Out-of-field surface dose readings during panoramic radiography: Comparison of standard and manufacturer low-exposure protocols in an anthropomorphic phantom.

Accurate estimation of entrance skin dose (ESD) is essential for radiation protection and protocol optimization. This study proposes a new analytical formulation for ESD estimation, the New Mathematical Model Equation for ESD (NMMEESD), which explicitly integrates both technical and geometric beam-formation parameters, notably the ripple factor and anode angle. These parmeters are often neglected in conventional ESD models. A dataset comprising 3800 examinations acquired from four high-frequency X-ray generators was analyzed. NMMEESD predictions were compared with experimental measurements, Monte Carlo simulations using PHITS, and the Davies and Edmonds models. The ripple factor and anode angle influence on ESD was evaluated using sensitivity analysis based on Friedman tests and Wilcoxon signed-rank post-hoc comparisons. NMMEESD predictions showed strong agreement with both experimental measurements and PHITS simulations (with deviations of ≤ 8.6%, r = 0.996, p > 0.05). Compared with conventional formulations, the proposed model demonstrated comparable predictive performance to the Davies model while offering improved robustness under practical clinical conditions and reduced discrepancies compared with the Edmonds model (up to 59.6%, p < 0.01). Sensitivity analysis indicated statistically significant ESD variations associated with ripple factor and anode angle (p < 0.001). Furthermore, the NMMEESD analytical model provided instantaneous dose estimates. The NMMEESD model provides a reliable, non-invasive analytical approach for ESD estimation. Explicit inclusion of ripple factor and anode angle in the proposed formulation improves predictive dose estimation accuracy under realistic operating conditions, offering measurable practical benefit for routine clinical dosimetry.

A Systematic Review and Meta-Analysis of Peak Skin Dose Determination Methods during Standard and Complex Endovascular Aortic Aneurysm Repair Procedures.

Objective.Accurate target localization in frameless stereotactic radiosurgery (SRS) is commonly achieved using intrafraction kV x-ray imaging, which contributes to patient imaging dose. In this study, the feasibility of reducing the imaging dose in CyberKnifeTMSRS by implementing copper (Cu) beam-hardening filtration while preserving image-guided targeting accuracy is investigated.Approach.Entrance skin dose (ESD) at isocenter was measured for standard aluminum (Al) filtration and additional Cu filtration thicknesses of 0.12 mm and 0.24 mm. Monte Carlo simulations were used to characterize Cu-induced x-ray spectral changes and to estimate imaging doses using patient-specific voxelized anatomical models over a range of tube potentials and filtration conditions. The effect of Cu filtration on targeting accuracy was assessed using end-to-end (E2E) tests, supplemented by patient image data.Main results.Copper filtration progressively removed low-energy photons, increasing the mean photon energy from 56 keV with standard Al filtration to 60 keV and 64 keV for 0.1 mm and 0.2 mm Cu filtration at 120 kVp. At 10 mAs, ESD increased from 0.248 mGy at 80 kVp to 0.822 mGy at 150 kVp with Al filtration, while addition of 0.12 mm and 0.24 mm Cu reduced ESD by 46% and 64% at 80 kVp and by 25% and 36% at 150 kVp, respectively. Patient model calculations confirmed meaningful organ dose sparing for the eye lenses, thyroid gland, and skin. For 6Dskull tracking, implementation of Cu filters induced modest image brightness/gradient error changes which were readily compensated by small kVp increase without mAs adjustment. For Xsight spine and fiducial tracking algorithms registration performance was maintained with the addition of Cu filtration. E2E testing confirmed that the total system targeting error was maintained for all three tracking algorithms studied.Significance.Copper filtered imaging constitutes an effective strategy for optimizing imaging dose in the evaluated CyberKnife tracking workflows without compromising tracking accuracy.

Objective.Accurate surface dosimetry is recommended for detecting treatment error and managing skin toxicity. However, measurements using detectors such as optically stimulated luminescence dosimeters (OSLDs) may overestimate surface dose in the buildup region due to detector thickness. We developed a new automated framework to overcome these challenges and enhance dose correction accuracy.Approach.The proposed framework includes: (i) determining the detector's position and orientation on the patient's curved surface; (ii) calculating the beam incidence angle for each detector across all radiation beams using treatment planning data and the orientation of the detector; (iii) assessing detector placement relative to the radiation field, and the alignment within irregular subfield areas; (iv) computing the cumulative field contributions to the detector response across all fields; and (v) applying the detector correction factor, defined as the ratio of surface film measurements to detector readings, while considering beam incidence angle and field size. To demonstrate the proof-of-concept of the developed framework, it was evaluated across four treatment modalities using two OSLD types, nanoDot and myOSLchip. Performance was assessed by comparing the OSLD-measured surface dose with the framework-corrected surface dose.Main results.The framework effectively corrected OSLD response to reference skin dose, thereby enhancing the accuracy of skin dose estimation. In the anthropomorphic phantom study, the deviation of OSLD response from skin dose varied up to 21.48% for nanoDot and 46.63% for myOSLchip. With the proposed framework, the deviation was reduced to within 5% across all treatment modalities for both OSLD types, demonstrating a substantial improvement in measurement accuracy.Significance.This novel framework automates the correction of complex factors affecting surface dosimetry, mitigating measurement variability and improving accuracy and consistency. Its feasibility was demonstrated in a phantom-based, preclinical evaluation using breast radiotherapy treatment plans.

Post-mastectomy radiotherapy (PMRT) improves both the locoregional control and survival in advanced breast cancer. While the use of bolus can enhance skin dose, many oncologists prefer not to use it because of the dramatic increase in skin toxicity. The optimal technique to ensure adequate skin dose is unknown, and this study compares the superficial dose for three techniques - field-in-field intensity modulated radiotherapy (FIF-IMRT), volumetric-modulated arc therapy (VMAT), and flattening-filter-free volumetric-modulated arc therapy (FFF-VMAT) - in patients receiving only PMRT without bolus. CT simulation data of 51 post-mastectomy patients treated between 2023 and 2024 were acquired. For each patient, three plans (FIF-IMRT, VMAT, FFF-VMAT) were generated using 6 MV beams with the Anisotropic Analytical Algorithm (AAA) for dose calculation. The skin target volume was defined as a 2 to 5mm subcutaneous layer. Dosimetric endpoints included skin V90%, mean dose, Dmin1cc, and PTV_eval V90% and V105%. Statistical analysis used was the Friedman test with significance set at p<0.001. 153 plans were generated. FIF-IMRT systematically demonstrated superior skin coverage: median skin V90% was 81.6% vs. 61.5% (FFF-VMAT) and 57.0% (VMAT); median mean skin dose was 94.6% (FIF-IMRT) vs. 90.7% (FFF-VMAT) and 90.1% (VMAT). Dmin1cc was also the highest with FIF-IMRT. Differences were all statistically significant (p<0.001). The PTV_eval dose was more homogeneous with VMAT and FFF-VMAT, and a 2.1% increase of V105% with FIF-IMRT was deemed clinically acceptable. In the absence of a bolus, FIF-IMRT systematically provides superior and consistent coverage of the superficial dermis compared to VMAT-based techniques.

Comparative Analysis of Acute Skin Reactions after Postmastectomy Photon and Intensity Modulated Proton Therapy.

High-energy photon beams are widely used in radiotherapy owing to their effectiveness in treating deep-seated tumors and their skin-sparing effects. However, treatment planning systems — the most common method for estimating skin dose — have been reported to deviate by as much as 34% from measurements, potentially leading to various side effects. To address this issue, numerous studies have explored skin dosimeters for direct skin dose measurement. However, many of these are limited in clinical applicability because they rely on highly toxic materials such as lead and mercury. In this study, a skin dosimeter based on BaTiO3 — a nearly non-toxic material — was fabricated, and its fundamental response to high-energy photon beams was evaluated to assess its feasibility for practical applications. The dosimeter was tested for linearity, repeatability, dose-rate dependence, and percent-depth-dose (PDD) conformity. The results demonstrated excellent linearity and repeatability, along with consistent performance across varying dose rates. However, although the dosimeter exhibited excellent D max conformity, the PDD20/10 values exhibited errors greater than 3.4%, which are likely attributed to several factors, including the atomic number and energy dependence of the sensor. These findings suggest that BaTiO3 possesses favorable electrical characteristics for use as a skin dosimeter and that a clinically viable device may be achievable through further studies.

Hand-foot syndrome (HFS) is a common side effect of chemotherapy drugs such as 5-fluorouracil and capecitabine, impairing daily function and quality of life. This study aimed to compare international clinical guidelines regarding assessment and management of HFS to identify areas of consensus and divergence and evidence gaps. Guidelines were identified through PubMed (from inception to February 2025), with a supplementary search on Google. Only the most recent versions of English guidelines were included. Data extraction focused on the guideline methodology and recommendations on the prevention, assessment, and management of HFS. Each guideline was critically appraised using the AGREE II checklist. Six guidelines were identified authored by the following cancer agencies: British Columbia Cancer (BCC), European Society of Medical Oncology (ESMO), Cancer Institute NSW (eviQ), Oncology Nursing Society (ONS), United Kingdom Oncology Nursing Society and Acute Oncology (UKONS AO), and United Kingdom North Cancer Alliance (UKNCA). Regarding prevention, five of six guidelines (83%) advised avoiding chemical and physical stressors to the hands and feet and using alcohol-free moisturizer. Only ESMO, BCC, and eviQ recommended oral celecoxib to prevent capecitabine-induced HFS. ESMO and ONS recommended cooling procedures to prevent taxane-induced HFS. Likewise, BCC and eviQ recommend cooling procedures for all agents. All guidelines except ONS recommended dose suspension with grade 2 or 3 HFS and continuation when resolved or improved. ESMO and BCC recommended topical corticosteroids for grade 1 HFS, ESMO for grade 2 or 3, and eviQ for prophylactic use. Finally, BCC and ESMO suggested to consider oral dexamethasone for PEGylated doxorubicin-induced HFS. While general skin care and dose modification guideline recommendations were consistent, pharmacological recommendations varied. Guidelines are key for healthcare professionals in supporting patients with HFS. Therefore, regular updates with emerging evidence for interventions such as topical diclofenac are needed to ensure the quality of care.

Objective.Contemporary particle accelerators allow for the generation of a narrow pencil beam of electrons which can be scanned to deliver a clinical dose distribution at an ultra-high (FLASH) dose rate. This study develops a radiotherapy beam model and discrete ordinates Boltzmann solver for such an accelerator and then applies the method to treatment planning for superficial brain metastases.Approach.Beam profiles for the quasi-monoenergetic 17.5 MeV electron beam from the Photo Injector Test facility at Deutsches Elektronen-Synchrotron laboratory in Zeuthen (PITZ) were measured at various depths in a water tank using radiochromic film. The incident radiation was modelled as a Gaussian source and the electron distribution in the patient was modelled using classical observations with continuous slowing down approximation (CSDA). This distribution then formed the fixed source component in a discrete ordinates Boltzmann solver. The dose calculation method was then applied to a retrospective study of six patients with superficial brain metastases. The dose due to scanned electrons was compared with that from a single passively scattered proton beam at ultra-high dose rate (UHDR), a proton arc, and a robotic photon treatment.Main results.The calculated dose distribution in a homogeneous water phantom agreed with the measured data to within the 3% experimental uncertainty at all depths. Scanned electron beams were able to provide dose distributions for superficial brain metastases that had a better conformity index than either passively scattered protons or robotic photon treatment (1.02 ± 0.13 versus 1.54 ± 0.13 and 1.35 ± 0.26 respectively; median ± hemi-range; p < 0.05). Brain V12Gyand skin dose were acceptable for all treatments.Significance.The dose calculation provides a fast and efficient method for inverse planning in the potential clinical application of a scanned electron beam at UHDR. The results show that such an approach could be useful in the treatment of superficial target volumes.

With expanding indications for interventional neuroradiology, patient radiation exposure remains a significant concern. This study aimed to identify predictors of high peak skin dose and left lens doses using directly measured patient radiation data. We retrospectively analyzed patient doses and performed multivariate logistic regression. Treatment of a posterior circulation aneurysm [odds ratio (OR)=7.491; 95% confidence interval (CI), 1.217-46.110] and stent use (OR=5.516; 95% CI, 1.318-23.085) were identified as independent predictors of peak skin dose exceeding 1.0Gy. Stent use was also a significant predictor of left lens dose exceeding 100mGy (OR=3.141; 95% CI, 1.488-7.851). These findings provide a robust, evidence-based framework for identifying high-risk patients preprocedurally. This knowledge is crucial for enhancing the informed consent process and justifying the timely implementation of dose-reduction strategies to minimize the risk of radiation-induced injuries.

Chest radiography is essential in neonatal intensive care units (NICUs), but repeated exposures raise concerns due to the high radiosensitivity of newborns. This study aimed to estimate entrance skin dose (ESD) and absorbed organ doses in neonates undergoing chest X-ray examinations, under varying exposure parameters, using Monte Carlo simulation. A realistic NICU scenario was modeled in MCNP6.3 Monte Carlo code, including a mobile X-ray unit, an incubator, and ICRP 143 neonatal reference phantoms. Simulations were performed for tube voltages ranging from 45 to 65 kV and radiation field sizes of 10 × 10 , 15 × 15, and 20 × 20 cm 2 . Experimental validation was carried out using a water phantom and a solid-state dosimeter. ESD ranged from 15.36 to 59.81 μ Gy, with a mean of 36.45 μ Gy. Absorbed organ doses varied widely: brain (0.14–1.31 μ Gy), lens (0.13–1.33 μ Gy), esophagus (6.46–52.51 μ Gy), stomach (25.50–118.40 μ Gy), liver (13.98–78.64 μ Gy), red bone marrow (0.71–10.50 μ Gy), kidneys (2.89–25.23 μ Gy), thyroid (1.82–29.59 μ Gy), and lungs (4.88–39.46 μ Gy). Dose increases were driven primarily by higher tube voltages and, most significantly, by the inclusion of the organ within the primary beam. These findings highlight the importance of strict collimation and optimized parameters in neonatal radiography, reinforcing the ALARA principle. • Organ doses were determined using MCNP6.3 and ICRP 143 neonatal phantoms. • We modeled a complete NICU scenario, with incubator and mobile X-ray unit. • Stomach received the highest mean absorbed dose (54.44 μ Gy). • Organ doses peaked in liver and stomach. • Field size of 20 × 20 cm 2 raised liver dose by over 5-fold.

The absorbed dose in Boron Neutron Capture Therapy (BNCT) arises from various radiation components, each contributing differently to the overall biological effect. These effects depend not only on the absorbed dose but also on the type and energy of the involved secondary charged particles. Current dosimetric models convert absorbed dose into an equivalent photon dose using radiation-specific weighting factors that account for some differences in radiation type. However, these models generally neglect the energy dependence of biologicaleffectiveness. To evaluate the relevance of incorporating the energy dependence of secondary charged particles into BNCT dosimetry, and to assess its impact on dose calculations and clinical outcomeestimations. The photon isoeffective dose formalism was extended by reformulating the mathematical model for in terms of the secondary particle fields rather than dose components in BNCT. Tissue-specific radiobiological (RB) parameters and were introduced as functions of Linear Energy Transfer (LET), as predicted by the BIANCA biophysical model for normal skin and head and neck tumor tissues. Recoil proton spectra were analyzed at superficial and deep locations in tissues to evaluate their effectiveness relative to 583keV protons from the (n,p) reaction. Four approaches to , with varying levels of detail regarding energy and radiation fields representation, were evaluated across three scenarios. The analysis moved from a simplified geometry using a cylindrical phantom irradiated with epithermal neutrons, to progressively more realistic clinical scenarios, including a head and neck cancer treatment planning case and a retrospective study of a cutaneous melanoma case treated with BNCT at the RA-6 reactor inArgentina. Recoil protons were found to have lower than 583keV protons from (n,p) reactions, indicating that assuming equal effectiveness leads to overestimated doses in photon-equivalent units. In the phantom, detailed LET-based modeling proved essential in low-to-moderate boron concentration or superficial tissue scenarios, where simplified models showed deviations up to 30%. In contrast, boron-rich or deep tissue conditions tolerated simplifications with minimal loss of accuracy. In the head and neck case, simplified models led to skin overdoses up to 13%, increasing NTCP from negligible ( ) to high values ( ), thus raising the potential radiotoxicity risk. An apparent gain in TCP resulted from overestimating the required treatment time due to oversimplified modeling. In the retrospective melanoma case irradiated with the RA-6 mixed thermal-epithermal beam, simplified models underestimated the skin dose by 8% to 12%, potentially compromising dose-responseinterpretations. Beyond treatment planning, accurate dose modeling is also key for outcome assessment and meaningful comparisons with photon radiotherapy. Incorporating detailed LET-dependent RB modeling is especially important in scenarios involving low-to-moderate boron concentration levels or superficial tissues, where recoil protons dominate the dose composition. In contrast, simplified models may be acceptable in boron-rich, high-LET contexts, particularly when constrained by limited radiobiological data or computational resources. These findings support the development of a flexible photon isoeffective dose formalism that can evolve alongside advances in BNCT technologies and RBdata.

Approximately one-third of US adults have tattoos, yet the dosimetric impact of intradermal tattoo pigments during radiation therapy remains uncharacterized. Commercial tattoo inks contain unregulated metallic impurities including chromium, lead, and nickel, raising concerns about dose perturbations in tattooed skin. This work quantifies radiation dose perturbations induced by high-atomic-number (Z) tattoo pigments under clinically relevant radiotherapy conditions. Monte Carlo simulations (TOPAS) modeled layered skin phantoms with a 0.3-mm intradermal tattoo layer embedded at 1.25–1.55 mm depth. Three commercial inks were evaluated: carbon-based (black) and metal-containing (Fe-rich brown, Al-containing orange) at pigment loadings of 5–100 vol% within the tattoo layer, to establish upper-bound effects. Electron (6, 18 MeV) and photon (6, 18 MV) beams were simulated with standard clinical geometry (1 × 1 cm² field, SSD = 100 cm). Photon irradiation produced pronounced, depth-localized dose enhancement, with peak dose enhancement factor (DEF) reaching 2.5 for brown ink at 18 MV, a 62% mean increase relative to non-tattooed skin driven by high-Z–mediated secondary electron production. Electron beams exhibited energy-dependent behavior: 6 MeV produced modest enhancement (peak DEF ~ 1.07), while 18 MeV unexpectedly generated dose deficits (DEF < 1.0) due to enhanced lateral scattering. Critically, all perturbations remained depth-confined without lateral propagation, preserving spatial dose uniformity across tattooed and non-tattooed regions. Tattoo pigments containing toxic metals create substantial localized dose enhancements under photon irradiation but minimal perturbations under electron therapy. These modality-dependent effects represent a previously unrecognized source of dose uncertainty in radiotherapy and warrant consideration in treatment planning for the growing population of tattooed patients.

Radiation Exposure during Recanalisation of Chronic Unilateral Iliofemoral Venous Obstruction Based on Anatomical Classification.

Gold nanoparticle (GNP) enhanced radiosensitization was studied across three tumour cells lines that vary in radiosensitivity for a 2.5 MV photon beam. The intrinsic sensitivity of the cell lines is studied for the effects of GNPs. Three cell lines which exhibit differences in radiation response: prostate adenocarcinoma (PC-3), breast adenocarcinoma (MDA-MB-231), and cervical adenocarcinoma (HeLa) were used to determine thein vitrodose enhancement effects of GNPs combined with a 2.5 MV photon beam. Cells were incubated with 20 μg ml-1GNPs for 24 h, and any extracellular GNPs were washed out prior to each assay. The cellular uptake of GNPs was assessed with inductively coupled plasma optical emission spectroscopy (ICP-OES). Clonogenic assays were conducted to assess cell viability after irradiation. The biological damage was assessed through DNA damage using terminal deoxynucleotidyl transferase dUTP nick end labeling assay (TUNEL). The production of reactive oxygen species (ROS) was assessed using CellRox assays. The enhancement factor when cells were irradiated in the presence of GNPs with 2.5 MV was 1.35±0.46 for HeLa, 1.35±0.11 for MDA-MB-231, and 0.99±0.08 for PC-3 cells. On average, the level of DNA damage increased in MDA-MB-231 and HeLa cells when irradiated with 2.5 MV in the presence of GNPs. Increase in the ROS levels were detected in all cell lines when irradiated in the presence of GNPs. The enhancement effects with GNPs combined with a 2.5 MV photon beam were dependent on the cell line. The enhancement factor for HeLa and MDA-MB-231 supports further investigation of intermediate photon-energy beams in combination with GNPs. The combination of using a conventionally lower energy megavoltage beam with gold nanoparticles may become applicable in the clinical setting due to reduced skin dose and enhanced secondary electron production.

To gauge the views of UK nuclear medicine staff on a skin contamination incident of 500 mSv from Tc-99m and Ra-223 (an alpha source). An anonymous questionnaire asked staff their concerns on anxiety, erythema, and skin cancer. Also, aspects of removal from open-source work. The same question set was used for Tc-99m and Ra-223. Replies were grouped as 37 RPAs, 121 other physicists, 78 technologists/radiographers, and 31 radiopharmacy staff. Scores encompassed 1-10 for all staff groups for questions on 'anxiety', 'erythema', and 'skin cancer'. However all staff groups scored significantly higher for Ra-223 than for Tc-99m. The majority of staff in all groups expected to be removed from open-source work, with timescales up to a year. Many staff indicated they would prefer not to be taken out of work (56% for a Tc-99m incident and 47% for a Ra-223 incident). But, a high proportion of staff wanted to have significant time off (≥3 months). In practice, there is no risk of erythema and the skin cancer risk is extremely low. This applies to Tc-99m and to Ra-223. Also, the IRR2017 allow for someone who receives an overexposure to continue to work, with modified dose limits and agreement from the appointed doctor. All staff groups need to have a clearer understanding of the risks and implications of receiving this level of skin dose. The high anxiety levels indicate that return to work needs careful communication that it is because of low risks and within the legal framework.

Recent Boron neutron capture therapy (BNCT) has shifted to accelerator-based systems. One of them is a compact neutron generator developed using silicon carbide (SiC) semiconductors by Fukushima SiC Applied Technology Co. However, neutron penetration remains a critical challenge for treating deep-seated tumors. This study investigated the potential of neutron sieve therapy, originally developed to enhance the depth dose distribution in X-ray therapy, to improve BNCT dose distribution via Monte Carlo simulations based on the Fukushima SiC BNCT system. Dose distribution changes were investigated using polyethylene and 6LiF-plastic in block and sieve shapes. The results show that the maximum thermal neutron fluence depth was shallower (deeper) with polyethylene (6LiF-plastic) filters. The sieve filter moderately altered the dose distribution compared to the block filter due to density differences. The maximum dose point shifted 8mm deeper using a sieve filter composed of 6LiF-plastic and polyethylene, with a 5.5% increase at 20mm depth in neutron fluence at the same skin dose.

PurposeEarly-stage non-melanoma skin cancer (NMSC) is usually treated with surgical excision with or without adjuvant radiotherapy. Tumor location on facial sub-sites may lead to poor cosmetic outcomes with surgery. Surface mould brachytherapy offers better conformality, reduced treatment duration, and comparable local control and cosmetic outcomes.Material and methodsTwenty-eight patients with NMSC of the face or scalp received definitive or adjuvant radiotherapy using a customized surface mould brachytherapy technique. Prescription dose was 3,500-4,200 cGy in 9-12 fractions. Clinical target volume (CTV) V100, V150, 0.1 cc, 1 cc, and 2 cc skin doses, and mould parameters were recorded from planning system. Toxicity and cosmetic outcomes were compared with dosimetry and mould parameters using independent sample t-test. Binary mould parameters were compared with toxicity profile using chi-square or Fisher’s exact tests.ResultsThirteen (46.4%), six (21.4%), and eight (28.6%) patients experienced grade 2 acute skin, late skin, and late subcutaneous toxicity, respectively. Among grade 3 toxicity, only 1 acute skin toxicity was observed. All patients had either excellent or good cosmetic outcomes, while 0.1 cc, 1 cc, 2 cc skin dose, and homogeneity index were significant predictors of late skin, subcutaneous toxicity, and cosmetic outcome. For cosmesis, the distance from catheter midpoint to skin surface was also a significant predictor of outcome. After a median follow-up of 54 months, no disease recurrence was observed in the study cohort.ConclusionsSurface mould brachytherapy can provide excellent local control and cosmetic outcome for the treatment of NMSC.

The prospective phase I "Flash-Skin I" trial: ultra-high dose rate radiotherapy implementation and quality assurance at a clinical linear accelerator.