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OBJECTIVES: Intra-arterial radionuclide therapy (IART) treatment allows direct delivery of 177Lu-DOTATATE to the overexpressed somatostatin-positive neuroendocrine liver metastases, which led to higher tumour concentration compared with systemic radionuclide therapy (SRT). The aim was to evaluate and compare the absorbed doses of both IART and SRT to organs and hepatic metastatic sites.METHODS A: total of 48 patients received SRT and IART. In SRT, activity was administered intravenously, whereas in IART, activity was administered directly into hepatic arteries. The sequential whole-body images were acquired at 2, 4, 24, 72 and 160 h. The reconstructed whole-body planar and single-photon emission computed tomography-computed tomography images were processed using the Dosimetry Toolkit for the estimation of normalized cumulated activity in the organs and tumour lesions. The absorbed dose was computed using OLINDA EXM 2.0 software.RESULTS: The median absorbed dose (mGy/MBq) of kidneys and spleen in IART was compared with SRT and found to be decreased by 30.7% (P = 0.03) and 37.5% (P = 0.08), whereas it was found to be increased by 40% (P = 0.26) and 8.1% (P = 0.28) in the liver and lungs. The median dose (mGy/MBq) of tumours determined in IART was found to be increased by 62.2% (P = 0.04).CONCLUSION: IART with 177Lu-DOTATATE significantly increases tumour dose while reducing overall systemic toxicity in comparison to SRT treatment. After considering the maximum tolerance limit of kidneys in peptide receptor radionuclide therapy, the number of treatment cycles and injected activity can be optimized further with IART for better response and survival.

BACKGROUND: 177Lu-prostate-specific membrane antigen (PSMA) gained popularity as a choice of agent in the treatment of patients with advanced prostate cancer or metastatic castration-resistant stage of prostate carcinoma (mCRPC) diseases. However, this treatment may cause fatal effects, probably due to unintended irradiation of normal organs. We performed an extensive systematic review to assess the organs at risk and the absorbed dose received by tumor lesions in 177Lu-PSMA therapy.DESIGN: In this review, published peer-reviewed articles that cover clinical dosimetry in patients following peptide radionuclide ligand therapy using 177Lu-PSMA have been included. Two senior researchers independently checked the articles for inclusion. A systematic search in the database was made using PubMed, Publons and DOAJ. All selected articles were categorized into three groups: (1) clinical studies with the technical description of dosimetry in 177Lu-PSMA therapy (2) organ dosimetry in 177Lu-PSMA therapy or (3) tumor dosimetry in 177Lu-PSMA therapy.RESULT: In total, 182 citations were identified on PSMA therapy and 17 original articles on 177Lu-PSMA dosimetry were recognized as eligible for review. The median absorbed dose per unit of administered activity for kidneys, salivary, liver, spleen, lacrimal and bone marrow was 0.55, 0.81, 0.1, 0.1, 2.26 and 0.03 Gy/GBq, respectively. The median absorbed dose per unit of activity for tumor lesions was found in a range of 2.71-10.94 Gy/GBq.CONCLUSION: 177Lu-PSMA systemic radiation therapy (SRT) is a well-tolerated and reliable treatment option against the management of the mCRPC stage of prostate carcinoma. Lacrimal glands and salivary glands are the major critical organs in 177Lu-PSMA SRT. Besides, tumors receive 3-6 times higher absorbed doses compared to organs at risk.

BACKGROUND: 177Lu-prostate-specific membrane antigen (PSMA) gained popularity as a choice of agent in the treatment of patients with advanced prostate cancer or metastatic castration-resistant stage of prostate carcinoma (mCRPC) diseases. However, this treatment may cause fatal effects, probably due to unintended irradiation of normal organs. We performed an extensive systematic review to assess the organs at risk and the absorbed dose received by tumor lesions in 177Lu-PSMA therapy.DESIGN: In this review, published peer-reviewed articles that cover clinical dosimetry in patients following peptide radionuclide ligand therapy using 177Lu-PSMA have been included. Two senior researchers independently checked the articles for inclusion. A systematic search in the database was made using PubMed, Publons and DOAJ. All selected articles were categorized into three groups: (1) clinical studies with the technical description of dosimetry in 177Lu-PSMA therapy (2) organ dosimetry in 177Lu-PSMA therapy or (3) tumor dosimetry in 177Lu-PSMA therapy.RESULT: In total, 182 citations were identified on PSMA therapy and 17 original articles on 177Lu-PSMA dosimetry were recognized as eligible for review. The median absorbed dose per unit of administered activity for kidneys, salivary, liver, spleen, lacrimal and bone marrow was 0.55, 0.81, 0.1, 0.1, 2.26 and 0.03 Gy/GBq, respectively. The median absorbed dose per unit of activity for tumor lesions was found in a range of 2.71-10.94 Gy/GBq.CONCLUSION: 177Lu-PSMA systemic radiation therapy (SRT) is a well-tolerated and reliable treatment option against the management of the mCRPC stage of prostate carcinoma. Lacrimal glands and salivary glands are the major critical organs in 177Lu-PSMA SRT. Besides, tumors receive 3-6 times higher absorbed doses compared to organs at risk.

OBJECTIVES: Internal organ dosimetry is an important procedure to demonstrate the reliable application of 177Lu-trastuzumab radioimmunotherapy for human epidermal growth factor receptor-positive metastatic breast cancers. We are reporting the first human dosimetry study for 177Lu-trastuzumab. Another objective of our study was to calculate and compare the absorbed doses for normal organs and tumor lesions in patients before radioimmunotherapy with 177Lu-trastuzumab using two different imaging scenarios.METHODS: Eleven patients (48.27 ± 8.95 years) with a history of metastatic breast cancer were included in the study. Postadministration of 177Lu-trastuzumab (351.09 ± 23.89 MBq/2 mg), acquisition was performed using planar and hybrid imaging scenarios at 4, 24, 72 and 168 h. Single-photon emission computed tomography/computed tomography imaging was performed at 72 h postinjection. Acquired images were processed using Dosimetry Toolkit software for the estimation of normalized cumulated activity in organs and tumor lesions. OLINDA/EXM 2.0 software was used for absorbed dose calculation in both scenarios.RESULTS: Significant difference in normalized cumulated activity and the absorbed dose is noted between two imaging scenarios for the organs and tumor lesions (P < 0.05). Mean absorbed dose (mGy/MBq) estimated from heart, lungs, liver, spleen, kidney, adrenal, pancreas and colon using planar and hybrid scenarios were 0.81 ± 0.19 and 0.63 ± 0.17; 0.75 ± 0.13 and 0.32 ± 0.06; 1.26 ± 0.25 and 1.01 ± 0.17; 0.68 ± 0.22 and 0.53 ± 0.16; 0.91 ± 0.3 and 0.69 ± 0.24; 0.18 ± 0.04 and 0.11 ± 0.02; 0.25 ± 0.22 and 0.09 ± 0.02 and 0.75 ± 0.61 and 0.44 ± 0.28, respectively.CONCLUSIONS: On the basis of our dosimetric evaluation, we concluded that radioimmunotherapy with 177Lu-trastuzumab is well tolerated to be implemented in routine clinical practice against HER2 positive metastatic breast cancer. Liver is the main critical organ at risk. Hybrid scenario de

OBJECTIVES: Internal organ dosimetry is an important procedure to demonstrate the reliable application of 177Lu-trastuzumab radioimmunotherapy for human epidermal growth factor receptor-positive metastatic breast cancers. We are reporting the first human dosimetry study for 177Lu-trastuzumab. Another objective of our study was to calculate and compare the absorbed doses for normal organs and tumor lesions in patients before radioimmunotherapy with 177Lu-trastuzumab using two different imaging scenarios.METHODS: Eleven patients (48.27 ± 8.95 years) with a history of metastatic breast cancer were included in the study. Postadministration of 177Lu-trastuzumab (351.09 ± 23.89 MBq/2 mg), acquisition was performed using planar and hybrid imaging scenarios at 4, 24, 72 and 168 h. Single-photon emission computed tomography/computed tomography imaging was performed at 72 h postinjection. Acquired images were processed using Dosimetry Toolkit software for the estimation of normalized cumulated activity in organs and tumor lesions. OLINDA/EXM 2.0 software was used for absorbed dose calculation in both scenarios.RESULTS: Significant difference in normalized cumulated activity and the absorbed dose is noted between two imaging scenarios for the organs and tumor lesions (P < 0.05). Mean absorbed dose (mGy/MBq) estimated from heart, lungs, liver, spleen, kidney, adrenal, pancreas and colon using planar and hybrid scenarios were 0.81 ± 0.19 and 0.63 ± 0.17; 0.75 ± 0.13 and 0.32 ± 0.06; 1.26 ± 0.25 and 1.01 ± 0.17; 0.68 ± 0.22 and 0.53 ± 0.16; 0.91 ± 0.3 and 0.69 ± 0.24; 0.18 ± 0.04 and 0.11 ± 0.02; 0.25 ± 0.22 and 0.09 ± 0.02 and 0.75 ± 0.61 and 0.44 ± 0.28, respectively.CONCLUSIONS: On the basis of our dosimetric evaluation, we concluded that radioimmunotherapy with 177Lu-trastuzumab is well tolerated to be implemented in routine clinical practice against HER2 positive metastatic breast cancer. Liver is the main critical organ at risk. Hybrid scenario de