The efficacy of conventional external beam, three-dimensional conformal, intensity-modulated, particle beam radiation, and brachytherapy for localized prostate cancer

Abstract

Technologic advances in radiation treatment planning and delivery have generated popular interest in the different radiation therapy techniques used in treating patients with localized prostate cancer. Throughout the past decade, high-energy (> 4 MV) linear accelerators have largely replaced Cobalt machines in external beam radiation therapy (EBRT) delivery. Conventional EBRT has been used to treat prostate cancer successfully since the 1950s. By switching to computed tomography-based planning, three-dimensional conformal radiation therapy provides better relative conformality of dose than does conventional EBRT. Intensity-modulated radiation therapy (IMRT) has further refined dose conformality by spreading the low-dose region to a larger volume. However, the potential long-term risks of larger volumes of normal tissues receiving low doses of radiation in IMRT are unknown. Particle-beam radiation therapy offers unique dose distributions and characteristics with higher relative biologic effect and linear energy transfer. Transperineal prostate brachytherapy offers the shortest treatment time with equivalent efficacy without significant risk of radiation exposure. The addition of hormonal therapy to radiation therapy has been shown to improve the outcome of radiation therapy.

Nanomaterials for Radiation Therapy

“…Brachytherapy is a subcategory of radiation therapy in which one or more radioactive seeds are physically inserted into the patient to make contact with the tumor for a given amount of time, depending on the prescription dose and source activity. Because of the geometrical proximity and the utilization of less -penetrating lowerenergy γ -rays or β -particles in brachytherapy, the radiation dose is generally more conformal to the tumor [93] . Brachytherapy has gained wide application in the treatment of prostate, cervical, and other type of cancers [94] .…”

Residual Translational and Rotational Errors after kV X-Ray Image-Guided Correction of Prostate Location Using Implanted Fiducials

“…Other methods to align the patient are based on ultrasound localizations [30], electronic portal imaging or Xray imaging of implanted markers [8,11] or megavoltage CT ± FMs [16,20,39]. The authors describe displacements in the same range as in [13], i.e., especially random errors up to 5 mm.…”

“…Intensity-modulated radiation therapy (IMRT) of prostate cancer [8] leads to steep dose gradients between the planning target volume (PTV) and adjacent organs [35], which imply the risk of over-or underdosing structures on a small-volume scale [42]. Delivery of high doses to the PTV is especially complicated by prostate movement relative to the pelvic bones and skin alignment marks [47] and motivates the concept of image-guided radiotherapy (IGRT).…”

Interstitial Brachytherapy Guided Intensity Modulated Radiation Therapy in Cervical Carcinoma: A Dosimetric Study

“…On the contrary, IMRT has many attractive features making it convenient to both patients and physicians. Considering the increasing popularity of IMRT and emerging data on BT-IMRT comparison in various sites like breast [ 18 , 19 ] and prostate [ 20 ], IBT in cervix is likely to face, sooner or later, a stiff challenge. Both techniques have good potentials and we believe in their complementary use rather than substitute of each other.…”