Impact of chrono-radiotherapy on the prognosis and treatment-related toxicity in patients with locally advanced nasopharyngeal carcinoma: A multicenter propensity-matched study.

The timing of radiotherapy (RT) delivery has been reported to affect both cancer survival and treatment toxicity. However, the association among the timing of RT delivery, survival, and toxicity in locally advanced nasopharyngeal carcinoma (LA-NPC) has not been investigated. We retrospectively reviewed patients diagnosed with LA-NPC who received definitive RT at multiple institutions. The median RT delivery daytime was categorized as morning (DAY) and night (NIGHT). Seasonal variations were classified into the darker half of the year (WINTER) and brighter half (SUMMER) according to the sunshine duration. Cohorts were balanced according to baseline characteristics using propensity score matching (PSM). Survival and toxicity outcomes were evaluated using Cox regression models. A total of 355 patients were included, with 194/161 in DAY/NIGHT and 187/168 in WINTER/SUMMER groups. RT delivered during the daytime prolonged the 5-year overall survival (OS) (90.6% vs. 80.0%, p = 0.009). However, the significance of the trend was lost after PSM (p = 0.068). After PSM analysis, the DAY cohort derived a greater benefit in 5-year progression-free survival (PFS) (85.6% vs. 73.4%, p = 0.021) and distant metastasis-free survival (DMFS) (89.2% vs. 80.8%, p = 0.051) in comparison with the NIGHT subgroup. Moreover, multivariate analysis showed that daytime RT was an independent prognostic factor for OS, PFS, and DMFS. Furthermore, daytime RT delivery was associated with an increase in the incidence of leukopenia and radiation dermatitis. RT delivery in SUMMER influenced only the OS significantly (before PSM: p = 0.051; after PSM: p = 0.034). There was no association between toxicity and the timing of RT delivery by season. In LA-NPC, the daytime of radical RT served as an independent prognostic factor. Furthermore, RT administered in the morning resulted in more severe toxic side effects than that at night, which needs to be confirmed in a future study.

Killing two birds with one stone: Abscopal effect mechanism and its application prospect in radiotherapy.

Abscopal effects are characterized by the emergence of neoplasms in regions unrelated to the primary radiation therapy site, displaying a gradual attenuation or regression throughout the progression of radiation therapy, which have been of interest to scientists since Mole's proposal in 1953. The incidence of abscopal effects in radiation therapy is intricately linked to the immune system, with both innate and adaptive immune responses playing crucial roles. Biological factors impacting abscopal effects ultimately exert their influence on the intricate workings of the immune system. Although abscopal effects are rarely observed in clinical cases, the underlying mechanism remains uncertain. This article examines the biological and physical factors influencing abscopal effects of radiotherapy. Through a review of preclinical and clinical studies, this article aims to offer a comprehensive understanding of abscopal effects and proposes new avenues for future research in this field. The findings presented in this article serve as a valuable reference for researchers seeking to explore this topic in greater depth.

PErspective and current status of Radiotherapy Service in IRan (PERSIR)-1 study: assessment of current external beam radiotherapy facilities, staff and techniques compared to the international guidelines.

BACKGROUND AND PURPOSE: Radiotherapy (RT) is an essential treatment modality against cancer and becoming even more in demand due to the anticipated increase in cancer incidence. Due to the rapid development of RT technologies amid financial challenges, we aimed to assess the available RT facilities and the issues with achieving health equity based on current equipment compared to the previous reports from Iran. MATERIALS AND METHODS: A survey arranged by the Iran Cancer Institute's Radiation Oncology Research Center (RORC) was sent to all of the country's radiotherapy centers in 2022. Four components were retrieved: the reimbursement type, equipment, human resources, and patient load. To calculate the radiotherapy utilization rate (RUR), the Lancet Commission was used. The findings were compared with the previous national data. RESULTS: Seventy-six active radiotherapy centers with 123 Linear accelerators (LINACs) were identified. The centers have been directed in three ways. 10 (20 LINACs), 36 (50 LINACs), and 30 centers (53 LINACs) were charity-, private-, and public-based, respectively. Four provinces had no centers. There was no active intraoperative radiotherapy machine despite its availability in 4 centers. One orthovoltage X-ray machine was active and 14 brachytherapy devices were treating patients. There were 344, 252, and 419 active radiation oncologists, medical physicists, and radiation therapy technologists, respectively. The ratio of LINAC and radiation oncologists to one million populations was 1.68 and 4.10, respectively. Since 2017, 35±5 radiation oncology residents have been trained each year. CONCLUSION: There has been a notable growth in RT facilities since the previous reports and Iran's situation is currently acceptable among LMICs. However, there is an urgent need to improve the distribution of the RT infrastructure and provide more facilities that can deliver advanced techniques.

Functional Outcomes After Localized Prostate Cancer Treatment.

Importance: Adverse outcomes associated with treatments for localized prostate cancer remain unclear. Objective: To compare rates of adverse functional outcomes between specific treatments for localized prostate cancer. Design, Setting, and Participants: An observational cohort study using data from 5 US Surveillance, Epidemiology, and End Results Program registries. Participants were treated for localized prostate cancer between 2011 and 2012. At baseline, 1877 had favorable-prognosis prostate cancer (defined as cT1-cT2bN0M0, prostate-specific antigen level <20 ng/mL, and grade group 1-2) and 568 had unfavorable-prognosis prostate cancer (defined as cT2cN0M0, prostate-specific antigen level of 20-50 ng/mL, or grade group 3-5). Follow-up data were collected by questionnaire through February 1, 2022. Exposures: Radical prostatectomy (n = 1043), external beam radiotherapy (n = 359), brachytherapy (n = 96), or active surveillance (n = 379) for favorable-prognosis disease and radical prostatectomy (n = 362) or external beam radiotherapy with androgen deprivation therapy (n = 206) for unfavorable-prognosis disease. Main Outcomes and Measures: Outcomes were patient-reported sexual, urinary, bowel, and hormone function measured using the 26-item Expanded Prostate Cancer Index Composite (range, 0-100; 100 = best). Associations of specific therapies with each outcome were estimated and compared at 10 years after treatment, adjusting for corresponding baseline scores, and patient and tumor characteristics. Minimum clinically important differences were 10 to 12 for sexual function, 6 to 9 for urinary incontinence, 5 to 7 for urinary irritation, and 4 to 6 for bowel and hormone function. Results: A total of 2445 patients with localized prostate cancer (median age, 64 years; 14% Black, 8% Hispanic) were included and followed up for a median of 9.5 years. Among 1877 patients with favorable prognosis, radical prostatectomy was associated with worse urinary incontinence (adjusted mean difference, -12.1 [95% CI, -16.2 to -8.0]), but not worse sexual function (adjusted mean difference, -7.2 [95% CI, -12.3 to -2.0]), compared with active surveillance. Among 568 patients with unfavorable prognosis, radical prostatectomy was associated with worse urinary incontinence (adjusted mean difference, -26.6 [95% CI, -35.0 to -18.2]), but not worse sexual function (adjusted mean difference, -1.4 [95% CI, -11.1 to 8.3), compared with external beam radiotherapy with androgen deprivation therapy. Among patients with unfavorable prognosis, external beam radiotherapy with androgen deprivation therapy was associated with worse bowel (adjusted mean difference, -4.9 [95% CI, -9.2 to -0.7]) and hormone (adjusted mean difference, -4.9 [95% CI, -9.5 to -0.3]) function compared with radical prostatectomy. Conclusions and Relevance: Among patients treated for localized prostate cancer, radical prostatectomy was associated with worse urinary incontinence but not worse sexual function at 10-year follow-up compared with radiotherapy or surveillance among people with more favorable prognosis and compared with radiotherapy for those with unfavorable prognosis. Among men with unfavorable-prognosis disease, external beam radiotherapy with androgen deprivation therapy was associated with worse bowel and hormone function at 10-year follow-up compared with radical prostatectomy.

Clinical trials that will change practices: News in palliative radiotherapy.

Palliative radiotherapy is used to alleviate cancer-related symptoms. Symptomatic responses to palliative radiotherapy may however take several weeks, meaning that patients need to survive long enough to derive a real benefit. Oncologists can be optimistic when estimating survival for patients with advanced cancer and as a consequence some patients receiving palliative radiotherapy die before experiencing any gain. Models of patient survival have limited accuracy, particularly for predicting whether patients will die within the next 30 days. Dedicated rapid access palliative radiotherapy clinics, in which patients are assessed, simulated and treated on the same day, reduce the number of patient visits to the radiation oncology department and hence the burden on the patient as well as costs. Teleconsultation and advanced practice nurses can play a crucial role in providing rapid access to palliative radiotherapy in a dedicated palliative radiotherapy service. Single-fraction palliative radiotherapy should be offered to eligible patients if they are able to attend treatment and could potentially benefit from symptom palliation, irrespective of predicted life expectancy. Technical and organizational innovations have been proposed in order to dispense with the computed tomography scanner by carrying out the dosimetry on a recent diagnostic scanner or a magnetic resonance imaging scanner with integrated linear acceleration system. Stereotactic body radiation therapy makes it possible to envisage greater and more lasting analgesic benefits in patients with painful bone metastasis and good prognosis. Flash radiotherapy remains at the preclinical stage.

Biomedical advances and future prospects of high-precision three-dimensional radiotherapy and four-dimensional radiotherapy.

Biomedical advances of external-beam radiotherapy (EBRT) with improvements in physical accuracy are reviewed. High-precision (±1 mm) three-dimensional radiotherapy (3DRT) can utilize respective therapeutic open doors in the tumor control probability curve and in the normal tissue complication probability curve instead of the one single therapeutic window in two-dimensional EBRT. High-precision 3DRT achieved higher tumor control and probable survival rates for patients with small peripheral lung and liver cancers. Four-dimensional radiotherapy (4DRT), which can reduce uncertainties in 3DRT due to organ motion by real-time (every 0.1-1 s) tumor-tracking and immediate (0.1-1 s) irradiation, have achieved reduced adverse effects for prostate and pancreatic tumors near the digestive tract and with similar or better tumor control. Particle beam therapy improved tumor control and probable survival for patients with large liver tumors. The clinical outcomes of locally advanced or multiple tumors located near serial-type organs can theoretically be improved further by integrating the 4DRT concept with particle beams.

Radiotherapy for Primary Pediatric Central Nervous System Malignancies: Current Treatment Paradigms and Future Directions.

BACKGROUND: Central nervous system tumors are the most common solid tumors in childhood. Treatment paradigms for pediatric central nervous system malignancies depend on elements including tumor histology, age of patient, and stage of disease. Radiotherapy is an important modality of treatment for many pediatric central nervous system malignancies. SUMMARY: While radiation contributes to excellent overall survival rates for many patients, radiation also carries significant risks of long-term side effects including neurocognitive decline, hearing loss, growth impairment, neuroendocrine dysfunction, strokes, and secondary malignancies. In recent decades, clinical trials have demonstrated that with better imaging and staging along with more sophisticated radiation planning and treatment set-up verification, smaller treatment volumes can be utilized without decrement in survival. Furthermore, the development of intensity-modulated radiotherapy and proton-beam radiotherapy has greatly improved conformality of radiation. KEY MESSAGES: Recent changes in radiation treatment paradigms have decreased risks of short- and long-term toxicity for common histologies and in different age groups. Future studies will continue to develop novel radiation regimens to improve outcomes in aggressive central nervous system tumors, integrate molecular subtypes to tailor radiation treatment, and decrease radiation-associated toxicity for long-term survivors.

Clinical Care for People Who Survive Childhood Cancer: A Review.

Importance: An estimated 15 000 children and adolescents aged 0 to 19 years are diagnosed with cancer each year in the US, and more than 85% survive for at least 5 years. By 45 years of age, approximately 95% of people who survive childhood cancer will develop a significant health problem related to the childhood cancer diagnosis or its treatment. Observations: Approximately 500 000 people currently alive in the US have survived childhood cancer. The most common severe or life-threatening chronic health problems related to childhood cancer or its treatment are endocrine disorders such as hypothyroidism or growth hormone deficiency (44%), subsequent neoplasms such as breast cancer or thyroid cancer (7%), and cardiovascular disease such as cardiomyopathy or congestive heart failure, coronary artery disease, and cerebrovascular disease (5.3%). Medical conditions related to a cancer diagnosis during childhood or adolescence are most commonly caused by the radiation therapy and the chemotherapies used to treat cancer and may develop at varying lengths of time after exposure to these treatments. Individuals at highest risk for developing treatment-related health problems include patients with brain cancer treated with cranial irradiation (approximately 70% develop severe or life-threatening health problems) and allogeneic hematopoietic stem cell transplant recipients (approximately 60% develop severe or life-threatening health problems). Individuals at the lowest risk for developing treatment-related health problems include those who survived solid tumors (such as Wilms tumor) treated with surgical resection alone or with minimal chemotherapy, for whom the prevalence of subsequent health problems is similar to people who did not have cancer during childhood or adolescence. People diagnosed with childhood cancer in the 1990s who survived for at least 5 years after the cancer diagnosis have a shorter lifespan (by about 9 years) vs children who were not diagnosed with cancer in the 1990s. Conclusions and Relevance: Approximately 500 000 individuals currently alive in the US have survived childhood cancer. The most common adverse effects in individuals who survived childhood cancer are endocrine disorders, subsequent neoplasms, and cardiovascular disease. There is a need for clinicians and patients to have heightened awareness of these complications.

Primer consenso español sobre el uso de la radioterapia intraoperatoria en el cáncer de mama. Conclusiones del panel de expertos / First Spanish consensus on the use of intraoperative radiotherapy in breast cancer. Conclusions of the expert panel

Introducción: la publicación de ensayos aleatorizados con resultados a largo plazo ha demostrado que la radioterapia intraoperatoria (RIO) en cáncer de mama en estadio precoz puede ser una alternativa terapéutica en casos bien seleccionados. En el presente trabajo se presentan los resultados del Primer Consenso de Radioterapia Intraoperatoria en Cáncer de Mama realizado de manera multidisciplinar en España. Material y método: se hizo una revisión sistemática de la literatura y se invitó a todos los oncólogos radioterápicos y cirujanos expertos en RIO en cáncer de mama de España a participar en el consenso. Se aplico la siguiente metodología en 2 fases: a) la creación de un grupo de trabajo y la revisión de la evidencia; b) la realización de la encuesta y generación de recomendaciones consensuadas. Resultados: han participado un total 95,65% de los centros que actualmente utilizan esta técnica en cáncer de mama y que fueron invitados. Los expertos estuvieron de acuerdo en el uso de RIO exclusiva en cáncer de mama en aquellas pacientes mayores de 60 años y por encima de 50 años posmenopáusicas, con carcinoma ductal infiltrante o subtipos histológicos favorables, sin invasión linfovascular, tumores menores o iguales a 25 mm, márgenes de resección libres y receptores hormonales positivos. La utilización de RIO como rescate de recidiva local después de la irradiación externa alcanzó un nivel de consenso muy fuerte. Conclusión: el presente consenso pretende establecer las guías respecto a las indicaciones de RIO exclusiva o como sobreimpresión anticipada y ser una ayuda para la toma conjunta de decisiones. (AU)

Introduction: The publication of randomized trials with long-term results has demonstrated that intraoperative radiation therapy (IORT) in early-stage breast cancer can be a therapeutic alternative for well-selected cases. This paper present work presents the results of the first multidisciplinary consensus on IORT in breast cancer carried out in Spain. Materials and methods: A systematic literature review was conducted, and all radiation oncologists and surgeons with expertise in IORT for breast cancer in Spain were invited to participate in the consensus. The following methodology was employed in two phases: a) creation of a working group and review of the evidence; b) conduct of the survey and generation of consensus recommendations. Results: A total of 95.65% of the invited centers currently utilizing this technique in breast cancer participated. The experts agreed on the use of exclusive intraoperative radiation therapy in breast cancer for patients above 60 years of age and above 50 years postmenopausal, with invasive ductal carcinoma or favorable histological subtypes, no lymphovascular invasion, tumors less than or equal to 25 mm, clear surgical margins, and positive hormone receptor. The use of IORT as salvage surgery for local recurrence after external irradiation achieved a very strong consensus level. Conclusion: The present consensus aims to establish guidelines regarding the indications for exclusive IORT or as an early boost, and to serve as an aid for joint decision-making. (AU)

NTCP Calculations of Five Different Irradiation Techniques for the Treatment of Thymoma.

This study provided normal tissue complication probability (NTCP) calculations from photon radiotherapy techniques in eleven patients with thymoma. Five plans were created for each participant using three-dimensional conformal radiotherapy (3D-CRT), five-field intensity modulated radiotherapy (5F-IMRT), seven-field IMRT (7F-IMRT), and volumetric modulated arc therapy with full arcs (FA-VMAT) and partial arcs (PA-VMAT). The target coverage, homogeneity index and conformation number for the planning target volume (PTV) and dosimetric parameters for the organs-at-risk (OARs) were taken from the fifty-five generated plans. The patient-specific NTCP of the lungs, heart and esophagus was calculated with an in-house software tool using differential dose-volume histograms and the equivalent uniform dose model. The PTV dose metrics from 3D-CRT were inferior to those from IMRT and VMAT plans. The dose constraints for the OARs were met in all treatment plans. The NTCP range of the lungs, heart and esophagus was 0.34-0.49%, 0.03-0.06% and 0.08-0.10%, respectively. The NTCPs of the heart for the incidence of peridarditis from IMRT and VMAT were significantly smaller than those from conformal treatment (p < 0.05). The 7F-IMRT was significantly superior to FA-VMAT in reducing the NTCP of the lungs and the risk of pneumonitis (p = 0.001). Similar superiority of 5F-IMRT over PA-VMAT for lung protection was found (p = 0.009). The presented results may be employed in the selection of the appropriate irradiation technique for restricting the complications in the adjacent OARs.

Consistency of muscle fibers directionality in human thigh derived from diffusion-weighted MRI.

Objective.Diffusion-weighted MR imaging (DW-MRI) is known to quantify muscle fiber directionality and thus may be useful for radiotherapy target definition in sarcomas. Here, we investigate the variability of tissue anisotropy derived from diffusion tensor (DT) in the human thigh to establish the baseline parameters and protocols for DW-MRI acquisition for future studies in sarcoma patients.Approach.We recruited ten healthy volunteers to acquire diffusion-weighted MR images of the left and right thigh. DW-MRI data were used to reconstruct DT eigenvectors within each individual thigh muscle. Deviations of the principal eigenvector from its mean were calculated for different experimental conditions.Main results.Within the majority of muscles in most subjects, the mode of the histogram of the angular deviation of the principal eigenvector of the water DT from its muscle-averaged value did not exceed 20°. On average for all subjects, the mode ranged from 15° to 24°. Deviations much larger than 20° were observed in muscles far from the RF coil, including cases with significant amounts of subcutaneous fat and muscle deformation under its own weight.Significance.Our study is a robust characterization of angular deviations of muscle fiber directionality in the thigh as determined by DW-MRI. We show that an appropriate choice of experimental conditions reduces the variability of the observed directionality. Precise determination of tissue directionality will enable reproducible models of microscopic tumor spread, with future application in defining the clinical target volume for soft tissue sarcoma.

Radiotherapy resources in Brazil (RT2030): a comprehensive analysis and projections for 2030.

BACKGROUND: The demand for radiotherapy in Brazil is unfulfilled, and the scarcity of data on the national network hampers the development of effective policies. We aimed to evaluate the current situation, estimate demands and requirements, and provide an action plan to ensure access to radiotherapy for those in need by 2030. METHODS: The Brazilian Society for Radiation Oncology created a task force (RT2030) including physicians, medical physicists, policy makers, patient advocates, and suppliers, all of whom were major stakeholders involved in Brazilian radiotherapy care. The group was further divided into seven working groups to address themes associated with radiotherapy care in Brazil. From March 1, 2019, to Aug 3, 2020, there were monthly meetings between the group's leaders and the Central Committee and six general meetings. First, a comprehensive search of all different national databases was done to identify all radiotherapy centres. Questionnaires evaluating radiotherapy infrastructure and human resources and assing the availability, distribution, capacity, and workload of resources were created and sent to the radioprotection supervisor of each centre. Results were analysed nationally and across the country's regions and health-care systems. A pre-planned review of available databases was done to gather data on active radiation oncology centres and the distribution of radiotherapy machines (linear accelerators [LINACs]) across Brazil. We used national population and cancer incidence projections, recommended radiotherapy usage from the medical literature, and national working patterns to project radiotherapy demands in 2030. An action plan was established with suggestions to address the gaps and meet the demands. FINDINGS: The database search yielded 279 centres with an active radiotherapy registry. After applying predefined exclusion criteria, 263 centres were identified that provided external beam radiotherapy machines with or without brachytherapy. All 263 operational centres answered the questionnaires sent on Dec 9, 2019, which were then returned between Jan 1 and June 30, 2020. There were 409 therapy machines, 646 radiation oncologists, 533 physicists, and 230 989 patients undergoing radiotherapy (150 628 [65·2%] in the public health-care system and 80 937 [35·0%] in private). The mean annual occupation rate was 566 patients per treatment machine (SD 250). The number of residents per treatment machine ranged from 258 333 to 1 800 000. Technology availability varied considerably among regions and systems. In 2030, 639 994 new cancer cases are expected, which will require 332 797 radiotherapy courses. Therefore, 530 LINACs, 1079 radiation oncologists, and 1060 medical physicists will be needed. INTERPRETATION: The expected increase in cancer incidence in the coming years will probably increase the disparities in cancer care and the burden for Brazilian patients. We provide a roadmap of the current situation and the particularities of the Brazilian radiotherapy network, which can serve as a starting point for cancer policy planning to improve this scenario. FUNDING: Accuray, BRAINLAB, Elekta, IBA, ONE medical solution, SUN NUCLEAR corporation, VARIAN, and ZIGMA.

Radio-immune response modelling for spatially fractionated radiotherapy.

Objective.Radiation-induced cell death is a complex process influenced by physical, chemical and biological phenomena. Although consensus on the nature and the mechanism of the bystander effect were not yet made, the immune process presumably plays an important role in many aspects of the radiotherapy including the bystander effect. A mathematical model of immune response during and after radiation therapy is presented.Approach.Immune response of host body and immune suppression of tumor cells are modelled with four compartments in this study; viable tumor cells, T cell lymphocytes, immune triggering cells, and doomed cells. The growth of tumor was analyzed in two distinctive modes of tumor status (immune limited and immune escape) and its bifurcation condition.Main results.Tumors in the immune limited mode can grow only up to a finite size, named as terminal tumor volume analytically calculated from the model. The dynamics of the tumor growth in the immune escape mode is much more complex than the tumors in the immune limited mode especially when the status of tumor is close to the bifurcation condition. Radiation can kill tumor cells not only by radiation damage but also by boosting immune reaction.Significance.The model demonstrated that the highly heterogeneous dose distribution in spatially fractionated radiotherapy (SFRT) can make a drastic difference in tumor cell killing compared to the homogeneous dose distribution. SFRT cannot only enhance but also moderate the cell killing depending on the immune response triggered by many factors such as dose prescription parameters, tumor volume at the time of treatment and tumor characteristics. The model was applied to the lifted data of 67NR tumors on mice and a sarcoma patient treated multiple times over 1200 days for the treatment of tumor recurrence as a demonstration.

Radiotherapy Infrastructure Shielding Calculations: software development for shielding calculations in a linear accelerator radiotherapy room.

This work aimed to develop and validate software that calculates the shielding thickness required for a radiotherapy room with a linear accelerator utilising geometric and dosimetric data. The software "Radiotherapy Infrastructure Shielding Calculations" (RISC) was developed using MATLAB programming. It does not require the installation of the MATLAB platform, and the user only needs to download and install the application, which displays a graphical user interface (GUI). The GUI includes empty cells to insert numerical values for several parameters to calculate the proper shielding thickness. The GUI comprises two main interfaces, one for the primary and one for the secondary barrier calculation. The interface of the primary barrier is divided into four tabs: (a) primary radiation, (b) patient scattered and leakage radiation, (c) IMRT techniques and (d) the shielding cost calculations. The interface of the secondary barrier includes three tabs: (a) patient scattered and leakage radiation, (b) IMRT techniques and (c) the shielding cost calculations. Each tab consists of two sections: one for input and one for output of the necessary data. The RISC is based on the methods and formulae of the NCRP 151 and calculates the primary and secondary barrier thickness for ordinary concrete with a density of 2.35 g/cm3 and the cost for a radiotherapy room with a linear accelerator that performs conventional or IMRT techniques. Calculations can be performed for photon energies of 4, 6, 10, 15, 18, 20, 25 and 30 MV of a dual-energy linear accelerator, while instantaneous dose rate (IDR) calculations are also performed. The RISC has been validated using all comparative examples of NCRP 151 and the calculations from shielding reports of the Varian IX linear accelerator at Methodist Hospital of Willowbrook and Elekta Infinity at the University Hospital of Patras. The RISC is accompanied by two text files: (a) "Terminology," extensively describing all parameters, and (b) "User's Manual," providing useful instructions to the user. The RISC is user-friendly, simple, fast and precise, providing accurate shielding calculations and quickly and easily reproducing different shielding scenarios for a radiotherapy room with a linear accelerator. Additionally, it could be used during the educational process of shielding calculations by graduate students or trainee medical physicists. As a future work, the RISC will be updated with new features such as skyshine radiation, door shielding, and other types of machines and shielding materials.