Dose Distribution For Treatment Research Articles

Radiation Dose-Volume-Response Relationships for Adverse Events in Childhood Cancer Survivors: Introduction to the Scientific Issues in PENTEC

At its very core, radiation oncology involves a trade-off between the benefits and risks of exposing tumors and normal tissue to relatively high doses of ionizing radiation. This trade-off is particularly critical in childhood cancer survivors (CCS), in whom both benefits and risks can be hugely consequential due to the long life expectancy if the primary cancer is controlled. Estimating the normal tissue-related risks of a specific radiation therapy plan in an individual patient relies on predictive mathematical modeling of empirical data on adverse events. The Pediatric Normal-Tissue Effects in the Clinic (PENTEC) collaborative network was formed to summarize and, when possible, to synthesize dose-volume-response relationships for a range of adverse events incident in CCS based on the literature. Normal-tissue clinical radiation biology in children is particularly challenging for many reasons: (1) Childhood malignancies are relatively uncommon-constituting approximately 1% of new incident cancers in the United States-and biologically heterogeneous, leading to many small series in the literature and large variability within and between series. This creates challenges in synthesizing data across series. (2) CCS are at an elevated risk for a range of adverse health events that are not specific to radiation therapy. Thus, excess relative or absolute risk compared with a reference population becomes the appropriate metric. (3) Various study designs and quantities to express risk are found in the literature, and these are summarized. (4) Adverse effects in CCS often occur 30, 50, or more years after therapy. This limits the information content of series with even very extended follow-up, and lifetime risk estimates are typically extrapolations that become dependent on the mathematical model used. (5) The long latent period means that retrospective dosimetry is required, as individual computed tomography-based radiation therapy plans gradually became available after 1980. (6) Many individual patient-level factors affect outcomes, including age at exposure, attained age, lifestyle exposures, health behaviors, other treatment modalities, dose, fractionation, and dose distribution. (7) Prospective databases with individual patient-level data and radiation dosimetry are being built and will facilitate advances in dose-volume-response modeling. We discuss these challenges and attempts to overcome them in the setting of PENTEC.

Event Studies with a Continuous Treatment

This paper builds on the identification results and estimation tools for continuous difference-in-difference designs in Callaway, Goodman-Bacon, and Sant'Anna (2024) to discuss aggregation strategies for event studies with continuous treatments. Estimates from continuous designs are functions of the treatment dosage/intensity variable. Nonparametric plots of these functions show heterogeneity across doses but not heterogeneity over time. Event-study-type plots of aggregated parameters achieve the opposite. We describe how partially aggregating across treatment doses and event time can lead to readable yet nuanced figures that reflect how causal effects evolve over time, potentially in different parts of the treatment dose distribution.

Development of a tumor control probability model for boron neutron capture therapy of head and neck cancer.

The tumor control probability (TCP) model has been used for estimating the response of the radiation (photon) therapy for a given treatment dose (distribution). In Taiwan, boron neutron capture therapy (BNCT) is still at the stage of the clinical trials without standard dose prescription. In this study, universal survival curve (USC) model was selected as the TCP model for BNCT. The tumor response and dose distribution from protocol I of the clinical trial of the recurrent head and neck (H&N) cancer conducted by Taipei Veterans General Hospital and National Tsing Hua University were used to verify the TCP model established in this study. The results showed that, using the USC model as a biological model of dose conversion, the TCP calculated by the generalized Equivalent Uniform Dose (gEUD)-based TCP model can be used to well correlate the relationship between the tumor response and dose distribution of the patients of recurrent H&N cancer. The result shows that 25% and 60% of TCP correspond to partial response and complete response of H&N cancer, respectively. This study also indicated that, when BNCT was used to treat recurrent H&N cancer, the minimum dose was an important factor on the efficacy of the treatment. Minimum dose of 18 Gy-w corresponds to at least 60% of TCP.

A 3D U‐Net based two stage deep learning framework for predicting dose distributions in radiation treatment planning

AbstractAutomation of the various steps of radiotherapy is gaining importance nowadays. Predicting the amount of radiation dose received by the tumor and nearby organs is one among them. Many deep learning architectures that predict the 3D dose distribution images from corresponding CT and contour images have been proposed in the literature. However, a detailed investigation has yet to be done on the significance of input images (CT and contour) in predicting dose distributions. This study introduces a novel two‐stage deep learning framework using a transfer learning technique for the same domain. The main objective of this approach is to accurately extract valuable information from the CT and contour images to determine the amount of radiation dose received by the organs. Training and testing are performed on the public dataset—OpenKBP, consisting of 340 oropharyngeal cancer patient data. The model performance is evaluated using the metrics dose score and DVH score. The proposed model outperforms the single‐stage deep learning models by 0.34% for the DVH score and 0.14% for the dose score. While comparing the mean dose difference between the predicted and actual dose values for each organ, the proposed model shows better performance in almost all cases. The results imply that medical professionals can utilize the predicted dose distributions to aid the optimization process in the treatment planning systems.

Impact of Advance techniques of radiotherapy on Organ at Risk dose distribution in treatment of Gastric cancer patient

Impact of Advance techniques of radiotherapy on Organ at Risk dose distribution in treatment of Gastric cancer patient

HPV-Associated Squamous Cell Carcinomas of the Oropharynx Treated with Curative Intent Radiotherapy: Patterns of Failure Analysis Using a Deformable Registration Methodology

<h3>Purpose/Objective(s)</h3> Although human papillomavirus (HPV)-associated squamous cell carcinomas of the oropharynx (SCCOP) have high locoregional control rates, understanding spatial patterns of recurrence remains important in the IMRT era. A standardized methodology, using deformable registration, has been proposed to more accurately assess recurrent disease volumes in the context of initial treatment dose distributions. In this study we used this methodology to analyze recurrent malignancies in HPV-associated SCCOP. <h3>Materials/Methods</h3> A single institution database was retrospectively assessed for p16 (+) SCCOP treated with curative intent, either definitively or adjuvantly, using IMRT. Recurrence required either pathologic confirmation or clinically conclusive imaging. The earliest image indicative of recurrence was identified (either CT, MRI or PET-CT) and a "recurrent GTV" (rGTV) was contoured. Local and regional recurrences in the same patient were analyzed separately. This image was deformed onto the initial CT simulation, and the deformed rGTV was categorized into five types (A-E). In Types A/B the rGTV centroid was inside the prescribed high dose distribution, and delineated "A" if the dose to 95% of the failure volume (fD95%) was ≥ 95%, versus "B" if < 95%. In Types C/D the rGTV centroid was inside the elective dose distribution, and delineated "C" if fD95% was ≥ 95%, versus "D" if < 95%. In Type E the rGTV centroid was outside the elective and high dose volume. All deformable registrations were performed using MIM treatment planning software. <h3>Results</h3> A total of 140 patients met inclusion criteria, of which 114 were treated definitively and 26 were treated adjuvantly. 17 locoregional recurrences in 16 patients were identified; 8 failed at the primary, 7 failed regionally, and 1 failed both at the primary and regionally. Recurrence was confirmed by pathology in 14 patients. Five patients were AJCC 8^th Stage I, three were Stage II, and eight were Stage III. The mean rGTV was 9.2 cc (0.1 to 60.7). Of the 17 recurrences, 11 (65%) were Type A, two (12%) were Type B, one (6%) was Type C, and three (18%) were Type E. The only Type C recurrence occurred in a patient treated on the radiotherapy alone arm on NRG HN002 within the 48 Gy elective nodal volume. Type E failures occurred in level VI-A in a Stage II base of tongue malignancy, the contralateral neck in a patient treated ipsilaterally for a Stage I tonsillar malignancy, and the base of skull in a Stage III tonsillar malignancy. <h3>Conclusion</h3> In HPV-associated SCCOP locoregional recurrences occur primarily within the high dose volume, indicating a need for improved stratification and potential intensification in a small subset of patients. Deformable registration-based patterns of failure analysis are feasible, and should be the standard reporting methodology.

DR-only Carbon-ion radiotherapy treatment planning via deep learning

PurposeTo evaluate the feasibility of patient-specific digital radiography (DR)-only treatment planning for carbon ion radiotherapy in anthropomorphic thorax-and-abdomen phantom and head-and-neck patients. MethodsThe study was conducted on the anthropomorphic phantom and head-and-neck patients. We collected computed tomography (CT) and DR images of the phantom and cone beam CT (CBCT) and DR images of the patients, respectively. Two different deep neural networks were established to correlate the relationships between DR and digitally reconstructed radiograph (DRR) images, as well as DRR and CT images. The similarity between CT and predicted CT images was evaluated by computing the mean absolute error (MAE), root mean square error (RMSE), peak signal-to-noise ratio (PSNR) and structural similarity (SSIM), respectively. Dose calculations on the predicted CT images were compared against the true CT-based dose distributions for carbon-ion radiotherapy treatment planning with intensity-modulated pencil-beam spot scanning. Relative dose differences in the target volumes and organ-at-risks were computed and three-dimensional gamma analyses (3 mm, 3%) were performed. ResultsThe average MAE, RMSE, PSNR and SSIM of the framework were 0.007, 0.144, 37.496 and 0.973, respectively. The average relative dose differences between the predicted CT- and CT-based dose distributions at the same carbon-ion irradiation settings for the phantom and the patients were <2% and ≤4%, respectively. The average gamma pass-rates were >98% for the predicted CT-based versus CT-based carbon ion plans of the phantom and the patients. ConclusionWe have demonstrated the feasibility of a patient-specific DR-only treatment planning workflow for heavy ion radiotherapy by using deep learning approach.

First application of the BIANCA biophysical model to carbon-ion patient cases

Objective. The main objective of this work consists of applying, for the first time, the BIANCA (BIophysical ANalysis of Cell death and chromosome Aberrations) biophysical model to the RBE calculation for C-ion cancer patients, and comparing the outcomes with those obtained by the LEM I model, which is applied in clinics. Indeed, the continuous development of heavy-ion cancer therapy requires modelling of biological effects of ion beams on tumours and normal tissues. The relative biological effectiveness (RBE) of heavy ions is higher than that of protons, with a significant variation along the beam path. Therefore, it requires a precise modelling, especially for the pencil-beam scanning technique. Currently, two radiobiological models, LEM I and MKM, are in use for heavy ions in scanned pencil-beam facilities. Approach. Utilizing an interface with the FLUKA Particle Therapy Tool, BIANCA was applied to re-calculate the RBE-weighted dose distribution for carbon-ion treatment of three patients (chordoma, head-and-neck and prostate) previously irradiated at CNAO, where radiobiological optimization was based on LEM I. The predictions obtained by BIANCA were based either on chordoma cell survival (RBE surv ), or on dicentric aberrations in peripheral blood lymphocytes (RBE ab ), which are indicators of late normal tissue damage, including secondary tumours. The simulation outcomes were then compared with those provided by LEM I. Main results. While in the target and in the entrance channel BIANCA predictions were lower than those obtained by LEM I, the two models provided very similar results in the considered OAR. The observed differences between RBE surv and RBE ab (which were also dependent on fractional dose and LET) suggest that in normal tissues the information on cell survival should be integrated by information more closely related to the induction of late damage, such as chromosome aberrations. Significance. This work showed that BIANCA is suitable for treatment plan optimization in ion-beam therapy, especially considering that it can predict both cell survival and chromosome aberrations and has previously shown good agreement with carbon-ion experimental data.

Comparison of dose distribution 6 MV photon in breast cancer treatment using plasticine and silicone rubber boluses

There are many cases where treatment of breast cancer was performed with thin body contours, especially after the breast mastectomy. This may lead in a larger radiation dose in the lungs, so that a bolus is needed to compensate the thin body for the optimal dose distribution. This study was aimed to compare the dose distribution in the breast cancer treatment between using commonly used of the plasticine bolus and newly developed bolus, i.e. the sillicone rubber. The study was implemented in the chest of an anthropomorphic phantom. The anthropomorphic phantom was scanned using a CT scanner without bolus and with boluses of the plasticine and the silicone rubber. The dose distribution was calculated using the Xio treatment planning system (TPS). The results show that a dose reduction of the sillicone rubber bolus that reaches the breast tissue higher than the plasticine bolus. This is because the silicone rubber bolus has a higher number electron density than the plasticine bolus. The silicone rubber bolus may produce an optimal dose homogeneity within breast cancer and relatively lower dose to the lung.

Development, Monte Carlo simulations and experimental evaluation of a 3D range-modulator for a complex target in scanned proton therapy

The purpose of this work was to develop and manufacture a 3D range-modulator (3D RM) for a complex target contour for scanned proton therapy. The 3D RM is considered to be a viable technique for the very fast dose application in patient-specific tumors with only one fixed energy. The RM was developed based on a tumor from a patient CT and manufactured with high-quality 3D printing techniques with both polymer resin and aluminum. Monte Carlo simulations were utilized to investigate its modulating properties and the resulting dose distribution. Additionally, the simulation results were validated with measurements at the Marburg Ion-Beam Therapy Centre. For this purpose, a previously developed water phantom was used to conduct fast, automated high-resolution dose measurements. The results show a very good agreement between simulations and measurements and indicate that highly homogeneous dose distributions are possible. The delivered dose is conformed to the distal as well as to the proximal edge of the target. The 3D range-modulator concept combines a high degree of dose homogeneity and conformity, comparable to standard IMPT with very short irradiation times, promising clinically applicable dose distributions for lung and/or FLASH treatment, comparable and competitive to those from conventional irradiation techniques.

The effects of set-up errors on dose distribution in radiotherapy treatment for lung cancer

The effects of set-up errors on dose distribution in radiotherapy treatment for lung cancer

The effects of set-up errors on dose distribution in radiotherapy treatment for lung cancer

Background: Our aim was to analyze the effects of set-up errors on dose distribution in radiotherapy treatment for lung cancer by using kilovoltage cone-beam CT (CBCT). Materials and Methods: In this study, we used a Varian IX linear accelerator system to perform CBCT scans of 30 lung cancer patients before radiotherapy. Subsequently, the image was matched with the planned CT, and the left and right (LR), top and bottom (SI), and front and back (AP) directions were set incorrectly. And in the CMS planning system, the center of the plan has been moved to the center of the actual scan. Finally, the dose distribution before the bed-moving is simulated. We want to explore the impact of the planned target volume setting error (PTV), the total tumor volume (GTV), and radiation of normal tissues. Results: The set-up errors of the LR, SI and AP directions were (-0.20±2.84), (-1.09±5.40), and (-2.61±2.08) mm, respectively. The 5mm error accounted for 97.8%, 73% and 92.6% in the three directions. Statistically significant differences were found in the distribution of 95%PTV dose, the average dose of PTV, 95% GTV dose and the average dose of GTV without bed-moving, compared with the original plan. Conclusions: In clinical lung cancer radiotherapy, the commonly used setting error is usually less than 5mm, most of which are along the AP direction. In this study, we found that the setting error is related to the patient's inherent characteristics and can significantly change the radiation treatment dose in the target area.

Evaluation of optimization workflow using custom-made planning through predicted dose distribution for head and neck tumor treatment.

Lack of a reference dose distribution is one of the challenges in the treatment planning used in volumetric modulated arc therapy because numerous manual processes result from variations in the location and size of a tumor in different cases. In this study, a predicted dose distribution was generated using two independent methods. Treatment planning using the predicted distribution was compared with the clinical value, and its efficacy was evaluated. Computed tomography scans of 81 patients with oropharynx or hypopharynx tumors were acquired retrospectively. The predicted dose distributions were determined using a modified filtered back projection (mFBP) and a hierarchically densely connected U-net (HD-Unet). Optimization parameters were extracted from the predicted distribution, and the optimized dose distribution was obtained using a commercial treatment planning system. In the test data from ten patients, significant differences between the mFBP and clinical plan were observed for the maximum dose of the brain stem, spinal cord, and mean dose of the larynx. A significant difference between the dose distributions from the HD-Unet dose and the clinical plan was observed for the mean dose of the left parotid gland. In both cases, the equivalent coverage and flatness of the clinical plan were observed for the tumor target. The predicted dose distribution was generated using two approaches. In the case of the mFBP approach, no prior learning, such as deep learning, is required; therefore, the accuracy and efficiency of treatment planning will be improved even for sites where sufficient training data are unavailable.

Improved Rectal Dose Distribution for External Beam Treatment of Prostate Cancers Using Hybrid Plans

Improved Rectal Dose Distribution for External Beam Treatment of Prostate Cancers Using Hybrid Plans

Quantitative Analysis of the Treatment Set Up Reliability of a Prone Breast Boost for Early Stage Breast Cancer

Adjuvant whole-breast radiation and a tumor bed boost for early-stage breast cancer can be delivered in the supine or prone position. Delivering the boost in the prone position has the advantage of removing the supine simulation CT and the capability of obtaining the total treatment dose distribution. However, the reliability of daily prone boost set up is largely unknown, and imaging is used for treatment verification. Here we evaluate the reliability of a daily clinical setup protocol for a prone mini-tangent boost, using daily cone beam CT (CBCT) to verify the adequacy of target coverage. We retrospectively reviewed 13 patients treated with a prone mini-tangent boost. The target (CTV) was the tumor bed without further expansion. Distance from CTV to block edge was 1.5cm. The boost prescription was 10Gy in 5 fractions. Coverage goals were the treating physician’s discretion, However, in all cases the planned dose to 90% of the CTV (D90) > 90% of prescription. Patients were positioned daily using a clinical setup with visual verification. Port films were taken to verify day 1 setup and when there was concern about the daily clinical setup. A CBCT was then acquired. If needed, additional shifts were made based on the CBCT, often followed by port films. Retrospectively, the simulation CT was independently registered to the daily CBCTs by a physician, and a daily tumor bed contour was generated. The treatment plan was transferred to the daily CBCT and delivered dose was calculated. To assess the reliability of clinical setup prior to CBCT acquisition, we assessed how often the daily D90 was < 90% of prescription dose (D90 < 90%) and how often the daily volume receiving full prescription dose (V100daily) did not receive the planned V100 (V100plan) by > 10% (V100plan-V100daily > 10%). Twelve patients with full imaging details were analyzed. Of 60 analyzable daily fractions, D90 < 90% for 3/60 fractions (5%), and V100plan-V100daily > 10% for 11/60 fractions (18%). Post-CBCT shifts were made for 1 fraction with D90 < 90% and for 2 fractions with V100plan-V100daily > 10%. Fractions for which coverage did not meet reliability metrics most commonly involved superficial tumor beds that extended into the region of subcutaneous dose build-up. In all such cases, allowing a portion of the target to receive less than prescription dose was deemed acceptable by the treating physician. We found that a daily clinical treatment setup for a prone boost was reliable in most cases. Addition of a CBCT was helpful to identify clinical setup variability. Treatment of a superficial tumor bed may be more sensitive to small variations in daily treatment setup due to the dose gradient across the target. When superficial target coverage is critical, supine boost positioning may be considered.

Computational evaluation of dose distribution for BNCT treatment combined with X-ray therapy or proton beam therapy

In this study, we performed Monte Carlo simulations to accurately reflect the beam delivery systems including patient-specific irradiation devices of X-ray and proton beam therapies. The dose distributions obtained from the simulations for X-rays or proton beams were successfully combined to the dose distribution of boron neutron capture therapy (BNCT), which was calculated by a treatment planning system called Tsukuba Plan. The results demonstrate the feasibility of dose evaluation for BNCT combined with other radiotherapy modalities using the Tsukuba Plan.

Design and Implementation of a Monte Carlo Framework for Assessment of Spoiler Applications in Abutting Electron Fields.

Background: Field matching problems in abutting electron fields can be managed by using spoilers.Objective: The aim of this study was to design a Monte Carlo framework for the assessment of spoiler application in abutting electron fields.Material and Methods: In this experimental study, a Siemens Primus treatment head was simulated for a 5 MeV electron beam using BEAMnrc, DOSXYZnrc and EGSnrc user codes. Validation of beam model was done by measurement using a MP3-M water tank and a Semi-flex Chamber-31010 (PTW, Freiburg, Germany). An in-house routine was developed to calculate the combined isodose curves resulting from simulated adjacent fields. The developed framework was analyzed using PMMA and chromium spoilers.Results: The penumbra width increased from 27.5 mm for open fields to 42 mm for PMMA and 40 mm for chromium. The maximum junction dose reduced from 115% for open fields to 107% for PMMA and 108% for chromium. R90 reduced about 6 mm for PMMA and 3 mm for chromium. Uniformity index reduced from 93% to 77% for both spoilers. Surface dose increased from 79% to 89% for PMMA and 88% for chromium.Conclusion: Using spoilers, penumbra width at the surface was increased, size and depth of hot spots as well as the therapeutic range were reduced and dose homogeneity at the junction of abutting electron fields was improved. For both spoilers, the uniformity index reduced, and surface percent dose increased. The results of this research can be used to optimize dose distribution in electron beam treatment using abutting fields.

The advantages of carbon fiber based orthopedic devices in patients who have to undergo radiotherapy.

Background and Objectives:The modern approach to primary and secondary muscular skeletal tumors is multidisciplinary. The right combination of chemotherapy, surgery and radiotherapy (RT) makes obtaining local and distant disease more likely. When surgery is indicated, radiotherapy often has a fundamental role as an adjuvant treatment; however, the titanium alloy instrumentations interfere with Radiotherapy setting, decreasing its effectiveness. It is common opinion that carbon fiber-reinforced devices are convenient in case of adjuvant RT in muscular skeletal oncology. The aim of the study is to support this intuition with experimental data, verifying the more accurate estimation of the delivered dose during RT, comparing Carbon Fiber-Reinforced PEEK (CFRP) plates with titanium-alloy orthopedic devices in order to evaluate their effects on target volume identification and dose distribution for radiation treatment.Methods:Phantoms were then irradiated with a linear accelerator Varian 2100 C/D with photon beams of 6 and 15 MV energies. Absorbed dose in the point of interest was verified by EBT3 gafchromic films above and below the two materials. Images from CT simulations were also analyzed in terms of Hounsfield numbers in patients with titanium and carbon fiber orthopedic implants in the spine or in the femur.Results:For a 6 MV photon beam, the doses measured just under the titanium-alloy plate were less than approximately 20% of the value calculated by the TPS. For a 15 MV beam energy, these differences were slightly lower. Using CFRP plate, the difference between measured and calculated doses was within ±3% for both energies, which was comparable with the statistical uncertainties. In the cases of simulated treatment of humerus titanium implants, the difference varies in range ± 10% with hot spot of + 10% and cold spot of -15%.Conclusions:The use of CFRP for orthopedic devices and implants provides a valuable advantage in identifying the target due to the reduction of artifacts. Clear imaging of the soft tissues surrounding the bone is useful and reduces the discrepancies between calculated/delivered and measured doses, generating a more homogeneous dose distribution. Furthermore, there is a significant benefit in detecting the state of disease in CT imaging during the follow-up of treated patients. In-vivo studies are encouraged to verify whether a more effective radiotherapy leads to a decrease in local recurrence and local progression. (www.actabiomedica.com)

Dose distribution in boron neutron capture therapy for the treatment of brain cancer

This work presents a study of the influence of the field size of an epithermal neutron beam on the dose distribution in treatments with boron neutron capture therapy using an anthropomorphic voxel-based simulator. To calculate the doses in the tissues and organs of the head, the Monte Carlo N-Particle radiation transport code is used. The results suggest the possibility of using a beam of 6 cm in diameter for the treatment of tumours in the frontal lobe and parietal regions. With a beam of 10 cm in diameter, we could treat tumours located in the frontal lobe, parietal lobe and thalamus. The work also shows that the contribution of the secondary components (gamma rays, fast and thermal neutrons) in the calculation of the total dose can result in up to 15% of the dose in the tumour tissue, 68% of the dose in the healthy brain tissue and 87% of the dose in the non-cephalic regions.

Неопределенности поглощенной дозы, измеренной дозиметром GAFCHROMIC EBT3 на клинических электронных и фотонных пучках медицинских ускорителей

Purpose: Investigation of the relative errors of absorbed dose measurement based on polymer films Gafchromic EBT3 for clinical electron and photon beams of medical accelerators.&#x0D; Material and methods: Polymer Gafchromic EBT3 films were calibrated using different radiation beams, namely photon and electron beams of Elekta Axesse medical accelerator with beam energy equal to 10 MV and 10 MeV, correspondingly, and electron beam of a betatron for intraoperative radiotherapy with beam energy equal to 6 MeV. The film pieces were irradiated by the uniform dose field in the dose range from 0.5 to 40 Gy. The dose value was controlled by cylindrical ionization chamber in the case of Elekta Axesse accelerator and by the Markus parallel chamber in the case of betatron. The irradiated films were scanned using Epson Perfection V750 Pro flatbed scanner in 16 bit RGB color mode with 150 dpi resolution. The red and green channels were used for further analysis. The central part of each film was used for calculation of average values of net optical density and its root-mean-square. As a result, the calibration curves, i.e. dependence on the reference absorbed dose measured by ionization chamber on the net optical density were constructed taking into account uncertainties of dose measurement and optical density measurement.&#x0D; Results: The relative uncertainty for the dose measurement lies within 7 % for low doses (less than 1 Gy) and within 4 % for higher doses. The green channel is less sensitive to the radiation, but its relative uncertainty values are in general 1–2 % lower than the ones for the red channel. The use of different calibration sources results in different calibration curves with difference up to ±6 % for the green channel.&#x0D; Conclusion: The polymer Gafchromic EBT3 films could be used for absorbed dose measurement for the doses not less than 0.5 Gy. For lower dose values the dose measurement uncertainty caused by statistical reasons amounts 15 %. For dose values of about 1 Gy and higher the dose measurement uncertainty amounts 5 % that allows to use the films for transverse and longitudinal prescription treatment dose distribution measurement with very high spatial resolution.