Whole-body diffusion-weighted MRI and (18)F-FDG PET/CT can discriminate between different lymphoma subtypes

Can 18F-FDG PET/CT findings be used to predict orbital tumor histology?

PURPOSE

To investigate whether 18F-FDG PET/CT might be useful to predict the histology of various orbital tumors based on the maximum standard uptake value (SUVmax) and the OMSUV (orbital max SUV)/MLSUV (mean liver SUV) ratio.

PATIENTS AND METHODS

A retrospective single-center study was conducted between May 2019 and December 2020. Patients with an orbital mass who underwent preoperative 18F-FDG PET/CT followed by an orbital biopsy were included. Tumor histology was classified as follows: orbital inflammation, solid tumor, low-grade lymphoid tumor, and high-grade lymphoid tumor. Orbital tumors were also classified as indolent or aggressive. Data recorded included the orbital SUVmax, OMSUV/MLSUV ratio and additional extra-orbital SUV sites.

RESULTS

Forty-five patients (24 men) were included. There were 15 (33.3%), 14 (31.1%), 9 (20%), and 7 (15.5%) cases of orbital inflammation, solid tumor, low-grade lymphoid tumor, and high-grade lymphoid tumor, respectively. No correlation was found between the OMSUV/MLSUV ratio and orbital SUVmax and tumor histology (Z = -0.77, Z = -0.6, Z = -1.6, and Z = 0.94, all P > 0.05, respectively). No correlation was found between the OMSUV/MLSUV ratio (Z = -1.42, P > 0.05) and orbital SUVmax (Z = -0.82, P > 0.05) and tumor aggressiveness (indolent versus aggressive). Subgroup analyses showed that SUVmax was predictive of lymphoma aggressiveness (P = 0.05) and was able to distinguish orbital cancers (all lymphomas+solid tumors) from benign tumors (P = 0.02).

CONCLUSION

18F-FDG PET/CT could not be used to predict the underlying orbital tumor histology. However, more aggressive tumors, especially high-grade lymphomas and cancers, tended to have a higher orbital SUVmax compared to indolent lesions.

Diffusion-weighted Imaging of the Chest: A Primer for Radiologists

Diffusion-weighted imaging (DWI) is a fundamental sequence not only in neuroimaging but also in oncologic imaging and has emerging applications for MRI evaluation of the chest. DWI can be used in clinical practice to enhance lesion conspicuity, tissue characterization, and treatment response. While the spatial resolution of DWI is in the order of millimeters, changes in diffusion can be measured on the micrometer scale. As such, DWI sequences can provide important functional information to MRI evaluation of the chest but require careful optimization of acquisition parameters, notably selection of b values, application of parallel imaging, fat saturation, and motion correction techniques. Along with assessment of morphologic and other functional features, evaluation of DWI signal attenuation and apparent diffusion coefficient maps can aid in tissue characterization. DWI is a noninvasive noncontrast acquisition with an inherent quantitative nature and excellent reproducibility. The outstanding contrast-to-noise ratio provided by DWI can be used to improve detection of pulmonary, mediastinal, and pleural lesions, to identify the benign nature of complex cysts, to characterize the solid portions of cystic lesions, and to classify chest lesions as benign or malignant. DWI has several advantages over fluorine 18 (18F)-fluorodeoxyglucose PET/CT in the assessment, TNM staging, and treatment monitoring of lung cancer and other thoracic neoplasms with conventional or more recently developed therapies. © RSNA, 2023 Quiz questions for this article are available in the supplemental material. Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

The potential application of MR-derived ADCmin values from 68Ga-DOTATATE and 18F-FDG dual tracer PET/MR as replacements for FDG PET in assessment of grade and stage of pancreatic neuroendocrine tumors

BACKGROUND

To evaluate the utility of ⁶⁸Ga-DOTATATE and ¹⁸F-FDG PET/MR for prediction of grade and stage of pancreatic neuroendocrine tumors (PNETs), and to examine the correlation between parameters obtained from FDG PET and diffusion-weighted imaging (DWI) MR parameters.

METHODS

A retrospective study using ⁶⁸Ga-DOTATATE and ¹⁸F-FDG PET/MR imaging was performed between April 2020 and May 2022 on 46 individuals with histologically confirmed PNETs. Metabolic tumor volume (MTV), maximum standardized uptake value (FSUVmax), and tumor lesion glycolysis (TLG) for FDG; somatostatin receptor density (SRD), maximum standardized uptake value (GSUVmax), and total lesion somatostatin receptor density (TLSRD) for DOTATATE; and minimum and mean apparent diffusion coefficient (ADCmin and ADCmean) values for MRI, respectively. We performed Spearman's correlation analysis to examine the links between these variables and primary tumor stage and grading.

RESULTS

Higher PNET grading was associated with higher FSUVmax, MTV, and TLG values (P < 0.05). TLG, SRD, ADCmin, and ADCmean values were correlated with N staging, while SRD, MTV, ADCmin, TLG, and ADCmean were associated with M staging. Notably, ADCmin was a negative correlation between FSUVmax (r =  - 0.52; P < 0.001), MTV (r =  - 0.50; P < 0.001), and TLG (r =  - 0.56; P < 0.001).

CONCLUSIONS

This study highlights significant correlative relationships between FDG PET-derived parameters and ADCmin. ADCmin may offer utility as a tool for PNET staging and grading in lieu of FDG PET. ⁶⁸Ga-DOTATATE PET/MR alone may be a sufficient alternative to dual tracer PET/MR when conducting grading and staging of primary PNETs.

Diagnostic Value of Magnetic Resonance Diffusion-Weighted Imaging Combined with Routine Scanning in Body Tumors

The aim of this study was to evaluate the value of whole body magnetic resonance diffusion-weighted imaging (WB-DWI) combined with routine scanning in the diagnosis of body tumors. Sixty-three patients with surgically and pathologically confirmed body tumors admitted to our hospital from October 2019 to October 2021 were scanned by WB-DWI using a 1.5TMR body coil. The images were reconstructed by a three-dimensional maximum intensity projection (3D-MIP) and black-white inversion technique. The lesions detected by WB-DWI were all plain MRI, and 35 cases were enhanced MRI. The number of lesions detected by WB-DWI and WB-DWI combined with routine scanning and the number of cases matching diagnosis were compared. The WB-DWI images of tumor lesions were analyzed, and the apparent diffusion coefficient (ADC) of the lesions was measured, and the ADC value of benign and malignant lesions was compared. There were 236 lesions in 63 patients with clinically confirmed tumors. 46 cases were diagnosed by WB-DWI, the diagnostic coincidence rate was 73.0%, and 207 lesions were detected. Fifty-eight cases were diagnosed by WB-DWI combined with routine scanning, the diagnostic coincidence rate was 92.1%, 236 lesions were detected. There were statistically significant differences in the number of lesions detected and the coincidence rate of tumor diagnosis between the two groups (P < 0.05). The average ADC value of malignant tumor ((1.04 ± 0.46) × 10⁻³ mm²/s) was lower than that of benign tumor ((2.53 ± 0.43) × 10⁻³ mm²/s), and the difference was statistically significant (P < 0.05). In conclusion, MR whole-body diffusion weighted imaging is safe, efficient, radiation-free, and highly sensitive, which is of great significance in the differential diagnosis of benign and malignant lesions. WB-DWI combined with MR routine scanning can further improve the detection rate of lesions and the coincidence rate of tumor diagnosis.

Magnetic resonance imaging of the pediatric mediastinum: updates, tips and tricks

Magnetic resonance imaging (MRI) of the pediatric mediastinum is challenging for the practicing radiologist. Many confounding factors add to the complexity of pediatric mediastinal MRI including small patient size, broad spectrum of mediastinal pathologies, motion artifacts and the need for sedation in a significant portion of children. However, with special attention to motion-reduction techniques and knowledge of pediatric-specific considerations, pediatric radiologists can help to provide accurate and timely diagnosis and also prevent multimodality imaging where MRI might be all that is needed. The purpose of this paper was present a practical review of pediatric mediastinal MRI with particular emphasis on diseases where MRI is the primary imaging modality of choice. Additionally, the author addresses those mediastinal processes for which MRI serves as a secondary problem-solving imaging tool.

Whole-body diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient values as prognostic factors in multiple myeloma

Multiple myeloma (MM) is a neoplasm of the B lymphocytes characterized by the uncontrolled proliferation of a plasmocyte clone. Magnetic resonance imaging (MRI) remains the most sensitive and specific imaging method for the detection of bone marrow infiltration, before macroscopic bone changes are visible, with evidence that the detection rate and overall performance of MRI could be enhanced by applying diffusion-weighted imaging (DWI). The aim of our research was to evaluate whether measuring apparent diffusion coefficient (ADC) values in newly diagnosed patients with MM could be a prognostic factor for the course of the disease and to ascertain whether there is any correlation with other prognostic factors in MM. A retrospective study was performed on a group of 32 patients with newly diagnosed MM that underwent at least two whole-body (WB)-MRIs; one before and one after induction therapy. Patients with advanced stage of disease showed an increased ADC value: Stage 2 vs. stage 1 (1.162 vs. 0.289, P=0.033), respectively, stage 3 vs. stage 1 (0.867 vs. 0.289, P=0.041). In addition, ADC values were inversely correlated with survival time: r=-0.641, P<0.001. According to the multivariate linear regression model, we observed that for every point of ADC value (before treatment) the survival was decreased/reduced by 14.5 months. Moreover, bortezomib therapy predicted an increase in the survival length/duration by 7.9 months. Our regression equation proved to be a good fit for the model, explaining 57.8% of survival duration (adjusted R²=0.578). In conclusion, the negative prognostic factors associated with WB-MRI are represented by high ADC values before treatment (for every point of ADC the survival was decreased by 14.5 months) and focal/diffuse marrow involvement.

Whole body FDG-PET/CT for the assessment of bone marrow infiltration in patients with newly diagnosed lymphoma

BACKGROUND

Positron emission tomography-computed tomography (PET-CT) and bone marrow biopsy are currently the common clinical examination of lymphoma infiltration. The aim of this research is to evaluate the value of PET-CT in diagnosis of bone marrow infiltration, clinical staging and pathological typing of lymphoma.

METHODS

153 cases were analyzed retrospectively to compare the consistency of PET-CT and bone marrow biopsy. We analyzed the sensitivity, accuracy and specificity of PET-CT in different clinical pathology of lymphoma.

RESULTS

The PET-CT sensitivity in detecting bone marrow infiltration is 54.3% with a specificity of 80.5% and accuracy of 74.5%. In aggressive B-cell lymphoma (DLBCL, HG-BL) and MZL, PET-CT results of bone marrow infiltration showed high accuracy of 88.1% and 83.3% respectively. The median value of SUVmax in the patients detected to have bone marrow infiltration by BMB was significantly higher than patients with BMB negative results among subgroups of aggressive B-cell lymphoma, MZL and T-NHL (p<.05).

CONCLUSION

PET-CT is significant in detecting bone marrow infiltration in certain pathological types of lymphoma. However pathological inconsistencies still exist between bone marrow biopsy and PET-CT, thus PET-CT cannot completely replace biopsy.

Role of advanced magnetic resonance imaging in the assessment of malignancies of the mediastinum

In the new era of functional magnetic resonance imaging (MRI), the utility of chest MRI is increasing exponentially due to several advances, including absence of ionizing radiation, excellent tissue contrast and high capability for lesion characterization and treatment monitoring. The application of several of these diagnostic weapons in a multiparametric fashion enables to better characterize thymic epithelial tumors and other mediastinal tumoral lesions, accurate assessment of the invasion of adjacent structures and detection of pathologic lymph nodes and metastasis. Also, “do not touch lesions” could be identified with the associated impact in the management of those patients. One of the hot-spots of the multiparametric chest MR is its ability to detect with acuity early response to treatment in patients with mediastinal malignant neoplasms. This has been related with higher rates of overall survival and progression free survival. Therefore, in this review we will analyze the current functional imaging techniques available (¹⁸F-Fluorodeoxiglucose positron emission tomography/computed tomography, diffusion-weighted imaging, dynamic contrast-enhanced MRI, diffusion tensor imaging and MR spectroscopy) for the evaluation of mediastinal lesions, with a focus in their correct acquisition and post-processing. Also, to review the clinical applications of these techniques in the diagnostic approach of benign and malignant conditions of the mediastinum.

Feasibility of diffusion-weighted imaging with DWIBS in staging Hodgkin lymphoma in pediatric patients: comparison with PET/CT

Objective

The aim of the study was to evaluate feasibility of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) method in diagnosing Hodgkin lymphoma in pediatric patients and to compare it with 18F-FDG PET/CT as a gold standard.

Materials and methods

Eleven patients (median age 14) with newly diagnosed Hodgkin lymphoma were examined with 18F-FDG PET/CT and MRI including whole-body DWIBS sequence (b = 0, 800 s/mm²), before the oncologic treatment. About 26 locations of lymphatic tissues were evaluated visually and quantitatively using ADC_mean (DWIBS) and SUV_max (18F-FDG PET/CT), respectively.

Results

All affected lymph node regions (n = 134) diagnosed in 18F-FDG PET/CT were found with DWIBS, presenting decreased diffusion. Significant correlation was found between ADC and SUV values (R² = − 0.37; p = 0.0001). Nevertheless, additional 33 regions were recognized only by DWIBS. They were significantly smaller than regions diagnosed by both methods.

Discussion

Agreement between DWIBS and 18F-FDG PET/CT for detection and staging of malignant lymphoma is high. DWIBS can be used for the evaluation of pediatric Hodgkin lymphoma.

Metabolic Tumor Volume Metrics in Lymphoma

Although visual assessment using the Deauville criteria is strongly recommended by guidelines for treatment response monitoring in all FDG-avid lymphoma histologies, the high rate of false-positives and concerns about interobserver variability have motivated the development of quantitative tools to facilitate objective measurement of tumor response in both routine and clinical trial settings. Imaging studies using functional quantitative measures play a significant role in profiling oncologic processes. These quantitative metrics allow for objective end points in multicenter clinical trials. However, the standardization of imaging procedures including image acquisition parameters, reconstruction and analytic measures, and validation of these methods are essential to enable an individualized treatment approach. A robust quality control program associated with the inclusion of proper scanner calibration, cross-calibration with dose calibrators and across other scanners is required for accurate quantitative measurements. In this section, we will review the technical and methodological considerations related to PET-derived quantitative metrics and the relevant published data to emphasize the potential value of these metrics in the prediction of patient prognosis in lymphoma.

ADC histogram analysis of muscle lymphoma-correlation with histopathology in a rare entity

OBJECTIVE:

Diffusion-weighted imaging is able to reflect histopathology architecture. A novel imaging approach, namely histogram analysis, is used to further characterize lesion on MRI. To correlate histogram parameters derived from apparent diffusion coefficient (ADC) maps with histopathology parameters in muscle lymphoma.

METHODS:

Eight patients (mean age 64.8 years, range 45-72 years) with histopathologically confirmed muscle lymphoma were retrospectively identified. Cell count, total nucleic and average nucleic areas were estimated using ImageJ. Additionally, Ki67-index was calculated. Diffusion-weightedimaging was obtained on a 1.5 T scanner by using the b-values of 0 and 1000 s mm^-2. Histogram analysis was performed as a whole lesion measurement by using a custom-made Matlab-based application.

RESULTS:

All ADC parameters showed a good to excellent interreader variability. Cell count correlated well with ADCmean (ρ = -0.76, p = 0.03) and ADCp75 (ρ =-0.79, p = 0.02). Kurtosis and entropy correlated with average nucleic area (ρ = -0.81, p = 0.02, ρ =0.88, p = 0.007, respectively). None of the analyzed ADC parameters correlated with total nucleic area and with Ki67-index.

CONCLUSION:

ADC histogram analysis parameters can reflect cellularity in muscle lymphoma.

ADVANCES IN KNOWLEDGE:

Histogram parameters derived from ADC maps can reflect several different cellularity parameters in muscle lymphoma.

Application of the apparent diffusion coefficient in magnetic resonance imaging in an assessment of the early response to treatment in Hodgkin's and non-Hodgkin's lymphoma - pilot study

Purpose

Lymphoproliferative neoplasms are the largest and most frequently diagnosed entities in the group of haematological malignancies. The aim of the study was to assess whether apparent diffusion coefficient (ADC) measured on the first day of the second cycle of chemotherapy could be a predictor of prognosis and of the final treatment’s outcome.

Material and methods

The study included 27 patients with diagnosed Hodgkin’s and non-Hodgkin’s lymphoma, who had magnetic resonance (MR) performed with diffusion weighted imaging/apparent diffusion coefficient (DWI/ADC) before and on the first day of the second cycle of chemotherapy. Imaging was performed using a 1.5 T MR scanner. ADC was measured in lymphoma infiltration in the area of the lowest signal in the ADC map and the highest signal on β 800 images in post-treatment study. After that, the corresponding area was determined in a pre-treatment study and an ADC value was measured.

Results

The difference between ADC values in pre-treatment (ADC = 720 mm²/s) and post-treatment (ADC = 1059 mm²/s) studies was statistically significant (p < 0.001). Cutoff values for estimating response to treatment were established at the level of ADC 1080 mm²/s, and ADC to muscle ratio at 0.82 in post-treatment study. Patients with ADC > 752 mm²/s before treatment manifested lower probability of progression than patients with ADC < 752 mm²/s.

Conclusions

ADC measurement’s before treatment and on the first day of the second cycle of chemotherapy can be used as a prognostic marker in lymphoma therapy. ADC values lower than 1080 mm²/s and an increase of the ratio after the treatment can be considered as a marker of disease progression.

Whole-Body MRI: Current Applications in Oncology

OBJECTIVE

The purpose of this article is to review current image acquisition and interpretation for whole-body MRI, clinical applications, and the emerging roles in oncologic imaging, especially in the assessment of bone marrow diseases.

CONCLUSION

Whole-body MRI is an emerging technique used for early diagnosis, staging, and assessment of therapeutic response in oncology. The improved accessibility and advances in technology, including widely available sequences (Dixon and DWI), have accelerated its deployment and acceptance in clinical practice.

Correlation between glycolytic activity on [18F]-FDG-PET and cell density on diffusion-weighted MRI in lymphoma at staging

BACKGROUND

[18F]-FDG-PET/MR carries a high diagnostic value in whole-body oncologic imaging and allows simultaneous quantitative measurements of glucose metabolism (SUV) and cell density (ADC).

PURPOSE

To determine the relationship between SUV and ADC values extracted from simultaneously acquired [18F]-FDG-PET/MR data of patients with FDG-avid lymphomas at staging.

STUDY TYPE

Prospective.

POPULATION

Patients with histologically proven lymphoma referred for staging.

FIELD STRENGTH/SEQUENCES

Hybrid PET/MR device (3T); axial, two-point Dixon, 3D, volume-interpolated, T₁ -weighted breath-hold sequence; coronal T₂ -weighted half-Fourier acquisition single-shot turbo spin-echo. Single-shot, echo-planar imaging-based, spectral adiabatic inversion recovery diffusion-weighted imaging.

ASSESSMENT

Staging was performed according to the modified Ann Arbor system by a board-certified radiologist and a board-certified nuclear medicine physician, blinded to the clinical and histological information, in consensus. SUVs and ADCs values were collected, for each positive nodal and extranodal region, from the lesion demonstrating the largest diameter.

STATISTICAL TESTS

Descriptive data included absolute frequencies and percentages for categorical data, and arithmetic means and 95% confidence intervals for scale-type data. The Pearson correlation coefficient was used to assess the relationship between SUVs and ADCs (P ≤ 0.05). Additional separate analyses were performed according to histological lymphoma subtype, for nodal and extranodal lesions and excluding bone lesions.

RESULTS

Overall, 100 patients were examined (55 males, 45 females; age ± SD in years, 51.6 ± 19.5). Histology revealed Hodgkin-lymphoma and non-Hodgkin-lymphoma in 26 and 74 patients, respectively. Twenty patients were stage I, 21 stage II, 24 stage III, and 31 stage IV on [18F]-FDG-PET/MR (ie, four patients negative at imaging). Based on 391 lesions (ie, 367 excluding bone lesions) no significant correlations between SUVmax and ADCmin, or between SUVmean and ADCmean, emerged (respectively, r = 0.091, P = 0.073, 95% CI [-0.01, 0.19] and r = -0.032, P = 0.527, 95% CI [-0.13, 0.07] including bone lesions; r = 0.06, P = 0.21, 95% CI [-0.04, 0.17] and r = -0.05, P = 0.32, 95% CI [-0.15, 0.05] excluding bone lesions). A significant correlation was observed only between ADCmean and SUVmean for follicular lymphoma (r = -0.33, P = 0.001).

DATA CONCLUSION

SUVs and ADCs were demonstrated to be independent biomarkers in lymphomas. A moderate correlation between SUVs and ADCs likely is present in follicular lymphoma.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1217-1226.

Meta-Analysis of the Correlation between Apparent Diffusion Coefficient and Standardized Uptake Value in Malignant Disease

The objective of this meta-analysis is to explore the correlation between the apparent diffusion coefficient (ADC) on diffusion-weighted MR and the standard uptake value (SUV) of ¹⁸F-FDG on PET/CT in patients with cancer. Databases such as PubMed (MEDLINE included), EMBASE, and Cochrane Database of Systematic Review were searched for relevant original articles that explored the correlation between SUV and ADC in English. After applying Fisher's r-to-z transformation, correlation coefficient (r) values were extracted from each study and 95% confidence intervals (CIs) were calculated. Sensitivity and subgroup analyses based on tumor type were performed to investigate the potential heterogeneity. Forty-nine studies were eligible for the meta-analysis, comprising 1927 patients. Pooled r for all studies was −0.35 (95% CI: −0.42–0.28) and exhibited a notable heterogeneity (I² = 78.4%; P < 0.01). In terms of the cancer type subgroup analysis, combined correlation coefficients of ADC/SUV range from −0.12 (lymphoma, n = 5) to −0.59 (pancreatic cancer, n = 2). We concluded that there is an average negative correlation between ADC and SUV in patients with cancer. Higher correlations were found in the brain tumor, cervix carcinoma, and pancreas cancer. However, a larger, prospective study is warranted to validate these findings in different cancer types.

[(68)Ga]DOTATATE PET/MRI and [(18)F]FDG PET/CT are complementary and superior to diffusion-weighted MR imaging for radioactive-iodine-refractory differentiated thyroid cancer

PURPOSE

The purpose of this study was to determine whether [(68)Ga]DOTATATE PET/MRI with diffusion-weighted imaging (DWI) can replace or complement [(18)F]FDG PET/CT in patients with radioactive-iodine (RAI)-refractory differentiated thyroid cancer (DTC).

METHODS

The study population comprised 12 patients with elevated thyroglobulin and a negative RAI scan after thyroidectomy and RAI remnant ablation who underwent both [(18)F]FDG PET/CT and [(68)Ga]DOTATATE PET/MRI within 8 weeks of each other. The presence of recurrent cancer was evaluated on a per-patient, per-organ and per-lesion basis. Histology, and prior and follow-up examinations served as the standard of reference.

RESULTS

Recurrent or metastatic tumour was confirmed in 11 of the 12 patients. [(68)Ga]DOTATATE PET(/MRI) correctly identified the tumour burden in all 11 patients, whereas in one patient local relapse was missed by [(18)F]FDG PET/CT. In the lesion-based analysis, overall lesion detection rates were 79/85 (93 %), 69/85 (81 %) and 27/82 (33 %) for [(18)F]FDG PET/CT, [(68)Ga]DOTATATE PET/MRI and DWI, respectively. [(18)F]FDG PET(/CT) was superior to [(68)Ga]DOTATATE PET(/MRI) in the overall evaluation and in the detection of pulmonary metastases. In the detection of extrapulmonary metastases, [(68)Ga]DOTATATE PET(/MRI) showed a higher sensitivity than [(18)F]FDG PET(/CT), at the cost of lower specificity. DWI achieved only poor sensitivity and was significantly inferior to [(18)F]FDG PET in the lesion-based evaluation in the detection of both extrapulmonary and pulmonary metastases.

CONCLUSION

[(18)F]FDG PET/CT was more sensitive than [(68)Ga]DOTATATE PET/MRI in the evaluation of RAI-refractory DTC, mostly because of its excellent ability to detect lung metastases. In the evaluation of extrapulmonary lesions, [(68)Ga]DOTATATE PET(/MRI) was more sensitive and [(18)F]FDG PET(/CT) more specific. Furthermore, DWI did not provide additional information and cannot replace [(18)F]FDG PET for postoperative monitoring of patients with suspected RAI-refractory DTC.

Image-guided radiation therapy in lymphoma management

Image-guided radiation therapy (IGRT) is a process of incorporating imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI), Positron emission tomography (PET), and ultrasound (US) during radiation therapy (RT) to improve treatment accuracy. It allows real-time or near real-time visualization of anatomical information to ensure that the target is in its position as planned. In addition, changes in tumor volume and location due to organ motion during treatment can be also compensated. IGRT has been gaining popularity and acceptance rapidly in RT over the past 10 years, and many published data have been reported on prostate, bladder, head and neck, and gastrointestinal cancers. However, the role of IGRT in lymphoma management is not well defined as there are only very limited published data currently available. The scope of this paper is to review the current use of IGRT in the management of lymphoma. The technical and clinical aspects of IGRT, lymphoma imaging studies, the current role of IGRT in lymphoma management and future directions will be discussed.