Radiation Therapy Techniques and Applications

External Beam Radiation Therapy (EBRT)

The European Society for Radiotherapy and Oncology recommends Three-Dimensional Conformal Radiation Therapy (3D-CRT) for precise radiation delivery, using photon energy equal or superior to 10 MV 1, 2
Intensity Modulated Radiation Therapy (IMRT) is an advanced form of 3D-CRT that uses inverse treatment planning with beams from different angles, shaped according to the target form, with intensity adjusted throughout treatment to optimize dose to the target while limiting dose to surrounding normal tissues 2, 3, 4
Volumetric Modulated Arc Therapy (VMAT) is a form of IMRT where the radiation source rotates around the patient in one or more arcs while continuously delivering radiation 2, 4
Stereotactic Body Radiation Therapy (SBRT)/Stereotactic Ablative Radiotherapy (SABR) uses focused beams of high-dose radiation, typically 6-18 Gy, delivered in fewer sessions, usually 2-8, compared to conventional radiotherapy, achieving high biological effectiveness while sparing surrounding tissues 2, 3

Low Dose Rate (LDR) Brachytherapy delivers radiation at a low dose rate over time, with radioactive sources placed permanently or temporarily in the body 1, 5
High Dose Rate (HDR) Brachytherapy delivers higher doses of radiation in a shorter time period using temporarily placed radioactive sources 1
Endocavitary Brachytherapy involves placing radiation sources in body cavities near the tumor, commonly used in cervical cancer 1
Interstitial Brachytherapy involves placing radiation sources directly into the tumor tissue 1

Adaptive Radiation Therapy modifies the treatment plan during the course of treatment based on changes in tumor size, shape, or position 2
Transarterial Radioembolization (TARE) delivers radioactive microspheres through the hepatic artery to treat liver tumors, according to the American College of Radiology 6, 7

For lung cancer, the American College of Radiology recommends SBRT for early-stage non-small cell lung cancer (NSCLC) in inoperable patients, and IMRT with concurrent or sequential chemotherapy for locally advanced NSCLC 2, 3, 4
For prostate cancer, the American Urological Association recommends options including EBRT, brachytherapy alone, or combination therapy depending on risk stratification, with IMRT commonly used to minimize urinary and rectal toxicity 5, 8
For liver cancer, the European Association for the Study of the Liver recommends SBRT for early-stage disease or oligometastases 7
For cervical cancer, the International Commission of Radiation Units recommends a combination of external beam radiotherapy and brachytherapy, with standard dosimetry according to their guidelines 1

The British Journal of Cancer reports that VMAT provides superior high-dose sparing but increases low-dose bath to normal tissues, which is a critical distinction in treatment planning 9, 10, 11, 12
For lung cancer, VMAT decreases V20 dosimetric values to non-target lung, which is the primary predictor of fatal pneumonitis, as reported by the British Journal of Cancer 9, 10, 11
The Journal of Clinical Oncology recommends that when comparing IMRT delivery techniques, rotational or arc-based delivery techniques such as tomotherapy and VMAT show incremental improvement in target coverage and avoidance of organs at risk 13, 14, 15
The Journal of Clinical Oncology suggests choosing VMAT when high-dose organ sparing is the priority, treatment efficiency is important, or contralateral lung sparing is critical, with standard dosimetric guidelines for organs at risk used as established predictors of radiation toxicity 13, 14, 15
The experience of a center with a given technique is most relevant with these complex treatment modalities, as noted by the Journal of Clinical Oncology 13, 14, 15

The National Comprehensive Cancer Network recommends standardized nomenclature for planning target volume (PTV), clinical target volume (CTV), and gross tumor volume (GTV) for radiation oncology treatment planning 16
The International Commission on Radiation Units and Measurements provides guidance on dose prescription, reporting, and recording for intensity-modulated radiation therapy (IMRT) techniques, including dose reporting parameters such as D98, D95, D50, D2, and homogeneity index 16, 17

The National Comprehensive Cancer Network guidelines for Hodgkin lymphoma cite ICRU 83 for dose prescription, reporting, and recording, emphasizing the importance of standardized protocols in radiation oncology 16
The National Comprehensive Cancer Network guidelines for malignant pleural mesothelioma recommend ICRU 83 for clinical target volume definition, highlighting the need for precise target delineation in radiation therapy 17
The National Comprehensive Cancer Network guidelines for head and neck cancer reference ICRU 83 principles for target delineation, underscoring the importance of accurate target definition in intensity-modulated radiation therapy (IMRT) 18, 19, 20
The European Association of Urology guidelines for prostate cancer utilize ICRU 83 criteria for plan evaluation, demonstrating the applicability of ICRU 83 standards to various tumor sites 21