Therapeutic Applications of Monte Carlo Calculations in Nuclear Medicine

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135088/1/mp3742.pd

Electromagnetic dissociation of Co and Au targets by a 10.2 GeV/nucleon Au beam

Collisions of relativistic heavy ions (RHI) can be broadly categorized as two types: central (nuclear force dominated) and peripheral (coulomb force dominated). The experiment described addresses the latter. Unlike the neutron removal cross section via the nuclear force [sigma]nucl, the neutron removal cross section via the coulomb force [sigma]coul is an increasing function of energy due to the Lorentz contraction of the electromagnetic fields. As more energetic and heavier (higher Z) RHI beams have become available, there appears to be an overestimation of the one neutron removal cross section by the virtual photon theoretical treatment of Wiezsacker, Williams and Fermi (WWF). An experiment was performed at the AGS at BNL using a 10.2 GeV/nucleon Au beam in order to determine the behavior of the phenomena referred to as Electromagnetic Dissociation (ED). Au and Co targets were irradiated after which, the yield of one and two neutron removal from Au and Co along with other isotopes was determined using gamma ray spectroscopy;In addition, a testing program to evaluate the performance of a group of custom made circuit boards for use in the Late Energy Trigger (LET) in a strange matter search experiment (E864) will be described

Feasibility of tomotherapy-based image-guided radiotherapy for small cell lung cancer

Background: To assess the tolerance of patients with small cell lung cancer undergoing chemoradiation with tomotherapy-based image-guided radiotherapy (IGRT). Materials and Methods: A retrospective review of the toxicity profile for nine patients with small cell lung cancer of the limited stage who underwent chemoradiation delivered with helical tomotherapy (HT) has been conducted. Results: Acute grade 3–4 hematologic and esophagitis toxicities developed in two and three patients respectively. One patient developed a pulmonary embolism during radiotherapy. Seven patients had weight loss ranging from 0 to 30 pounds (median: 4 pounds). Three patients had treatment breaks ranging from 2 to 12 days. At a median follow-up of 11 months (range: 2–24 months), no patients developed any radiation related toxicities such as grade 3–4 pneumonitis or other long-term complications. The median survival was estimated to be 15 months. There were two local recurrences, three mediastinal recurrences, and six distant metastases. Conclusion: Grade 3–4 toxicities remained significant during chemoradiation when radiation was delivered with tomotherapy-based IGRT. However, the absence of grade 3–4 pneumonitis is promising and the use of HT needs to be investigated in future prospective studies

Phenomenology of the deuteron electromagnetic form factors

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data

Electromagnetic dissociation of Co and Au targets by a 10.2 GeV/nucleon Au beam

Collisions of relativistic heavy ions (RHI) can be broadly categorized as two types: central (nuclear force dominated) and peripheral (coulomb force dominated). The experiment described addresses the latter. Unlike the neutron removal cross section via the nuclear force [sigma]nucl, the neutron removal cross section via the coulomb force [sigma]coul is an increasing function of energy due to the Lorentz contraction of the electromagnetic fields. As more energetic and heavier (higher Z) RHI beams have become available, there appears to be an overestimation of the one neutron removal cross section by the virtual photon theoretical treatment of Wiezsacker, Williams and Fermi (WWF). An experiment was performed at the AGS at BNL using a 10.2 GeV/nucleon Au beam in order to determine the behavior of the phenomena referred to as Electromagnetic Dissociation (ED). Au and Co targets were irradiated after which, the yield of one and two neutron removal from Au and Co along with other isotopes was determined using gamma ray spectroscopy;In addition, a testing program to evaluate the performance of a group of custom made circuit boards for use in the Late Energy Trigger (LET) in a strange matter search experiment (E864) will be described.</p

Effectiveness of prophylactic retropharyngeal lymph node irradiation in patients with locally advanced head and neck cancer

BACKGROUND:The aim of the study is to assess the effectiveness of intensity-modulated radiotherapy (IMRT) or image-guided radiotherapy (IGRT) for the prevention of retropharyngeal nodal recurrences in locally advanced head and neck cancer.METHODS:A retrospective review of 76 patients with head and neck cancer undergoing concurrent chemoradiation or postoperative radiotherapy with IMRT or IGRT who were at risk for retropharyngeal nodal recurrences because of anatomic site (hypopharynx, nasopharynx, oropharynx) and/or the presence of nodal metastases was undertaken.The prevalence of retropharyngeal nodal recurrences was assessed on follow-up positron emission tomography (PET)-CT scans.RESULTS:At a median follow-up of 22months (4-53months), no patient developed retropharyngeal nodal recurrences.CONCLUSION:Prophylactic irradiation of retropharyngeal lymph nodes with IMRT or IGRT provides effective regional control for individuals at risk for recurrence in these nodes.This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at [email protected]

Effectiveness of prophylactic retropharyngeal lymph node irradiation in patients with locally advanced head and neck cancer

Abstract Background The aim of the study is to assess the effectiveness of intensity-modulated radiotherapy (IMRT) or image-guided radiotherapy (IGRT) for the prevention of retropharyngeal nodal recurrences in locally advanced head and neck cancer. Methods A retrospective review of 76 patients with head and neck cancer undergoing concurrent chemoradiation or postoperative radiotherapy with IMRT or IGRT who were at risk for retropharyngeal nodal recurrences because of anatomic site (hypopharynx, nasopharynx, oropharynx) and/or the presence of nodal metastases was undertaken. The prevalence of retropharyngeal nodal recurrences was assessed on follow-up positron emission tomography (PET)-CT scans. Results At a median follow-up of 22 months (4–53 months), no patient developed retropharyngeal nodal recurrences. Conclusion Prophylactic irradiation of retropharyngeal lymph nodes with IMRT or IGRT provides effective regional control for individuals at risk for recurrence in these nodes.</p

Feasibility of image-guided radiotherapy based on tomotherapy for the treatment of locally advanced anal carcinoma

The standard of care for locally advanced anal cancer has been concurrent chemoradiation. However, conventional treatment with 3-dimensional radiotherapy is associated with significant toxicity. The feasibility of new radiotherapy techniques such as image-guided radiotherapy (IGRT) in combination with chemotherapy for the treatment of this malignancy was assessed

Effectiveness of image-guided radiotherapy for laryngeal sparing in head and neck cancer

We would like to compare the effectiveness of image-guided (IGRT) and intensity-modulated (IMRT) radiotherapy to spare the larynx in head and neck cancer patients. A retrospective review of 48 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers. Mean laryngeal and hypopharyngeal dose was compared between 11 patients treated with IMRT and 37 patients treated with IGRT. Mean laryngeal dose was, respectively, 41.2 Gy and 22.8 Gy for the IMRT and IGRT technique (p<0.001). The radiation dose to the middle and inferior pharyngeal muscles was also significantly reduced with the IGRT technique. Mean pharyngeal dose was, respectively, 52 Gy and 26 Gy for the IMRT and IGRT technique (p=0.0001). Laryngeal sparing IGRT technique for head and neck cancer minimizes radiotherapy dose to the larynx and pharynx without sacrificing target coverage, even in the presence of neck lymph nodes