Analysis of COVID-19 pandemic in USA, using Topological Weighted Centroid.

The first case of COVID-19 in USA was reported on January 20, 2020. The number of COVID-19 confirmed cases and death has increased since the first reported case and the outbreak has appeared in all states. This paper analyzes disease outbreak using Topological Weighted Centroid (TWC), which is a data driven intelligent geographical dynamical system that models disease spread in space and time.

Left-sided breast cancer irradiation using rotational and fixed-field radiotherapy.

The 3-dimensional conformal radiotherapy (3DCRT) technique is the standard for breast cancer radiotherapy. During treatment planning, not only the coverage of the planning target volume (PTV) but also the minimization of the dose to critical structures, such as the lung, heart, and contralateral breast tissue, need to be considered. Because of the complexity and variations of patient anatomy, more advanced radiotherapy techniques are sometimes desired to better meet the planning goals.

Esophageal cancer patients undergoing external beam radiation after placement of self-expandable metal stents: is there a risk of radiation dose enhancement?

Background: Self-expandable metal stents (SEMSs) are used for palliation of malignant dysphagia. It is not known whether dose adjustments are required when there is a stent in the radiation field.

Objective: To measure the effects of esophageal stents of various designs and materials on radiation dose to the tissue adjacent to the stent in the radiation field to determine whether there should be any dose adjustment.

Respiration induced heart motion and indications of gated delivery for left-sided breast irradiation.

Purpose: To investigate respiration-induced heart motion for left-sided breast irradiation using a four-dimensional computed tomography (4DCT) technique and to determine novel indications to assess heart motion and identify breast patients who may benefit from a gated treatment.

Methods And Materials: Images of 4DCT acquired during free breathing for 20 left-sided breast cancer patients, who underwent whole breast irradiation with or without regional nodal irradiation, were analyzed retrospectively. Dose distributions were reconstructed in the phases of 0%, 20%, and 50%.

Improved survival in patients with early stage low-grade follicular lymphoma treated with radiation: a Surveillance, Epidemiology, and End Results database analysis.

Background: External beam radiation therapy (RT) is the standard treatment for stage I-II, grade 1-2 follicular lymphoma. Because of an indolent natural history, some advocate alternative management strategies, including watchful waiting for this disease. The relative improvement in outcomes for patients treated with and without RT has never been tested in randomized trials.

Supine craniospinal irradiation setup with two spine fields.

Craniospinal irradiation is an integral part of treatment for a number of cancers. Typically, patients are positioned prone, which allows visualization of field matches. However, a supine position allows better airway access for patients requiring anesthesia, and is more comfortable for patients.

Cardiac mortality in patients with stage I and II diffuse large B-cell lymphoma treated with and without radiation: a surveillance, epidemiology, and end-results analysis.

Purpose: Standard therapy for stage I and II diffuse large B-cell lymphoma consists of combined modality therapy with anthracycline-based chemotherapy, anti-CD20 antibody, and radiation therapy (RT). Curative approaches without RT typically utilize more intensive and/or protracted chemotherapy schedules. Anthracycline-based chemotherapy regimens are associated with a dose-dependent risk of left ventricular systolic dysfunction.

Toxicity assessment of pelvic intensity-modulated radiotherapy with hypofractionated simultaneous integrated boost to prostate for intermediate- and high-risk prostate cancer.

Purpose: To evaluate the toxicity of pelvic intensity-modulated radiotherapy (IMRT) with hypofractionated simultaneous integrated boost (SIB) to the prostate for patients with intermediate- to high-risk prostate cancer.

Methods And Materials: A retrospective toxicity analysis was performed in 30 consecutive patients treated definitively with pelvic SIB-IMRT, all of whom also received androgen suppression. The IMRT plans were designed to deliver 70 Gy in 28 fractions (2.

Dosimetric comparison between 3DCRT and IMRT using different multileaf collimators in the treatment of brain tumors.

We investigated the differences between 3-dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT), and the impact of collimator leaf-width on IMRT plans for the treatment of nonspherical brain tumors. Eight patients treated by 3DCRT with Novalis were selected. We developed 3 IMRT plans with different multileaf collimators (Novalis m3, Varian MLC-120, and Varian MLC-80) with the same treatment margins, number of beams, and gantry positions as in the 3DCRT treatment plans.

Outcomes and effect of radiotherapy in patients with stage I or II diffuse large B-cell lymphoma: a surveillance, epidemiology, and end results analysis.

Purpose: To assess disease-specific survival (DSS), overall survival (OS), and the effect of radiotherapy (RT) in patients with localized diffuse large B-cell lymphoma (DLBCL).

Patients And Methods: The Surveillance, Epidemiology, and End Results database was queried for all patients diagnosed with Stage I, IE, II, or IIE DLBCL between 1988 and 2004. The analyzable data included gender, age, race, stage, presence of extranodal disease, and RT administration.

An optimization model and solution for radiation shielding design of radiotherapy treatment vaults.

In radiation shielding design, one is usually faced with a set of conflicting goals that are navigated by an experienced physicist. If one has abundant space, the task is simplified because concrete is relatively inexpensive and will provide adequate shielding for high energy photons and neutrons, when applicable. However, if space is constrained (which is usually the case), the design becomes more difficult since one will likely have to employ combinations of steel, lead, and concrete, or other new materials--each with different properties and costs.

Visual sensations during megavoltage radiotherapy to the orbit attributable to Cherenkov radiation.

During megavoltage photon and electron beam radiotherapy treatment involving the eye, patients commonly report visual sensations; "nerve stimulation" is the conventional explanation. We propose that the phenomenon can be attributed to Cherenkov radiation inside the eye. The threshold electron energy for Cherenkov radiation in water is 260 keV.

Evaluation of breast sentinel lymph node coverage by standard radiation therapy fields.

Background: Biopsy of the breast sentinel lymph node (SLN) is now a standard staging procedure for early-stage invasive breast cancer. The anatomic location of the breast SLN and its relationship to standard radiation fields has not been described.

Methods And Materials: A retrospective review of radiotherapy treatment planning data sets was performed in patients with breast cancer who had undergone SLN biopsy, and those with a surgical clip at the SLN biopsy site were identified.

The dosimetric effect of inhomogeneity correction in dynamic conformal arc stereotactic body radiation therapy for lung tumors.

For patients treated with lung stereotactic body radiation therapy (SBRT) using dynamic conformal arcs, the influence of inhomogeneity correction (IC) on normal tissue and tumor dosimetry was studied. For the same numbers of monitor units, the planning target volume equivalent uniform doses calculated without path-length IC were lower than those calculated with IC (mean difference 18%, range 1-34%; p < 0.0001).

New radiation therapy techniques for the treatment of head and neck cancer.

This article reviews the most recent technology used in the treatment of head and neck cancer. It discusses brachytherapy, new ways to mix radionuclides for enhanced radiobiologic effects, and different fractionation schemes that have grown in clinical importance. Intensity-modulated radiotherapy has become a mainstay in head and neck cancer treatment, and the authors discuss several popular and emerging approaches.

Clinical application of intensity-modulated radiotherapy for locally advanced cervical cancer.

Intensity-modulated radiotherapy (IMRT) offers technical advantages over conventional external beam radiotherapy (CXRT) that might prove clinically advantageous in the management of gynecologic malignancies. Especially in the case of locally advanced cervical cancer, IMRT provides an opportunity to improve the therapeutic ratio by allowing a selective combination of normal tissue dose reduction and/or concomitant integrated boost dose to the tumor. The clinical and biologic rationale for IMRT in this setting is presented here, and pertinent technical considerations such as the delineation of relevant clinical and planning target volumes are discussed.

Technical considerations in the application of intensity-modulated radiotherapy as a concomitant integrated boost for locally-advanced cervix cancer.

The technical aspects of IMRT applied to cervix cancer are discussed in this paper, as well as issues related to tumor delineation, target volume definitions, inverse planning, and IMRT delivery. A theoretical example illustrating how IMRT can accurately mimic dose distributions obtained using conventional planning plus HDR brachytherapy is also shown. The notion of clinical optimization parameters is introduced to account for the radiation delivery variables, which affect the overall treatment time.