Comparison of the dose distribution of the VMAT radiotherapy technique depending on the beam used: FFF-X10MV and FFF-X15MV.

Background: The aim of the study was to answer the question of whether flattening filter (FF) and flattening filter-free (FFF) beams can be used alternately in the volumetric modulated arc therapy (VMAT) treatment technique, regardless of the size of the irradiated volume [small (S) or large (L) planning target volume (PTV)]. Materials and methods: Two groups of patients were examined: a group with a S-PTV-laryngeal cancer and a group with a L-PTV - gynecological volume. For each patient, two treatment plans were made for beams (energies): FFF-X10MV and FF-X15MV. Then, a statistical analysis, nonparametric test, and independent groups were performed, comparing the beams' impact on the analyzed treatment plans. Results: In the case of laryngeal irradiation (S-PTV), there are no statistically significant differences between the energy used and the assessed parameters of the plan. In the case of gynecological volume (L-PTV), only statistically significant differences were noted for the number of monitor units depending on the energy used. For a large irradiated volume (gynecological case), the use of FFF beams increases the number of monitor units by 39,4% in relation to the FF beam. Conclusions: In the case of gynecological neoplasms, statistically significant differences were found in the number of monitor units. Therefore, in the case of irradiation of L-PTV, it is recommended that flattening-filtering beams are used due to the smaller number of monitors. In the case of S-PTV, no statistically significant differences were found between the types of beams used (FF or FFF) and the treatment plan parameters analyzed in the study.

Physical parameters in thermal imaging of basal cell cancer patients treated with high-dose-rate brachytherapy - first study.

Background: The basal cell carcinoma (BCC) is often treated by surgery or radiotherapy using ionizing radiation. While there is an established diagnostic path before treatment and also for the follow-up there are no good noninvasive methods objectifying irradiated area evolution during treatment. The main goal of preliminary studies was to try to answer if there are any useful information that can be derived from temperature effects of high-dose-rate (HDR) brachytherapy in treatment of BCC. Moreover, the temperature gradient was introduced as a physical parameter characterizing the thermal map of the lesion, its surroundings and reference area, which provided information about cancer tissue thermal reaction to brachytherapy. Materials and methods: Thirty-three patients suffering from BCC were monitored with thermovision during the brachytherapy treatment. All lesions were diagnosed as superficial and were confirmed with histopathology examination. Results: Results of the study showed two groups of patients characterized with two thermal maps and temperature gradient describing the lesion and surrounding area of BCC. The first group was characterized by higher temperature of the lesion than the surrounding tissue temperature (mean dT = 0,41°) whereas the other one, with lower lesion temperature (mean dT = -0.42°). It seems that the temperature changes observed in designated areas before and after therapy may provide physicians with additional information which could be useful in planning the treatment process, especially when considering temperature gradient changes during therapy. Conclusions: Although the data obtained indicate the possibilities of temperature distribution in pre-irradiation cases, further research is required for estimation of clinical effects of treatment.

Influence of optional measurement parameters in the Eclipse treatment planning system on the quality of the dosimetric model of the biomedical accelerator using the Acuros XB algorithm.

Background: To properly configure a treatment planning system, a measurement data set is needed, which consists of the values required for its configuration. The aim is to obtain a dosimetric model of the beam that is as compatible as possible with the measured values. The set of required data can be supplemented with optional values. The aim of the study was to assess the influence of optional measurement data on the compliance of the calculations with the measurements. Materials and methods: Dosimetric measurements, model configuration and dose distribution calculations were performed for the photon radiation beams generated by the VMS TrueBeam® linear accelerator. Beams were configured on an Eclipse™ v. 15.6 system using the Acuros v. 15.6 algorithm. The measured and calculated data were entered into the Alfard™ software for comparison with the calculated dose distributions. In the last stage, the absolute dose values at the designated points were also compared. The obtained data were statistically analysed with Statistica™ v. 13.3. Results: The work showed that the differences in the shape of the beam profile, depth dose and the dose value in points were not related to the use of optional data. Differences in dose distributions are within the tolerance. It cannot be determined under which conditions the use of optional data has a more favourable effect on the reflection of the actual dose values. Conclusions: The use of optional data in modelling photon radiation beams does not significantly improve the compliance of the calculated and measured dose values.

Portal dosimetry in radiotherapy repeatability evaluation.

The accuracy of radiotherapy is the subject of continuous discussion, and dosimetry methods, particularly in dynamic techniques, are being developed. At the same time, many oncology centers develop quality procedures, including pretreatment and online dose verification and proper patient tracking methods. This work aims to present the possibility of using portal dosimetry in the assessment of radiotherapy repeatability. The analysis was conducted on 74 cases treated with dynamic techniques. Transit dosimetry was made for each collision-free radiation beam. It allowed the comparison of summary fluence maps, obtained for fractions with the corresponding summary maps from all other treatment fractions. For evaluation of the compatibility in the fluence map pairs (6798), the gamma coefficient was calculated. The results were considered in four groups, depending on the used radiotherapy technique: stereotactic fractionated radiotherapy, breath-hold, free-breathing, and conventionally fractionated other cases. The chi2 or Fisher's exact test was made depending on the size of the analyzed set and also Mann-Whitney U-test was used to compare treatment repeatability of different techniques. The aim was to test whether the null hypothesis of error-free therapy was met. The patient is treated repeatedly if the P-value in all the fluence maps sets is higher than the level of 0.01. The best compatibility between treatment fractions was obtained for the stereotactic technique. The technique with breath-holding gave the lowest percentage of compliance of the analyzed fluence pairs. The results indicate that the repeatability of the treatment is associated with the radiotherapy technique. Treated volume location is also an essential factor found in the evaluation of treatment accuracy. The EPID device is a useful tool in assessing the repeatability of radiotherapy. The proposed method of fluence maps comparison also allows us to assess in which therapeutic session the patient was treated differently from the other fractions.

The Use of Thermal Imaging in the Evaluation of Temperature Effects of Radiotherapy in Patients after Mastectomy-First Study.

The aim of the study was to evaluate the temperature parameter of the breast area in patients undergoing radiotherapy at various intervals. The relationship between temperature changes on the patient's skin and the time after the end of radiotherapy was studied. Measurements with a thermal imaging camera were performed in a group of twelve volunteers. Six of them were healthy women who did not have thermal asymmetry between the breasts, whereas six were diagnosed with breast cancer and underwent mastectomy due to the advanced stage of the disease. The patients were qualified for radiation therapy. Thermographic examinations were performed before treatment, two months later and then six months after the end of the treatment. Temperature differences between the healthy breasts and the treated areas were assessed. Additionally, the correlation between a patient's skin temperature changes and the time after the end of radiotherapy was analyzed. The highest skin temperature increase (1.47 °C) was observed 6 months after the end of RT compared to the measurement before treatment. It seems that thermovision may bring a new tool for quantitative analyses of the temperature effects of radiotherapy.

Using beam profile inflection point in process of treatment planning system verification.

BACKGROUND: The comparison between profiles during the commissioning of the treatment planning system is an essential procedure. It is impossible to designate a field size for off-axis, wedged, and FFF beams directly by using the definition of the on-axis symmetric field size. This work proposes the use of different characteristic points as indicators of the field size for commissioning and QA purposes. This work aimed to search for the beam profile's characteristic points and use them for the TPS commissioning purposes. MATERIALS AND METHODS: The proposal is to use profile inflection points as the beam profile characteristic points. The usage of dedicated software allowed for comparing distances between inflection points and between points of 50% intensity. For the off-axis, wedged, and FFF fields, comparisons were made to the nominal field sizes. RESULTS: Distances between inflection points proved to be different by less than 1 mm from nominal field sizes for all kinds of investigated beams. CONCLUSIONS: Inflection points are convenient for comparing the off-axis, wedged, and FFF field sizes because of their independence from profile normalization. With finite accuracy, the inflection points could be used for the above kind of beam sizes designation.

IMRT/VMAT dose distributions generated for HD ® and Millennium ® collimators TrueBeam ® and Clinac ® accelerators.

AIM: The aim of this study is to answer the question whether the calculated dose distributions for HD and Millennium collimators (Varian Medical Systems) are equivalent for large treatment volumes. BACKGROUND: Modern biomedical linacs are equipped with multileaf collimators where leaves can be of different widths. Thinner leaves allow better fit to desired (tumor) shape. At the same time, however, the maximum size of the field that can be obtained with the collimator is also reduced. Varian Medical Systems HD and Millennium collimators can be a good sample. They have 40 cm or 22 cm × 40 cm maximal field size at the isocenter, respectively. MATERIALS AND METHODS: This paper presents the comparison of selected statistical and dosimetric parameters achieved for treatment plans where the beams for a HD collimator had to be merged because of the size of the tumor volume. RESULTS AND DISCUSSION: Achieved results show that, independently from irradiated volume, there is no statistically significant difference for calculated dose distributions, integral doses, MU values and coefficients evaluating dose distributions for HD and Millennium collimators. CONCLUSIONS: Results show that both types of collimators can be used interchangeably for preparing the treatment plans for large tumor volume without quality reduction of the prepared treatment plan.

Can high dose rates used in cancer radiotherapy change therapeutic effectiveness?

Current cancer radiotherapy relies on increasingly high dose rates of ionising radiation (100-2400 cGy/min). It is possible that changing dose rates is not paralleled by treatment effectiveness. Irradiating cancer cells is assumed to induce molecular alterations that ultimately lead to apoptotic death. Studies comparing the efficacy of radiation-induced DNA damage and apoptotic death in relation to varying dose rates do not provide unequivocal data. Whereas some have demonstrated higher dose rates (single dose) to effectively kill cancer cells, others claim the opposite. Recent gene expression studies in cells subject to variable dose rates stress alterations in molecular signalling, especially in the expression of genes linked to cell survival, immune response, and tumour progression. Novel irradiation techniques of modern cancer treatment do not rely anymore on maintaining absolute constancy of dose rates during radiation emission: instead, timing and exposure areas are regulated temporally and spatially by modulating the dose rate and beam shape. Such conditions may be reflected in tumour cells' response to irradiation, and this is supported by the references provided.

Integral dose: Comparison between four techniques for prostate radiotherapy.

AIM: Comparisons of integral dose delivered to the treatment planning volume and to the whole patient body during stereotactic, helical and intensity modulated radiotherapy of prostate. BACKGROUND: Multifield techniques produce large volumes of low dose inside the patient body. Delivered dose could be the result of the cytotoxic injuries of the cells even away from the treatment field. We calculated the total dose absorbed in the patient body for four radiotherapy techniques to investigate whether some methods have a potential to reduce the exposure to the patient. MATERIALS AND METHODS: We analyzed CyberKnife plans for 10 patients with localized prostate cancer. Five alternative plans for each patient were calculated with the VMAT, IMRT and TomoTherapy techniques. Alternative dose distributions were calculated to achieve the same coverage for PTV. Integral Dose formula was used to calculate the total dose delivered to the PTV and whole patient body. RESULTS: Analysis showed that the same amount of dose was deposited to the treated volume despite different methods of treatment delivery. The mean values of total dose delivered to the whole patient body differed significantly for each treatment technique. The highest integral dose in the patient's body was at the TomoTherapy and CyberKnife treatment session. VMAT was characterized by the lowest integral dose deposited in the patient body. CONCLUSIONS: The highest total dose absorbed in normal tissue was observed with the use of a robotic radiosurgery system and TomoTherapy. These results demonstrate that the exposure of healthy tissue is a dosimetric factor which differentiates the dose delivery methods.

Extreme heterogeneity of myeloablative total body irradiation techniques in clinical practice: a survey of the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation.

BACKGROUND: Total body irradiation (TBI) is widely used for conditioning before hematopoietic cell transplantation. Its efficacy and toxicity may depend on many methodological aspects. The goal of the current study was to explore current clinical practice in this field. METHODS: A questionnaire was sent to all centers collaborating in the European Group for Blood and Marrow Transplantation and included 19 questions regarding various aspects of TBI. A total of 56 centers from 23 countries responded. RESULTS: All centers differed with regard to at least 1 answer. The total maximum dose of TBI used for myeloablative transplantation ranged from 8 grays (Gy) to 14.4 Gy, whereas the dose per fraction was 1.65 Gy to 8 Gy. A total of 16 dose/fractionation modalities were identified. The dose rate ranged from 2.25 centigrays to 37.5 centigrays per minute. The treatment unit was linear accelerator (LINAC) (91%) or cobalt unit (9%). Beams (photons) used for LINAC were reported to range from 6 to 25 megavolts. The most frequent technique used for irradiation was "patient in 1 field," in which 2 fields and 2 patient positions per fraction are used (64%). In 41% of centers, patients were immobilized during TBI. Approximately 93% of centers used in vivo dosimetry with accepted discrepancies between the planned and measured doses of 1.5% to 10%. In 84% of centers, the lungs were shielded during irradiation. The maximum accepted dose for the lungs was 6 Gy to 14.4 Gy. CONCLUSIONS: TBI is an extremely heterogeneous treatment modality. The findings of the current study should warrant caution in the interpretation of clinical studies involving TBI. Further investigation is needed to evaluate how methodological differences influence outcome. Efforts to standardize the method should be considered.

Clinical examples of 3D dose distribution reconstruction, based on the actual MLC leaves movement, for dynamic treatment techniques.

AIM: To present practical examples of our new algorithm for reconstruction of 3D dose distribution, based on the actual MLC leaf movement. BACKGROUND: DynaLog and RTplan files were used by DDcon software to prepare a new RTplan file for dose distribution reconstruction. MATERIALS AND METHODS: FOUR DIFFERENT CLINICALLY RELEVANT SCENARIOS WERE USED TO ASSESS THE FEASIBILITY OF THE PROPOSED NEW APPROACH: (1) Reconstruction of whole treatment sessions for prostate cancer; (2) Reconstruction of IMRT verification treatment plan; (3) Dose reconstruction in breast cancer; (4) Reconstruction of interrupted arc and complementary plan for an interrupted VMAT treatment session of prostate cancer. The applied reconstruction method was validated by comparing reconstructed and measured fluence maps. For all statistical analysis, the U Mann-Whitney test was used. RESULTS: In the first two and the fourth cases, there were no statistically significant differences between the planned and reconstructed dose distribution (p = 0.910, p = 0.975, p = 0.893, respectively). In the third case the differences were statistically significant (p = 0.015). Treatment plan had to be reconstructed. CONCLUSION: Developed dose distribution reconstruction algorithm presents a very useful QA tool. It provides means for 3D dose distribution verification in patient volume and allows to evaluate the influence of actual MLC leaf motion on the dose distribution.

Low-Dose Radiotherapy for Patients with Pneumonia Due to COVID-19: A Single-Institution Prospective Study.

PURPOSE: Results of the low-dose radiation therapy (LDRT) in patients with pneumonia due to COVID-19 has been presented. METHODS: Fifteen patients received a single-fraction radiation dose of 1 Gy to the bilateral lungs due to pre-ARDS pneumonia in the course of COVID-19. Follow-up was performed on days 1, 3, 5, 7, 14 after LDRT. RESULTS: Eleven patients (73%) were released up until day 28. Median hospitalization was 20 days; 28-day mortality was 13%. Median O2 saturation improved within 24 h after LDRT in 14/15, with median SpO2 values of 84.5% vs. 87.5% p = 0.016, respectively. At day 14 of hospitalization, 46% did not require oxygen supplementation. Significant decline in CRP and IL-6 was observed within 24 h post LDRT. No organ toxicities were noted. CONCLUSION: LDRT is feasible, well tolerated and may translate to early clinical recovery in patients with severe pneumonia. Further studies are needed to determine optimal candidate, time and dose of LDRT for COVID-19 patients with pneumonia.

Comparison of dose distribution in IMRT and RapidArc technique in prostate radiotherapy.

AIM: The aim was to provide a dosimetric comparison between IMRT and RapidArc treatment plans with RPI index with simultaneous comparison of the treatment delivery time. BACKGROUND: IMRT and RapidArc provide highly conformal dose distribution with good sparing of normal tissues. However, a complex spatial dosimetry of IMRT and RapidArc plans hampers the evaluation and comparison between plans calculated for the two modalities. RPI was used in this paper for treatment plan comparisons. The duration of the therapeutic session in RapidArc is reported to be shorter in comparison to therapeutic time of the other dynamic techniques. For this reasons, total treatment delivery time in both techniques was compared and discussed. MATERIALS AND METHODS: 15 patients with prostate carcinoma were randomly selected for the analysis. Two competitive treatment plans using respectively the IMRT and RapidArc techniques were computed for each patient in Eclipse planning system v. 8.6.15. RPIwin(®) application was used for RPI calculations for each treatment plan. Additionally, total treatment time was compared between IMRT and RapidArc plans. Total treatment time was a sum of monitor units (MU) for each treated field. RESULTS: The mean values of the RPI indices were insignificantly higher for IMRT plans in comparison to rotational therapy. Comparison of the mean numbers of monitor units confirmed that the use of rotational technique instead of conventional static field IMRT can significantly reduce the treatment time. CONCLUSION: Analysis presented in this paper, demonstrated that RapidArc can compete with the IMRT technique in the field of treatment plan dosimetry reducing the time required for dose delivery.

Beam rate influence on dose distribution and fluence map in IMRT dynamic technique.

AIM: To examine the impact of beam rate on dose distribution in IMRT plans and then to evaluate agreement of calculated and measured dose distributions for various beam rate values. BACKGROUND: Accelerators used in radiotherapy utilize some beam rate modes which can shorten irradiation time and thus reduce ability of patient movement during a treatment session. This aspect should be considered in high conformal dynamic techniques. MATERIALS AND METHODS: Dose calculation was done for two different beam rates (100 MU/min and 600 MU/min) in an IMRT plan. For both, a comparison of Radiation Planning Index (RPI) and MU was conducted. Secondly, the comparison of optimal fluence maps and corresponding actual fluence maps was done. Next, actual fluence maps were measured and compared with the calculated ones. Gamma index was used for that assessment. Additionally, positions of each leaf of the MLC were controlled by home made software. RESULTS: Dose distribution obtained for lower beam rates was slightly better than for higher beam rates in terms of target coverage and risk structure protection. Lower numbers of MUs were achieved in 100 MU/min plans than in 600 MU/min plans. Actual fluence maps converted from optimal ones demonstrated more similarity in 100 MU/min plans. Better conformity of the measured maps to the calculated ones was obtained when a lower beam rate was applied. However, these differences were small. No correlation was found between quality of fluence map conversion and leaf motion accuracy. CONCLUSION: Execution of dynamic techniques is dependent on beam rate. However, these differences are minor. Analysis shows a slight superiority of a lower beam rate. It does not significantly affect treatment accuracy.

Comparison of the Thermal Reaction of Patients after Conserving Procedures and after Mastectomy to the Radiation Dose Obtained during Radiotherapy.

The main aim of the study was to compare the temperature response of the body to the dose received during breast cancer radiotherapy. The control group consisted of 50 healthy volunteers. They underwent one thermographic examination and compared the temperatures between the left and right breasts. The research group consisted of 50 patients. Based on the treatment plan, the area PTV and isodose was marked on the thermograms. Five thermographs were performed in each patient (before radiotherapy and in each week of treatment). A qualitatively similar increase in mean temperature during treatment was observed in both subgroups in the analyzed areas. The highest increase in temperature was obtained in the third week of treatment. Compared with the value before treatment, the increase in the mean temperature in PTV in patients after partial surgery was 0.78 °C, these values are statistically significant p = 0.000055. In the case of post-mastectomy patients, 0.8 °C was obtained, these values are statistically significant p = 0.00369. In addition, strong correlation was calculated between isodoses read from treatment plans and isotherms obtained from the analysis of thermal images. In post-mastectomy patients for PTV r = 0.77, 30 Gy r = 0.94, 20 Gy r = 0.96, and 10 Gy r = 0.75. For patients after partial surgery for PTV r = 0.74, 30 Gy r = 0.89, 20 Gy r = 0.83, and 10 Gy r = 0.89. Infrared thermography seems to be a useful method of assessing the thermal response of the body to the dose received during radiotherapy of breast cancer and may be a clinically useful method of assessing the early skin response to radiation.

The Use of Infrared Thermography in the Assessment of Thermal Reaction of Patients Treated with Radiotherapy after Breast-Conserving Procedures.

The aim of the study was to assess the usefulness of the infrared thermography method in the assessment of the body's thermal reaction in patients during radiotherapy. Studies have shown how the temperature distribution changes with the dose of radiation used in each treatment week. Fifty-four patients participated in the study. The control group consisted of healthy patients, among whom the difference in mean temperatures between the breasts was checked. The study group included patients after conserving procedures qualified for radiotherapy. Measurements were taken and analyzed for each patient during each week of treatment. The target area (marked by a doctor) and the 30 Gy, 20 Gy and 10 Gy isodoses (generated from the treatment plan) were transferred on thermograms and then analyzed. This way of defining the observed areas is the most accurate and individually adjusted to each treated patient. The analysis showed an increase in temperature in the tested body surface areas, whereas the highest average temperature value was achieved during the third week of treatment. The observations may be used to evaluate the skin reaction from radiation; however, they require further studies and new quantitative parameters.

Long-Term Skin Temperature Changes after Breast Cancer Radiotherapy.

The aim of the study was to use thermal imaging to evaluate long-term chest temperature changes in patients who had previously been treated with radiotherapy. The examination with a thermal imaging camera involved 144 women-48 of them were patients after RT, 48 were females before breast cancer radiotherapy and the last group of participants were 48 healthy women. All patients (before and after radiotherapy) were divided into women after mastectomy and those after conservative surgery. In addition, the first group of women, those who had received radiotherapy, were divided into three other groups: up to 1 year after RT, over 1 year and up to 5 years after RT and over 5 years after RT. Due to this, it was possible to compare the results and analyse the differences between the temperature in the healthy and treated breasts. The comparison of obtained temperature results showed that the area treated by ionizing radiation is characterized by a higher temperature even a few years after the finished treatment. It is worth mentioning that despite the fact that the difference was visible on the thermograms, the patients had no observable skin lesion or change in color at the treatment site. For the results of the study provided for the group of healthy patients, there were no significant differences observed between the average temperatures in the breasts. The use of thermal imaging in the evaluation of skin temperature changes after radiotherapy showed that the average temperature in the treated breast area can change even a long time after treatment.

Twelve-Month Evaluation of Temperature Effects of Radiotherapy in Patients after Mastectomy.

The aim of this study was to verify the changes in the temperature distribution within the breast at twelve months after the end of radiotherapy for breast cancer. The study included twenty-four women. The first test group consisted of twelve women who underwent breast mastectomy and qualified for radiotherapy according to standard medical treatment procedures. The second group included twelve healthy women. The tests were conducted before treatment with radiation therapy and two months, six months, nine months, and one year after the end of treatment. The mean temperature values changed depending on the time that had elapsed since the end of treatment. The highest temperature increase in all patients was observed six months after the end of radiotherapy. This research has confirmed that the assessment of temperature changes in the breast area after radiotherapy can evaluate the severity and lesions in the time course of the radiation reaction.

Bystander effects induced by direct and scattered radiation generated during penetration of medium inside a water phantom.

BACKGROUND: The biological effects of ionizing radiation have long been thought to results from direct targeting of the nucleus leading to DNA damage. Over the years, a number of non-targeted or epigenetic effects of radiation exposure have been reported where genetic damage occurs in cells that are not directly irradiated but respond to signals transmitted from irradiated cells, a phenomenon termed the "bystander effects". AIM: We compared the direct and bystander responses of human A 549, BEAS-2-B and NHDF cell lines exposed to both photon (6 MV) and electron (22 MeV) radiation inside a water phantom. The cultures were directly irradiated or exposed to scattered radiation 4 cm outside the field. In parallel, non-irradiated cells (termed bystander cells) were incubated in ICM (irradiation conditioned medium) collected from another pool of irradiated cells (termed donor cells). MATERIALS AND METHODS: In directly irradiated cells as well as ICM-treated cells, the frequency of micronuclei and condensation of chromatin characteristic for the apoptotic process were estimated using the cytokinesis-block micronucleus test. RESULTS: In all tested cell lines, radiation induced apoptosis and formation of micronuclei. A549 and BEAS-2B cells cultured in ICM showed increased levels of micronuclei and apoptosis, whereas normal human fibroblasts (NHDF line) were resistant to bystander response. In A549 and BEAS-2B cells placed outside the radiation field and exposed to scattered radiation the formation of micronuclei and induction of apoptosis were similar to that after ICM-treatment. CONCLUSION: Results suggest that the genetic damage in cells exposed to scattered radiation is caused by factors released by irradiated cells into the medium rather than by DNA damage induced directly by X rays. It seems that bystander effects may have important clinical implications for health risk after low level radiation exposure of cells lying outside the radiation field during clinical treatment.

Correlation between Isotherms and Isodoses in Breast Cancer Radiotherapy-First Study.

The study is focused on correlation of isotherms derived from thermal images with an isodoses describing treatment plan for patients with breast cancer treated by radiotherapy. The irradiated area covered the part of the body after mastectomy. The study included patients diagnosed with breast cancer who were qualified for radiotherapy treatment. All patients were monitored during each treatment week during the entire radiotherapy process. The measurements were made under strictly defined conditions. In the treatment planning system (TPS), the specific plan was created for each patient. Spatial dose distribution in the patient's body was obtained and presented by the isodoses (lines connecting points with the same dose values). The following areas from the treatment planning system were plotted on the thermograms: target (tumor area) and isodose: 45 Gy, 40 Gy, 30 Gy, 20 Gy and 10 Gy. The obtained results indicated a high correlation between magnitude of the dose represented as the isodose and the temperature of the treated skin. Moreover, preliminary analysis showed a repeatable increase of the mean temperature in the irradiated area during the treatment.