Technological Advancements in External Beam Radiation Therapy (EBRT): An Indispensable Tool for Cancer Treatment

Figures & data

Table 1 Different Types of External Beam Radiation Therapy (EBRT) Techniques and Associated Advantages and Disadvantages

S.No.	External Beam Radiation Therapy (EBRT) Technology	Types of Cancer Treated	Advantages	Disadvantages
1.	3 dimensional conformal radiotherapy (3DCRT)	Brain tumors, breast cancer, gastrointestinal (GI) cancer, lung cancer and gynecologic malignancies.	Improve short-term response rate, reduce mouth dryness and parotid gland injury, and promote the prognosis of patients with nasopharyngeal carcinoma.	Shows higher gastrointestinal toxicities in patients with endometrial cancers. Difficult to perform correct quality procedures, positioning, imaging, contouring, dosimetry, follow-up, and dose delivery
2.	Intensity modulated radiotherapy (IMRT)	Head and neck, prostate, breast, lung, brain, gynecologic, and GI cancers.	Provides high conformity and high precision.	IMRT is prone to geometrical errors, due to higher dose conformity indices.
3.	Volumetric modulated arc therapy (VMAT)	Head and neck, non-small cell lung cancer (NSCLC), prostate, gastrointestinal, gynecological, thoracic, central nervous system, and breast tumors	Provides a full 360° of beam directions with the entire dose volume delivered in a single rotation VMAT treatment shows a lower risk of OAR irradiation and has better homogeneity compared to IMRT. Significant role in uncomfortable immobilization.	Increase in the low dose radiation to the surrounding tissues and organs, with a greater chance of having secondary malignancies.
4.	Image guided radiotherapy (IGRT)	Prostate, lung and head and neck cancers	Significant reduction in set-up margins resulting in reduced toxicities in sites with demonstrable, quantifiable, and correctable inter- and/ or intra- fraction motion	Uncertainties in target volume delineation, image quality, longer acquisition times, high intra-fractional errors, and extra-dose delivery during daily imaging
5.	Stereotactic body radiation therapy (SBRT)	Prostate, head and neck, spinal, renal, oligo metastases, and pancreatic	Provides high doses of radiation to the tumor and has low risk of postoperative risk and death.	Post treatment side-effects.
6.	Particle therapy Proton Neutron Carbon	Stage II–III NSCLC, prostate carcinoma, chordoma and hepatocellular carcinoma etc.	Particle radiation has a higher biological effectiveness and is very effective in radio-resistant cancers.	The production of particle radiation therapy is much more expensive than the production of photons, and has more logistical requirements
7.	Photodynamic therapy (PDT)	Esophageal, non-small cell lung cancer and Barrett's esophagus patients	PDT specifically accumulates into tumors and uses intense non-thermal visible light source.	Success of PDT is limited by uptake and localization of the photosensitizer, the method of light delivery, spatio-temporal organization and location of tumors, singlet and triplet quantum yields, and associated side-effects

Scheme 1 IRaGAZ (Ionizing radiation + Gold nanoparticles + Azido-2-DG).

Note: A novel three stage nanotechnology- chemo-radiation combinatorial approach in enhancing therapeutic efficacy.