. We then evaluated whether the developed DTH-based framework could visually predict RD grades and their occurrence areas and shapes according to severity. Main results. The developed framework successfully generated the DTH for three different RD severities: faint erythema (grade 1), dry desquamation (grade 2), and moist desquamation (grade 3); 48 DTHs were obtained from 23 patients: 23, 22, and 3 DTHs for grades 1, 2, and 3, respectively. The RD predictive doses determined using DTHs were 28.9 Gy, 38.1 Gy, and 54.3 Gy for grades 1, 2, and 3, respectively. The estimated RD occurrence area visualized by the DTH-based RD predictive dose showed acceptable agreement for all grades compared with the actual RD region in the patient. The predicted RD grade was accurate, except in two patients. Significance . The developed DTH-based framework can classify and determine RD predictive doses according to severity and visually predict the occurrence area and shape of different RD severities. The proposed approach can be used to predict the severity and shape of potential RD in patients and thus aid physicians in decision making., (© 2024 Institute of Physics and Engineering in Medicine.)

• Evaluation of a novel high-density bolus alternative to tissue-equivalent Superflab. • eXaSkin, the novel bolus, had superior adaptation to the skin surface. • eXaSkin allowed for accurate positioning and reproducibility of set-up conditions. • eXaSkin provided sufficient build-up to achieve full skin dose with less material. To evaluate eXaSkin, a novel high-density bolus alternative to commercial tissue-equivalent Superflab, for 6MV photon-beam radiotherapy. We delivered a 10 × 10 cm2 open field at 90° and head-and-neck clinical plan, generated with the volumetric modulated arc therapy (VMAT) technique, to an anthropomorphic phantom in three scenarios: with no bolus on the phantom's surface, with Superflab, and with eXaSkin. In each scenario, we measured dose to a central planning target volume (PTV) in the nasopharynx region with an ionization chamber, and we measured dose to the skin, at three different positions within the vicinity of a neck lymph node PTV, with MO Skin ™, a semiconductor dosimeter. Measurements were compared against calculations with the treatment planning system (TPS). For the static field, MO Skin results underneath the eXaSkin were in agreement with calculations to within 1.22%; for VMAT, to within 5.68%. Underneath Superflab, those values were 3.36% and 11.66%. The inferior agreement can be explained by suboptimal adherence of Superflab to the phantom's surface as well as difficulties in accurately reproducing its placement between imaging and treatment session. In all scenarios, dose measured at the central target agreed to within 1% with calculations. eXaSkin was shown to have superior adaptation to the phantom's surface, producing minimal air gaps between the skin surface and bolus, allowing for accurate positioning and reproducibility of set-up conditions. eXaSkin with its high density material provides sufficient build-up to achieve full skin dose with less material thickness than Superflab. [ABSTRACT FROM AUTHOR]

To establish skin dose–outcome relationships using a reliable metric in permanent breast seed implant (PBSI). Sixty-seven consecutive patients who underwent PBSI at our institution were included. Skin doses were calculated using two skin dose indices: maximum point dose to the skin surface, D max , and D 0.2cc for a 2-mm internal skin rind (a surrogate to the dose to 1 cm2 area of skin) from CT-based postoperative treatment plans. Toxicity data were extracted from patients' charts and photographs. The associations between skin dose and skin toxicity were investigated using the analysis of variance, and the predictive performance of skin dose measures was evaluated using receiver operating characteristic curves. For acute reactions, 49.3% of patients had Grade 1, 4.5% Grade 2, and 1.5% Grade 3 toxicity. For telangiectasia at 3 years, very minor and minimally apparent telangiectasia was observed in 25% of patients. Moderate but asymptomatic telangiectasia was observed in 9.1% of cases. Both metrics were significantly associated with the occurrence of acute toxicity and telangiectasia at 3 years (p < 0.01). The predictive values for D max and D 0.2cc were 0.779 and 0.763, respectively, (p < 0.0001) for acute skin toxicity and 0.786 and 0.810 for telangiectasia (p < 0.0002). Extreme dose outliers (up to 878 Gy) and a high variability were observed for D max but not for D 0.2cc , illustrating the superior reliability of D 0.2cc. D 0.2cc , as an alternate skin dose measure to D max , is a robust metric for measuring skin dose that is simple to calculate, yet is clinically relevant and not prone to inaccuracies inherent to point dose measurement. [ABSTRACT FROM AUTHOR]

Background: Layer-stacking irradiation (LSI) results in the accumulation of multiple small spread-out Bragg peaks along the beam direction. Although the superiority of LSI to conventional passive irradiation (CPI) regarding normal tissue sparing is theoretically evident, the clinical benefit of LSI has not been demonstrated. Here, we compared LSI with CPI using the same treatment planning-computed tomography images used for carbon ion radiotherapy (CIRT). Methods: Twenty-one parotid tumors were analyzed. The clinical target volume (CTV) 1 and CTV2 encompassed the parotid grand and the tumor, respectively. CTV1 and CTV2 received 36 Gy (RBE: relative biological effectiveness) in nine fractions and 64 Gy (RBE) in 16 fractions, respectively, using either LSI or CPI. CTV coverage was assessed by DX%, which is the dose covering at least X% of the target volume. Skin dose was assessed by SX, which is the skin surface area receiving at least X Gy (RBE). Results: For CTV1 and CTV2, there were no significant differences in D2% between LSI and CPI. D50% and D98% were slightly higher for CPI; however, the absolute difference between the two methods was <3%. S10–S60 (in increments of 10) were significantly lower for LSI than for CPI (P < 0.001 for all parameters). LSI was associated with a significant trend toward dose reduction at the skin area irradiated with a higher dose by CPI (P < 0.001). Conclusions: LSI achieved better skin sparing than CPI without sacrificing target volume coverage in parotid tumor patients. [ABSTRACT FROM AUTHOR]

Purpose: This study was designed to evaluate skin dose in both VMAT and tangent treatment deliveries for the purpose of identifying suitable bolus use protocols that should produce similar superficial doses. Methods: Phantom measurements were used to investigate skin dose in chest wall radiotherapy with and without bolus for 3D and rotational treatment techniques. Optically stimulated luminescence dosimeters (OSLDs) with and without housing and EBT3 film were used. Superflab (3, 5, and 10 mm) and brass mesh were considered. Measured doses were compared with predictions by the Eclipse treatment planning system. Patient measurements were also performed and the bolusing effect of hospital gowns and blankets were highlighted. The effect of flash for VMAT plans was considered experimentally by using 2 mm couch shifts. Results: For tangents, average skin doses without bolus were 0.64 (EBT3), 0.62 (bare OSLD), 0.77 (jacketed OSLD), and 0.68 (Eclipse) as a fraction of prescription. For VMAT, doses without bolus were 0.53 (EBT3), 0.53 (bare OSLD), 0.64 (jacketed OSLD), and 0.60 (Eclipse). For tangents, the average doses with different boluses as measured by EBT3 were 0.99 (brass mesh), 1.02 (3 mm), 1.03 (5 mm), and 1.07 (10 mm). For VMAT with bolus, average doses as measured by EBT3 were 0.83 (brass), 0.96 (3 mm), 1.03 (5 mm), and 1.04 (10 mm). Eclipse doses agreed with measurements to within 5% of measurements for all Superflab thicknesses and within 15% of measurements for no bolus. The presence of a hospital gown and blanket had a bolusing effect that increased the surface dose by approximately 10%. Conclusions: Results of this work allow for consideration of different bolus thicknesses, materials, and usage schedules based on desired skin dose and choice of either tangents or an arc beam techniques. [ABSTRACT FROM AUTHOR]

Purpose/objective: Quantification of surface dose within the first few hundred water equivalent µm is challenging. Nevertheless, it is of large interest for the proton therapy community to study dose effects in the skin. The experimental determination is affected by the detector properties, such as the detector volume and material. The International Commission on Radiation Units and Measurements in its report 39 recommends assessing the skin dose at a depth of 0.07 mm. The aim of this study is the estimation of the absorbed dose at and around a depth of 70 µm. We used various dosimetric approaches in conjunction with proton pencil beam scanning delivery to determine the skin dose in a clinical setting. Material/methods: Five different detectors were tested for determining the surface dose in water: EBT3 and HD‐V2 GAFCHROMIC™ radiochromic film, LiF:Mg,Ti thermoluminescent dosimeter, IBA PPC05 plane‐parallel ionization chamber, and PTW 23391 extrapolation chamber. The irradiation setup consisted of quasi‐monoenergetic scanned proton pencil beams with kinetic energies of 100, 150, and 226.7 MeV, respectively. Radiochromic films were placed within a vertical stack and in wedge geometry and were analyzed with FilmQA Pro™ adopting triple channel dosimetry. The extrapolation chamber PTW 23391, which served as a reference in the current work, was used in a conventional ionization chamber setup with a fixed electrode gap of 2 mm. Three Kapton® entrance windows with thicknesses of 25, 50, and 75 µm were employed. Thermoluminescent dosimeters were provided as powder and were pressed onto a sheet of aluminum. Furthermore, the Monte Carlo code TOol for PArticle Simulation (TOPAS) in version 3.1.p2 was used to model an IBA pencil beam scanning nozzle and score dose to water in a water phantom. Results: The resulting depth dose curves were normalized to their 100% dose at the reference depth of 3 cm. We obtained the skin doses with the extrapolation chamber and with TOPAS. For the experimental approach this resulted in 79.7 ± 0.3%, 86.0 ± 0.6%, and 87.1 ± 0.1% for the proton energies 100, 150, and 226.7 MeV, respectively. The results for TOPAS were 80.1 ± 0.2% (100 MeV), 87.1 ± 0.5% (150 MeV), and 86.9 ± 0.4% (226.7 MeV), respectively. Based on the experimental results of the skin dose, we provided a clinically relevant surface extrapolation factor for the common measurement methods. This allows the result of the first measurement depth of a detector to be scaled to the dose at the skin depth. Most practical would be the use of the surface extrapolation factor for the PPC05 chamber, due to its direct reading, the wide availability in clinics and the low uncertainties. The calculated factors were 0.986 ± 0.004 for 100 MeV, 0.961 ± 0.008 for 150 MeV, and 0.963 ± 0.003 for 226.7 MeV. Conclusions: In this study, dissimilar experimental approaches were evaluated with respect to measurements at depths close to the surface. The experimental depth dose curves are in good agreement with the simulation with TOPAS Monte Carlo. To the author's knowledge this was the first experimental determination of the skin dose according to the International Commission on Radiation Units and Measurements 39 definition in proton pencil beam scanning. [ABSTRACT FROM AUTHOR]

The biologically relevant depth for acute skin reactions in radiotherapy is 70 µm. The dose at this depth is difficult to measure or calculate and can be quite different than the dose at a depth of as little as 1 mm. For breast radiotherapy with medial and lateral tangential beams, the skin dose depends on both the contribution from the entrance beam and the exit beam. The skin dose has been estimated in a breast model hemi-ellipse accounting for field size, beam energy, obliquity, lack of backscatter, fractionation, size and shape of the hemi-ellipse. The dose has been held constant along the axis of symmetry of the hemi-ellipse by introducing modulation as in clinical IMRT practice. Dose distributions have been computed as a function of the polar angle from the center of the hemi-ellipse. The exit dose always dominates the entrance dose for all realistic parameters. As a result, the surface dose is higher for 18 MV than 6 MV over the entire surface for all reasonable sizes and shapes of the hemi-ellipse. The results of these calculations suggest that substituting an 18 MV beam for a 6 MV beam to achieve greater skin sparing may have just the opposite effect. The ratio of the surface dose to the mid-depth dose ranges from about 35% at polar angle 0o to up to 70% at polar angle 80o. The dose rises sharply at angles above 30o. The surface dose rises moderately at all angles as the size of the hemi-ellipse increases. The effect of shape is somewhat complex: as the breast becomes flatter, doses at intermediate angles increase, but doses at small and large angles decrease. The biologically effective dose for erythema and moist desquamation is about 2 to 3 Gy higher at all polar angles for conventional fractionation (2.00 Gy × 25 fractions) than for hypofractionation (2.66 Gy × 16). [ABSTRACT FROM AUTHOR]

Skin-care cream is commonly applied to relieve skin redness in radiotherapy. However, using cream on the patient under the photon field would increase the skin dose in delivery. The aim of this study is to evaluate the dependences of skin dose enhancement on different beam and cream variables using Monte Carlo simulation. Using a solid water phantom with water-equivalent bolus, PMMA layer and cream layer, we irradiated it by 6 MV photon beams. Skin doses were calculated by varying the beam quality (flattening-filter (FF) and flattening-filter-free (FFF)), beam angle (0°–80°), skin-care cream type (water-based and silicon-based) and cream thickness (0–3 mm) using the EGSnrc Monte Carlo code. The densities of the water- and silicon-based cream were 0.92 and 1.14 g/cm 3. The dose enhancement factor (DEF) defined as the ratio of the skin dose with skin-care cream to the skin dose without cream was calculated. It is found that the FF photon beam had higher DEF value than the FFF. For the water-based cream of 3 mm, the DEF for the FF beam was about 22.1% higher than that of the FFF. While for the silicon-based cream with the same thickness, the DEF was 24.2% higher. DEF value also increased with the beam angle. The DEF values were from 1.4 to 2.52 (water-based cream) and 1.42 to 2.68 (silicon-based cream) when the beam angle was increased from 20° to 80° using the 6 MV FF beams. Similarly, for the 6 MV FFF beams, the DEF values increased from 1.29 to 2.07 and 1.30 to 2.18 for the water- and silicon-based cream. These simulation results showed that the skin dose enhancement increased with an increase of beam angle, cream thickness, cream density, and the irradiation of FFF photon beams. [ABSTRACT FROM AUTHOR]

This study retrospectively analysed the results of using optically stimulated radiation dosimeters (OSLDs) for in vivo dose measurements during total skin electron therapy (TSET, also known as TSEI, TSEB, TSEBT, TSI or TBE) treatments of patients with mycosis fungoides. TSET treatments are generally delivered to standing patients, using treatment plans that are devised using manual dose calculations that require verification via in vivo dosimetry. Despite the increasing use of OSLDs for radiation dosimetry, there is minimal published guidance on the use of OSLDs for TSET verification. This study retrospectively reviewed in vivo dose measurements made during treatments of nine consecutive TSET patients, treated between 2013 and 2018. Landauer nanoDot OSLDs were used to measure the skin dose at reference locations on each patient, as well as at locations of clinical interest such as the head, hands, feet, axilla and groin. 1301 OSLD measurements were aggregated and analysed, producing results that were in broad agreement with previous TLD studies, while providing additional information about the variation of dose across concave surfaces and potentially guiding future refinement of treatment setup. In many cases these in vivo measurements were used to identify deviations from the planned dose in reference locations and to identify anatomical regions where additional shielding or boost treatments were required. OSLDs can be used to obtain measurements of TSET dose that can inform monitor unit adjustments and identify regions of under and over dosage, while potentially informing continuous quality improvement in TSET treatment delivery. [ABSTRACT FROM AUTHOR]

Purpose: The fringe field of the Australian MRI‐linac causes contaminant electrons to be focused along the central axis resulting in a high surface dose. This work aims to characterize this effect using Gafchromic film and high‐resolution detectors, MOSkinTM and microDiamond. The secondary aim is to investigate the influence of the inline magnetic field on the relative dose response of these detectors. Methods: The Australian MRI‐linac has the unique feature that the linac is mounted on rails allowing for measurements to be performed at different magnetic field strengths while maintaining a constant source‐to‐surface distance (SSD). Percentage depth doses (PDD) were collected at SSD 1.82 m in a solid water phantom positioned in a low magnetic field region and then at isocenter of the MRI where the magnetic field is 1 T. Measurements for a range of field sizes were taken with the MOSkinTM, microDiamond, and Gafchromic® EBT3 film. The detectors' relative responses at 1 T were compared to the near 0 T PDD beyond the region of electron contamination, that is, 20 mm depth. The near surface measurements inside the MRI bore were compared among the different detectors. Results: Skin dose in the MRI, as measured with the MOSkinTM, was 104.5% for 2.1 × 1.9 cm2, 185.6% for 6.1 × 5.8 cm2, 369.1% for 11.8 × 11.5 cm2, and 711.1% for 23.5 × 23 cm2. The detector measurements beyond the electron contamination region showed agreement between the relative response at 1 T and near 0 T. Film was in agreement with both detectors in this region further demonstrating their relative response is unaffected by the magnetic field. Conclusions: Experimental characterization of the high electron contamination at the surface was performed for a range of field sizes. The relative response of MOSkinTM and microDiamond detectors, beyond the electron contamination region, were confirmed to be unaffected by the 1‐T inline magnetic field. [ABSTRACT FROM AUTHOR]

The MOSkin, a metal–oxide semiconductor field-effect transistor based detector, is suitable for evaluating skin dose due to its water equivalent depth (WED) of 0.07 mm. This study evaluates doses received by target area and unavoidable normal skin during a the case of skin brachytherapy. The MOSkin was evaluated for its feasibility as detector of choice for in vivo dosimetry during skin brachytherapy. A high-dose rate Cobalt-60 brachytherapy source was administered to the tumour located at the medial aspect of the right arm, complicated with huge lymphedema thus limiting the arm motion. The source was positioned in the middle of patients' right arm with supine, hands down position. A 5 mm lead and 5 mm bolus were sandwiched between the medial aspect of the arm and lateral chest to reduce skin dose to the chest. Two calibrated MOSkin detectors were placed on the target and normal skin area for five treatment sessions for in vivo dose monitoring. The mean dose to the target area ranged between 19.9 and 21.1 Gy and was higher in comparison with the calculated dose due to contribution of backscattered dose from lead. The mean measured dose at normal skin chest area was 1.6 Gy (1.3–1.9 Gy), less than 2 Gy per fraction. Total dose in EQD2 received by chest skin was much lower than the recommended skin tolerance. The MOSkin detector presents a reliable real-time dose measurement. This study has confirmed the applicability of the MOSkin detector in monitoring skin dose during brachytherapy treatment due to its small sensitive volume and WED 0.07 mm. [ABSTRACT FROM AUTHOR]

The 2.5 MV Imaging beam produced by a Varian TrueBeam linear accelerator produces a dose build up effect at the beam entrance similar to other high energy photon beams. The surface dose values were found to range from 39% of maximum dose at a 5 cm × 5 cm field size up to 69% of maximum at a 40 cm × 40 cm field. The depth of maximum dose deposition was found to range from 5 mm at smaller field sizes to 4 mm at larger field sizes. Whilst large absorbed doses will not be delivered utilizing these beams, the data provided will allow the medical physics community to assess and estimate doses to patient's skin and subcutaneous tissue from low energy MV imaging beams. [ABSTRACT FROM AUTHOR]

Cancer is a major health challenge and causes millions of deaths worldwide each year, and the incidence of lung cancer has increased. Augmented fluoroscopic bronchoscopy (AFB) procedures, which combine bronchoscopy and fluoroscopy, are crucial for diagnosing and treating lung cancer. However, fluoroscopy exposes patients and physicians to radiation, and therefore, the procedure requires careful monitoring. The National Council on Radiation Protection and Measurement and the International Commission on Radiological Protection have emphasised the importance of monitoring patient doses and ensuring occupational radiation safety. The present study evaluated radiation doses during AFB procedures, focusing on patient skin doses, the effective dose, and the personal dose equivalent to the eye lens for physicians. Skin doses were measured using thermoluminescent dosimeters. Peak skin doses were observed on the sides of the patients' arms, particularly on the side closest to the x-ray tube. Differences in the procedures and experience of physicians between the two hospitals involved in this study were investigated. AFB procedures were conducted more efficiently at Hospital A than at Hospital B, resulting in lower effective doses. Cone-beam computed tomography (CT) contributes significantly to patient effective doses because it has higher radiographic parameters. Despite their higher radiographic parameters, AFB procedures resulted in smaller skin doses than did image-guided interventional and CT fluoroscopy procedures. The effective doses differed between the two hospitals of this study due to workflow differences, with cone-beam CT playing a dominant role. No significant differences in left and right eye H p (3) values were observed between the hospitals. For both hospitals, the H p (3) values were below the recommended limits, indicating that radiation monitoring may not be required for AFB procedures. This study provides insights into radiation exposure during AFB procedures, concerning radiation dosimetry, and safety for patients and physicians., (© 2024 Society for Radiological Protection. Published on behalf of SRP by IOP Publishing Limited. All rights reserved.)

People who undertaken different X-ray examinations are already exposed to ionizing radiation which causes biological effects. Therefore assessing the patient radiation dose is a prerequisite element in optimizing the X-ray practice and to avoid the unnecessary radiation dose. The aim of this research is to assess the skin radiation dose for those patients who undertaking routine X-ray examinations in selected three hospitals in Al Najaf city. Three X-ray units were involved in this experimental study; these were belonging to three hospitals in Al Najaf city-Iraq, namely Al-Sadder teaching hospital, Al- Hakeem general hospital and Al-Zahraa hospital. Data of exposure parameters (tube potential (kVp), tube current (mAs) and source to detector distance (d cm)). The data were collected from 160 patients exposed to radiation during different X-ray examinations. Patients were chosen to be within adult range (>18 years) and the selection was random (male and female). Patient skin dose was calculated mathematically using an established formula depending on the recorded exposure factor (kVp, mAs and d). Different X-ray examinations were considered, namely skull Posterior –anterior (PA), skull Lateral (LAT), chest PA, chest LAT, abdomen Anterior-posterior (AP), pelvis AP, lumbar spine AP and lumbar LAT. The average skin dose for all X-ray examinations considered in this research were as follow: 0.9, 0.76, 0.23, 0.41, 1.85, 1.82, 2.03 and 3.44 mGy, for skull PA, skull LAT, chest PA, chest LAT, abdomen AP, pelvis AP, lumbar spine(LS) AP and Lumbar spine (LS)LAT respectively. The results demonstrate that the dose values were comparable to those that were previously reported in published reference. [ABSTRACT FROM AUTHOR]

Using in vivo measurements from optically stimulated luminescence dosimeters (OSLDs) to develop and validate a prediction model for estimating the skin dose received by patients undergoing breast intraoperative radiation therapy (IORT). IORT was performed using INTRABEAM-600 with spherical applicators placed in the lumpectomy cavity. Ultrasound skin bridge measurements were used to determine the applicator-to-skin distance, with OSLDs placed to measure the skin surface dose at the corresponding points. The OSLD response was calibrated for the 50 kVp INTRABEAM-600 output. Models were fit to describe the dose fall-off with increasing applicator-to-skin distance and the best fitting model was chosen for estimating skin dose. Twenty four patients with 25 lumpectomy cavities were included, and the average skin dose recorded was 1.18 Gy ± 0.88 Gy, ranging from 0.17 Gy to 4.77 Gy, with an average applicator-to-skin distance of 19.9 mm ± 5.1 mm. An exponential-plateau model was found to best describe the dose fall-off with a root-mean-square error of 0.73. This model was then validated prospectively using skin dose measurements from five consecutive patients. Validation measurements were well within the 95% prediction limits of the model, with a root-mean-square error of 0.52, showing that the prediction model accurately estimates skin dose using ultrasound skin bridge measurements. This prediction model constitutes a useful tool for estimating the skin dose received during breast lumpectomy IORT. The model and accompanying 95% confidence intervals can be used to establish a minimum allowable skin bridge distance, effectively limiting the maximum allowable skin dose. [ABSTRACT FROM AUTHOR]

Background: Effective and skin doses gain much attention since the cardiac catheterization laboratory (CCL) is a place where both patients and medical staff are exposed to X-ray or fluoroscopy environment and gain a cumulative dose during the cardiac interventional procedure.Objective: These doses for pediatric and adult patients undergone cardiac interventional examination using five PMMA phantoms and thermoluminescence dosimeter (TLD)/ionization chamber technique were estimated in this work with the further clinical verification.Methods: Five PMMA phantoms (10, 30, 50, 70, and 90 kg) were customized to represent baby, child, adult female, adult male, and overweight adult (by Asian complexion standards), respectively, in accordance with the ICRU-48 report. Each phantom could be disassembled into 31 plates to insert TLD chips for measuring X-ray exposed dose or assisted with an auxiliary plate to insert high-sensitivity ionization chamber for surveying low-energy fluoroscopy dose.Results: The data acquired from five phantoms were integrated into four semi-empirical formulas, in order to fit the binary quadratic form "Dose = A⋅BMI2+B⋅DAP2+C⋅BMI+ D⋅DAP+E". The latter linked the X-ray and fluoroscopy effective/skin doses, respectively, with a high coefficient of determination R2(from 0.888 to 0.986).Conclusions: The model refinement with DAP share adjustment is envisaged. [ABSTRACT FROM AUTHOR]

Highlights • Dosimetric predictors of skin toxicities after IMRT for HN cancer are lacking. • Data of 70 HN patients (Tomotherapy SIB, 54/66 Gy) were available. • DVHs of skin layers (SL, 2 mm thick) were recovered. • SL DVHs (V53Gy-V68Gy) predict CTCAEv4.0 G2/G3 acute toxicity. • Constraining V64 < 3 cc, should keep the risk of G3 toxicities below 10%. Abstract Purpose To explore the association between planning skin dose-volume data and acute cutaneous toxicity after Radio–chemotherapy for Head and Neck (HN) cancer patients. Methods Seventy HN patients were treated with Helical Tomotherapy (HT) with radical intent (SIB technique: 54/66 Gy to PTV1/PTV2 in 30fr) ± chemotherapy superficial body layer 2 mm thick (SL2) was delineated on planning CT. CTCAE v4.0 acute skin toxicity data were available. Absolute average Dose-Volume Histograms (DVH) of SL2 were calculated for patients with severe (G3) and severe/moderate (G3/G2) skin acute toxicities. Differences against patients with none/mild toxicity (G0/G1) were analyzed to define the most discriminative regions of SL2 DVH; univariable and multivariable logistic analyses were performed on DVH values, CTV volume, age, sex, chemotherapy. Results Sixty-one % of patients experienced G2/G3 toxicity (rate of G3 = 19%). Differences in skin DVHs were significant in the range 53-68Gy (p-values: 0.005–0.01). V56/V64 were the most predictive parameters for G2/G3 (OR = 1.12, 95%CI = 1.03–1.21, p = 0.001) and G3 (OR = 1.13, 95%CI = 1.01–1.26, p = 0.027) with best cut-off of 7.7cc and 2.7cc respectively. The logistic model for V56 was well calibrated being both, slope and R2, close to 1. Average V64 were 2.2cc and 6cc for the two groups (G3 vs G0-G2 toxicity); the logistic model for V64 was quite well calibrated, with a slope close to 1 and R2 equal to 0.60. Conclusion SL2 DVH is associated with the risk of acute skin toxicity. Constraining V64 < 3cc (equivalent to a 4x4cm2 skin surface) should keep the risk of G3 toxicity below or around 10%. [ABSTRACT FROM AUTHOR]

In a previous study, we reported on a novel (prototype) real-time patient dosimeter with non-toxic phosphor sensors. In this study, we developed new types of sensors that were smaller than in the previous prototype, and clarified the clinical feasibility of our newly proposed dosimeter. Patient dose measurements obtained with the newly proposed real-time dosimeter were compared with measurements obtained using a calibrated radiophotoluminescence glass reference dosimeter (RPLD). The reference dosimeters were set at almost the same positions as the new real-time dosimeter sensors. We found excellent correlations between the reference RPLD measurements and those obtained using our new real-time dosimeter (r 2 = 0.967). However, the new type of dosimeter was found to underestimate radiation skin dose measurements when compared with an RPLD. The most probable reason for this was the size reduction in the phosphor sensor of the new type of dosimeter. We believe that, as a result of reducing the phosphor sensor size, the backscattered X-ray irradiation was underestimated. However, the new dosimeter can accurately determine the absorbed dose by correcting the measured value with calibration factors. The calibration factor for the new type dosimeter was determined (by linear regression) to be ~1.15. New real-time patient dosimeter design would be an effective tool for the real-time measurement of patient skin doses during interventional radiology treatments. [ABSTRACT FROM AUTHOR]

In‐phantom and in‐vivo three dimensional conformal radiation therapy (3DCRT) and volumetric modulated arc therapy (VMAT) skin doses, measured with and without bolus in a female anthropomorphic phantom RANDO and in patients, were compared against treatment planning system calculated values. A thorough characterization of the metal oxide semiconductor field effect transistor measurement system was performed prior to the measurements in phantoms and patients. Patients with clinical indication for postoperative external radiotherapy were selected. Skin dose showed higher values with 3DCRT technique compared with VMAT. The increase in skin dose due to the use of bolus was quantified. It was observed that, in the case of VMAT, the bolus effect on the skin dose was considerable when compared with 3DCRT. From the point of view of treatment time, bolus cost, and positioning reproducibility, the use of bolus in these situations can be optimized. [ABSTRACT FROM AUTHOR]

Use of diagnostic reference levels (DRLs) is an important tool for patient dose optimization in interventional radiology. DRLs are normally expressed in terms of kerma-area product (Pka). However, no direct method is available to estimate the probability of skin reactions using system displayed quantities. The aim of this work was to measure skin entrance doses (SEDs) in patients undergoing coronary angiography (CA) and percutaneous coronary interventions (PCI) using Gafchromic films and establish DRLs. The details of patients, exposure parameters, and dose quantities were recorded for 572 patients. Out of these, skin doses were measured for selected 64 patients using Gafchromic film. Measured SEDs are in the range of 48.2–740 mGy and 84–1242 mGy for CA and PCI, respectively. The data of 572 patients were analyzed, and 75th percentile of Pkawas calculated. DRLs for CA and PCI in terms of Pkaare found to be 34 and 134 Gy.cm2, respectively. DRLs for CA and PCI in terms of cumulative air kerma (Ka) at reference point are found to be 590 mGy and 1930 mGy, respectively. SED has a good correlation with Ka, however, it does not correlate well with Pka. [ABSTRACT FROM AUTHOR]

Abstract Interventional cardiologists (ICs) receive the largest radiation dose of any medical specialist working with X-ray techniques. The aim of present study has been to obtain dose estimates received by ICs during fluoroscopically-guided imaging and interventional procedures. TLDs in the form of badges, rings, and chips have been used, measuring H p (10) and H p (0.07) as appropriate. During the course of 41 coronary angiography (CAG) cases, 50 percutaneous coronary intervention (PCI) cases and 9 (CAG + PCI) procedures, cardiologist doses to the skin of the hands, upper neck area and to the eyes were assessed. Two-TLD badges were placed at the level of the Pb-composite collar exterior to the shielding, with a further two placed under and two more over the Pb-composite apron. Four chip-form TLDs were positioned above the eyebrows (two for the right- and two for the left eye), and two ring dosimeters were worn on the left and right hands. Cardiologist doses correlated with total fluoroscopy time over the five month period of the survey, the annual effective doses received by the body, eyes, hands and upper trunk area being estimated to be 8.0-, 10.7-, 24.3- and 10.2 mSv respectively, all well below the ICRP recommended equivalent dose limits, indicating well-controlled radiation protection practices. Highlights • The present study estimates received by ICs during fluoroscopically-guided imaging. • TLDs in the form of badges, rings, and chips have been used. • The annual effective doses to the body, eyes, hands and upper trunk area was estimated. • Occupational doses were all well below the ICRP recommended equivalent dose limits. • TLDs measuring H p (10) & H p (0.07) were used. [ABSTRACT FROM AUTHOR]

Aim of the study: Accurate skin dose assessment is necessary during breast radiotherapy to assure that the skin dose is below the tolerance level and is sufficient to prevent tumour recurrence. The aim of the current study is to measure the skin dose and to evaluate the geometrical/anatomical parameters that affect it. Material and methods : Forty patients were simulated by TIGRT treatment planning system and treated with two tangential fields of 6 MV photon beam. Wedge filters were used to homogenise dose distribution for 11 patients. Skin dose was measured by thermoluminescent dosimeters (TLD-100) and the effects of beam incident angle, thickness of irradiated region, and beam entry separation on the skin dose were analysed. Results : Average skin dose in treatment course of 50 Gy to the clinical target volume (CTV) was 36.65 Gy. The corresponding dose values for patients who were treated with and without wedge filter were 35.65 and 37.20 Gy, respectively. It was determined that the beam angle affected the average skin dose while the thickness of the irradiated region and the beam entry separation did not affect dose. Since the skin dose measured in this study was lower than the amount required to prevent tumour recurrence, application of bolus material in part of the treatment course is suggested for post-mastectomy advanced breast radiotherapy. It is more important when wedge filters are applied to homogenize dose distribution.

PurposeA recent randomized phase III clinical trial in patients with glioblastoma demonstrated the efficacy of tumor treating fields (TTFields), in which alternating electric fields are applied via transducer arrays to a patient’s scalp. This treatment, when added to standard of care therapy, was shown to increase overall survival from 16 to 20.9 months. These results have generated significant interest in incorporating the use of TTFields during postoperative concurrent chemoradiation. However, the dosimetric impact of high-density electrodes on the scalp, within the radiation field, is unknown.MethodsThe dosimetric impact of TTFields electrodes in the radiation field was quantified in two ways: (1) dose calculated in a treatment planning system and (2) physical measurements of surface and deep doses. In the dose calculation comparison, a volumetric-modulated-arc-therapy (VMAT) radiation plan was developed on a CT scan without electrodes and then recalculated with electrodes. For physical measurements, the surface dose underneath TTFields electrodes were measured using a parallel plate ionization chamber and compared to measurements without electrodes for various incident beam angles and for 12 VMAT arc deliveries. Deep dose measurements were conducted for five VMAT plans using Scandidos Delta4 diode array: measured doses on two orthogonal diode arrays were compared.ResultsIn the treatment planning system, the presence of the TTFields device caused mean reduction of PTV dose of 0.5–1%, and a mean increase in scalp dose of 0.5–1 Gy. Physical measurement showed increases of surface dose directly underneath by 30–110% for open fields with varying beam angles and by 70–160% for VMAT deliveries. Deep dose measurement by diode array showed dose decrease of 1–2% in most areas shadowed by the electrodes (max decrease 2.54%).ConclusionThe skin dose in patients being treating with cranial irradiation for glioblastoma may increase substantially (130–260%) with the addition of concurrent TTFields electrodes on the scalp. However, the impact of dose attenuation by the electrodes on deep dose during VMAT treatment is of much smaller, but measureable, magnitude (1–2%). Clinical trials exploring concurrent TTFields with cranial irradiation for glioblastoma may utilize scalp-sparing techniques to mitigate any potential increase in skin toxicity.

Dental panoramic radiograph in Indonesia has been widely used. Modern diagnostic imaging equipment with minimum radiation is still very limited. One of the conditions in nuclear safety law, UU 10/1997, is an optimization of all radiation sources with DRL through skin dose measurements. In Indonesia, the national DRL has not been established yet, and there were no reports on the study of panoramic skin dose in Indonesia. The aim of this preliminary study was to obtain a panoramic skin dose radiation as reference to establish DRL in Indonesia. Panoramic radiographs of sixteen female and fifteen male patients, aged 4 – 48 years, were taken using the standard conventional method, with TLD chips attached in location groups. The chips were then read with the detector and integrator of BATAN, in high and low temperature condition at the same time. It was revealed that behind the right and left ear were the regions with the highest radiation dose received, followed by the back of the neck, left jaw, right jaw, and chin. The result of this study has shown the importance of DRL in Indonesia since the use of modern diagnostic imaging equipement that limits radiation dose to the minimum level is still very limited.

The manipulation of radiopharmaceuticals in nuclear medicine can result in the droplet contamination of operators resulting in the accumulation of a significant skin dose. Current methods to estimate this skin dose often utilise a 50 μ l cylindrical droplet model, which can lead to unrealistically high estimated skin doses for some radiopharmaceuticals. By conducting experiments to measure the volume of real droplets arising from simulating the manipulation of radiopharmaceuticals, this work found that 50 μ l is an overestimation of a realistic contamination droplet. For almost all radiopharmaceuticals considered in this work, incorporating a smaller droplet volume into skin dose simulations resulted in higher estimates of skin dose rate per unit of activity, which, when combined with appropriate activity concentrations and droplet volumes, resulted in lower skin doses for contamination droplet incidents. The results presented in this work challenge the 50 μ l contamination droplet volume and highlight the importance of having an accurate model when estimating the skin dose for contamination scenarios., (© 2023 King’s College Hospital NHS Foundation Trust. Published by IOP Publishing Ltd.)